1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright 2019 Google LLC
4  */
5 
6 #ifndef __LINUX_BLK_CRYPTO_H
7 #define __LINUX_BLK_CRYPTO_H
8 
9 #include <linux/types.h>
10 
11 enum blk_crypto_mode_num {
12 	BLK_ENCRYPTION_MODE_INVALID,
13 	BLK_ENCRYPTION_MODE_AES_256_XTS,
14 	BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV,
15 	BLK_ENCRYPTION_MODE_ADIANTUM,
16 	BLK_ENCRYPTION_MODE_MAX,
17 };
18 
19 #define BLK_CRYPTO_MAX_KEY_SIZE		64
20 /**
21  * struct blk_crypto_config - an inline encryption key's crypto configuration
22  * @crypto_mode: encryption algorithm this key is for
23  * @data_unit_size: the data unit size for all encryption/decryptions with this
24  *	key.  This is the size in bytes of each individual plaintext and
25  *	ciphertext.  This is always a power of 2.  It might be e.g. the
26  *	filesystem block size or the disk sector size.
27  * @dun_bytes: the maximum number of bytes of DUN used when using this key
28  */
29 struct blk_crypto_config {
30 	enum blk_crypto_mode_num crypto_mode;
31 	unsigned int data_unit_size;
32 	unsigned int dun_bytes;
33 };
34 
35 /**
36  * struct blk_crypto_key - an inline encryption key
37  * @crypto_cfg: the crypto configuration (like crypto_mode, key size) for this
38  *		key
39  * @data_unit_size_bits: log2 of data_unit_size
40  * @size: size of this key in bytes (determined by @crypto_cfg.crypto_mode)
41  * @raw: the raw bytes of this key.  Only the first @size bytes are used.
42  *
43  * A blk_crypto_key is immutable once created, and many bios can reference it at
44  * the same time.  It must not be freed until all bios using it have completed
45  * and it has been evicted from all devices on which it may have been used.
46  */
47 struct blk_crypto_key {
48 	struct blk_crypto_config crypto_cfg;
49 	unsigned int data_unit_size_bits;
50 	unsigned int size;
51 	u8 raw[BLK_CRYPTO_MAX_KEY_SIZE];
52 };
53 
54 #define BLK_CRYPTO_MAX_IV_SIZE		32
55 #define BLK_CRYPTO_DUN_ARRAY_SIZE	(BLK_CRYPTO_MAX_IV_SIZE / sizeof(u64))
56 
57 /**
58  * struct bio_crypt_ctx - an inline encryption context
59  * @bc_key: the key, algorithm, and data unit size to use
60  * @bc_dun: the data unit number (starting IV) to use
61  *
62  * A bio_crypt_ctx specifies that the contents of the bio will be encrypted (for
63  * write requests) or decrypted (for read requests) inline by the storage device
64  * or controller, or by the crypto API fallback.
65  */
66 struct bio_crypt_ctx {
67 	const struct blk_crypto_key	*bc_key;
68 	u64				bc_dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
69 };
70 
71 #include <linux/blk_types.h>
72 #include <linux/blkdev.h>
73 
74 struct request;
75 struct request_queue;
76 
77 #ifdef CONFIG_BLK_INLINE_ENCRYPTION
78 
bio_has_crypt_ctx(struct bio * bio)79 static inline bool bio_has_crypt_ctx(struct bio *bio)
80 {
81 	return bio->bi_crypt_context;
82 }
83 
84 void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key,
85 		       const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
86 		       gfp_t gfp_mask);
87 
88 bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
89 				 unsigned int bytes,
90 				 const u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE]);
91 
92 int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key,
93 			enum blk_crypto_mode_num crypto_mode,
94 			unsigned int dun_bytes,
95 			unsigned int data_unit_size);
96 
97 int blk_crypto_start_using_key(const struct blk_crypto_key *key,
98 			       struct request_queue *q);
99 
100 int blk_crypto_evict_key(struct request_queue *q,
101 			 const struct blk_crypto_key *key);
102 
103 bool blk_crypto_config_supported(struct request_queue *q,
104 				 const struct blk_crypto_config *cfg);
105 
106 #else /* CONFIG_BLK_INLINE_ENCRYPTION */
107 
bio_has_crypt_ctx(struct bio * bio)108 static inline bool bio_has_crypt_ctx(struct bio *bio)
109 {
110 	return false;
111 }
112 
113 #endif /* CONFIG_BLK_INLINE_ENCRYPTION */
114 
115 int __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask);
116 /**
117  * bio_crypt_clone - clone bio encryption context
118  * @dst: destination bio
119  * @src: source bio
120  * @gfp_mask: memory allocation flags
121  *
122  * If @src has an encryption context, clone it to @dst.
123  *
124  * Return: 0 on success, -ENOMEM if out of memory.  -ENOMEM is only possible if
125  *	   @gfp_mask doesn't include %__GFP_DIRECT_RECLAIM.
126  */
bio_crypt_clone(struct bio * dst,struct bio * src,gfp_t gfp_mask)127 static inline int bio_crypt_clone(struct bio *dst, struct bio *src,
128 				  gfp_t gfp_mask)
129 {
130 	if (bio_has_crypt_ctx(src))
131 		return __bio_crypt_clone(dst, src, gfp_mask);
132 	return 0;
133 }
134 
135 #endif /* __LINUX_BLK_CRYPTO_H */
136