diff options
| author | Eric Biggers <ebiggers@google.com> | 2020-11-11 13:48:55 -0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-11-20 11:52:52 -0700 |
| commit | 47a846536e1bf62626f1c0d8488f3718ce5f8296 (patch) | |
| tree | a26fb9f3bd73eb3e521ec9fc76af8727629f7fe1 /block | |
| parent | 45f703a0d4b87f940ea150367dc4f4a9c06fa868 (diff) | |
block/keyslot-manager: prevent crash when num_slots=1
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>
Diffstat (limited to 'block')
| -rw-r--r-- | block/keyslot-manager.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/block/keyslot-manager.c b/block/keyslot-manager.c index 35abcb1ec051..86f8195d8039 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]), |