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/* Copyright 2015 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* Boot descriptor block firmware functions
*/
#ifndef VBOOT_REFERENCE_BDB_H_
#define VBOOT_REFERENCE_BDB_H_
#include <stdlib.h>
#include "bdb_struct.h"
/*****************************************************************************/
/*
Expected calling sequence:
Load and check just the header
bdb_check_header(buf, size);
Load and verify the entire BDB
bdb_verify(buf, size, bdb_key_hash, dev_mode_flag);
Check RW datakey version. If normal boot from primary BDB, roll forward
Check data version. If normal boot from primary BDB, roll forward
*/
/*****************************************************************************/
/* Codes for functions returning numeric error codes */
enum bdb_return_code {
/* Success */
BDB_SUCCESS = 0,
/* BDB key did not match hash, but other than that the BDB was
* fully verified. */
BDB_GOOD_OTHER_THAN_KEY = 1,
/* Other errors */
BDB_ERROR_UNKNOWN = 100,
/* Buffer size too small or wraps around */
BDB_ERROR_BUF_SIZE,
/* Bad fields in structures */
BDB_ERROR_STRUCT_MAGIC,
BDB_ERROR_STRUCT_VERSION,
BDB_ERROR_STRUCT_SIZE,
BDB_ERROR_SIGNED_SIZE,
BDB_ERROR_BDB_SIZE,
BDB_ERROR_OEM_AREA_SIZE,
BDB_ERROR_HASH_ENTRY_SIZE,
BDB_ERROR_HASH_ALG,
BDB_ERROR_SIG_ALG,
BDB_ERROR_DESCRIPTION,
/* Bad components of BDB in bdb_verify() */
BDB_ERROR_HEADER,
BDB_ERROR_BDBKEY,
BDB_ERROR_OEM_AREA_0,
BDB_ERROR_DATAKEY,
BDB_ERROR_BDB_SIGNED_SIZE,
BDB_ERROR_HEADER_SIG,
BDB_ERROR_DATA,
BDB_ERROR_DATA_SIG,
/* Other errors in bdb_verify() */
BDB_ERROR_DIGEST, /* Error calculating digest */
BDB_ERROR_VERIFY_SIG, /* Error verifying signature */
};
/*****************************************************************************/
/* Functions */
/**
* Sanity-check BDB structures.
*
* This checks for known version numbers, magic numbers, algorithms, etc. and
* ensures the sizes are consistent with those parameters.
*
* @param p Pointer to structure to check
* @param size Size of structure buffer
* @return 0 if success, non-zero error code if error.
*/
int bdb_check_header(const struct bdb_header *p, size_t size);
int bdb_check_key(const struct bdb_key *p, size_t size);
int bdb_check_sig(const struct bdb_sig *p, size_t size);
int bdb_check_data(const struct bdb_data *p, size_t size);
/**
* Verify the entire BDB
*
* @param buf Data to hash
* @param size Size of data in bytes
* @param bdb_key_digest Pointer to expected digest for BDB key.
* Must be BDB_SHA256_DIGEST_SIZE bytes long.
*
* @return 0 if success, non-zero error code if error. Note that error code
* BDB_GOOD_OTHER_THAN_KEY may still indicate an acceptable BDB if the Boot
* Verified fuse has not been set, or in developer mode.
*/
int bdb_verify(const void *buf, size_t size, const uint8_t *bdb_key_digest);
/**
* Functions to extract things from a verified BDB buffer.
*
* Do not call these externally until after bdb_verify()! These methods
* assume data structures have already been verified.
*
* @param buf Pointer to BDB buffer
* @param type Data type, for bdb_get_hash()
* @return A pointer to the requested data, or NULL if error / not present.
*/
const struct bdb_header *bdb_get_header(const void *buf);
const struct bdb_key *bdb_get_bdbkey(const void *buf);
const void *bdb_get_oem_area_0(const void *buf);
const struct bdb_key *bdb_get_datakey(const void *buf);
const struct bdb_sig *bdb_get_header_sig(const void *buf);
const struct bdb_data *bdb_get_data(const void *buf);
const void *bdb_get_oem_area_1(const void *buf);
const struct bdb_hash *bdb_get_hash(const void *buf, enum bdb_data_type type);
const struct bdb_sig *bdb_get_data_sig(const void *buf);
/*****************************************************************************/
/* Functions probably provided by the caller */
/**
* Calculate a SHA-256 digest of a buffer.
*
* @param digest Pointer to the digest buffer. Must be
* BDB_SHA256_DIGEST_SIZE bytes long.
* @param buf Data to hash
* @param size Size of data in bytes
* @return 0 if success, non-zero error code if error.
*/
__attribute__((weak))
int bdb_sha256(void *digest, const void *buf, size_t size);
/**
* Verify a RSA-4096 signed digest
*
* @param key_data Key data to use (BDB_RSA4096_KEY_DATA_SIZE bytes)
* @param sig_data Signature to verify (BDB_RSA4096_SIG_SIZE bytes)
* @param digest Digest of signed data (BDB_SHA256_DIGEST bytes)
* @return 0 if success, non-zero error code if error.
*/
__attribute__((weak))
int bdb_rsa4096_verify(const uint8_t *key_data,
const uint8_t *sig,
const uint8_t *digest);
/**
* Verify a RSA-3072B signed digest
*
* @param key_data Key data to use (BDB_RSA3072B_KEY_DATA_SIZE bytes)
* @param sig_data Signature to verify (BDB_RSA3072B_SIG_SIZE bytes)
* @param digest Digest of signed data (BDB_SHA256_DIGEST bytes)
* @return 0 if success, non-zero error code if error.
*/
__attribute__((weak))
int bdb_rsa3072b_verify(const uint8_t *key_data,
const uint8_t *sig,
const uint8_t *digest);
/**
* Verify a ECDSA-521 signed digest
*
* @param key_data Key data to use (BDB_ECDSA521_KEY_DATA_SIZE bytes)
* @param sig_data Signature to verify (BDB_ECDSA521_SIG_SIZE bytes)
* @param digest Digest of signed data (BDB_SHA256_DIGEST bytes)
* @return 0 if success, non-zero error code if error.
*/
__attribute__((weak))
int bdb_ecdsa521_verify(const uint8_t *key_data,
const uint8_t *sig,
const uint8_t *digest);
/*****************************************************************************/
#endif /* VBOOT_REFERENCE_BDB_H_ */
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