include/linux/blk-crypto.h

   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
  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
 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 */