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policycoreutils: seunshare: do checking on setfsuid

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setfsuid return codes were not being checked.  Add checks to make sure
we are switching from and to what we expect.  Bail (most places) if we
didn't switch successfully.

Signed-off-by: Eric Paris <eparis@redhat.com>
This commit is contained in:
Eric Paris 2012-09-26 11:00:56 -04:00
parent 92788715dc
commit 221e6d4665
1 changed files with 27 additions and 14 deletions
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41
policycoreutils/sandbox/seunshare.c
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@ -617,12 +617,19 @@ static int cleanup_tmpdir(const char *tmpdir, const char *src,
free(cmdbuf); cmdbuf = NULL;
/* remove runtime temporary directory */
setfsuid(0);
if ((uid_t)setfsuid(0) != pwd->pw_uid) {
fprintf(stderr, _("Unable to switch to root to clear tmp dir\n"));
rc++;
}
if (rmdir(tmpdir) == -1)
fprintf(stderr, _("Failed to remove directory %s: %s\n"), tmpdir, strerror(errno));
setfsuid(pwd->pw_uid);
if ((uid_t)setfsuid(pwd->pw_uid) != 0) {
fprintf(stderr, _("unable to switch back to user after clearing tmp dir\n"));
rc++;
}
return 0;
return rc;
}
/**
@ -642,7 +649,9 @@ static char *create_tmpdir(const char *src, struct stat *src_st,
/* get selinux context */
if (execcon) {
setfsuid(pwd->pw_uid);
if ((uid_t)setfsuid(pwd->pw_uid) != 0)
goto err;
if ((fd_s = open(src, O_RDONLY)) < 0) {
fprintf(stderr, _("Failed to open directory %s: %s\n"), src, strerror(errno));
goto err;
@ -661,7 +670,8 @@ static char *create_tmpdir(const char *src, struct stat *src_st,
}
/* ok to not reach this if there is an error */
setfsuid(0);
if ((uid_t)setfsuid(0) != pwd->pw_uid)
goto err;
}
if (asprintf(&tmpdir, "/tmp/.sandbox-%s-XXXXXX", pwd->pw_name) == -1) {
@ -716,14 +726,16 @@ static char *create_tmpdir(const char *src, struct stat *src_st,
}
}
setfsuid(pwd->pw_uid);
if ((uid_t)setfsuid(pwd->pw_uid) != 0)
goto err;
if (rsynccmd(src, tmpdir, &cmdbuf) < 0) {
goto err;
}
/* ok to not reach this if there is an error */
setfsuid(0);
if ((uid_t)setfsuid(0) != pwd->pw_uid)
goto err;
if (cmdbuf && spawn_command(cmdbuf, pwd->pw_uid) != 0) {
fprintf(stderr, _("Failed to populate runtime temporary directory\n"));
@ -919,7 +931,8 @@ int main(int argc, char **argv) {
/* Changing fsuid is usually required when user-specified directory is
* on an NFS mount. It's also desired to avoid leaking info about
* existence of the files not accessible to the user. */
setfsuid(uid);
if ((uid_t)setfsuid(uid) != 0)
return -1;
/* verify homedir and tmpdir */
if (homedir_s && (
@ -928,7 +941,7 @@ int main(int argc, char **argv) {
if (tmpdir_s && (
verify_directory(tmpdir_s, NULL, &st_tmpdir_s) < 0 ||
check_owner_uid(uid, tmpdir_s, &st_tmpdir_s))) return -1;
setfsuid(0);
if ((uid_t)setfsuid(0) != uid) return -1;
/* create runtime tmpdir */
if (tmpdir_s && (tmpdir_r = create_tmpdir(tmpdir_s, &st_tmpdir_s,
@ -962,7 +975,7 @@ int main(int argc, char **argv) {
}
/* assume fsuid==ruid after this point */
setfsuid(uid);
if ((uid_t)setfsuid(uid) != 0) goto childerr;
/* mount homedir and tmpdir, in this order */
if (homedir_s && seunshare_mount(homedir_s, pwd->pw_dir,
@ -979,7 +992,7 @@ int main(int argc, char **argv) {
goto childerr;
}
}
/* construct a new environment */
if ((LANG = getenv("LANG")) != NULL) {
if ((LANG = strdup(LANG)) == NULL) {
@ -987,14 +1000,14 @@ int main(int argc, char **argv) {
goto childerr;
}
}
if ((rc = clearenv()) != 0) {
perror(_("Failed to clear environment"));
goto childerr;
}
if (display)
rc |= setenv("DISPLAY", display, 1);
if (LANG)
if (LANG)
rc |= setenv("LANG", LANG, 1);
rc |= setenv("HOME", pwd->pw_dir, 1);
rc |= setenv("SHELL", pwd->pw_shell, 1);
@ -1008,7 +1021,7 @@ int main(int argc, char **argv) {
/* selinux context */
if (execcon && setexeccon(execcon) != 0) {
fprintf(stderr, _("Could not set exec context to %s.\n"), execcon);
fprintf(stderr, _("Could not set exec context to %s. %s\n"), execcon, strerror(errno));
goto childerr;
}