Commit 0b90dfda authored by Ian Rogers's avatar Ian Rogers Committed by Namhyung Kim
Browse files

perf maps: Fix use after free in __maps__fixup_overlap_and_insert 



In the case 'before' and 'after' are broken out from pos,
maps_by_address may be changed by __maps__insert, as such it needs
re-reading.

Don't ignore the return value from __maps_insert.

Fixes: 659ad349 ("perf maps: Switch from rbtree to lazily sorted array for addresses")
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Reviewed-by: default avatarJames Clark <james.clark@arm.com>
Cc: Steinar H . Gunderson <sesse@google.com>
Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240521165109.708593-2-irogers@google.com
parent a9700511

tools/perf/util/maps.c

+5 −4
Original line number Diff line number Diff line
@@ -741,7 +741,6 @@ static unsigned int first_ending_after(struct maps *maps, const struct map *map) 
 */

static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)

{

	struct map **maps_by_address;

	int err = 0;

	FILE *fp = debug_file();
@@ -749,12 +748,12 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) 
	if (!maps__maps_by_address_sorted(maps))

		__maps__sort_by_address(maps);



	maps_by_address = maps__maps_by_address(maps);

	/*

	 * Iterate through entries where the end of the existing entry is

	 * greater-than the new map's start.

	 */

	for (unsigned int i = first_ending_after(maps, new); i < maps__nr_maps(maps); ) {

		struct map **maps_by_address = maps__maps_by_address(maps);

		struct map *pos = maps_by_address[i];

		struct map *before = NULL, *after = NULL;
@@ -821,8 +820,10 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) 
			/* Maps are still ordered, go to next one. */

			i++;

			if (after) {

				__maps__insert(maps, after);

				err = __maps__insert(maps, after);

				map__put(after);

				if (err)

					goto out_err;

				if (!maps__maps_by_address_sorted(maps)) {

					/*

					 * Sorting broken so invariants don't
@@ -851,7 +852,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) 
		check_invariants(maps);

	}

	/* Add the map. */

	__maps__insert(maps, new);

	err = __maps__insert(maps, new);

out_err:

	return err;

}