Fix CVE-2012-6085 by backporting a patch from upstream's git repository.

Upstream-Status: Backport
Signed-off-by: Ross Burton <ross.burton@intel.com>


From 498882296ffac7987c644aaf2a0aa108a2925471 Mon Sep 17 00:00:00 2001
From: Werner Koch <wk@gnupg.org>
Date: Thu, 20 Dec 2012 09:43:41 +0100
Subject: [PATCH] gpg: Import only packets which are allowed in a keyblock.

* g10/import.c (valid_keyblock_packet): New.
(read_block): Store only valid packets.
--

A corrupted key, which for example included a mangled public key
encrypted packet, used to corrupt the keyring.  This change skips all
packets which are not allowed in a keyblock.

GnuPG-bug-id: 1455

(cherry-picked from commit 3a4b96e665fa639772854058737ee3d54ba0694e)
---
 g10/import.c |   23 ++++++++++++++++++++++-
 1 files changed, 22 insertions(+), 1 deletions(-)

diff --git a/g10/import.c b/g10/import.c
index ba2439d..ad112d6 100644
--- a/g10/import.c
+++ b/g10/import.c
@@ -347,6 +347,27 @@ import_print_stats (void *hd)
 }
 
 
+/* Return true if PKTTYPE is valid in a keyblock.  */
+static int
+valid_keyblock_packet (int pkttype)
+{
+  switch (pkttype)
+    {
+    case PKT_PUBLIC_KEY:
+    case PKT_PUBLIC_SUBKEY:
+    case PKT_SECRET_KEY:
+    case PKT_SECRET_SUBKEY:
+    case PKT_SIGNATURE:
+    case PKT_USER_ID:
+    case PKT_ATTRIBUTE:
+    case PKT_RING_TRUST:
+      return 1;
+    default:
+      return 0;
+    }
+}
+
+
 /****************
  * Read the next keyblock from stream A.
  * PENDING_PKT should be initialzed to NULL
@@ -424,7 +445,7 @@ read_block( IOBUF a, PACKET **pending_pkt, KBNODE *ret_root )
 	    }
 	    in_cert = 1;
 	  default:
-	    if( in_cert ) {
+	    if (in_cert && valid_keyblock_packet (pkt->pkttype)) {
 		if( !root )
 		    root = new_kbnode( pkt );
 		else
-- 
1.7.2.5

