From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754779Ab3IKEah (ORCPT ); Wed, 11 Sep 2013 00:30:37 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:26368 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752956Ab3IKE3G (ORCPT ); Wed, 11 Sep 2013 00:29:06 -0400 X-Authority-Analysis: v=2.0 cv=fJG7LOme c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=Ciwy3NGCPMMA:10 a=0e6gR9K7iGkA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=WZ6_UgRw9AIA:10 a=20KFwNOVAAAA:8 a=J1Y8HTJGAAAA:8 a=COH8p13WmXq63JIno7sA:9 a=jEp0ucaQiEUA:10 a=4N9Db7Z2_RYA:10 a=jeBq3FmKZ4MA:10 a=xeakZP66ru9tOW8-:21 a=_eY4gYS8kAyocr-J:21 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-Id: <20130911042900.362019501@goodmis.org> User-Agent: quilt/0.60-1 Date: Wed, 11 Sep 2013 00:27:55 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Michael S. Tsirkin" , Jason Wang , "David S. Miller" Subject: [048/251] tuntap: correctly linearize skb when zerocopy is used References: <20130911042707.738353451@goodmis.org> Content-Disposition: inline; filename=0048-tuntap-correctly-linearize-skb-when-zerocopy-is-used.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 3dd5c3308e8b671e8e8882ba972f51cefbe9fd0d ] 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 tun_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 0690899b4d4501b3505be069b9a687e68ccbe15b (tun: experimental zero copy tx support) 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/tun.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index ef7710f..ad08dee 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -692,7 +692,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control, { struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; struct sk_buff *skb; - size_t len = total_len, align = NET_SKB_PAD; + size_t len = total_len, align = NET_SKB_PAD, linear; struct virtio_net_hdr gso = { 0 }; int offset = 0; int copylen; @@ -755,10 +755,14 @@ static ssize_t tun_get_user(struct tun_struct *tun, void *msg_control, copylen = gso.hdr_len; if (!copylen) copylen = GOODCOPY_LEN; - } else + linear = copylen; + } else { copylen = len; + linear = gso.hdr_len; + } skb = tun_alloc_skb(tun, align, copylen, gso.hdr_len, noblock); + skb = tun_alloc_skb(tun, align, copylen, linear, noblock); if (IS_ERR(skb)) { if (PTR_ERR(skb) != -EAGAIN) tun->dev->stats.rx_dropped++; -- 1.7.10.4