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,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 CD63DC33CA3 for ; Sat, 11 Jan 2020 10:03:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A1FC020848 for ; Sat, 11 Jan 2020 10:03:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578737034; bh=R3F0oxfs8gfJYmPuvUSgnD2wieukgLsd+9x58Xcb2FU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=d3jJjrW7+oJt4a8izCfC8txIOH4ZEXEPyOwZmUfwwCTcr8Gpo5VxOVTfrJOoj+DLV Ktwl68DQtrd70m2QXU8rrEsiqCLy0ap+F3H5jVtk0QieRFUGvAd0COuVcHW6SOqNkm uvdDfoJKX97IxWLFWebx1riIpLzETfSXMGM0Z1UQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729477AbgAKKDx (ORCPT ); Sat, 11 Jan 2020 05:03:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:35554 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728850AbgAKKDw (ORCPT ); Sat, 11 Jan 2020 05:03:52 -0500 Received: from localhost (unknown [62.119.166.9]) (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 A707220866; Sat, 11 Jan 2020 10:03:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578737031; bh=R3F0oxfs8gfJYmPuvUSgnD2wieukgLsd+9x58Xcb2FU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1Bm8T6DtpnyRszpHfBSvV+9cpzQFMRpcjI8CEN9VGkOeczY1dPsM6XPJE5dnD2AP2 sEAnKpR+hFcDOEBqnZw4swEK99FZxCChUVCv3/milhKq+SL3VUILCKfrOBczlkQlhn 0K3f8g594XK0Bix9qzfmMW2qkVWftHxcRAVVl6Q0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+611164843bd48cc2190c@syzkaller.appspotmail.com, David Howells , "David S. Miller" , Sasha Levin Subject: [PATCH 4.9 49/91] rxrpc: Fix possible NULL pointer access in ICMP handling Date: Sat, 11 Jan 2020 10:49:42 +0100 Message-Id: <20200111094903.559798696@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200111094844.748507863@linuxfoundation.org> References: <20200111094844.748507863@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 From: David Howells [ Upstream commit f0308fb0708078d6c1d8a4d533941a7a191af634 ] If an ICMP packet comes in on the UDP socket backing an AF_RXRPC socket as the UDP socket is being shut down, rxrpc_error_report() may get called to deal with it after sk_user_data on the UDP socket has been cleared, leading to a NULL pointer access when this local endpoint record gets accessed. Fix this by just returning immediately if sk_user_data was NULL. The oops looks like the following: #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page ... RIP: 0010:rxrpc_error_report+0x1bd/0x6a9 ... Call Trace: ? sock_queue_err_skb+0xbd/0xde ? __udp4_lib_err+0x313/0x34d __udp4_lib_err+0x313/0x34d icmp_unreach+0x1ee/0x207 icmp_rcv+0x25b/0x28f ip_protocol_deliver_rcu+0x95/0x10e ip_local_deliver+0xe9/0x148 __netif_receive_skb_one_core+0x52/0x6e process_backlog+0xdc/0x177 net_rx_action+0xf9/0x270 __do_softirq+0x1b6/0x39a ? smpboot_register_percpu_thread+0xce/0xce run_ksoftirqd+0x1d/0x42 smpboot_thread_fn+0x19e/0x1b3 kthread+0xf1/0xf6 ? kthread_delayed_work_timer_fn+0x83/0x83 ret_from_fork+0x24/0x30 Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Reported-by: syzbot+611164843bd48cc2190c@syzkaller.appspotmail.com Signed-off-by: David Howells Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/rxrpc/peer_event.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c index bf13b8470c9a..80950a4384aa 100644 --- a/net/rxrpc/peer_event.c +++ b/net/rxrpc/peer_event.c @@ -148,6 +148,9 @@ void rxrpc_error_report(struct sock *sk) struct rxrpc_peer *peer; struct sk_buff *skb; + if (unlikely(!local)) + return; + _enter("%p{%d}", sk, local->debug_id); skb = sock_dequeue_err_skb(sk); -- 2.20.1