[Xen-changelog] [qemu-xen stable-4.6] pcnet: fix rx buffer overflow(CVE-2015-7512)

[patchbot@xxxxxxx]

commit 75c57190671cd2cfdfbbc448fb3c752dc46018d8
Author:     Jason Wang <jasowang@xxxxxxxxxx>
AuthorDate: Mon Nov 30 15:00:06 2015 +0800
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
CommitDate: Fri Feb 5 13:58:51 2016 +0000

    pcnet: fix rx buffer overflow(CVE-2015-7512)
    
    Backends could provide a packet whose length is greater than buffer
    size. Check for this and truncate the packet to avoid rx buffer
    overflow in this case.
    
    Cc: Prasad J Pandit <pjp@xxxxxxxxxxxxxxxxx>
    Cc: qemu-stable@xxxxxxxxxx
    Reviewed-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
 hw/net/pcnet.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/net/pcnet.c b/hw/net/pcnet.c
index f510932..9f0ab41 100644
--- a/hw/net/pcnet.c
+++ b/hw/net/pcnet.c
@@ -1086,6 +1086,12 @@ ssize_t pcnet_receive(NetClientState *nc, const uint8_t 
*buf, size_t size_)
             int pktcount = 0;
 
             if (!s->looptest) {
+                if (size > 4092) {
+#ifdef PCNET_DEBUG_RMD
+                    fprintf(stderr, "pcnet: truncates rx packet.\n");
+#endif
+                    size = 4092;
+                }
                 memcpy(src, buf, size);
                 /* no need to compute the CRC */
                 src[size] = 0;
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#stable-4.6

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