References: bsc#939712 XSA-140
From 043d28507ef7c5fdc34866f5e3b27a72bd0cd072 Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Wed, 15 Jul 2015 18:17:00 +0100
Subject: [PATCH 3/7] rtl8139: skip offload on short Ethernet/IP header
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>
---
hw/rtl8139.c | 5 +++++
1 file changed, 5 insertions(+)
Index: xen-4.5.1-testing/tools/qemu-xen-traditional-dir-remote/hw/rtl8139.c
===================================================================
--- xen-4.5.1-testing.orig/tools/qemu-xen-traditional-dir-remote/hw/rtl8139.c
+++ xen-4.5.1-testing/tools/qemu-xen-traditional-dir-remote/hw/rtl8139.c
@@ -2103,6 +2103,11 @@ static int rtl8139_cplus_transmit_one(RT
#define ETH_HLEN 14
#define ETH_MTU 1500
+ /* Large enough for Ethernet and IP headers? */
+ if (saved_size < ETH_HLEN + sizeof(ip_header)) {
+ goto skip_offload;
+ }
+
/* ip packet header */
ip_header *ip = 0;
int hlen = 0;