LXR linux/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
  11enum 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 */
  29struct 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 */
  47struct 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 */
  66struct 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
  74struct request;
  75struct request_queue;
  76
  77#ifdef CONFIG_BLK_INLINE_ENCRYPTION
  78
  79static inline bool bio_has_crypt_ctx(struct bio *bio)
  80{
  81        return bio->bi_crypt_context;
  82}
  83
  84void 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
  88bool 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
  92int 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
  97int blk_crypto_start_using_key(const struct blk_crypto_key *key,
  98                               struct request_queue *q);
  99
 100int blk_crypto_evict_key(struct request_queue *q,
 101                         const struct blk_crypto_key *key);
 102
 103bool blk_crypto_config_supported(struct request_queue *q,
 104                                 const struct blk_crypto_config *cfg);
 105
 106#else /* CONFIG_BLK_INLINE_ENCRYPTION */
 107
 108static inline bool bio_has_crypt_ctx(struct bio *bio)
 109{
 110        return false;
 111}
 112
 113#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
 114
 115int __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 */
 127static 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