/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if HAVE_PAM #include #endif #if HAVE_SELINUX #include #endif #if HAVE_SECCOMP #include #endif #if HAVE_APPARMOR #include #endif #include "sd-messages.h" #include "acl-util.h" #include "af-list.h" #include "alloc-util.h" #if HAVE_APPARMOR #include "apparmor-util.h" #endif #include "argv-util.h" #include "async.h" #include "barrier.h" #include "bpf-lsm.h" #include "cap-list.h" #include "capability-util.h" #include "cgroup-setup.h" #include "chase.h" #include "chown-recursive.h" #include "constants.h" #include "cpu-set-util.h" #include "creds-util.h" #include "data-fd-util.h" #include "env-file.h" #include "env-util.h" #include "errno-list.h" #include "escape.h" #include "execute.h" #include "exit-status.h" #include "fd-util.h" #include "fileio.h" #include "format-util.h" #include "glob-util.h" #include "hexdecoct.h" #include "io-util.h" #include "ioprio-util.h" #include "label.h" #include "log.h" #include "macro.h" #include "manager.h" #include "manager-dump.h" #include "memory-util.h" #include "missing_fs.h" #include "missing_ioprio.h" #include "missing_prctl.h" #include "mkdir-label.h" #include "mount-util.h" #include "mountpoint-util.h" #include "namespace.h" #include "parse-util.h" #include "path-util.h" #include "proc-cmdline.h" #include "process-util.h" #include "psi-util.h" #include "random-util.h" #include "recurse-dir.h" #include "rlimit-util.h" #include "rm-rf.h" #if HAVE_SECCOMP #include "seccomp-util.h" #endif #include "securebits-util.h" #include "selinux-util.h" #include "signal-util.h" #include "smack-util.h" #include "socket-util.h" #include "sort-util.h" #include "special.h" #include "stat-util.h" #include "string-table.h" #include "string-util.h" #include "strv.h" #include "syslog-util.h" #include "terminal-util.h" #include "tmpfile-util.h" #include "umask-util.h" #include "unit-serialize.h" #include "user-util.h" #include "utmp-wtmp.h" #define IDLE_TIMEOUT_USEC (5*USEC_PER_SEC) #define IDLE_TIMEOUT2_USEC (1*USEC_PER_SEC) #define SNDBUF_SIZE (8*1024*1024) static int shift_fds(int fds[], size_t n_fds) { if (n_fds <= 0) return 0; /* Modifies the fds array! (sorts it) */ assert(fds); for (int start = 0;;) { int restart_from = -1; for (int i = start; i < (int) n_fds; i++) { int nfd; /* Already at right index? */ if (fds[i] == i+3) continue; nfd = fcntl(fds[i], F_DUPFD, i + 3); if (nfd < 0) return -errno; safe_close(fds[i]); fds[i] = nfd; /* Hmm, the fd we wanted isn't free? Then * let's remember that and try again from here */ if (nfd != i+3 && restart_from < 0) restart_from = i; } if (restart_from < 0) break; start = restart_from; } return 0; } static int flags_fds( const int fds[], size_t n_socket_fds, size_t n_fds, bool nonblock) { int r; if (n_fds <= 0) return 0; assert(fds); /* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags. * O_NONBLOCK only applies to socket activation though. */ for (size_t i = 0; i < n_fds; i++) { if (i < n_socket_fds) { r = fd_nonblock(fds[i], nonblock); if (r < 0) return r; } /* We unconditionally drop FD_CLOEXEC from the fds, * since after all we want to pass these fds to our * children */ r = fd_cloexec(fds[i], false); if (r < 0) return r; } return 0; } static const char *exec_context_tty_path(const ExecContext *context) { assert(context); if (context->stdio_as_fds) return NULL; if (context->tty_path) return context->tty_path; return "/dev/console"; } static int exec_context_tty_size(const ExecContext *context, unsigned *ret_rows, unsigned *ret_cols) { _cleanup_free_ char *rowskey = NULL, *rowsvalue = NULL, *colskey = NULL, *colsvalue = NULL; unsigned rows, cols; const char *tty; int r; assert(context); assert(ret_rows); assert(ret_cols); rows = context->tty_rows; cols = context->tty_cols; tty = exec_context_tty_path(context); if (!tty || (rows != UINT_MAX && cols != UINT_MAX)) { *ret_rows = rows; *ret_cols = cols; return 0; } tty = skip_dev_prefix(tty); if (!in_charset(tty, ALPHANUMERICAL)) { log_debug("%s contains non-alphanumeric characters, ignoring", tty); *ret_rows = rows; *ret_cols = cols; return 0; } rowskey = strjoin("systemd.tty.rows.", tty); if (!rowskey) return -ENOMEM; colskey = strjoin("systemd.tty.columns.", tty); if (!colskey) return -ENOMEM; r = proc_cmdline_get_key_many(/* flags = */ 0, rowskey, &rowsvalue, colskey, &colsvalue); if (r < 0) log_debug_errno(r, "Failed to read TTY size of %s from kernel cmdline, ignoring: %m", tty); if (rows == UINT_MAX && rowsvalue) { r = safe_atou(rowsvalue, &rows); if (r < 0) log_debug_errno(r, "Failed to parse %s=%s, ignoring: %m", rowskey, rowsvalue); } if (cols == UINT_MAX && colsvalue) { r = safe_atou(colsvalue, &cols); if (r < 0) log_debug_errno(r, "Failed to parse %s=%s, ignoring: %m", colskey, colsvalue); } *ret_rows = rows; *ret_cols = cols; return 0; } static void exec_context_tty_reset(const ExecContext *context, const ExecParameters *p) { const char *path; assert(context); path = exec_context_tty_path(context); if (context->tty_vhangup) { if (p && p->stdin_fd >= 0) (void) terminal_vhangup_fd(p->stdin_fd); else if (path) (void) terminal_vhangup(path); } if (context->tty_reset) { if (p && p->stdin_fd >= 0) (void) reset_terminal_fd(p->stdin_fd, true); else if (path) (void) reset_terminal(path); } if (p && p->stdin_fd >= 0) { unsigned rows = context->tty_rows, cols = context->tty_cols; (void) exec_context_tty_size(context, &rows, &cols); (void) terminal_set_size_fd(p->stdin_fd, path, rows, cols); } if (context->tty_vt_disallocate && path) (void) vt_disallocate(path); } static bool is_terminal_input(ExecInput i) { return IN_SET(i, EXEC_INPUT_TTY, EXEC_INPUT_TTY_FORCE, EXEC_INPUT_TTY_FAIL); } static bool is_terminal_output(ExecOutput o) { return IN_SET(o, EXEC_OUTPUT_TTY, EXEC_OUTPUT_KMSG_AND_CONSOLE, EXEC_OUTPUT_JOURNAL_AND_CONSOLE); } static bool is_kmsg_output(ExecOutput o) { return IN_SET(o, EXEC_OUTPUT_KMSG, EXEC_OUTPUT_KMSG_AND_CONSOLE); } static bool exec_context_needs_term(const ExecContext *c) { assert(c); /* Return true if the execution context suggests we should set $TERM to something useful. */ if (is_terminal_input(c->std_input)) return true; if (is_terminal_output(c->std_output)) return true; if (is_terminal_output(c->std_error)) return true; return !!c->tty_path; } static int open_null_as(int flags, int nfd) { int fd; assert(nfd >= 0); fd = open("/dev/null", flags|O_NOCTTY); if (fd < 0) return -errno; return move_fd(fd, nfd, false); } static int connect_journal_socket( int fd, const char *log_namespace, uid_t uid, gid_t gid) { uid_t olduid = UID_INVALID; gid_t oldgid = GID_INVALID; const char *j; int r; j = log_namespace ? strjoina("/run/systemd/journal.", log_namespace, "/stdout") : "/run/systemd/journal/stdout"; if (gid_is_valid(gid)) { oldgid = getgid(); if (setegid(gid) < 0) return -errno; } if (uid_is_valid(uid)) { olduid = getuid(); if (seteuid(uid) < 0) { r = -errno; goto restore_gid; } } r = connect_unix_path(fd, AT_FDCWD, j); /* If we fail to restore the uid or gid, things will likely fail later on. This should only happen if an LSM interferes. */ if (uid_is_valid(uid)) (void) seteuid(olduid); restore_gid: if (gid_is_valid(gid)) (void) setegid(oldgid); return r; } static int connect_logger_as( const Unit *unit, const ExecContext *context, const ExecParameters *params, ExecOutput output, const char *ident, int nfd, uid_t uid, gid_t gid) { _cleanup_close_ int fd = -EBADF; int r; assert(context); assert(params); assert(output < _EXEC_OUTPUT_MAX); assert(ident); assert(nfd >= 0); fd = socket(AF_UNIX, SOCK_STREAM, 0); if (fd < 0) return -errno; r = connect_journal_socket(fd, context->log_namespace, uid, gid); if (r < 0) return r; if (shutdown(fd, SHUT_RD) < 0) return -errno; (void) fd_inc_sndbuf(fd, SNDBUF_SIZE); if (dprintf(fd, "%s\n" "%s\n" "%i\n" "%i\n" "%i\n" "%i\n" "%i\n", context->syslog_identifier ?: ident, params->flags & EXEC_PASS_LOG_UNIT ? unit->id : "", context->syslog_priority, !!context->syslog_level_prefix, false, is_kmsg_output(output), is_terminal_output(output)) < 0) return -errno; return move_fd(TAKE_FD(fd), nfd, false); } static int open_terminal_as(const char *path, int flags, int nfd) { int fd; assert(path); assert(nfd >= 0); fd = open_terminal(path, flags | O_NOCTTY); if (fd < 0) return fd; return move_fd(fd, nfd, false); } static int acquire_path(const char *path, int flags, mode_t mode) { _cleanup_close_ int fd = -EBADF; int r; assert(path); if (IN_SET(flags & O_ACCMODE, O_WRONLY, O_RDWR)) flags |= O_CREAT; fd = open(path, flags|O_NOCTTY, mode); if (fd >= 0) return TAKE_FD(fd); if (errno != ENXIO) /* ENXIO is returned when we try to open() an AF_UNIX file system socket on Linux */ return -errno; /* So, it appears the specified path could be an AF_UNIX socket. Let's see if we can connect to it. */ fd = socket(AF_UNIX, SOCK_STREAM, 0); if (fd < 0) return -errno; r = connect_unix_path(fd, AT_FDCWD, path); if (IN_SET(r, -ENOTSOCK, -EINVAL)) /* Propagate initial error if we get ENOTSOCK or EINVAL, i.e. we have indication that this * wasn't an AF_UNIX socket after all */ return -ENXIO; if (r < 0) return r; if ((flags & O_ACCMODE) == O_RDONLY) r = shutdown(fd, SHUT_WR); else if ((flags & O_ACCMODE) == O_WRONLY) r = shutdown(fd, SHUT_RD); else r = 0; if (r < 0) return -errno; return TAKE_FD(fd); } static int fixup_input( const ExecContext *context, int socket_fd, bool apply_tty_stdin) { ExecInput std_input; assert(context); std_input = context->std_input; if (is_terminal_input(std_input) && !apply_tty_stdin) return EXEC_INPUT_NULL; if (std_input == EXEC_INPUT_SOCKET && socket_fd < 0) return EXEC_INPUT_NULL; if (std_input == EXEC_INPUT_DATA && context->stdin_data_size == 0) return EXEC_INPUT_NULL; return std_input; } static int fixup_output(ExecOutput output, int socket_fd) { if (output == EXEC_OUTPUT_SOCKET && socket_fd < 0) return EXEC_OUTPUT_INHERIT; return output; } static int setup_input( const ExecContext *context, const ExecParameters *params, int socket_fd, const int named_iofds[static 3]) { ExecInput i; int r; assert(context); assert(params); assert(named_iofds); if (params->stdin_fd >= 0) { if (dup2(params->stdin_fd, STDIN_FILENO) < 0) return -errno; /* Try to make this the controlling tty, if it is a tty, and reset it */ if (isatty(STDIN_FILENO)) { unsigned rows = context->tty_rows, cols = context->tty_cols; (void) exec_context_tty_size(context, &rows, &cols); (void) ioctl(STDIN_FILENO, TIOCSCTTY, context->std_input == EXEC_INPUT_TTY_FORCE); (void) reset_terminal_fd(STDIN_FILENO, true); (void) terminal_set_size_fd(STDIN_FILENO, NULL, rows, cols); } return STDIN_FILENO; } i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN); switch (i) { case EXEC_INPUT_NULL: return open_null_as(O_RDONLY, STDIN_FILENO); case EXEC_INPUT_TTY: case EXEC_INPUT_TTY_FORCE: case EXEC_INPUT_TTY_FAIL: { unsigned rows, cols; int fd; fd = acquire_terminal(exec_context_tty_path(context), i == EXEC_INPUT_TTY_FAIL ? ACQUIRE_TERMINAL_TRY : i == EXEC_INPUT_TTY_FORCE ? ACQUIRE_TERMINAL_FORCE : ACQUIRE_TERMINAL_WAIT, USEC_INFINITY); if (fd < 0) return fd; r = exec_context_tty_size(context, &rows, &cols); if (r < 0) return r; r = terminal_set_size_fd(fd, exec_context_tty_path(context), rows, cols); if (r < 0) return r; return move_fd(fd, STDIN_FILENO, false); } case EXEC_INPUT_SOCKET: assert(socket_fd >= 0); return RET_NERRNO(dup2(socket_fd, STDIN_FILENO)); case EXEC_INPUT_NAMED_FD: assert(named_iofds[STDIN_FILENO] >= 0); (void) fd_nonblock(named_iofds[STDIN_FILENO], false); return RET_NERRNO(dup2(named_iofds[STDIN_FILENO], STDIN_FILENO)); case EXEC_INPUT_DATA: { int fd; fd = acquire_data_fd(context->stdin_data, context->stdin_data_size, 0); if (fd < 0) return fd; return move_fd(fd, STDIN_FILENO, false); } case EXEC_INPUT_FILE: { bool rw; int fd; assert(context->stdio_file[STDIN_FILENO]); rw = (context->std_output == EXEC_OUTPUT_FILE && streq_ptr(context->stdio_file[STDIN_FILENO], context->stdio_file[STDOUT_FILENO])) || (context->std_error == EXEC_OUTPUT_FILE && streq_ptr(context->stdio_file[STDIN_FILENO], context->stdio_file[STDERR_FILENO])); fd = acquire_path(context->stdio_file[STDIN_FILENO], rw ? O_RDWR : O_RDONLY, 0666 & ~context->umask); if (fd < 0) return fd; return move_fd(fd, STDIN_FILENO, false); } default: assert_not_reached(); } } static bool can_inherit_stderr_from_stdout( const ExecContext *context, ExecOutput o, ExecOutput e) { assert(context); /* Returns true, if given the specified STDERR and STDOUT output we can directly dup() the stdout fd to the * stderr fd */ if (e == EXEC_OUTPUT_INHERIT) return true; if (e != o) return false; if (e == EXEC_OUTPUT_NAMED_FD) return streq_ptr(context->stdio_fdname[STDOUT_FILENO], context->stdio_fdname[STDERR_FILENO]); if (IN_SET(e, EXEC_OUTPUT_FILE, EXEC_OUTPUT_FILE_APPEND, EXEC_OUTPUT_FILE_TRUNCATE)) return streq_ptr(context->stdio_file[STDOUT_FILENO], context->stdio_file[STDERR_FILENO]); return true; } static int setup_output( const Unit *unit, const ExecContext *context, const ExecParameters *params, int fileno, int socket_fd, const int named_iofds[static 3], const char *ident, uid_t uid, gid_t gid, dev_t *journal_stream_dev, ino_t *journal_stream_ino) { ExecOutput o; ExecInput i; int r; assert(unit); assert(context); assert(params); assert(ident); assert(journal_stream_dev); assert(journal_stream_ino); if (fileno == STDOUT_FILENO && params->stdout_fd >= 0) { if (dup2(params->stdout_fd, STDOUT_FILENO) < 0) return -errno; return STDOUT_FILENO; } if (fileno == STDERR_FILENO && params->stderr_fd >= 0) { if (dup2(params->stderr_fd, STDERR_FILENO) < 0) return -errno; return STDERR_FILENO; } i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN); o = fixup_output(context->std_output, socket_fd); if (fileno == STDERR_FILENO) { ExecOutput e; e = fixup_output(context->std_error, socket_fd); /* This expects the input and output are already set up */ /* Don't change the stderr file descriptor if we inherit all * the way and are not on a tty */ if (e == EXEC_OUTPUT_INHERIT && o == EXEC_OUTPUT_INHERIT && i == EXEC_INPUT_NULL && !is_terminal_input(context->std_input) && getppid() != 1) return fileno; /* Duplicate from stdout if possible */ if (can_inherit_stderr_from_stdout(context, o, e)) return RET_NERRNO(dup2(STDOUT_FILENO, fileno)); o = e; } else if (o == EXEC_OUTPUT_INHERIT) { /* If input got downgraded, inherit the original value */ if (i == EXEC_INPUT_NULL && is_terminal_input(context->std_input)) return open_terminal_as(exec_context_tty_path(context), O_WRONLY, fileno); /* If the input is connected to anything that's not a /dev/null or a data fd, inherit that... */ if (!IN_SET(i, EXEC_INPUT_NULL, EXEC_INPUT_DATA)) return RET_NERRNO(dup2(STDIN_FILENO, fileno)); /* If we are not started from PID 1 we just inherit STDOUT from our parent process. */ if (getppid() != 1) return fileno; /* We need to open /dev/null here anew, to get the right access mode. */ return open_null_as(O_WRONLY, fileno); } switch (o) { case EXEC_OUTPUT_NULL: return open_null_as(O_WRONLY, fileno); case EXEC_OUTPUT_TTY: if (is_terminal_input(i)) return RET_NERRNO(dup2(STDIN_FILENO, fileno)); /* We don't reset the terminal if this is just about output */ return open_terminal_as(exec_context_tty_path(context), O_WRONLY, fileno); case EXEC_OUTPUT_KMSG: case EXEC_OUTPUT_KMSG_AND_CONSOLE: case EXEC_OUTPUT_JOURNAL: case EXEC_OUTPUT_JOURNAL_AND_CONSOLE: r = connect_logger_as(unit, context, params, o, ident, fileno, uid, gid); if (r < 0) { log_unit_warning_errno(unit, r, "Failed to connect %s to the journal socket, ignoring: %m", fileno == STDOUT_FILENO ? "stdout" : "stderr"); r = open_null_as(O_WRONLY, fileno); } else { struct stat st; /* If we connected this fd to the journal via a stream, patch the device/inode into the passed * parameters, but only then. This is useful so that we can set $JOURNAL_STREAM that permits * services to detect whether they are connected to the journal or not. * * If both stdout and stderr are connected to a stream then let's make sure to store the data * about STDERR as that's usually the best way to do logging. */ if (fstat(fileno, &st) >= 0 && (*journal_stream_ino == 0 || fileno == STDERR_FILENO)) { *journal_stream_dev = st.st_dev; *journal_stream_ino = st.st_ino; } } return r; case EXEC_OUTPUT_SOCKET: assert(socket_fd >= 0); return RET_NERRNO(dup2(socket_fd, fileno)); case EXEC_OUTPUT_NAMED_FD: assert(named_iofds[fileno] >= 0); (void) fd_nonblock(named_iofds[fileno], false); return RET_NERRNO(dup2(named_iofds[fileno], fileno)); case EXEC_OUTPUT_FILE: case EXEC_OUTPUT_FILE_APPEND: case EXEC_OUTPUT_FILE_TRUNCATE: { bool rw; int fd, flags; assert(context->stdio_file[fileno]); rw = context->std_input == EXEC_INPUT_FILE && streq_ptr(context->stdio_file[fileno], context->stdio_file[STDIN_FILENO]); if (rw) return RET_NERRNO(dup2(STDIN_FILENO, fileno)); flags = O_WRONLY; if (o == EXEC_OUTPUT_FILE_APPEND) flags |= O_APPEND; else if (o == EXEC_OUTPUT_FILE_TRUNCATE) flags |= O_TRUNC; fd = acquire_path(context->stdio_file[fileno], flags, 0666 & ~context->umask); if (fd < 0) return fd; return move_fd(fd, fileno, 0); } default: assert_not_reached(); } } static int chown_terminal(int fd, uid_t uid) { int r; assert(fd >= 0); /* Before we chown/chmod the TTY, let's ensure this is actually a tty */ if (isatty(fd) < 1) { if (IN_SET(errno, EINVAL, ENOTTY)) return 0; /* not a tty */ return -errno; } /* This might fail. What matters are the results. */ r = fchmod_and_chown(fd, TTY_MODE, uid, GID_INVALID); if (r < 0) return r; return 1; } static int setup_confirm_stdio( const ExecContext *context, const char *vc, int *ret_saved_stdin, int *ret_saved_stdout) { _cleanup_close_ int fd = -EBADF, saved_stdin = -EBADF, saved_stdout = -EBADF; unsigned rows, cols; int r; assert(ret_saved_stdin); assert(ret_saved_stdout); saved_stdin = fcntl(STDIN_FILENO, F_DUPFD, 3); if (saved_stdin < 0) return -errno; saved_stdout = fcntl(STDOUT_FILENO, F_DUPFD, 3); if (saved_stdout < 0) return -errno; fd = acquire_terminal(vc, ACQUIRE_TERMINAL_WAIT, DEFAULT_CONFIRM_USEC); if (fd < 0) return fd; r = chown_terminal(fd, getuid()); if (r < 0) return r; r = reset_terminal_fd(fd, true); if (r < 0) return r; r = exec_context_tty_size(context, &rows, &cols); if (r < 0) return r; r = terminal_set_size_fd(fd, vc, rows, cols); if (r < 0) return r; r = rearrange_stdio(fd, fd, STDERR_FILENO); /* Invalidates 'fd' also on failure */ TAKE_FD(fd); if (r < 0) return r; *ret_saved_stdin = TAKE_FD(saved_stdin); *ret_saved_stdout = TAKE_FD(saved_stdout); return 0; } static void write_confirm_error_fd(int err, int fd, const Unit *u) { assert(err < 0); if (err == -ETIMEDOUT) dprintf(fd, "Confirmation question timed out for %s, assuming positive response.\n", u->id); else { errno = -err; dprintf(fd, "Couldn't ask confirmation for %s: %m, assuming positive response.\n", u->id); } } static void write_confirm_error(int err, const char *vc, const Unit *u) { _cleanup_close_ int fd = -EBADF; assert(vc); fd = open_terminal(vc, O_WRONLY|O_NOCTTY|O_CLOEXEC); if (fd < 0) return; write_confirm_error_fd(err, fd, u); } static int restore_confirm_stdio(int *saved_stdin, int *saved_stdout) { int r = 0; assert(saved_stdin); assert(saved_stdout); release_terminal(); if (*saved_stdin >= 0) if (dup2(*saved_stdin, STDIN_FILENO) < 0) r = -errno; if (*saved_stdout >= 0) if (dup2(*saved_stdout, STDOUT_FILENO) < 0) r = -errno; *saved_stdin = safe_close(*saved_stdin); *saved_stdout = safe_close(*saved_stdout); return r; } enum { CONFIRM_PRETEND_FAILURE = -1, CONFIRM_PRETEND_SUCCESS = 0, CONFIRM_EXECUTE = 1, }; static int ask_for_confirmation(const ExecContext *context, const char *vc, Unit *u, const char *cmdline) { int saved_stdout = -1, saved_stdin = -1, r; _cleanup_free_ char *e = NULL; char c; /* For any internal errors, assume a positive response. */ r = setup_confirm_stdio(context, vc, &saved_stdin, &saved_stdout); if (r < 0) { write_confirm_error(r, vc, u); return CONFIRM_EXECUTE; } /* confirm_spawn might have been disabled while we were sleeping. */ if (manager_is_confirm_spawn_disabled(u->manager)) { r = 1; goto restore_stdio; } e = ellipsize(cmdline, 60, 100); if (!e) { log_oom(); r = CONFIRM_EXECUTE; goto restore_stdio; } for (;;) { r = ask_char(&c, "yfshiDjcn", "Execute %s? [y, f, s – h for help] ", e); if (r < 0) { write_confirm_error_fd(r, STDOUT_FILENO, u); r = CONFIRM_EXECUTE; goto restore_stdio; } switch (c) { case 'c': printf("Resuming normal execution.\n"); manager_disable_confirm_spawn(); r = 1; break; case 'D': unit_dump(u, stdout, " "); continue; /* ask again */ case 'f': printf("Failing execution.\n"); r = CONFIRM_PRETEND_FAILURE; break; case 'h': printf(" c - continue, proceed without asking anymore\n" " D - dump, show the state of the unit\n" " f - fail, don't execute the command and pretend it failed\n" " h - help\n" " i - info, show a short summary of the unit\n" " j - jobs, show jobs that are in progress\n" " s - skip, don't execute the command and pretend it succeeded\n" " y - yes, execute the command\n"); continue; /* ask again */ case 'i': printf(" Description: %s\n" " Unit: %s\n" " Command: %s\n", u->id, u->description, cmdline); continue; /* ask again */ case 'j': manager_dump_jobs(u->manager, stdout, /* patterns= */ NULL, " "); continue; /* ask again */ case 'n': /* 'n' was removed in favor of 'f'. */ printf("Didn't understand 'n', did you mean 'f'?\n"); continue; /* ask again */ case 's': printf("Skipping execution.\n"); r = CONFIRM_PRETEND_SUCCESS; break; case 'y': r = CONFIRM_EXECUTE; break; default: assert_not_reached(); } break; } restore_stdio: restore_confirm_stdio(&saved_stdin, &saved_stdout); return r; } static int get_fixed_user(const ExecContext *c, const char **user, uid_t *uid, gid_t *gid, const char **home, const char **shell) { int r; const char *name; assert(c); if (!c->user) return 0; /* Note that we don't set $HOME or $SHELL if they are not particularly enlightening anyway * (i.e. are "/" or "/bin/nologin"). */ name = c->user; r = get_user_creds(&name, uid, gid, home, shell, USER_CREDS_CLEAN); if (r < 0) return r; *user = name; return 0; } static int get_fixed_group(const ExecContext *c, const char **group, gid_t *gid) { int r; const char *name; assert(c); if (!c->group) return 0; name = c->group; r = get_group_creds(&name, gid, 0); if (r < 0) return r; *group = name; return 0; } static int get_supplementary_groups(const ExecContext *c, const char *user, const char *group, gid_t gid, gid_t **supplementary_gids, int *ngids) { int r, k = 0; int ngroups_max; bool keep_groups = false; gid_t *groups = NULL; _cleanup_free_ gid_t *l_gids = NULL; assert(c); /* * If user is given, then lookup GID and supplementary groups list. * We avoid NSS lookups for gid=0. Also we have to initialize groups * here and as early as possible so we keep the list of supplementary * groups of the caller. */ if (user && gid_is_valid(gid) && gid != 0) { /* First step, initialize groups from /etc/groups */ if (initgroups(user, gid) < 0) return -errno; keep_groups = true; } if (strv_isempty(c->supplementary_groups)) return 0; /* * If SupplementaryGroups= was passed then NGROUPS_MAX has to * be positive, otherwise fail. */ errno = 0; ngroups_max = (int) sysconf(_SC_NGROUPS_MAX); if (ngroups_max <= 0) return errno_or_else(EOPNOTSUPP); l_gids = new(gid_t, ngroups_max); if (!l_gids) return -ENOMEM; if (keep_groups) { /* * Lookup the list of groups that the user belongs to, we * avoid NSS lookups here too for gid=0. */ k = ngroups_max; if (getgrouplist(user, gid, l_gids, &k) < 0) return -EINVAL; } else k = 0; STRV_FOREACH(i, c->supplementary_groups) { const char *g; if (k >= ngroups_max) return -E2BIG; g = *i; r = get_group_creds(&g, l_gids+k, 0); if (r < 0) return r; k++; } /* * Sets ngids to zero to drop all supplementary groups, happens * when we are under root and SupplementaryGroups= is empty. */ if (k == 0) { *ngids = 0; return 0; } /* Otherwise get the final list of supplementary groups */ groups = memdup(l_gids, sizeof(gid_t) * k); if (!groups) return -ENOMEM; *supplementary_gids = groups; *ngids = k; groups = NULL; return 0; } static int enforce_groups(gid_t gid, const gid_t *supplementary_gids, int ngids) { int r; /* Handle SupplementaryGroups= if it is not empty */ if (ngids > 0) { r = maybe_setgroups(ngids, supplementary_gids); if (r < 0) return r; } if (gid_is_valid(gid)) { /* Then set our gids */ if (setresgid(gid, gid, gid) < 0) return -errno; } return 0; } static int set_securebits(unsigned bits, unsigned mask) { unsigned applied; int current; current = prctl(PR_GET_SECUREBITS); if (current < 0) return -errno; /* Clear all securebits defined in mask and set bits */ applied = ((unsigned) current & ~mask) | bits; if ((unsigned) current == applied) return 0; if (prctl(PR_SET_SECUREBITS, applied) < 0) return -errno; return 1; } static int enforce_user( const ExecContext *context, uid_t uid, uint64_t capability_ambient_set) { assert(context); int r; if (!uid_is_valid(uid)) return 0; /* Sets (but doesn't look up) the UIS and makes sure we keep the capabilities while doing so. For * setting secure bits the capability CAP_SETPCAP is required, so we also need keep-caps in this * case. */ if ((capability_ambient_set != 0 || context->secure_bits != 0) && uid != 0) { /* First step: If we need to keep capabilities but drop privileges we need to make sure we * keep our caps, while we drop privileges. Add KEEP_CAPS to the securebits */ r = set_securebits(1U << SECURE_KEEP_CAPS, 0); if (r < 0) return r; } /* Second step: actually set the uids */ if (setresuid(uid, uid, uid) < 0) return -errno; /* At this point we should have all necessary capabilities but are otherwise a normal user. However, * the caps might got corrupted due to the setresuid() so we need clean them up