1 /* 2 * Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 #include <assert.h> 8 9 #include <common/debug.h> 10 #include <drivers/auth/crypto_mod.h> 11 12 /* Variable exported by the crypto library through REGISTER_CRYPTO_LIB() */ 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 */ 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 */ 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 */ 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 } 106 107 #if MEASURED_BOOT 108 /* 109 * Calculate a hash 110 * 111 * Parameters: 112 * 113 * alg: message digest algorithm 114 * data_ptr, data_len: data to be hashed 115 * output: resulting hash 116 */ 117 int crypto_mod_calc_hash(unsigned int alg, void *data_ptr, 118 unsigned int data_len, unsigned char *output) 119 { 120 assert(data_ptr != NULL); 121 assert(data_len != 0); 122 assert(output != NULL); 123 124 return crypto_lib_desc.calc_hash(alg, data_ptr, data_len, output); 125 } 126 #endif /* MEASURED_BOOT */ 127 128 /* 129 * Authenticated decryption of data 130 * 131 * Parameters: 132 * 133 * dec_algo: authenticated decryption algorithm 134 * data_ptr, len: data to be decrypted (inout param) 135 * key, key_len, key_flags: symmetric decryption key 136 * iv, iv_len: initialization vector 137 * tag, tag_len: authentication tag 138 */ 139 int crypto_mod_auth_decrypt(enum crypto_dec_algo dec_algo, void *data_ptr, 140 size_t len, const void *key, unsigned int key_len, 141 unsigned int key_flags, const void *iv, 142 unsigned int iv_len, const void *tag, 143 unsigned int tag_len) 144 { 145 assert(crypto_lib_desc.auth_decrypt != NULL); 146 assert(data_ptr != NULL); 147 assert(len != 0U); 148 assert(key != NULL); 149 assert(key_len != 0U); 150 assert(iv != NULL); 151 assert((iv_len != 0U) && (iv_len <= CRYPTO_MAX_IV_SIZE)); 152 assert(tag != NULL); 153 assert((tag_len != 0U) && (tag_len <= CRYPTO_MAX_TAG_SIZE)); 154 155 return crypto_lib_desc.auth_decrypt(dec_algo, data_ptr, len, key, 156 key_len, key_flags, iv, iv_len, tag, 157 tag_len); 158 } 159