1 /*
2 * X.509 Certificate Signing Request (CSR) parsing
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 * The ITU-T X.509 standard defines a certificate format for PKI.
23 *
24 * http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs)
25 * http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs)
26 * http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10)
27 *
28 * http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf
29 * http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
30 */
31
32 #if !defined(MBEDTLS_CONFIG_FILE)
33 #include "mbedtls/config.h"
34 #else
35 #include MBEDTLS_CONFIG_FILE
36 #endif
37
38 #if defined(MBEDTLS_X509_CSR_PARSE_C)
39
40 #include "mbedtls/x509_csr.h"
41 #include "mbedtls/oid.h"
42 #include "mbedtls/platform_util.h"
43
44 #include <string.h>
45
46 #if defined(MBEDTLS_PEM_PARSE_C)
47 #include "mbedtls/pem.h"
48 #endif
49
50 #if defined(MBEDTLS_PLATFORM_C)
51 #include "mbedtls/platform.h"
52 #else
53 #include <stdlib.h>
54 #include <stdio.h>
55 #define mbedtls_free free
56 #define mbedtls_calloc calloc
57 #define mbedtls_snprintf snprintf
58 #endif
59
60 #if defined(MBEDTLS_FS_IO) || defined(EFIX64) || defined(EFI32)
61 #include <stdio.h>
62 #endif
63
64 /*
65 * Version ::= INTEGER { v1(0) }
66 */
x509_csr_get_version(unsigned char ** p,const unsigned char * end,int * ver)67 static int x509_csr_get_version( unsigned char **p,
68 const unsigned char *end,
69 int *ver )
70 {
71 int ret;
72
73 if( ( ret = mbedtls_asn1_get_int( p, end, ver ) ) != 0 )
74 {
75 if( ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )
76 {
77 *ver = 0;
78 return( 0 );
79 }
80
81 return( MBEDTLS_ERR_X509_INVALID_VERSION + ret );
82 }
83
84 return( 0 );
85 }
86
87 /*
88 * Parse a CSR in DER format
89 */
mbedtls_x509_csr_parse_der(mbedtls_x509_csr * csr,const unsigned char * buf,size_t buflen)90 int mbedtls_x509_csr_parse_der( mbedtls_x509_csr *csr,
91 const unsigned char *buf, size_t buflen )
92 {
93 int ret;
94 size_t len;
95 unsigned char *p, *end;
96 mbedtls_x509_buf sig_params;
97
98 memset( &sig_params, 0, sizeof( mbedtls_x509_buf ) );
99
100 /*
101 * Check for valid input
102 */
103 if( csr == NULL || buf == NULL || buflen == 0 )
104 return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
105
106 mbedtls_x509_csr_init( csr );
107
108 /*
109 * first copy the raw DER data
110 */
111 p = mbedtls_calloc( 1, len = buflen );
112
113 if( p == NULL )
114 return( MBEDTLS_ERR_X509_ALLOC_FAILED );
115
116 memcpy( p, buf, buflen );
117
118 csr->raw.p = p;
119 csr->raw.len = len;
120 end = p + len;
121
122 /*
123 * CertificationRequest ::= SEQUENCE {
124 * certificationRequestInfo CertificationRequestInfo,
125 * signatureAlgorithm AlgorithmIdentifier,
126 * signature BIT STRING
127 * }
128 */
129 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
130 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
131 {
132 mbedtls_x509_csr_free( csr );
133 return( MBEDTLS_ERR_X509_INVALID_FORMAT );
134 }
135
136 if( len != (size_t) ( end - p ) )
137 {
138 mbedtls_x509_csr_free( csr );
139 return( MBEDTLS_ERR_X509_INVALID_FORMAT +
140 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
141 }
142
143 /*
144 * CertificationRequestInfo ::= SEQUENCE {
145 */
146 csr->cri.p = p;
147
148 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
149 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
150 {
151 mbedtls_x509_csr_free( csr );
152 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret );
153 }
154
155 end = p + len;
156 csr->cri.len = end - csr->cri.p;
157
158 /*
159 * Version ::= INTEGER { v1(0) }
160 */
161 if( ( ret = x509_csr_get_version( &p, end, &csr->version ) ) != 0 )
162 {
163 mbedtls_x509_csr_free( csr );
164 return( ret );
165 }
166
167 if( csr->version != 0 )
168 {
169 mbedtls_x509_csr_free( csr );
170 return( MBEDTLS_ERR_X509_UNKNOWN_VERSION );
171 }
172
173 csr->version++;
174
175 /*
176 * subject Name
177 */
178 csr->subject_raw.p = p;
179
180 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
181 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
182 {
183 mbedtls_x509_csr_free( csr );
184 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret );
185 }
186
187 if( ( ret = mbedtls_x509_get_name( &p, p + len, &csr->subject ) ) != 0 )
188 {
189 mbedtls_x509_csr_free( csr );
190 return( ret );
191 }
192
193 csr->subject_raw.len = p - csr->subject_raw.p;
194
195 /*
196 * subjectPKInfo SubjectPublicKeyInfo
197 */
198 if( ( ret = mbedtls_pk_parse_subpubkey( &p, end, &csr->pk ) ) != 0 )
199 {
200 mbedtls_x509_csr_free( csr );
201 return( ret );
202 }
203
204 /*
205 * attributes [0] Attributes
206 *
207 * The list of possible attributes is open-ended, though RFC 2985
208 * (PKCS#9) defines a few in section 5.4. We currently don't support any,
209 * so we just ignore them. This is a safe thing to do as the worst thing
210 * that could happen is that we issue a certificate that does not match
211 * the requester's expectations - this cannot cause a violation of our
212 * signature policies.
