diff -up shadow-4.1.2/src/groupmems.c.gmSEGV shadow-4.1.2/src/groupmems.c
--- shadow-4.1.2/src/groupmems.c.gmSEGV	2008-04-22 22:05:11.000000000 +0200
+++ shadow-4.1.2/src/groupmems.c	2008-09-02 08:30:52.000000000 +0200
@@ -95,7 +95,7 @@ static char *whoami (void)
 	}
 }
 
-static void addtogroup (char *user, char **members)
+static char **addtogroup (char *user, char **members)
 {
 	int i;
 
@@ -109,6 +109,8 @@ static void addtogroup (char *user, char
 	members = (char **) realloc (members, sizeof (char *) * (i+2));
 	members[i] = user;
 	members[i + 1] = NULL;
+
+	return members;
 }
 
 static void rmfromgroup (char *user, char **members)
@@ -285,7 +287,7 @@ int main (int argc, char **argv) 
 	grp = (struct group *) gr_locate (name);
 
 	if (NULL != adduser) {
-		addtogroup (adduser, grp->gr_mem);
+		grp->gr_mem = addtogroup (adduser, grp->gr_mem);
 		gr_update (grp);
 	} else if (NULL != deluser) {
 		rmfromgroup (deluser, grp->gr_mem);