From patchwork Sun Jun 23 14:19:03 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 253563 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 487442C045C for ; Mon, 24 Jun 2013 00:18:30 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751619Ab3FWOSZ (ORCPT ); Sun, 23 Jun 2013 10:18:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:2151 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751509Ab3FWOSX (ORCPT ); Sun, 23 Jun 2013 10:18:23 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r5NEIGRg025272 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sun, 23 Jun 2013 10:18:16 -0400 Received: from redhat.com (vpn1-5-5.ams2.redhat.com [10.36.5.5]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with SMTP id r5NEIDkB005432; Sun, 23 Jun 2013 10:18:14 -0400 Date: Sun, 23 Jun 2013 17:19:03 +0300 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: "David S. Miller" , Jason Wang , Eric Dumazet , Neil Horman , netdev@vger.kernel.org, Brad Hubbard Subject: [PATCH net] tun: fix recovery from gup errors Message-ID: <20130623141903.GA21029@redhat.com> MIME-Version: 1.0 Content-Disposition: inline X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org get user pages might fail partially in tun zero copy mode. To recover we need to put all pages that we got, but code used a wrong index resulting in double-free errors. Reported-by: Brad Hubbard Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Acked-by: Neil Horman --- I haven't figured out why do we get failures, but recovery is clearly wrong. This is also -stable material. drivers/net/tun.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index bfa9bb4..c098b1e 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1010,8 +1010,9 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, return -EMSGSIZE; num_pages = get_user_pages_fast(base, size, 0, &page[i]); if (num_pages != size) { - for (i = 0; i < num_pages; i++) - put_page(page[i]); + int j; + for (j = 0; j < num_pages; j++) + put_page(page[i + j]); return -EFAULT; } truesize = size * PAGE_SIZE;