Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751992AbdFER36 (ORCPT ); Mon, 5 Jun 2017 13:29:58 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57930 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751338AbdFEQT5 (ORCPT ); Mon, 5 Jun 2017 12:19:57 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Pray3r , Andrey Konovalov , "David S. Miller" Subject: [PATCH 4.4 02/53] dccp/tcp: do not inherit mc_list from parent Date: Mon, 5 Jun 2017 18:17:00 +0200 Message-Id: <20170605153037.201779820@linuxfoundation.org> X-Mailer: git-send-email 2.13.0 In-Reply-To: <20170605153037.105331684@linuxfoundation.org> References: <20170605153037.105331684@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1338 Lines: 42 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 657831ffc38e30092a2d5f03d385d710eb88b09a ] syzkaller found a way to trigger double frees from ip_mc_drop_socket() It turns out that leave a copy of parent mc_list at accept() time, which is very bad. Very similar to commit 8b485ce69876 ("tcp: do not inherit fastopen_req from parent") Initial report from Pray3r, completed by Andrey one. Thanks a lot to them ! Signed-off-by: Eric Dumazet Reported-by: Pray3r Reported-by: Andrey Konovalov Tested-by: Andrey Konovalov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/inet_connection_sock.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -669,6 +669,8 @@ struct sock *inet_csk_clone_lock(const s inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num); newsk->sk_write_space = sk_stream_write_space; + inet_sk(newsk)->mc_list = NULL; + newsk->sk_mark = inet_rsk(req)->ir_mark; atomic64_set(&newsk->sk_cookie, atomic64_read(&inet_rsk(req)->ir_cookie));