[Xen-changelog] [qemu-xen-traditional stable-4.6] rtl8139: skip offload on short Ethernet/IP header

[patchbot@xxxxxxx]

commit acbde3d35ffabf03a3154014298ccb9b826ca043
Author:     Stefan Hajnoczi <stefanha@xxxxxxxxxx>
AuthorDate: Wed Jul 15 18:17:00 2015 +0100
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Tue May 10 19:15:12 2016 +0100

    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@xxxxxxxxxx>
    [Backport to qemu-xen-tradition]
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 hw/rtl8139.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/rtl8139.c b/hw/rtl8139.c
index 8b17bd9..75ef9b4 100644
--- a/hw/rtl8139.c
+++ b/hw/rtl8139.c
@@ -2103,6 +2103,11 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s)
             #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;
--
generated by git-patchbot for /home/xen/git/qemu-xen-traditional.git#stable-4.6

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