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If we are unable to stat() sudoers as non-root, try again as root.

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By default, sudo relies soley on group permissions to read sudoers
to make it possible to store sudoers on NFS.  However, if /etc/sudoers
is not accessible to non-root uids for some reason, sudo will fail.
Bug #880.
This commit is contained in:
Todd C. Miller
2019-07-14 18:51:50 -06:00
parent 10b5529a0b
commit cecf69ff3c
1 changed files with 23 additions and 0 deletions
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23
plugins/sudoers/sudoers.c
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@@ -879,11 +879,20 @@ open_sudoers(const char *sudoers, bool doedit, bool *keepopen)
{
struct stat sb;
FILE *fp = NULL;
bool asroot = true;
debug_decl(open_sudoers, SUDOERS_DEBUG_PLUGIN)
if (!set_perms(PERM_SUDOERS))
debug_return_ptr(NULL);
/*
* If sudoers_uid == ROOT_UID and sudoers_mode is group readable
* set_perms() will use a non-zero uid in order to avoid NFS issues..
*/
if (sudoers_uid != ROOT_UID || ISSET(sudoers_mode, S_IRGRP))
asroot = false;
again:
switch (sudo_secure_file(sudoers, sudoers_uid, sudoers_gid, &sb)) {
case SUDO_PATH_SECURE:
/*
@@ -917,6 +926,20 @@ open_sudoers(const char *sudoers, bool doedit, bool *keepopen)
}
break;
case SUDO_PATH_MISSING:
/*
* If we tried to stat() sudoers as non-root but got EACCES,
* try again as root.
*/
if (errno == EACCES && !asroot) {
int serrno = errno;
if (restore_perms()) {
if (!set_perms(PERM_ROOT))
debug_return_ptr(NULL);
asroot = true;
goto again;
}
errno = serrno;
}
log_warning(SLOG_SEND_MAIL, N_("unable to stat %s"), sudoers);
break;
case SUDO_PATH_BAD_TYPE: