summaryrefslogtreecommitdiffstats
path: root/drivers/md/dm-verity.h
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/md/dm-verity.h')
-rw-r--r--drivers/md/dm-verity.h135
1 files changed, 135 insertions, 0 deletions
diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h
new file mode 100644
index 0000000000..f9d522c870
--- /dev/null
+++ b/drivers/md/dm-verity.h
@@ -0,0 +1,135 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ * Copyright (C) 2015 Google, Inc.
+ *
+ * Author: Mikulas Patocka <mpatocka@redhat.com>
+ *
+ * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
+ */
+
+#ifndef DM_VERITY_H
+#define DM_VERITY_H
+
+#include <linux/dm-bufio.h>
+#include <linux/device-mapper.h>
+#include <linux/interrupt.h>
+#include <crypto/hash.h>
+
+#define DM_VERITY_MAX_LEVELS 63
+
+enum verity_mode {
+ DM_VERITY_MODE_EIO,
+ DM_VERITY_MODE_LOGGING,
+ DM_VERITY_MODE_RESTART,
+ DM_VERITY_MODE_PANIC
+};
+
+enum verity_block_type {
+ DM_VERITY_BLOCK_TYPE_DATA,
+ DM_VERITY_BLOCK_TYPE_METADATA
+};
+
+struct dm_verity_fec;
+
+struct dm_verity {
+ struct dm_dev *data_dev;
+ struct dm_dev *hash_dev;
+ struct dm_target *ti;
+ struct dm_bufio_client *bufio;
+ char *alg_name;
+ struct crypto_ahash *tfm;
+ u8 *root_digest; /* digest of the root block */
+ u8 *salt; /* salt: its size is salt_size */
+ u8 *zero_digest; /* digest for a zero block */
+ unsigned int salt_size;
+ sector_t data_start; /* data offset in 512-byte sectors */
+ sector_t hash_start; /* hash start in blocks */
+ sector_t data_blocks; /* the number of data blocks */
+ sector_t hash_blocks; /* the number of hash blocks */
+ unsigned char data_dev_block_bits; /* log2(data blocksize) */
+ unsigned char hash_dev_block_bits; /* log2(hash blocksize) */
+ unsigned char hash_per_block_bits; /* log2(hashes in hash block) */
+ unsigned char levels; /* the number of tree levels */
+ unsigned char version;
+ bool hash_failed:1; /* set if hash of any block failed */
+ bool use_tasklet:1; /* try to verify in tasklet before work-queue */
+ unsigned int digest_size; /* digest size for the current hash algorithm */
+ unsigned int ahash_reqsize;/* the size of temporary space for crypto */
+ enum verity_mode mode; /* mode for handling verification errors */
+ unsigned int corrupted_errs;/* Number of errors for corrupted blocks */
+
+ struct workqueue_struct *verify_wq;
+
+ /* starting blocks for each tree level. 0 is the lowest level. */
+ sector_t hash_level_block[DM_VERITY_MAX_LEVELS];
+
+ struct dm_verity_fec *fec; /* forward error correction */
+ unsigned long *validated_blocks; /* bitset blocks validated */
+
+ char *signature_key_desc; /* signature keyring reference */
+};
+
+struct dm_verity_io {
+ struct dm_verity *v;
+
+ /* original value of bio->bi_end_io */
+ bio_end_io_t *orig_bi_end_io;
+
+ sector_t block;
+ unsigned int n_blocks;
+ bool in_tasklet;
+
+ struct bvec_iter iter;
+
+ struct work_struct work;
+ struct tasklet_struct tasklet;
+
+ /*
+ * Three variably-size fields follow this struct:
+ *
+ * u8 hash_req[v->ahash_reqsize];
+ * u8 real_digest[v->digest_size];
+ * u8 want_digest[v->digest_size];
+ *
+ * To access them use: verity_io_hash_req(), verity_io_real_digest()
+ * and verity_io_want_digest().
+ */
+};
+
+static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v,
+ struct dm_verity_io *io)
+{
+ return (struct ahash_request *)(io + 1);
+}
+
+static inline u8 *verity_io_real_digest(struct dm_verity *v,
+ struct dm_verity_io *io)
+{
+ return (u8 *)(io + 1) + v->ahash_reqsize;
+}
+
+static inline u8 *verity_io_want_digest(struct dm_verity *v,
+ struct dm_verity_io *io)
+{
+ return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size;
+}
+
+extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
+ struct bvec_iter *iter,
+ int (*process)(struct dm_verity *v,
+ struct dm_verity_io *io,
+ u8 *data, size_t len));
+
+extern int verity_hash(struct dm_verity *v, struct ahash_request *req,
+ const u8 *data, size_t len, u8 *digest, bool may_sleep);
+
+extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
+ sector_t block, u8 *digest, bool *is_zero);
+
+extern bool dm_is_verity_target(struct dm_target *ti);
+extern int dm_verity_get_mode(struct dm_target *ti);
+extern int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest,
+ unsigned int *digest_size);
+
+#endif /* DM_VERITY_H */