This is a note to let you know that I've just added the patch titled
xen-netback: don't disconnect frontend when seeing oversize packet
to the 3.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-netback-don-t-disconnect-frontend-when-seeing-oversize-packet.patch
and it can be found in the queue-3.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 03393fd5cc2b6cdeec32b704ecba64dbb0feae3c Mon Sep 17 00:00:00 2001
From: Wei Liu <wei.liu2@xxxxxxxxxx>
Date: Mon, 22 Apr 2013 02:20:43 +0000
Subject: xen-netback: don't disconnect frontend when seeing oversize packet
From: Wei Liu <wei.liu2@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/xen-netback/netback.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -975,12 +975,22 @@ static int netbk_count_requests(struct x
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;
Patches currently in stable-queue which might be from wei.liu2@xxxxxxxxxx are
queue-3.9/xen-netback-coalesce-slots-in-tx-path-and-fix-regressions.patch
queue-3.9/xen-netback-remove-redundent-parameter-in-netbk_count_requests.patch
queue-3.9/xen-netback-remove-skb-in-xen_netbk_alloc_page.patch
queue-3.9/xen-netback-don-t-disconnect-frontend-when-seeing-oversize-packet.patch
queue-3.9/xen-netback-avoid-allocating-variable-size-array-on-stack.patch
queue-3.9/xen-netfront-reduce-gso_max_size-to-account-for-max-tcp-header.patch
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