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 #define BLK_CRYPTO_MAX_WRAPPED_KEY_SIZE 128
21
22 /**
23 * struct blk_crypto_config - an inline encryption key's crypto configuration
24 * @crypto_mode: encryption algorithm this key is for
25 * @data_unit_size: the data unit size for all encryption/decryptions with this
26 * key. This is the size in bytes of each individual plaintext and
27 * ciphertext. This is always a power of 2. It might be e.g. the
28 * filesystem block size or the disk sector size.
29 * @dun_bytes: the maximum number of bytes of DUN used when using this key
30 * @is_hw_wrapped: @raw points to a wrapped key to be used by an inline
31 * encryption hardware that accepts wrapped keys.
32 */
33 struct blk_crypto_config {
34 enum blk_crypto_mode_num crypto_mode;
35 unsigned int data_unit_size;
36 unsigned int dun_bytes;
37 bool is_hw_wrapped;
38 };
39
40 /**
41 * struct blk_crypto_key - an inline encryption key
42 * @crypto_cfg: the crypto configuration (like crypto_mode, key size) for this
43 * key
44 * @data_unit_size_bits: log2 of data_unit_size
45 * @size: size of this key in bytes (determined by @crypto_cfg.crypto_mode)
46 * @raw: the raw bytes of this key. Only the first @size bytes are used.
47 *
48 * A blk_crypto_key is immutable once created, and many bios can reference it at
49 * the same time. It must not be freed until all bios using it have completed
50 * and it has been evicted from all devices on which it may have been used.
51 */
52 struct blk_crypto_key {
53 struct blk_crypto_config crypto_cfg;
54 unsigned int data_unit_size_bits;
55 unsigned int size;
56 u8 raw[BLK_CRYPTO_MAX_WRAPPED_KEY_SIZE];
57 };
58
59 #define BLK_CRYPTO_MAX_IV_SIZE 32
60 #define BLK_CRYPTO_DUN_ARRAY_SIZE (BLK_CRYPTO_MAX_IV_SIZE / sizeof(u64))
61
62 /**
63 * struct bio_crypt_ctx - an inline encryption context
64 * @bc_key: the key, algorithm, and data unit size to use
65 * @bc_dun: the data unit number (starting IV) to use
66 *
67 * A bio_crypt_ctx specifies that the contents of the bio will be encrypted (for
68 * write requests) or decrypted (for read requests) inline by the storage device
69 * or controller, or by the crypto API fallback.
70 */
71 struct bio_crypt_ctx {
72 const struct blk_crypto_key *bc_key;
73 u64 bc_dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
74 };
75
76 #include <linux/blk_types.h>
77 #include <linux/blkdev.h>
78
79 struct request;
80 struct request_queue;
81
82 #ifdef CONFIG_BLK_INLINE_ENCRYPTION
83
bio_has_crypt_ctx(struct bio * bio)84 static inline bool bio_has_crypt_ctx(struct bio *bio)
85 {
86 return bio->bi_crypt_context;
87 }
88
89 void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key,
90 const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
91 gfp_t gfp_mask);
92
93 bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
94 unsigned int bytes,
95 const u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE]);
96
97 int blk_crypto_init_key(struct blk_crypto_key *blk_key,
98 const u8 *raw_key, unsigned int raw_key_size,
99 bool is_hw_wrapped,
100 enum blk_crypto_mode_num crypto_mode,
101 unsigned int dun_bytes,
102 unsigned int data_unit_size);
103
104 int blk_crypto_start_using_key(const struct blk_crypto_key *key,
105 struct request_queue *q);
106
107 void blk_crypto_evict_key(struct request_queue *q,
108 const struct blk_crypto_key *key);
109
110 bool blk_crypto_config_supported(struct request_queue *q,
111 const struct blk_crypto_config *cfg);
112
113 #else /* CONFIG_BLK_INLINE_ENCRYPTION */
114
bio_has_crypt_ctx(struct bio * bio)115 static inline bool bio_has_crypt_ctx(struct bio *bio)
116 {
117 return false;
118 }
119
120 #endif /* CONFIG_BLK_INLINE_ENCRYPTION */
121
122 static inline void bio_clone_skip_dm_default_key(struct bio *dst,
123 const struct bio *src);
124
125 int __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask);
126 /**
127 * bio_crypt_clone - clone bio encryption context
128 * @dst: destination bio
129 * @src: source bio
130 * @gfp_mask: memory allocation flags
131 *
132 * If @src has an encryption context, clone it to @dst.
133 *
134 * Return: 0 on success, -ENOMEM if out of memory. -ENOMEM is only possible if
135 * @gfp_mask doesn't include %__GFP_DIRECT_RECLAIM.
136 */
bio_crypt_clone(struct bio * dst,struct bio * src,gfp_t gfp_mask)137 static inline int bio_crypt_clone(struct bio *dst, struct bio *src,
138 gfp_t gfp_mask)
139 {
140 bio_clone_skip_dm_default_key(dst, src);
141 if (bio_has_crypt_ctx(src))
142 return __bio_crypt_clone(dst, src, gfp_mask);
143 return 0;
144 }
145
146 #if IS_ENABLED(CONFIG_DM_DEFAULT_KEY)
bio_set_skip_dm_default_key(struct bio * bio)147 static inline void bio_set_skip_dm_default_key(struct bio *bio)
148 {
149 bio->bi_skip_dm_default_key = true;
150 }
151
bio_should_skip_dm_default_key(const struct bio * bio)152 static inline bool bio_should_skip_dm_default_key(const struct bio *bio)
153 {
154 return bio->bi_skip_dm_default_key;
155 }
156
bio_clone_skip_dm_default_key(struct bio * dst,const struct bio * src)157 static inline void bio_clone_skip_dm_default_key(struct bio *dst,
158 const struct bio *src)
159 {
160 dst->bi_skip_dm_default_key = src->bi_skip_dm_default_key;
161 }
162 #else /* CONFIG_DM_DEFAULT_KEY */
bio_set_skip_dm_default_key(struct bio * bio)163 static inline void bio_set_skip_dm_default_key(struct bio *bio)
164 {
165 }
166
bio_should_skip_dm_default_key(const struct bio * bio)167 static inline bool bio_should_skip_dm_default_key(const struct bio *bio)
168 {
169 return false;
170 }
171
bio_clone_skip_dm_default_key(struct bio * dst,const struct bio * src)172 static inline void bio_clone_skip_dm_default_key(struct bio *dst,
173 const struct bio *src)
174 {
175 }
176 #endif /* !CONFIG_DM_DEFAULT_KEY */
177
178 #endif /* __LINUX_BLK_CRYPTO_H */
179