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2021-02-22Merge tag 'for-5.12/dm-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mike Snitzer: - Fix DM integrity's HMAC support to provide enhanced security of internal_hash and journal_mac capabilities. - Various DM writecache fixes to address performance, fix table output to match what was provided at table creation, fix writing beyond end of device when shrinking underlying data device, and a couple other small cleanups. - Add DM crypt support for using trusted keys. - Fix deadlock when swapping to DM crypt device by throttling number of in-flight REQ_SWAP bios. Implemented in DM core so that other bio-based targets can opt-in by setting ti->limit_swap_bios. - Fix various inverted logic bugs in the .iterate_devices callout functions that are used to assess if specific feature or capability is supported across all devices being combined/stacked by DM. - Fix DM era target bugs that exposed users to lost writes or memory leaks. - Add DM core support for passing through inline crypto support of underlying devices. Includes block/keyslot-manager changes that enable extending this support to DM. - Various small fixes and cleanups (spelling fixes, front padding calculation cleanup, cleanup conditional zoned support in targets, etc). * tag 'for-5.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (31 commits) dm: fix deadlock when swapping to encrypted device dm: simplify target code conditional on CONFIG_BLK_DEV_ZONED dm: set DM_TARGET_PASSES_CRYPTO feature for some targets dm: support key eviction from keyslot managers of underlying devices dm: add support for passing through inline crypto support block/keyslot-manager: Introduce functions for device mapper support block/keyslot-manager: Introduce passthrough keyslot manager dm era: only resize metadata in preresume dm era: Use correct value size in equality function of writeset tree dm era: Fix bitset memory leaks dm era: Verify the data block size hasn't changed dm era: Reinitialize bitset cache before digesting a new writeset dm era: Update in-core bitset after committing the metadata dm era: Recover committed writeset after crash dm writecache: use bdev_nr_sectors() instead of open-coded equivalent dm writecache: fix writing beyond end of underlying device when shrinking dm table: remove needless request_queue NULL pointer checks dm table: fix zoned iterate_devices based device capability checks dm table: fix DAX iterate_devices based device capability checks dm table: fix iterate_devices based device capability checks ...
2021-02-11block/keyslot-manager: Introduce functions for device mapper supportSatya Tangirala
Introduce blk_ksm_update_capabilities() to update the capabilities of a keyslot manager (ksm) in-place. The pointer to a ksm in a device's request queue may not be easily replaced, because upper layers like the filesystem might access it (e.g. for programming keys/checking capabilities) at the same time the device wants to replace that request queue's ksm (and free the old ksm's memory). This function allows the device to update the capabilities of the ksm in its request queue directly. Devices can safely update the ksm this way without any synchronization with upper layers *only* if the updated (new) ksm continues to support all the crypto capabilities that the old ksm did (see description below for blk_ksm_is_superset() for why this is so). Also introduce blk_ksm_is_superset() which checks whether one ksm's capabilities are a (not necessarily strict) superset of another ksm's. The blk-crypto framework requires that crypto capabilities that were advertised when a bio was created continue to be supported by the device until that bio is ended - in practice this probably means that a device's advertised crypto capabilities can *never* "shrink" (since there's no synchronization between bio creation and when a device may want to change its advertised capabilities) - so a previously advertised crypto capability must always continue to be supported. This function can be used to check that a new ksm is a valid replacement for an old ksm. Signed-off-by: Satya Tangirala <satyat@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Acked-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-02-11block/keyslot-manager: Introduce passthrough keyslot managerSatya Tangirala
The device mapper may map over devices that have inline encryption capabilities, and to make use of those capabilities, the DM device must itself advertise those inline encryption capabilities. One way to do this would be to have the DM device set up a keyslot manager with a "sufficiently large" number of keyslots, but that would use a lot of memory. Also, the DM device itself has no "keyslots", and it doesn't make much sense to talk about "programming a key into a DM device's keyslot manager", so all that extra memory used to represent those keyslots is just wasted. All a DM device really needs to be able to do is advertise the crypto capabilities of the underlying devices in a coherent manner and expose a way to evict keys from the underlying devices. There are also devices