diff options
| author | Ian Rogers <irogers@google.com> | 2025-11-18 21:05:54 -0800 |
|---|---|---|
| committer | Namhyung Kim <namhyung@kernel.org> | 2025-11-19 16:20:15 -0800 |
| commit | 245cfbcd3d3b298c75e01946262b3ff2cf7d0796 (patch) | |
| tree | 84ac43f58e16fa1c8f46cb366898211554bf5b88 /tools/perf/util | |
| parent | 51d87d977ec4efe000ac662ac924f00b9d8a23ec (diff) | |
perf maps: Avoid RC_CHK use after free
The case of __maps__fixup_overlap_and_insert where the "new" maps
covers existing mappings can create a use-after-free with reference
count checking enabled. The issue is that "pos" holds a map pointer
from maps_by_address that is put from maps_by_address but then used to
look for a map in maps_by_name (the compared map is now a
use-after-free). The issue stems from using maps__remove which redoes
some of the searches already done by __maps__fixup_overlap_and_insert,
so optimize the code (by avoiding repeated searches) and avoid the
use-after-free by inlining the appropriate removal code.
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202511141407.f9edcfa6-lkp@intel.com
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Diffstat (limited to 'tools/perf/util')
| -rw-r--r-- | tools/perf/util/maps.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c index 779f6230130a..c321d4f4d846 100644 --- a/tools/perf/util/maps.c +++ b/tools/perf/util/maps.c @@ -931,8 +931,9 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) return err; } else { struct map *next = NULL; + unsigned int nr_maps = maps__nr_maps(maps); - if (i + 1 < maps__nr_maps(maps)) + if (i + 1 < nr_maps) next = maps_by_address[i + 1]; if (!next || map__start(next) >= map__end(new)) { @@ -953,7 +954,24 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) check_invariants(maps); return err; } - __maps__remove(maps, pos); + /* + * pos fully covers the previous mapping so remove + * it. The following is an inlined version of + * maps__remove that reuses the already computed + * indices. + */ + map__put(maps_by_address[i]); + memmove(&maps_by_address[i], + &maps_by_address[i + 1], + (nr_maps - i - 1) * sizeof(*maps_by_address)); + + if (maps_by_name) { + map__put(maps_by_name[ni]); + memmove(&maps_by_name[ni], + &maps_by_name[ni + 1], + (nr_maps - ni - 1) * sizeof(*maps_by_name)); + } + --RC_CHK_ACCESS(maps)->nr_maps; check_invariants(maps); /* * Maps are ordered but no need to increase `i` as the |