Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753048AbdFGXEe (ORCPT ); Wed, 7 Jun 2017 19:04:34 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:50537 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752986AbdFGXE2 (ORCPT ); Wed, 7 Jun 2017 19:04:28 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Eric Dumazet , "David S . Miller" , Willy Tarreau Subject: [PATCH 3.10 249/250] dccp/tcp: do not inherit mc_list from parent Date: Thu, 8 Jun 2017 01:00:35 +0200 Message-Id: <1496876436-32402-250-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1496876436-32402-1-git-send-email-w@1wt.eu> References: <1496876436-32402-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1323 Lines: 40 From: Eric Dumazet commit 657831ffc38e30092a2d5f03d385d710eb88b09a upstream. 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: Willy Tarreau --- net/ipv4/inet_connection_sock.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 6acb541..40ac1e2 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -688,6 +688,8 @@ struct sock *inet_csk_clone_lock(const struct sock *sk, inet_sk(newsk)->inet_sport = inet_rsk(req)->loc_port; newsk->sk_write_space = sk_stream_write_space; + inet_sk(newsk)->mc_list = NULL; + newicsk->icsk_retransmits = 0; newicsk->icsk_backoff = 0; newicsk->icsk_probes_out = 0; -- 2.8.0.rc2.1.gbe9624a