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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 76FEDC43603 for ; Sun, 8 Dec 2019 13:57:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 579E8206F4 for ; Sun, 8 Dec 2019 13:57:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727297AbfLHN5o (ORCPT ); Sun, 8 Dec 2019 08:57:44 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:60156 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726718AbfLHNym (ORCPT ); Sun, 8 Dec 2019 08:54:42 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1idx1D-0007em-87; Sun, 08 Dec 2019 13:54:39 +0000 Received: from ben by deadeye with local (Exim 4.93-RC1) (envelope-from ) id 1idx1C-0002Ng-9e; Sun, 08 Dec 2019 13:54:38 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Sebastian Ott" , "Vasily Gorbik" Date: Sun, 08 Dec 2019 13:53:25 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 41/72] s390/cio: avoid calling strlen on null pointer In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.79-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Vasily Gorbik commit ea298e6ee8b34b3ed4366be7eb799d0650ebe555 upstream. Fix the following kasan finding: BUG: KASAN: global-out-of-bounds in ccwgroup_create_dev+0x850/0x1140 Read of size 1 at addr 0000000000000000 by task systemd-udevd.r/561 CPU: 30 PID: 561 Comm: systemd-udevd.r Tainted: G B Hardware name: IBM 3906 M04 704 (LPAR) Call Trace: ([<0000000231b3db7e>] show_stack+0x14e/0x1a8) [<0000000233826410>] dump_stack+0x1d0/0x218 [<000000023216fac4>] print_address_description+0x64/0x380 [<000000023216f5a8>] __kasan_report+0x138/0x168 [<00000002331b8378>] ccwgroup_create_dev+0x850/0x1140 [<00000002332b618a>] group_store+0x3a/0x50 [<00000002323ac706>] kernfs_fop_write+0x246/0x3b8 [<00000002321d409a>] vfs_write+0x132/0x450 [<00000002321d47da>] ksys_write+0x122/0x208 [<0000000233877102>] system_call+0x2a6/0x2c8 Triggered by: openat(AT_FDCWD, "/sys/bus/ccwgroup/drivers/qeth/group", O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0666) = 16 write(16, "0.0.bd00,0.0.bd01,0.0.bd02", 26) = 26 The problem is that __get_next_id in ccwgroup_create_dev might set "buf" buffer pointer to NULL and explicit check for that is required. Reviewed-by: Sebastian Ott Signed-off-by: Vasily Gorbik Signed-off-by: Ben Hutchings --- drivers/s390/cio/ccwgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/s390/cio/ccwgroup.c +++ b/drivers/s390/cio/ccwgroup.c @@ -369,7 +369,7 @@ int ccwgroup_create_dev(struct device *p goto error; } /* Check for trailing stuff. */ - if (i == num_devices && strlen(buf) > 0) { + if (i == num_devices && buf && strlen(buf) > 0) { rc = -EINVAL; goto error; }