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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <sched.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <unistd.h>
#include "btrfs-util.h"
#include "capability-util.h"
#include "fd-util.h"
#include "import-common.h"
#include "process-util.h"
#include "signal-util.h"
#include "util.h"
int import_make_read_only_fd(int fd) {
int r;
assert(fd >= 0);
/* First, let's make this a read-only subvolume if it refers
* to a subvolume */
r = btrfs_subvol_set_read_only_fd(fd, true);
if (IN_SET(r, -ENOTTY, -ENOTDIR, -EINVAL)) {
struct stat st;
/* This doesn't refer to a subvolume, or the file
* system isn't even btrfs. In that, case fall back to
* chmod()ing */
r = fstat(fd, &st);
if (r < 0)
return log_error_errno(errno, "Failed to stat temporary image: %m");
/* Drop "w" flag */
if (fchmod(fd, st.st_mode & 07555) < 0)
return log_error_errno(errno, "Failed to chmod() final image: %m");
return 0;
} else if (r < 0)
return log_error_errno(r, "Failed to make subvolume read-only: %m");
return 0;
}
int import_make_read_only(const char *path) {
_cleanup_close_ int fd = 1;
fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return log_error_errno(errno, "Failed to open %s: %m", path);
return import_make_read_only_fd(fd);
}
int import_fork_tar_x(const char *path, pid_t *ret) {
_cleanup_close_pair_ int pipefd[2] = { -1, -1 };
pid_t pid;
int r;
assert(path);
assert(ret);
if (pipe2(pipefd, O_CLOEXEC) < 0)
return log_error_errno(errno, "Failed to create pipe for tar: %m");
r = safe_fork("(tar)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
if (r < 0)
return r;
if (r == 0) {
uint64_t retain =
(1ULL << CAP_CHOWN) |
(1ULL << CAP_FOWNER) |
(1ULL << CAP_FSETID) |
(1ULL << CAP_MKNOD) |
(1ULL << CAP_SETFCAP) |
(1ULL << CAP_DAC_OVERRIDE);
/* Child */
pipefd[1] = safe_close(pipefd[1]);
r = rearrange_stdio(pipefd[0], -1, STDERR_FILENO);
if (r < 0) {
log_error_errno(r, "Failed to rearrange stdin/stdout: %m");
_exit(EXIT_FAILURE);
}
if (unshare(CLONE_NEWNET) < 0)
log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m");
r = capability_bounding_set_drop(retain, true);
if (r < 0)
log_error_errno(r, "Failed to drop capabilities, ignoring: %m");
execlp("tar", "tar", "--numeric-owner", "-C", path, "-px", "--xattrs", "--xattrs-include=*", NULL);
log_error_errno(errno, "Failed to execute tar: %m");
_exit(EXIT_FAILURE);
}
*ret = pid;
return TAKE_FD(pipefd[1]);
}
int import_fork_tar_c(const char *path, pid_t *ret) {
_cleanup_close_pair_ int pipefd[2] = { -1, -1 };
pid_t pid;
int r;
assert(path);
assert(ret);
if (pipe2(pipefd, O_CLOEXEC) < 0)
return log_error_errno(errno, "Failed to create pipe for tar: %m");
r = safe_fork("(tar)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
if (r < 0)
return r;
if (r == 0) {
uint64_t retain = (1ULL << CAP_DAC_OVERRIDE);
/* Child */
pipefd[0] = safe_close(pipefd[0]);
r = rearrange_stdio(-1, pipefd[1], STDERR_FILENO);
if (r < 0) {
log_error_errno(r, "Failed to rearrange stdin/stdout: %m");
_exit(EXIT_FAILURE);
}
if (unshare(CLONE_NEWNET) < 0)
log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m");
r = capability_bounding_set_drop(retain, true);
if (r < 0)
log_error_errno(r, "Failed to drop capabilities, ignoring: %m");
execlp("tar", "tar", "-C", path, "-c", "--xattrs", "--xattrs-include=*", ".", NULL);
log_error_errno(errno, "Failed to execute tar: %m");
_exit(EXIT_FAILURE);
}
*ret = pid;
return TAKE_FD(pipefd[0]);
}
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