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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright 2019 Google LLC
*/
#ifndef __LINUX_BLK_CRYPTO_H
#define __LINUX_BLK_CRYPTO_H
#include <linux/types.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_SM4_XTS,
BLK_ENCRYPTION_MODE_MAX,
};
#define BLK_CRYPTO_MAX_KEY_SIZE 64
/**
* struct blk_crypto_config - an inline encryption key's crypto configuration
* @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.
* @dun_bytes: the maximum number of bytes of DUN used when using this key
*/
struct blk_crypto_config {
enum blk_crypto_mode_num crypto_mode;
unsigned int data_unit_size;
unsigned int dun_bytes;
};
/**
* struct blk_crypto_key - an inline encryption key
* @crypto_cfg: the crypto configuration (like crypto_mode, key size) for this
* key
* @data_unit_size_bits: log2 of data_unit_size
* @size: size of this key in bytes (determined by @crypto_cfg.crypto_mode)
* @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
* and it has been evicted from all devices on which it may have been used.
*/
struct blk_crypto_key {
struct blk_crypto_config crypto_cfg;
unsigned int data_unit_size_bits;
unsigned int size;
u8 raw[BLK_CRYPTO_MAX_KEY_SIZE];
};
#define BLK_CRYPTO_MAX_IV_SIZE 32
#define BLK_CRYPTO_DUN_ARRAY_SIZE (BLK_CRYPTO_MAX_IV_SIZE / sizeof(u64))
/**
* struct bio_crypt_ctx - an inline encryption context
* @bc_key: the key, algorithm, and data unit size to use
* @bc_dun: the data unit number (starting IV) to use
*
* 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;
u64 bc_dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
};
#include <linux/blk_types.h>
#include <linux/blkdev.h>
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
static inline bool bio_has_crypt_ctx(struct bio *bio)
{
return bio->bi_crypt_context;
}
void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key,
const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
gfp_t gfp_mask);
bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
unsigned int bytes,
const u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE]);
int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key,
enum blk_crypto_mode_num crypto_mode,
unsigned int dun_bytes,
unsigned int data_unit_size);
int blk_crypto_start_using_key(struct block_device *bdev,
const struct blk_crypto_key *key);
void blk_crypto_evict_key(struct block_device *bdev,
const struct blk_crypto_key *key);
bool blk_crypto_config_supported_natively(struct block_device *bdev,
const struct blk_crypto_config *cfg);
bool blk_crypto_config_supported(struct block_device *bdev,
const struct blk_crypto_config *cfg);
#else /* CONFIG_BLK_INLINE_ENCRYPTION */
static inline bool bio_has_crypt_ctx(struct bio *bio)
{
return false;
}
#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
int __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask);
/**
* bio_crypt_clone - clone bio encryption context
* @dst: destination bio
* @src: source bio
* @gfp_mask: memory allocation flags
*
* If @src has an encryption context, clone it to @dst.
*
* Return: 0 on success, -ENOMEM if out of memory. -ENOMEM is only possible if
* @gfp_mask doesn't include %__GFP_DIRECT_RECLAIM.
*/
static inline int bio_crypt_clone(struct bio *dst, struct bio *src,
gfp_t gfp_mask)
{
if (bio_has_crypt_ctx(src))
return __bio_crypt_clone(dst, src, gfp_mask);
return 0;
}
#endif /* __LINUX_BLK_CRYPTO_H */
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