[PATCH 67/75] perf parse-events: Fix unchecked usage of strncpy()

Arnaldo Carvalho de Melo
2018-12-06T21:30:59Z

From: Arnaldo Carvalho de Melo <acme@redhat.com>

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/parse-events.c: In function 'print_symbol_events':
util/parse-events.c:2465:4: error: 'strncpy' specified bound 100 equals destination size [-Werror=stringop-truncation]
strncpy(name, syms->symbol, MAX_NAME_LEN);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'print_symbol_events.constprop',
inlined from 'print_events' at util/parse-events.c:2508:2:
util/parse-events.c:2465:4: error: 'strncpy' specified bound 100 equals destination size [-Werror=stringop-truncation]
strncpy(name, syms->symbol, MAX_NAME_LEN);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'print_symbol_events.constprop',
inlined from 'print_events' at util/parse-events.c:2511:2:
util/parse-events.c:2465:4: error: 'strncpy' specified bound 100 equals destination size [-Werror=stringop-truncation]
strncpy(name, syms->symbol, MAX_NAME_LEN);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 947b4ad1d198 ("perf list: Fix max event string size")
Link: https://lkml.kernel.org/n/tip-b663e33bm6x8hrkie4uxh7u2@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/parse-events.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 59be3466d64d..920e1e6551dd 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -2462,7 +2462,7 @@ void print_symbol_events(const char *event_glob, unsigned type,
if (!name_only && strlen(syms->alias))
snprintf(name, MAX_NAME_LEN, "%s OR %s", syms->symbol, syms->alias);
else
- strncpy(name, syms->symbol, MAX_NAME_LEN);
+ strlcpy(name, syms->symbol, MAX_NAME_LEN);

evt_list[evt_i] = strdup(name);
if (evt_list[evt_i] == NULL)
--
2.19.2