http://bugs.gentoo.org/300790
http://lists.alioth.debian.org/pipermail/pkg-shadow-devel/2009-November/007850.html

2009-11-05  Nicolas François  <nicolas.francois@centraliens.net>

	* NEWS, src/groupmod.c: Fixed groupmod when configured with
	--enable-account-tools-setuid.

Index: shadow-4.1.4.2/src/groupmod.c
===================================================================
--- shadow-4.1.4.2.orig/src/groupmod.c	2009-06-05 15:16:58.000000000 -0700
+++ shadow-4.1.4.2/src/groupmod.c	2010-06-03 17:45:43.828952613 -0700
@@ -720,7 +720,7 @@ int main (int argc, char **argv)
 	{
 		struct passwd *pampw;
 		pampw = getpwuid (getuid ()); /* local, no need for xgetpwuid */
-		if (NULL == pamh) {
+		if (NULL == pampw) {
 			fprintf (stderr,
 			         _("%s: Cannot determine your user name.\n"),
 			         Prog);