blob: 9df113f74e9e3af884c6dfcf6d864982b543d3e4 [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright 2019 Google LLC
*/
#ifndef __LINUX_BIO_CRYPT_CTX_H
#define __LINUX_BIO_CRYPT_CTX_H
enum blk_crypto_mode_num {
BLK_ENCRYPTION_MODE_INVALID,
BLK_ENCRYPTION_MODE_AES_256_XTS,
BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV,
BLK_ENCRYPTION_MODE_ADIANTUM,
BLK_ENCRYPTION_MODE_MAX,
};
#ifdef CONFIG_BLOCK
#include <linux/blk_types.h>
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
#define BLK_CRYPTO_MAX_KEY_SIZE 64
#define BLK_CRYPTO_MAX_WRAPPED_KEY_SIZE 128
/**
* struct blk_crypto_key - an inline encryption key
* @crypto_mode: encryption algorithm this key is for
* @data_unit_size: the data unit size for all encryption/decryptions with this
* key. This is the size in bytes of each individual plaintext and
* ciphertext. This is always a power of 2. It might be e.g. the
* filesystem block size or the disk sector size.
* @data_unit_size_bits: log2 of data_unit_size
* @size: size of this key in bytes (determined by @crypto_mode)
* @hash: hash of this key, for keyslot manager use only
* @is_hw_wrapped: @raw points to a wrapped key to be used by an inline
* encryption hardware that accepts wrapped keys.
* @raw: the raw bytes of this key. Only the first @size bytes are used.
*
* A blk_crypto_key is immutable once created, and many bios can reference it at
* the same time. It must not be freed until all bios using it have completed.
*/
struct blk_crypto_key {
enum blk_crypto_mode_num crypto_mode;
unsigned int data_unit_size;
unsigned int data_unit_size_bits;
unsigned int size;
/*
* Hack to avoid breaking KMI: pack both hash and dun_bytes into the
* hash field...
*/
#define BLK_CRYPTO_KEY_HASH_MASK 0xffffff
#define BLK_CRYPTO_KEY_DUN_BYTES_SHIFT 24
unsigned int hash;
bool is_hw_wrapped;
u8 raw[BLK_CRYPTO_MAX_WRAPPED_KEY_SIZE];
};
#define BLK_CRYPTO_MAX_IV_SIZE 32
#define BLK_CRYPTO_DUN_ARRAY_SIZE (BLK_CRYPTO_MAX_IV_SIZE/sizeof(u64))
static inline void
blk_crypto_key_set_hash_and_dun_bytes(struct blk_crypto_key *key,
u32 hash, unsigned int dun_bytes)
{
key->hash = (dun_bytes << BLK_CRYPTO_KEY_DUN_BYTES_SHIFT) |
(hash & BLK_CRYPTO_KEY_HASH_MASK);
}
static inline u32
blk_crypto_key_hash(const struct blk_crypto_key *key)
{
return key->hash & BLK_CRYPTO_KEY_HASH_MASK;
}
static inline unsigned int
blk_crypto_key_dun_bytes(const struct blk_crypto_key *key)
{
return key->hash >> BLK_CRYPTO_KEY_DUN_BYTES_SHIFT;
}
/**
* struct bio_crypt_ctx - an inline encryption context
* @bc_key: the key, algorithm, and data unit size to use
* @bc_keyslot: the keyslot that has been assigned for this key in @bc_ksm,
* or -1 if no keyslot has been assigned yet.
* @bc_dun: the data unit number (starting IV) to use
* @bc_ksm: the keyslot manager into which the key has been programmed with
* @bc_keyslot, or NULL if this key hasn't yet been programmed.
*
* A bio_crypt_ctx specifies that the contents of the bio will be encrypted (for
* write requests) or decrypted (for read requests) inline by the storage device
* or controller, or by the crypto API fallback.
*/
struct bio_crypt_ctx {
const struct blk_crypto_key *bc_key;
int bc_keyslot;
/* Data unit number */
u64 bc_dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
/*
* The keyslot manager where the key has been programmed
* with keyslot.
