@@ -975,12 +975,22 @@ static int netbk_count_requests(struct xenvif *vif,
memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots),
sizeof(*txp));
- if (txp->size > first->size) {
- netdev_err(vif->dev,
- "Invalid tx request, slot size %u > remaining size %u\n",
- txp->size, first->size);
- netbk_fatal_tx_err(vif);
- return -EIO;
+
+ /* If the guest submitted a frame >= 64 KiB then
+ * first->size overflowed and following slots will
+ * appear to be larger than the frame.
+ *
+ * This cannot be fatal error as there are buggy
+ * frontends that do this.
+ *
+ * Consume all slots and drop the packet.
+ */
+ if (!drop_err && txp->size > first->size) {
+ if (net_ratelimit())
+ netdev_dbg(vif->dev,
+ "Invalid tx request, slot size %u > remaining size %u\n",
+ txp->size, first->size);
+ drop_err = -EIO;
}
first->size -= txp->size;
This is a note to let you know that I have just added a patch titled xen-netback: don't disconnect frontend when seeing oversize packet to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.4. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 5c38697aec31e83ba53da34b15be921c2059fa8b Mon Sep 17 00:00:00 2001 From: Wei Liu <wei.liu2@citrix.com> Date: Mon, 22 Apr 2013 02:20:43 +0000 Subject: xen-netback: don't disconnect frontend when seeing oversize packet commit 03393fd5cc2b6cdeec32b704ecba64dbb0feae3c upstream. Some frontend drivers are sending packets > 64 KiB in length. This length overflows the length field in the first slot making the following slots have an invalid length. Turn this error back into a non-fatal error by dropping the packet. To avoid having the following slots having fatal errors, consume all slots in the packet. This does not reopen the security hole in XSA-39 as if the packet as an invalid number of slots it will still hit fatal error case. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Wei Liu <wei.liu2@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/net/xen-netback/netback.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) -- 1.8.1.2