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/*
* Copyright (C) 2015 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#ifndef DM_ANDROID_VERITY_H
#define DM_ANDROID_VERITY_H
#include <crypto/sha.h>
#define RSANUMBYTES 256
#define VERITY_METADATA_MAGIC_NUMBER 0xb001b001
#define VERITY_METADATA_MAGIC_DISABLE 0x46464f56
#define VERITY_METADATA_VERSION 0
#define VERITY_STATE_DISABLE 1
#define DATA_BLOCK_SIZE (4 * 1024)
#define VERITY_METADATA_SIZE (8 * DATA_BLOCK_SIZE)
#define VERITY_TABLE_ARGS 10
#define VERITY_COMMANDLINE_PARAM_LENGTH 20
#define BUILD_VARIANT 20
/*
* <subject>:<sha1-id> is the format for the identifier.
* subject can either be the Common Name(CN) + Organization Name(O) or
* just the CN if the it is prefixed with O
* From https://tools.ietf.org/html/rfc5280#appendix-A
* ub-organization-name-length INTEGER ::= 64
* ub-common-name-length INTEGER ::= 64
*
* http://lxr.free-electrons.com/source/crypto/asymmetric_keys/x509_cert_parser.c?v=3.9#L278
* ctx->o_size + 2 + ctx->cn_size + 1
* + 41 characters for ":" and sha1 id
* 64 + 2 + 64 + 1 + 1 + 40 (172)
* setting VERITY_DEFAULT_KEY_ID_LENGTH to 200 characters.
*/
#define VERITY_DEFAULT_KEY_ID_LENGTH 200
#define FEC_MAGIC 0xFECFECFE
#define FEC_BLOCK_SIZE (4 * 1024)
#define FEC_VERSION 0
#define FEC_RSM 255
#define FEC_ARG_LENGTH 300
#define VERITY_TABLE_OPT_RESTART "restart_on_corruption"
#define VERITY_TABLE_OPT_LOGGING "ignore_corruption"
#define VERITY_TABLE_OPT_IGNZERO "ignore_zero_blocks"
#define VERITY_TABLE_OPT_FEC_FORMAT \
"use_fec_from_device %s fec_start %llu fec_blocks %llu fec_roots %u ignore_zero_blocks"
#define VERITY_TABLE_OPT_FEC_ARGS 9
#define VERITY_DEBUG 0
#define DM_MSG_PREFIX "android-verity"
#define DM_LINEAR_ARGS 2
#define DM_LINEAR_TARGET_OFFSET "0"
/*
* There can be two formats.
* if fec is present
* <data_blocks> <verity_tree> <verity_metdata_32K><fec_data><fec_data_4K>
* if fec is not present
* <data_blocks> <verity_tree> <verity_metdata_32K>
*/
struct fec_header {
__le32 magic;
__le32 version;
__le32 size;
__le32 roots;
__le32 fec_size;
__le64 inp_size;
u8 hash[SHA256_DIGEST_SIZE];
} __attribute__((packed));
struct android_metadata_header {
__le32 magic_number;
__le32 protocol_version;
char signature[RSANUMBYTES];
__le32 table_length;
};
struct android_metadata {
struct android_metadata_header *header;
char *verity_table;
};
struct fec_ecc_metadata {
bool valid;
u32 roots;
u64 blocks;
u64 rounds;
u64 start;
};
struct bio_read {
struct page **page_io;
int number_of_pages;
};
extern struct target_type linear_target;
extern void dm_linear_dtr(struct dm_target *ti);
extern int dm_linear_map(struct dm_target *ti, struct bio *bio);
extern void dm_linear_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen);
extern int dm_linear_prepare_ioctl(struct dm_target *ti,
struct block_device **bdev, fmode_t *mode);
extern int dm_linear_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data);
extern int dm_linear_ctr(struct dm_target *ti, unsigned int argc, char **argv);
#endif /* DM_ANDROID_VERITY_H */
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