From 13c28d943d8c8501a1e0dc8a3e11423b9ca9116f Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Thu, 30 Jul 2015 14:34:54 +0200
Subject: [PATCH 7/7] rtl8139: check TCP Data Offset field (CVE-2015-5165)
Message-id: <1438266894-23344-8-git-send-email-stefanha@redhat.com>
Patchwork-id: 67228
O-Subject: [virt-devel] [RHEV-7.1.z qemu-kvm-rhev EMBARGOED PATCH 7/7] rtl8139: check TCP Data Offset field (CVE-2015-5165)
Bugzilla: 1248768
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Xiao Wang <jasowang@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The TCP Data Offset field contains the length of the header. Make sure
it is valid and does not exceed the IP data length.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
hw/net/rtl8139.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index 99d8f4a..e738812 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -2239,6 +2239,11 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s)
int tcp_hlen = TCP_HEADER_DATA_OFFSET(p_tcp_hdr);
+ /* Invalid TCP data offset? */
+ if (tcp_hlen < sizeof(tcp_header) || tcp_hlen > ip_data_len) {
+ goto skip_offload;
+ }
+
/* ETH_MTU = ip header len + tcp header len + payload */
int tcp_data_len = ip_data_len - tcp_hlen;
int tcp_chunk_size = ETH_MTU - hlen - tcp_hlen;
--
1.8.3.1