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
39 #include <string.h>
40 #include <stdlib.h>
41
42 #if defined(MBEDTLS_PEM_WRITE_C)
43 #include "mbedtls/pem.h"
44 #endif
45
46 /* Implementation that should never be optimized out by the compiler */
mbedtls_zeroize(void * v,size_t n)47 static void mbedtls_zeroize( void *v, size_t n ) {
48 volatile unsigned char *p = v; while( n-- ) *p++ = 0;
49 }
50
mbedtls_x509write_csr_init(mbedtls_x509write_csr * ctx)51 void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx )
52 {
53 memset( ctx, 0, sizeof(mbedtls_x509write_csr) );
54 }
55
mbedtls_x509write_csr_free(mbedtls_x509write_csr * ctx)56 void mbedtls_x509write_csr_free( mbedtls_x509write_csr *ctx )
57 {
58 mbedtls_asn1_free_named_data_list( &ctx->subject );
59 mbedtls_asn1_free_named_data_list( &ctx->extensions );
60
61 mbedtls_zeroize( ctx, sizeof(mbedtls_x509write_csr) );
62 }
63
mbedtls_x509write_csr_set_md_alg(mbedtls_x509write_csr * ctx,mbedtls_md_type_t md_alg)64 void mbedtls_x509write_csr_set_md_alg( mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg )
65 {
66 ctx->md_alg = md_alg;
67 }
68
mbedtls_x509write_csr_set_key(mbedtls_x509write_csr * ctx,mbedtls_pk_context * key)69 void mbedtls_x509write_csr_set_key( mbedtls_x509write_csr *ctx, mbedtls_pk_context *key )
70 {
71 ctx->key = key;
72 }
73
mbedtls_x509write_csr_set_subject_name(mbedtls_x509write_csr * ctx,const char * subject_name)74 int mbedtls_x509write_csr_set_subject_name( mbedtls_x509write_csr *ctx,
75 const char *subject_name )
76 {
77 return mbedtls_x509_string_to_names( &ctx->subject, subject_name );
78 }
79
mbedtls_x509write_csr_set_extension(mbedtls_x509write_csr * ctx,const char * oid,size_t oid_len,const unsigned char * val,size_t val_len)80 int mbedtls_x509write_csr_set_extension( mbedtls_x509write_csr *ctx,
81 const char *oid, size_t oid_len,
82 const unsigned char *val, size_t val_len )
83 {
84 return mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len,
85 0, val, val_len );
86 }
87
mbedtls_x509write_csr_set_key_usage(mbedtls_x509write_csr * ctx,unsigned char key_usage)88 int mbedtls_x509write_csr_set_key_usage( mbedtls_x509write_csr *ctx, unsigned char key_usage )
89 {
90 unsigned char buf[4];
91 unsigned char *c;
92 int ret;
93
94 c = buf + 4;
95
96 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &key_usage, 7 ) ) != 4 )
97 return( ret );
98
99 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_KEY_USAGE,
100 MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ),
101 buf, 4 );
102 if( ret != 0 )
103 return( ret );
104
105 return( 0 );
106 }
107
mbedtls_x509write_csr_set_ns_cert_type(mbedtls_x509write_csr * ctx,unsigned char ns_cert_type)108 int mbedtls_x509write_csr_set_ns_cert_type( mbedtls_x509write_csr *ctx,
109 unsigned char ns_cert_type )
110 {
111 unsigned char buf[4];
112 unsigned char *c;
113 int ret;
114
115 c = buf + 4;
116
117 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &ns_cert_type, 8 ) ) != 4 )
118 return( ret );
119
120 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE,
121 MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ),
122 buf, 4 );
123 if( ret != 0 )
124 return( ret );
125
126 return( 0 );
127 }
128
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)129 int mbedtls_x509write_csr_der( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size,
130 int (*f_rng)(void *, unsigned char *, size_t),
131 void *p_rng )
132 {
133 int ret;
134 const char *sig_oid;
135 size_t sig_oid_len = 0;
136 unsigned char *c, *c2;
137 unsigned char hash[64];
138 unsigned char sig[MBEDTLS_MPI_MAX_SIZE];
139 unsigned char tmp_buf[2048];
140 size_t pub_len = 0, sig_and_oid_len = 0, sig_len;
141 size_t len = 0;
142 mbedtls_pk_type_t pk_alg;
143
144 /*
145 * Prepare data to be signed in tmp_buf
146 */
147 c = tmp_buf + sizeof( tmp_buf );
148
149 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) );
150
151 if( len )
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_SEQUENCE ) );
156
157 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
158 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
159 MBEDTLS_ASN1_SET ) );
160
161 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( &c, tmp_buf, MBEDTLS_OID_PKCS9_CSR_EXT_REQ,
162 MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS9_CSR_EXT_REQ ) ) );
163
164 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
165 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
166 MBEDTLS_ASN1_SEQUENCE ) );
167 }
168
169 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
170 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
171 MBEDTLS_ASN1_CONTEXT_SPECIFIC ) );
172
173 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->key,
174 tmp_buf, c - tmp_buf ) );
175 c -= pub_len;
176 len += pub_len;
177
178 /*
179 * Subject ::= Name
180 */
181 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->subject ) );
182
183 /*
184 * Version ::= INTEGER { v1(0), v2(1), v3(2) }
185 */
186 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, tmp_buf, 0 ) );
187
188 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
189 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
190 MBEDTLS_ASN1_SEQUENCE ) );
191
192 /*
193 * Prepare signature
194 */
195 mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash );
196
197 pk_alg = mbedtls_pk_get_type( ctx->key );
198 if( pk_alg == MBEDTLS_PK_ECKEY )
199 pk_alg = MBEDTLS_PK_ECDSA;
200
201 if( ( ret = mbedtls_pk_sign( ctx->key, ctx->md_alg, hash, 0, sig, &sig_len,
202 f_rng, p_rng ) ) != 0 ||
203 ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,
204 &sig_oid, &sig_oid_len ) ) != 0 )
205 {
206 return( ret );
207 }
208
209 /*
210 * Write data to output buffer
211 */
212 c2 = buf + size;
213 MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, buf,
214 sig_oid, sig_oid_len, sig, sig_len ) );
215
216 if( len > (size_t)( c2 - buf ) )
217 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
218
219 c2 -= len;
220 memcpy( c2, c, len );
221
222 len += sig_and_oid_len;
223 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) );
224 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c2, buf, MBEDTLS_ASN1_CONSTRUCTED |
225 MBEDTLS_ASN1_SEQUENCE ) );
226
227 return( (int) len );
228 }
229
230 #define PEM_BEGIN_CSR "-----BEGIN CERTIFICATE REQUEST-----\n"
231 #define PEM_END_CSR "-----END CERTIFICATE REQUEST-----\n"
232
233 #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)234 int mbedtls_x509write_csr_pem( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size,
235 int (*f_rng)(void *, unsigned char *, size_t),
236 void *p_rng )
237 {
238 int ret;
239 unsigned char output_buf[4096];
240 size_t olen = 0;
241
242 if( ( ret = mbedtls_x509write_csr_der( ctx, output_buf, sizeof(output_buf),
243 f_rng, p_rng ) ) < 0 )
244 {
245 return( ret );
246 }
247
248 if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR,
249 output_buf + sizeof(output_buf) - ret,
250 ret, buf, size, &olen ) ) != 0 )
251 {
252 return( ret );
253 }
254
255 return( 0 );
256 }
257 #endif /* MBEDTLS_PEM_WRITE_C */
258
259 #endif /* MBEDTLS_X509_CSR_WRITE_C */
260
