diff options
| author | Wei Liu <wei.liu2@citrix.com> | 2013-04-22 02:20:43 +0000 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-06-19 02:16:43 +0100 |
| commit | 276d632e34fcf94042dd4182e4398a8b6cbdc07f (patch) | |
| tree | 90e66a0a9ccd6dc7f3cb675af6606f451c90a526 /drivers/net | |
| parent | bccc108d67244797827c61870e12d84f66a212fe (diff) | |
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: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/xen-netback/netback.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 467410f02adc..87dd2bf4f290 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -947,12 +947,22 @@ 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; |