From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754761Ab3IKEaf (ORCPT ); Wed, 11 Sep 2013 00:30:35 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:12659 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752966Ab3IKE3G (ORCPT ); Wed, 11 Sep 2013 00:29:06 -0400 X-Authority-Analysis: v=2.0 cv=ddwCLAre c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=Ciwy3NGCPMMA:10 a=RRh5V6v78Y4A:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=ls4hAc3YJ3cA:10 a=20KFwNOVAAAA:8 a=J1Y8HTJGAAAA:8 a=COH8p13WmXq63JIno7sA:9 a=jEp0ucaQiEUA:10 a=4N9Db7Z2_RYA:10 a=jeBq3FmKZ4MA:10 a=YkVESfF7KhISncSb:21 a=nlVjDGyBJ5oYXQNa:21 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-Id: <20130911042900.524278953@goodmis.org> User-Agent: quilt/0.60-1 Date: Wed, 11 Sep 2013 00:27:56 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Michael S. Tsirkin" , Jason Wang , "David S. Miller" Subject: [049/251] macvtap: correctly linearize skb when zerocopy is used References: <20130911042707.738353451@goodmis.org> Content-Disposition: inline; filename=0049-macvtap-correctly-linearize-skb-when-zerocopy-is-use.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.6.11.9-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang [ Upstream commit 61d46bf979d5cd7c164709a80ad5676a35494aae ] Userspace may produce vectors greater than MAX_SKB_FRAGS. When we try to linearize parts of the skb to let the rest of iov to be fit in the frags, we need count copylen into linear when calling macvtap_alloc_skb() instead of partly counting it into data_len. Since this breaks zerocopy_sg_from_iovec() since its inner counter assumes nr_frags should be zero at beginning. This cause nr_frags to be increased wrongly without setting the correct frags. This bug were introduced from b92946e2919134ebe2a4083e4302236295ea2a73 (macvtap: zerocopy: validate vectors before building skb). Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Steven Rostedt --- drivers/net/macvtap.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 0f0f9ce..28c8ad9 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -656,6 +656,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, int vnet_hdr_len = 0; int copylen = 0; bool zerocopy = false; + size_t linear; if (q->flags & IFF_VNET_HDR) { vnet_hdr_len = q->vnet_hdr_sz; @@ -710,11 +711,14 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, copylen = vnet_hdr.hdr_len; if (!copylen) copylen = GOODCOPY_LEN; - } else + linear = copylen; + } else { copylen = len; + linear = vnet_hdr.hdr_len; + } skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, - vnet_hdr.hdr_len, noblock, &err); + linear, noblock, &err); if (!skb) goto err; -- 1.7.10.4