Files
linux/block
Eric Biggers 9fe0c97d45 FROMGIT: blk-crypto: make blk_crypto_evict_key() more robust
If blk_crypto_evict_key() sees that the key is still in-use (due to a
bug) or that ->keyslot_evict failed, it currently just returns while
leaving the key linked into the keyslot management structures.

However, blk_crypto_evict_key() is only called in contexts such as inode
eviction where failure is not an option.  So actually the caller
proceeds with freeing the blk_crypto_key regardless of the return value
of blk_crypto_evict_key().

These two assumptions don't match, and the result is that there can be a
use-after-free in blk_crypto_reprogram_all_keys() after one of these
errors occurs.  (Note, these errors *shouldn't* happen; we're just
talking about what happens if they do anyway.)

Fix this by making blk_crypto_evict_key() unlink the key from the
keyslot management structures even on failure.

Also improve some comments.

Fixes: 1b26283970 ("block: Keyslot Manager for Inline Encryption")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230315183907.53675-2-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Bug: 270098322
(cherry picked from commit 5c7cb94452
 https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/log/?h=for-next)
Change-Id: I4e8983ad7db94ea8cd422743196da8854adda552
Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-03-29 20:05:28 +00:00
..
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