From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Wed, 15 Jul 2015 17:34:40 +0100
Subject: [PATCH] rtl8139: check IP Total Length field (CVE-2015-5165)
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The IP Total Length field includes the IP header and data.  Make sure it
is valid and does not exceed the Ethernet payload size.

Reported-by: 朱东海(启路) <donghai.zdh@alibaba-inc.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit c6296ea88df040054ccd781f3945fe103f8c7c17)
---
 hw/net/rtl8139.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index 14082cb..207c2e4 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -2201,7 +2201,12 @@ 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)
             {