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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 46419ECE560 for ; Sat, 22 Sep 2018 15:41:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E1394206B7 for ; Sat, 22 Sep 2018 15:41:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E1394206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=windriver.com 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 S1728906AbeIVVfK (ORCPT ); Sat, 22 Sep 2018 17:35:10 -0400 Received: from mail.windriver.com ([147.11.1.11]:33293 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728534AbeIVVfK (ORCPT ); Sat, 22 Sep 2018 17:35:10 -0400 Received: from ALA-HCB.corp.ad.wrs.com ([147.11.189.41]) by mail.windriver.com (8.15.2/8.15.1) with ESMTPS id w8MFf6U8016784 (version=TLSv1 cipher=AES128-SHA bits=128 verify=FAIL); Sat, 22 Sep 2018 08:41:06 -0700 (PDT) Received: from pek-lpg-core2.corp.ad.wrs.com (128.224.153.41) by ALA-HCB.corp.ad.wrs.com (147.11.189.41) with Microsoft SMTP Server id 14.3.408.0; Sat, 22 Sep 2018 08:40:53 -0700 From: To: , , , , Subject: [PATCH v3 1/2] printk: Fix panic caused by passing log_buf_len to command line Date: Sat, 22 Sep 2018 23:40:51 +0800 Message-ID: <1537630852-247674-1-git-send-email-zhe.he@windriver.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: He Zhe log_buf_len_setup does not check input argument before passing it to simple_strtoull. The argument would be a NULL pointer if "log_buf_len", without its value, is set in command line and thus causes the following panic. PANIC: early exception 0xe3 IP 10:ffffffffaaeacd0d error 0 cr2 0x0 [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc4-yocto-standard+ #1 [ 0.000000] RIP: 0010:_parse_integer_fixup_radix+0xd/0x70 ... [ 0.000000] Call Trace: [ 0.000000] simple_strtoull+0x29/0x70 [ 0.000000] memparse+0x26/0x90 [ 0.000000] log_buf_len_setup+0x17/0x22 [ 0.000000] do_early_param+0x57/0x8e [ 0.000000] parse_args+0x208/0x320 [ 0.000000] ? rdinit_setup+0x30/0x30 [ 0.000000] parse_early_options+0x29/0x2d [ 0.000000] ? rdinit_setup+0x30/0x30 [ 0.000000] parse_early_param+0x36/0x4d [ 0.000000] setup_arch+0x336/0x99e [ 0.000000] start_kernel+0x6f/0x4ee [ 0.000000] x86_64_start_reservations+0x24/0x26 [ 0.000000] x86_64_start_kernel+0x6f/0x72 [ 0.000000] secondary_startup_64+0xa4/0xb0 This patch adds a check to prevent the panic. Signed-off-by: He Zhe Cc: stable@vger.kernel.org Cc: pmladek@suse.com Cc: sergey.senozhatsky@gmail.com Cc: rostedt@goodmis.org --- v2: Split out the addition of pr_fmt and the unsigned update v3: Use more clear error info Change unsigned to unsigned in to avoid checkpatch.pl warning kernel/printk/printk.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 9bf5404..d9821c0 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1048,7 +1048,14 @@ static void __init log_buf_len_update(unsigned size) /* save requested log_buf_len since it's too early to process it */ static int __init log_buf_len_setup(char *str) { - unsigned size = memparse(str, &str); + unsigned int size; + + if (!str) { + pr_err("boot command line parameter value not provided\n"); + return -EINVAL; + } + + size = memparse(str, &str); log_buf_len_update(size); -- 2.7.4