[Xen-changelog] [qemu-xen-traditional stable-4.4] rtl8139: skip offload on short TCP header

[patchbot@xxxxxxx]

commit 5cb90b247edc3e77f17c6a52c3830de48e0d5975
Author:     Stefan Hajnoczi <stefanha@xxxxxxxxxx>
AuthorDate: Wed Jul 15 18:17:03 2015 +0100
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Tue May 10 19:16:20 2016 +0100

    rtl8139: skip offload on short TCP header
    
    TCP Large Segment Offload accesses the TCP header in the packet.  If the
    packet is too short we must not attempt to access header fields:
    
      tcp_header *p_tcp_hdr = (tcp_header*)(eth_payload_data + hlen);
      int tcp_hlen = TCP_HEADER_DATA_OFFSET(p_tcp_hdr);
    
    Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
    [Backport to qemu-xen-tradition]
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 hw/rtl8139.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/rtl8139.c b/hw/rtl8139.c
index d49d6fa..0bb4583 100644
--- a/hw/rtl8139.c
+++ b/hw/rtl8139.c
@@ -2163,9 +2163,15 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s)
 
             if ((txdw0 & CP_TX_LGSEN) && ip_protocol == IP_PROTO_TCP)
             {
+
 #if defined (DEBUG_RTL8139)
                 int large_send_mss = (txdw0 >> 16) & CP_TC_LGSEN_MSS_MASK;
 #endif
+                /* Large enough for the TCP header? */
+                if (ip_data_len < sizeof(tcp_header)) {
+                    goto skip_offload;
+                }
+
                 DEBUG_PRINT(("RTL8139: +++ C+ mode offloaded task TSO MTU=%d 
IP data %d frame data %d specified MSS=%d\n",
                              ETH_MTU, ip_data_len, saved_size - ETH_HLEN, 
large_send_mss));
 
--
generated by git-patchbot for /home/xen/git/qemu-xen-traditional.git#stable-4.4

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