From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763055AbcALQ6F (ORCPT ); Tue, 12 Jan 2016 11:58:05 -0500 Received: from mail-pa0-f51.google.com ([209.85.220.51]:36120 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761778AbcALQ6D (ORCPT ); Tue, 12 Jan 2016 11:58:03 -0500 Message-ID: <1452617880.1223.21.camel@edumazet-glaptop2.roam.corp.google.com> Subject: [PATCH net] phonet: properly unshare skbs in phonet_rcv() From: Eric Dumazet To: Ivaylo Dimitrov , Remi Denis-Courmont Cc: Salam Noureddine , "David S. Miller" , Pali =?ISO-8859-1?Q?Roh=E1r?= , Network Development , LKML , Sebastian Reichel , "linux-omap@vger.kernel.org" Date: Tue, 12 Jan 2016 08:58:00 -0800 In-Reply-To: <1452608377.1223.13.camel@edumazet-glaptop2.roam.corp.google.com> References: <568EA671.7000502@gmail.com> <56929985.3020502@gmail.com> <1452457610.16445.13.camel@edumazet-glaptop2.roam.corp.google.com> <5694188F.80907@gmail.com> <56944DFA.4050002@gmail.com> <1452560786.1223.6.camel@edumazet-glaptop2.roam.corp.google.com> <1452565288.1223.10.camel@edumazet-glaptop2.roam.corp.google.com> <1452565515.1223.11.camel@edumazet-glaptop2.roam.corp.google.com> <5694A840.8030900@gmail.com> <1452608377.1223.13.camel@edumazet-glaptop2.roam.corp.google.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet Ivaylo Dimitrov reported a regression caused by commit 7866a621043f ("dev: add per net_device packet type chains"). skb->dev becomes NULL and we crash in __netif_receive_skb_core(). Before above commit, different kind of bugs or corruptions could happen without major crash. But the root cause is that phonet_rcv() can queue skb without checking if skb is shared or not. Many thanks to Ivaylo Dimitrov for his help, diagnosis and tests. Reported-by: Ivaylo Dimitrov Tested-by: Ivaylo Dimitrov Signed-off-by: Eric Dumazet Cc: Remi Denis-Courmont --- net/phonet/af_phonet.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c index 10d42f3220ab..f925753668a7 100644 --- a/net/phonet/af_phonet.c +++ b/net/phonet/af_phonet.c @@ -377,6 +377,10 @@ static int phonet_rcv(struct sk_buff *skb, struct net_device *dev, struct sockaddr_pn sa; u16 len; + skb = skb_share_check(skb, GFP_ATOMIC); + if (!skb) + return NET_RX_DROP; + /* check we have at least a full Phonet header */ if (!pskb_pull(skb, sizeof(struct phonethdr))) goto out;