Commit fca5085c authored Dec 06, 2018 by Arnaldo Carvalho de Melo

perf dso: Fix unchecked usage of strncpy()

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:

  In function 'decompress_kmodule',
      inlined from 'dso__decompress_kmodule_fd' at util/dso.c:305:9:
  util/dso.c:298:3: error: 'strncpy' destination unchanged after copying no bytes [-Werror=stringop-truncation]
     strncpy(pathname, tmpbuf, len);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    CC       /tmp/build/perf/util/values.o
    CC       /tmp/build/perf/util/debug.o
  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: c9a8a613 ("perf tools: Move the temp file processing into decompress_kmodule")
Link: https://lkml.kernel.org/n/tip-tl2hdxj64tt4k8btbi6a0ugw@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 15a5cd19

tools/perf/util/dso.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -295,7 +295,7 @@ static int decompress_kmodule(struct dso dso, const char name,
		unlink(tmpbuf);

		if (pathname && (fd >= 0))
		strncpy(pathname, tmpbuf, len);
		strlcpy(pathname, tmpbuf, len);

		return fd;
		}

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