include/linux/bio-crypt-ctx.h - kernel/common - Git at Google

 /* 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 */
	/* 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 */