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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 9DD95C5CFE7 for ; Tue, 10 Jul 2018 18:27:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6DB5F20936 for ; Tue, 10 Jul 2018 18:27:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6DB5F20936 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.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 S1733140AbeGJS1f (ORCPT ); Tue, 10 Jul 2018 14:27:35 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:36706 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1733117AbeGJS1d (ORCPT ); Tue, 10 Jul 2018 14:27:33 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9D33E808255B; Tue, 10 Jul 2018 18:27:22 +0000 (UTC) Received: from cervelo.rdu.redhat.com (dhcp129-44.rdu.redhat.com [10.13.129.44]) by smtp.corp.redhat.com (Postfix) with ESMTP id 73D291C5A6; Tue, 10 Jul 2018 18:27:22 +0000 (UTC) From: William Cohen To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org Cc: alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, William Cohen Subject: [PATCH] Check jvmti_agent snprintf return value to avoid build failures with GCC-8.1.1 Date: Tue, 10 Jul 2018 14:27:16 -0400 Message-Id: <20180710182716.21801-1-wcohen@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 10 Jul 2018 18:27:22 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 10 Jul 2018 18:27:22 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'wcohen@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Newer versions of GCC perform static analysis to determine whether string truncation is possible with functions such as snprintf and provide a warning if truncation could occur. The make for jvmti_agent.c uses the compiler option that treats any compiler warnings as compiler errors. For GCC-8.1.1 in Fedora 28 this causes the build to fail. The return value of the snprint is now checked to ensure snprintf produced a NULL-terminated string. If the string for the path is invalid, the code does attempt to use the string. Signed-off-by: William Cohen --- tools/perf/jvmti/jvmti_agent.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/tools/perf/jvmti/jvmti_agent.c b/tools/perf/jvmti/jvmti_agent.c index 0c6d1002b524..30f14eafe4b3 100644 --- a/tools/perf/jvmti/jvmti_agent.c +++ b/tools/perf/jvmti/jvmti_agent.c @@ -227,7 +227,7 @@ void *jvmti_open(void) { char dump_path[PATH_MAX]; struct jitheader header; - int fd; + int retlen, fd; FILE *fp; init_arch_timestamp(); @@ -249,7 +249,10 @@ void *jvmti_open(void) /* * jitdump file name */ - snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", jit_path, getpid()); + retlen = snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", + jit_path, getpid()); + if (retlen <= 0 || ((int) sizeof(dump_path)) <= retlen) + return NULL; fd = open(dump_path, O_CREAT|O_TRUNC|O_RDWR, 0666); if (fd == -1) -- 2.17.1