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_SM4_XTS, |
17 | BLK_ENCRYPTION_MODE_MAX, |
18 | }; |
19 | |
20 | #define BLK_CRYPTO_MAX_KEY_SIZE 64 |
21 | /** |
22 | * struct blk_crypto_config - an inline encryption key's crypto configuration |
23 | * @crypto_mode: encryption algorithm this key is for |
24 | * @data_unit_size: the data unit size for all encryption/decryptions with this |
25 | * key. This is the size in bytes of each individual plaintext and |
26 | * ciphertext. This is always a power of 2. It might be e.g. the |
27 | * filesystem block size or the disk sector size. |
28 | * @dun_bytes: the maximum number of bytes of DUN used when using this key |
29 | */ |
30 | struct blk_crypto_config { |
31 | enum blk_crypto_mode_num crypto_mode; |
32 | unsigned int data_unit_size; |
33 | unsigned int dun_bytes; |
34 | }; |
35 | |
36 | /** |
37 | * struct blk_crypto_key - an inline encryption key |
38 | * @crypto_cfg: the crypto configuration (like crypto_mode, key size) for this |
39 | * key |
40 | * @data_unit_size_bits: log2 of data_unit_size |
41 | * @size: size of this key in bytes (determined by @crypto_cfg.crypto_mode) |
42 | * @raw: the raw bytes of this key. Only the first @size bytes are used. |
43 | * |
44 | * A blk_crypto_key is immutable once created, and many bios can reference it at |
45 | * the same time. It must not be freed until all bios using it have completed |
46 | * and it has been evicted from all devices on which it may have been used. |
47 | */ |
48 | struct blk_crypto_key { |
49 | struct blk_crypto_config crypto_cfg; |
50 | unsigned int data_unit_size_bits; |
51 | unsigned int size; |
52 | u8 raw[BLK_CRYPTO_MAX_KEY_SIZE]; |
53 | }; |
54 | |
55 | #define BLK_CRYPTO_MAX_IV_SIZE 32 |
56 | #define BLK_CRYPTO_DUN_ARRAY_SIZE (BLK_CRYPTO_MAX_IV_SIZE / sizeof(u64)) |
57 | |
58 | /** |
59 | * struct bio_crypt_ctx - an inline encryption context |
60 | * @bc_key: the key, algorithm, and data unit size to use |
61 | * @bc_dun: the data unit number (starting IV) to use |
62 | * |
63 | * A bio_crypt_ctx specifies that the contents of the bio will be encrypted (for |
64 | * write requests) or decrypted (for read requests) inline by the storage device |
65 | * or controller, or by the crypto API fallback. |
66 | */ |
67 | struct bio_crypt_ctx { |
68 | const struct blk_crypto_key *bc_key; |
69 | u64 bc_dun[BLK_CRYPTO_DUN_ARRAY_SIZE]; |
70 | }; |
71 | |
72 | #include <linux/blk_types.h> |
73 | #include <linux/blkdev.h> |
74 | |
75 | #ifdef CONFIG_BLK_INLINE_ENCRYPTION |
76 | |
77 | static inline bool bio_has_crypt_ctx(struct bio *bio) |
78 | { |
79 | return bio->bi_crypt_context; |
80 | } |
81 | |
82 | void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key, |
83 | const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE], |
84 | gfp_t gfp_mask); |
85 | |
86 | bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc, |
87 | unsigned int bytes, |
88 | const u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE]); |
89 | |
90 | int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key, |
91 | enum blk_crypto_mode_num crypto_mode, |
92 | unsigned int dun_bytes, |
93 | unsigned int data_unit_size); |
94 | |
95 | int blk_crypto_start_using_key(struct block_device *bdev, |
96 | const struct blk_crypto_key *key); |
97 | |
98 | void blk_crypto_evict_key(struct block_device *bdev, |
99 | const struct blk_crypto_key *key); |
100 | |
101 | bool blk_crypto_config_supported_natively(struct block_device *bdev, |
102 | const struct blk_crypto_config *cfg); |
103 | bool blk_crypto_config_supported(struct block_device *bdev, |
104 | const struct blk_crypto_config *cfg); |
105 | |
106 | #else /* CONFIG_BLK_INLINE_ENCRYPTION */ |
107 | |
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 | */ |
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(bio: src)) |
131 | return __bio_crypt_clone(dst, src, gfp_mask); |
132 | return 0; |
133 | } |
134 | |
135 | #endif /* __LINUX_BLK_CRYPTO_H */ |
136 | |