From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Wed, 15 Jul 2015 17:17:02 +0000 (+0100)
Subject: rtl8139: check IP Total Length field
X-Git-Tag: qemu-xen-4.6.0-rc1~3
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=b649863740fb3b93ba716d665fbfa1ce83cb5936;p=qemu-upstream-unstable.git

rtl8139: check IP Total Length field

The IP Total Length field includes the IP header and data.  Make sure it
is valid and does not exceed the Ethernet payload size.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---

diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index cd5ac0581..ed2b23b90 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -2205,7 +2205,12 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s)
             }
 
             ip_protocol = ip->ip_p;
-            ip_data_len = be16_to_cpu(ip->ip_len) - hlen;
+
+            ip_data_len = be16_to_cpu(ip->ip_len);
+            if (ip_data_len < hlen || ip_data_len > eth_payload_len) {
+                goto skip_offload;
+            }
+            ip_data_len -= hlen;
 
             if (txdw0 & CP_TX_IPCS)
             {