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916ef6232c
Verity targets can be configured to ignore corrupted data blocks.
LoadPin must only trust verity targets that are configured to
perform some kind of enforcement when data corruption is detected,
like returning an error, restarting the system or triggering a
panic.
Fixes: b6c1c5745c ("dm: Add verity helpers for LoadPin")
Reported-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220907133055.1.Ic8a1dafe960dc0f8302e189642bc88ebb785d274@changeid
142 lines
4.0 KiB
C
142 lines
4.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2012 Red Hat, Inc.
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* Copyright (C) 2015 Google, Inc.
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*
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* Author: Mikulas Patocka <mpatocka@redhat.com>
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*
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* Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
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*/
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#ifndef DM_VERITY_H
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#define DM_VERITY_H
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#include <linux/dm-bufio.h>
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#include <linux/device-mapper.h>
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#include <linux/interrupt.h>
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#include <crypto/hash.h>
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#define DM_VERITY_MAX_LEVELS 63
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enum verity_mode {
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DM_VERITY_MODE_EIO,
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DM_VERITY_MODE_LOGGING,
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DM_VERITY_MODE_RESTART,
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DM_VERITY_MODE_PANIC
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};
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enum verity_block_type {
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DM_VERITY_BLOCK_TYPE_DATA,
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DM_VERITY_BLOCK_TYPE_METADATA
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};
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struct dm_verity_fec;
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struct dm_verity {
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struct dm_dev *data_dev;
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struct dm_dev *hash_dev;
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struct dm_target *ti;
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struct dm_bufio_client *bufio;
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char *alg_name;
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struct crypto_ahash *tfm;
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u8 *root_digest; /* digest of the root block */
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u8 *salt; /* salt: its size is salt_size */
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u8 *zero_digest; /* digest for a zero block */
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unsigned salt_size;
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sector_t data_start; /* data offset in 512-byte sectors */
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sector_t hash_start; /* hash start in blocks */
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sector_t data_blocks; /* the number of data blocks */
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sector_t hash_blocks; /* the number of hash blocks */
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unsigned char data_dev_block_bits; /* log2(data blocksize) */
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unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
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unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
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unsigned char levels; /* the number of tree levels */
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unsigned char version;
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bool hash_failed:1; /* set if hash of any block failed */
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bool use_tasklet:1; /* try to verify in tasklet before work-queue */
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unsigned digest_size; /* digest size for the current hash algorithm */
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unsigned int ahash_reqsize;/* the size of temporary space for crypto */
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enum verity_mode mode; /* mode for handling verification errors */
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unsigned corrupted_errs;/* Number of errors for corrupted blocks */
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struct workqueue_struct *verify_wq;
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/* starting blocks for each tree level. 0 is the lowest level. */
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sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
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struct dm_verity_fec *fec; /* forward error correction */
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unsigned long *validated_blocks; /* bitset blocks validated */
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char *signature_key_desc; /* signature keyring reference */
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};
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struct dm_verity_io {
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struct dm_verity *v;
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/* original value of bio->bi_end_io */
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bio_end_io_t *orig_bi_end_io;
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sector_t block;
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unsigned n_blocks;
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bool in_tasklet;
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struct bvec_iter iter;
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struct work_struct work;
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struct tasklet_struct tasklet;
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/*
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* Three variably-size fields follow this struct:
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*
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* u8 hash_req[v->ahash_reqsize];
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* u8 real_digest[v->digest_size];
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* u8 want_digest[v->digest_size];
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*
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* To access them use: verity_io_hash_req(), verity_io_real_digest()
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* and verity_io_want_digest().
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*/
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};
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static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v,
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struct dm_verity_io *io)
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{
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return (struct ahash_request *)(io + 1);
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}
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static inline u8 *verity_io_real_digest(struct dm_verity *v,
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struct dm_verity_io *io)
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{
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return (u8 *)(io + 1) + v->ahash_reqsize;
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}
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static inline u8 *verity_io_want_digest(struct dm_verity *v,
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struct dm_verity_io *io)
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{
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return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size;
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}
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static inline u8 *verity_io_digest_end(struct dm_verity *v,
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struct dm_verity_io *io)
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{
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return verity_io_want_digest(v, io) + v->digest_size;
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}
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extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
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struct bvec_iter *iter,
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int (*process)(struct dm_verity *v,
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struct dm_verity_io *io,
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u8 *data, size_t len));
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extern int verity_hash(struct dm_verity *v, struct ahash_request *req,
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const u8 *data, size_t len, u8 *digest);
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extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
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sector_t block, u8 *digest, bool *is_zero);
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extern bool dm_is_verity_target(struct dm_target *ti);
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extern int dm_verity_get_mode(struct dm_target *ti);
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extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest,
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unsigned int *digest_size);
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#endif /* DM_VERITY_H */
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