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(src))
131 return __bio_crypt_clone(dst, src, gfp_mask);
132 return 0;
133 }
134
135 #endif /* __LINUX_BLK_CRYPTO_H */
136
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