[Xen-changelog] [qemu-upstream-unstable] e1000: Avoid infinite loop in processing transmit descriptor (CVE-2015-6815)

[patchbot@xxxxxxx]

commit 00d751038d501ab40298ebe972addfcf4ea0c54b
Author:     P J P <pjp@xxxxxxxxxxxxxxxxx>
AuthorDate: Fri Sep 4 17:21:06 2015 +0100
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
CommitDate: Tue Sep 15 13:42:54 2015 +0000

    e1000: Avoid infinite loop in processing transmit descriptor (CVE-2015-6815)
    
    While processing transmit descriptors, it could lead to an infinite
    loop if 'bytes' was to become zero; Add a check to avoid it.
    
    [The guest can force 'bytes' to 0 by setting the hdr_len and mss
    descriptor fields to 0.
    --Stefan]
    
    upstream-commit-id: b947ac2bf26479e710489739c465c8af336599e7
    
    Signed-off-by: P J P <pjp@xxxxxxxxxxxxxxxxx>
    Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
    Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx>
    Message-id: 1441383666-6590-1-git-send-email-stefanha@xxxxxxxxxx
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 hw/net/e1000.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/hw/net/e1000.c b/hw/net/e1000.c
index e33a4da..3032855 100644
--- a/hw/net/e1000.c
+++ b/hw/net/e1000.c
@@ -736,7 +736,8 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
                 memmove(tp->data, tp->header, tp->hdr_len);
                 tp->size = tp->hdr_len;
             }
-        } while (split_size -= bytes);
+            split_size -= bytes;
+        } while (bytes && split_size);
     } else if (!tp->tse && tp->cptse) {
         // context descriptor TSE is not set, while data descriptor TSE is set
         DBGOUT(TXERR, "TCP segmentation error\n");
--
generated by git-patchbot for /home/xen/git/qemu-upstream-unstable.git

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog