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

[Tim Gardner]

The following changes since commit 726f4409a25c6c39b57efcb52375c9c5490c809d:
  Linus Torvalds (1):
        net: Truncate recvfrom and sendto length to INT_MAX., CVE-2010-3859

are available in the git repository at:

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

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

 net/x25/x25_facilities.c |    8 ++++----
 net/x25/x25_in.c         |   11 +++++++----
 2 files changed, 11 insertions(+), 8 deletions(-)

>From 5f702dc29cadc092040622d1a653d74557da1834 Mon Sep 17 00:00:00 2001
From: andrew hendry <andrew.hendry at gmail.com>
Date: Wed, 3 Nov 2010 12:54:53 +0000
Subject: [PATCH] memory corruption in X.25 facilities parsing, CVE-2010-3873

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

CVE-2010-3873

Backported 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_facilities.c |    8 ++++----
 net/x25/x25_in.c         |   11 +++++++----
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c
index dec404a..fa5eb98 100644
--- a/net/x25/x25_facilities.c
+++ b/net/x25/x25_facilities.c
@@ -126,15 +126,15 @@ int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities,
 		case X25_FAC_CLASS_D:
 			switch (*p) {
 			case X25_FAC_CALLING_AE:
-				if (p[1] > X25_MAX_DTE_FACIL_LEN)
-					break;
+				if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
+					return 0;
 				dte_facs->calling_len = p[2];
 				memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
 				*vc_fac_mask |= X25_MASK_CALLING_AE;
 				break;
 			case X25_FAC_CALLED_AE:
-				if (p[1] > X25_MAX_DTE_FACIL_LEN)
-					break;
+				if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
+					return 0;
 				dte_facs->called_len = p[2];
 				memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
 				*vc_fac_mask |= X25_MASK_CALLED_AE;
diff --git a/net/x25/x25_in.c b/net/x25/x25_in.c
index 1c88762..4cae6cb 100644
--- a/net/x25/x25_in.c
+++ b/net/x25/x25_in.c
@@ -93,6 +93,7 @@ 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;
@@ -107,10 +108,12 @@ 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->dte_facilities,
-						&x25->vc_facil_mask));
+			len = x25_parse_facilities(skb, &x25->facilities,
+				&x25->dte_facilities, &x25->vc_facil_mask);
+			if (len <= 0)
+				return -1;
+			skb_pull(skb, len);
+
 			/*
 			 *	Copy any Call User Data.
 			 */
-- 
1.7.0.4