From 8d1eb5c74413e4c9a21f689fc106949b121c0117 Mon Sep 17 00:00:00 2001
From: mancha <mancha1@hush.com>
Date: Wed, 22 May 2013 14:20:26 +0000
Subject: Handle NULL returns from glibc 2.17+ crypt().

Starting with glibc 2.17 (eglibc 2.17), crypt() fails with EINVAL
(w/ NULL return) if the salt violates specifications. Additionally,
on FIPS-140 enabled Linux systems, DES/MD5-encrypted passwords
passed to crypt() fail with EPERM (w/ NULL return).

If using glibc's crypt(), check return value to avoid a possible
NULL pointer dereference.

Reviewed-by: Matthieu Herrb <matthieu@herrb.eu>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
---
diff --git a/greeter/verify.c b/greeter/verify.c
index db3cb7d..b009e2b 100644
--- a/greeter/verify.c
+++ b/greeter/verify.c
@@ -329,6 +329,7 @@ Verify (struct display *d, struct greet_info *greet, struct verify_info *verify)
 	struct spwd	*sp;
 #  endif
 	char		*user_pass = NULL;
+	char		*crypted_pass = NULL;
 # endif
 # ifdef __OpenBSD__
 	char            *s;
@@ -464,7 +465,9 @@ Verify (struct display *d, struct greet_info *greet, struct verify_info *verify)
 #  if defined(ultrix) || defined(__ultrix__)
 	if (authenticate_user(p, greet->password, NULL) < 0)
 #  else
-	if (strcmp (crypt (greet->password, user_pass), user_pass))
+	crypted_pass = crypt (greet->password, user_pass);
+	if ((crypted_pass == NULL)
+	    || (strcmp (crypted_pass, user_pass)))
 #  endif
 	{
 		if(!greet->allow_null_passwd || strlen(p->pw_passwd) > 0) {
--
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