later. This is done * outside of this call. */ return 0; } #if HAVE_PAM static int null_conv( int num_msg, const struct pam_message **msg, struct pam_response **resp, void *appdata_ptr) { /* We don't support conversations */ return PAM_CONV_ERR; } #endif static int setup_pam( const char *name, const char *user, uid_t uid, gid_t gid, const char *tty, char ***env, /* updated on success */ const int fds[], size_t n_fds) { #if HAVE_PAM static const struct pam_conv conv = { .conv = null_conv, .appdata_ptr = NULL }; _cleanup_(barrier_destroy) Barrier barrier = BARRIER_NULL; _cleanup_strv_free_ char **e = NULL; pam_handle_t *handle = NULL; sigset_t old_ss; int pam_code = PAM_SUCCESS, r; bool close_session = false; pid_t pam_pid = 0, parent_pid; int flags = 0; assert(name); assert(user); assert(env); /* We set up PAM in the parent process, then fork. The child * will then stay around until killed via PR_GET_PDEATHSIG or * systemd via the cgroup logic. It will then remove the PAM * session again. The parent process will exec() the actual * daemon. We do things this way to ensure that the main PID * of the daemon is the one we initially fork()ed. */ r = barrier_create(&barrier); if (r < 0) goto fail; if (log_get_max_level() < LOG_DEBUG) flags |= PAM_SILENT; pam_code = pam_start(name, user, &conv, &handle); if (pam_code != PAM_SUCCESS) { handle = NULL; goto fail; } if (!tty) { _cleanup_free_ char *q = NULL; /* Hmm, so no TTY was explicitly passed, but an fd passed to us directly might be a TTY. Let's figure * out if that's the case, and read the TTY off it. */ if (getttyname_malloc(STDIN_FILENO, &q) >= 0) tty = strjoina("/dev/", q); } if (tty) { pam_code = pam_set_item(handle, PAM_TTY, tty); if (pam_code != PAM_SUCCESS) goto fail; } STRV_FOREACH(nv, *env) { pam_code = pam_putenv(handle, *nv); if (pam_code != PAM_SUCCESS) goto fail; } pam_code = pam_acct_mgmt(handle, flags); if (pam_code != PAM_SUCCESS) goto fail; pam_code = pam_setcred(handle, PAM_ESTABLISH_CRED | flags); if (pam_code != PAM_SUCCESS) log_debug("pam_setcred() failed, ignoring: %s", pam_strerror(handle, pam_code)); pam_code = pam_open_session(handle, flags); if (pam_code != PAM_SUCCESS) goto fail; close_session = true; e = pam_getenvlist(handle); if (!e) { pam_code = PAM_BUF_ERR; goto fail; } /* Block SIGTERM, so that we know that it won't get lost in the child */ assert_se(sigprocmask_many(SIG_BLOCK, &old_ss, SIGTERM, -1) >= 0); parent_pid = getpid_cached(); r = safe_fork("(sd-pam)", 0, &pam_pid); if (r < 0) goto fail; if (r == 0) { int sig, ret = EXIT_PAM; /* The child's job is to reset the PAM session on termination */ barrier_set_role(&barrier, BARRIER_CHILD); /* Make sure we don't keep open the passed fds in this child. We assume that otherwise only * those fds are open here that have been opened by PAM. */ (void) close_many(fds, n_fds); /* Drop privileges - we don't need any to pam_close_session and this will make * PR_SET_PDEATHSIG work in most cases. If this fails, ignore the error - but expect sd-pam * threads to fail to exit normally */ r = maybe_setgroups(0, NULL); if (r < 0) log_warning_errno(r, "Failed to setgroups() in sd-pam: %m"); if (setresgid(gid, gid, gid) < 0) log_warning_errno(errno, "Failed to setresgid() in sd-pam: %m"); if (setresuid(uid, uid, uid) < 0) log_warning_errno(errno, "Failed to setresuid() in sd-pam: %m"); (void) ignore_signals(SIGPIPE); /* Wait until our parent died. This will only work if the above setresuid() succeeds, * otherwise the kernel will not allow unprivileged parents kill their privileged children * this way. We rely on the control groups kill logic to do the rest for us. */ if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) goto child_finish; /* Tell the parent that our setup is done. This is especially important regarding dropping * privileges. Otherwise, unit setup might race against our setresuid(2) call. * * If the parent aborted, we'll detect this below, hence ignore return failure here. */ (void) barrier_place(&barrier); /* Check if our parent process might already have died? */ if (getppid() == parent_pid) { sigset_t ss; assert_se(sigemptyset(&ss) >= 0); assert_se(sigaddset(&ss, SIGTERM) >= 0); for (;;) { if (sigwait(&ss, &sig) < 0) { if (errno == EINTR) continue; goto child_finish; } assert(sig == SIGTERM); break; } } pam_code = pam_setcred(handle, PAM_DELETE_CRED | flags); if (pam_code != PAM_SUCCESS) goto child_finish; /* If our parent died we'll end the session */ if (getppid() != parent_pid) { pam_code = pam_close_session(handle, flags); if (pam_code != PAM_SUCCESS) goto child_finish; } ret = 0; child_finish: /* NB: pam_end() when called in child processes should set PAM_DATA_SILENT to let the module * know about this. See pam_end(3) */ (void) pam_end(handle, pam_code | flags | PAM_DATA_SILENT); _exit(ret); } barrier_set_role(&barrier, BARRIER_PARENT); /* If the child was forked off successfully it will do all the cleanups, so forget about the handle * here. */ handle = NULL; /* Unblock SIGTERM again in the parent */ assert_se(sigprocmask(SIG_SETMASK, &old_ss, NULL) >= 0); /* We close the log explicitly here, since the PAM modules might have opened it, but we don't want * this fd around. */ closelog(); /* Synchronously wait for the child to initialize. We don't care for errors as we cannot * recover. However, warn loudly if it happens. */ if (!barrier_place_and_sync(&barrier)) log_error("PAM initialization failed"); return strv_free_and_replace(*env, e); fail: if (pam_code != PAM_SUCCESS) { log_error("PAM failed: %s", pam_strerror(handle, pam_code)); r = -EPERM; /* PAM errors do not map to errno */ } else log_error_errno(r, "PAM failed: %m"); if (handle) { if (close_session) pam_code = pam_close_session(handle, flags); (void) pam_end(handle, pam_code | flags); } closelog(); return r; #else return 0; #endif } static void rename_process_from_path(const char *path) { _cleanup_free_ char *buf = NULL; const char *p; assert(path); /* This resulting string must fit in 10 chars (i.e. the length of "/sbin/init") to look pretty in * /bin/ps */ if (path_extract_filename(path, &buf) < 0) { rename_process("(...)"); return; } size_t l = strlen(buf); if (l > 8) { /* The end of the process name is usually more interesting, since the first bit might just be * "systemd-" */ p = buf + l - 8; l = 8; } else p = buf; char process_name[11]; process_name[0] = '('; memcpy(process_name+1, p, l); process_name[1+l] = ')'; process_name[1+l+1] = 0; rename_process(process_name); } static bool context_has_address_families(const ExecContext *c) { assert(c); return c->address_families_allow_list || !set_isempty(c->address_families); } static bool context_has_syscall_filters(const ExecContext *c) { assert(c); return c->syscall_allow_list || !hashmap_isempty(c->syscall_filter); } static bool context_has_syscall_logs(const ExecContext *c) { assert(c); return c->syscall_log_allow_list || !hashmap_isempty(c->syscall_log); } static bool context_has_no_new_privileges(const ExecContext *c) { assert(c); if (c->no_new_privileges) return true; if (have_effective_cap(CAP_SYS_ADMIN) > 0) /* if we are privileged, we don't need NNP */ return false; /* We need NNP if we have any form of seccomp and are unprivileged */ return c->lock_personality || c->memory_deny_write_execute || c->private_devices || c->protect_clock || c->protect_hostname || c->protect_kernel_tunables || c->protect_kernel_modules || c->protect_kernel_logs || context_has_address_families(c) || exec_context_restrict_namespaces_set(c) || c->restrict_realtime || c->restrict_suid_sgid || !set_isempty(c->syscall_archs) || context_has_syscall_filters(c) || context_has_syscall_logs(c); } static bool exec_context_has_credentials(const ExecContext *context) { assert(context); return !hashmap_isempty(context->set_credentials) || !hashmap_isempty(context->load_credentials); } #if HAVE_SECCOMP static bool skip_seccomp_unavailable(const Unit* u, const char* msg) { if (is_seccomp_available()) return false; log_unit_debug(u, "SECCOMP features not detected in the kernel, skipping %s", msg); return true; } static int apply_syscall_filter(const Unit* u, const ExecContext *c, bool needs_ambient_hack) { uint32_t negative_action, default_action, action; int r; assert(u); assert(c); if (!context_has_syscall_filters(c)) return 0; if (skip_seccomp_unavailable(u, "SystemCallFilter=")) return 0; negative_action = c->syscall_errno == SECCOMP_ERROR_NUMBER_KILL ? scmp_act_kill_process() : SCMP_ACT_ERRNO(c->syscall_errno); if (c->syscall_allow_list) { default_action = negative_action; action = SCMP_ACT_ALLOW; } else { default_action = SCMP_ACT_ALLOW; action = negative_action; } if (needs_ambient_hack) { r = seccomp_filter_set_add(c->syscall_filter, c->syscall_allow_list, syscall_filter_sets + SYSCALL_FILTER_SET_SETUID); if (r < 0) return r; } return seccomp_load_syscall_filter_set_raw(default_action, c->syscall_filter, action, false); } static int apply_syscall_log(const Unit* u, const ExecContext *c) { #ifdef SCMP_ACT_LOG uint32_t default_action, action; #endif assert(u); assert(c); if (!context_has_syscall_logs(c)) return 0; #ifdef SCMP_ACT_LOG if (skip_seccomp_unavailable(u, "SystemCallLog=")) return 0; if (c->syscall_log_allow_list) { /* Log nothing but the ones listed */ default_action = SCMP_ACT_ALLOW; action = SCMP_ACT_LOG; } else { /* Log everything but the ones listed */ default_action = SCMP_ACT_LOG; action = SCMP_ACT_ALLOW; } return seccomp_load_syscall_filter_set_raw(default_action, c->syscall_log, action, false); #else /* old libseccomp */ log_unit_debug(u, "SECCOMP feature SCMP_ACT_LOG not available, skipping SystemCallLog="); return 0; #endif } static int apply_syscall_archs(const Unit *u, const ExecContext *c) { assert(u); assert(c); if (set_isempty(c->syscall_archs)) return 0; if (skip_seccomp_unavailable(u, "SystemCallArchitectures=")) return 0; return seccomp_restrict_archs(c->syscall_archs); } static int apply_address_families(const Unit* u, const ExecContext *c) { assert(u); assert(c); if (!context_has_address_families(c)) return 0; if (skip_seccomp_unavailable(u, "RestrictAddressFamilies=")) return 0; return seccomp_restrict_address_families(c->address_families, c->address_families_allow_list); } static int apply_memory_deny_write_execute(const Unit* u, const ExecContext *c) { int r; assert(u); assert(c); if (!c->memory_deny_write_execute) return 0; /* use prctl() if kernel supports it (6.3) */ r = prctl(PR_SET_MDWE, PR_MDWE_REFUSE_EXEC_GAIN, 0, 0, 0); if (r == 0) { log_unit_debug(u, "Enabled MemoryDenyWriteExecute= with PR_SET_MDWE"); return 0; } if (r < 0 && errno != EINVAL) return log_unit_debug_errno(u, errno, "Failed to enable MemoryDenyWriteExecute= with PR_SET_MDWE: %m"); /* else use seccomp */ log_unit_debug(u, "Kernel doesn't support PR_SET_MDWE: falling back to seccomp"); if (skip_seccomp_unavailable(u, "MemoryDenyWriteExecute=")) return 0; return seccomp_memory_deny_write_execute(); } static int apply_restrict_realtime(const Unit* u, const ExecContext *c) { assert(u); assert(c); if (!c->restrict_realtime) return 0; if (skip_seccomp_unavailable(u, "RestrictRealtime=")) return 0; return seccomp_restrict_realtime(); } static int apply_restrict_suid_sgid(const Unit* u, const ExecContext *c) { assert(u); assert(c); if (!c->restrict_suid_sgid) return 0; if (skip_seccomp_unavailable(u, "RestrictSUIDSGID=")) return 0; return seccomp_restrict_suid_sgid(); } static int apply_protect_sysctl(const Unit *u, const ExecContext *c) { assert(u); assert(c); /* Turn off the legacy sysctl() system call. Many distributions turn this off while building the kernel, but * let's protect even those systems where this is left on in the kernel. */ if (!c->protect_kernel_tunables) return 0; if (skip_seccomp_unavailable(u, "ProtectKernelTunables=")) return 0; return seccomp_protect_sysctl(); } static int apply_protect_kernel_modules(const Unit *u, const ExecContext *c) { assert(u); assert(c); /* Turn off module syscalls on ProtectKernelModules=yes */ if (!c->protect_kernel_modules) return 0; if (skip_seccomp_unavailable(u, "ProtectKernelModules=")) return 0; return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_MODULE, SCMP_ACT_ERRNO(EPERM), false); } static int apply_protect_kernel_logs(const Unit *u, const ExecContext *c) { assert(u); assert(c); if (!c->protect_kernel_logs) return 0; if (skip_seccomp_unavailable(u, "ProtectKernelLogs=")) return 0; return seccomp_protect_syslog(); } static int apply_protect_clock(const Unit *u, const ExecContext *c) { assert(u); assert(c); if (!c->protect_clock) return 0; if (skip_seccomp_unavailable(u, "ProtectClock=")) return 0; return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_CLOCK, SCMP_ACT_ERRNO(EPERM), false); } static int apply_private_devices(const Unit *u, const ExecContext *c) { assert(u); assert(c); /* If PrivateDevices= is set, also turn off iopl and all @raw-io syscalls. */ if (!c->private_devices) return 0; if (skip_seccomp_unavailable(u, "PrivateDevices=")) return 0; return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO, SCMP_ACT_ERRNO(EPERM), false); } static int apply_restrict_namespaces(const Unit *u, const ExecContext *c) { assert(u); assert(c); if (!exec_context_restrict_namespaces_set(c)) return 0; if (skip_seccomp_unavailable(u, "RestrictNamespaces=")) return 0; return seccomp_restrict_namespaces(c->restrict_namespaces); } static int apply_lock_personality(const Unit* u, const ExecContext *c) { unsigned long personality; int r; assert(u); assert(c); if (!c->lock_personality) return 0; if (skip_seccomp_unavailable(u, "LockPersonality=")) return 0; personality = c->personality; /* If personality is not specified, use either PER_LINUX or PER_LINUX32 depending on what is currently set. */ if (personality == PERSONALITY_INVALID) { r = opinionated_personality(&personality); if (r < 0) return r; } return seccomp_lock_personality(personality); } #endif #if HAVE_LIBBPF static int apply_restrict_filesystems(Unit *u, const ExecContext *c) { assert(u); assert(c); if (!exec_context_restrict_filesystems_set(c)) return 0; if (!u->manager->restrict_fs) { /* LSM BPF is unsupported or lsm_bpf_setup failed */ log_unit_debug(u, "LSM BPF not supported, skipping RestrictFileSystems="); return 0; } return lsm_bpf_unit_restrict_filesystems(u, c->restrict_filesystems, c->restrict_filesystems_allow_list); } #endif static int apply_protect_hostname(const Unit *u, const ExecContext *c, int *ret_exit_status) { assert(u); assert(c); if (!c->protect_hostname) return 0; if (ns_type_supported(NAMESPACE_UTS)) { if (unshare(CLONE_NEWUTS) < 0) { if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno)) { *ret_exit_status = EXIT_NAMESPACE; return log_unit_error_errno(u, errno, "Failed to set up UTS namespacing: %m"); } log_unit_warning(u, "ProtectHostname=yes is configured, but UTS namespace setup is prohibited (container manager?), ignoring namespace setup."); } } else log_unit_warning(u, "ProtectHostname=yes is configured, but the kernel does not support UTS namespaces, ignoring namespace setup."); #if HAVE_SECCOMP int r; if (skip_seccomp_unavailable(u, "ProtectHostname=")) return 0; r = seccomp_protect_hostname(); if (r < 0) { *ret_exit_status = EXIT_SECCOMP; return log_unit_error_errno(u, r, "Failed to apply hostname restrictions: %m"); } #endif return 0; } static void do_idle_pipe_dance(int idle_pipe[static 4]) { assert(idle_pipe); idle_pipe[1] = safe_close(idle_pipe[1]); idle_pipe[2] = safe_close(idle_pipe[2]); if (idle_pipe[0] >= 0) { int r; r = fd_wait_for_event(idle_pipe[0], POLLHUP, IDLE_TIMEOUT_USEC); if (idle_pipe[3] >= 0 && r == 0 /* timeout */) { ssize_t n; /* Signal systemd that we are bored and want to continue. */ n = write(idle_pipe[3], "x", 1); if (n > 0) /* Wait for systemd to react to the signal above. */ (void) fd_wait_for_event(idle_pipe[0], POLLHUP, IDLE_TIMEOUT2_USEC); } idle_pipe[0] = safe_close(idle_pipe[0]); } idle_pipe[3] = safe_close(idle_pipe[3]); } static const char *exec_directory_env_name_to_string(ExecDirectoryType t); static int build_environment( const Unit *u, const ExecContext *c, const ExecParameters *p, const CGroupContext *cgroup_context, size_t n_fds, char **fdnames, const char *home, const char *username, const char *shell, dev_t journal_stream_dev, ino_t journal_stream_ino, const char *memory_pressure_path, char ***ret) { _cleanup_strv_free_ char **our_env = NULL; size_t n_env = 0; char *x; int r; assert(u); assert(c); assert(p); assert(ret); #define N_ENV_VARS 19 our_env = new0(char*, N_ENV_VARS + _EXEC_DIRECTORY_TYPE_MAX); if (!our_env) return -ENOMEM; if (n_fds > 0) { _cleanup_free_ char *joined = NULL; if (asprintf(&x, "LISTEN_PID="PID_FMT, getpid_cached()) < 0) return -ENOMEM; our_env[n_env++] = x; if (asprintf(&x, "LISTEN_FDS=%zu", n_fds) < 0) return -ENOMEM; our_env[n_env++] = x; joined = strv_join(fdnames, ":"); if (!joined) return -ENOMEM; x = strjoin("LISTEN_FDNAMES=", joined); if (!x) return -ENOMEM; our_env[n_env++] = x; } if ((p->flags & EXEC_SET_WATCHDOG) && p->watchdog_usec > 0) { if (asprintf(&x, "WATCHDOG_PID="PID_FMT, getpid_cached()) < 0) return -ENOMEM; our_env[n_env++] = x; if (asprintf(&x, "WATCHDOG_USEC="USEC_FMT, p->watchdog_usec) < 0) return -ENOMEM; our_env[n_env++] = x; } /* If this is D-Bus, tell the nss-systemd module, since it relies on being able to use blocking * Varlink calls back to us for look up dynamic users in PID 1. Break the deadlock between D-Bus and * PID 1 by disabling use of PID1' NSS interface for looking up dynamic users. */ if (p->flags & EXEC_NSS_DYNAMIC_BYPASS) { x = strdup("SYSTEMD_NSS_DYNAMIC_BYPASS=1"); if (!x) return -ENOMEM; our_env[n_env++] = x; } if (home) { x = strjoin("HOME=", home); if (!x) return -ENOMEM; path_simplify(x + 5); our_env[n_env++] = x; } if (username) { x = strjoin("LOGNAME=", username); if (!x) return -ENOMEM; our_env[n_env++] = x; x = strjoin("USER=", username); if (!x) return -ENOMEM; our_env[n_env++] = x; } if (shell) { x = strjoin("SHELL=", shell); if (!x) return -ENOMEM; path_simplify(x + 6); our_env[n_env++] = x; } if (!sd_id128_is_null(u->invocation_id)) { if (asprintf(&x, "INVOCATION_ID=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(u->invocation_id)) < 0) return -ENOMEM; our_env[n_env++] = x; } if (exec_context_needs_term(c)) { _cleanup_free_ char *cmdline = NULL; const char *tty_path, *term = NULL; tty_path = exec_context_tty_path(c); /* If we are forked off PID 1 and we are supposed to operate on /dev/console, then let's try * to inherit the $TERM set for PID 1. This is useful for containers so that the $TERM the * container manager passes to PID 1 ends up all the way in the console login shown. */ if (path_equal_ptr(tty_path, "/dev/console") && getppid() == 1) term = getenv("TERM"); else if (tty_path && in_charset(skip_dev_prefix(tty_path), ALPHANUMERICAL)) { _cleanup_free_ char *key = NULL; key = strjoin("systemd.tty.term.", skip_dev_prefix(tty_path)); if (!key) return -ENOMEM; r = proc_cmdline_get_key(key, 0, &cmdline); if (r < 0) log_debug_errno(r, "Failed to read %s from kernel cmdline, ignoring: %m", key); else if (r > 0) term = cmdline; } if (!term) term = default_term_for_tty(tty_path); x = strjoin("TERM=", term); if (!x) return -ENOMEM; our_env[n_env++] = x; } if (journal_stream_dev != 0 && journal_stream_ino != 0) { if (asprintf(&x, "JOURNAL_STREAM=" DEV_FMT ":" INO_FMT, journal_stream_dev, journal_stream_ino) < 0) return -ENOMEM; our_env[n_env++] = x; } if (c->log_namespace) { x = strjoin("LOG_NAMESPACE=", c->log_namespace); if (!x) return -ENOMEM; our_env[n_env++] = x; } for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) { _cleanup_free_ char *joined = NULL; const char *n; if (!p->prefix[t]) continue; if (c->directories[t].n_items == 0) continue; n = exec_directory_env_name_to_string(t); if (!n) continue; for (size_t i = 0; i < c->directories[t].n_items; i++) { _cleanup_free_ char *prefixed = NULL; prefixed = path_join(p->prefix[t], c->directories[t].items[i].path); if (!prefixed) return -ENOMEM; if (!strextend_with_separator(&joined, ":", prefixed)) return -ENOMEM; } x = strjoin(n, "=", joined); if (!x) return -ENOMEM; our_env[n_env++] = x; } if (exec_context_has_credentials(c) && p->prefix[EXEC_DIRECTORY_RUNTIME]) { x = strjoin("CREDENTIALS_DIRECTORY=", p->prefix[EXEC_DIRECTORY_RUNTIME], "/credentials/", u->id); if (!x) return -ENOMEM; our_env[n_env++] = x; } if (asprintf(&x, "SYSTEMD_EXEC_PID=" PID_FMT, getpid_cached()) < 0) return -ENOMEM; our_env[n_env++] = x; if (memory_pressure_path) { x = strjoin("MEMORY_PRESSURE_WATCH=", memory_pressure_path); if (!x) return -ENOMEM; our_env[n_env++] = x; if (cgroup_context && !path_equal(memory_pressure_path, "/dev/null")) { _cleanup_free_ char *b = NULL, *e = NULL; if (asprintf(&b, "%s " USEC_FMT " " USEC_FMT, MEMORY_PRESSURE_DEFAULT_TYPE, cgroup_context->memory_pressure_threshold_usec == USEC_INFINITY ? MEMORY_PRESSURE_DEFAULT_THRESHOLD_USEC : CLAMP(cgroup_context->memory_pressure_threshold_usec, 1U, MEMORY_PRESSURE_DEFAULT_WINDOW_USEC), MEMORY_PRESSURE_DEFAULT_WINDOW_USEC) < 0) return -ENOMEM; if (base64mem(b, strlen(b) + 1, &e) < 0) return -ENOMEM; x = strjoin("MEMORY_PRESSURE_WRITE=", e); if (!x) return -ENOMEM; our_env[n_env++] = x; } } assert(n_env < N_ENV_VARS + _EXEC_DIRECTORY_TYPE_MAX); #undef N_ENV_VARS *ret = TAKE_PTR(our_env); return 0; } static int build_pass_environment(const ExecContext *c, char ***ret) { _cleanup_strv_free_ char **pass_env = NULL; size_t n_env = 0; STRV_FOREACH(i, c->pass_environment) { _cleanup_free_ char *x = NULL; char *v; v = getenv(*i); if (!v) continue; x = strjoin(*i, "=", v); if (!x) return -ENOMEM; if (!GREEDY_REALLOC(pass_env, n_env + 2)) return -ENOMEM; pass_env[n_env++] = TAKE_PTR(x); pass_env[n_env] = NULL; } *ret = TAKE_PTR(pass_env); return 0; } bool exec_needs_network_namespace(const ExecContext *context) { assert(context); return context->private_network || context->network_namespace_path; } static bool exec_needs_ipc_namespace(const ExecContext *context) { assert(context); return context->private_ipc || context->ipc_namespace_path; } bool exec_needs_mount_namespace( const ExecContext *context, const ExecParameters *params, const ExecRuntime *runtime) { assert(context); if (context->root_image) return true; if (!strv_isempty(context->read_write_paths) || !strv_isempty(context->read_only_paths) || !strv_isempty(context->inaccessible_paths) || !strv_isempty(context->exec_paths) || !strv_isempty(context->no_exec_paths)) return true; if (context->n_bind_mounts > 0) return true; if (context->n_temporary_filesystems > 0) return true; if (context->n_mount_images > 0) return true; if (context->n_extension_images > 0) return true; if (!strv_isempty(context->extension_directories)) return true; if (!IN_SET(context->mount_propagation_flag, 0, MS_SHARED)) return true; if (context->private_tmp && runtime && runtime->shared && (runtime->shared->tmp_dir || runtime->shared->var_tmp_dir)) return true; if (context->private_devices || context->private_mounts > 0 || (context->private_mounts < 0 && exec_needs_network_namespace(context)) || context->protect_system != PROTECT_SYSTEM_NO || context->protect_home != PROTECT_HOME_NO || context->protect_kernel_tunables || context->protect_kernel_modules || context->protect_kernel_logs || context->protect_control_groups || context->protect_proc != PROTECT_PROC_DEFAULT || context->proc_subset != PROC_SUBSET_ALL || exec_needs_ipc_namespace(context)) return true; if (context->root_directory) { if (exec_context_get_effective_mount_apivfs(context)) return true; for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) { if (params && !params->prefix[t]) continue; if (context->directories[t].n_items > 0) return true; } } if (context->dynamic_user && (context->directories[EXEC_DIRECTORY_STATE].n_items > 0 || context->directories[EXEC_DIRECTORY_CACHE].n_items > 0 || context->directories[EXEC_DIRECTORY_LOGS].n_items > 0)) return true; if (context->log_namespace) return true; return false; } static int setup_private_users(uid_t ouid, gid_t ogid, uid_t uid, gid_t gid) { _cleanup_free_ char *uid_map = NULL, *gid_map = NULL; _cleanup_close_pair_ int errno_pipe[2] = PIPE_EBADF; _cleanup_close_ int unshare_ready_fd = -EBADF; _cleanup_(sigkill_waitp) pid_t pid = 0; uint64_t c = 1; ssize_t n; int r; /* Set up a user namespace and map the original UID/GID (IDs from before any user or group changes, i.e. * the IDs from the user or system manager(s)) to itself, the selected UID/GID to itself, and everything else to * nobody. In order to be able to write this mapping we need CAP_SETUID in the original user namespace, which * we however lack after opening the user namespace. To work around this we fork() a temporary child process, * which waits for the parent to create the new user namespace while staying in the original namespace. The * child then writes the UID mapping, under full privileges. The parent waits for the child to finish and * continues execution normally. * For unprivileged users (i.e. without capabilities), the root to root mapping is excluded. As such, it * does not need CAP_SETUID to write the single line mapping to itself. */ /* Can only set up multiple mappings with CAP_SETUID. */ if (have_effective_cap(CAP_SETUID) > 0 && uid != ouid && uid_is_valid(uid)) r = asprintf(&uid_map, UID_FMT " " UID_FMT " 1\n" /* Map $OUID → $OUID */ UID_FMT " " UID_FMT " 1\n", /* Map $UID → $UID */ ouid, ouid, uid, uid); else r = asprintf(&uid_map, UID_FMT " " UID_FMT " 1\n", /* Map $OUID → $OUID */ ouid, ouid); if (r < 0) return -ENOMEM; /* Can only set up multiple mappings with CAP_SETGID. */ if (have_effective_cap(CAP_SETGID) > 0 && gid != ogid && gid_is_valid(gid)) r = asprintf(&gid_map, GID_FMT " " GID_FMT " 1\n" /* Map $OGID → $OGID */ GID_FMT " " GID_FMT " 1\n", /* Map $GID → $GID */ ogid, ogid, gid, gid); else r = asprintf(&gid_map, GID_FMT " " GID_FMT " 1\n", /* Map $OGID -> $OGID */ ogid, ogid); if (r < 0) return -ENOMEM; /* Create a communication channel so that the parent can tell the child when it finished creating the user * namespace. */ unshare_ready_fd = eventfd(0, EFD_CLOEXEC); if (unshare_ready_fd < 0) return -errno; /* Create a communication channel so that the child can tell the parent a proper error code in case it * failed. */ if (pipe2(errno_pipe, O_CLOEXEC) < 0) return -errno; r = safe_fork("(sd-userns)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &pid); if (r < 0) return r; if (r == 0) { _cleanup_close_ int fd = -EBADF; const char *a; pid_t ppid; /* Child process, running in the original user namespace. Let's update the parent's UID/GID map from * here, after the parent opened its own user namespace. */ ppid = getppid(); errno_pipe[0] = safe_close(errno_pipe[0]); /* Wait until the parent unshared the user namespace */ if (read(unshare_ready_fd, &c, sizeof(c)) < 0) { r = -errno; goto child_fail; } /* Disable the setgroups() system call in the child user namespace, for good. */ a = procfs_file_alloca(ppid, "setgroups"); fd = open(a, O_WRONLY|O_CLOEXEC); if (fd < 0) { if (errno != ENOENT) { r = -errno; goto child_fail; } /* If the file is missing the kernel is too old, let's continue anyway. */ } else { if (write(fd, "deny\n", 5) < 0) { r = -errno; goto child_fail; } fd = safe_close(fd); } /* First write the GID map */ a = procfs_file_alloca(ppid, "gid_map"); fd = open(a, O_WRONLY|O_CLOEXEC); if (fd < 0) { r = -errno; goto child_fail; } if (write(fd, gid_map, strlen(gid_map)) < 0) { r = -errno; goto child_fail; } fd = safe_close(fd); /* The write the UID map */ a = procfs_file_alloca(ppid, "uid_map"); fd = open(a, O_WRONLY|O_CLOEXEC); if (fd < 0) { r = -errno; goto child_fail; } if (write(fd, uid_map, strlen(uid_map)) < 0) { r = -errno; goto child_fail; } _exit(EXIT_SUCCESS); child_fail: (void) write(errno_pipe[1], &r, sizeof(r)); _exit(EXIT_FAILURE); } errno_pipe[1] = safe_close(errno_pipe[1]); if (unshare(CLONE_NEWUSER) < 0) return -errno; /* Let the child know that the namespace is ready now */ if (write(unshare_ready_fd, &c, sizeof(c)) < 0) return -errno; /* Try to read an error code from the child */ n = read(errno_pipe[0], &r, sizeof(r)); if (n < 0) return -errno; if (n == sizeof(r)) { /* an error code was sent to us */ if (r < 0) return r; return -EIO; } if (n != 0) /* on success we should have read 0 bytes */ return -EIO; r = wait_for_terminate_and_check("(sd-userns)", TAKE_PID(pid), 0); if (r < 0) return r; if (r != EXIT_SUCCESS) /* If something strange happened with the child, let's consider this fatal, too */ return -EIO; return 0; } static bool exec_directory_is_private(const ExecContext *context, ExecDirectoryType type) { assert(context); if (!context->dynamic_user) return false; if (type == EXEC_DIRECTORY_CONFIGURATION) return false; if (type == EXEC_DIRECTORY_RUNTIME && context->runtime_directory_preserve_mode == EXEC_PRESERVE_NO) return false; return true; } static int create_many_symlinks(const char *root, const char *source, char **symlinks) { _cleanup_free_ char *src_abs = NULL; int r; assert(source); src_abs = path_join(root, source); if (!src_abs) return -ENOMEM; STRV_FOREACH(dst, symlinks) { _cleanup_free_ char *dst_abs = NULL; dst_abs = path_join(root, *dst); if (!dst_abs) return -ENOMEM; r = mkdir_parents_label(dst_abs, 0755); if (r < 0) return r; r = symlink_idempotent(src_abs, dst_abs, true); if (r < 0) return r; } return 0; } static int setup_exec_directory( const ExecContext *context, const ExecParameters *params, uid_t uid, gid_t gid, ExecDirectoryType type, bool needs_mount_namespace, int *exit_status) { static const int exit_status_table[_EXEC_DIRECTORY_TYPE_MAX] = { [EXEC_DIRECTORY_RUNTIME] = EXIT_RUNTIME_DIRECTORY, [EXEC_DIRECTORY_STATE] = EXIT_STATE_DIRECTORY, [EXEC_DIRECTORY_CACHE] = EXIT_CACHE_DIRECTORY, [EXEC_DIRECTORY_LOGS] = EXIT_LOGS_DIRECTORY, [EXEC_DIRECTORY_CONFIGURATION] = EXIT_CONFIGURATION_DIRECTORY, }; int r; assert(context); assert(params); assert(type >= 0 && type < _EXEC_DIRECTORY_TYPE_MAX); assert(exit_status); if (!params->prefix[type]) return 0; if (params->flags & EXEC_CHOWN_DIRECTORIES) { if (!uid_is_valid(uid)) uid = 0; if (!gid_is_valid(gid)) gid = 0; } for (size_t i = 0; i < context->directories[type].n_items; i++) { _cleanup_free_ char *p = NULL, *pp = NULL; p = path_join(params->prefix[type], context->directories[type].items[i].path); if (!p) { r = -ENOMEM; goto fail; } r = mkdir_parents_label(p, 0755); if (r < 0) goto fail; if (exec_directory_is_private(context, type)) { /* So, here's one extra complication when dealing with DynamicUser=1 units. In that * case we want to avoid leaving a directory around fully accessible that is owned by * a dynamic user whose UID is later on reused. To lock this down we use the same * trick used by container managers to prohibit host users to get access to files of * the same UID in containers: we place everything inside a directory that has an * access mode of 0700 and is owned root:root, so that it acts as security boundary * for unprivileged host code. We then use fs namespacing to make this directory * permeable for the service itself. * * Specifically: for a service which wants a special directory "foo/" we first create * a directory "private/" with access mode 0700 owned by root:root. Then we place * "foo" inside of that directory (i.e. "private/foo/"), and make "foo" a symlink to * "private/foo". This way, privileged host users can access "foo/" as usual, but * unprivileged host users can't look into it. Inside of the namespace of the unit * "private/" is replaced by a more liberally accessible tmpfs, into which the host's * "private/foo/" is mounted under the same name, thus disabling the access boundary * for the service and making sure it only gets access to the dirs it needs but no * others. Tricky? Yes, absolutely, but it works! * * Note that we don't do this for EXEC_DIRECTORY_CONFIGURATION as that's assumed not * to be owned by the service itself. * * Also, note that we don't do this for EXEC_DIRECTORY_RUNTIME as that's often used * for sharing files or sockets with other services. */ pp = path_join(params->prefix[type], "private"); if (!pp) { r = -ENOMEM; goto fail; } /* First set up private root if it doesn't exist yet, with access mode 0700 and owned by root:root */ r = mkdir_safe_label(pp, 0700, 0, 0, MKDIR_WARN_MODE); if (r < 0) goto fail; if (!path_extend(&pp, context->directories[type].items[i].path)) { r = -ENOMEM; goto fail; } /* Create all directories between the configured directory and this private root, and mark them 0755 */ r = mkdir_parents_label(pp, 0755); if (r < 0) goto fail; if (is_dir(p, false) > 0 && (laccess(pp, F_OK) < 0 && errno == ENOENT)) { /* Hmm, the private directory doesn't exist yet, but the normal one exists? If so, move * it over. Most likely the service has been upgraded from one that didn't use * DynamicUser=1, to one that does. */ log_info("Found pre-existing public %s= directory %s, migrating to %s.\n" "Apparently, service previously had DynamicUser= turned off, and has now turned it on.", exec_directory_type_to_string(type), p, pp); if (rename(p, pp) < 0) { r = -errno; goto fail; } } else { /* Otherwise, create the actual directory for the service */ r = mkdir_label(pp, context->directories[type].mode); if (r < 0 && r != -EEXIST) goto fail; } if (!context->directories[type].items[i].only_create) { /* And link it up from the original place. * Notes * 1) If a mount namespace is going to be used, then this symlink remains on * the host, and a new one for the child namespace will be created later. * 2) It is not necessary to create this symlink when one of its parent * directories is specified and already created. E.g. * StateDirectory=foo foo/bar * In that case, the inode points to pp and p for "foo/bar" are the same: * pp = "/var/lib/private/foo/bar" * p = "/var/lib/foo/bar" * and, /var/lib/foo is a symlink to /var/lib/private/foo. So, not only * we do not need to create the symlink, but we cannot create the symlink. * See issue #24783. */ r = symlink_idempotent(pp, p, true); if (r < 0) goto fail; } } else { _cleanup_free_ char *target = NULL; if (type != EXEC_DIRECTORY_CONFIGURATION && readlink_and_make_absolute(p, &target) >= 0) { _cleanup_free_ char *q = NULL, *q_resolved = NULL, *target_resolved = NULL; /* This already exists and is a symlink? Interesting. Maybe it's one created * by DynamicUser=1 (see above)? * * We do this for all directory types except for ConfigurationDirectory=, * since they all support the private/ symlink logic at least in some * configurations, see above. */ r = chase(target, NULL, 0, &target_resolved, NULL); if (r < 0) goto fail; q = path_join(params->prefix[type], "private", context->directories[type].items[i].path); if (!q) { r = -ENOMEM; goto fail; } /* /var/lib or friends may be symlinks. So, let's chase them also. */ r = chase(q, NULL, CHASE_NONEXISTENT, &q_resolved, NULL); if (r < 0) goto fail; if (path_equal(q_resolved, target_resolved)) { /* Hmm, apparently DynamicUser= was once turned on for this service, * but is no longer. Let's move the directory back up. */ log_info("Found pre-existing private %s= directory %s, migrating to %s.\n" "Apparently, service previously had DynamicUser= turned on, and has now turned it off.", exec_directory_type_to_string(type), q, p); if (unlink(p) < 0) { r = -errno; goto fail; } if (rename(q, p) < 0) { r = -errno; goto fail; } } } r = mkdir_label(p, context->directories[type].mode); if (r < 0) { if (r != -EEXIST) goto fail; if (type == EXEC_DIRECTORY_CONFIGURATION) { struct stat st; /* Don't change the owner/access mode of the configuration directory, * as in the common case it is not written to by a service, and shall * not be writable. */ if (stat(p, &st) < 0) { r = -errno; goto fail; } /* Still complain if the access mode doesn't match */ if (((st.st_mode ^ context->directories[type].mode) & 07777) != 0) log_warning("%s \'%s\' already exists but the mode is different. " "(File system: %o %sMode: %o)", exec_directory_type_to_string(type), context->directories[type].items[i].path, st.st_mode & 07777, exec_directory_type_to_string(type), context->directories[type].mode & 07777); continue; } } } /* Lock down the access mode (we use chmod_and_chown() to make this idempotent. We don't * specify UID/GID here, so that path_chown_recursive() can optimize things depending on the * current UID/GID ownership.) */ r = chmod_and_chown(pp ?: p, context->directories[type].mode, UID_INVALID, GID_INVALID); if (r < 0) goto fail; /* Then, change the ownership of the whole tree, if necessary. When dynamic users are used we * drop the suid/sgid bits, since we really don't want SUID/SGID files for dynamic UID/GID * assignments to exist. */ r = path_chown_recursive(pp ?: p, uid, gid, context->dynamic_user ? 01777 : 07777); if (r < 0) goto fail; } /* If we are not going to run in a namespace, set up the symlinks - otherwise * they are set up later, to allow configuring empty var/run/etc. */ if (!needs_mount_namespace) for (size_t i = 0; i < context->directories[type].n_items; i++) { r = create_many_symlinks(params->prefix[type], context->directories[type].items[i].path, context->directories[type].items[i].symlinks); if (r < 0) goto fail; } return 0; fail: *exit_status = exit_status_table[type]; return r; } static int write_credential( int dfd, const char *id, const void *data, size_t size, uid_t uid, bool ownership_ok) { _cleanup_(unlink_and_freep) char *tmp = NULL; _cleanup_close_ int fd = -EBADF; int r; r = tempfn_random_child("", "cred", &tmp); if (r < 0) return r; fd = openat(dfd, tmp, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL|O_NOFOLLOW|O_NOCTTY, 0600); if (fd < 0) { tmp = mfree(tmp); return -errno; } r = loop_write(fd, data, size, /* do_poll = */ false); if (r < 0) return r; if (fchmod(fd, 0400) < 0) /* Take away "w" bit */ return -errno; if (uid_is_valid(uid) && uid != getuid()) { r = fd_add_uid_acl_permission(fd, uid, ACL_READ); if (r < 0) { if (!ERRNO_IS_NOT_SUPPORTED(r) && !ERRNO_IS_PRIVILEGE(r)) return r; if (!ownership_ok) /* Ideally we use ACLs, since we can neatly express what we want * to express: that the user gets read access and nothing * else. But if the backing fs can't support that (e.g. ramfs) * then we can use file ownership instead. But that's only safe if * we can then re-mount the whole thing read-only, so that the * user can no longer chmod() the file to gain write access. */ return r; if (fchown(fd, uid, GID_INVALID) < 0) return -errno; } } if (renameat(dfd, tmp, dfd, id) < 0) return -errno; tmp = mfree(tmp); return 0; } static char **credential_search_path( const ExecParameters *params, bool encrypted) { _cleanup_strv_free_ char **l = NULL; assert(params); /* Assemble a search path to find credentials in. We'll look in /etc/credstore/ (and similar * directories in /usr/lib/ + /run/) for all types of credentials. If we are looking for encrypted * credentials, also look in /etc/credstore.encrypted/ (and similar dirs). */ if (encrypted) { if (strv_extend(&l, params->received_encrypted_credentials_directory) < 0) return NULL; if (strv_extend_strv(&l, CONF_PATHS_STRV("credstore.encrypted"), /* filter_duplicates= */ true) < 0) return NULL; } if (params->received_credentials_directory) if (strv_extend(&l, params->received_credentials_directory) < 0) return NULL; if (strv_extend_strv(&l, CONF_PATHS_STRV("credstore"), /* filter_duplicates= */ true) < 0) return NULL; if (DEBUG_LOGGING) { _cleanup_free_ char *t = strv_join(l, ":"); log_debug("Credential search path is: %s", t); } return TAKE_PTR(l); } static int load_credential( const ExecContext *context, const ExecParameters *params, const char *id, const char *path, bool encrypted, const char *unit, int read_dfd, int write_dfd, uid_t uid, bool ownership_ok, uint64_t *left) { ReadFullFileFlags flags = READ_FULL_FILE_SECURE|READ_FULL_FILE_FAIL_WHEN_LARGER; _cleanup_strv_free_ char **search_path = NULL; _cleanup_(erase_and_freep) char *data = NULL; _cleanup_free_ char *bindname = NULL; const char *source = NULL; bool missing_ok = true; size_t size, add, maxsz; int r; assert(context); assert(params); assert(id); assert(path); assert(unit); assert(read_dfd >= 0 || read_dfd == AT_FDCWD); assert(write_dfd >= 0); assert(left); if (read_dfd >= 0) { /* If a directory fd is specified, then read the file directly from that dir. In this case we * won't do AF_UNIX stuff (we simply don't want to recursively iterate down a tree of AF_UNIX * IPC sockets). It's OK if a file vanishes here in the time we enumerate it and intend to * open it. */ if (!filename_is_valid(path)) /* safety check */ return -EINVAL; missing_ok = true; source = path; } else if (path_is_absolute(path)) { /* If this is an absolute path, read the data directly from it, and support AF_UNIX * sockets */ if (!path_is_valid(path)) /* safety check */ return -EINVAL; flags |= READ_FULL_FILE_CONNECT_SOCKET; /* Pass some minimal info about the unit and the credential name we are looking to acquire * via the source socket address in case we read off an AF_UNIX socket. */ if (asprintf(&bindname, "@%" PRIx64"/unit/%s/%s", random_u64(), unit, id) < 0) return -ENOMEM; missing_ok = false; source = path; } else if (credential_name_valid(path)) { /* If this is a relative path, take it as credential name relative to the credentials * directory we received ourselves. We don't support the AF_UNIX stuff in this mode, since we * are operating on a credential store, i.e. this is guaranteed to be regular files. */ search_path = credential_search_path(params, encrypted); if (!search_path) return -ENOMEM; missing_ok = true; } else source = NULL; if (encrypted) flags |= READ_FULL_FILE_UNBASE64; maxsz = encrypted ? CREDENTIAL_ENCRYPTED_SIZE_MAX : CREDENTIAL_SIZE_MAX; if (search_path) { STRV_FOREACH(d, search_path) { _cleanup_free_ char *j = NULL; j = path_join(*d, path); if (!j) return -ENOMEM; r = read_full_file_full( AT_FDCWD, j, /* path is absolute, hence pass AT_FDCWD as nop dir fd here */ UINT64_MAX, maxsz, flags, NULL, &data, &size); if (r != -ENOENT) break; } } else if (source) r = read_full_file_full( read_dfd, source, UINT64_MAX, maxsz, flags, bindname, &data, &size); else r = -ENOENT; if (r == -ENOENT && (missing_ok || hashmap_contains(context->set_credentials, id))) { /* Make a missing inherited credential non-fatal, let's just continue. After all apps * will get clear errors if we don't pass such a missing credential on as they * themselves will get ENOENT when trying to read them, which should not be much * worse than when we handle the error here and make it fatal. * * Also, if the source file doesn't exist, but a fallback is set via SetCredentials= * we are fine, too. */ log_debug_errno(r, "Couldn't read inherited credential '%s', skipping: %m", path); return 0; } if (r < 0) return log_debug_errno(r, "Failed to read credential '%s': %m", path); if (encrypted) { _cleanup_free_ void *plaintext = NULL; size_t plaintext_size = 0; r = decrypt_credential_and_warn(id, now(CLOCK_REALTIME), NULL, NULL, data, size, &plaintext, &plaintext_size); if (r < 0) return r; free_and_replace(data, plaintext); size = plaintext_size; } add = strlen(id) + size; if (add > *left) return -E2BIG; r = write_credential(write_dfd, id, data, size, uid, ownership_ok); if (r < 0) return log_debug_errno(r, "Failed to write credential '%s': %m", id); *left -= add; return 0; } struct load_cred_args { const ExecContext *context; const ExecParameters *params; bool encrypted; const char *unit; int dfd; uid_t uid; bool ownership_ok; uint64_t *left; }; static int load_cred_recurse_dir_cb( RecurseDirEvent event, const char *path, int dir_fd, int inode_fd, const struct dirent *de, const struct statx *sx, void *userdata) { struct load_cred_args *args = ASSERT_PTR(userdata); _cleanup_free_ char *sub_id = NULL; int r; if (event != RECURSE_DIR_ENTRY) return RECURSE_DIR_CONTINUE; if (!IN_SET(de->d_type, DT_REG, DT_SOCK)) return RECURSE_DIR_CONTINUE; sub_id = strreplace(path, "/", "_"); if (!sub_id) return -ENOMEM; if (!credential_name_valid(sub_id)) return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Credential would get ID %s, which is not valid, refusing", sub_id); if (faccessat(args->dfd, sub_id, F_OK, AT_SYMLINK_NOFOLLOW) >= 0) { log_debug("Skipping credential with duplicated ID %s at %s", sub_id, path); return RECURSE_DIR_CONTINUE; } if (errno != ENOENT) return log_debug_errno(errno, "Failed to test if credential %s exists: %m", sub_id); r = load_credential( args->context, args->params, sub_id, de->d_name, args->encrypted, args->unit, dir_fd, args->dfd, args->uid, args->ownership_ok, args->left); if (r < 0) return r; return RECURSE_DIR_CONTINUE; } static int acquire_credentials( const ExecContext *context, const ExecParameters *params, const char *unit, const char *p, uid_t uid, bool ownership_ok) { uint64_t left = CREDENTIALS_TOTAL_SIZE_MAX; _cleanup_close_ int dfd = -EBADF; ExecLoadCredential *lc; ExecSetCredential *sc; int r; assert(context); assert(p); dfd = open(p, O_DIRECTORY|O_CLOEXEC); if (dfd < 0) return -errno; /* First, load credentials off disk (or acquire via AF_UNIX socket) */ HASHMAP_FOREACH(lc, context->load_credentials) { _cleanup_close_ int sub_fd = -EBADF; /* If this is an absolute path, then try to open it as a directory. If that works, then we'll * recurse into it. If it is an absolute path but it isn't a directory, then we'll open it as * a regular file. Finally, if it's a relative path we will use it as a credential name to * propagate a credential passed to us from further up. */ if (path_is_absolute(lc->path)) { sub_fd = open(lc->path, O_DIRECTORY|O_CLOEXEC|O_RDONLY); if (sub_fd < 0 && !IN_SET(errno, ENOTDIR, /* Not a directory */ ENOENT)) /* Doesn't exist? */ return log_debug_errno(errno, "Failed to open '%s': %m", lc->path); } if (sub_fd < 0) /* Regular file (incl. a credential passed in from higher up) */ r = load_credential( context, params, lc->id, lc->path, lc->encrypted, unit, AT_FDCWD, dfd, uid, ownership_ok, &left); else /* Directory */ r = recurse_dir( sub_fd, /* path= */ lc->id, /* recurse_dir() will suffix the subdir paths from here to the top-level id */ /* statx_mask= */ 0, /* n_depth_max= */ UINT_MAX, RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_ENSURE_TYPE, load_cred_recurse_dir_cb, &(struct load_cred_args) { .context = context, .params = params, .encrypted = lc->encrypted, .unit = unit, .dfd = dfd, .uid = uid, .ownership_ok = ownership_ok, .left = &left, }); if (r < 0) return r; } /* Second, we add in literally specified credentials. If the credentials already exist, we'll not add * them, so that they can act as a "default" if the same credential is specified multiple times. */ HASHMAP_FOREACH(sc, context->set_credentials) { _cleanup_(erase_and_freep) void *plaintext = NULL; const char *data; size_t size, add; /* Note that we check ahead of time here instead of relying on O_EXCL|O_CREAT later to return * EEXIST if the credential already exists. That's because the TPM2-based decryption is kinda * slow and involved, hence it's nice to be able to skip that if the credential already * exists anyway. */ if (faccessat(dfd, sc->id, F_OK, AT_SYMLINK_NOFOLLOW) >= 0) continue; if (errno != ENOENT) return log_debug_errno(errno, "Failed to test if credential %s exists: %m", sc->id); if (sc->encrypted) { r = decrypt_credential_and_warn(sc->id, now(CLOCK_REALTIME), NULL, NULL, sc->data, sc->size, &plaintext, &size); if (r < 0) return r; data = plaintext; } else { data = sc->data; size = sc->size; } add = strlen(sc->id) + size; if (add > left) return -E2BIG; r = write_credential(dfd, sc->id, data, size, uid, ownership_ok); if (r < 0) return r; left -= add; } if (fchmod(dfd, 0500) < 0) /* Now take away the "w" bit */ return -errno; /* After we created all keys with the right perms, also make sure the credential store as a whole is * accessible */ if (uid_is_valid(uid) && uid != getuid()) { r = fd_add_uid_acl_permission(dfd, uid, ACL_READ | ACL_EXECUTE); if (r < 0) { if (!ERRNO_IS_NOT_SUPPORTED(r) && !ERRNO_IS_PRIVILEGE(r)) return r; if (!ownership_ok) return r; if (fchown(dfd, uid, GID_INVALID) < 0) return -errno; } } return 0; } static int setup_credentials_internal( const ExecContext *context, const ExecParameters *params, const char *unit, const char *final, /* This is where the credential store shall eventually end up at */ const char *workspace, /* This is where we can prepare it before moving it to the final place */ bool reuse_workspace, /* Whether to reuse any existing workspace mount if it already is a mount */ bool must_mount, /* Whether to require that we mount something, it's not OK to use the plain directory fall back */ uid_t uid) { int r, workspace_mounted; /* negative if we don't know yet whether we have/can mount something; true * if we mounted something; false if we definitely can't mount anything */ bool final_mounted; const char *where; assert(context); assert(final); assert(workspace); if (reuse_workspace) { r = path_is_mount_point(workspace, NULL, 0); if (r < 0) return r; if (r > 0) workspace_mounted = true; /* If this is already a mount, and we are supposed to reuse it, let's keep this in mind */ else workspace_mounted = -1; /* We need to figure out if we can mount something to the workspace */ } else workspace_mounted = -1; /* ditto */ r = path_is_mount_point(final, NULL, 0); if (r < 0) return r; if (r > 0) { /* If the final place already has something mounted, we use that. If the workspace also has * something mounted we assume it's actually the same mount (but with MS_RDONLY * different). */ final_mounted = true; if (workspace_mounted < 0) { /* If the final place is mounted, but the workspace isn't, then let's bind mount * the final version to the workspace, and make it writable, so that we can make * changes */ r = mount_nofollow_verbose(LOG_DEBUG, final, workspace, NULL, MS_BIND|MS_REC, NULL); if (r < 0) return r; r = mount_nofollow_verbose(LOG_DEBUG, NULL, workspace, NULL, MS_BIND|MS_REMOUNT|MS_NODEV|MS_NOEXEC|MS_NOSUID, NULL); if (r < 0) return r; workspace_mounted = true; } } else final_mounted = false; if (workspace_mounted < 0) { /* Nothing is mounted on the workspace yet, let's try to mount something now */ for (int try = 0;; try++) { if (try == 0) { /* Try "ramfs" first, since it's not swap backed */ r = mount_nofollow_verbose(LOG_DEBUG, "ramfs", workspace, "ramfs", MS_NODEV|MS_NOEXEC|MS_NOSUID, "mode=0700"); if (r >= 0) { workspace_mounted = true; break; } } else if (try == 1) { _cleanup_free_ char *opts = NULL; if (asprintf(&opts, "mode=0700,nr_inodes=1024,size=%zu", (size_t) CREDENTIALS_TOTAL_SIZE_MAX) < 0) return -ENOMEM; /* Fall back to "tmpfs" otherwise */ r = mount_nofollow_verbose(LOG_DEBUG, "tmpfs", workspace, "tmpfs", MS_NODEV|MS_NOEXEC|MS_NOSUID, opts); if (r >= 0) { workspace_mounted = true; break; } } else { /* If that didn't work, try to make a bind mount from the final to the workspace, so that we can make it writable there. */ r = mount_nofollow_verbose(LOG_DEBUG, final, workspace, NULL, MS_BIND|MS_REC, NULL); if (r < 0) { if (!ERRNO_IS_PRIVILEGE(r)) /* Propagate anything that isn't a permission problem */ return r; if (must_mount) /* If we it's not OK to use the plain directory * fallback, propagate all errors too */ return r; /* If we lack privileges to bind mount stuff, then let's gracefully * proceed for compat with container envs, and just use the final dir * as is. */ workspace_mounted = false; break; } /* Make