perf annotate: Prevent overflow in size calculation

A large enough symbol size causes an overflow in the size parameter to
the histogram allocation, leading to a segfault in
symbol__inc_addr_samples later on when this histogram is accessed.

In the case of being called via perf-report, this returns back and
gracefully ignores the sample, eventually ignoring the chained return
value of perf_session_deliver_event in flush_sample_queue.

Signed-off-by: Cody Schafer <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sukadev Bhattiprolu <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/perf/util/annotate.c

@@ -426,7 +426,18 @@ int symbol__alloc_hist(struct symbol *sym)
 {
 	struct annotation *notes = symbol__annotation(sym);
 	const size_t size = symbol__size(sym);
-	size_t sizeof_sym_hist = (sizeof(struct sym_hist) + size * sizeof(u64));
+	size_t sizeof_sym_hist;
+
+	/* Check for overflow when calculating sizeof_sym_hist */
+	if (size > (SIZE_MAX - sizeof(struct sym_hist)) / sizeof(u64))
+		return -1;
+
+	sizeof_sym_hist = (sizeof(struct sym_hist) + size * sizeof(u64));
+
+	/* Check for overflow in zalloc argument */
+	if (sizeof_sym_hist > (SIZE_MAX - sizeof(*notes->src))
+				/ symbol_conf.nr_events)
+		return -1;
 
 	notes->src = zalloc(sizeof(*notes->src) + symbol_conf.nr_events * sizeof_sym_hist);
 	if (notes->src == NULL)