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From 00e16a0908803bf1e796864511862067a763e95e Mon Sep 17 00:00:00 2001
From: Miroslav Rezanina <mrezanin@redhat.com>
Date: Thu, 23 Oct 2014 09:19:24 +0200
Subject: [PATCH 1/9] slirp: udp: fix NULL pointer dereference because of
 uninitialized socket

Message-id: <1414055964-27479-1-git-send-email-mrezanin@redhat.com>
Patchwork-id: 61832
O-Subject: [RHEL-7.1 qemu-kvm PATCH] slirp: udp: fix NULL pointer dereference because of uninitialized socket
Bugzilla: 1144820
RH-Acked-by: Petr Matousek <pmatouse@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Amos Kong <akong@redhat.com>

From: Petr Matousek <pmatouse@redhat.com>

When guest sends udp packet with source port and source addr 0,
uninitialized socket is picked up when looking for matching and already
created udp sockets, and later passed to sosendto() where NULL pointer
dereference is hit during so->slirp->vnetwork_mask.s_addr access.

Fix this by checking that the socket is not just a socket stub.

This is CVE-2014-3640.

Signed-off-by: Petr Matousek <pmatouse@redhat.com>
Reported-by: Xavier Mehrenberger <xavier.mehrenberger@airbus.com>
Reported-by: Stephane Duverger <stephane.duverger@eads.net>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Message-id: 20140918063537.GX9321@dhcp-25-225.brq.redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit 01f7cecf0037997cb0e58ec0d56bf9b5a6f7cb2a)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 slirp/udp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/slirp/udp.c b/slirp/udp.c
index b105f87..2188176 100644
--- a/slirp/udp.c
+++ b/slirp/udp.c
@@ -152,7 +152,7 @@ udp_input(register struct mbuf *m, int iphlen)
 	 * Locate pcb for datagram.
 	 */
 	so = slirp->udp_last_so;
-	if (so->so_lport != uh->uh_sport ||
+	if (so == &slirp->udb || so->so_lport != uh->uh_sport ||
 	    so->so_laddr.s_addr != ip->ip_src.s_addr) {
 		struct socket *tmp;
 
-- 
1.8.3.1