the new bind mount writable (i.e. drop MS_RDONLY) */ r = mount_nofollow_verbose(LOG_DEBUG, NULL, workspace, NULL, MS_BIND|MS_REMOUNT|MS_NODEV|MS_NOEXEC|MS_NOSUID, NULL); if (r < 0) return r; workspace_mounted = true; break; } } } assert(!must_mount || workspace_mounted > 0); where = workspace_mounted ? workspace : final; (void) label_fix_full(AT_FDCWD, where, final, 0); r = acquire_credentials(context, params, unit, where, uid, workspace_mounted); if (r < 0) return r; if (workspace_mounted) { bool install; /* Determine if we should actually install the prepared mount in the final location by bind * mounting it there. We do so only if the mount is not established there already, and if the * mount is actually non-empty (i.e. carries at least one credential). Not that in the best * case we are doing all this in a mount namespace, thus noone else will see that we * allocated a file system we are getting rid of again here. */ if (final_mounted) install = false; /* already installed */ else { r = dir_is_empty(where, /* ignore_hidden_or_backup= */ false); if (r < 0) return r; install = r == 0; /* install only if non-empty */ } if (install) { /* Make workspace read-only now, so that any bind mount we make from it defaults to read-only too */ r = mount_nofollow_verbose(LOG_DEBUG, NULL, workspace, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY|MS_NODEV|MS_NOEXEC|MS_NOSUID, NULL); if (r < 0) return r; /* And mount it to the final place, read-only */ r = mount_nofollow_verbose(LOG_DEBUG, workspace, final, NULL, MS_MOVE, NULL); } else /* Otherwise get rid of it */ r = umount_verbose(LOG_DEBUG, workspace, MNT_DETACH|UMOUNT_NOFOLLOW); if (r < 0) return r; } else { _cleanup_free_ char *parent = NULL; /* If we do not have our own mount put used the plain directory fallback, then we need to * open access to the top-level credential directory and the per-service directory now */ r = path_extract_directory(final, &parent); if (r < 0) return r; if (chmod(parent, 0755) < 0) return -errno; } return 0; } static int setup_credentials( const ExecContext *context, const ExecParameters *params, const char *unit, uid_t uid) { _cleanup_free_ char *p = NULL, *q = NULL; int r; assert(context); assert(params); if (!exec_context_has_credentials(context)) return 0; if (!params->prefix[EXEC_DIRECTORY_RUNTIME]) return -EINVAL; /* This where we'll place stuff when we are done; this main credentials directory is world-readable, * and the subdir we mount over with a read-only file system readable by the service's user */ q = path_join(params->prefix[EXEC_DIRECTORY_RUNTIME], "credentials"); if (!q) return -ENOMEM; r = mkdir_label(q, 0755); /* top-level dir: world readable/searchable */ if (r < 0 && r != -EEXIST) return r; p = path_join(q, unit); if (!p) return -ENOMEM; r = mkdir_label(p, 0700); /* per-unit dir: private to user */ if (r < 0 && r != -EEXIST) return r; r = safe_fork("(sd-mkdcreds)", FORK_DEATHSIG|FORK_WAIT|FORK_NEW_MOUNTNS, NULL); if (r < 0) { _cleanup_free_ char *t = NULL, *u = NULL; /* If this is not a privilege or support issue then propagate the error */ if (!ERRNO_IS_NOT_SUPPORTED(r) && !ERRNO_IS_PRIVILEGE(r)) return r; /* Temporary workspace, that remains inaccessible all the time. We prepare stuff there before moving * it into place, so that users can't access half-initialized credential stores. */ t = path_join(params->prefix[EXEC_DIRECTORY_RUNTIME], "systemd/temporary-credentials"); if (!t) return -ENOMEM; /* We can't set up a mount namespace. In that case operate on a fixed, inaccessible per-unit * directory outside of /run/credentials/ first, and then move it over to /run/credentials/ * after it is fully set up */ u = path_join(t, unit); if (!u) return -ENOMEM; FOREACH_STRING(i, t, u) { r = mkdir_label(i, 0700); if (r < 0 && r != -EEXIST) return r; } r = setup_credentials_internal( context, params, unit, p, /* final mount point */ u, /* temporary workspace to overmount */ true, /* reuse the workspace if it is already a mount */ false, /* it's OK to fall back to a plain directory if we can't mount anything */ uid); (void) rmdir(u); /* remove the workspace again if we can. */ if (r < 0) return r; } else if (r == 0) { /* We managed to set up a mount namespace, and are now in a child. That's great. In this case * we can use the same directory for all cases, after turning off propagation. Question * though is: where do we turn off propagation exactly, and where do we place the workspace * directory? We need some place that is guaranteed to be a mount point in the host, and * which is guaranteed to have a subdir we can mount over. /run/ is not suitable for this, * since we ultimately want to move the resulting file system there, i.e. we need propagation * for /run/ eventually. We could use our own /run/systemd/bind mount on itself, but that * would be visible in the host mount table all the time, which we want to avoid. Hence, what * we do here instead we use /dev/ and /dev/shm/ for our purposes. We know for sure that * /dev/ is a mount point and we now for sure that /dev/shm/ exists. Hence we can turn off * propagation on the former, and then overmount the latter. * * Yes it's nasty playing games with /dev/ and /dev/shm/ like this, since it does not exist * for this purpose, but there are few other candidates that work equally well for us, and * given that the we do this in a privately namespaced short-lived single-threaded process * that no one else sees this should be OK to do. */ r = mount_nofollow_verbose(LOG_DEBUG, NULL, "/dev", NULL, MS_SLAVE|MS_REC, NULL); /* Turn off propagation from our namespace to host */ if (r < 0) goto child_fail; r = setup_credentials_internal( context, params, unit, p, /* final mount point */ "/dev/shm", /* temporary workspace to overmount */ false, /* do not reuse /dev/shm if it is already a mount, under no circumstances */ true, /* insist that something is mounted, do not allow fallback to plain directory */ uid); if (r < 0) goto child_fail; _exit(EXIT_SUCCESS); child_fail: _exit(EXIT_FAILURE); } /* If the credentials dir is empty and not a mount point, then there's no point in having it. Let's * try to remove it. This matters in particular if we created the dir as mount point but then didn't * actually end up mounting anything on it. In that case we'd rather have ENOENT than EACCESS being * seen by users when trying access this inode. */ (void) rmdir(p); return 0; } #if ENABLE_SMACK static int setup_smack( const Manager *manager, const ExecContext *context, int executable_fd) { int r; assert(context); assert(executable_fd >= 0); if (context->smack_process_label) { r = mac_smack_apply_pid(0, context->smack_process_label); if (r < 0) return r; } else if (manager->default_smack_process_label) { _cleanup_free_ char *exec_label = NULL; r = mac_smack_read_fd(executable_fd, SMACK_ATTR_EXEC, &exec_label); if (r < 0 && !ERRNO_IS_XATTR_ABSENT(r)) return r; r = mac_smack_apply_pid(0, exec_label ?: manager->default_smack_process_label); if (r < 0) return r; } return 0; } #endif static int compile_bind_mounts( const ExecContext *context, const ExecParameters *params, BindMount **ret_bind_mounts, size_t *ret_n_bind_mounts, char ***ret_empty_directories) { _cleanup_strv_free_ char **empty_directories = NULL; BindMount *bind_mounts = NULL; size_t n, h = 0; int r; assert(context); assert(params); assert(ret_bind_mounts); assert(ret_n_bind_mounts); assert(ret_empty_directories); CLEANUP_ARRAY(bind_mounts, h, bind_mount_free_many); n = context->n_bind_mounts; for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) { if (!params->prefix[t]) continue; for (size_t i = 0; i < context->directories[t].n_items; i++) n += !context->directories[t].items[i].only_create; } if (n <= 0) { *ret_bind_mounts = NULL; *ret_n_bind_mounts = 0; *ret_empty_directories = NULL; return 0; } bind_mounts = new(BindMount, n); if (!bind_mounts) return -ENOMEM; for (size_t i = 0; i < context->n_bind_mounts; i++) { BindMount *item = context->bind_mounts + i; _cleanup_free_ char *s = NULL, *d = NULL; s = strdup(item->source); if (!s) return -ENOMEM; d = strdup(item->destination); if (!d) return -ENOMEM; bind_mounts[h++] = (BindMount) { .source = TAKE_PTR(s), .destination = TAKE_PTR(d), .read_only = item->read_only, .recursive = item->recursive, .ignore_enoent = item->ignore_enoent, }; } for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) { if (!params->prefix[t]) continue; if (context->directories[t].n_items == 0) continue; if (exec_directory_is_private(context, t) && !exec_context_with_rootfs(context)) { char *private_root; /* So this is for a dynamic user, and we need to make sure the process can access its own * directory. For that we overmount the usually inaccessible "private" subdirectory with a * tmpfs that makes it accessible and is empty except for the submounts we do this for. */ private_root = path_join(params->prefix[t], "private"); if (!private_root) return -ENOMEM; r = strv_consume(&empty_directories, private_root); if (r < 0) return r; } for (size_t i = 0; i < context->directories[t].n_items; i++) { _cleanup_free_ char *s = NULL, *d = NULL; /* When one of the parent directories is in the list, we cannot create the symlink * for the child directory. See also the comments in setup_exec_directory(). */ if (context->directories[t].items[i].only_create) continue; if (exec_directory_is_private(context, t)) s = path_join(params->prefix[t], "private", context->directories[t].items[i].path); else s = path_join(params->prefix[t], context->directories[t].items[i].path); if (!s) return -ENOMEM; if (exec_directory_is_private(context, t) && exec_context_with_rootfs(context)) /* When RootDirectory= or RootImage= are set, then the symbolic link to the private * directory is not created on the root directory. So, let's bind-mount the directory * on the 'non-private' place. */ d = path_join(params->prefix[t], context->directories[t].items[i].path); else d = strdup(s); if (!d) return -ENOMEM; bind_mounts[h++] = (BindMount) { .source = TAKE_PTR(s), .destination = TAKE_PTR(d), .read_only = false, .nosuid = context->dynamic_user, /* don't allow suid/sgid when DynamicUser= is on */ .recursive = true, .ignore_enoent = false, }; } } assert(h == n); *ret_bind_mounts = TAKE_PTR(bind_mounts); *ret_n_bind_mounts = n; *ret_empty_directories = TAKE_PTR(empty_directories); return (int) n; } /* ret_symlinks will contain a list of pairs src:dest that describes * the symlinks to create later on. For example, the symlinks needed * to safely give private directories to DynamicUser=1 users. */ static int compile_symlinks( const ExecContext *context, const ExecParameters *params, char ***ret_symlinks) { _cleanup_strv_free_ char **symlinks = NULL; int r; assert(context); assert(params); assert(ret_symlinks); for (ExecDirectoryType dt = 0; dt < _EXEC_DIRECTORY_TYPE_MAX; dt++) { for (size_t i = 0; i < context->directories[dt].n_items; i++) { _cleanup_free_ char *private_path = NULL, *path = NULL; STRV_FOREACH(symlink, context->directories[dt].items[i].symlinks) { _cleanup_free_ char *src_abs = NULL, *dst_abs = NULL; src_abs = path_join(params->prefix[dt], context->directories[dt].items[i].path); dst_abs = path_join(params->prefix[dt], *symlink); if (!src_abs || !dst_abs) return -ENOMEM; r = strv_consume_pair(&symlinks, TAKE_PTR(src_abs), TAKE_PTR(dst_abs)); if (r < 0) return r; } if (!exec_directory_is_private(context, dt) || exec_context_with_rootfs(context) || context->directories[dt].items[i].only_create) continue; private_path = path_join(params->prefix[dt], "private", context->directories[dt].items[i].path); if (!private_path) return -ENOMEM; path = path_join(params->prefix[dt], context->directories[dt].items[i].path); if (!path) return -ENOMEM; r = strv_consume_pair(&symlinks, TAKE_PTR(private_path), TAKE_PTR(path)); if (r < 0) return r; } } *ret_symlinks = TAKE_PTR(symlinks); return 0; } static bool insist_on_sandboxing( const ExecContext *context, const char *root_dir, const char *root_image, const BindMount *bind_mounts, size_t n_bind_mounts) { assert(context); assert(n_bind_mounts == 0 || bind_mounts); /* Checks whether we need to insist on fs namespacing. i.e. whether we have settings configured that * would alter the view on the file system beyond making things read-only or invisible, i.e. would * rearrange stuff in a way we cannot ignore gracefully. */ if (context->n_temporary_filesystems > 0) return true; if (root_dir || root_image) return true; if (context->n_mount_images > 0) return true; if (context->dynamic_user) return true; if (context->n_extension_images > 0 || !strv_isempty(context->extension_directories)) return true; /* If there are any bind mounts set that don't map back onto themselves, fs namespacing becomes * essential. */ for (size_t i = 0; i < n_bind_mounts; i++) if (!path_equal(bind_mounts[i].source, bind_mounts[i].destination)) return true; if (context->log_namespace) return true; return false; } static int apply_mount_namespace( const Unit *u, ExecCommandFlags command_flags, const ExecContext *context, const ExecParameters *params, const ExecRuntime *runtime, const char *memory_pressure_path, char **error_path) { _cleanup_strv_free_ char **empty_directories = NULL, **symlinks = NULL, **read_write_paths_cleanup = NULL; const char *tmp_dir = NULL, *var_tmp_dir = NULL; const char *root_dir = NULL, *root_image = NULL; _cleanup_free_ char *creds_path = NULL, *incoming_dir = NULL, *propagate_dir = NULL, *extension_dir = NULL; char **read_write_paths; NamespaceInfo ns_info; bool needs_sandboxing; BindMount *bind_mounts = NULL; size_t n_bind_mounts = 0; int r; assert(context); CLEANUP_ARRAY(bind_mounts, n_bind_mounts, bind_mount_free_many); if (params->flags & EXEC_APPLY_CHROOT) { root_image = context->root_image; if (!root_image) root_dir = context->root_directory; } r = compile_bind_mounts(context, params, &bind_mounts, &n_bind_mounts, &empty_directories); if (r < 0) return r; /* Symlinks for exec dirs are set up after other mounts, before they are made read-only. */ r = compile_symlinks(context, params, &symlinks); if (r < 0) return r; /* We need to make the pressure path writable even if /sys/fs/cgroups is made read-only, as the * service will need to write to it in order to start the notifications. */ if (context->protect_control_groups && memory_pressure_path && !streq(memory_pressure_path, "/dev/null")) { read_write_paths_cleanup = strv_copy(context->read_write_paths); if (!read_write_paths_cleanup) return -ENOMEM; r = strv_extend(&read_write_paths_cleanup, memory_pressure_path); if (r < 0) return r; read_write_paths = read_write_paths_cleanup; } else read_write_paths = context->read_write_paths; needs_sandboxing = (params->flags & EXEC_APPLY_SANDBOXING) && !(command_flags & EXEC_COMMAND_FULLY_PRIVILEGED); if (needs_sandboxing) { /* The runtime struct only contains the parent of the private /tmp, * which is non-accessible to world users. Inside of it there's a /tmp * that is sticky, and that's the one we want to use here. * This does not apply when we are using /run/systemd/empty as fallback. */ if (context->private_tmp && runtime && runtime->shared) { if (streq_ptr(runtime->shared->tmp_dir, RUN_SYSTEMD_EMPTY)) tmp_dir = runtime->shared->tmp_dir; else if (runtime->shared->tmp_dir) tmp_dir = strjoina(runtime->shared->tmp_dir, "/tmp"); if (streq_ptr(runtime->shared->var_tmp_dir, RUN_SYSTEMD_EMPTY)) var_tmp_dir = runtime->shared->var_tmp_dir; else if (runtime->shared->var_tmp_dir) var_tmp_dir = strjoina(runtime->shared->var_tmp_dir, "/tmp"); } ns_info = (NamespaceInfo) { .ignore_protect_paths = false, .private_dev = context->private_devices, .protect_control_groups = context->protect_control_groups, .protect_kernel_tunables = context->protect_kernel_tunables, .protect_kernel_modules = context->protect_kernel_modules, .protect_kernel_logs = context->protect_kernel_logs, .protect_hostname = context->protect_hostname, .mount_apivfs = exec_context_get_effective_mount_apivfs(context), .protect_home = context->protect_home, .protect_system = context->protect_system, .protect_proc = context->protect_proc, .proc_subset = context->proc_subset, .private_network = exec_needs_network_namespace(context), .private_ipc = exec_needs_ipc_namespace(context), /* If NNP is on, we can turn on MS_NOSUID, since it won't have any effect anymore. */ .mount_nosuid = context->no_new_privileges && !mac_selinux_use(), }; } else if (!context->dynamic_user && root_dir) /* * If DynamicUser=no and RootDirectory= is set then lets pass a relaxed * sandbox info, otherwise enforce it, don't ignore protected paths and * fail if we are enable to apply the sandbox inside the mount namespace. */ ns_info = (NamespaceInfo) { .ignore_protect_paths = true, }; else ns_info = (NamespaceInfo) {}; if (context->mount_propagation_flag == MS_SHARED) log_unit_debug(u, "shared mount propagation hidden by other fs namespacing unit settings: ignoring"); if (exec_context_has_credentials(context) && params->prefix[EXEC_DIRECTORY_RUNTIME] && FLAGS_SET(params->flags, EXEC_WRITE_CREDENTIALS)) { creds_path = path_join(params->prefix[EXEC_DIRECTORY_RUNTIME], "credentials", u->id); if (!creds_path) return -ENOMEM; } if (MANAGER_IS_SYSTEM(u->manager)) { propagate_dir = path_join("/run/systemd/propagate/", u->id); if (!propagate_dir) return -ENOMEM; incoming_dir = strdup("/run/systemd/incoming"); if (!incoming_dir) return -ENOMEM; extension_dir = strdup("/run/systemd/unit-extensions"); if (!extension_dir) return -ENOMEM; } else if (asprintf(&extension_dir, "/run/user/" UID_FMT "/systemd/unit-extensions", geteuid()) < 0) return -ENOMEM; r = setup_namespace( root_dir, root_image, context->root_image_options, context->root_image_policy ?: &image_policy_service, &ns_info, read_write_paths, needs_sandboxing ? context->read_only_paths : NULL, needs_sandboxing ? context->inaccessible_paths : NULL, needs_sandboxing ? context->exec_paths : NULL, needs_sandboxing ? context->no_exec_paths : NULL, empty_directories, symlinks, bind_mounts, n_bind_mounts, context->temporary_filesystems, context->n_temporary_filesystems, context->mount_images, context->n_mount_images, context->mount_image_policy ?: &image_policy_service, tmp_dir, var_tmp_dir, creds_path, context->log_namespace, context->mount_propagation_flag, context->root_hash, context->root_hash_size, context->root_hash_path, context->root_hash_sig, context->root_hash_sig_size, context->root_hash_sig_path, context->root_verity, context->extension_images, context->n_extension_images, context->extension_image_policy ?: &image_policy_sysext, context->extension_directories, propagate_dir, incoming_dir, extension_dir, root_dir || root_image ? params->notify_socket : NULL, error_path); /* If we couldn't set up the namespace this is probably due to a missing capability. setup_namespace() reports * that with a special, recognizable error ENOANO. In this case, silently proceed, but only if exclusively * sandboxing options were used, i.e. nothing such as RootDirectory= or BindMount= that would result in a * completely different execution environment. */ if (r == -ENOANO) { if (insist_on_sandboxing( context, root_dir, root_image, bind_mounts, n_bind_mounts)) return log_unit_debug_errno(u, SYNTHETIC_ERRNO(EOPNOTSUPP), "Failed to set up namespace, and refusing to continue since " "the selected namespacing options alter mount environment non-trivially.\n" "Bind mounts: %zu, temporary filesystems: %zu, root directory: %s, root image: %s, dynamic user: %s", n_bind_mounts, context->n_temporary_filesystems, yes_no(root_dir), yes_no(root_image), yes_no(context->dynamic_user)); log_unit_debug(u, "Failed to set up namespace, assuming containerized execution and ignoring."); return 0; } return r; } static int apply_working_directory( const ExecContext *context, const ExecParameters *params, const char *home, int *exit_status) { const char *d, *wd; assert(context); assert(exit_status); if (context->working_directory_home) { if (!home) { *exit_status = EXIT_CHDIR; return -ENXIO; } wd = home; } else wd = empty_to_root(context->working_directory); if (params->flags & EXEC_APPLY_CHROOT) d = wd; else d = prefix_roota(context->root_directory, wd); if (chdir(d) < 0 && !context->working_directory_missing_ok) { *exit_status = EXIT_CHDIR; return -errno; } return 0; } static int apply_root_directory( const ExecContext *context, const ExecParameters *params, const bool needs_mount_ns, int *exit_status) { assert(context); assert(exit_status); if (params->flags & EXEC_APPLY_CHROOT) if (!needs_mount_ns && context->root_directory) if (chroot(context->root_directory) < 0) { *exit_status = EXIT_CHROOT; return -errno; } return 0; } static int setup_keyring( const Unit *u, const ExecContext *context, const ExecParameters *p, uid_t uid, gid_t gid) { key_serial_t keyring; int r = 0; uid_t saved_uid; gid_t saved_gid; assert(u); assert(context); assert(p); /* Let's set up a new per-service "session" kernel keyring for each system service. This has the benefit that * each service runs with its own keyring shared among all processes of the service, but with no hook-up beyond * that scope, and in particular no link to the per-UID keyring. If we don't do this the keyring will be * automatically created on-demand and then linked to the per-UID keyring, by the kernel. The kernel's built-in * on-demand behaviour is very appropriate for login users, but probably not so much for system services, where * UIDs are not necessarily specific to a service but reused (at least in the case of UID 0). */ if (context->keyring_mode == EXEC_KEYRING_INHERIT) return 0; /* Acquiring a reference to the user keyring is nasty. We briefly change identity in order to get things set up * properly by the kernel. If we don't do that then we can't create it atomically, and that sucks for parallel * execution. This mimics what pam_keyinit does, too. Setting up session keyring, to be owned by the right user * & group is just as nasty as acquiring a reference to the user keyring. */ saved_uid = getuid(); saved_gid = getgid(); if (gid_is_valid(gid) && gid != saved_gid) { if (setregid(gid, -1) < 0) return log_unit_error_errno(u, errno, "Failed to change GID for user keyring: %m"); } if (uid_is_valid(uid) && uid != saved_uid) { if (setreuid(uid, -1) < 0) { r = log_unit_error_errno(u, errno, "Failed to change UID for user keyring: %m"); goto out; } } keyring = keyctl(KEYCTL_JOIN_SESSION_KEYRING, 0, 0, 0, 0); if (keyring == -1) { if (errno == ENOSYS) log_unit_debug_errno(u, errno, "Kernel keyring not supported, ignoring."); else if (ERRNO_IS_PRIVILEGE(errno)) log_unit_debug_errno(u, errno, "Kernel keyring access prohibited, ignoring."); else if (errno == EDQUOT) log_unit_debug_errno(u, errno, "Out of kernel keyrings to allocate, ignoring."); else r = log_unit_error_errno(u, errno, "Setting up kernel keyring failed: %m"); goto out; } /* When requested link the user keyring into the session keyring. */ if (context->keyring_mode == EXEC_KEYRING_SHARED) { if (keyctl(KEYCTL_LINK, KEY_SPEC_USER_KEYRING, KEY_SPEC_SESSION_KEYRING, 0, 0) < 0) { r = log_unit_error_errno(u, errno, "Failed to link user keyring into session keyring: %m"); goto out; } } /* Restore uid/gid back */ if (uid_is_valid(uid) && uid != saved_uid) { if (setreuid(saved_uid, -1) < 0) { r = log_unit_error_errno(u, errno, "Failed to change UID back for user keyring: %m"); goto out; } } if (gid_is_valid(gid) && gid != saved_gid) { if (setregid(saved_gid, -1) < 0) return log_unit_error_errno(u, errno, "Failed to change GID back for user keyring: %m"); } /* Populate they keyring with the invocation ID by default, as original saved_uid. */ if (!sd_id128_is_null(u->invocation_id)) { key_serial_t key; key = add_key("user", "invocation_id", &u->invocation_id, sizeof(u->invocation_id), KEY_SPEC_SESSION_KEYRING); if (key == -1) log_unit_debug_errno(u, errno, "Failed to add invocation ID to keyring, ignoring: %m"); else { if (keyctl(KEYCTL_SETPERM, key, KEY_POS_VIEW|KEY_POS_READ|KEY_POS_SEARCH| KEY_USR_VIEW|KEY_USR_READ|KEY_USR_SEARCH, 0, 0) < 0) r = log_unit_error_errno(u, errno, "Failed to restrict invocation ID permission: %m"); } } out: /* Revert back uid & gid for the last time, and exit */ /* no extra logging, as only the first already reported error matters */ if (getuid() != saved_uid) (void) setreuid(saved_uid, -1); if (getgid() != saved_gid) (void) setregid(saved_gid, -1); return r; } static void append_socket_pair(int *array, size_t *n, const int pair[static 2]) { assert(array); assert(n); assert(pair); if (pair[0] >= 0) array[(*n)++] = pair[0]; if (pair[1] >= 0) array[(*n)++] = pair[1]; } static int close_remaining_fds( const ExecParameters *params, const ExecRuntime *runtime, int user_lookup_fd, int socket_fd, const int *fds, size_t n_fds) { size_t n_dont_close = 0; int dont_close[n_fds + 12]; assert(params); if (params->stdin_fd >= 0) dont_close[n_dont_close++] = params->stdin_fd; if (params->stdout_fd >= 0) dont_close[n_dont_close++] = params->stdout_fd; if (params->stderr_fd >= 0) dont_close[n_dont_close++] = params->stderr_fd; if (socket_fd >= 0) dont_close[n_dont_close++] = socket_fd; if (n_fds > 0) { memcpy(dont_close + n_dont_close, fds, sizeof(int) * n_fds); n_dont_close += n_fds; } if (runtime && runtime->shared) { append_socket_pair(dont_close, &n_dont_close, runtime->shared->netns_storage_socket); append_socket_pair(dont_close, &n_dont_close, runtime->shared->ipcns_storage_socket); } if (runtime && runtime->dynamic_creds) { if (runtime->dynamic_creds->user) append_socket_pair(dont_close, &n_dont_close, runtime->dynamic_creds->user->storage_socket); if (runtime->dynamic_creds->group) append_socket_pair(dont_close, &n_dont_close, runtime->dynamic_creds->group->storage_socket); } if (user_lookup_fd >= 0) dont_close[n_dont_close++] = user_lookup_fd; return close_all_fds(dont_close, n_dont_close); } static int send_user_lookup( Unit *unit, int user_lookup_fd, uid_t uid, gid_t gid) { assert(unit); /* Send the resolved UID/GID to PID 1 after we learnt it. We send a single datagram, containing the UID/GID * data as well as the unit name. Note that we suppress sending this if no user/group to resolve was * specified. */ if (user_lookup_fd < 0) return 0; if (!uid_is_valid(uid) && !gid_is_valid(gid)) return 0; if (writev(user_lookup_fd, (struct iovec[]) { IOVEC_MAKE(&uid, sizeof(uid)), IOVEC_MAKE(&gid, sizeof(gid)), IOVEC_MAKE_STRING(unit->id) }, 3) < 0) return -errno; return 0; } static int acquire_home(const ExecContext *c, uid_t uid, const char** home, char **buf) { int r; assert(c); assert(home); assert(buf); /* If WorkingDirectory=~ is set, try to acquire a usable home directory. */ if (*home) return 0; if (!c->working_directory_home) return 0; r = get_home_dir(buf); if (r < 0) return r; *home = *buf; return 1; } static int compile_suggested_paths(const ExecContext *c, const ExecParameters *p, char ***ret) { _cleanup_strv_free_ char ** list = NULL; int r; assert(c); assert(p); assert(ret); assert(c->dynamic_user); /* Compile a list of paths that it might make sense to read the owning UID from to use as initial candidate for * dynamic UID allocation, in order to save us from doing costly recursive chown()s of the special * directories. */ for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) { if (t == EXEC_DIRECTORY_CONFIGURATION) continue; if (!p->prefix[t]) continue; for (size_t i = 0; i < c->directories[t].n_items; i++) { char *e; if (exec_directory_is_private(c, t)) e = path_join(p->prefix[t], "private", c->directories[t].items[i].path); else e = path_join(p->prefix[t], c->directories[t].items[i].path); if (!e) return -ENOMEM; r = strv_consume(&list, e); if (r < 0) return r; } } *ret = TAKE_PTR(list); return 0; } static int exec_parameters_get_cgroup_path( const ExecParameters *params, const CGroupContext *c, char **ret) { const char *subgroup = NULL; char *p; assert(params); assert(ret); if (!params->cgroup_path) return -EINVAL; /* If we are called for a unit where cgroup delegation is on, and the payload created its own populated * subcgroup (which we expect it to do, after all it asked for delegation), then we cannot place the control * processes started after the main unit's process in the unit's main cgroup because it is now an inner one, * and inner cgroups may not contain processes. Hence, if delegation is on, and this is a control process, * let's use ".control" as subcgroup instead. Note that we do so only for ExecStartPost=, ExecReload=, * ExecStop=, ExecStopPost=, i.e. for the commands where the main process is already forked. For ExecStartPre= * this is not necessary, the cgroup is still empty. We distinguish these cases with the EXEC_CONTROL_CGROUP * flag, which is only passed for the former statements, not for the latter. */ if (FLAGS_SET(params->flags, EXEC_CGROUP_DELEGATE) && (FLAGS_SET(params->flags, EXEC_CONTROL_CGROUP) || c->delegate_subgroup)) { if (FLAGS_SET(params->flags, EXEC_IS_CONTROL)) subgroup = ".control"; else subgroup = c->delegate_subgroup; } if (subgroup) p = path_join(params->cgroup_path, subgroup); else p = strdup(params->cgroup_path); if (!p) return -ENOMEM; *ret = p; return !!subgroup; } static int exec_context_cpu_affinity_from_numa(const ExecContext *c, CPUSet *ret) { _cleanup_(cpu_set_reset) CPUSet s = {}; int r; assert(c); assert(ret); if (!c->numa_policy.nodes.set) { log_debug("Can't derive CPU affinity mask from NUMA mask because NUMA mask is not set, ignoring"); return 0; } r = numa_to_cpu_set(&c->numa_policy, &s); if (r < 0) return r; cpu_set_reset(ret); return cpu_set_add_all(ret, &s); } bool exec_context_get_cpu_affinity_from_numa(const ExecContext *c) { assert(c); return c->cpu_affinity_from_numa; } static int add_shifted_fd(int *fds, size_t fds_size, size_t *n_fds, int fd, int *ret_fd) { int r; assert(fds); assert(n_fds); assert(*n_fds < fds_size); assert(ret_fd); if (fd < 0) { *ret_fd = -EBADF; return 0; } if (fd < 3 + (int) *n_fds) { /* Let's move the fd up, so that it's outside of the fd range we will use to store * the fds we pass to the process (or which are closed only during execve). */ r = fcntl(fd, F_DUPFD_CLOEXEC, 3 + (int) *n_fds); if (r < 0) return -errno; close_and_replace(fd, r); } *ret_fd = fds[*n_fds] = fd; (*n_fds) ++; return 1; } static int connect_unix_harder(Unit *u, const OpenFile *of, int ofd) { union sockaddr_union addr = { .un.sun_family = AF_UNIX, }; socklen_t sa_len; static const int socket_types[] = { SOCK_DGRAM, SOCK_STREAM, SOCK_SEQPACKET }; int r; assert(u); assert(of); assert(ofd >= 0); r = sockaddr_un_set_path(&addr.un, FORMAT_PROC_FD_PATH(ofd)); if (r < 0) return log_unit_error_errno(u, r, "Failed to set sockaddr for %s: %m", of->path); sa_len = r; for (size_t i = 0; i < ELEMENTSOF(socket_types); i++) { _cleanup_close_ int fd = -EBADF; fd = socket(AF_UNIX, socket_types[i] | SOCK_CLOEXEC, 0); if (fd < 0) return log_unit_error_errno(u, errno, "Failed to create socket for %s: %m", of->path); r = RET_NERRNO(connect(fd, &addr.sa, sa_len)); if (r == -EPROTOTYPE) continue; if (r < 0) return log_unit_error_errno(u, r, "Failed to connect socket for %s: %m", of->path); return TAKE_FD(fd); } return log_unit_error_errno(u, SYNTHETIC_ERRNO(EPROTOTYPE), "Failed to connect socket for \"%s\".", of->path); } static int get_open_file_fd(Unit *u, const OpenFile *of) { struct stat st; _cleanup_close_ int fd = -EBADF, ofd = -EBADF; assert(u); assert(of); ofd = open(of->path, O_PATH | O_CLOEXEC); if (ofd < 0) return log_unit_error_errno(u, errno, "Could not open \"%s\": %m", of->path); if (fstat(ofd, &st) < 0) return log_unit_error_errno(u, errno, "Failed to stat %s: %m", of->path); if (S_ISSOCK(st.st_mode)) { fd = connect_unix_harder(u, of, ofd); if (fd < 0) return fd; if (FLAGS_SET(of->flags, OPENFILE_READ_ONLY) && shutdown(fd, SHUT_WR) < 0) return log_unit_error_errno(u, errno, "Failed to shutdown send for socket %s: %m", of->path); log_unit_debug(u, "socket %s opened (fd=%d)", of->path, fd); } else { int flags = FLAGS_SET(of->flags, OPENFILE_READ_ONLY) ? O_RDONLY : O_RDWR; if (FLAGS_SET(of->flags, OPENFILE_APPEND)) flags |= O_APPEND; else if (FLAGS_SET(of->flags, OPENFILE_TRUNCATE)) flags |= O_TRUNC; fd = fd_reopen(ofd, flags | O_CLOEXEC); if (fd < 0) return log_unit_error_errno(u, fd, "Failed to open file %s: %m", of->path); log_unit_debug(u, "file %s opened (fd=%d)", of->path, fd); } return TAKE_FD(fd); } static int collect_open_file_fds( Unit *u, OpenFile* open_files, int **fds, char ***fdnames, size_t *n_fds) { int r; assert(u); assert(fds); assert(fdnames); assert(n_fds); LIST_FOREACH(open_files, of, open_files) { _cleanup_close_ int fd = -EBADF; fd = get_open_file_fd(u, of); if (fd < 0) { if (FLAGS_SET(of->flags, OPENFILE_GRACEFUL)) { log_unit_debug_errno(u, fd, "Failed to get OpenFile= file descriptor for %s, ignoring: %m", of->path); continue; } return fd; } if (!GREEDY_REALLOC(*fds, *n_fds + 1)) return -ENOMEM; r = strv_extend(fdnames, of->fdname); if (r < 0) return r; (*fds)[*n_fds] = TAKE_FD(fd); (*n_fds)++; } return 0; } static void log_command_line(Unit *unit, const char *msg, const char *executable, char **argv) { assert(unit); assert(msg); assert(executable); if (!DEBUG_LOGGING) return; _cleanup_free_ char *cmdline = quote_command_line(argv, SHELL_ESCAPE_EMPTY); log_unit_struct(unit, LOG_DEBUG, "EXECUTABLE=%s", executable, LOG_UNIT_MESSAGE(unit, "%s: %s", msg, strnull(cmdline)), LOG_UNIT_INVOCATION_ID(unit)); } static bool exec_context_need_unprivileged_private_users(const ExecContext *context, const Manager *manager) { assert(context); assert(manager); /* These options require PrivateUsers= when used in user units, as we need to be in a user namespace * to have permission to enable them when not running as root. If we have effective CAP_SYS_ADMIN * (system manager) then we have privileges and don't need this. */ if (MANAGER_IS_SYSTEM(manager)) return false; return context->private_users || context->private_tmp || context->private_devices || context->private_network || context->network_namespace_path || context->private_ipc || context->ipc_namespace_path || context->private_mounts || context->mount_apivfs || context->n_bind_mounts > 0 || context->n_temporary_filesystems > 0 || context->root_directory || !strv_isempty(context->extension_directories) || context->protect_system != PROTECT_SYSTEM_NO || context->protect_home != PROTECT_HOME_NO || context->protect_kernel_tunables || context->protect_kernel_modules || context->protect_kernel_logs || context->protect_control_groups || context->protect_clock || context->protect_hostname || !strv_isempty(context->read_write_paths) || !strv_isempty(context->read_only_paths) || !strv_isempty(context->inaccessible_paths) || !strv_isempty(context->exec_paths) || !strv_isempty(context->no_exec_paths); } static int exec_child( Unit *unit, const ExecCommand *command, const ExecContext *context, const ExecParameters *params, ExecRuntime *runtime, const CGroupContext *cgroup_context, int socket_fd, const int named_iofds[static 3], int *params_fds, size_t n_socket_fds, size_t n_storage_fds, char **files_env, int user_lookup_fd, int *exit_status) { _cleanup_strv_free_ char **our_env = NULL, **pass_env = NULL, **joined_exec_search_path = NULL, **accum_env = NULL, **replaced_argv = NULL; int r, ngids = 0, exec_fd; _cleanup_free_ gid_t *supplementary_gids = NULL; const char *username = NULL, *groupname = NULL; _cleanup_free_ char *home_buffer = NULL, *memory_pressure_path = NULL; const char *home = NULL, *shell = NULL; char **final_argv = NULL; dev_t journal_stream_dev = 0; ino_t journal_stream_ino = 0; bool userns_set_up = false; bool needs_sandboxing, /* Do we need to set up full sandboxing? (i.e. all namespacing, all MAC stuff, caps, yadda yadda */ needs_setuid, /* Do we need to do the actual setresuid()/setresgid() calls? */ needs_mount_namespace, /* Do we need to set up a mount namespace for this kernel? */ needs_ambient_hack; /* Do we need to apply the ambient capabilities hack? */ #if HAVE_SELINUX _cleanup_free_ char *mac_selinux_context_net = NULL; bool use_selinux = false; #endif #if ENABLE_SMACK bool use_smack = false; #endif #if HAVE_APPARMOR bool use_apparmor = false; #endif uid_t saved_uid = getuid(); gid_t saved_gid = getgid(); uid_t uid = UID_INVALID; gid_t gid = GID_INVALID; size_t n_fds = n_socket_fds + n_storage_fds, /* fds to pass to the child */ n_keep_fds; /* total number of fds not to close */ int secure_bits; _cleanup_free_ gid_t *gids_after_pam = NULL; int ngids_after_pam = 0; _cleanup_free_ int *fds = NULL; _cleanup_strv_free_ char **fdnames = NULL; assert(unit); assert(command); assert(context); assert(params); assert(exit_status); /* Explicitly test for CVE-2021-4034 inspired invocations */ assert(command->path); assert(!strv_isempty(command->argv)); rename_process_from_path(command->path); /* We reset exactly these signals, since they are the only ones we set to SIG_IGN in the main * daemon. All others we leave untouched because we set them to SIG_DFL or a valid handler initially, * both of which will be demoted to SIG_DFL. */ (void) default_signals(SIGNALS_CRASH_HANDLER, SIGNALS_IGNORE); if (context->ignore_sigpipe) (void) ignore_signals(SIGPIPE); r = reset_signal_mask(); if (r < 0) { *exit_status = EXIT_SIGNAL_MASK; return log_unit_error_errno(unit, r, "Failed to set process signal mask: %m"); } if (params->idle_pipe) do_idle_pipe_dance(params->idle_pipe); /* Close fds we don't need very early to make sure we don't block init reexecution because it cannot bind its * sockets. Among the fds we close are the logging fds, and we want to keep them closed, so that we don't have * any fds open we don't really want open during the transition. In order to make logging work, we switch the * log subsystem into open_when_needed mode, so that it reopens the logs on every single log call. */ log_forget_fds(); log_set_open_when_needed(true); log_settle_target(); /* In case anything used libc syslog(), close this here, too */ closelog(); fds = newdup(int, params_fds, n_fds); if (!fds) { *exit_status = EXIT_MEMORY; return log_oom(); } fdnames = strv_copy((char**) params->fd_names); if (!fdnames) { *exit_status = EXIT_MEMORY; return log_oom(); } r = collect_open_file_fds(unit, params->open_files, &fds, &fdnames, &n_fds); if (r < 0) { *exit_status = EXIT_FDS; return log_unit_error_errno(unit, r, "Failed to get OpenFile= file descriptors: %m"); } int keep_fds[n_fds + 3]; memcpy_safe(keep_fds, fds, n_fds * sizeof(int)); n_keep_fds = n_fds; r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, params->exec_fd, &exec_fd); if (r < 0) { *exit_status = EXIT_FDS; return log_unit_error_errno(unit, r, "Failed to shift fd and set FD_CLOEXEC: %m"); } #if HAVE_LIBBPF if (unit->manager->restrict_fs) { int bpf_map_fd = lsm_bpf_map_restrict_fs_fd(unit); if (bpf_map_fd < 0) { *exit_status = EXIT_FDS; return log_unit_error_errno(unit, bpf_map_fd, "Failed to get restrict filesystems BPF map fd: %m"); } r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, bpf_map_fd, &bpf_map_fd); if (r < 0) { *exit_status = EXIT_FDS; return log_unit_error_errno(unit, r, "Failed to shift fd and set FD_CLOEXEC: %m"); } } #endif r = close_remaining_fds(params, runtime, user_lookup_fd, socket_fd, keep_fds, n_keep_fds); if (r < 0) { *exit_status = EXIT_FDS; return log_unit_error_errno(unit, r, "Failed to close unwanted file descriptors: %m"); } if (!context->same_pgrp && setsid() < 0) { *exit_status = EXIT_SETSID; return log_unit_error_errno(unit, errno, "Failed to create new process session: %m"); } exec_context_tty_reset(context, params); if (unit_shall_confirm_spawn(unit)) { _cleanup_free_ char *cmdline = NULL; cmdline = quote_command_line(command->argv, SHELL_ESCAPE_EMPTY); if (!cmdline) { *exit_status = EXIT_MEMORY; return log_oom(); } r = ask_for_confirmation(context, params->confirm_spawn, unit, cmdline); if (r != CONFIRM_EXECUTE) { if (r == CONFIRM_PRETEND_SUCCESS) { *exit_status = EXIT_SUCCESS; return 0; } *exit_status = EXIT_CONFIRM; return log_unit_error_errno(unit, SYNTHETIC_ERRNO(ECANCELED), "Execution cancelled by the user"); } } /* We are about to invoke NSS and PAM modules. Let's tell them what we are doing here, maybe they care. This is * used by nss-resolve to disable itself when we are about to start systemd-resolved, to avoid deadlocks. Note * that these env vars do not survive the execve(), which means they really only apply to the PAM and NSS * invocations themselves. Also note that while we'll only invoke NSS modules involved in user management they * might internally call into other NSS modules that are involved in hostname resolution, we never know. */ if (setenv("SYSTEMD_ACTIVATION_UNIT", unit->id, true) != 0 || setenv("SYSTEMD_ACTIVATION_SCOPE", runtime_scope_to_string(unit->manager->runtime_scope), true) != 0) { *exit_status = EXIT_MEMORY; return log_unit_error_errno(unit, errno, "Failed to update environment: %m"); } if (context->dynamic_user && runtime && runtime->dynamic_creds) { _cleanup_strv_free_ char **suggested_paths = NULL; /* On top of that, make sure we bypass our own NSS module nss-systemd comprehensively for any NSS * checks, if DynamicUser=1 is used, as we shouldn't create a feedback loop with ourselves here. */ if (putenv((char*) "SYSTEMD_NSS_DYNAMIC_BYPASS=1") != 0) { *exit_status = EXIT_USER; return log_unit_error_errno(unit, errno, "Failed to update environment: %m"); } r = compile_suggested_paths(context, params, &suggested_paths); if (r < 0) { *exit_status = EXIT_MEMORY; return log_oom(); } r = dynamic_creds_realize(runtime->dynamic_creds, suggested_paths, &uid, &gid); if (r < 0) { *exit_status = EXIT_USER; if (r == -EILSEQ) return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EOPNOTSUPP), "Failed to update dynamic user credentials: User or group with specified name already exists."); return log_unit_error_errno(unit, r, "Failed to update dynamic user credentials: %m"); } if (!uid_is_valid(uid)) { *exit_status = EXIT_USER; return log_unit_error_errno(unit, SYNTHETIC_ERRNO(ESRCH), "UID validation failed for \""UID_FMT"\"", uid); } if (!gid_is_valid(gid)) { *exit_status = EXIT_USER; return log_unit_error_errno(unit, SYNTHETIC_ERRNO(ESRCH), "GID validation failed for \""GID_FMT"\"", gid); } if (runtime->dynamic_creds->user) username = runtime->dynamic_creds->user->name; } else { r = get_fixed_user(context, &username, &uid, &gid, &home, &shell); if (r < 0) { *exit_status = EXIT_USER; return log_unit_error_errno(unit, r, "Failed to determine user credentials: %m"); } r = get_fixed_group(context, &groupname, &gid); if (r < 0) { *exit_status = EXIT_GROUP; return log_unit_error_errno(unit, r, "Failed to determine group credentials: %m"); } } /* Initialize user supplementary groups and get SupplementaryGroups= ones */ r = get_supplementary_groups(context, username, groupname, gid, &supplementary_gids, &ngids); if (r < 0) { *exit_status = EXIT_GROUP; return log_unit_error_errno(unit, r, "Failed to determine supplementary groups: %m"); } r = send_user_lookup(unit, user_lookup_fd, uid, gid); if (r < 0) { *exit_status = EXIT_USER; return log_unit_error_errno(unit, r, "Failed to send user credentials to PID1: %m"); } user_lookup_fd = safe_close(user_lookup_fd); r = acquire_home(context, uid, &home, &home_buffer); if (r < 0) { *exit_status = EXIT_CHDIR; return log_unit_error_errno(unit, r, "Failed to determine $HOME for user: %m"); } /* If a socket is connected to STDIN/STDOUT/STDERR, we must drop O_NONBLOCK */ if (socket_fd >= 0) (void) fd_nonblock(socket_fd, false); /* Journald will try to look-up our cgroup in order to populate _SYSTEMD_CGROUP and _SYSTEMD_UNIT fields. * Hence we need to migrate to the target cgroup from init.scope before connecting to journald */ if (params->cgroup_path) { _cleanup_free_ char *p = NULL; r = exec_parameters_get_cgroup_path(params, cgroup_context, &p); if (r < 0) { *exit_status = EXIT_CGROUP; return log_unit_error_errno(unit, r, "Failed to acquire cgroup path: %m"); } r = cg_attach_everywhere(params->cgroup_supported, p, 0, NULL, NULL); if (r == -EUCLEAN) { *exit_status = EXIT_CGROUP; return log_unit_error_errno(unit, r, "Failed to attach process to cgroup %s " "because the cgroup or one of its parents or " "siblings is in the threaded mode: %m", p); } if (r < 0) { *exit_status = EXIT_CGROUP; return log_unit_error_errno(unit, r, "Failed to attach to cgroup %s: %m", p); } } if (context->network_namespace_path && runtime && runtime->shared && runtime->shared->netns_storage_socket[0] >= 0) { r = open_shareable_ns_path(runtime->shared->netns_storage_socket, context->network_namespace_path, CLONE_NEWNET); if (r < 0) { *exit_status = EXIT_NETWORK; return log_unit_error_errno(unit, r, "Failed to open network namespace path %s: %m", context->network_namespace_path); } } if (context->ipc_namespace_path && runtime && runtime->shared && runtime->shared->ipcns_storage_socket[0] >= 0) { r = open_shareable_ns_path(runtime->shared->ipcns_storage_socket, context->ipc_namespace_path, CLONE_NEWIPC); if (r < 0) { *exit_status = EXIT_NAMESPACE; return log_unit_error_errno(unit, r, "Failed to open IPC namespace path %s: %m", context->ipc_namespace_path); } } r = setup_input(context, params, socket_fd, named_iofds); if (r < 0) { *exit_status = EXIT_STDIN; return log_unit_error_errno(unit, r, "Failed to set up standard input: %m"); } r = setup_output(unit, context, params, STDOUT_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino); if (r < 0) { *exit_status = EXIT_STDOUT; return log_unit_error_errno(unit, r, "Failed to set up standard output: %m"); } r = setup_output(unit, context, params, STDERR_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino); if (r < 0) { *exit_status = EXIT_STDERR; return log_unit_error_errno(unit, r, "Failed to set up standard error output: %m"); } if (context->oom_score_adjust_set) { /* When we can't make this change due to EPERM, then let's silently skip over it. User namespaces * prohibit write access to this file, and we shouldn't trip up over that. */ r = set_oom_score_adjust(context->oom_score_adjust); if (ERRNO_IS_PRIVILEGE(r)) log_unit_debug_errno(unit, r, "Failed to adjust OOM setting, assuming containerized execution, ignoring: %m"); else if (r < 0) { *exit_status = EXIT_OOM_ADJUST; return log_unit_error_errno(unit, r, "Failed to adjust OOM setting: %m"); } } if (context->coredump_filter_set) { r = set_coredump_filter(context->coredump_filter); if (ERRNO_IS_PRIVILEGE(r)) log_unit_debug_errno(unit, r, "Failed to adjust coredump_filter, ignoring: %m"); else if (r < 0) return log_unit_error_errno(unit, r, "Failed to adjust coredump_filter: %m"); } if (context->nice_set) { r = setpriority_closest(context->nice); if (r < 0) return log_unit_error_errno(unit, r, "Failed to set up process scheduling priority (nice level): %m"); } if (context->cpu_sched_set) { struct sched_param param = { .sched_priority = context->cpu_sched_priority, }; r = sched_setscheduler(0, context->cpu_sched_policy | (context->cpu_sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0), ¶m); if (r < 0) { *exit_status = EXIT_SETSCHEDULER; return log_unit_error_errno(unit, errno, "Failed to set up CPU scheduling: %m"); } } if (context->cpu_affinity_from_numa || context->cpu_set.set) { _cleanup_(cpu_set_reset) CPUSet converted_cpu_set = {}; const CPUSet *cpu_set; if (context->cpu_affinity_from_numa) { r = exec_context_cpu_affinity_from_numa(context, &converted_cpu_set); if (r < 0) { *exit_status = EXIT_CPUAFFINITY; return log_unit_error_errno(unit, r, "Failed to derive CPU affinity mask from NUMA mask: %m"); } cpu_set = &converted_cpu_set; } else cpu_set = &context->cpu_set; if (sched_setaffinity(0, cpu_set->allocated, cpu_set->set) < 0) { *exit_status = EXIT_CPUAFFINITY; return log_unit_error_errno(unit, errno, "Failed to set up CPU affinity: %m"); } } if (mpol_is_valid(numa_policy_get_type(&context->numa_policy))) { r = apply_numa_policy(&context->numa_policy); if (r < 0) { if (ERRNO_IS_NOT_SUPPORTED(r)) log_unit_debug_errno(unit, r, "NUMA support not available, ignoring."); else { *exit_status = EXIT_NUMA_POLICY; return log_unit_error_errno(unit, r, "Failed to set NUMA memory policy: %m"); } } } if (context->ioprio_set) if (ioprio_set(IOPRIO_WHO_PROCESS, 0, context->ioprio) < 0) { *exit_status = EXIT_IOPRIO; return log_unit_error_errno(unit, errno, "Failed to set up IO scheduling priority: %m"); } if (context->timer_slack_nsec != NSEC_INFINITY) if (prctl(PR_SET_TIMERSLACK, context->timer_slack_nsec) < 0) { *exit_status = EXIT_TIMERSLACK; return log_unit_error_errno(unit, errno, "Failed to set up timer slack: %m"); } if (context->personality != PERSONALITY_INVALID) { r = safe_personality(context->personality); if (r < 0) { *exit_status = EXIT_PERSONALITY; return log_unit_error_errno(unit, r, "Failed to set up execution domain (personality): %m"); } } if (context->utmp_id) { const char *line = context->tty_path ? (path_startswith(context->tty_path, "/dev/") ?: context->tty_path) : NULL; utmp_put_init_process(context->utmp_id, getpid_cached(), getsid(0), line, context->utmp_mode == EXEC_UTMP_INIT ? INIT_PROCESS : context->utmp_mode == EXEC_UTMP_LOGIN ? LOGIN_PROCESS : USER_PROCESS, username); } if (uid_is_valid(uid)) { r = chown_terminal(STDIN_FILENO, uid); if (r < 0) { *exit_status = EXIT_STDIN; return log_unit_error_errno(unit, r, "Failed to change ownership of terminal: %m"); } } if (params->cgroup_path) { /* If delegation is enabled we'll pass ownership of the cgroup to the user of the new process. On cgroup v1 * this is only about systemd's own hierarchy, i.e. not the controller hierarchies, simply because that's not * safe. On cgroup v2 there's only one hierarchy anyway, and delegation is safe there, hence in that case only * touch a single hierarchy too. */ if (params->flags & EXEC_CGROUP_DELEGATE) { _cleanup_free_ char *p = NULL; r = cg_set_access(SYSTEMD_CGROUP_CONTROLLER, params->cgroup_path, uid, gid); if (r < 0) { *exit_status = EXIT_CGROUP; return log_unit_error_errno(unit, r, "Failed to adjust control group access: %m"); } r = exec_parameters_get_cgroup_path(params, cgroup_context, &p); if (r < 0) { *exit_status = EXIT_CGROUP; return log_unit_error_errno(unit, r, "Failed to acquire cgroup path: %m"); } if (r > 0) { r = cg_set_access_recursive(SYSTEMD_CGROUP_CONTROLLER, p, uid, gid); if (r < 0) { *exit_status = EXIT_CGROUP; return log_unit_error_errno(unit, r, "Failed to adjust control subgroup access: %m"); } } } if (cgroup_context && cg_unified() > 0 && is_pressure_supported() > 0) { if (cgroup_context_want_memory_pressure(cgroup_context)) { r = cg_get_path("memory", params->cgroup_path, "memory.pressure", &memory_pressure_path); if (r < 0) { *exit_status = EXIT_MEMORY; return log_oom(); } r = chmod_and_chown(memory_pressure_path, 0644, uid, gid); if (r < 0) { log_unit_full_errno(unit, r == -ENOENT || ERRNO_IS_PRIVILEGE(r) ? LOG_DEBUG : LOG_WARNING, r, "Failed to adjust ownership of '%s', ignoring: %m", memory_pressure_path); memory_pressure_path = mfree(memory_pressure_path); } } else if (cgroup_context->memory_pressure_watch == CGROUP_PRESSURE_WATCH_OFF) { memory_pressure_path = strdup("/dev/null"); /* /dev/null is explicit indicator for turning of memory pressure watch */ if (!memory_pressure_path) { *exit_status = EXIT_MEMORY; return log_oom(); } } } } needs_mount_namespace = exec_needs_mount_namespace(context, params, runtime); for (ExecDirectoryType dt = 0; dt < _EXEC_DIRECTORY_TYPE_MAX; dt++) { r = setup_exec_directory(context, params, uid, gid, dt, needs_mount_namespace, exit_status); if (r < 0) return log_unit_error_errno(unit, r, "Failed to set up special execution directory in %s: %m", params->prefix[dt]); } if (FLAGS_SET(params->flags, EXEC_WRITE_CREDENTIALS)) { r = setup_credentials(context, params, unit->id, uid); if (r < 0) { *exit_status = EXIT_CREDENTIALS; return log_unit_error_errno(unit, r, "Failed to set up credentials: %m"); } } r = build_environment( unit, context, params, cgroup_context, n_fds, fdnames, home, username, shell, journal_stream_dev, journal_stream_ino, memory_pressure_path, &our_env); if (r < 0) { *exit_status = EXIT_MEMORY; return log_oom(); } r = build_pass_environment(context, &pass_env); if (r < 0) { *exit_status = EXIT_MEMORY; return log_oom(); } /* The $PATH variable is set to the default path in params->environment. However, this is overridden * if user-specified fields have $PATH set. The intention is to also override $PATH if the unit does * not specify PATH but the unit has ExecSearchPath. */ if (!strv_isempty(context->exec_search_path)) { _cleanup_free_ char *joined = NULL; joined = strv_join(context->exec_search_path, ":"); if (!joined) { *exit_status = EXIT_MEMORY; return log_oom(); } r = strv_env_assign(&joined_exec_search_path, "PATH", joined); if (r < 0) { *exit_status = EXIT_MEMORY; return log_oom(); } } accum_env = strv_env_merge(params->environment, our_env, joined_exec_search_path, pass_env, context->environment, files_env); if (!accum_env) { *exit_status = EXIT_MEMORY; return log_oom(); } accum_env = strv_env_clean(accum_env); (void) umask(context->umask); r = setup_keyring(unit, context, params, uid, gid); if (r < 0) { *exit_status = EXIT_KEYRING; return log_unit_error_errno(unit, r, "Failed to set up kernel keyring: %m"); } /* We need sandboxing if the caller asked us to apply it and the command isn't explicitly excepted * from it. */ needs_sandboxing = (params->flags & EXEC_APPLY_SANDBOXING) && !