From patchwork Mon Aug 10 15:21:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 266627 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1BA8CC433E1 for ; Mon, 10 Aug 2020 15:38:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5FA922EBE for ; Mon, 10 Aug 2020 15:38:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597073910; bh=dK+dE3HFvoYVSktKHD4lSR0Qr1HltIXoGbfJokD2cB4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=z54r4aIITT8qEXBz29jpYMhgVfkaq03R2wu1lAGpPnSa+cW9ko0hQUbnwoFjUJDp0 Ak1bCAmfwdF/hsv4hoOtL49rEbwmPMU0jfr6fJQ/cx3oqks88ItxWH375r8m5mFG/T X4NPhohBdhdJT0eQpAtHfnghlnGkslM7yAoT8pww= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728597AbgHJPZ4 (ORCPT ); Mon, 10 Aug 2020 11:25:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:59852 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728466AbgHJPZz (ORCPT ); Mon, 10 Aug 2020 11:25:55 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3061822CF7; Mon, 10 Aug 2020 15:25:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597073154; bh=dK+dE3HFvoYVSktKHD4lSR0Qr1HltIXoGbfJokD2cB4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jf+jsbTzdJoVSYPgD4rit7iVTnP5fJdouvt6gq/K84rvB9RxDM6dfAIetpKoBwmKb imdKWz4pmLzQ90yknbCWbX5KS8Jb1dDL7sAWy9F3P3xXwZNxZSZ6dPeNyKwlNe4aE6 Rgv1NUXyOG9gsc2Mnj26al6tCRV5+zpmNjK8MdCg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Abeni , Matthieu Baerts , "David S. Miller" , Nicolas Rybowski Subject: [PATCH 5.7 76/79] mptcp: be careful on subflow creation Date: Mon, 10 Aug 2020 17:21:35 +0200 Message-Id: <20200810151815.970854393@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200810151812.114485777@linuxfoundation.org> References: <20200810151812.114485777@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paolo Abeni [ Upstream commit adf7341064982de923a1f8a11bcdec48be6b3004 ] Nicolas reported the following oops: [ 1521.392541] BUG: kernel NULL pointer dereference, address: 00000000000000c0 [ 1521.394189] #PF: supervisor read access in kernel mode [ 1521.395376] #PF: error_code(0x0000) - not-present page [ 1521.396607] PGD 0 P4D 0 [ 1521.397156] Oops: 0000 [#1] SMP PTI [ 1521.398020] CPU: 0 PID: 22986 Comm: kworker/0:2 Not tainted 5.8.0-rc4+ #109 [ 1521.399618] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 [ 1521.401728] Workqueue: events mptcp_worker [ 1521.402651] RIP: 0010:mptcp_subflow_create_socket+0xf1/0x1c0 [ 1521.403954] Code: 24 08 89 44 24 04 48 8b 7a 18 e8 2a 48 d4 ff 8b 44 24 04 85 c0 75 7a 48 8b 8b 78 02 00 00 48 8b 54 24 08 48 8d bb 80 00 00 00 <48> 8b 89 c0 00 00 00 48 89 8a c0 00 00 00 48 8b 8b 78 02 00 00 8b [ 1521.408201] RSP: 0000:ffffabc4002d3c60 EFLAGS: 00010246 [ 1521.409433] RAX: 0000000000000000 RBX: ffffa0b9ad8c9a00 RCX: 0000000000000000 [ 1521.411096] RDX: ffffa0b9ae78a300 RSI: 00000000fffffe01 RDI: ffffa0b9ad8c9a80 [ 1521.412734] RBP: ffffa0b9adff2e80 R08: ffffa0b9af02d640 R09: ffffa0b9ad923a00 [ 1521.414333] R10: ffffabc4007139f8 R11: fefefefefefefeff R12: ffffabc4002d3cb0 [ 1521.415918] R13: ffffa0b9ad91fa58 R14: ffffa0b9ad8c9f9c R15: 0000000000000000 [ 1521.417592] FS: 0000000000000000(0000) GS:ffffa0b9af000000(0000) knlGS:0000000000000000 [ 1521.419490] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1521.420839] CR2: 00000000000000c0 CR3: 000000002951e006 CR4: 0000000000160ef0 [ 1521.422511] Call Trace: [ 1521.423103] __mptcp_subflow_connect+0x94/0x1f0 [ 1521.425376] mptcp_pm_create_subflow_or_signal_addr+0x200/0x2a0 [ 1521.426736] mptcp_worker+0x31b/0x390 [ 1521.431324] process_one_work+0x1fc/0x3f0 [ 1521.432268] worker_thread+0x2d/0x3b0 [ 1521.434197] kthread+0x117/0x130 [ 1521.435783] ret_from_fork+0x22/0x30 on some unconventional configuration. The MPTCP protocol is trying to create a subflow for an unaccepted server socket. That is allowed by the RFC, even if subflow creation will likely fail. Unaccepted sockets have still a NULL sk_socket field, avoid the issue by failing earlier. Reported-and-tested-by: Nicolas Rybowski Fixes: 7d14b0d2b9b3 ("mptcp: set correct vfs info for subflows") Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/mptcp/subflow.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -999,6 +999,12 @@ int mptcp_subflow_create_socket(struct s struct socket *sf; int err; + /* un-accepted server sockets can reach here - on bad configuration + * bail early to avoid greater trouble later + */ + if (unlikely(!sk->sk_socket)) + return -EINVAL; + err = sock_create_kern(net, sk->sk_family, SOCK_STREAM, IPPROTO_TCP, &sf); if (err)