1 /*
2 * X.509 Certificate Signing Request writing
3 *
4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 * This file is part of mbed TLS (https://tls.mbed.org)
20 */
21 /*
22 * References:
23 * - CSRs: PKCS#10 v1.7 aka RFC 2986
24 * - attributes: PKCS#9 v2.0 aka RFC 2985
25 */
26
27 #if !defined(MBEDTLS_CONFIG_FILE)
28 #include "mbedtls/config.h"
29 #else
30 #include MBEDTLS_CONFIG_FILE
31 #endif
32
33 #if defined(MBEDTLS_X509_CSR_WRITE_C)
34
35 #include "mbedtls/x509_csr.h"
36 #include "mbedtls/oid.h"
37 #include "mbedtls/asn1write.h"
38 #include "mbedtls/platform_util.h"
39
40 #include <string.h>
41 #include <stdlib.h>
42
43 #if defined(MBEDTLS_PEM_WRITE_C)
44 #include "mbedtls/pem.h"
45 #endif
46
mbedtls_x509write_csr_init(mbedtls_x509write_csr * ctx)47 void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx )
48 {
49 memset( ctx, 0, sizeof( mbedtls_x509write_csr ) );
50 }
51
mbedtls_x509write_csr_free(mbedtls_x509write_csr * ctx)52 void mbedtls_x509write_csr_free( mbedtls_x509write_csr *ctx )
53 {
54 mbedtls_asn1_free_named_data_list( &ctx->subject );
55 mbedtls_asn1_free_named_data_list( &ctx->extensions );
56
57 mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x509write_csr ) );
58 }
59
mbedtls_x509write_csr_set_md_alg(mbedtls_x509write_csr * ctx,mbedtls_md_type_t md_alg)60 void mbedtls_x509write_csr_set_md_alg( mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg )
61 {
62 ctx->md_alg = md_alg;
63 }
64
mbedtls_x509write_csr_set_key(mbedtls_x509write_csr * ctx,mbedtls_pk_context * key)65 void mbedtls_x509write_csr_set_key( mbedtls_x509write_csr *ctx, mbedtls_pk_context *key )
66 {
67 ctx->key = key;
68 }
69
mbedtls_x509write_csr_set_subject_name(mbedtls_x509write_csr * ctx,const char * subject_name)70 int mbedtls_x509write_csr_set_subject_name( mbedtls_x509write_csr *ctx,
71 const char *subject_name )
72 {
73 return mbedtls_x509_string_to_names( &ctx->subject, subject_name );
74 }
75
mbedtls_x509write_csr_set_extension(mbedtls_x509write_csr * ctx,const char * oid,size_t oid_len,const unsigned char * val,size_t val_len)76 int mbedtls_x509write_csr_set_extension( mbedtls_x509write_csr *ctx,
77 const char *oid, size_t oid_len,
78 const unsigned char *val, size_t val_len )
79 {
80 return mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len,
81 0, val, val_len );
82 }
83
mbedtls_x509write_csr_set_key_usage(mbedtls_x509write_csr * ctx,unsigned char key_usage)84 int mbedtls_x509write_csr_set_key_usage( mbedtls_x509write_csr *ctx, unsigned char key_usage )
85 {
86 unsigned char buf[4];
87 unsigned char *c;
88 int ret;
89
90 c = buf + 4;
91
92 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &key_usage, 7 ) ) != 4 )
93 return( ret );
94
95 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_KEY_USAGE,
96 MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ),
97 buf, 4 );
98 if( ret != 0 )
99 return( ret );
100
101 return( 0 );
102 }
103
mbedtls_x509write_csr_set_ns_cert_type(mbedtls_x509write_csr * ctx,unsigned char ns_cert_type)104 int mbedtls_x509write_csr_set_ns_cert_type( mbedtls_x509write_csr *ctx,
105 unsigned char ns_cert_type )
106 {
107 unsigned char buf[4];
108 unsigned char *c;
109 int ret;
110
111 c = buf + 4;
112
113 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &ns_cert_type, 8 ) ) != 4 )
114 return( ret );
115
116 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE,
117 MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ),
118 buf, 4 );
119 if( ret != 0 )
120 return( ret );
121
122 return( 0 );
123 }
124
mbedtls_x509write_csr_der(mbedtls_x509write_csr * ctx,unsigned char * buf,size_t size,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)125 int mbedtls_x509write_csr_der( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size,
126 int (*f_rng)(void *, unsigned char *, size_t),
127 void *p_rng )
128 {
129 int ret;
130 const char *sig_oid;
131 size_t sig_oid_len = 0;
132 unsigned char *c, *c2;