*/
struct keyslot_manager *bc_ksm;
};
int bio_crypt_ctx_init(void);
struct bio_crypt_ctx *bio_crypt_alloc_ctx(gfp_t gfp_mask);
void bio_crypt_free_ctx(struct bio *bio);
static inline bool bio_has_crypt_ctx(struct bio *bio)
{
return bio->bi_crypt_context;
}
void bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask);
static inline void bio_crypt_set_ctx(struct bio *bio,
const struct blk_crypto_key *key,
u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
gfp_t gfp_mask)
{
struct bio_crypt_ctx *bc = bio_crypt_alloc_ctx(gfp_mask);
bc->bc_key = key;
memcpy(bc->bc_dun, dun, sizeof(bc->bc_dun));
bc->bc_ksm = NULL;
bc->bc_keyslot = -1;
bio->bi_crypt_context = bc;
}
void bio_crypt_ctx_release_keyslot(struct bio_crypt_ctx *bc);
int bio_crypt_ctx_acquire_keyslot(struct bio_crypt_ctx *bc,
struct keyslot_manager *ksm);
struct request;
bool bio_crypt_should_process(struct request *rq);
static inline bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
unsigned int bytes,
u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE])
{
int i = 0;
unsigned int inc = bytes >> bc->bc_key->data_unit_size_bits;
while (i < BLK_CRYPTO_DUN_ARRAY_SIZE) {
if (bc->bc_dun[i] + inc != next_dun[i])
return false;
inc = ((bc->bc_dun[i] + inc) < inc);
i++;
}
return true;
}
static inline void bio_crypt_dun_increment(u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
unsigned int inc)
{
int i = 0;
while (inc && i < BLK_CRYPTO_DUN_ARRAY_SIZE) {
dun[i] += inc;
inc = (dun[i] < inc);
i++;
}
}
static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes)
{
struct bio_crypt_ctx *bc = bio->bi_crypt_context;
if (!bc)
return;
bio_crypt_dun_increment(bc->bc_dun,
bytes >> bc->bc_key->data_unit_size_bits);
}
bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2);
bool bio_crypt_ctx_mergeable(struct bio *b_1, unsigned int b1_bytes,
struct bio *b_2);
#else /* CONFIG_BLK_INLINE_ENCRYPTION */
static inline int bio_crypt_ctx_init(void)
{
return 0;
}
static inline bool bio_has_crypt_ctx(struct bio *bio)
{
return false;
}
static inline void bio_crypt_clone(struct bio *dst, struct bio *src,
gfp_t gfp_mask) { }
static inline void bio_crypt_free_ctx(struct bio *bio) { }
static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes) { }
static inline bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2)
{
return true;
}
static inline bool bio_crypt_ctx_mergeable(struct bio *b_1,
unsigned int b1_bytes,
struct bio *b_2)
{
return true;
}
#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
#if IS_ENABLED(CONFIG_DM_DEFAULT_KEY)
static inline void bio_set_skip_dm_default_key(struct bio *bio)
{
bio->bi_skip_dm_default_key = true;
}
static inline bool bio_should_skip_dm_default_key(const struct bio *bio)
{
return bio->bi_skip_dm_default_key;
}
static inline void bio_clone_skip_dm_default_key(struct bio *dst,
const struct bio *src)
{
dst->bi_skip_dm_default_key = src->bi_skip_dm_default_key;
}
#else /* CONFIG_DM_DEFAULT_KEY */
static inline void bio_set_skip_dm_default_key(struct bio *bio)
{
}
static inline bool bio_should_skip_dm_default_key(const struct bio *bio)
{
return false;
}
static inline void bio_clone_skip_dm_default_key(struct bio *dst,
const struct bio *src)
{
}
#endif /* !CONFIG_DM_DEFAULT_KEY */
#endif /* CONFIG_BLOCK */
#endif /* __LINUX_BIO_CRYPT_CTX_H */