From patchwork Fri Jan 15 18:24:15 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 568350 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 66C651401DA; Sat, 16 Jan 2016 05:29:12 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1aK97U-0000mp-Vv; Fri, 15 Jan 2016 18:29:08 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1aK92m-0007Bq-NW for kernel-team@lists.ubuntu.com; Fri, 15 Jan 2016 18:24:16 +0000 Received: from av-217-129-142-138.netvisao.pt ([217.129.142.138] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1aK92m-0001cH-Bu; Fri, 15 Jan 2016 18:24:16 +0000 From: Luis Henriques To: Eric Dumazet Subject: [3.16.y-ckt stable] Patch "udp: properly support MSG_PEEK with truncated buffers" has been added to staging queue Date: Fri, 15 Jan 2016 18:24:15 +0000 Message-Id: <1452882255-23203-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Cc: Michal Kubecek , Herbert Xu , kernel-team@lists.ubuntu.com, Ben Hutchings , "David S . Miller" X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled udp: properly support MSG_PEEK with truncated buffers to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt23. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ---8<------------------------------------------------------------ From eb98e28dee492dcf8784eeeedeb23258d9be3f4d Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 30 Dec 2015 08:51:12 -0500 Subject: udp: properly support MSG_PEEK with truncated buffers commit 197c949e7798fbf28cfadc69d9ca0c2abbf93191 upstream. Backport of this upstream commit into stable kernels : 89c22d8c3b27 ("net: Fix skb csum races when peeking") exposed a bug in udp stack vs MSG_PEEK support, when user provides a buffer smaller than skb payload. In this case, skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov); returns -EFAULT. This bug does not happen in upstream kernels since Al Viro did a great job to replace this into : skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr), msg); This variant is safe vs short buffers. For the time being, instead reverting Herbert Xu patch and add back skb->ip_summed invalid changes, simply store the result of udp_lib_checksum_complete() so that we avoid computing the checksum a second time, and avoid the problematic skb_copy_and_csum_datagram_iovec() call. This patch can be applied on recent kernels as it avoids a double checksumming, then backported to stable kernels as a bug fix. Signed-off-by: Eric Dumazet Acked-by: Herbert Xu Signed-off-by: David S. Miller Cc: Michal Kubecek Cc: Ben Hutchings [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques --- net/ipv4/udp.c | 6 ++++-- net/ipv6/udp.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 4b9e4aba11b0..c57fa4c74c94 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1272,6 +1272,7 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, int peeked, off = 0; int err; int is_udplite = IS_UDPLITE(sk); + bool checksum_valid = false; bool slow; if (flags & MSG_ERRQUEUE) @@ -1297,11 +1298,12 @@ try_again: */ if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) { - if (udp_lib_checksum_complete(skb)) + checksum_valid = !udp_lib_checksum_complete(skb); + if (!checksum_valid) goto csum_copy_err; } - if (skb_csum_unnecessary(skb)) + if (checksum_valid || skb_csum_unnecessary(skb)) err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov, copied); else { diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index eb38829d8919..e432f8eb3c60 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -389,6 +389,7 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk, int peeked, off = 0; int err; int is_udplite = IS_UDPLITE(sk); + bool checksum_valid = false; int is_udp4; bool slow; @@ -420,11 +421,12 @@ try_again: */ if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) { - if (udp_lib_checksum_complete(skb)) + checksum_valid = !udp_lib_checksum_complete(skb); + if (!checksum_valid) goto csum_copy_err; } - if (skb_csum_unnecessary(skb)) + if (checksum_valid || skb_csum_unnecessary(skb)) err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov, copied); else {