1 /* 2 * Copyright (c) 2015-2021, 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 #if TRUSTED_BOARD_BOOT 50 assert(crypto_lib_desc.verify_signature != NULL); 51 assert(crypto_lib_desc.verify_hash != NULL); 52 #endif /* TRUSTED_BOARD_BOOT */ 53 #if MEASURED_BOOT 54 assert(crypto_lib_desc.calc_hash != NULL); 55 #endif /* MEASURED_BOOT */ 56 57 /* Initialize the cryptographic library */ 58 crypto_lib_desc.init(); 59 INFO("Using crypto library '%s'\n", crypto_lib_desc.name); 60 } 61 62 /* 63 * Function to verify a digital signature 64 * 65 * Parameters: 66 * 67 * data_ptr, data_len: signed data 68 * sig_ptr, sig_len: the digital signature 69 * sig_alg_ptr, sig_alg_len: the digital signature algorithm 70 * pk_ptr, pk_len: the public key 71 */ 72 int crypto_mod_verify_signature(void *data_ptr, unsigned int data_len, 73 void *sig_ptr, unsigned int sig_len, 74 void *sig_alg_ptr, unsigned int sig_alg_len, 75 void *pk_ptr, unsigned int pk_len) 76 { 77 assert(data_ptr != NULL); 78 assert(data_len != 0); 79 assert(sig_ptr != NULL); 80 assert(sig_len != 0); 81 assert(sig_alg_ptr != NULL); 82 assert(sig_alg_len != 0); 83 assert(pk_ptr != NULL); 84 assert(pk_len != 0); 85 86 return crypto_lib_desc.verify_signature(data_ptr, data_len, 87 sig_ptr, sig_len, 88 sig_alg_ptr, sig_alg_len, 89 pk_ptr, pk_len); 90 } 91 92 /* 93 * Verify a hash by comparison 94 * 95 * Parameters: 96 * 97 * data_ptr, data_len: data to be hashed 98 * digest_info_ptr, digest_info_len: hash to be compared 99 */ 100 int crypto_mod_verify_hash(void *data_ptr, unsigned int data_len, 101 void *digest_info_ptr, unsigned int digest_info_len) 102 { 103 assert(data_ptr != NULL); 104 assert(data_len != 0); 105 assert(digest_info_ptr != NULL); 106 assert(digest_info_len != 0); 107 108 return crypto_lib_desc.verify_hash(data_ptr, data_len, 109 digest_info_ptr, digest_info_len); 110 } 111 112 #if MEASURED_BOOT 113 /* 114 * Calculate a hash 115 * 116 * Parameters: 117 * 118 * alg: message digest algorithm 119 * data_ptr, data_len: data to be hashed 120 * output: resulting hash 121 */ 122 int crypto_mod_calc_hash(enum crypto_md_algo alg, void *data_ptr, 123 unsigned int data_len, 124 unsigned char output[CRYPTO_MD_MAX_SIZE]) 125 { 126 assert(data_ptr != NULL); 127 assert(data_len != 0); 128 assert(output != NULL); 129 130 return crypto_lib_desc.calc_hash(alg, data_ptr, data_len, output); 131 } 132 #endif /* MEASURED_BOOT */ 133 134 /* 135 * Authenticated decryption of data 136 * 137 * Parameters: 138 * 139 * dec_algo: authenticated decryption algorithm 140 * data_ptr, len: data to be decrypted (inout param) 141 * key, key_len, key_flags: symmetric decryption key 142 * iv, iv_len: initialization vector 143 * tag, tag_len: authentication tag 144 */ 145 int crypto_mod_auth_decrypt(enum crypto_dec_algo dec_algo, void *data_ptr, 146 size_t len, const void *key, unsigned int key_len, 147 unsigned int key_flags, const void *iv, 148 unsigned int iv_len, const void *tag, 149 unsigned int tag_len) 150 { 151 assert(crypto_lib_desc.auth_decrypt != NULL); 152 assert(data_ptr != NULL); 153 assert(len != 0U); 154 assert(key != NULL); 155 assert(key_len != 0U); 156 assert(iv != NULL); 157 assert((iv_len != 0U) && (iv_len <= CRYPTO_MAX_IV_SIZE)); 158 assert(tag != NULL); 159 assert((tag_len != 0U) && (tag_len <= CRYPTO_MAX_TAG_SIZE)); 160 161 return crypto_lib_desc.auth_decrypt(dec_algo, data_ptr, len, key, 162 key_len, key_flags, iv, iv_len, tag, 163 tag_len); 164 } 165