(command->flags & EXEC_COMMAND_FULLY_PRIVILEGED); /* We need the ambient capability hack, if the caller asked us to apply it and the command is marked * for it, and the kernel doesn't actually support ambient caps. */ needs_ambient_hack = (params->flags & EXEC_APPLY_SANDBOXING) && (command->flags & EXEC_COMMAND_AMBIENT_MAGIC) && !ambient_capabilities_supported(); /* We need setresuid() if the caller asked us to apply sandboxing and the command isn't explicitly * excepted from either whole sandboxing or just setresuid() itself, and the ambient hack is not * desired. */ if (needs_ambient_hack) needs_setuid = false; else needs_setuid = (params->flags & EXEC_APPLY_SANDBOXING) && !(command->flags & (EXEC_COMMAND_FULLY_PRIVILEGED|EXEC_COMMAND_NO_SETUID)); uint64_t capability_ambient_set = context->capability_ambient_set; if (needs_sandboxing) { /* MAC enablement checks need to be done before a new mount ns is created, as they rely on * /sys being present. The actual MAC context application will happen later, as late as * possible, to avoid impacting our own code paths. */ #if HAVE_SELINUX use_selinux = mac_selinux_use(); #endif #if ENABLE_SMACK use_smack = mac_smack_use(); #endif #if HAVE_APPARMOR use_apparmor = mac_apparmor_use(); #endif } if (needs_sandboxing) { int which_failed; /* Let's set the resource limits before we call into PAM, so that pam_limits wins over what * is set here. (See below.) */ r = setrlimit_closest_all((const struct rlimit* const *) context->rlimit, &which_failed); if (r < 0) { *exit_status = EXIT_LIMITS; return log_unit_error_errno(unit, r, "Failed to adjust resource limit RLIMIT_%s: %m", rlimit_to_string(which_failed)); } } if (needs_setuid && context->pam_name && username) { /* Let's call into PAM after we set up our own idea of resource limits to that pam_limits * wins here. (See above.) */ /* All fds passed in the fds array will be closed in the pam child process. */ r = setup_pam(context->pam_name, username, uid, gid, context->tty_path, &accum_env, fds, n_fds); if (r < 0) { *exit_status = EXIT_PAM; return log_unit_error_errno(unit, r, "Failed to set up PAM session: %m"); } if (ambient_capabilities_supported()) { uint64_t ambient_after_pam; /* PAM modules might have set some ambient caps. Query them here and merge them into * the caps we want to set in the end, so that we don't end up unsetting them. */ r = capability_get_ambient(&ambient_after_pam); if (r < 0) { *exit_status = EXIT_CAPABILITIES; return log_unit_error_errno(unit, r, "Failed to query ambient caps: %m"); } capability_ambient_set |= ambient_after_pam; } ngids_after_pam = getgroups_alloc(&gids_after_pam); if (ngids_after_pam < 0) { *exit_status = EXIT_MEMORY; return log_unit_error_errno(unit, ngids_after_pam, "Failed to obtain groups after setting up PAM: %m"); } } if (needs_sandboxing && exec_context_need_unprivileged_private_users(context, unit->manager)) { /* If we're unprivileged, set up the user namespace first to enable use of the other namespaces. * Users with CAP_SYS_ADMIN can set up user namespaces last because they will be able to * set up the all of the other namespaces (i.e. network, mount, UTS) without a user namespace. */ r = setup_private_users(saved_uid, saved_gid, uid, gid); /* If it was requested explicitly and we can't set it up, fail early. Otherwise, continue and let * the actual requested operations fail (or silently continue). */ if (r < 0 && context->private_users) { *exit_status = EXIT_USER; return log_unit_error_errno(unit, r, "Failed to set up user namespacing for unprivileged user: %m"); } if (r < 0) log_unit_info_errno(unit, r, "Failed to set up user namespacing for unprivileged user, ignoring: %m"); else userns_set_up = true; } if (exec_needs_network_namespace(context) && runtime && runtime->shared && runtime->shared->netns_storage_socket[0] >= 0) { if (ns_type_supported(NAMESPACE_NET)) { r = setup_shareable_ns(runtime->shared->netns_storage_socket, CLONE_NEWNET); if (r < 0) { if (ERRNO_IS_PRIVILEGE(r)) log_unit_warning_errno(unit, r, "PrivateNetwork=yes is configured, but network namespace setup failed, ignoring: %m"); else { *exit_status = EXIT_NETWORK; return log_unit_error_errno(unit, r, "Failed to set up network namespacing: %m"); } } } else if (context->network_namespace_path) { *exit_status = EXIT_NETWORK; return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EOPNOTSUPP), "NetworkNamespacePath= is not supported, refusing."); } else log_unit_warning(unit, "PrivateNetwork=yes is configured, but the kernel does not support network namespaces, ignoring."); } if (exec_needs_ipc_namespace(context) && runtime && runtime->shared && runtime->shared->ipcns_storage_socket[0] >= 0) { if (ns_type_supported(NAMESPACE_IPC)) { r = setup_shareable_ns(runtime->shared->ipcns_storage_socket, CLONE_NEWIPC); if (r == -EPERM) log_unit_warning_errno(unit, r, "PrivateIPC=yes is configured, but IPC namespace setup failed, ignoring: %m"); else if (r < 0) { *exit_status = EXIT_NAMESPACE; return log_unit_error_errno(unit, r, "Failed to set up IPC namespacing: %m"); } } else if (context->ipc_namespace_path) { *exit_status = EXIT_NAMESPACE; return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EOPNOTSUPP), "IPCNamespacePath= is not supported, refusing."); } else log_unit_warning(unit, "PrivateIPC=yes is configured, but the kernel does not support IPC namespaces, ignoring."); } if (needs_mount_namespace) { _cleanup_free_ char *error_path = NULL; r = apply_mount_namespace(unit, command->flags, context, params, runtime, memory_pressure_path, &error_path); if (r < 0) { *exit_status = EXIT_NAMESPACE; return log_unit_error_errno(unit, r, "Failed to set up mount namespacing%s%s: %m", error_path ? ": " : "", strempty(error_path)); } } if (needs_sandboxing) { r = apply_protect_hostname(unit, context, exit_status); if (r < 0) return r; } /* Drop groups as early as possible. * This needs to be done after PrivateDevices=y setup as device nodes should be owned by the host's root. * For non-root in a userns, devices will be owned by the user/group before the group change, and nobody. */ if (needs_setuid) { _cleanup_free_ gid_t *gids_to_enforce = NULL; int ngids_to_enforce = 0; ngids_to_enforce = merge_gid_lists(supplementary_gids, ngids, gids_after_pam, ngids_after_pam, &gids_to_enforce); if (ngids_to_enforce < 0) { *exit_status = EXIT_MEMORY; return log_unit_error_errno(unit, ngids_to_enforce, "Failed to merge group lists. Group membership might be incorrect: %m"); } r = enforce_groups(gid, gids_to_enforce, ngids_to_enforce); if (r < 0) { *exit_status = EXIT_GROUP; return log_unit_error_errno(unit, r, "Changing group credentials failed: %m"); } } /* If the user namespace was not set up above, try to do it now. * It's preferred to set up the user namespace later (after all other namespaces) so as not to be * restricted by rules pertaining to combining user namespaces with other namespaces (e.g. in the * case of mount namespaces being less privileged when the mount point list is copied from a * different user namespace). */ if (needs_sandboxing && context->private_users && !userns_set_up) { r = setup_private_users(saved_uid, saved_gid, uid, gid); if (r < 0) { *exit_status = EXIT_USER; return log_unit_error_errno(unit, r, "Failed to set up user namespacing: %m"); } } /* Now that the mount namespace has been set up and privileges adjusted, let's look for the thing we * shall execute. */ _cleanup_free_ char *executable = NULL; _cleanup_close_ int executable_fd = -EBADF; r = find_executable_full(command->path, /* root= */ NULL, context->exec_search_path, false, &executable, &executable_fd); if (r < 0) { if (r != -ENOMEM && (command->flags & EXEC_COMMAND_IGNORE_FAILURE)) { log_unit_struct_errno(unit, LOG_INFO, r, "MESSAGE_ID=" SD_MESSAGE_SPAWN_FAILED_STR, LOG_UNIT_INVOCATION_ID(unit), LOG_UNIT_MESSAGE(unit, "Executable %s missing, skipping: %m", command->path), "EXECUTABLE=%s", command->path); return 0; } *exit_status = EXIT_EXEC; return log_unit_struct_errno(unit, LOG_INFO, r, "MESSAGE_ID=" SD_MESSAGE_SPAWN_FAILED_STR, LOG_UNIT_INVOCATION_ID(unit), LOG_UNIT_MESSAGE(unit, "Failed to locate executable %s: %m", command->path), "EXECUTABLE=%s", command->path); } r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, executable_fd, &executable_fd); if (r < 0) { *exit_status = EXIT_FDS; return log_unit_error_errno(unit, r, "Failed to shift fd and set FD_CLOEXEC: %m"); } #if HAVE_SELINUX if (needs_sandboxing && use_selinux && params->selinux_context_net) { int fd = -EBADF; if (socket_fd >= 0) fd = socket_fd; else if (params->n_socket_fds == 1) /* If stdin is not connected to a socket but we are triggered by exactly one socket unit then we * use context from that fd to compute the label. */ fd = params->fds[0]; if (fd >= 0) { r = mac_selinux_get_child_mls_label(fd, executable, context->selinux_context, &mac_selinux_context_net); if (r < 0) { if (!context->selinux_context_ignore) { *exit_status = EXIT_SELINUX_CONTEXT; return log_unit_error_errno(unit, r, "Failed to determine SELinux context: %m"); } log_unit_debug_errno(unit, r, "Failed to determine SELinux context, ignoring: %m"); } } } #endif /* We repeat the fd closing here, to make sure that nothing is leaked from the PAM modules. Note that * we are more aggressive this time, since we don't need socket_fd and the netns and ipcns fds any * more. We do keep exec_fd however, if we have it, since we need to keep it open until the final * execve(). */ r = close_all_fds(keep_fds, n_keep_fds); if (r >= 0) r = shift_fds(fds, n_fds); if (r >= 0) r = flags_fds(fds, n_socket_fds, n_fds, context->non_blocking); if (r < 0) { *exit_status = EXIT_FDS; return log_unit_error_errno(unit, r, "Failed to adjust passed file descriptors: %m"); } /* At this point, the fds we want to pass to the program are all ready and set up, with O_CLOEXEC turned off * and at the right fd numbers. The are no other fds open, with one exception: the exec_fd if it is defined, * and it has O_CLOEXEC set, after all we want it to be closed by the execve(), so that our parent knows we * came this far. */ secure_bits = context->secure_bits; if (needs_sandboxing) { uint64_t bset; /* Set the RTPRIO resource limit to 0, but only if nothing else was explicitly requested. * (Note this is placed after the general resource limit initialization, see above, in order * to take precedence.) */ if (context->restrict_realtime && !context->rlimit[RLIMIT_RTPRIO]) { if (setrlimit(RLIMIT_RTPRIO, &RLIMIT_MAKE_CONST(0)) < 0) { *exit_status = EXIT_LIMITS; return log_unit_error_errno(unit, errno, "Failed to adjust RLIMIT_RTPRIO resource limit: %m"); } } #if ENABLE_SMACK /* LSM Smack needs the capability CAP_MAC_ADMIN to change the current execution security context of the * process. This is the latest place before dropping capabilities. Other MAC context are set later. */ if (use_smack) { r = setup_smack(unit->manager, context, executable_fd); if (r < 0 && !context->smack_process_label_ignore) { *exit_status = EXIT_SMACK_PROCESS_LABEL; return log_unit_error_errno(unit, r, "Failed to set SMACK process label: %m"); } } #endif bset = context->capability_bounding_set; /* If the ambient caps hack is enabled (which means the kernel can't do them, and the user asked for * our magic fallback), then let's add some extra caps, so that the service can drop privs of its own, * instead of us doing that */ if (needs_ambient_hack) bset |= (UINT64_C(1) << CAP_SETPCAP) | (UINT64_C(1) << CAP_SETUID) | (UINT64_C(1) << CAP_SETGID); if (!cap_test_all(bset)) { r = capability_bounding_set_drop(bset, /* right_now= */ false); if (r < 0) { *exit_status = EXIT_CAPABILITIES; return log_unit_error_errno(unit, r, "Failed to drop capabilities: %m"); } } /* Ambient capabilities are cleared during setresuid() (in enforce_user()) even with * keep-caps set. * * To be able to raise the ambient capabilities after setresuid() they have to be added to * the inherited set and keep caps has to be set (done in enforce_user()). After setresuid() * the ambient capabilities can be raised as they are present in the permitted and * inhertiable set. However it is possible that someone wants to set ambient capabilities * without changing the user, so we also set the ambient capabilities here. * * The requested ambient capabilities are raised in the inheritable set if the second * argument is true. */ if (!needs_ambient_hack) { r = capability_ambient_set_apply(capability_ambient_set, /* also_inherit= */ true); if (r < 0) { *exit_status = EXIT_CAPABILITIES; return log_unit_error_errno(unit, r, "Failed to apply ambient capabilities (before UID change): %m"); } } } /* chroot to root directory first, before we lose the ability to chroot */ r = apply_root_directory(context, params, needs_mount_namespace, exit_status); if (r < 0) return log_unit_error_errno(unit, r, "Chrooting to the requested root directory failed: %m"); if (needs_setuid) { if (uid_is_valid(uid)) { r = enforce_user(context, uid, capability_ambient_set); if (r < 0) { *exit_status = EXIT_USER; return log_unit_error_errno(unit, r, "Failed to change UID to " UID_FMT ": %m", uid); } if (!needs_ambient_hack && capability_ambient_set != 0) { /* Raise the ambient capabilities after user change. */ r = capability_ambient_set_apply(capability_ambient_set, /* also_inherit= */ false); if (r < 0) { *exit_status = EXIT_CAPABILITIES; return log_unit_error_errno(unit, r, "Failed to apply ambient capabilities (after UID change): %m"); } } } } /* Apply working directory here, because the working directory might be on NFS and only the user running * this service might have the correct privilege to change to the working directory */ r = apply_working_directory(context, params, home, exit_status); if (r < 0) return log_unit_error_errno(unit, r, "Changing to the requested working directory failed: %m"); if (needs_sandboxing) { /* Apply other MAC contexts late, but before seccomp syscall filtering, as those should really be last to * influence our own codepaths as little as possible. Moreover, applying MAC contexts usually requires * syscalls that are subject to seccomp filtering, hence should probably be applied before the syscalls * are restricted. */ #if HAVE_SELINUX if (use_selinux) { char *exec_context = mac_selinux_context_net ?: context->selinux_context; if (exec_context) { r = setexeccon(exec_context); if (r < 0) { if (!context->selinux_context_ignore) { *exit_status = EXIT_SELINUX_CONTEXT; return log_unit_error_errno(unit, r, "Failed to change SELinux context to %s: %m", exec_context); } log_unit_debug_errno(unit, r, "Failed to change SELinux context to %s, ignoring: %m", exec_context); } } } #endif #if HAVE_APPARMOR if (use_apparmor && context->apparmor_profile) { r = aa_change_onexec(context->apparmor_profile); if (r < 0 && !context->apparmor_profile_ignore) { *exit_status = EXIT_APPARMOR_PROFILE; return log_unit_error_errno(unit, errno, "Failed to prepare AppArmor profile change to %s: %m", context->apparmor_profile); } } #endif /* PR_GET_SECUREBITS is not privileged, while PR_SET_SECUREBITS is. So to suppress potential * EPERMs we'll try not to call PR_SET_SECUREBITS unless necessary. Setting securebits * requires CAP_SETPCAP. */ if (prctl(PR_GET_SECUREBITS) != secure_bits) { /* CAP_SETPCAP is required to set securebits. This capability is raised into the * effective set here. * * The effective set is overwritten during execve() with the following values: * * - ambient set (for non-root processes) * * - (inheritable | bounding) set for root processes) * * Hence there is no security impact to raise it in the effective set before execve */ r = capability_gain_cap_setpcap(/* return_caps= */ NULL); if (r < 0) { *exit_status = EXIT_CAPABILITIES; return log_unit_error_errno(unit, r, "Failed to gain CAP_SETPCAP for setting secure bits"); } if (prctl(PR_SET_SECUREBITS, secure_bits) < 0) { *exit_status = EXIT_SECUREBITS; return log_unit_error_errno(unit, errno, "Failed to set process secure bits: %m"); } } if (context_has_no_new_privileges(context)) if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) { *exit_status = EXIT_NO_NEW_PRIVILEGES; return log_unit_error_errno(unit, errno, "Failed to disable new privileges: %m"); } #if HAVE_SECCOMP r = apply_address_families(unit, context); if (r < 0) { *exit_status = EXIT_ADDRESS_FAMILIES; return log_unit_error_errno(unit, r, "Failed to restrict address families: %m"); } r = apply_memory_deny_write_execute(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to disable writing to executable memory: %m"); } r = apply_restrict_realtime(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply realtime restrictions: %m"); } r = apply_restrict_suid_sgid(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply SUID/SGID restrictions: %m"); } r = apply_restrict_namespaces(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply namespace restrictions: %m"); } r = apply_protect_sysctl(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply sysctl restrictions: %m"); } r = apply_protect_kernel_modules(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply module loading restrictions: %m"); } r = apply_protect_kernel_logs(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply kernel log restrictions: %m"); } r = apply_protect_clock(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply clock restrictions: %m"); } r = apply_private_devices(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to set up private devices: %m"); } r = apply_syscall_archs(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply syscall architecture restrictions: %m"); } r = apply_lock_personality(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to lock personalities: %m"); } r = apply_syscall_log(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply system call log filters: %m"); } /* This really should remain the last step before the execve(), to make sure our own code is unaffected * by the filter as little as possible. */ r = apply_syscall_filter(unit, context, needs_ambient_hack); if (r < 0) { *exit_status = EXIT_SECCOMP; return log_unit_error_errno(unit, r, "Failed to apply system call filters: %m"); } #endif #if HAVE_LIBBPF r = apply_restrict_filesystems(unit, context); if (r < 0) { *exit_status = EXIT_BPF; return log_unit_error_errno(unit, r, "Failed to restrict filesystems: %m"); } #endif } if (!strv_isempty(context->unset_environment)) { char **ee = NULL; ee = strv_env_delete(accum_env, 1, context->unset_environment); if (!ee) { *exit_status = EXIT_MEMORY; return log_oom(); } strv_free_and_replace(accum_env, ee); } if (!FLAGS_SET(command->flags, EXEC_COMMAND_NO_ENV_EXPAND)) { replaced_argv = replace_env_argv(command->argv, accum_env); if (!replaced_argv) { *exit_status = EXIT_MEMORY; return log_oom(); } final_argv = replaced_argv; } else final_argv = command->argv; log_command_line(unit, "Executing", executable, final_argv); if (exec_fd >= 0) { uint8_t hot = 1; /* We have finished with all our initializations. Let's now let the manager know that. From this point * on, if the manager sees POLLHUP on the exec_fd, then execve() was successful. */ if (write(exec_fd, &hot, sizeof(hot)) < 0) { *exit_status = EXIT_EXEC; return log_unit_error_errno(unit, errno, "Failed to enable exec_fd: %m"); } } r = fexecve_or_execve(executable_fd, executable, final_argv, accum_env); if (exec_fd >= 0) { uint8_t hot = 0; /* The execve() failed. This means the exec_fd is still open. Which means we need to tell the manager * that POLLHUP on it no longer means execve() succeeded. */ if (write(exec_fd, &hot, sizeof(hot)) < 0) { *exit_status = EXIT_EXEC; return log_unit_error_errno(unit, errno, "Failed to disable exec_fd: %m"); } } *exit_status = EXIT_EXEC; return log_unit_error_errno(unit, r, "Failed to execute %s: %m", executable); } static int exec_context_load_environment(const Unit *unit, const ExecContext *c, char ***l); static int exec_context_named_iofds(const ExecContext *c, const ExecParameters *p, int named_iofds[static 3]); int exec_spawn(Unit *unit, ExecCommand *command, const ExecContext *context, const ExecParameters *params, ExecRuntime *runtime, const CGroupContext *cgroup_context, pid_t *ret) { int socket_fd, r, named_iofds[3] = { -1, -1, -1 }, *fds = NULL; _cleanup_free_ char *subcgroup_path = NULL; _cleanup_strv_free_ char **files_env = NULL; size_t n_storage_fds = 0, n_socket_fds = 0; pid_t pid; assert(unit); assert(command); assert(context); assert(ret); assert(params); assert(params->fds || (params->n_socket_fds + params->n_storage_fds <= 0)); LOG_CONTEXT_PUSH_UNIT(unit); if (context->std_input == EXEC_INPUT_SOCKET || context->std_output == EXEC_OUTPUT_SOCKET || context->std_error == EXEC_OUTPUT_SOCKET) { if (params->n_socket_fds > 1) return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EINVAL), "Got more than one socket."); if (params->n_socket_fds == 0) return log_unit_error_errno(unit, SYNTHETIC_ERRNO(EINVAL), "Got no socket."); socket_fd = params->fds[0]; } else { socket_fd = -EBADF; fds = params->fds; n_socket_fds = params->n_socket_fds; n_storage_fds = params->n_storage_fds; } r = exec_context_named_iofds(context, params, named_iofds); if (r < 0) return log_unit_error_errno(unit, r, "Failed to load a named file descriptor: %m"); r = exec_context_load_environment(unit, context, &files_env); if (r < 0) return log_unit_error_errno(unit, r, "Failed to load environment files: %m"); /* Fork with up-to-date SELinux label database, so the child inherits the up-to-date db and, until the next SELinux policy changes, we save further reloads in future children. */ mac_selinux_maybe_reload(); /* We won't know the real executable path until we create the mount namespace in the child, but we want to log from the parent, so we use the possibly inaccurate path here. */ log_command_line(unit, "About to execute", command->path, command->argv); if (params->cgroup_path) { r = exec_parameters_get_cgroup_path(params, cgroup_context, &subcgroup_path); if (r < 0) return log_unit_error_errno(unit, r, "Failed to acquire subcgroup path: %m"); if (r > 0) { /* If there's a subcgroup, then let's create it here now (the main cgroup was already * realized by the unit logic) */ r = cg_create(SYSTEMD_CGROUP_CONTROLLER, subcgroup_path); if (r < 0) return log_unit_error_errno(unit, r, "Failed to create subcgroup '%s': %m", subcgroup_path); } } pid = fork(); if (pid < 0) return log_unit_error_errno(unit, errno, "Failed to fork: %m"); if (pid == 0) { int exit_status = EXIT_SUCCESS; r = exec_child(unit, command, context, params, runtime, cgroup_context, socket_fd, named_iofds, fds, n_socket_fds, n_storage_fds, files_env, unit->manager->user_lookup_fds[1], &exit_status); if (r < 0) { const char *status = exit_status_to_string(exit_status, EXIT_STATUS_LIBC | EXIT_STATUS_SYSTEMD); log_unit_struct_errno(unit, LOG_ERR, r, "MESSAGE_ID=" SD_MESSAGE_SPAWN_FAILED_STR, LOG_UNIT_INVOCATION_ID(unit), LOG_UNIT_MESSAGE(unit, "Failed at step %s spawning %s: %m", status, command->path), "EXECUTABLE=%s", command->path); } _exit(exit_status); } log_unit_debug(unit, "Forked %s as "PID_FMT, command->path, pid); /* We add the new process to the cgroup both in the child (so that we can be sure that no user code is ever * executed outside of the cgroup) and in the parent (so that we can be sure that when we kill the cgroup the * process will be killed too). */ if (subcgroup_path) (void) cg_attach(SYSTEMD_CGROUP_CONTROLLER, subcgroup_path, pid); exec_status_start(&command->exec_status, pid); *ret = pid; return 0; } void exec_context_init(ExecContext *c) { assert(c); c->umask = 0022; c->ioprio = IOPRIO_DEFAULT_CLASS_AND_PRIO; c->cpu_sched_policy = SCHED_OTHER; c->syslog_priority = LOG_DAEMON|LOG_INFO; c->syslog_level_prefix = true; c->ignore_sigpipe = true; c->timer_slack_nsec = NSEC_INFINITY; c->personality = PERSONALITY_INVALID; for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) c->directories[t].mode = 0755; c->timeout_clean_usec = USEC_INFINITY; c->capability_bounding_set = CAP_MASK_UNSET; assert_cc(NAMESPACE_FLAGS_INITIAL != NAMESPACE_FLAGS_ALL); c->restrict_namespaces = NAMESPACE_FLAGS_INITIAL; c->log_level_max = -1; #if HAVE_SECCOMP c->syscall_errno = SECCOMP_ERROR_NUMBER_KILL; #endif c->tty_rows = UINT_MAX; c->tty_cols = UINT_MAX; numa_policy_reset(&c->numa_policy); c->private_mounts = -1; } void exec_context_done(ExecContext *c) { assert(c); c->environment = strv_free(c->environment); c->environment_files = strv_free(c->environment_files); c->pass_environment = strv_free(c->pass_environment); c->unset_environment = strv_free(c->unset_environment); rlimit_free_all(c->rlimit); for (size_t l = 0; l < 3; l++) { c->stdio_fdname[l] = mfree(c->stdio_fdname[l]); c->stdio_file[l] = mfree(c->stdio_file[l]); } c->working_directory = mfree(c->working_directory); c->root_directory = mfree(c->root_directory); c->root_image = mfree(c->root_image); c->root_image_options = mount_options_free_all(c->root_image_options); c->root_hash = mfree(c->root_hash); c->root_hash_size = 0; c->root_hash_path = mfree(c->root_hash_path); c->root_hash_sig = mfree(c->root_hash_sig); c->root_hash_sig_size = 0; c->root_hash_sig_path = mfree(c->root_hash_sig_path); c->root_verity = mfree(c->root_verity); c->extension_images = mount_image_free_many(c->extension_images, &c->n_extension_images); c->extension_directories = strv_free(c->extension_directories); c->tty_path = mfree(c->tty_path); c->syslog_identifier = mfree(c->syslog_identifier); c->user = mfree(c->user); c->group = mfree(c->group); c->supplementary_groups = strv_free(c->supplementary_groups); c->pam_name = mfree(c->pam_name); c->read_only_paths = strv_free(c->read_only_paths); c->read_write_paths = strv_free(c->read_write_paths); c->inaccessible_paths = strv_free(c->inaccessible_paths); c->exec_paths = strv_free(c->exec_paths); c->no_exec_paths = strv_free(c->no_exec_paths); c->exec_search_path = strv_free(c->exec_search_path); bind_mount_free_many(c->bind_mounts, c->n_bind_mounts); c->bind_mounts = NULL; c->n_bind_mounts = 0; temporary_filesystem_free_many(c->temporary_filesystems, c->n_temporary_filesystems); c->temporary_filesystems = NULL; c->n_temporary_filesystems = 0; c->mount_images = mount_image_free_many(c->mount_images, &c->n_mount_images); cpu_set_reset(&c->cpu_set); numa_policy_reset(&c->numa_policy); c->utmp_id = mfree(c->utmp_id); c->selinux_context = mfree(c->selinux_context); c->apparmor_profile = mfree(c->apparmor_profile); c->smack_process_label = mfree(c->smack_process_label); c->restrict_filesystems = set_free(c->restrict_filesystems); c->syscall_filter = hashmap_free(c->syscall_filter); c->syscall_archs = set_free(c->syscall_archs); c->address_families = set_free(c->address_families); for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) exec_directory_done(&c->directories[t]); c->log_level_max = -1; exec_context_free_log_extra_fields(c); c->log_filter_allowed_patterns = set_free(c->log_filter_allowed_patterns); c->log_filter_denied_patterns = set_free(c->log_filter_denied_patterns); c->log_ratelimit_interval_usec = 0; c->log_ratelimit_burst = 0; c->stdin_data = mfree(c->stdin_data); c->stdin_data_size = 0; c->network_namespace_path = mfree(c->network_namespace_path); c->ipc_namespace_path = mfree(c->ipc_namespace_path); c->log_namespace = mfree(c->log_namespace); c->load_credentials = hashmap_free(c->load_credentials); c->set_credentials = hashmap_free(c->set_credentials); c->root_image_policy = image_policy_free(c->root_image_policy); c->mount_image_policy = image_policy_free(c->mount_image_policy); c->extension_image_policy = image_policy_free(c->extension_image_policy); } int exec_context_destroy_runtime_directory(const ExecContext *c, const char *runtime_prefix) { assert(c); if (!runtime_prefix) return 0; for (size_t i = 0; i < c->directories[EXEC_DIRECTORY_RUNTIME].n_items; i++) { _cleanup_free_ char *p = NULL; if (exec_directory_is_private(c, EXEC_DIRECTORY_RUNTIME)) p = path_join(runtime_prefix, "private", c->directories[EXEC_DIRECTORY_RUNTIME].items[i].path); else p = path_join(runtime_prefix, c->directories[EXEC_DIRECTORY_RUNTIME].items[i].path); if (!p) return -ENOMEM; /* We execute this synchronously, since we need to be sure this is gone when we start the * service next. */ (void) rm_rf(p, REMOVE_ROOT); STRV_FOREACH(symlink, c->directories[EXEC_DIRECTORY_RUNTIME].items[i].symlinks) { _cleanup_free_ char *symlink_abs = NULL; if (exec_directory_is_private(c, EXEC_DIRECTORY_RUNTIME)) symlink_abs = path_join(runtime_prefix, "private", *symlink); else symlink_abs = path_join(runtime_prefix, *symlink); if (!symlink_abs) return -ENOMEM; (void) unlink(symlink_abs); } } return 0; } int exec_context_destroy_credentials(const ExecContext *c, const char *runtime_prefix, const char *unit) { _cleanup_free_ char *p = NULL; assert(c); if (!runtime_prefix || !unit) return 0; p = path_join(runtime_prefix, "credentials", unit); if (!p) return -ENOMEM; /* This is either a tmpfs/ramfs of its own, or a plain directory. Either way, let's first try to * unmount it, and afterwards remove the mount point */ (void) umount2(p, MNT_DETACH|UMOUNT_NOFOLLOW); (void) rm_rf(p, REMOVE_ROOT|REMOVE_CHMOD); return 0; } int exec_context_destroy_mount_ns_dir(Unit *u) { _cleanup_free_ char *p = NULL; if (!u || !MANAGER_IS_SYSTEM(u->manager)) return 0; p = path_join("/run/systemd/propagate/", u->id); if (!p) return -ENOMEM; /* This is only filled transiently (see mount_in_namespace()), should be empty or even non-existent*/ if (rmdir(p) < 0 && errno != ENOENT) log_unit_debug_errno(u, errno, "Unable to remove propagation dir '%s', ignoring: %m", p); return 0; } static void exec_command_done(ExecCommand *c) { assert(c); c->path = mfree(c->path); c->argv = strv_free(c->argv); } void exec_command_done_array(ExecCommand *c, size_t n) { for (size_t i = 0; i < n; i++) exec_command_done(c+i); } ExecCommand* exec_command_free_list(ExecCommand *c) { ExecCommand *i; while ((i = c)) { LIST_REMOVE(command, c, i); exec_command_done(i); free(i); } return NULL; } void exec_command_free_array(ExecCommand **c, size_t n) { for (size_t i = 0; i < n; i++) c[i] = exec_command_free_list(c[i]); } void exec_command_reset_status_array(ExecCommand *c, size_t n) { for (size_t i = 0; i < n; i++) exec_status_reset(&c[i].exec_status); } void exec_command_reset_status_list_array(ExecCommand **c, size_t n) { for (size_t i = 0; i < n; i++) LIST_FOREACH(command, z, c[i]) exec_status_reset(&z->exec_status); } typedef struct InvalidEnvInfo { const Unit *unit; const char *path; } InvalidEnvInfo; static void invalid_env(const char *p, void *userdata) { InvalidEnvInfo *info = userdata; log_unit_error(info->unit, "Ignoring invalid environment assignment '%s': %s", p, info->path); } const char* exec_context_fdname(const ExecContext *c, int fd_index) { assert(c); switch (fd_index) { case STDIN_FILENO: if (c->std_input != EXEC_INPUT_NAMED_FD) return NULL; return c->stdio_fdname[STDIN_FILENO] ?: "stdin"; case STDOUT_FILENO: if (c->std_output != EXEC_OUTPUT_NAMED_FD) return NULL; return c->stdio_fdname[STDOUT_FILENO] ?: "stdout"; case STDERR_FILENO: if (c->std_error != EXEC_OUTPUT_NAMED_FD) return NULL; return c->stdio_fdname[STDERR_FILENO] ?: "stderr"; default: return NULL; } } static int exec_context_named_iofds( const ExecContext *c, const ExecParameters *p, int named_iofds[static 3]) { size_t targets; const char* stdio_fdname[3]; size_t n_fds; assert(c); assert(p); assert(named_iofds); targets = (c->std_input == EXEC_INPUT_NAMED_FD) + (c->std_output == EXEC_OUTPUT_NAMED_FD) + (c->std_error == EXEC_OUTPUT_NAMED_FD); for (size_t i = 0; i < 3; i++) stdio_fdname[i] = exec_context_fdname(c, i); n_fds = p->n_storage_fds + p->n_socket_fds; for (size_t i = 0; i < n_fds && targets > 0; i++) if (named_iofds[STDIN_FILENO] < 0 && c->std_input == EXEC_INPUT_NAMED_FD && stdio_fdname[STDIN_FILENO] && streq(p->fd_names[i], stdio_fdname[STDIN_FILENO])) { named_iofds[STDIN_FILENO] = p->fds[i]; targets--; } else if (named_iofds[STDOUT_FILENO] < 0 && c->std_output == EXEC_OUTPUT_NAMED_FD && stdio_fdname[STDOUT_FILENO] && streq(p->fd_names[i], stdio_fdname[STDOUT_FILENO])) { named_iofds[STDOUT_FILENO] = p->fds[i]; targets--; } else if (named_iofds[STDERR_FILENO] < 0 && c->std_error == EXEC_OUTPUT_NAMED_FD && stdio_fdname[STDERR_FILENO] && streq(p->fd_names[i], stdio_fdname[STDERR_FILENO])) { named_iofds[STDERR_FILENO] = p->fds[i]; targets--; } return targets == 0 ? 0 : -ENOENT; } static int exec_context_load_environment(const Unit *unit, const ExecContext *c, char ***ret) { _cleanup_strv_free_ char **v = NULL; int r; assert(c); assert(ret); STRV_FOREACH(i, c->environment_files) { _cleanup_globfree_ glob_t pglob = {}; bool ignore = false; char *fn = *i; if (fn[0] == '-') { ignore = true; fn++; } if (!path_is_absolute(fn)) { if (ignore) continue; return -EINVAL; } /* Filename supports globbing, take all matching files */ r = safe_glob(fn, 0, &pglob); if (r < 0) { if (ignore) continue; return r; } /* When we don't match anything, -ENOENT should be returned */ assert(pglob.gl_pathc > 0); for (unsigned n = 0; n < pglob.gl_pathc; n++) { _cleanup_strv_free_ char **p = NULL; r = load_env_file(NULL, pglob.gl_pathv[n], &p); if (r < 0) { if (ignore) continue; return r; } /* Log invalid environment variables with filename */ if (p) { InvalidEnvInfo info = { .unit = unit, .path = pglob.gl_pathv[n] }; p = strv_env_clean_with_callback(p, invalid_env, &info); } if (!v) v = TAKE_PTR(p); else { char **m = strv_env_merge(v, p); if (!m) return -ENOMEM; strv_free_and_replace(v, m); } } } *ret = TAKE_PTR(v); return 0; } static bool tty_may_match_dev_console(const char *tty) { _cleanup_free_ char *resolved = NULL; if (!tty) return true; tty = skip_dev_prefix(tty); /* trivial identity? */ if (streq(tty, "console")) return true; if (resolve_dev_console(&resolved) < 0) return true; /* if we could not resolve, assume it may */ /* "tty0" means the active VC, so it may be the same sometimes */ return path_equal(resolved, tty) || (streq(resolved, "tty0") && tty_is_vc(tty)); } static bool exec_context_may_touch_tty(const ExecContext *ec) { assert(ec); return ec->tty_reset || ec->tty_vhangup || ec->tty_vt_disallocate || is_terminal_input(ec->std_input) || is_terminal_output(ec->std_output) || is_terminal_output(ec->std_error); } bool exec_context_may_touch_console(const ExecContext *ec) { return exec_context_may_touch_tty(ec) && tty_may_match_dev_console(exec_context_tty_path(ec)); } static void strv_fprintf(FILE *f, char **l) { assert(f); STRV_FOREACH(g, l) fprintf(f, " %s", *g); } static void strv_dump(FILE* f, const char *prefix, const char *name, char **strv) { assert(f); assert(prefix); assert(name); if (!strv_isempty(strv)) { fprintf(f, "%s%s:", prefix, name); strv_fprintf(f, strv); fputs("\n", f); } } void exec_context_dump(const ExecContext *c, FILE* f, const char *prefix) { int r; assert(c); assert(f); prefix = strempty(prefix); fprintf(f, "%sUMask: %04o\n" "%sWorkingDirectory: %s\n" "%sRootDirectory: %s\n" "%sNonBlocking: %s\n" "%sPrivateTmp: %s\n" "%sPrivateDevices: %s\n" "%sProtectKernelTunables: %s\n" "%sProtectKernelModules: %s\n" "%sProtectKernelLogs: %s\n" "%sProtectClock: %s\n" "%sProtectControlGroups: %s\n" "%sPrivateNetwork: %s\n" "%sPrivateUsers: %s\n" "%sProtectHome: %s\n" "%sProtectSystem: %s\n" "%sMountAPIVFS: %s\n" "%sIgnoreSIGPIPE: %s\n" "%sMemoryDenyWriteExecute: %s\n" "%sRestrictRealtime: %s\n" "%sRestrictSUIDSGID: %s\n" "%sKeyringMode: %s\n" "%sProtectHostname: %s\n" "%sProtectProc: %s\n" "%sProcSubset: %s\n", prefix, c->umask, prefix, empty_to_root(c->working_directory), prefix, empty_to_root(c->root_directory), prefix, yes_no(c->non_blocking), prefix, yes_no(c->private_tmp), prefix, yes_no(c->private_devices), prefix, yes_no(c->protect_kernel_tunables), prefix, yes_no(c->protect_kernel_modules), prefix, yes_no(c->protect_kernel_logs), prefix, yes_no(c->protect_clock), prefix, yes_no(c->protect_control_groups), prefix, yes_no(c->private_network), prefix, yes_no(c->private_users), prefix, protect_home_to_string(c->protect_home), prefix, protect_system_to_string(c->protect_system), prefix, yes_no(exec_context_get_effective_mount_apivfs(c)), prefix, yes_no(c->ignore_sigpipe), prefix, yes_no(c->memory_deny_write_execute), prefix, yes_no(c->restrict_realtime), prefix, yes_no(c->restrict_suid_sgid), prefix, exec_keyring_mode_to_string(c->keyring_mode), prefix, yes_no(c->protect_hostname), prefix, protect_proc_to_string(c->protect_proc), prefix, proc_subset_to_string(c->proc_subset)); if (c->root_image) fprintf(f, "%sRootImage: %s\n", prefix, c->root_image); if (c->root_image_options) { fprintf(f, "%sRootImageOptions:", prefix); LIST_FOREACH(mount_options, o, c->root_image_options) if (!isempty(o->options)) fprintf(f, " %s:%s", partition_designator_to_string(o->partition_designator), o->options); fprintf(f, "\n"); } if (c->root_hash) { _cleanup_free_ char *encoded = NULL; encoded = hexmem(c->root_hash, c->root_hash_size); if (encoded) fprintf(f, "%sRootHash: %s\n", prefix, encoded); } if (c->root_hash_path) fprintf(f, "%sRootHash: %s\n", prefix, c->root_hash_path); if (c->root_hash_sig) { _cleanup_free_ char *encoded = NULL; ssize_t len; len = base64mem(c->root_hash_sig, c->root_hash_sig_size, &encoded); if (len) fprintf(f, "%sRootHashSignature: base64:%s\n", prefix, encoded); } if (c->root_hash_sig_path) fprintf(f, "%sRootHashSignature: %s\n", prefix, c->root_hash_sig_path); if (c->root_verity) fprintf(f, "%sRootVerity: %s\n", prefix, c->root_verity); STRV_FOREACH(e, c->environment) fprintf(f, "%sEnvironment: %s\n", prefix, *e); STRV_FOREACH(e, c->environment_files) fprintf(f, "%sEnvironmentFile: %s\n", prefix, *e); STRV_FOREACH(e, c->pass_environment) fprintf(f, "%sPassEnvironment: %s\n", prefix, *e); STRV_FOREACH(e, c->unset_environment) fprintf(f, "%sUnsetEnvironment: %s\n", prefix, *e); fprintf(f, "%sRuntimeDirectoryPreserve: %s\n", prefix, exec_preserve_mode_to_string(c->runtime_directory_preserve_mode)); for (ExecDirectoryType dt = 0; dt < _EXEC_DIRECTORY_TYPE_MAX; dt++) { fprintf(f, "%s%sMode: %04o\n", prefix, exec_directory_type_to_string(dt), c->directories[dt].mode); for (size_t i = 0; i < c->directories[dt].n_items; i++) { fprintf(f, "%s%s: %s\n", prefix, exec_directory_type_to_string(dt), c->directories[dt].items[i].path); STRV_FOREACH(d, c->directories[dt].items[i].symlinks) fprintf(f, "%s%s: %s:%s\n", prefix, exec_directory_type_symlink_to_string(dt), c->directories[dt].items[i].path, *d); } } fprintf(f, "%sTimeoutCleanSec: %s\n", prefix, FORMAT_TIMESPAN(c->timeout_clean_usec, USEC_PER_SEC)); if (c->nice_set) fprintf(f, "%sNice: %i\n", prefix, c->nice); if (c->oom_score_adjust_set) fprintf(f, "%sOOMScoreAdjust: %i\n", prefix, c->oom_score_adjust); if (c->coredump_filter_set) fprintf(f, "%sCoredumpFilter: 0x%"PRIx64"\n", prefix, c->coredump_filter); for (unsigned i = 0; i < RLIM_NLIMITS; i++) if (c->rlimit[i]) { fprintf(f, "%sLimit%s: " RLIM_FMT "\n", prefix, rlimit_to_string(i), c->rlimit[i]->rlim_max); fprintf(f, "%sLimit%sSoft: " RLIM_FMT "\n", prefix, rlimit_to_string(i), c->rlimit[i]->rlim_cur); } if (c->ioprio_set) { _cleanup_free_ char *class_str = NULL; r = ioprio_class_to_string_alloc(ioprio_prio_class(c->ioprio), &class_str); if (r >= 0) fprintf(f, "%sIOSchedulingClass: %s\n", prefix, class_str); fprintf(f, "%sIOPriority: %d\n", prefix, ioprio_prio_data(c->ioprio)); } if (c->cpu_sched_set) { _cleanup_free_ char *policy_str = NULL; r = sched_policy_to_string_alloc(c->cpu_sched_policy, &policy_str); if (r >= 0) fprintf(f, "%sCPUSchedulingPolicy: %s\n", prefix, policy_str); fprintf(f, "%sCPUSchedulingPriority: %i\n" "%sCPUSchedulingResetOnFork: %s\n", prefix, c->cpu_sched_priority, prefix, yes_no(c->cpu_sched_reset_on_fork)); } if (c->cpu_set.set) { _cleanup_free_ char *affinity = NULL; affinity = cpu_set_to_range_string(&c->cpu_set); fprintf(f, "%sCPUAffinity: %s\n", prefix, affinity); } if (mpol_is_valid(numa_policy_get_type(&c->numa_policy))) { _cleanup_free_ char *nodes = NULL; nodes = cpu_set_to_range_string(&c->numa_policy.nodes); fprintf(f, "%sNUMAPolicy: %s\n", prefix, mpol_to_string(numa_policy_get_type(&c->numa_policy))); fprintf(f, "%sNUMAMask: %s\n", prefix, strnull(nodes)); } if (c->timer_slack_nsec != NSEC_INFINITY) fprintf(f, "%sTimerSlackNSec: "NSEC_FMT "\n", prefix, c->timer_slack_nsec); fprintf(f, "%sStandardInput: %s\n" "%sStandardOutput: %s\n" "%sStandardError: %s\n", prefix, exec_input_to_string(c->std_input), prefix, exec_output_to_string(c->std_output), prefix, exec_output_to_string(c->std_error)); if (c->std_input == EXEC_INPUT_NAMED_FD) fprintf(f, "%sStandardInputFileDescriptorName: %s\n", prefix, c->stdio_fdname[STDIN_FILENO]); if (c->std_output == EXEC_OUTPUT_NAMED_FD) fprintf(f, "%sStandardOutputFileDescriptorName: %s\n", prefix, c->stdio_fdname[STDOUT_FILENO]); if (c->std_error == EXEC_OUTPUT_NAMED_FD) fprintf(f, "%sStandardErrorFileDescriptorName: %s\n", prefix, c->stdio_fdname[STDERR_FILENO]); if (c->std_input == EXEC_INPUT_FILE) fprintf(f, "%sStandardInputFile: %s\n", prefix, c->stdio_file[STDIN_FILENO]); if (c->std_output == EXEC_OUTPUT_FILE) fprintf(f, "%sStandardOutputFile: %s\n", prefix, c->stdio_file[STDOUT_FILENO]); if (c->std_output == EXEC_OUTPUT_FILE_APPEND) fprintf(f, "%sStandardOutputFileToAppend: %s\n", prefix, c->stdio_file[STDOUT_FILENO]); if (c->std_output == EXEC_OUTPUT_FILE_TRUNCATE) fprintf(f, "%sStandardOutputFileToTruncate: %s\n", prefix, c->stdio_file[STDOUT_FILENO]); if (c->std_error == EXEC_OUTPUT_FILE) fprintf(f, "%sStandardErrorFile: %s\n", prefix, c->stdio_file[STDERR_FILENO]); if (c->std_error == EXEC_OUTPUT_FILE_APPEND) fprintf(f, "%sStandardErrorFileToAppend: %s\n", prefix, c->stdio_file[STDERR_FILENO]); if (c->std_error == EXEC_OUTPUT_FILE_TRUNCATE) fprintf(f, "%sStandardErrorFileToTruncate: %s\n", prefix, c->stdio_file[STDERR_FILENO]); if (c->tty_path) fprintf(f, "%sTTYPath: %s\n" "%sTTYReset: %s\n" "%sTTYVHangup: %s\n" "%sTTYVTDisallocate: %s\n" "%sTTYRows: %u\n" "%sTTYColumns: %u\n", prefix, c->tty_path, prefix, yes_no(c->tty_reset), prefix, yes_no(c->tty_vhangup), prefix, yes_no(c->tty_vt_disallocate), prefix, c->tty_rows, prefix, c->tty_cols); if (IN_SET(c->std_output, EXEC_OUTPUT_KMSG, EXEC_OUTPUT_JOURNAL, EXEC_OUTPUT_KMSG_AND_CONSOLE, EXEC_OUTPUT_JOURNAL_AND_CONSOLE) || IN_SET(c->std_error, EXEC_OUTPUT_KMSG, EXEC_OUTPUT_JOURNAL, EXEC_OUTPUT_KMSG_AND_CONSOLE, EXEC_OUTPUT_JOURNAL_AND_CONSOLE)) { _cleanup_free_ char *fac_str = NULL, *lvl_str = NULL; r = log_facility_unshifted_to_string_alloc(c->syslog_priority >> 3, &fac_str); if (r >= 0) fprintf(f, "%sSyslogFacility: %s\n", prefix, fac_str); r = log_level_to_string_alloc(LOG_PRI(c->syslog_priority), &lvl_str); if (r >= 0) fprintf(f, "%sSyslogLevel: %s\n", prefix, lvl_str); } if (c->log_level_max >= 0) { _cleanup_free_ char *t = NULL; (void) log_level_to_string_alloc(c->log_level_max, &t); fprintf(f, "%sLogLevelMax: %s\n", prefix, strna(t)); } if (c->log_ratelimit_interval_usec > 0) fprintf(f, "%sLogRateLimitIntervalSec: %s\n", prefix, FORMAT_TIMESPAN(c->log_ratelimit_interval_usec, USEC_PER_SEC)); if (c->log_ratelimit_burst > 0) fprintf(f, "%sLogRateLimitBurst: %u\n", prefix, c->log_ratelimit_burst); if (!set_isempty(c->log_filter_allowed_patterns) || !set_isempty(c->log_filter_denied_patterns)) { fprintf(f, "%sLogFilterPatterns:", prefix); char *pattern; SET_FOREACH(pattern, c->log_filter_allowed_patterns) fprintf(f, " %s", pattern); SET_FOREACH(pattern, c->log_filter_denied_patterns) fprintf(f, " ~%s", pattern); fputc('\n', f); } for (size_t j = 0; j < c->n_log_extra_fields; j++) { fprintf(f, "%sLogExtraFields: ", prefix); fwrite(c->log_extra_fields[j].iov_base, 1, c->log_extra_fields[j].iov_len, f); fputc('\n', f); } if (c->log_namespace) fprintf(f, "%sLogNamespace: %s\n", prefix, c->log_namespace); if (c->secure_bits) { _cleanup_free_ char *str = NULL; r = secure_bits_to_string_alloc(c->secure_bits, &str); if (r >= 0) fprintf(f, "%sSecure Bits: %s\n", prefix, str); } if (c->capability_bounding_set != CAP_MASK_UNSET) { _cleanup_free_ char *str = NULL; r = capability_set_to_string(c->capability_bounding_set, &str); if (r >= 0) fprintf(f, "%sCapabilityBoundingSet: %s\n", prefix, str); } if (c->capability_ambient_set != 0) { _cleanup_free_ char *str = NULL; r = capability_set_to_string(c->capability_ambient_set, &str); if (r >= 0) fprintf(f, "%sAmbientCapabilities: %s\n", prefix, str); } if (c->user) fprintf(f, "%sUser: %s\n", prefix, c->user); if (c->group) fprintf(f, "%sGroup: %s\n", prefix, c->group); fprintf(f, "%sDynamicUser: %s\n", prefix, yes_no(c->dynamic_user)); strv_dump(f, prefix, "SupplementaryGroups", c->supplementary_groups); if (c->pam_name) fprintf(f, "%sPAMName: %s\n", prefix, c->pam_name); strv_dump(f, prefix, "ReadWritePaths", c->read_write_paths); strv_dump(f, prefix, "ReadOnlyPaths", c->read_only_paths); strv_dump(f, prefix, "InaccessiblePaths", c->inaccessible_paths); strv_dump(f, prefix, "ExecPaths", c->exec_paths); strv_dump(f, prefix, "NoExecPaths", c->no_exec_paths); strv_dump(f, prefix, "ExecSearchPath", c->exec_search_path); for (size_t i = 0; i < c->n_bind_mounts; i++) fprintf(f, "%s%s: %s%s:%s:%s\n", prefix, c->bind_mounts[i].read_only ? "BindReadOnlyPaths" : "BindPaths", c->bind_mounts[i].ignore_enoent ? "-": "", c->bind_mounts[i].source, c->bind_mounts[i].destination, c->bind_mounts[i].recursive ? "rbind" : "norbind"); for (size_t i = 0; i < c->n_temporary_filesystems; i++) { const TemporaryFileSystem *t = c->temporary_filesystems + i; fprintf(f, "%sTemporaryFileSystem: %s%s%s\n", prefix, t->path, isempty(t->options) ? "" : ":", strempty(t->options)); } if (c->utmp_id) fprintf(f, "%sUtmpIdentifier: %s\n", prefix, c->utmp_id); if (c->selinux_context) fprintf(f, "%sSELinuxContext: %s%s\n", prefix, c->selinux_context_ignore ? "-" : "", c->selinux_context); if (c->apparmor_profile) fprintf(f, "%sAppArmorProfile: %s%s\n", prefix, c->apparmor_profile_ignore ? "-" : "", c->apparmor_profile); if (c->smack_process_label) fprintf(f, "%sSmackProcessLabel: %s%s\n", prefix, c->smack_process_label_ignore ? "-" : "", c->smack_process_label); if (c->personality != PERSONALITY_INVALID) fprintf(f, "%sPersonality: %s\n", prefix, strna(personality_to_string(c->personality))); fprintf(f, "%sLockPersonality: %s\n", prefix, yes_no(c->lock_personality)); if (c->syscall_filter) { fprintf(f, "%sSystemCallFilter: ", prefix); if (!c->syscall_allow_list) fputc('~', f); #if HAVE_SECCOMP void *id, *val; bool first = true; HASHMAP_FOREACH_KEY(val, id, c->syscall_filter) { _cleanup_free_ char *name = NULL; const char *errno_name = NULL; int num = PTR_TO_INT(val); if (first) first = false; else fputc(' ', f); name = seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE, PTR_TO_INT(id) - 1); fputs(strna(name), f); if (num >= 0) { errno_name = seccomp_errno_or_action_to_string(num); if (errno_name) fprintf(f, ":%s", errno_name); else fprintf(f, ":%d", num); } } #endif fputc('\n', f); } if (c->syscall_archs) { fprintf(f, "%sSystemCallArchitectures:", prefix); #if HAVE_SECCOMP void *id; SET_FOREACH(id, c->syscall_archs) fprintf(f, " %s", strna(seccomp_arch_to_string(PTR_TO_UINT32(id) - 1))); #endif fputc('\n', f); } if (exec_context_restrict_namespaces_set(c)) { _cleanup_free_ char *s = NULL; r = namespace_flags_to_string(c->restrict_namespaces, &s); if (r >= 0) fprintf(f, "%sRestrictNamespaces: %s\n", prefix, strna(s)); } #if HAVE_LIBBPF if (exec_context_restrict_filesystems_set(c)) { char *fs; SET_FOREACH(fs, c->restrict_filesystems) fprintf(f, "%sRestrictFileSystems: %s\n", prefix, fs); } #endif if (c->network_namespace_path) fprintf(f, "%sNetworkNamespacePath: %s\n", prefix, c->network_namespace_path); if (c->syscall_errno > 0) { fprintf(f, "%sSystemCallErrorNumber: ", prefix); #if HAVE_SECCOMP const char *errno_name = seccomp_errno_or_action_to_string(c->syscall_errno); if (errno_name) fputs(errno_name, f); else fprintf(f, "%d", c->syscall_errno); #endif fputc('\n', f); } for (size_t i = 0; i < c->n_mount_images; i++) { fprintf(f, "%sMountImages: %s%s:%s", prefix, c->mount_images[i].ignore_enoent ? "-": "", c->mount_images[i].source, c->mount_images[i].destination); LIST_FOREACH(mount_options, o, c->mount_images[i].mount_options) fprintf(f, ":%s:%s", partition_designator_to_string(o->partition_designator), strempty(o->options)); fprintf(f, "\n"); } for (size_t i = 0; i < c->n_extension_images; i++) { fprintf(f, "%sExtensionImages: %s%s", prefix, c->extension_images[i].ignore_enoent ? "-": "", c->extension_images[i].source); LIST_FOREACH(mount_options, o, c->extension_images[i].mount_options) fprintf(f, ":%s:%s", partition_designator_to_string(o->partition_designator), strempty(o->options)); fprintf(f, "\n"); } strv_dump(f, prefix, "ExtensionDirectories", c->extension_directories); } bool exec_context_maintains_privileges(const ExecContext *c) { assert(c); /* Returns true if the process forked off would run under * an unchanged UID or as root. */ if (!c->user) return true; if (streq(c->user, "root") || streq(c->user, "0")) return true; return false; } int exec_context_get_effective_ioprio(const ExecContext *c) { int p; assert(c); if (c->ioprio_set) return c->ioprio; p = ioprio_get(IOPRIO_WHO_PROCESS, 0); if (p < 0) return IOPRIO_DEFAULT_CLASS_AND_PRIO; return ioprio_normalize(p); } bool exec_context_get_effective_mount_apivfs(const ExecContext *c) { assert(c); /* Explicit setting wins */ if (c->mount_apivfs_set) return