Dapper CVE-2010-3873, memory corruption in X.25 facilities parsing

[Tim Gardner]

The following changes since commit 9f646039dcba8632e8d68f73652ce6949d6b20ba:
  David S. Miller (1):
        net: Limit socket I/O iovec total length to INT_MAX., CVE-2010-3859

are available in the git repository at:

  git://kernel.ubuntu.com/rtg/ubuntu-dapper.git CVE-2010-3873

Tim Gardner (1):
      memory corruption in X.25 facilities parsing, CVE-2010-3873

 net/x25/x25_in.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

>From 92700cf43dcb6ffdd998550a2ecadb7a2343e222 Mon Sep 17 00:00:00 2001
From: Tim Gardner <tim.gardner at canonical.com>
Date: Fri, 28 Jan 2011 11:17:01 -0700
Subject: [PATCH] memory corruption in X.25 facilities parsing, CVE-2010-3873

BugLink: http://bugs.launchpad.net/bugs/709372

CVE-2010-3873

Partial backport from a6331d6f9a4298173b413cf99a40cc86a9d92c37
by Tim Gardner <tim.gardner at canonical.com>

Signed-of-by: Andrew Hendry <andrew.hendry at gmail.com>

Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 net/x25/x25_in.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/x25/x25_in.c b/net/x25/x25_in.c
index 2614687..659252b 100644
--- a/net/x25/x25_in.c
+++ b/net/x25/x25_in.c
@@ -90,6 +90,7 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp
 	switch (frametype) {
 		case X25_CALL_ACCEPTED: {
 			struct x25_sock *x25 = x25_sk(sk);
+			int len;
 
 			x25_stop_timer(sk);
 			x25->condition = 0x00;
@@ -104,9 +105,12 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp
 			 */
 			skb_pull(skb, X25_STD_MIN_LEN);
 			skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
-			skb_pull(skb,
-				 x25_parse_facilities(skb, &x25->facilities,
-						      &x25->vc_facil_mask));
+			len = x25_parse_facilities(skb, &x25->facilities,
+							&x25->vc_facil_mask);
+			if (len <= 0)
+				return -1;
+			skb_pull(skb, len);
+
 			/*
 			 *	Copy any Call User Data.
 			 */
-- 
1.7.0.4