4.20-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit 2f5302533f306d5ee87bd375aef9ca35b91762cb ]
The strncpy() function may leave the destination string buffer unterminated, better use strlcpy() that we have a __weak fallback implementation for systems without it.
In this specific case this would only happen if fgets() was buggy, as its man page states that it should read one less byte than the size of the destination buffer, so that it can put the nul byte at the end of it, so it would never copy 255 non-nul chars, as fgets reads into the orig buffer at most 254 non-nul chars and terminates it. But lets just switch to strlcpy to keep the original intent and silence the gcc 8.2 warning.
This fixes this warning on an Alpine Linux Edge system with gcc 8.2:
In function 'cpu_model', inlined from 'svg_cpu_box' at util/svghelper.c:378:2: util/svghelper.c:337:5: error: 'strncpy' output may be truncated copying 255 bytes from a string of length 255 [-Werror=stringop-truncation] strncpy(cpu_m, &buf[13], 255); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Cc: Adrian Hunter adrian.hunter@intel.com Cc: Jiri Olsa jolsa@kernel.org Cc: Namhyung Kim namhyung@kernel.org Cc: Arjan van de Ven arjan@linux.intel.com Fixes: f48d55ce7871 ("perf: Add a SVG helper library file") Link: https://lkml.kernel.org/n/tip-xzkoo0gyr56gej39ltivuh9g@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/svghelper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/svghelper.c b/tools/perf/util/svghelper.c index 1cbada2dc6be..f735ee038713 100644 --- a/tools/perf/util/svghelper.c +++ b/tools/perf/util/svghelper.c @@ -334,7 +334,7 @@ static char *cpu_model(void) if (file) { while (fgets(buf, 255, file)) { if (strstr(buf, "model name")) { - strncpy(cpu_m, &buf[13], 255); + strlcpy(cpu_m, &buf[13], 255); break; } }