[Qemu-stable] [PULL for-2.4 5/7] rtl8139: check IP Total Length field (CVE-2015-5165)

[Stefan Hajnoczi]

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) <address@hidden>
Reviewed-by: Jason Wang <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
 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 4eaa352..6859d76 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -2191,7 +2191,12 @@ 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)
             {
-- 
2.4.3