1 /*
2 * Copyright (c) 2017-2020 ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <assert.h>
8 #include <stddef.h>
9 #include <string.h>
10
11 #include <drivers/arm/cryptocell/713/bsv_api.h>
12 #include <drivers/arm/cryptocell/713/bsv_crypto_asym_api.h>
13 #include <drivers/auth/crypto_mod.h>
14
15 #include <mbedtls/oid.h>
16
17 #define LIB_NAME "CryptoCell 713 SBROM"
18 #define RSA_SALT_LEN 32
19 #define RSA_EXPONENT 65537
20
21 /*
22 * AlgorithmIdentifier ::= SEQUENCE {
23 * algorithm OBJECT IDENTIFIER,
24 * parameters ANY DEFINED BY algorithm OPTIONAL
25 * }
26 *
27 * SubjectPublicKeyInfo ::= SEQUENCE {
28 * algorithm AlgorithmIdentifier,
29 * subjectPublicKey BIT STRING
30 * }
31 *
32 * DigestInfo ::= SEQUENCE {
33 * digestAlgorithm AlgorithmIdentifier,
34 * digest OCTET STRING
35 * }
36 *
37 * RSASSA-PSS-params ::= SEQUENCE {
38 * hashAlgorithm [0] HashAlgorithm,
39 * maskGenAlgorithm [1] MaskGenAlgorithm,
40 * saltLength [2] INTEGER,
41 * trailerField [3] TrailerField DEFAULT trailerFieldBC
42 * }
43 */
44
45 /*
46 * Initialize the library and export the descriptor
47 */
init(void)48 static void init(void)
49 {
50 CCError_t ret;
51 uint32_t lcs;
52
53 /* Initialize CC SBROM */
54 ret = CC_BsvInit((uintptr_t)PLAT_CRYPTOCELL_BASE);
55 if (ret != CC_OK) {
56 ERROR("CryptoCell CC_BsvInit() error %x\n", ret);
57 panic();
58 }
59
60 /* Initialize lifecycle state */
61 ret = CC_BsvGetAndInitLcs((uintptr_t)PLAT_CRYPTOCELL_BASE, &lcs);
62 if (ret != CC_OK) {
63 ERROR("CryptoCell CC_BsvGetAndInitLcs() error %x\n", ret);
64 panic();
65 }
66 }
67
68 /*
69 * Verify a signature.
70 *
71 * Parameters are passed using the DER encoding format following the ASN.1
72 * structures detailed above.
73 */
verify_signature(void * data_ptr,unsigned int data_len,void * sig_ptr,unsigned int sig_len,void * sig_alg,unsigned int sig_alg_len,void * pk_ptr,unsigned int pk_len)74 static int verify_signature(void *data_ptr, unsigned int data_len,
75 void *sig_ptr, unsigned int sig_len,
76 void *sig_alg, unsigned int sig_alg_len,
77 void *pk_ptr, unsigned int pk_len)
78 {
79 CCError_t error;
80 CCBsvNBuff_t NBuff;
81 CCBsvSignature_t signature;
82 int rc, exp;
83 mbedtls_asn1_buf sig_oid, alg_oid, params;
84 mbedtls_md_type_t md_alg;
85 mbedtls_pk_type_t pk_alg;
86 mbedtls_pk_rsassa_pss_options pss_opts;
87 size_t len;
88 uint8_t *p, *end;
89 CCHashResult_t digest;
90 CCBool_t is_verified;
91 /* This is a rather large array, we don't want it on stack */
92 static uint32_t workspace[BSV_RSA_WORKSPACE_MIN_SIZE];
93
94 /* Verify the signature algorithm */
95 /* Get pointers to signature OID and parameters */
96 p = sig_alg;
97 end = p + sig_alg_len;
98 rc = mbedtls_asn1_get_alg(&p, end, &sig_oid, ¶ms);
99 if (rc != 0)
100 return CRYPTO_ERR_SIGNATURE;
101
102 /* Get the actual signature algorithm (MD + PK) */
103 rc = mbedtls_oid_get_sig_alg(&sig_oid, &md_alg, &pk_alg);
104 if (rc != 0)
105 return CRYPTO_ERR_SIGNATURE;
106
107 /* The CryptoCell only supports RSASSA-PSS signature */
108 if (pk_alg != MBEDTLS_PK_RSASSA_PSS || md_alg != MBEDTLS_MD_NONE)
109 return CRYPTO_ERR_SIGNATURE;
110
111 /* Verify the RSASSA-PSS params */
112 /* The trailer field is verified to be 0xBC internally by this API */
113 rc = mbedtls_x509_get_rsassa_pss_params(¶ms, &md_alg,
114 &pss_opts.mgf1_hash_id,
115 &pss_opts.expected_salt_len);
116 if (rc != 0)
117 return CRYPTO_ERR_SIGNATURE;
118
119 /* The CryptoCell only supports SHA256 as hash algorithm */
120 if (md_alg != MBEDTLS_MD_SHA256 ||
121 pss_opts.mgf1_hash_id != MBEDTLS_MD_SHA256)
122 return CRYPTO_ERR_SIGNATURE;
123
124 if (pss_opts.expected_salt_len != RSA_SALT_LEN)
125 return CRYPTO_ERR_SIGNATURE;
126
127 /* Parse the public key */
128 p = pk_ptr;
129 end = p + pk_len;
130 rc = mbedtls_asn1_get_tag(&p, end, &len,
131 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
132 if (rc != 0)
133 return CRYPTO_ERR_SIGNATURE;
134
135 end = p + len;
136 rc = mbedtls_asn1_get_alg_null(&p, end, &alg_oid);
137 if (rc != 0)
138 return CRYPTO_ERR_SIGNATURE;
139
140 if (mbedtls_oid_get_pk_alg(&alg_oid, &pk_alg) != 0)
141 return CRYPTO_ERR_SIGNATURE;
142
143 if (pk_alg != MBEDTLS_PK_RSA)
144 return CRYPTO_ERR_SIGNATURE;
145
146 rc = mbedtls_asn1_get_bitstring_null(&p, end, &len);
147 if (rc != 0)
148 return CRYPTO_ERR_SIGNATURE;
149
150 rc = mbedtls_asn1_get_tag(&p, end, &len,
151 MBEDTLS_ASN1_CONSTRUCTED |
152 MBEDTLS_ASN1_SEQUENCE);
153 if (rc != 0)
154 return CRYPTO_ERR_SIGNATURE;
155
156 rc = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER);
157 if (rc != 0)
158 return CRYPTO_ERR_SIGNATURE;
159
160 if (*p == 0) {
161 p++; len--;
162 }
163 if (len != BSV_CERT_RSA_KEY_SIZE_IN_BYTES || ((p + len) > end))
164 return CRYPTO_ERR_SIGNATURE;
165
166 /*
167 * Copy N from certificate.
