From: Eric Biggers ebiggers@google.com
[ Upstream commit 47a846536e1bf62626f1c0d8488f3718ce5f8296 ]
If there is only one keyslot, then blk_ksm_init() computes slot_hashtable_size=1 and log_slot_ht_size=0. This causes blk_ksm_find_keyslot() to crash later because it uses hash_ptr(key, log_slot_ht_size) to find the hash bucket containing the key, and hash_ptr() doesn't support the bits == 0 case.
Fix this by making the hash table always have at least 2 buckets.
Tested by running:
kvm-xfstests -c ext4 -g encrypt -m inlinecrypt \ -o blk-crypto-fallback.num_keyslots=1
Fixes: 1b2628397058 ("block: Keyslot Manager for Inline Encryption") Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/keyslot-manager.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/block/keyslot-manager.c b/block/keyslot-manager.c index 35abcb1ec051d..86f8195d8039e 100644 --- a/block/keyslot-manager.c +++ b/block/keyslot-manager.c @@ -103,6 +103,13 @@ int blk_ksm_init(struct blk_keyslot_manager *ksm, unsigned int num_slots) spin_lock_init(&ksm->idle_slots_lock);
slot_hashtable_size = roundup_pow_of_two(num_slots); + /* + * hash_ptr() assumes bits != 0, so ensure the hash table has at least 2 + * buckets. This only makes a difference when there is only 1 keyslot. + */ + if (slot_hashtable_size < 2) + slot_hashtable_size = 2; + ksm->log_slot_ht_size = ilog2(slot_hashtable_size); ksm->slot_hashtable = kvmalloc_array(slot_hashtable_size, sizeof(ksm->slot_hashtable[0]),