From bdf23a9a190d7ecea092fd5c4aabb7d4bd0a9980 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 8 Feb 2017 17:01:46 -0300 Subject: [PATCH] perf thread_map: Correctly size buffer used with dirent->dt_name The size of dirent->dt_name is NAME_MAX + 1, but the size for the 'path' buffer is hard coded at 256, which may truncate it because we also prepend "/proc/", so that all that into account and thank gcc 7 for this warning: /git/linux/tools/perf/util/thread_map.c: In function 'thread_map__new_by_uid': /git/linux/tools/perf/util/thread_map.c:119:39: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 250 [-Werror=format-truncation=] snprintf(path, sizeof(path), "/proc/%s", dirent->d_name); ^~ In file included from /usr/include/stdio.h:939:0, from /git/linux/tools/perf/util/thread_map.c:5: /usr/include/bits/stdio2.h:64:10: note: '__builtin___snprintf_chk' output between 7 and 262 bytes into a destination of size 256 return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ __bos (__s), __fmt, __va_arg_pack ()); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-csy0r8zrvz5efccgd4k12c82@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/thread_map.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c index f9eab20..7c3fcc5 100644 --- a/tools/perf/util/thread_map.c +++ b/tools/perf/util/thread_map.c @@ -93,7 +93,7 @@ struct thread_map *thread_map__new_by_uid(uid_t uid) { DIR *proc; int max_threads = 32, items, i; - char path[256]; + char path[NAME_MAX + 1 + 6]; struct dirent *dirent, **namelist = NULL; struct thread_map *threads = thread_map__alloc(max_threads); -- 2.7.4