commit 5c7cb94452 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 70493a63ba upstream.
blk_crypto_evict_key() is only called in contexts such as inode eviction
where failure is not an option. So there is nothing the caller can do
with errors except log them. (dm-table.c does "use" the error code, but
only to pass on to upper layers, so it doesn't really count.)
Just make blk_crypto_evict_key() return void and log errors itself.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9cd1e56667 upstream.
Once all I/O using a blk_crypto_key has completed, filesystems can call
blk_crypto_evict_key(). However, the block layer currently doesn't call
blk_crypto_put_keyslot() until the request is being freed, which happens
after upper layers have been told (via bio_endio()) the I/O has
completed. This causes a race condition where blk_crypto_evict_key()
can see 'slot_refs != 0' without there being an actual bug.
This makes __blk_crypto_evict_key() hit the
'WARN_ON_ONCE(atomic_read(&slot->slot_refs) != 0)' and return without
doing anything, eventually causing a use-after-free in
blk_crypto_reprogram_all_keys(). (This is a very rare bug and has only
been seen when per-file keys are being used with fscrypt.)
There are two options to fix this: either release the keyslot before
bio_endio() is called on the request's last bio, or make
__blk_crypto_evict_key() ignore slot_refs. Let's go with the first
solution, since it preserves the ability to report bugs (via
WARN_ON_ONCE) where a key is evicted while still in-use.
Fixes: a892c8d52c ("block: Inline encryption support for blk-mq")
Cc: stable@vger.kernel.org
Reviewed-by: Nathan Huckleberry <nhuck@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20230315183907.53675-2-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
dun_bytes needs to be less than or equal to the IV size of the
encryption mode, not just less than or equal to BLK_CRYPTO_MAX_IV_SIZE.
Currently this doesn't matter since blk_crypto_init_key() is never
actually passed invalid values, but we might as well fix this.
Fixes: a892c8d52c ("block: Inline encryption support for blk-mq")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20210825055918.51975-1-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that device mapper supports inline encryption, add the ability to
evict keys from all underlying devices. When an upper layer requests
a key eviction, we simply iterate through all underlying devices
and evict that key from each device.
Co-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Replace the gendisk pointer in struct bio with a pointer to the newly
improved struct block device. From that the gendisk can be trivially
accessed with an extra indirection, but it also allows to directly
look up all information related to partition remapping.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bio_crypt_set_ctx() assumes its gfp_mask argument always includes
__GFP_DIRECT_RECLAIM, so that the mempool_alloc() will always succeed.
For now this assumption is still fine, since no callers violate it.
Making bio_crypt_set_ctx() able to fail would add unneeded complexity.
However, if a caller didn't use __GFP_DIRECT_RECLAIM, it would be very
hard to notice the bug. Make it easier by adding a WARN_ON_ONCE().
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Satya Tangirala <satyat@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Satya Tangirala <satyat@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_crypto_rq_bio_prep() assumes its gfp_mask argument always includes
__GFP_DIRECT_RECLAIM, so that the mempool_alloc() will always succeed.
However, blk_crypto_rq_bio_prep() might be called with GFP_ATOMIC via
setup_clone() in drivers/md/dm-rq.c.
This case isn't currently reachable with a bio that actually has an
encryption context. However, it's fragile to rely on this. Just make
blk_crypto_rq_bio_prep() able to fail.
Suggested-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Satya Tangirala <satyat@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bio_crypt_clone() assumes its gfp_mask argument always includes
__GFP_DIRECT_RECLAIM, so that the mempool_alloc() will always succeed.
However, bio_crypt_clone() might be called with GFP_ATOMIC via
setup_clone() in drivers/md/dm-rq.c, or with GFP_NOWAIT via
kcryptd_io_read() in drivers/md/dm-crypt.c.
Neither case is currently reachable with a bio that actually has an
encryption context. However, it's fragile to rely on this. Just make
bio_crypt_clone() able to fail, analogous to bio_integrity_clone().
Reported-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Satya Tangirala <satyat@google.com>
Cc: Satya Tangirala <satyat@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
generic_make_request has always been very confusingly misnamed, so rename
it to submit_bio_noacct to make it clear that it is submit_bio minus
accounting and a few checks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Blk-crypto delegates crypto operations to inline encryption hardware
when available. The separately configurable blk-crypto-fallback contains
a software fallback to the kernel crypto API - when enabled, blk-crypto
will use this fallback for en/decryption when inline encryption hardware
is not available.
This lets upper layers not have to worry about whether or not the
underlying device has support for inline encryption before deciding to
specify an encryption context for a bio. It also allows for testing
without actual inline encryption hardware - in particular, it makes it
possible to test the inline encryption code in ext4 and f2fs simply by
running xfstests with the inlinecrypt mount option, which in turn allows
for things like the regular upstream regression testing of ext4 to cover
the inline encryption code paths.
For more details, refer to Documentation/block/inline-encryption.rst.
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We must have some way of letting a storage device driver know what
encryption context it should use for en/decrypting a request. However,
it's the upper layers (like the filesystem/fscrypt) that know about and
manages encryption contexts. As such, when the upper layer submits a bio
to the block layer, and this bio eventually reaches a device driver with
support for inline encryption, the device driver will need to have been
told the encryption context for that bio.
We want to communicate the encryption context from the upper layer to the
storage device along with the bio, when the bio is submitted to the block
layer. To do this, we add a struct bio_crypt_ctx to struct bio, which can
represent an encryption context (note that we can't use the bi_private
field in struct bio to do this because that field does not function to pass
information across layers in the storage stack). We also introduce various
functions to manipulate the bio_crypt_ctx and make the bio/request merging
logic aware of the bio_crypt_ctx.
We also make changes to blk-mq to make it handle bios with encryption
contexts. blk-mq can merge many bios into the same request. These bios need
to have contiguous data unit numbers (the necessary changes to blk-merge
are also made to ensure this) - as such, it suffices to keep the data unit
number of just the first bio, since that's all a storage driver needs to
infer the data unit number to use for each data block in each bio in a
request. blk-mq keeps track of the encryption context to be used for all
the bios in a request with the request's rq_crypt_ctx. When the first bio
is added to an empty request, blk-mq will program the encryption context
of that bio into the request_queue's keyslot manager, and store the
returned keyslot in the request's rq_crypt_ctx. All the functions to
operate on encryption contexts are in blk-crypto.c.
Upper layers only need to call bio_crypt_set_ctx with the encryption key,
algorithm and data_unit_num; they don't have to worry about getting a
keyslot for each encryption context, as blk-mq/blk-crypto handles that.
Blk-crypto also makes it possible for request-based layered devices like
dm-rq to make use of inline encryption hardware by cloning the
rq_crypt_ctx and programming a keyslot in the new request_queue when
necessary.
Note that any user of the block layer can submit bios with an
encryption context, such as filesystems, device-mapper targets, etc.
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