133 unsigned char hash[64];
134 unsigned char sig[MBEDTLS_MPI_MAX_SIZE];
135 unsigned char tmp_buf[2048];
136 size_t pub_len = 0, sig_and_oid_len = 0, sig_len;
137 size_t len = 0;
138 mbedtls_pk_type_t pk_alg;
139
140 /*
141 * Prepare data to be signed in tmp_buf
142 */
143 c = tmp_buf + sizeof( tmp_buf );
144
145 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) );
146
147 if( len )
148 {
149 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
150 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
151 MBEDTLS_ASN1_SEQUENCE ) );
152
153 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
154 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
155 MBEDTLS_ASN1_SET ) );
156
157 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( &c, tmp_buf, MBEDTLS_OID_PKCS9_CSR_EXT_REQ,
158 MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS9_CSR_EXT_REQ ) ) );
159
160 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
161 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
162 MBEDTLS_ASN1_SEQUENCE ) );
163 }
164
165 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
166 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
167 MBEDTLS_ASN1_CONTEXT_SPECIFIC ) );
168
169 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->key,
170 tmp_buf, c - tmp_buf ) );
171 c -= pub_len;
172 len += pub_len;
173
174 /*
175 * Subject ::= Name
176 */
177 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->subject ) );
178
179 /*
180 * Version ::= INTEGER { v1(0), v2(1), v3(2) }
181 */
182 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, tmp_buf, 0 ) );
183
184 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
185 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
186 MBEDTLS_ASN1_SEQUENCE ) );
187
188 /*
189 * Prepare signature
190 */
191 mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash );
192
193 if( ( ret = mbedtls_pk_sign( ctx->key, ctx->md_alg, hash, 0, sig, &sig_len,
194 f_rng, p_rng ) ) != 0 )
195 {
196 return( ret );
197 }
198
199 if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_RSA ) )
200 pk_alg = MBEDTLS_PK_RSA;
201 else if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_ECDSA ) )
202 pk_alg = MBEDTLS_PK_ECDSA;
203 else
204 return( MBEDTLS_ERR_X509_INVALID_ALG );
205
206 if( ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,
207 &sig_oid, &sig_oid_len ) ) != 0 )
208 {
209 return( ret );
210 }
211
212 /*
213 * Write data to output buffer
214 */
215 c2 = buf + size;
216 MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, buf,
217 sig_oid, sig_oid_len, sig, sig_len ) );
218
219 if( len > (size_t)( c2 - buf ) )
220 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
221
222 c2 -= len;
223 memcpy( c2, c, len );
224
225 len += sig_and_oid_len;
226 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) );
227 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c2, buf, MBEDTLS_ASN1_CONSTRUCTED |
228 MBEDTLS_ASN1_SEQUENCE ) );
229
230 return( (int) len );
231 }
232
233 #define PEM_BEGIN_CSR "-----BEGIN CERTIFICATE REQUEST-----\n"
234 #define PEM_END_CSR "-----END CERTIFICATE REQUEST-----\n"
235
236 #if defined(MBEDTLS_PEM_WRITE_C)
mbedtls_x509write_csr_pem(mbedtls_x509write_csr * ctx,unsigned char * buf,size_t size,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)237 int mbedtls_x509write_csr_pem( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size,
238 int (*f_rng)(void *, unsigned char *, size_t),
239 void *p_rng )
240 {
241 int ret;
242 unsigned char output_buf[4096];
243 size_t olen = 0;
244
245 if( ( ret = mbedtls_x509write_csr_der( ctx, output_buf, sizeof(output_buf),
246 f_rng, p_rng ) ) < 0 )
247 {
248 return( ret );
249 }
250
251 if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR,
252 output_buf + sizeof(output_buf) - ret,
253 ret, buf, size, &olen ) ) != 0 )
254 {
255 return( ret );
256 }
257
258 return( 0 );
259 }
260 #endif /* MBEDTLS_PEM_WRITE_C */
261
262 #endif /* MBEDTLS_X509_CSR_WRITE_C */
263