perf evlist: Validate that mmap_pages is not too big

Amend perf_evlist__parse_mmap_pages() to check that the mmap_pages
entered via the --mmap_pages/-m option is not too big.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1382427258-17495-15-git-send-email-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evlist.c

@@ -698,7 +698,8 @@ static size_t perf_evlist__mmap_size(unsigned long pages)
 int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
 				  int unset __maybe_unused)
 {
-	unsigned int pages, val, *mmap_pages = opt->value;
+	unsigned int *mmap_pages = opt->value;
+	unsigned long pages, val;
 	size_t size;
 	static struct parse_tag tags[] = {
 		{ .tag  = 'B', .mult = 1       },
@@ -709,12 +710,12 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
 	};
 
 	val = parse_tag_value(str, tags);
-	if (val != (unsigned int) -1) {
+	if (val != (unsigned long) -1) {
 		/* we got file size value */
 		pages = PERF_ALIGN(val, page_size) / page_size;
-		if (!is_power_of_2(pages)) {
+		if (pages < (1UL << 31) && !is_power_of_2(pages)) {
 			pages = next_pow2(pages);
-			pr_info("rounding mmap pages size to %u (%u pages)\n",
+			pr_info("rounding mmap pages size to %lu (%lu pages)\n",
 				pages * page_size, pages);
 		}
 	} else {
@@ -727,6 +728,11 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
 		}
 	}
 
+	if (pages > UINT_MAX || pages > SIZE_MAX / page_size) {
+		pr_err("--mmap_pages/-m value too big\n");
+		return -1;
+	}
+
 	size = perf_evlist__mmap_size(pages);
 	if (!size) {
 		pr_err("--mmap_pages/-m value must be a power of two.");