Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751910AbbLIPZP (ORCPT ); Wed, 9 Dec 2015 10:25:15 -0500 Received: from mail-pa0-f41.google.com ([209.85.220.41]:34687 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751236AbbLIPZM (ORCPT ); Wed, 9 Dec 2015 10:25:12 -0500 Message-ID: <1449674706.9768.5.camel@edumazet-glaptop2.roam.corp.google.com> Subject: [PATCH net] ipv6: sctp: clone options to avoid use after free From: Eric Dumazet To: Eric Dumazet Cc: Marcelo Ricardo Leitner , Dmitry Vyukov , "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , netdev , LKML , Vlad Yasevich , Neil Horman , linux-sctp@vger.kernel.org, syzkaller , Kostya Serebryany , Alexander Potapenko , Sasha Levin Date: Wed, 09 Dec 2015 07:25:06 -0800 In-Reply-To: References: <20151209145917.GA3884@mrl.redhat.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 Content-Length: 1498 Lines: 49 From: Eric Dumazet SCTP is lacking proper np->opt cloning at accept() time. TCP and DCCP use ipv6_dup_options() helper, do the same in SCTP. We might later factorize this code in a common helper to avoid future mistakes. Reported-by: Dmitry Vyukov Signed-off-by: Eric Dumazet --- net/sctp/ipv6.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c index d28c0b4c9128..ec529121f38a 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -641,6 +641,7 @@ static struct sock *sctp_v6_create_accept_sk(struct sock *sk, struct sock *newsk; struct ipv6_pinfo *newnp, *np = inet6_sk(sk); struct sctp6_sock *newsctp6sk; + struct ipv6_txoptions *opt; newsk = sk_alloc(sock_net(sk), PF_INET6, GFP_KERNEL, sk->sk_prot, 0); if (!newsk) @@ -660,6 +661,13 @@ static struct sock *sctp_v6_create_accept_sk(struct sock *sk, memcpy(newnp, np, sizeof(struct ipv6_pinfo)); + rcu_read_lock(); + opt = rcu_dereference(np->opt); + if (opt) + opt = ipv6_dup_options(newsk, opt); + RCU_INIT_POINTER(newnp->opt, opt); + rcu_read_unlock(); + /* Initialize sk's sport, dport, rcv_saddr and daddr for getsockname() * and getpeername(). */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/