From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933338Ab3GCSni (ORCPT ); Wed, 3 Jul 2013 14:43:38 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:19740 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933312Ab3GCSlM (ORCPT ); Wed, 3 Jul 2013 14:41:12 -0400 X-Authority-Analysis: v=2.0 cv=KtrPKBqN c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=Ciwy3NGCPMMA:10 a=-uxZdwyhwGYA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=rzdBI_ahBggA:10 a=tHz9FfFoAAAA:8 a=J1Y8HTJGAAAA:8 a=shfSlcufsUQO_5ujM3gA:9 a=6O0IECtVFhoA:10 a=4N9Db7Z2_RYA:10 a=jeBq3FmKZ4MA:10 a=uXlexnhggweefldZ:21 a=Lku378iiqYe7xXGe:21 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-Id: <20130703184054.761012395@goodmis.org> User-Agent: quilt/0.60-1 Date: Wed, 03 Jul 2013 14:39:58 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: David Vrabel , Wei Liu , Ian Campbell , "David S. Miller" Subject: [061/141] xen-netback: dont disconnect frontend when seeing oversize packet References: <20130703183857.307196999@goodmis.org> Content-Disposition: inline; filename=0061-xen-netback-don-t-disconnect-frontend-when-seeing-ov.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.6.11.6 stable review patch. If anyone has any objections, please let me know. ------------------ From: Wei Liu [ Upstream commit 03393fd5cc2b6cdeec32b704ecba64dbb0feae3c ] 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 Signed-off-by: Wei Liu Acked-by: Ian Campbell Signed-off-by: David S. Miller Signed-off-by: Steven Rostedt --- drivers/net/xen-netback/netback.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index d5a4e74..89dd960 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -946,12 +946,22 @@ 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; -- 1.7.10.4