upstream commit

Don't call setgroups if we have zero groups; there's no
 guarantee that it won't try to deref the pointer.  Based on a patch from mail
 at quitesimple.org, ok djm deraadt

Upstream-ID: 2fff85e11d7a9a387ef7fddf41fbfaf566708ab1
This commit is contained in:
dtucker@openbsd.org 2015-06-22 12:29:57 +00:00 committed by Damien Miller
parent 5c15e22c69
commit 63b78d003b

View File

@ -1,4 +1,4 @@
/* $OpenBSD: uidswap.c,v 1.37 2015/01/16 06:40:12 deraadt Exp $ */
/* $OpenBSD: uidswap.c,v 1.38 2015/06/22 12:29:57 dtucker Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -113,7 +113,7 @@ temporarily_use_uid(struct passwd *pw)
}
}
/* Set the effective uid to the given (unprivileged) uid. */
if (setgroups(user_groupslen, user_groups) < 0)
if (user_groupslen > 0 && setgroups(user_groupslen, user_groups) < 0)
fatal("setgroups: %.100s", strerror(errno));
#ifndef SAVED_IDS_WORK_WITH_SETEUID
/* Propagate the privileged gid to all of our gids. */
@ -187,7 +187,8 @@ restore_uid(void)
setgid(getgid());
#endif /* SAVED_IDS_WORK_WITH_SETEUID */
if (setgroups(saved_egroupslen, saved_egroups) < 0)
if (saved_egroupslen > 0 &&
setgroups(saved_egroupslen, saved_egroups) < 0)
fatal("setgroups: %.100s", strerror(errno));
temporarily_use_uid_effective = 0;
}