7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bryam Vargas [ Upstream commit 97fc4b53dbe4a983fdf093243067fa6a64562307 ] cache_key_decode() takes a key's logical off from the cache device and later indexes req_key_tree->subtrees[] by it in get_subtree(). An off past the device forms a subtree pointer outside the array, which rb_insert() writes through during replay. Reject a key of zero length, or whose off+len (computed in 64 bits) exceeds the device size, before it is used. Fixes: 1d57628ff95b ("dm-pcache: add persistent cache target in device-mapper") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Signed-off-by: Mikulas Patocka Signed-off-by: Sasha Levin --- drivers/md/dm-pcache/cache_key.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/md/dm-pcache/cache_key.c b/drivers/md/dm-pcache/cache_key.c index 61a71876ca1d1..40afba5f3723b 100644 --- a/drivers/md/dm-pcache/cache_key.c +++ b/drivers/md/dm-pcache/cache_key.c @@ -90,10 +90,19 @@ int cache_key_decode(struct pcache_cache *cache, struct pcache_cache_key *key) { struct dm_pcache *pcache = CACHE_TO_PCACHE(cache); + u64 dev_bytes = (u64)cache->dev_size << SECTOR_SHIFT; key->off = key_onmedia->off; key->len = key_onmedia->len; + if (key_onmedia->len == 0 || + key_onmedia->len > dev_bytes || + key_onmedia->off > dev_bytes - key_onmedia->len) { + pcache_dev_err(pcache, "key off %llu + len %u exceeds device size\n", + key_onmedia->off, key_onmedia->len); + return -EIO; + } + if (!cache_seg_id_valid(cache, key_onmedia->cache_seg_id)) { pcache_dev_err(pcache, "invalid cache_seg_id %u in cache key (n_segs %u)\n", key_onmedia->cache_seg_id, cache->n_segs); -- 2.53.0