From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: [PATCH 61/75] perf header: Fix unchecked usage of strncpy() Date: Thu, 6 Dec 2018 18:25:48 -0300 Message-ID: <20181206212602.20474-62-acme@kernel.org> References: <20181206212602.20474-1-acme@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20181206212602.20474-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Ingo Molnar Cc: Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , Jiri Olsa , Namhyung Kim List-Id: linux-perf-users.vger.kernel.org From: Arnaldo Carvalho de Melo The strncpy() function may leave the destination string buffer unterminated, better use strlcpy() that we have a __weak fallback implementation for systems without it. This fixes this warning on an Alpine Linux Edge system with gcc 8.2: util/header.c: In function 'perf_event__synthesize_event_update_unit': util/header.c:3586:2: error: 'strncpy' output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation] strncpy(ev->data, evsel->unit, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ util/header.c:3579:16: note: length computed here size_t size = strlen(evsel->unit); ^~~~~~~~~~~~~~~~~~~ Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Fixes: a6e5281780d1 ("perf tools: Add event_update event unit type") Link: https://lkml.kernel.org/n/tip-fiikh5nay70bv4zskw2aa858@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/header.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 4a64739c67e7..c87cfe6b7c96 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -3583,7 +3583,7 @@ perf_event__synthesize_event_update_unit(struct perf_tool *tool, if (ev == NULL) return -ENOMEM; - strncpy(ev->data, evsel->unit, size); + strlcpy(ev->data, evsel->unit, size + 1); err = process(tool, (union perf_event *)ev, NULL, NULL); free(ev); return err; -- 2.19.2