From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 E929AC76186 for ; Mon, 29 Jul 2019 19:29:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBEEF2070B for ; Mon, 29 Jul 2019 19:29:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564428578; bh=/JwY3h9nUS0LG/9eBVEMdwzjPajL0hD0NRE551e2B1k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=iuKGykBl1dvbIB31nfcPmmBUi544VzQuRFsn0uD9K1ao+E4hEJuyvNtH8vW3RH2Z1 WqKq2b9qoBAcQcg0XTH6jb7m9zyoeiRnLfW/wK2xuEHDh24h3bYOJWpYeNqcLhx/+s aqlXFDBmLIzj4hzzfuS5yOobXh/Gq2PuwZQnpHCw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728494AbfG2T3h (ORCPT ); Mon, 29 Jul 2019 15:29:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:42196 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387545AbfG2T3c (ORCPT ); Mon, 29 Jul 2019 15:29:32 -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 927152171F; Mon, 29 Jul 2019 19:29:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564428571; bh=/JwY3h9nUS0LG/9eBVEMdwzjPajL0hD0NRE551e2B1k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s1a084XKqDhePyu8RnIi+yurtCbTBkSMD+2DYDUBS5ZLWFNxuzuGRvn4SDhyXvhah Xo82N/1/hDilgdTUpWfIH9AV1ecAt9HHJUzImKMEj+kX5TNXVqhfTwCK7TjIoKM7Za yuzA59VRLzGE60qknfLUsOZ/CbLQjOaEcgqjkv8k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Taehee Yoo , "David S. Miller" , Sasha Levin Subject: [PATCH 4.14 101/293] gtp: fix suspicious RCU usage Date: Mon, 29 Jul 2019 21:19:52 +0200 Message-Id: <20190729190832.381864907@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190820.321094988@linuxfoundation.org> References: <20190729190820.321094988@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit e198987e7dd7d3645a53875151cd6f8fc425b706 ] gtp_encap_enable_socket() and gtp_encap_destroy() are not protected by rcu_read_lock(). and it's not safe to write sk->sk_user_data. This patch make these functions to use lock_sock() instead of rcu_dereference_sk_user_data(). Test commands: gtp-link add gtp1 Splat looks like: [ 83.238315] ============================= [ 83.239127] WARNING: suspicious RCU usage [ 83.239702] 5.2.0-rc6+ #49 Not tainted [ 83.240268] ----------------------------- [ 83.241205] drivers/net/gtp.c:799 suspicious rcu_dereference_check() usage! [ 83.243828] [ 83.243828] other info that might help us debug this: [ 83.243828] [ 83.246325] [ 83.246325] rcu_scheduler_active = 2, debug_locks = 1 [ 83.247314] 1 lock held by gtp-link/1008: [ 83.248523] #0: 0000000017772c7f (rtnl_mutex){+.+.}, at: __rtnl_newlink+0x5f5/0x11b0 [ 83.251503] [ 83.251503] stack backtrace: [ 83.252173] CPU: 0 PID: 1008 Comm: gtp-link Not tainted 5.2.0-rc6+ #49 [ 83.253271] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 83.254562] Call Trace: [ 83.254995] dump_stack+0x7c/0xbb [ 83.255567] gtp_encap_enable_socket+0x2df/0x360 [gtp] [ 83.256415] ? gtp_find_dev+0x1a0/0x1a0 [gtp] [ 83.257161] ? memset+0x1f/0x40 [ 83.257843] gtp_newlink+0x90/0xa21 [gtp] [ 83.258497] ? __netlink_ns_capable+0xc3/0xf0 [ 83.259260] __rtnl_newlink+0xb9f/0x11b0 [ 83.260022] ? rtnl_link_unregister+0x230/0x230 [ ... ] Fixes: 1e3a3abd8b28 ("gtp: make GTP sockets in gtp_newlink optional") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/gtp.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c index dba3869b61be..2756edd84abc 100644 --- a/drivers/net/gtp.c +++ b/drivers/net/gtp.c @@ -293,12 +293,14 @@ static void gtp_encap_destroy(struct sock *sk) { struct gtp_dev *gtp; - gtp = rcu_dereference_sk_user_data(sk); + lock_sock(sk); + gtp = sk->sk_user_data; if (gtp) { udp_sk(sk)->encap_type = 0; rcu_assign_sk_user_data(sk, NULL); sock_put(sk); } + release_sock(sk); } static void gtp_encap_disable_sock(struct sock *sk) @@ -798,7 +800,8 @@ static struct sock *gtp_encap_enable_socket(int fd, int type, goto out_sock; } - if (rcu_dereference_sk_user_data(sock->sk)) { + lock_sock(sock->sk); + if (sock->sk->sk_user_data) { sk = ERR_PTR(-EBUSY); goto out_sock; } @@ -814,6 +817,7 @@ static struct sock *gtp_encap_enable_socket(int fd, int type, setup_udp_tunnel_sock(sock_net(sock->sk), sock, &tuncfg); out_sock: + release_sock(sock->sk); sockfd_put(sock); return sk; } -- 2.20.1