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 8F55FC43382 for ; Thu, 27 Sep 2018 22:47:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 513D7216E3 for ; Thu, 27 Sep 2018 22:47:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 513D7216E3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=canonical.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 S1727840AbeI1FHk (ORCPT ); Fri, 28 Sep 2018 01:07:40 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:49935 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725924AbeI1FHk (ORCPT ); Fri, 28 Sep 2018 01:07:40 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1g5f3k-0001a3-NU; Thu, 27 Sep 2018 22:47:00 +0000 From: Colin King To: Steven Rostedt , Ingo Molnar Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] tracing: fix potential null pointer dereference on rctr_end Date: Thu, 27 Sep 2018 23:47:00 +0100 Message-Id: <20180927224700.13739-1-colin.king@canonical.com> X-Mailer: git-send-email 2.17.1 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: Colin Ian King Currently rctr_end may assigned null if strchr() fails leading to a null pointer dereference in the following check on *(rctr_end + 1). Fix this by also adding a null pointer check before the dereference. Detected by CoverityScan, CID#1473700 ("Dereference null return value") Fixes: 1cc33161a83d ("uprobes: Support SDT markers having reference count (semaphore)") Signed-off-by: Colin Ian King --- kernel/trace/trace_uprobe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 3a7c73c40007..c5514651e61f 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -477,7 +477,7 @@ static int create_trace_uprobe(int argc, char **argv) rctr = strchr(arg, '('); if (rctr) { rctr_end = strchr(rctr, ')'); - if (rctr > rctr_end || *(rctr_end + 1) != 0) { + if (!rctr_end || rctr > rctr_end || *(rctr_end + 1) != 0) { ret = -EINVAL; pr_info("Invalid reference counter offset.\n"); goto fail_address_parse; -- 2.17.1