/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright 2019 Google LLC
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*/
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#ifndef __LINUX_BIO_CRYPT_CTX_H
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#define __LINUX_BIO_CRYPT_CTX_H
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enum blk_crypto_mode_num {
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BLK_ENCRYPTION_MODE_INVALID,
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BLK_ENCRYPTION_MODE_AES_256_XTS,
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BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV,
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BLK_ENCRYPTION_MODE_ADIANTUM,
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BLK_ENCRYPTION_MODE_MAX,
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};
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#ifdef CONFIG_BLOCK
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#include <linux/blk_types.h>
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#ifdef CONFIG_BLK_INLINE_ENCRYPTION
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#define BLK_CRYPTO_MAX_KEY_SIZE 64
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#define BLK_CRYPTO_MAX_WRAPPED_KEY_SIZE 128
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/**
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* struct blk_crypto_key - an inline encryption key
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* @crypto_mode: encryption algorithm this key is for
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* @data_unit_size: the data unit size for all encryption/decryptions with this
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* key. This is the size in bytes of each individual plaintext and
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* ciphertext. This is always a power of 2. It might be e.g. the
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* filesystem block size or the disk sector size.
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* @data_unit_size_bits: log2 of data_unit_size
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* @size: size of this key in bytes (determined by @crypto_mode)
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* @hash: hash of this key, for keyslot manager use only
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* @is_hw_wrapped: @raw points to a wrapped key to be used by an inline
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* encryption hardware that accepts wrapped keys.
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* @raw: the raw bytes of this key. Only the first @size bytes are used.
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*
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* A blk_crypto_key is immutable once created, and many bios can reference it at
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* the same time. It must not be freed until all bios using it have completed.
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*/
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struct blk_crypto_key {
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enum blk_crypto_mode_num crypto_mode;
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unsigned int data_unit_size;
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unsigned int data_unit_size_bits;
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unsigned int size;
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/*
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* Hack to avoid breaking KMI: pack both hash and dun_bytes into the
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* hash field...
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*/
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#define BLK_CRYPTO_KEY_HASH_MASK 0xffffff
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#define BLK_CRYPTO_KEY_DUN_BYTES_SHIFT 24
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unsigned int hash;
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bool is_hw_wrapped;
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u8 raw[BLK_CRYPTO_MAX_WRAPPED_KEY_SIZE];
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};
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#define BLK_CRYPTO_MAX_IV_SIZE 32
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#define BLK_CRYPTO_DUN_ARRAY_SIZE (BLK_CRYPTO_MAX_IV_SIZE/sizeof(u64))
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static inline void
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blk_crypto_key_set_hash_and_dun_bytes(struct blk_crypto_key *key,
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u32 hash, unsigned int dun_bytes)
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{
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key->hash = (dun_bytes << BLK_CRYPTO_KEY_DUN_BYTES_SHIFT) |
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(hash & BLK_CRYPTO_KEY_HASH_MASK);
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}
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static inline u32
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blk_crypto_key_hash(const struct blk_crypto_key *key)
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{
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return key->hash & BLK_CRYPTO_KEY_HASH_MASK;
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}
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static inline unsigned int
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blk_crypto_key_dun_bytes(const struct blk_crypto_key *key)
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{
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return key->hash >> BLK_CRYPTO_KEY_DUN_BYTES_SHIFT;
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}
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/**
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* struct bio_crypt_ctx - an inline encryption context
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* @bc_key: the key, algorithm, and data unit size to use
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* @bc_keyslot: the keyslot that has been assigned for this key in @bc_ksm,
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* or -1 if no keyslot has been assigned yet.
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* @bc_dun: the data unit number (starting IV) to use
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* @bc_ksm: the keyslot manager into which the key has been programmed with
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* @bc_keyslot, or NULL if this key hasn't yet been programmed.
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*
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* A bio_crypt_ctx specifies that the contents of the bio will be encrypted (for
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* write requests) or decrypted (for read requests) inline by the storage device
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* or controller, or by the crypto API fallback.
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*/
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struct bio_crypt_ctx {
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const struct blk_crypto_key *bc_key;
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int bc_keyslot;
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/* Data unit number */
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u64 bc_dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
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/*
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* The keyslot manager where the key has been programmed
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* with keyslot.
