drivers/md/dm-verity.h

   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
  11 #ifndef DM_VERITY_H
  12 #define DM_VERITY_H
  13
  14 #include <linux/dm-io.h>
  15 #include <linux/dm-bufio.h>
  16 #include <linux/device-mapper.h>
  17 #include <linux/interrupt.h>
  18 #include <crypto/hash.h>
  19
  20 #define DM_VERITY_MAX_LEVELS            63
  21
  22 enum verity_mode {
  23         DM_VERITY_MODE_EIO,
  24         DM_VERITY_MODE_LOGGING,
  25         DM_VERITY_MODE_RESTART,
  26         DM_VERITY_MODE_PANIC
  27 };
  28
  29 enum verity_block_type {
  30         DM_VERITY_BLOCK_TYPE_DATA,
  31         DM_VERITY_BLOCK_TYPE_METADATA
  32 };
  33
  34 struct dm_verity_fec;
  35
  36 struct dm_verity {
  37         struct dm_dev *data_dev;
  38         struct dm_dev *hash_dev;
  39         struct dm_target *ti;
  40         struct dm_bufio_client *bufio;
  41         char *alg_name;
  42         struct crypto_ahash *ahash_tfm; /* either this or shash_tfm is set */
  43         struct crypto_shash *shash_tfm; /* either this or ahash_tfm is set */
  44         u8 *root_digest;        /* digest of the root block */
  45         u8 *salt;               /* salt: its size is salt_size */
  46         u8 *initial_hashstate;  /* salted initial state, if shash_tfm is set */
  47         u8 *zero_digest;        /* digest for a zero block */
  48 #ifdef CONFIG_SECURITY
  49         u8 *root_digest_sig;    /* signature of the root digest */
  50         unsigned int sig_size;  /* root digest signature size */
  51 #endif /* CONFIG_SECURITY */
  52         unsigned int salt_size;
  53         sector_t data_start;    /* data offset in 512-byte sectors */
  54         sector_t hash_start;    /* hash start in blocks */
  55         sector_t data_blocks;   /* the number of data blocks */
  56         sector_t hash_blocks;   /* the number of hash blocks */
  57         unsigned char data_dev_block_bits;      /* log2(data blocksize) */
  58         unsigned char hash_dev_block_bits;      /* log2(hash blocksize) */
  59         unsigned char hash_per_block_bits;      /* log2(hashes in hash block) */
  60         unsigned char levels;   /* the number of tree levels */
  61         unsigned char version;
  62         bool hash_failed:1;     /* set if hash of any block failed */
  63         bool use_bh_wq:1;       /* try to verify in BH wq before normal work-queue */
  64         unsigned int digest_size;       /* digest size for the current hash algorithm */
  65         unsigned int hash_reqsize; /* the size of temporary space for crypto */
  66         enum verity_mode mode;  /* mode for handling verification errors */
  67         unsigned int corrupted_errs;/* Number of errors for corrupted blocks */
  68
  69         struct workqueue_struct *verify_wq;
  70
  71         /* starting blocks for each tree level. 0 is the lowest level. */
  72         sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
  73
  74         struct dm_verity_fec *fec;      /* forward error correction */
  75         unsigned long *validated_blocks; /* bitset blocks validated */
  76
  77         char *signature_key_desc; /* signature keyring reference */
  78
  79         struct dm_io_client *io;
  80         mempool_t recheck_pool;
  81 };
  82
  83 struct dm_verity_io {
  84         struct dm_verity *v;
  85
  86         /* original value of bio->bi_end_io */
  87         bio_end_io_t *orig_bi_end_io;
  88
  89         struct bvec_iter iter;
  90
  91         sector_t block;
  92         unsigned int n_blocks;
  93         bool in_bh;
  94
  95         struct work_struct work;
  96         struct work_struct bh_work;
  97
  98         u8 real_digest[HASH_MAX_DIGESTSIZE];
  99         u8 want_digest[HASH_MAX_DIGESTSIZE];
 100
 101         /*
 102          * This struct is followed by a variable-sized hash request of size
 103          * v->hash_reqsize, either a struct ahash_request or a struct shash_desc
 104          * (depending on whether ahash_tfm or shash_tfm is being used).  To
 105          * access it, use verity_io_hash_req().
 106          */
 107 };
 108
 109 static inline void *verity_io_hash_req(struct dm_verity *v,
 110                                        struct dm_verity_io *io)
 111 {
 112         return io + 1;
 113 }
 114
 115 static inline u8 *verity_io_real_digest(struct dm_verity *v,
 116                                         struct dm_verity_io *io)
 117 {
 118         return io->real_digest;
 119 }
 120
 121 static inline u8 *verity_io_want_digest(struct dm_verity *v,
 122                                         struct dm_verity_io *io)
 123 {
 124         return io->want_digest;
 125 }
 126
 127 extern int verity_hash(struct dm_verity *v, struct dm_verity_io *io,
 128                        const u8 *data, size_t len, u8 *digest, bool may_sleep);
 129
 130 extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
 131                                  sector_t block, u8 *digest, bool *is_zero);
 132
 133 extern bool dm_is_verity_target(struct dm_target *ti);
 134 extern int dm_verity_get_mode(struct dm_target *ti);
 135 extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest,
 136                                      unsigned int *digest_size);
 137
 138 #endif /* DM_VERITY_H */