168 */
169 memcpy(NBuff, p, BSV_CERT_RSA_KEY_SIZE_IN_BYTES);
170
171 /* Verify the RSA exponent */
172 p += len;
173 rc = mbedtls_asn1_get_int(&p, end, &exp);
174 if (rc != 0)
175 return CRYPTO_ERR_SIGNATURE;
176
177 if (exp != RSA_EXPONENT)
178 return CRYPTO_ERR_SIGNATURE;
179
180 /* Get the signature (bitstring) */
181 p = sig_ptr;
182 end = p + sig_len;
183 rc = mbedtls_asn1_get_bitstring_null(&p, end, &len);
184 if (rc != 0)
185 return CRYPTO_ERR_SIGNATURE;
186
187 if (len != BSV_CERT_RSA_KEY_SIZE_IN_BYTES || ((p + len) > end))
188 return CRYPTO_ERR_SIGNATURE;
189
190 /*
191 * Copy the signature (in BE format)
192 */
193 memcpy((uint8_t *)signature, p, BSV_CERT_RSA_KEY_SIZE_IN_BYTES);
194
195 error = CC_BsvSha256((uintptr_t)PLAT_CRYPTOCELL_BASE,
196 data_ptr, data_len, digest);
197 if (error != CC_OK)
198 return CRYPTO_ERR_SIGNATURE;
199
200 /* Verify the signature */
201 error = CC_BsvRsaPssVerify((uintptr_t)PLAT_CRYPTOCELL_BASE, NBuff,
202 NULL, signature, digest, workspace,
203 BSV_RSA_WORKSPACE_MIN_SIZE, &is_verified);
204 if ((error != CC_OK) || (is_verified != CC_TRUE))
205 return CRYPTO_ERR_SIGNATURE;
206
207 /* Signature verification success */
208 return CRYPTO_SUCCESS;
209 }
210
211 /*
212 * Match a hash
213 *
214 * Digest info is passed in DER format following the ASN.1 structure detailed
215 * above.
216 */
verify_hash(void * data_ptr,unsigned int data_len,void * digest_info_ptr,unsigned int digest_info_len)217 static int verify_hash(void *data_ptr, unsigned int data_len,
218 void *digest_info_ptr, unsigned int digest_info_len)
219 {
220 mbedtls_asn1_buf hash_oid, params;
221 mbedtls_md_type_t md_alg;
222 uint8_t *p, *end, *hash;
223 CCHashResult_t pubKeyHash;
224 size_t len;
225 int rc;
226 CCError_t error;
227
228 /* Digest info should be an MBEDTLS_ASN1_SEQUENCE */
229 p = digest_info_ptr;
230 end = p + digest_info_len;
231 rc = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
232 MBEDTLS_ASN1_SEQUENCE);
233 if (rc != 0)
234 return CRYPTO_ERR_HASH;
235
236 /* Get the hash algorithm */
237 rc = mbedtls_asn1_get_alg(&p, end, &hash_oid, ¶ms);
238 if (rc != 0)
239 return CRYPTO_ERR_HASH;
240
241 rc = mbedtls_oid_get_md_alg(&hash_oid, &md_alg);
242 if (rc != 0)
243 return CRYPTO_ERR_HASH;
244 /* Verify that hash algorithm is SHA256 */
245 if (md_alg != MBEDTLS_MD_SHA256)
246 return CRYPTO_ERR_HASH;
247
248 /* Hash should be octet string type */
249 rc = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING);
250 if (rc != 0)
251 return CRYPTO_ERR_HASH;
252
253 /* Length of hash must match the algorithm's size */
254 if (len != HASH_RESULT_SIZE_IN_BYTES)
255 return CRYPTO_ERR_HASH;
256
257 hash = p;
258 error = CC_BsvSha256((uintptr_t)PLAT_CRYPTOCELL_BASE, data_ptr,
259 data_len, pubKeyHash);
260 if (error != CC_OK)
261 return CRYPTO_ERR_HASH;
262
263 rc = memcmp(pubKeyHash, hash, HASH_RESULT_SIZE_IN_BYTES);
264 if (rc != 0)
265 return CRYPTO_ERR_HASH;
266
267 return CRYPTO_SUCCESS;
268 }
269
270 /*
271 * Register crypto library descriptor
272 */
273 REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, NULL);
274