with inline encryption hardware that do not have a limited number of keyslots. One can send a raw encryption key along with a bio to these devices (as opposed to typical inline encryption hardware that require users to first program a raw encryption key into a keyslot, and send the index of that keyslot along with the bio). These devices also only need the same things from the keyslot manager that DM devices need - a way to advertise crypto capabilities and potentially a way to expose a function to evict keys from hardware. So we introduce a "passthrough" keyslot manager that provides a way to represent a keyslot manager that doesn't have just a limited number of keyslots, and for which do not require keys to be programmed into keyslots. DM devices can set up a passthrough keyslot manager in their request queues, and advertise appropriate crypto capabilities based on those of the underlying devices. Blk-crypto does not attempt to program keys into any keyslots in the passthrough keyslot manager. Instead, if/when the bio is resubmitted to the underlying device, blk-crypto will try to program the key into the underlying device's keyslot manager. Signed-off-by: Satya Tangirala <satyat@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Acked-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-02-01block/keyslot-manager: introduce devm_blk_ksm_init()Eric Biggers
Add a resource-managed variant of blk_ksm_init() so that drivers don't have to worry about calling blk_ksm_destroy(). Note that the implementation uses a custom devres action to call blk_ksm_destroy() rather than switching the two allocations to be directly devres-managed, e.g. with devm_kmalloc(). This is because we need to keep zeroing the memory containing the keyslots when it is freed, and also because we want to continue using kvmalloc() (and there is no devm_kvmalloc()). Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Satya Tangirala <satyat@google.com> Acked-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20210121082155.111333-2-ebiggers@kernel.org Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2020-11-20block/keyslot-manager: prevent crash when num_slots=1Eric Biggers
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>
2020-06-29block/keyslot-manager: use kvfree_sensitive()Eric Biggers
Make blk_ksm_destroy() use the kvfree_sensitive() function (which was introduced in v5.8-rc1) instead of open-coding it. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-14block: Make blk-integrity preclude hardware inline encryptionSatya Tangirala
Whenever a device supports blk-integrity, make the kernel pretend that the device doesn't support inline encryption (essentially by setting the keyslot manager in the request queue to NULL). There's no hardware currently that supports both integrity and inline encryption. However, it seems possible that there will be such hardware in the near future (like the NVMe key per I/O support that might support both inline encryption and PI). But properly integrating both features is not trivial, and without real hardware that implements both, it is difficult to tell if it will be done correctly by the majority of hardware that support both. So it seems best not to support both features together right now, and to decide what to do at probe time. 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>
2020-05-14block: Keyslot Manager for Inline EncryptionSatya Tangirala
Inline Encryption hardware allows software to specify an encryption context (an encryption key, crypto algorithm, data unit num, data unit size) along with a data transfer request to a storage device, and the inline encryption hardware will use that context to en/decrypt the data. The inline encryption hardware is part of the storage device, and it conceptually sits on the data path between system memory and the storage device. Inline Encryption hardware implementations often function around the concept of "keyslots". These implementations often have a limited number of "keyslots", each of which can hold a key (we say that a key can be "programmed" into a keyslot). Requests made to the storage device may have a keyslot and a data unit number associated with them, and the inline encryption hardware will en/decrypt the data in the requests using the key programmed into that associated keyslot and the data unit number specified with the request. As keyslots are limited, and programming keys may be expensive in many implementations, and multiple requests may use exactly the same encryption contexts, we introduce a Keyslot Manager to efficiently manage keyslots. We also introduce a blk_crypto_key, which will represent the key that's programmed into keyslots managed by keyslot managers. The keyslot manager also functions as the interface that upper layers will use to program keys into inline encryption hardware. For more information on the Keyslot Manager, refer to documentation found in block/keyslot-manager.c and linux/keyslot-manager.h. Co-developed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Eric Biggers <ebiggers@google.com> 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>