c->mount_apivfs; /* Default to "yes" if root directory or image are specified */ if (exec_context_with_rootfs(c)) return true; return false; } void exec_context_free_log_extra_fields(ExecContext *c) { assert(c); for (size_t l = 0; l < c->n_log_extra_fields; l++) free(c->log_extra_fields[l].iov_base); c->log_extra_fields = mfree(c->log_extra_fields); c->n_log_extra_fields = 0; } void exec_context_revert_tty(ExecContext *c) { _cleanup_close_ int fd = -EBADF; const char *path; struct stat st; int r; assert(c); /* First, reset the TTY (possibly kicking everybody else from the TTY) */ exec_context_tty_reset(c, NULL); /* And then undo what chown_terminal() did earlier. Note that we only do this if we have a path * configured. If the TTY was passed to us as file descriptor we assume the TTY is opened and managed * by whoever passed it to us and thus knows better when and how to chmod()/chown() it back. */ if (!exec_context_may_touch_tty(c)) return; path = exec_context_tty_path(c); if (!path) return; fd = open(path, O_PATH|O_CLOEXEC); if (fd < 0) return (void) log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_WARNING, errno, "Failed to open TTY inode of '%s' to adjust ownership/access mode, ignoring: %m", path); if (fstat(fd, &st) < 0) return (void) log_warning_errno(errno, "Failed to stat TTY '%s', ignoring: %m", path); /* Let's add a superficial check that we only do this for stuff that looks like a TTY. We only check * if things are a character device, since a proper check either means we'd have to open the TTY and * use isatty(), but we'd rather not do that since opening TTYs comes with all kinds of side-effects * and is slow. Or we'd have to hardcode dev_t major information, which we'd rather avoid. Why bother * with this at all? → https://github.com/systemd/systemd/issues/19213 */ if (!S_ISCHR(st.st_mode)) return log_warning("Configured TTY '%s' is not actually a character device, ignoring.", path); r = fchmod_and_chown(fd, TTY_MODE, 0, TTY_GID); if (r < 0) log_warning_errno(r, "Failed to reset TTY ownership/access mode of %s, ignoring: %m", path); } int exec_context_get_clean_directories( ExecContext *c, char **prefix, ExecCleanMask mask, char ***ret) { _cleanup_strv_free_ char **l = NULL; int r; assert(c); assert(prefix); assert(ret); for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) { if (!FLAGS_SET(mask, 1U << t)) continue; if (!prefix[t]) continue; for (size_t i = 0; i < c->directories[t].n_items; i++) { char *j; j = path_join(prefix[t], c->directories[t].items[i].path); if (!j) return -ENOMEM; r = strv_consume(&l, j); if (r < 0) return r; /* Also remove private directories unconditionally. */ if (t != EXEC_DIRECTORY_CONFIGURATION) { j = path_join(prefix[t], "private", c->directories[t].items[i].path); if (!j) return -ENOMEM; r = strv_consume(&l, j); if (r < 0) return r; } STRV_FOREACH(symlink, c->directories[t].items[i].symlinks) { j = path_join(prefix[t], *symlink); if (!j) return -ENOMEM; r = strv_consume(&l, j); if (r < 0) return r; } } } *ret = TAKE_PTR(l); return 0; } int exec_context_get_clean_mask(ExecContext *c, ExecCleanMask *ret) { ExecCleanMask mask = 0; assert(c); assert(ret); for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) if (c->directories[t].n_items > 0) mask |= 1U << t; *ret = mask; return 0; } bool exec_context_has_encrypted_credentials(ExecContext *c) { ExecLoadCredential *load_cred; ExecSetCredential *set_cred; assert(c); HASHMAP_FOREACH(load_cred, c->load_credentials) if (load_cred->encrypted) return true; HASHMAP_FOREACH(set_cred, c->set_credentials) if (set_cred->encrypted) return true; return false; } void exec_status_start(ExecStatus *s, pid_t pid) { assert(s); *s = (ExecStatus) { .pid = pid, }; dual_timestamp_get(&s->start_timestamp); } void exec_status_exit(ExecStatus *s, const ExecContext *context, pid_t pid, int code, int status) { assert(s); if (s->pid != pid) *s = (ExecStatus) { .pid = pid, }; dual_timestamp_get(&s->exit_timestamp); s->code = code; s->status = status; if (context && context->utmp_id) (void) utmp_put_dead_process(context->utmp_id, pid, code, status); } void exec_status_reset(ExecStatus *s) { assert(s); *s = (ExecStatus) {}; } void exec_status_dump(const ExecStatus *s, FILE *f, const char *prefix) { assert(s); assert(f); if (s->pid <= 0) return; prefix = strempty(prefix); fprintf(f, "%sPID: "PID_FMT"\n", prefix, s->pid); if (dual_timestamp_is_set(&s->start_timestamp)) fprintf(f, "%sStart Timestamp: %s\n", prefix, FORMAT_TIMESTAMP(s->start_timestamp.realtime)); if (dual_timestamp_is_set(&s->exit_timestamp)) fprintf(f, "%sExit Timestamp: %s\n" "%sExit Code: %s\n" "%sExit Status: %i\n", prefix, FORMAT_TIMESTAMP(s->exit_timestamp.realtime), prefix, sigchld_code_to_string(s->code), prefix, s->status); } static void exec_command_dump(ExecCommand *c, FILE *f, const char *prefix) { _cleanup_free_ char *cmd = NULL; const char *prefix2; assert(c); assert(f); prefix = strempty(prefix); prefix2 = strjoina(prefix, "\t"); cmd = quote_command_line(c->argv, SHELL_ESCAPE_EMPTY); fprintf(f, "%sCommand Line: %s\n", prefix, strnull(cmd)); exec_status_dump(&c->exec_status, f, prefix2); } void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix) { assert(f); prefix = strempty(prefix); LIST_FOREACH(command, i, c) exec_command_dump(i, f, prefix); } void exec_command_append_list(ExecCommand **l, ExecCommand *e) { ExecCommand *end; assert(l); assert(e); if (*l) { /* It's kind of important, that we keep the order here */ end = LIST_FIND_TAIL(command, *l); LIST_INSERT_AFTER(command, *l, end, e); } else *l = e; } int exec_command_set(ExecCommand *c, const char *path, ...) { va_list ap; char **l, *p; assert(c); assert(path); va_start(ap, path); l = strv_new_ap(path, ap); va_end(ap); if (!l) return -ENOMEM; p = strdup(path); if (!p) { strv_free(l); return -ENOMEM; } free_and_replace(c->path, p); return strv_free_and_replace(c->argv, l); } int exec_command_append(ExecCommand *c, const char *path, ...) { _cleanup_strv_free_ char **l = NULL; va_list ap; int r; assert(c); assert(path); va_start(ap, path); l = strv_new_ap(path, ap); va_end(ap); if (!l) return -ENOMEM; r = strv_extend_strv(&c->argv, l, false); if (r < 0) return r; return 0; } static void *remove_tmpdir_thread(void *p) { _cleanup_free_ char *path = p; (void) rm_rf(path, REMOVE_ROOT|REMOVE_PHYSICAL); return NULL; } static ExecSharedRuntime* exec_shared_runtime_free(ExecSharedRuntime *rt) { if (!rt) return NULL; if (rt->manager) (void) hashmap_remove(rt->manager->exec_shared_runtime_by_id, rt->id); rt->id = mfree(rt->id); rt->tmp_dir = mfree(rt->tmp_dir); rt->var_tmp_dir = mfree(rt->var_tmp_dir); safe_close_pair(rt->netns_storage_socket); safe_close_pair(rt->ipcns_storage_socket); return mfree(rt); } DEFINE_TRIVIAL_UNREF_FUNC(ExecSharedRuntime, exec_shared_runtime, exec_shared_runtime_free); DEFINE_TRIVIAL_CLEANUP_FUNC(ExecSharedRuntime*, exec_shared_runtime_free); ExecSharedRuntime* exec_shared_runtime_destroy(ExecSharedRuntime *rt) { int r; if (!rt) return NULL; assert(rt->n_ref > 0); rt->n_ref--; if (rt->n_ref > 0) return NULL; if (rt->tmp_dir && !streq(rt->tmp_dir, RUN_SYSTEMD_EMPTY)) { log_debug("Spawning thread to nuke %s", rt->tmp_dir); r = asynchronous_job(remove_tmpdir_thread, rt->tmp_dir); if (r < 0) log_warning_errno(r, "Failed to nuke %s: %m", rt->tmp_dir); else rt->tmp_dir = NULL; } if (rt->var_tmp_dir && !streq(rt->var_tmp_dir, RUN_SYSTEMD_EMPTY)) { log_debug("Spawning thread to nuke %s", rt->var_tmp_dir); r = asynchronous_job(remove_tmpdir_thread, rt->var_tmp_dir); if (r < 0) log_warning_errno(r, "Failed to nuke %s: %m", rt->var_tmp_dir); else rt->var_tmp_dir = NULL; } return exec_shared_runtime_free(rt); } static int exec_shared_runtime_allocate(ExecSharedRuntime **ret, const char *id) { _cleanup_free_ char *id_copy = NULL; ExecSharedRuntime *n; assert(ret); id_copy = strdup(id); if (!id_copy) return -ENOMEM; n = new(ExecSharedRuntime, 1); if (!n) return -ENOMEM; *n = (ExecSharedRuntime) { .id = TAKE_PTR(id_copy), .netns_storage_socket = PIPE_EBADF, .ipcns_storage_socket = PIPE_EBADF, }; *ret = n; return 0; } static int exec_shared_runtime_add( Manager *m, const char *id, char **tmp_dir, char **var_tmp_dir, int netns_storage_socket[2], int ipcns_storage_socket[2], ExecSharedRuntime **ret) { _cleanup_(exec_shared_runtime_freep) ExecSharedRuntime *rt = NULL; int r; assert(m); assert(id); /* tmp_dir, var_tmp_dir, {net,ipc}ns_storage_socket fds are donated on success */ r = exec_shared_runtime_allocate(&rt, id); if (r < 0) return r; r = hashmap_ensure_put(&m->exec_shared_runtime_by_id, &string_hash_ops, rt->id, rt); if (r < 0) return r; assert(!!rt->tmp_dir == !!rt->var_tmp_dir); /* We require both to be set together */ rt->tmp_dir = TAKE_PTR(*tmp_dir); rt->var_tmp_dir = TAKE_PTR(*var_tmp_dir); if (netns_storage_socket) { rt->netns_storage_socket[0] = TAKE_FD(netns_storage_socket[0]); rt->netns_storage_socket[1] = TAKE_FD(netns_storage_socket[1]); } if (ipcns_storage_socket) { rt->ipcns_storage_socket[0] = TAKE_FD(ipcns_storage_socket[0]); rt->ipcns_storage_socket[1] = TAKE_FD(ipcns_storage_socket[1]); } rt->manager = m; if (ret) *ret = rt; /* do not remove created ExecSharedRuntime object when the operation succeeds. */ TAKE_PTR(rt); return 0; } static int exec_shared_runtime_make( Manager *m, const ExecContext *c, const char *id, ExecSharedRuntime **ret) { _cleanup_(namespace_cleanup_tmpdirp) char *tmp_dir = NULL, *var_tmp_dir = NULL; _cleanup_close_pair_ int netns_storage_socket[2] = PIPE_EBADF, ipcns_storage_socket[2] = PIPE_EBADF; int r; assert(m); assert(c); assert(id); /* It is not necessary to create ExecSharedRuntime object. */ if (!exec_needs_network_namespace(c) && !exec_needs_ipc_namespace(c) && !c->private_tmp) { *ret = NULL; return 0; } if (c->private_tmp && !(prefixed_path_strv_contains(c->inaccessible_paths, "/tmp") && (prefixed_path_strv_contains(c->inaccessible_paths, "/var/tmp") || prefixed_path_strv_contains(c->inaccessible_paths, "/var")))) { r = setup_tmp_dirs(id, &tmp_dir, &var_tmp_dir); if (r < 0) return r; } if (exec_needs_network_namespace(c)) { if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, netns_storage_socket) < 0) return -errno; } if (exec_needs_ipc_namespace(c)) { if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, ipcns_storage_socket) < 0) return -errno; } r = exec_shared_runtime_add(m, id, &tmp_dir, &var_tmp_dir, netns_storage_socket, ipcns_storage_socket, ret); if (r < 0) return r; return 1; } int exec_shared_runtime_acquire(Manager *m, const ExecContext *c, const char *id, bool create, ExecSharedRuntime **ret) { ExecSharedRuntime *rt; int r; assert(m); assert(id); assert(ret); rt = hashmap_get(m->exec_shared_runtime_by_id, id); if (rt) /* We already have an ExecSharedRuntime object, let's increase the ref count and reuse it */ goto ref; if (!create) { *ret = NULL; return 0; } /* If not found, then create a new object. */ r = exec_shared_runtime_make(m, c, id, &rt); if (r < 0) return r; if (r == 0) { /* When r == 0, it is not necessary to create ExecSharedRuntime object. */ *ret = NULL; return 0; } ref: /* increment reference counter. */ rt->n_ref++; *ret = rt; return 1; } int exec_shared_runtime_serialize(const Manager *m, FILE *f, FDSet *fds) { ExecSharedRuntime *rt; assert(m); assert(f); assert(fds); HASHMAP_FOREACH(rt, m->exec_shared_runtime_by_id) { fprintf(f, "exec-runtime=%s", rt->id); if (rt->tmp_dir) fprintf(f, " tmp-dir=%s", rt->tmp_dir); if (rt->var_tmp_dir) fprintf(f, " var-tmp-dir=%s", rt->var_tmp_dir); if (rt->netns_storage_socket[0] >= 0) { int copy; copy = fdset_put_dup(fds, rt->netns_storage_socket[0]); if (copy < 0) return copy; fprintf(f, " netns-socket-0=%i", copy); } if (rt->netns_storage_socket[1] >= 0) { int copy; copy = fdset_put_dup(fds, rt->netns_storage_socket[1]); if (copy < 0) return copy; fprintf(f, " netns-socket-1=%i", copy); } if (rt->ipcns_storage_socket[0] >= 0) { int copy; copy = fdset_put_dup(fds, rt->ipcns_storage_socket[0]); if (copy < 0) return copy; fprintf(f, " ipcns-socket-0=%i", copy); } if (rt->ipcns_storage_socket[1] >= 0) { int copy; copy = fdset_put_dup(fds, rt->ipcns_storage_socket[1]); if (copy < 0) return copy; fprintf(f, " ipcns-socket-1=%i", copy); } fputc('\n', f); } return 0; } int exec_shared_runtime_deserialize_compat(Unit *u, const char *key, const char *value, FDSet *fds) { _cleanup_(exec_shared_runtime_freep) ExecSharedRuntime *rt_create = NULL; ExecSharedRuntime *rt; int r; /* This is for the migration from old (v237 or earlier) deserialization text. * Due to the bug #7790, this may not work with the units that use JoinsNamespaceOf=. * Even if the ExecSharedRuntime object originally created by the other unit, we cannot judge * so or not from the serialized text, then we always creates a new object owned by this. */ assert(u); assert(key); assert(value); /* Manager manages ExecSharedRuntime objects by the unit id. * So, we omit the serialized text when the unit does not have id (yet?)... */ if (isempty(u->id)) { log_unit_debug(u, "Invocation ID not found. Dropping runtime parameter."); return 0; } if (hashmap_ensure_allocated(&u->manager->exec_shared_runtime_by_id, &string_hash_ops) < 0) return log_oom(); rt = hashmap_get(u->manager->exec_shared_runtime_by_id, u->id); if (!rt) { if (exec_shared_runtime_allocate(&rt_create, u->id) < 0) return log_oom(); rt = rt_create; } if (streq(key, "tmp-dir")) { if (free_and_strdup_warn(&rt->tmp_dir, value) < 0) return -ENOMEM; } else if (streq(key, "var-tmp-dir")) { if (free_and_strdup_warn(&rt->var_tmp_dir, value) < 0) return -ENOMEM; } else if (streq(key, "netns-socket-0")) { int fd; if ((fd = parse_fd(value)) < 0 || !fdset_contains(fds, fd)) { log_unit_debug(u, "Failed to parse netns socket value: %s", value); return 0; } safe_close(rt->netns_storage_socket[0]); rt->netns_storage_socket[0] = fdset_remove(fds, fd); } else if (streq(key, "netns-socket-1")) { int fd; if ((fd = parse_fd(value)) < 0 || !fdset_contains(fds, fd)) { log_unit_debug(u, "Failed to parse netns socket value: %s", value); return 0; } safe_close(rt->netns_storage_socket[1]); rt->netns_storage_socket[1] = fdset_remove(fds, fd); } else return 0; /* If the object is newly created, then put it to the hashmap which manages ExecSharedRuntime objects. */ if (rt_create) { r = hashmap_put(u->manager->exec_shared_runtime_by_id, rt_create->id, rt_create); if (r < 0) { log_unit_debug_errno(u, r, "Failed to put runtime parameter to manager's storage: %m"); return 0; } rt_create->manager = u->manager; /* Avoid cleanup */ TAKE_PTR(rt_create); } return 1; } int exec_shared_runtime_deserialize_one(Manager *m, const char *value, FDSet *fds) { _cleanup_free_ char *tmp_dir = NULL, *var_tmp_dir = NULL; char *id = NULL; int r, netns_fdpair[] = {-1, -1}, ipcns_fdpair[] = {-1, -1}; const char *p, *v = ASSERT_PTR(value); size_t n; assert(m); assert(fds); n = strcspn(v, " "); id = strndupa_safe(v, n); if (v[n] != ' ') goto finalize; p = v + n + 1; v = startswith(p, "tmp-dir="); if (v) { n = strcspn(v, " "); tmp_dir = strndup(v, n); if (!tmp_dir) return log_oom(); if (v[n] != ' ') goto finalize; p = v + n + 1; } v = startswith(p, "var-tmp-dir="); if (v) { n = strcspn(v, " "); var_tmp_dir = strndup(v, n); if (!var_tmp_dir) return log_oom(); if (v[n] != ' ') goto finalize; p = v + n + 1; } v = startswith(p, "netns-socket-0="); if (v) { char *buf; n = strcspn(v, " "); buf = strndupa_safe(v, n); netns_fdpair[0] = parse_fd(buf); if (netns_fdpair[0] < 0) return log_debug_errno(netns_fdpair[0], "Unable to parse exec-runtime specification netns-socket-0=%s: %m", buf); if (!fdset_contains(fds, netns_fdpair[0])) return log_debug_errno(SYNTHETIC_ERRNO(EBADF), "exec-runtime specification netns-socket-0= refers to unknown fd %d: %m", netns_fdpair[0]); netns_fdpair[0] = fdset_remove(fds, netns_fdpair[0]); if (v[n] != ' ') goto finalize; p = v + n + 1; } v = startswith(p, "netns-socket-1="); if (v) { char *buf; n = strcspn(v, " "); buf = strndupa_safe(v, n); netns_fdpair[1] = parse_fd(buf); if (netns_fdpair[1] < 0) return log_debug_errno(netns_fdpair[1], "Unable to parse exec-runtime specification netns-socket-1=%s: %m", buf); if (!fdset_contains(fds, netns_fdpair[1])) return log_debug_errno(SYNTHETIC_ERRNO(EBADF), "exec-runtime specification netns-socket-1= refers to unknown fd %d: %m", netns_fdpair[1]); netns_fdpair[1] = fdset_remove(fds, netns_fdpair[1]); if (v[n] != ' ') goto finalize; p = v + n + 1; } v = startswith(p, "ipcns-socket-0="); if (v) { char *buf; n = strcspn(v, " "); buf = strndupa_safe(v, n); ipcns_fdpair[0] = parse_fd(buf); if (ipcns_fdpair[0] < 0) return log_debug_errno(ipcns_fdpair[0], "Unable to parse exec-runtime specification ipcns-socket-0=%s: %m", buf); if (!fdset_contains(fds, ipcns_fdpair[0])) return log_debug_errno(SYNTHETIC_ERRNO(EBADF), "exec-runtime specification ipcns-socket-0= refers to unknown fd %d: %m", ipcns_fdpair[0]); ipcns_fdpair[0] = fdset_remove(fds, ipcns_fdpair[0]); if (v[n] != ' ') goto finalize; p = v + n + 1; } v = startswith(p, "ipcns-socket-1="); if (v) { char *buf; n = strcspn(v, " "); buf = strndupa_safe(v, n); ipcns_fdpair[1] = parse_fd(buf); if (ipcns_fdpair[1] < 0) return log_debug_errno(ipcns_fdpair[1], "Unable to parse exec-runtime specification ipcns-socket-1=%s: %m", buf); if (!fdset_contains(fds, ipcns_fdpair[1])) return log_debug_errno(SYNTHETIC_ERRNO(EBADF), "exec-runtime specification ipcns-socket-1= refers to unknown fd %d: %m", ipcns_fdpair[1]); ipcns_fdpair[1] = fdset_remove(fds, ipcns_fdpair[1]); } finalize: r = exec_shared_runtime_add(m, id, &tmp_dir, &var_tmp_dir, netns_fdpair, ipcns_fdpair, NULL); if (r < 0) return log_debug_errno(r, "Failed to add exec-runtime: %m"); return 0; } void exec_shared_runtime_vacuum(Manager *m) { ExecSharedRuntime *rt; assert(m); /* Free unreferenced ExecSharedRuntime objects. This is used after manager deserialization process. */ HASHMAP_FOREACH(rt, m->exec_shared_runtime_by_id) { if (rt->n_ref > 0) continue; (void) exec_shared_runtime_free(rt); } } int exec_runtime_make(ExecSharedRuntime *shared, DynamicCreds *creds, ExecRuntime **ret) { _cleanup_(exec_runtime_freep) ExecRuntime *rt = NULL; assert(ret); if (!shared && !creds) { *ret = NULL; return 0; } rt = new(ExecRuntime, 1); if (!rt) return -ENOMEM; *rt = (ExecRuntime) { .shared = shared, .dynamic_creds = creds, }; *ret = TAKE_PTR(rt); return 1; } ExecRuntime* exec_runtime_free(ExecRuntime *rt) { if (!rt) return NULL; exec_shared_runtime_unref(rt->shared); dynamic_creds_unref(rt->dynamic_creds); return mfree(rt); } ExecRuntime* exec_runtime_destroy(ExecRuntime *rt) { if (!rt) return NULL; rt->shared = exec_shared_runtime_destroy(rt->shared); rt->dynamic_creds = dynamic_creds_destroy(rt->dynamic_creds); return exec_runtime_free(rt); } void exec_params_clear(ExecParameters *p) { if (!p) return; p->environment = strv_free(p->environment); p->fd_names = strv_free(p->fd_names); p->fds = mfree(p->fds); p->exec_fd = safe_close(p->exec_fd); } ExecSetCredential *exec_set_credential_free(ExecSetCredential *sc) { if (!sc) return NULL; free(sc->id); free(sc->data); return mfree(sc); } ExecLoadCredential *exec_load_credential_free(ExecLoadCredential *lc) { if (!lc) return NULL; free(lc->id); free(lc->path); return mfree(lc); } void exec_directory_done(ExecDirectory *d) { if (!d) return; for (size_t i = 0; i < d->n_items; i++) { free(d->items[i].path); strv_free(d->items[i].symlinks); } d->items = mfree(d->items); d->n_items = 0; d->mode = 0755; } static ExecDirectoryItem *exec_directory_find(ExecDirectory *d, const char *path) { assert(d); assert(path); for (size_t i = 0; i < d->n_items; i++) if (path_equal(d->items[i].path, path)) return &d->items[i]; return NULL; } int exec_directory_add(ExecDirectory *d, const char *path, const char *symlink) { _cleanup_strv_free_ char **s = NULL; _cleanup_free_ char *p = NULL; ExecDirectoryItem *existing; int r; assert(d); assert(path); existing = exec_directory_find(d, path); if (existing) { r = strv_extend(&existing->symlinks, symlink); if (r < 0) return r; return 0; /* existing item is updated */ } p = strdup(path); if (!p) return -ENOMEM; if (symlink) { s = strv_new(symlink); if (!s) return -ENOMEM; } if (!GREEDY_REALLOC(d->items, d->n_items + 1)) return -ENOMEM; d->items[d->n_items++] = (ExecDirectoryItem) { .path = TAKE_PTR(p), .symlinks = TAKE_PTR(s), }; return 1; /* new item is added */ } static int exec_directory_item_compare_func(const ExecDirectoryItem *a, const ExecDirectoryItem *b) { assert(a); assert(b); return path_compare(a->path, b->path); } void exec_directory_sort(ExecDirectory *d) { assert(d); /* Sort the exec directories to make always parent directories processed at first in * setup_exec_directory(), e.g., even if StateDirectory=foo/bar foo, we need to create foo at first, * then foo/bar. Also, set .only_create flag if one of the parent directories is contained in the * list. See also comments in setup_exec_directory() and issue #24783. */ if (d->n_items <= 1) return; typesafe_qsort(d->items, d->n_items, exec_directory_item_compare_func); for (size_t i = 1; i < d->n_items; i++) for (size_t j = 0; j < i; j++) if (path_startswith(d->items[i].path, d->items[j].path)) { d->items[i].only_create = true; break; } } ExecCleanMask exec_clean_mask_from_string(const char *s) { ExecDirectoryType t; assert(s); if (streq(s, "all")) return EXEC_CLEAN_ALL; if (streq(s, "fdstore")) return EXEC_CLEAN_FDSTORE; t = exec_resource_type_from_string(s); if (t < 0) return (ExecCleanMask) t; return 1U << t; } DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(exec_set_credential_hash_ops, char, string_hash_func, string_compare_func, ExecSetCredential, exec_set_credential_free); DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(exec_load_credential_hash_ops, char, string_hash_func, string_compare_func, ExecLoadCredential, exec_load_credential_free); static const char* const exec_input_table[_EXEC_INPUT_MAX] = { [EXEC_INPUT_NULL] = "null", [EXEC_INPUT_TTY] = "tty", [EXEC_INPUT_TTY_FORCE] = "tty-force", [EXEC_INPUT_TTY_FAIL] = "tty-fail", [EXEC_INPUT_SOCKET] = "socket", [EXEC_INPUT_NAMED_FD] = "fd", [EXEC_INPUT_DATA] = "data", [EXEC_INPUT_FILE] = "file", }; DEFINE_STRING_TABLE_LOOKUP(exec_input, ExecInput); static const char* const exec_output_table[_EXEC_OUTPUT_MAX] = { [EXEC_OUTPUT_INHERIT] = "inherit", [EXEC_OUTPUT_NULL] = "null", [EXEC_OUTPUT_TTY] = "tty", [EXEC_OUTPUT_KMSG] = "kmsg", [EXEC_OUTPUT_KMSG_AND_CONSOLE] = "kmsg+console", [EXEC_OUTPUT_JOURNAL] = "journal", [EXEC_OUTPUT_JOURNAL_AND_CONSOLE] = "journal+console", [EXEC_OUTPUT_SOCKET] = "socket", [EXEC_OUTPUT_NAMED_FD] = "fd", [EXEC_OUTPUT_FILE] = "file", [EXEC_OUTPUT_FILE_APPEND] = "append", [EXEC_OUTPUT_FILE_TRUNCATE] = "truncate", }; DEFINE_STRING_TABLE_LOOKUP(exec_output, ExecOutput); static const char* const exec_utmp_mode_table[_EXEC_UTMP_MODE_MAX] = { [EXEC_UTMP_INIT] = "init", [EXEC_UTMP_LOGIN] = "login", [EXEC_UTMP_USER] = "user", }; DEFINE_STRING_TABLE_LOOKUP(exec_utmp_mode, ExecUtmpMode); static const char* const exec_preserve_mode_table[_EXEC_PRESERVE_MODE_MAX] = { [EXEC_PRESERVE_NO] = "no", [EXEC_PRESERVE_YES] = "yes", [EXEC_PRESERVE_RESTART] = "restart", }; DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(exec_preserve_mode, ExecPreserveMode, EXEC_PRESERVE_YES); /* This table maps ExecDirectoryType to the setting it is configured with in the unit */ static const char* const exec_directory_type_table[_EXEC_DIRECTORY_TYPE_MAX] = { [EXEC_DIRECTORY_RUNTIME] = "RuntimeDirectory", [EXEC_DIRECTORY_STATE] = "StateDirectory", [EXEC_DIRECTORY_CACHE] = "CacheDirectory", [EXEC_DIRECTORY_LOGS] = "LogsDirectory", [EXEC_DIRECTORY_CONFIGURATION] = "ConfigurationDirectory", }; DEFINE_STRING_TABLE_LOOKUP(exec_directory_type, ExecDirectoryType); /* This table maps ExecDirectoryType to the symlink setting it is configured with in the unit */ static const char* const exec_directory_type_symlink_table[_EXEC_DIRECTORY_TYPE_MAX] = { [EXEC_DIRECTORY_RUNTIME] = "RuntimeDirectorySymlink", [EXEC_DIRECTORY_STATE] = "StateDirectorySymlink", [EXEC_DIRECTORY_CACHE] = "CacheDirectorySymlink", [EXEC_DIRECTORY_LOGS] = "LogsDirectorySymlink", [EXEC_DIRECTORY_CONFIGURATION] = "ConfigurationDirectorySymlink", }; DEFINE_STRING_TABLE_LOOKUP(exec_directory_type_symlink, ExecDirectoryType); /* And this table maps ExecDirectoryType too, but to a generic term identifying the type of resource. This * one is supposed to be generic enough to be used for unit types that don't use ExecContext and per-unit * directories, specifically .timer units with their timestamp touch file. */ static const char* const exec_resource_type_table[_EXEC_DIRECTORY_TYPE_MAX] = { [EXEC_DIRECTORY_RUNTIME] = "runtime", [EXEC_DIRECTORY_STATE] = "state", [EXEC_DIRECTORY_CACHE] = "cache", [EXEC_DIRECTORY_LOGS] = "logs", [EXEC_DIRECTORY_CONFIGURATION] = "configuration", }; DEFINE_STRING_TABLE_LOOKUP(exec_resource_type, ExecDirectoryType); /* And this table also maps ExecDirectoryType, to the environment variable we pass the selected directory to * the service payload in. */ static const char* const exec_directory_env_name_table[_EXEC_DIRECTORY_TYPE_MAX] = { [EXEC_DIRECTORY_RUNTIME] = "RUNTIME_DIRECTORY", [EXEC_DIRECTORY_STATE] = "STATE_DIRECTORY", [EXEC_DIRECTORY_CACHE] = "CACHE_DIRECTORY", [EXEC_DIRECTORY_LOGS] = "LOGS_DIRECTORY", [EXEC_DIRECTORY_CONFIGURATION] = "CONFIGURATION_DIRECTORY", }; DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(exec_directory_env_name, ExecDirectoryType); static const char* const exec_keyring_mode_table[_EXEC_KEYRING_MODE_MAX] = { [EXEC_KEYRING_INHERIT] = "inherit", [EXEC_KEYRING_PRIVATE] = "private", [EXEC_KEYRING_SHARED] = "shared", }; DEFINE_STRING_TABLE_LOOKUP(exec_keyring_mode, ExecKeyringMode);