perf ordered_events: Prevent crossing max_alloc_size (53da12e0) · Commits · 戴 / test

Stephane reported a possible issue in the ordered events code, which could lead to allocating more memory than guarded by max_alloc_size. He also suggested the fix to properly check that the new size is below the max_alloc_size limit. Reported-by:

Stephane Eranian <eranian@google.com> Suggested-by:

Stephane Eranian <eranian@google.com> Signed-off-by:

Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20180907102455.7030-2-jolsa@kernel.org Signed-off-by:

Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/ordered-events.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -101,6 +101,7 @@ static struct ordered_event alloc_event(struct ordered_events oe,
		struct list_head *cache = &oe->cache;
		struct ordered_event *new = NULL;
		union perf_event *new_event;
		size_t size;

		new_event = dup_event(oe, event);
		if (!new_event)
		@@ -133,6 +134,8 @@ static struct ordered_event alloc_event(struct ordered_events oe,
		* Removal of ordered event object moves it from events to
		* the cache list.
		*/
		size = sizeof(oe->buffer) + MAX_SAMPLE_BUFFER sizeof(*new);

		if (!list_empty(cache)) {
		new = list_entry(cache->next, struct ordered_event, list);
		list_del(&new->list);
		@@ -140,10 +143,7 @@ static struct ordered_event alloc_event(struct ordered_events oe,
		new = &oe->buffer->event[oe->buffer_idx];
		if (++oe->buffer_idx == MAX_SAMPLE_BUFFER)
		oe->buffer = NULL;
		} else if (oe->cur_alloc_size < oe->max_alloc_size) {
		size_t size = sizeof(*oe->buffer) +
		MAX_SAMPLE_BUFFER * sizeof(*new);

		} else if ((oe->cur_alloc_size + size) < oe->max_alloc_size) {
		oe->buffer = malloc(size);
		if (!oe->buffer) {
		free_dup_event(oe, new_event);

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