1 /*
2 * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <assert.h>
8 #include <crypto_mod.h>
9 #include <debug.h>
10
11 /* Variable exported by the crypto library through REGISTER_CRYPTO_LIB() */
12 extern const crypto_lib_desc_t crypto_lib_desc;
13
14 /*
15 * The crypto module is responsible for verifying digital signatures and hashes.
16 * It relies on a crypto library to perform the cryptographic operations.
17 *
18 * The crypto module itself does not impose any specific format on signatures,
19 * signature algorithm, keys or hashes, but most cryptographic libraries will
20 * take the parameters as the following DER encoded ASN.1 structures:
21 *
22 * AlgorithmIdentifier ::= SEQUENCE {
23 * algorithm OBJECT IDENTIFIER,
24 * parameters ANY DEFINED BY algorithm OPTIONAL
25 * }
26 *
27 * DigestInfo ::= SEQUENCE {
28 * digestAlgorithm AlgorithmIdentifier,
29 * digest OCTET STRING
30 * }
31 *
32 * SubjectPublicKeyInfo ::= SEQUENCE {
33 * algorithm AlgorithmIdentifier,
34 * subjectPublicKey BIT STRING
35 * }
36 *
37 * SignatureAlgorithm ::= AlgorithmIdentifier
38 *
39 * SignatureValue ::= BIT STRING
40 */
41
42 /*
43 * Perform some static checking and call the library initialization function
44 */
crypto_mod_init(void)45 void crypto_mod_init(void)
46 {
47 assert(crypto_lib_desc.name != NULL);
48 assert(crypto_lib_desc.init != NULL);
49 assert(crypto_lib_desc.verify_signature != NULL);
50 assert(crypto_lib_desc.verify_hash != NULL);
51
52 /* Initialize the cryptographic library */
53 crypto_lib_desc.init();
54 INFO("Using crypto library '%s'\n", crypto_lib_desc.name);
55 }
56
57 /*
58 * Function to verify a digital signature
59 *
60 * Parameters:
61 *
62 * data_ptr, data_len: signed data
63 * sig_ptr, sig_len: the digital signature
64 * sig_alg_ptr, sig_alg_len: the digital signature algorithm
65 * pk_ptr, pk_len: the public key
66 */
crypto_mod_verify_signature(void * data_ptr,unsigned int data_len,void * sig_ptr,unsigned int sig_len,void * sig_alg_ptr,unsigned int sig_alg_len,void * pk_ptr,unsigned int pk_len)67 int crypto_mod_verify_signature(void *data_ptr, unsigned int data_len,
68 void *sig_ptr, unsigned int sig_len,
69 void *sig_alg_ptr, unsigned int sig_alg_len,
70 void *pk_ptr, unsigned int pk_len)
71 {
72 assert(data_ptr != NULL);
73 assert(data_len != 0);
74 assert(sig_ptr != NULL);
75 assert(sig_len != 0);
76 assert(sig_alg_ptr != NULL);
77 assert(sig_alg_len != 0);
78 assert(pk_ptr != NULL);
79 assert(pk_len != 0);
80
81 return crypto_lib_desc.verify_signature(data_ptr, data_len,
82 sig_ptr, sig_len,
83 sig_alg_ptr, sig_alg_len,
84 pk_ptr, pk_len);
85 }
86
87 /*
88 * Verify a hash by comparison
89 *
90 * Parameters:
91 *
92 * data_ptr, data_len: data to be hashed
93 * digest_info_ptr, digest_info_len: hash to be compared
94 */
crypto_mod_verify_hash(void * data_ptr,unsigned int data_len,void * digest_info_ptr,unsigned int digest_info_len)95 int crypto_mod_verify_hash(void *data_ptr, unsigned int data_len,
96 void *digest_info_ptr, unsigned int digest_info_len)
97 {
98 assert(data_ptr != NULL);
99 assert(data_len != 0);
100 assert(digest_info_ptr != NULL);
101 assert(digest_info_len != 0);
102
103 return crypto_lib_desc.verify_hash(data_ptr, data_len,
104 digest_info_ptr, digest_info_len);
105 }
106