From: Serge Hallyn <shallyn@cisco.com>
Date: Wed, 9 May 2018 02:37:55 +0000 (-0500)
Subject: usermod: prevent a segv
X-Git-Tag: 4.7~36
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=48dcf7852e51b9d8e7926737cc7f7823978b7d7d;p=shadow

usermod: prevent a segv

in the case where prefix does not exist.

Signed-off-by: Serge Hallyn <shallyn@cisco.com>
---

diff --git a/libmisc/prefix_flag.c b/libmisc/prefix_flag.c
index 8ceffd26..96b11faa 100644
--- a/libmisc/prefix_flag.c
+++ b/libmisc/prefix_flag.c
@@ -319,6 +319,7 @@ extern struct group *prefix_getgr_nam_gid(const char *grname)
 {
 	long long int gid;
 	char *endptr;
+	struct group *g;
 
 	if (NULL == grname) {
 		return NULL;
@@ -333,7 +334,8 @@ extern struct group *prefix_getgr_nam_gid(const char *grname)
 	    	&& (gid == (gid_t)gid)) {
 			return prefix_getgrgid ((gid_t) gid);
 		}
-		return __gr_dup(prefix_getgrnam (grname));
+		g = prefix_getgrnam (grname);
+		return g ? __gr_dup(g) : NULL;
 	}
 	else
 		return getgr_nam_gid(grname);