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=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 CF766C07E85 for ; Tue, 11 Dec 2018 15:58:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 94DAB20855 for ; Tue, 11 Dec 2018 15:58:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544543913; bh=2e/IGuvrPklVs+SVlSvonoj0C2i29Ir5DHLUgZ33gRY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rcQ6+IxRU52dwZg8k0IA2j0yvY/mpKND6CLc7nFpXGlFRDnWU+or+u5UGicWg2naD XJYDFCHvYevHjFcCKmFRRsU3BrXbWRdQOD1DtNPgohLdSeAxrZOR2FvVRhEzDI4GCx 9G69pDoy9BvtqgHI2FcUuBdHCuQTR9vnSdCwsywE= DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94DAB20855 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727050AbeLKP6c (ORCPT ); Tue, 11 Dec 2018 10:58:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:47936 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731014AbeLKP62 (ORCPT ); Tue, 11 Dec 2018 10:58:28 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 EF8B32086D; Tue, 11 Dec 2018 15:58:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544543907; bh=2e/IGuvrPklVs+SVlSvonoj0C2i29Ir5DHLUgZ33gRY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aow4bzYslacsAokcBWjvqQRyKJqlC06m0oKL5fLUAvSJKHEl+BXpDKs210PhBRYxr iqlqV6ioZ6KsYok23faAhqtS/beXPETru1yv6NxW2TZN1F4lbyj6ddHk8ij6M3ODYz LVZ6KnA9DmMfg/wIMHUFWWr2WdZxlmark38yKhaQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Macpaul Lin , Daniel Thompson Subject: [PATCH 4.19 109/118] kgdboc: fix KASAN global-out-of-bounds bug in param_set_kgdboc_var() Date: Tue, 11 Dec 2018 16:42:08 +0100 Message-Id: <20181211151648.665278775@linuxfoundation.org> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20181211151644.216668863@linuxfoundation.org> References: <20181211151644.216668863@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Macpaul Lin commit dada6a43b0402eba438a17ac86fdc64ac56a4607 upstream. This patch is trying to fix KE issue due to "BUG: KASAN: global-out-of-bounds in param_set_kgdboc_var+0x194/0x198" reported by Syzkaller scan." [26364:syz-executor0][name:report8t]BUG: KASAN: global-out-of-bounds in param_set_kgdboc_var+0x194/0x198 [26364:syz-executor0][name:report&]Read of size 1 at addr ffffff900e44f95f by task syz-executor0/26364 [26364:syz-executor0][name:report&] [26364:syz-executor0]CPU: 7 PID: 26364 Comm: syz-executor0 Tainted: G W 0 [26364:syz-executor0]Call trace: [26364:syz-executor0][] dump_bacIctrace+Ox0/0x470 [26364:syz-executor0][] show_stack+0x20/0x30 [26364:syz-executor0][] dump_stack+Oxd8/0x128 [26364:syz-executor0][] print_address_description +0x80/0x4a8 [26364:syz-executor0][] kasan_report+Ox178/0x390 [26364:syz-executor0][] _asan_report_loadi_noabort+Ox18/0x20 [26364:syz-executor0][] param_set_kgdboc_var+Ox194/0x198 [26364:syz-executor0][] param_attr_store+Ox14c/0x270 [26364:syz-executor0][] module_attr_store+0x60/0x90 [26364:syz-executor0][] sysfs_kl_write+Ox100/0x158 [26364:syz-executor0][] kernfs_fop_write+0x27c/0x3a8 [26364:syz-executor0][] do_loop_readv_writev+0x114/0x1b0 [26364:syz-executor0][] do_readv_writev+0x4f8/0x5e0 [26364:syz-executor0][] vfs_writev+0x7c/Oxb8 [26364:syz-executor0][] SyS_writev+Oxcc/0x208 [26364:syz-executor0][] elO_svc_naked +0x24/0x28 [26364:syz-executor0][name:report&] [26364:syz-executor0][name:report&]The buggy address belongs to the variable: [26364:syz-executor0][name:report&] kgdb_tty_line+Ox3f/0x40 [26364:syz-executor0][name:report&] [26364:syz-executor0][name:report&]Memory state around the buggy address: [26364:syz-executor0] ffffff900e44f800: 00 00 00 00 00 04 fa fa fa fa fa fa 00 fa fa fa [26364:syz-executor0] ffffff900e44f880: fa fa fa fa 00 fa fa fa fa fa fa fa 00 fa fa fa [26364:syz-executor0]> ffffff900e44f900: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00 [26364:syz-executor0][name:report&] ^ [26364:syz-executor0] ffffff900e44f980: 00 fa fa fa fa fa fa fa 04 fa fa fa fa fa fa fa [26364:syz-executor0] ffffff900e44fa00: 04 fa fa fa fa fa fa fa 00 fa fa fa fa fa fa fa [26364:syz-executor0][name:report&] [26364:syz-executor0][name:panic&]Disabling lock debugging due to kernel taint [26364:syz-executor0]------------[cut here]------------ After checking the source code, we've found there might be an out-of-bounds access to "config[len - 1]" array when the variable "len" is zero. Signed-off-by: Macpaul Lin Acked-by: Daniel Thompson Cc: stable Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/kgdboc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/tty/serial/kgdboc.c +++ b/drivers/tty/serial/kgdboc.c @@ -230,7 +230,7 @@ static void kgdboc_put_char(u8 chr) static int param_set_kgdboc_var(const char *kmessage, const struct kernel_param *kp) { - int len = strlen(kmessage); + size_t len = strlen(kmessage); if (len >= MAX_CONFIG_LEN) { printk(KERN_ERR "kgdboc: config string too long\n"); @@ -252,7 +252,7 @@ static int param_set_kgdboc_var(const ch strcpy(config, kmessage); /* Chop out \n char as a result of echo */ - if (config[len - 1] == '\n') + if (len && config[len - 1] == '\n') config[len - 1] = '\0'; if (configured == 1)