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*/
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struct keyslot_manager *bc_ksm;
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};
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int bio_crypt_ctx_init(void);
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struct bio_crypt_ctx *bio_crypt_alloc_ctx(gfp_t gfp_mask);
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void bio_crypt_free_ctx(struct bio *bio);
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static inline bool bio_has_crypt_ctx(struct bio *bio)
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{
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return bio->bi_crypt_context;
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}
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void bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask);
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static inline void bio_crypt_set_ctx(struct bio *bio,
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const struct blk_crypto_key *key,
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u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
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gfp_t gfp_mask)
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{
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struct bio_crypt_ctx *bc = bio_crypt_alloc_ctx(gfp_mask);
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bc->bc_key = key;
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memcpy(bc->bc_dun, dun, sizeof(bc->bc_dun));
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bc->bc_ksm = NULL;
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bc->bc_keyslot = -1;
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bio->bi_crypt_context = bc;
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}
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void bio_crypt_ctx_release_keyslot(struct bio_crypt_ctx *bc);
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int bio_crypt_ctx_acquire_keyslot(struct bio_crypt_ctx *bc,
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struct keyslot_manager *ksm);
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struct request;
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bool bio_crypt_should_process(struct request *rq);
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static inline bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
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unsigned int bytes,
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u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE])
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{
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int i = 0;
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unsigned int inc = bytes >> bc->bc_key->data_unit_size_bits;
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while (i < BLK_CRYPTO_DUN_ARRAY_SIZE) {
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if (bc->bc_dun[i] + inc != next_dun[i])
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return false;
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inc = ((bc->bc_dun[i] + inc) < inc);
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i++;
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}
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return true;
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}
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static inline void bio_crypt_dun_increment(u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
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unsigned int inc)
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{
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int i = 0;
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while (inc && i < BLK_CRYPTO_DUN_ARRAY_SIZE) {
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dun[i] += inc;
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inc = (dun[i] < inc);
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i++;
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}
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}
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static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes)
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{
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struct bio_crypt_ctx *bc = bio->bi_crypt_context;
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if (!bc)
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return;
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bio_crypt_dun_increment(bc->bc_dun,
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bytes >> bc->bc_key->data_unit_size_bits);
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}
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bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2);
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bool bio_crypt_ctx_mergeable(struct bio *b_1, unsigned int b1_bytes,
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struct bio *b_2);
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#else /* CONFIG_BLK_INLINE_ENCRYPTION */
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static inline int bio_crypt_ctx_init(void)
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{
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return 0;
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}
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static inline bool bio_has_crypt_ctx(struct bio *bio)
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{
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return false;
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}
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static inline void bio_crypt_clone(struct bio *dst, struct bio *src,
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gfp_t gfp_mask) { }
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static inline void bio_crypt_free_ctx(struct bio *bio) { }
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static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes) { }
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static inline bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2)
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{
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return true;
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}
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static inline bool bio_crypt_ctx_mergeable(struct bio *b_1,
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unsigned int b1_bytes,
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struct bio *b_2)
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{
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return true;
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}
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#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
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#if IS_ENABLED(CONFIG_DM_DEFAULT_KEY)
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static inline void bio_set_skip_dm_default_key(struct bio *bio)
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{
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bio->bi_skip_dm_default_key = true;
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}
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static inline bool bio_should_skip_dm_default_key(const struct bio *bio)
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{
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return bio->bi_skip_dm_default_key;
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}
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static inline void bio_clone_skip_dm_default_key(struct bio *dst,
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const struct bio *src)
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{
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dst->bi_skip_dm_default_key = src->bi_skip_dm_default_key;
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}
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#else /* CONFIG_DM_DEFAULT_KEY */
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static inline void bio_set_skip_dm_default_key(struct bio *bio)
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{
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}
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static inline bool bio_should_skip_dm_default_key(const struct bio *bio)
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{
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return false;
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}
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static inline void bio_clone_skip_dm_default_key(struct bio *dst,
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const struct bio *src)
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{
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}
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#endif /* !CONFIG_DM_DEFAULT_KEY */
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#endif /* CONFIG_BLOCK */
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#endif /* __LINUX_BIO_CRYPT_CTX_H */
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