===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/uidswap.c,v
retrieving revision 1.37
retrieving revision 1.38
diff -u -r1.37 -r1.38
--- src/usr.bin/ssh/uidswap.c	2015/01/16 06:40:12	1.37
+++ src/usr.bin/ssh/uidswap.c	2015/06/22 12:29:57	1.38
@@ -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
@@ -76,7 +76,7 @@
 			fatal("getgroups: %.100s", strerror(errno));
 	}
 	/* 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));
 	if (setegid(pw->pw_gid) < 0)
 		fatal("setegid %u: %.100s", (u_int)pw->pw_gid,
@@ -103,7 +103,8 @@
 	/* Set the effective uid back to the saved privileged uid. */
 	if (seteuid(saved_euid) < 0)
 		fatal("seteuid %u: %.100s", (u_int)saved_euid, strerror(errno));
-	if (setgroups(saved_egroupslen, saved_egroups) < 0)
+	if (saved_egroupslen > 0 &&
+	    setgroups(saved_egroupslen, saved_egroups) < 0)
 		fatal("setgroups: %.100s", strerror(errno));
 	if (setegid(saved_egid) < 0)
 		fatal("setegid %u: %.100s", (u_int)saved_egid, strerror(errno));