firmware/lib20/include/vb2_common.h

/* Copyright (c) 2014 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.
 *
 * Common functions between firmware and kernel verified boot.
 */

#ifndef VBOOT_REFERENCE_VB2_COMMON_H_
#define VBOOT_REFERENCE_VB2_COMMON_H_

#include "2api.h"
#include "2common.h"
#include "2return_codes.h"
#include "2sha.h"
#include "2struct.h"
#include "2sysincludes.h"
#include "vb2_struct.h"

struct vb2_public_key;

/*
 * Helper functions to get data pointed to by a public key or signature.
 */

uint8_t *vb2_signature_data(struct vb2_signature *sig);

/**
 * Verify a signature is fully contained in its parent data
 *
 * @param parent	Parent data
 * @param parent_size	Parent size in bytes
 * @param sig		Signature pointer
 * @return VB2_SUCCESS, or non-zero if error.
 */
vb2_error_t vb2_verify_signature_inside(const void *parent,
					uint32_t parent_size,
					const struct vb2_signature *sig);

/**
 * Unpack a vboot1-format key buffer for use in verification
 *
 * The elements of the unpacked key will point into the source buffer, so don't
 * free the source buffer until you're done with the key.
 *
 * @param key		Destintion for unpacked key
 * @param buf		Source buffer containing packed key
 * @param size		Size of buffer in bytes
 * @return VB2_SUCCESS, or non-zero error code if error.
 */
vb2_error_t vb2_unpack_key_buffer(struct vb2_public_key *key,
				  const uint8_t *buf, uint32_t size);

/**
 * Unpack a vboot1-format key for use in verification
 *
 * The elements of the unpacked key will point into the source packed key, so
 * don't free the source until you're done with the public key.
 *
 * @param key		Destintion for unpacked key
 * @param packed_key	Source packed key
 * @param size		Size of buffer in bytes
 * @return VB2_SUCCESS, or non-zero error code if error.
 */
vb2_error_t vb2_unpack_key(struct vb2_public_key *key,
			   const struct vb2_packed_key *packed_key);

/**
 * Verify a signature against an expected hash digest.
 *
 * @param key		Key to use in signature verification
 * @param sig		Signature to verify (may be destroyed in process)
 * @param digest	Digest of signed data
 * @param wb		Work buffer
 * @return VB2_SUCCESS, or non-zero if error.
 */
vb2_error_t vb2_verify_digest(const struct vb2_public_key *key,
			      struct vb2_signature *sig, const uint8_t *digest,
			      const struct vb2_workbuf *wb);

/**
 * Verify data matches signature.
 *
 * @param data		Data to verify
 * @param size		Size of data buffer.  Note that amount of data to
 *			actually validate is contained in sig->data_size.
 * @param sig		Signature of data (destroyed in process)
 * @param key		Key to use to validate signature
 * @param wb		Work buffer
 * @return VB2_SUCCESS, or non-zero error code if error.
 */
vb2_error_t vb2_verify_data(const uint8_t *data, uint32_t size,
			    struct vb2_signature *sig,
			    const struct vb2_public_key *key,
			    const struct vb2_workbuf *wb);

/**
 * Check the sanity of a key block structure.
 *
 * Verifies all the header fields.  Does not verify key index or key block
 * flags.  Should be called before verifying the key block data itself using
 * the key.  (This function does not itself verify the signature - just that
 * the right amount of data is claimed to be signed.)
 *
 * @param block		Key block to verify
 * @param size		Size of key block buffer
 * @param sig		Which signature inside the keyblock to use
 */
vb2_error_t vb2_check_keyblock(const struct vb2_keyblock *block, uint32_t size,
			       const struct vb2_signature *sig);

/**
 * Verify a key block using a public key.
 *
 * Header fields are also checked for sanity.  Does not verify key index or key
 * block flags.  Signature inside block is destroyed during check.
 *
 * @param block		Key block to verify
 * @param size		Size of key block buffer
 * @param key		Key to use to verify block
 * @param wb		Work buffer
 * @return VB2_SUCCESS, or non-zero error code if error.
 */
vb2_error_t vb2_verify_keyblock(struct vb2_keyblock *block, uint32_t size,
				const struct vb2_public_key *key,
				const struct vb2_workbuf *wb);

/**
 * Verify a key block using its hash.
 *
 * Header fields are also checked for sanity.  Does not verify key index or key
 * block flags.  Use this for self-signed keyblocks in developer mode.
 *
 * @param block		Key block to verify
 * @param size		Size of key block buffer
 * @param key		Key to use to verify block
 * @param wb		Work buffer
 * @return VB2_SUCCESS, or non-zero error code if error.
 */
vb2_error_t vb2_verify_keyblock_hash(const struct vb2_keyblock *block,
				     uint32_t size,
				     const struct vb2_workbuf *wb);

/**
 * Check the sanity of a firmware preamble using a public key.
 *
 * The signature in the preamble is destroyed during the check.
 *
 * @param preamble     	Preamble to verify
 * @param size		Size of preamble buffer
 * @param key		Key to use to verify preamble
 * @param wb		Work buffer
 * @return VB2_SUCCESS, or non-zero error code if error.
 */
vb2_error_t vb2_verify_fw_preamble(struct vb2_fw_preamble *preamble,
				   uint32_t size,
				   const struct vb2_public_key *key,
				   const struct vb2_workbuf *wb);

/**
 * Check the sanity of a kernel preamble using a public key.
 *
 * The signature in the preamble is destroyed during the check.
 *
 * @param preamble     	Preamble to verify
 * @param size		Size of preamble buffer
 * @param key		Key to use to verify preamble
 * @param wb		Work buffer
 * @return VB2_SUCCESS, or non-zero error code if error.
 */
vb2_error_t vb2_verify_kernel_preamble(struct vb2_kernel_preamble *preamble,
				       uint32_t size,
				       const struct vb2_public_key *key,
				       const struct vb2_workbuf *wb);

/**
 * Retrieve the 16-bit vmlinuz header address and size from the preamble.
 *
 * Size 0 means there is no 16-bit vmlinuz header present.  Old preamble
 * versions (<2.1) return 0 for both fields.
 *
 * @param preamble	Preamble to check
 * @param vmlinuz_header_address	Destination for header address
 * @param vmlinuz_header_size		Destination for header size
 */
void vb2_kernel_get_vmlinuz_header(const struct vb2_kernel_preamble *preamble,
				   uint64_t *vmlinuz_header_address,
				   uint32_t *vmlinuz_header_size);

/**
 * Get the flags for the kernel preamble.
 *
 * @param preamble	Preamble to check
 * @return Flags for the preamble.  Old preamble versions (<2.2) return 0.
 */
uint32_t vb2_kernel_get_flags(const struct vb2_kernel_preamble *preamble);

#endif  /* VBOOT_REFERENCE_VB2_COMMON_H_ */