dm-verity.h 3.7 KB

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  1. /* SPDX-License-Identifier: GPL-2.0-only */
  2. /*
  3. * Copyright (C) 2012 Red Hat, Inc.
  4. * Copyright (C) 2015 Google, Inc.
  5. *
  6. * Author: Mikulas Patocka <mpatocka@redhat.com>
  7. *
  8. * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
  9. */
  10. #ifndef DM_VERITY_H
  11. #define DM_VERITY_H
  12. #include <linux/dm-bufio.h>
  13. #include <linux/device-mapper.h>
  14. #include <crypto/hash.h>
  15. #define DM_VERITY_MAX_LEVELS 63
  16. enum verity_mode {
  17. DM_VERITY_MODE_EIO,
  18. DM_VERITY_MODE_LOGGING,
  19. DM_VERITY_MODE_RESTART,
  20. DM_VERITY_MODE_PANIC
  21. };
  22. enum verity_block_type {
  23. DM_VERITY_BLOCK_TYPE_DATA,
  24. DM_VERITY_BLOCK_TYPE_METADATA
  25. };
  26. struct dm_verity_fec;
  27. struct dm_verity {
  28. struct dm_dev *data_dev;
  29. struct dm_dev *hash_dev;
  30. struct dm_target *ti;
  31. struct dm_bufio_client *bufio;
  32. char *alg_name;
  33. struct crypto_ahash *tfm;
  34. u8 *root_digest; /* digest of the root block */
  35. u8 *salt; /* salt: its size is salt_size */
  36. u8 *zero_digest; /* digest for a zero block */
  37. unsigned salt_size;
  38. sector_t data_start; /* data offset in 512-byte sectors */
  39. sector_t hash_start; /* hash start in blocks */
  40. sector_t data_blocks; /* the number of data blocks */
  41. sector_t hash_blocks; /* the number of hash blocks */
  42. unsigned char data_dev_block_bits; /* log2(data blocksize) */
  43. unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
  44. unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
  45. unsigned char levels; /* the number of tree levels */
  46. unsigned char version;
  47. unsigned digest_size; /* digest size for the current hash algorithm */
  48. unsigned int ahash_reqsize;/* the size of temporary space for crypto */
  49. int hash_failed; /* set to 1 if hash of any block failed */
  50. enum verity_mode mode; /* mode for handling verification errors */
  51. unsigned corrupted_errs;/* Number of errors for corrupted blocks */
  52. struct workqueue_struct *verify_wq;
  53. /* starting blocks for each tree level. 0 is the lowest level. */
  54. sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
  55. struct dm_verity_fec *fec; /* forward error correction */
  56. unsigned long *validated_blocks; /* bitset blocks validated */
  57. char *signature_key_desc; /* signature keyring reference */
  58. };
  59. struct dm_verity_io {
  60. struct dm_verity *v;
  61. /* original value of bio->bi_end_io */
  62. bio_end_io_t *orig_bi_end_io;
  63. sector_t block;
  64. unsigned n_blocks;
  65. struct bvec_iter iter;
  66. struct work_struct work;
  67. /*
  68. * Three variably-size fields follow this struct:
  69. *
  70. * u8 hash_req[v->ahash_reqsize];
  71. * u8 real_digest[v->digest_size];
  72. * u8 want_digest[v->digest_size];
  73. *
  74. * To access them use: verity_io_hash_req(), verity_io_real_digest()
  75. * and verity_io_want_digest().
  76. */
  77. };
  78. static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v,
  79. struct dm_verity_io *io)
  80. {
  81. return (struct ahash_request *)(io + 1);
  82. }
  83. static inline u8 *verity_io_real_digest(struct dm_verity *v,
  84. struct dm_verity_io *io)
  85. {
  86. return (u8 *)(io + 1) + v->ahash_reqsize;
  87. }
  88. static inline u8 *verity_io_want_digest(struct dm_verity *v,
  89. struct dm_verity_io *io)
  90. {
  91. return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size;
  92. }
  93. static inline u8 *verity_io_digest_end(struct dm_verity *v,
  94. struct dm_verity_io *io)
  95. {
  96. return verity_io_want_digest(v, io) + v->digest_size;
  97. }
  98. extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
  99. struct bvec_iter *iter,
  100. int (*process)(struct dm_verity *v,
  101. struct dm_verity_io *io,
  102. u8 *data, size_t len));
  103. extern int verity_hash(struct dm_verity *v, struct ahash_request *req,
  104. const u8 *data, size_t len, u8 *digest);
  105. extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
  106. sector_t block, u8 *digest, bool *is_zero);
  107. #endif /* DM_VERITY_H */