diff options
Diffstat (limited to 'login')
| -rw-r--r-- | login/Makefile | 7 | ||||
| -rw-r--r-- | login/programs/pt_chown.c | 45 |
2 files changed, 44 insertions, 8 deletions
diff --git a/login/Makefile b/login/Makefile index b02d385b66..427c050a89 100644 --- a/login/Makefile +++ b/login/Makefile @@ -1,4 +1,4 @@ -# Copyright (C) 1996-1998,2000-2002,2003,2007 Free Software Foundation, Inc. +# Copyright (C) 1996-1998,2000-2003,2007, 2009 Free Software Foundation, Inc. # This file is part of the GNU C Library. # The GNU C Library is free software; you can redistribute it and/or @@ -54,6 +54,11 @@ otherlibs += $(nssobjdir)/libnss_files.a $(resolvobjdir)/libnss_dns.a \ $(resolvobjdir)/libresolv.a $(common-objpfx)libc.a endif +ifeq (yes,$(have-libcap)) +libcap = -lcap +endif +LDLIBS-pt_chown = $(libcap) + # pt_chown needs to be setuid root. $(inst_libexecdir)/pt_chown: $(objpfx)pt_chown $(+force) $(make-target-directory) diff --git a/login/programs/pt_chown.c b/login/programs/pt_chown.c index 5167b29225..7e279a5f3b 100644 --- a/login/programs/pt_chown.c +++ b/login/programs/pt_chown.c @@ -29,6 +29,10 @@ #include <string.h> #include <sys/stat.h> #include <unistd.h> +#ifdef HAVE_LIBCAP +# include <sys/capability.h> +# include <sys/prctl.h> +#endif #include "pty-private.h" @@ -99,7 +103,7 @@ static int do_pt_chown (void) { char *pty; - struct stat st; + struct stat64 st; struct group *p; gid_t gid; @@ -110,7 +114,7 @@ do_pt_chown (void) /* Check that the returned slave pseudo terminal is a character device. */ - if (stat (pty, &st) < 0 || !S_ISCHR(st.st_mode)) + if (stat64 (pty, &st) < 0 || !S_ISCHR (st.st_mode)) return FAIL_EINVAL; /* Get the group ID of the special `tty' group. */ @@ -136,16 +140,43 @@ int main (int argc, char *argv[]) { uid_t euid = geteuid (); + uid_t uid = getuid (); int remaining; - /* Normal invocation of this program is with no arguments and - with privileges. - FIXME: Should use capable (CAP_CHOWN|CAP_FOWNER). */ if (argc == 1 && euid == 0) - return do_pt_chown (); + { +#ifdef HAVE_LIBCAP + /* Drop privileges. */ + if (uid != euid) + { + static const cap_value_t cap_list[] = + { CAP_CHOWN, CAP_FOWNER }; +# define ncap_list (sizeof (cap_list) / sizeof (cap_list[0])) + cap_t caps = cap_init (); + if (caps == NULL) + error (FAIL_ENOMEM, errno, + _("Failed to initialize drop of capabilities")); + + /* There is no reason why these should not work. */ + cap_set_flag (caps, CAP_PERMITTED, ncap_list, cap_list, CAP_SET); + cap_set_flag (caps, CAP_EFFECTIVE, ncap_list, cap_list, CAP_SET); + + int res = cap_set_proc (caps); + + cap_free (caps); + + if (__builtin_expect (res != 0, 0)) + error (FAIL_EXEC, errno, _("cap_set_proc failed")); + } +#endif + + /* Normal invocation of this program is with no arguments and + with privileges. */ + return do_pt_chown (); + } /* We aren't going to be using privileges, so drop them right now. */ - setuid (getuid ()); + setuid (uid); /* Set locale via LC_ALL. */ setlocale (LC_ALL, ""); |