xref: /openbmc/linux/include/linux/blk-crypto.h (revision 70493a63)
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 
bio_has_crypt_ctx(struct bio * bio)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 
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