From df97cf05d6dc1a48493c5452c96a261dbc233750 Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Thu, 30 Jul 2015 14:34:50 +0200
Subject: [PATCH 3/7] rtl8139: skip offload on short Ethernet/IP header
(CVE-2015-5165)
Message-id: <1438266894-23344-4-git-send-email-stefanha@redhat.com>
Patchwork-id: 67224
O-Subject: [virt-devel] [RHEV-7.1.z qemu-kvm-rhev EMBARGOED PATCH 3/7] rtl8139: skip offload on short Ethernet/IP header (CVE-2015-5165)
Bugzilla: 1248768
RH-Acked-by: Xiao Wang <jasowang@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Transmit offload features access Ethernet and IP headers the packet. If
the packet is too short we must not attempt to access header fields:
int proto = be16_to_cpu(*(uint16_t *)(saved_buffer + 12));
...
eth_payload_data = saved_buffer + ETH_HLEN;
...
ip = (ip_header*)eth_payload_data;
if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {
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 cc6791a..1f04190 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -2150,6 +2150,11 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s)
{
DPRINTF("+++ C+ mode offloaded task checksum\n");
+ /* Large enough for Ethernet and IP headers? */
+ if (saved_size < ETH_HLEN + sizeof(ip_header)) {
+ goto skip_offload;
+ }
+
/* ip packet header */
ip_header *ip = NULL;
int hlen = 0;
--
1.8.3.1