From patchwork Thu Dec 10 14:26:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 341934 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, 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 814A4C433FE for ; Thu, 10 Dec 2020 14:28:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3B77F23D57 for ; Thu, 10 Dec 2020 14:28:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390154AbgLJO2n (ORCPT ); Thu, 10 Dec 2020 09:28:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:36422 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726013AbgLJO2j (ORCPT ); Thu, 10 Dec 2020 09:28:39 -0500 From: Greg Kroah-Hartman Authentication-Results: mail.kernel.org; dkim=permerror (bad message/signature format) To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Paulo Alcantara (SUSE)" , Ronnie Sahlberg , Steve French Subject: [PATCH 4.4 26/39] cifs: fix potential use-after-free in cifs_echo_request() Date: Thu, 10 Dec 2020 15:26:37 +0100 Message-Id: <20201210142602.188747692@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201210142600.887734129@linuxfoundation.org> References: <20201210142600.887734129@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paulo Alcantara commit 212253367dc7b49ed3fc194ce71b0992eacaecf2 upstream. This patch fixes a potential use-after-free bug in cifs_echo_request(). For instance, thread 1 -------- cifs_demultiplex_thread() clean_demultiplex_info() kfree(server) thread 2 (workqueue) -------- apic_timer_interrupt() smp_apic_timer_interrupt() irq_exit() __do_softirq() run_timer_softirq() call_timer_fn() cifs_echo_request() <- use-after-free in server ptr Signed-off-by: Paulo Alcantara (SUSE) CC: Stable Reviewed-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/cifs/connect.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -783,6 +783,8 @@ static void clean_demultiplex_info(struc list_del_init(&server->tcp_ses_list); spin_unlock(&cifs_tcp_ses_lock); + cancel_delayed_work_sync(&server->echo); + spin_lock(&GlobalMid_Lock); server->tcpStatus = CifsExiting; spin_unlock(&GlobalMid_Lock);