queue-4.9/perf-header-fix-unchecked-usage-of-strncpy.patch

   1 From 5192bde7d98c99f2cd80225649e3c2e7493722f7 Mon Sep 17 00:00:00 2001
   2 From: Arnaldo Carvalho de Melo <acme@redhat.com>
   3 Date: Thu, 6 Dec 2018 11:09:46 -0300
   4 Subject: perf header: Fix unchecked usage of strncpy()
   5
   6 From: Arnaldo Carvalho de Melo <acme@redhat.com>
   7
   8 commit 5192bde7d98c99f2cd80225649e3c2e7493722f7 upstream.
   9
  10 The strncpy() function may leave the destination string buffer
  11 unterminated, better use strlcpy() that we have a __weak fallback
  12 implementation for systems without it.
  13
  14 This fixes this warning on an Alpine Linux Edge system with gcc 8.2:
  15
  16   util/header.c: In function 'perf_event__synthesize_event_update_name':
  17   util/header.c:3625:2: error: 'strncpy' output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation]
  18     strncpy(ev->data, evsel->name, len);
  19     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  20   util/header.c:3618:15: note: length computed here
  21     size_t len = strlen(evsel->name);
  22                  ^~~~~~~~~~~~~~~~~~~
  23
  24 Cc: Adrian Hunter <adrian.hunter@intel.com>
  25 Cc: Jiri Olsa <jolsa@kernel.org>
  26 Cc: Namhyung Kim <namhyung@kernel.org>
  27 Fixes: a6e5281780d1 ("perf tools: Add event_update event unit type")
  28 Link: https://lkml.kernel.org/n/tip-wycz66iy8dl2z3yifgqf894p@git.kernel.org
  29 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
  30 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  31
  32 ---
  33  tools/perf/util/header.c |    2 +-
  34  1 file changed, 1 insertion(+), 1 deletion(-)
  35
  36 --- a/tools/perf/util/header.c
  37 +++ b/tools/perf/util/header.c
  38 @@ -3027,7 +3027,7 @@ perf_event__synthesize_event_update_name
  39         if (ev == NULL)
  40                 return -ENOMEM;
  41
  42 -       strncpy(ev->data, evsel->name, len);
  43 +       strlcpy(ev->data, evsel->name, len + 1);
  44         err = process(tool, (union perf_event*) ev, NULL, NULL);
  45         free(ev);
  46         return err;