1/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
2 * Use of this source code is governed by a BSD-style license that can be
3 * found in the LICENSE file.
4 */
5
6#ifndef VBOOT_REFERENCE_2RSA_H_
7#define VBOOT_REFERENCE_2RSA_H_
8
9#include "2crypto.h"
10#include "2struct.h"
11
12struct vb2_workbuf;
13
14/* Public key structure in RAM */
15struct vb2_public_key {
16	uint32_t arrsize;    /* Length of n[] and rr[] in number of uint32_t */
17	uint32_t n0inv;      /* -1 / n[0] mod 2^32 */
18	const uint32_t *n;   /* Modulus as little endian array */
19	const uint32_t *rr;  /* R^2 as little endian array */
20	enum vb2_signature_algorithm sig_alg;  /* Signature algorithm */
21	enum vb2_hash_algorithm hash_alg;      /* Hash algorithm */
22	const char *desc;            /* Description */
23	uint32_t version;            /* Key version */
24	const struct vb2_guid *guid; /* Key GUID */
25};
26
27/**
28 * Convert vb2_crypto_algorithm to vb2_signature_algorithm.
29 *
30 * @param algorithm	Crypto algorithm (vb2_crypto_algorithm)
31 *
32 * @return The signature algorithm for that crypto algorithm, or
33 * VB2_SIG_INVALID if the crypto algorithm or its corresponding signature
34 * algorithm is invalid or not supported.
35 */
36enum vb2_signature_algorithm vb2_crypto_to_signature(uint32_t algorithm);
37
38/**
39 * Return the size of a RSA signature
40 *
41 * @param sig_alg	Signature algorithm
42 * @return The size of the signature in bytes, or 0 if error.
43 */
44uint32_t vb2_rsa_sig_size(enum vb2_signature_algorithm sig_alg);
45
46/**
47 * Return the size of a pre-processed RSA public key.
48 *
49 * @param sig_alg	Signature algorithm
50 * @return The size of the preprocessed key in bytes, or 0 if error.
51 */
52uint32_t vb2_packed_key_size(enum vb2_signature_algorithm sig_alg);
53
54/**
55 * Check pkcs 1.5 padding bytes
56 *
57 * @param sig		Signature to verify
58 * @param key		Key to take signature and hash algorithms from
59 * @return VB2_SUCCESS, or non-zero if error.
60 */
61int vb2_check_padding(const uint8_t *sig, const struct vb2_public_key *key);
62
63/* Size of work buffer sufficient for vb2_rsa_verify_digest() worst case */
64#define VB2_VERIFY_RSA_DIGEST_WORKBUF_BYTES (3 * 1024)
65
66/**
67 * Verify a RSA PKCS1.5 signature against an expected hash digest.
68 *
69 * @param key		Key to use in signature verification
70 * @param sig		Signature to verify (destroyed in process)
71 * @param digest	Digest of signed data
72 * @param wb		Work buffer
73 * @return VB2_SUCCESS, or non-zero if error.
74 */
75int vb2_rsa_verify_digest(const struct vb2_public_key *key,
76			  uint8_t *sig,
77			  const uint8_t *digest,
78			  const struct vb2_workbuf *wb);
79
80#endif  /* VBOOT_REFERENCE_2RSA_H_ */
81