/* 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.
 *
 * Utility functions for message digest functions.
 */

#include "2common.h"
#include "2sha.h"
#include "2sysincludes.h"

size_t vb2_digest_size(enum vb2_hash_algorithm hash_alg)
{
	switch (hash_alg) {
#if VB2_SUPPORT_SHA1
	case VB2_HASH_SHA1:
		return VB2_SHA1_DIGEST_SIZE;
#endif
#if VB2_SUPPORT_SHA256
	case VB2_HASH_SHA224:
		return VB2_SHA224_DIGEST_SIZE;
	case VB2_HASH_SHA256:
		return VB2_SHA256_DIGEST_SIZE;
#endif
#if VB2_SUPPORT_SHA512
	case VB2_HASH_SHA384:
		return VB2_SHA384_DIGEST_SIZE;
	case VB2_HASH_SHA512:
		return VB2_SHA512_DIGEST_SIZE;
#endif
	default:
		return 0;
	}
}

size_t vb2_hash_block_size(enum vb2_hash_algorithm alg)
{
	switch (alg) {
#if VB2_SUPPORT_SHA1
	case VB2_HASH_SHA1:
		return VB2_SHA1_BLOCK_SIZE;
#endif
#if VB2_SUPPORT_SHA256
	case VB2_HASH_SHA224:	/* SHA224 reuses SHA256 internal structures */
	case VB2_HASH_SHA256:
		return VB2_SHA256_BLOCK_SIZE;
#endif
#if VB2_SUPPORT_SHA512
	case VB2_HASH_SHA384:	/* SHA384 reuses SHA512 internal structures */
	case VB2_HASH_SHA512:
		return VB2_SHA512_BLOCK_SIZE;
#endif
	default:
		return 0;
	}
}

test_mockable
vb2_error_t vb2_digest_init(struct vb2_digest_context *dc,
			    enum vb2_hash_algorithm hash_alg)
{
	dc->hash_alg = hash_alg;
	dc->using_hwcrypto = 0;

	switch (dc->hash_alg) {
#if VB2_SUPPORT_SHA1
	case VB2_HASH_SHA1:
		vb2_sha1_init(&dc->sha1);
		return VB2_SUCCESS;
#endif
#if VB2_SUPPORT_SHA256
	case VB2_HASH_SHA224:
	case VB2_HASH_SHA256:
		vb2_sha256_init(&dc->sha256, hash_alg);
		return VB2_SUCCESS;
#endif
#if VB2_SUPPORT_SHA512
	case VB2_HASH_SHA384:
	case VB2_HASH_SHA512:
		vb2_sha512_init(&dc->sha512, hash_alg);
		return VB2_SUCCESS;
#endif
	default:
		return VB2_ERROR_SHA_INIT_ALGORITHM;
	}
}

test_mockable
vb2_error_t vb2_digest_extend(struct vb2_digest_context *dc, const uint8_t *buf,
			      uint32_t size)
{
	switch (dc->hash_alg) {
#if VB2_SUPPORT_SHA1
	case VB2_HASH_SHA1:
		vb2_sha1_update(&dc->sha1, buf, size);
		return VB2_SUCCESS;
#endif
#if VB2_SUPPORT_SHA256
	case VB2_HASH_SHA224:
	case VB2_HASH_SHA256:
		vb2_sha256_update(&dc->sha256, buf, size);
		return VB2_SUCCESS;
#endif
#if VB2_SUPPORT_SHA512
	case VB2_HASH_SHA384:
	case VB2_HASH_SHA512:
		vb2_sha512_update(&dc->sha512, buf, size);
		return VB2_SUCCESS;
#endif
	default:
		return VB2_ERROR_SHA_EXTEND_ALGORITHM;
	}
}

test_mockable
vb2_error_t vb2_digest_finalize(struct vb2_digest_context *dc, uint8_t *digest,
				uint32_t digest_size)
{
	if (digest_size < vb2_digest_size(dc->hash_alg))
		return VB2_ERROR_SHA_FINALIZE_DIGEST_SIZE;

	switch (dc->hash_alg) {
#if VB2_SUPPORT_SHA1
	case VB2_HASH_SHA1:
		vb2_sha1_finalize(&dc->sha1, digest);
		return VB2_SUCCESS;
#endif
#if VB2_SUPPORT_SHA256
	case VB2_HASH_SHA224:
	case VB2_HASH_SHA256:
		vb2_sha256_finalize(&dc->sha256, digest, dc->hash_alg);
		return VB2_SUCCESS;
#endif
#if VB2_SUPPORT_SHA512
	case VB2_HASH_SHA384:
	case VB2_HASH_SHA512:
		vb2_sha512_finalize(&dc->sha512, digest, dc->hash_alg);
		return VB2_SUCCESS;
#endif
	default:
		return VB2_ERROR_SHA_FINALIZE_ALGORITHM;
	}
}

test_mockable
vb2_error_t vb2_digest_buffer(const uint8_t *buf, uint32_t size,
			      enum vb2_hash_algorithm hash_alg, uint8_t *digest,
			      uint32_t digest_size)
{
	struct vb2_digest_context dc;

	VB2_TRY(vb2_digest_init(&dc, hash_alg));
	VB2_TRY(vb2_digest_extend(&dc, buf, size));

	return vb2_digest_finalize(&dc, digest, digest_size);
}

vb2_error_t vb2_hash_verify(const void *buf, uint32_t size,
			    const struct vb2_hash *hash)
{
	uint8_t hash_buf[VB2_MAX_DIGEST_SIZE];
	size_t hash_size = vb2_digest_size(hash->algo);

	VB2_TRY(vb2_digest_buffer(buf, size, hash->algo, hash_buf, hash_size));
	if (memcmp(hash_buf, hash->raw, hash_size))
		return VB2_ERROR_SHA_MISMATCH;
	else
		return VB2_SUCCESS;
}