From patchwork Mon Apr 16 06:08:07 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 152762 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 DBD9EB7002 for ; Mon, 16 Apr 2012 16:17:54 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751948Ab2DPGQz (ORCPT ); Mon, 16 Apr 2012 02:16:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:4690 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751744Ab2DPGQy (ORCPT ); Mon, 16 Apr 2012 02:16:54 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q3G6GmVV017824 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 16 Apr 2012 02:16:48 -0400 Received: from intel-e5620-16-2.englab.nay.redhat.com (intel-e5620-16-2.englab.nay.redhat.com [10.66.72.16]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q3G6Gjr8015710; Mon, 16 Apr 2012 02:16:46 -0400 Subject: [PATCH 3/6] macvtap: zerocopy: validate vector length before pinning user pages To: netdev@vger.kernel.org, xma@us.ibm.com, davem@davemloft.net, linux-kernel@vger.kernel.org, mst@redhat.com From: Jason Wang Cc: ebiederm@xmission.com Date: Mon, 16 Apr 2012 14:08:07 +0800 Message-ID: <20120416060807.14140.96229.stgit@intel-e5620-16-2.englab.nay.redhat.com> In-Reply-To: <20120416060749.14140.19433.stgit@intel-e5620-16-2.englab.nay.redhat.com> References: <20120416060749.14140.19433.stgit@intel-e5620-16-2.englab.nay.redhat.com> User-Agent: StGit/0.15 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.25 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Currently we do not validate the vector length before calling get_user_pages_fast(), host stack would be easily overflowed by malicious guest driver who give us a descriptor with length greater than MAX_SKB_FRAGS. Solve this problem by checking the free entries before trying to pin user pages. Signed-off-by: Jason Wang --- drivers/net/macvtap.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 7cb2684..d197a78 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -529,6 +529,8 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, } base = (unsigned long)from->iov_base + offset; size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; + if (i + size >= MAX_SKB_FRAGS) + return -EFAULT; num_pages = get_user_pages_fast(base, size, 0, &page[i]); if ((num_pages != size) || (num_pages > MAX_SKB_FRAGS - skb_shinfo(skb)->nr_frags))