213 */
214 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
215 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC ) ) != 0 )
216 {
217 mbedtls_x509_csr_free( csr );
218 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret );
219 }
220
221 p += len;
222
223 end = csr->raw.p + csr->raw.len;
224
225 /*
226 * signatureAlgorithm AlgorithmIdentifier,
227 * signature BIT STRING
228 */
229 if( ( ret = mbedtls_x509_get_alg( &p, end, &csr->sig_oid, &sig_params ) ) != 0 )
230 {
231 mbedtls_x509_csr_free( csr );
232 return( ret );
233 }
234
235 if( ( ret = mbedtls_x509_get_sig_alg( &csr->sig_oid, &sig_params,
236 &csr->sig_md, &csr->sig_pk,
237 &csr->sig_opts ) ) != 0 )
238 {
239 mbedtls_x509_csr_free( csr );
240 return( MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG );
241 }
242
243 if( ( ret = mbedtls_x509_get_sig( &p, end, &csr->sig ) ) != 0 )
244 {
245 mbedtls_x509_csr_free( csr );
246 return( ret );
247 }
248
249 if( p != end )
250 {
251 mbedtls_x509_csr_free( csr );
252 return( MBEDTLS_ERR_X509_INVALID_FORMAT +
253 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
254 }
255
256 return( 0 );
257 }
258
259 /*
260 * Parse a CSR, allowing for PEM or raw DER encoding
261 */
mbedtls_x509_csr_parse(mbedtls_x509_csr * csr,const unsigned char * buf,size_t buflen)262 int mbedtls_x509_csr_parse( mbedtls_x509_csr *csr, const unsigned char *buf, size_t buflen )
263 {
264 #if defined(MBEDTLS_PEM_PARSE_C)
265 int ret;
266 size_t use_len;
267 mbedtls_pem_context pem;
268 #endif
269
270 /*
271 * Check for valid input
272 */
273 if( csr == NULL || buf == NULL || buflen == 0 )
274 return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
275
276 #if defined(MBEDTLS_PEM_PARSE_C)
277 /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
278 if( buf[buflen - 1] == '\0' )
279 {
280 mbedtls_pem_init( &pem );
281 ret = mbedtls_pem_read_buffer( &pem,
282 "-----BEGIN CERTIFICATE REQUEST-----",
283 "-----END CERTIFICATE REQUEST-----",
284 buf, NULL, 0, &use_len );
285
286 if( ret == 0 )
287 /*
288 * Was PEM encoded, parse the result
289 */
290 ret = mbedtls_x509_csr_parse_der( csr, pem.buf, pem.buflen );
291
292 mbedtls_pem_free( &pem );
293 if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
294 return( ret );
295 }
296 #endif /* MBEDTLS_PEM_PARSE_C */
297 return( mbedtls_x509_csr_parse_der( csr, buf, buflen ) );
298 }
299
300 #if defined(MBEDTLS_FS_IO)
301 /*
302 * Load a CSR into the structure
303 */
mbedtls_x509_csr_parse_file(mbedtls_x509_csr * csr,const char * path)304 int mbedtls_x509_csr_parse_file( mbedtls_x509_csr *csr, const char *path )
305 {
306 int ret;
307 size_t n;
308 unsigned char *buf;
309
310 if( ( ret = mbedtls_pk_load_file( path, &buf, &n ) ) != 0 )
311 return( ret );
312
313 ret = mbedtls_x509_csr_parse( csr, buf, n );
314
315 mbedtls_platform_zeroize( buf, n );
316 mbedtls_free( buf );
317
318 return( ret );
319 }
320 #endif /* MBEDTLS_FS_IO */
321
322 #define BEFORE_COLON 14
323 #define BC "14"
324 /*
325 * Return an informational string about the CSR.
326 */
mbedtls_x509_csr_info(char * buf,size_t size,const char * prefix,const mbedtls_x509_csr * csr)327 int mbedtls_x509_csr_info( char *buf, size_t size, const char *prefix,
328 const mbedtls_x509_csr *csr )
329 {
330 int ret;
331 size_t n;
332 char *p;
333 char key_size_str[BEFORE_COLON];
334
335 p = buf;
336 n = size;
337
338 ret = mbedtls_snprintf( p, n, "%sCSR version : %d",
339 prefix, csr->version );
340 MBEDTLS_X509_SAFE_SNPRINTF;
341
342 ret = mbedtls_snprintf( p, n, "\n%ssubject name : ", prefix );
343 MBEDTLS_X509_SAFE_SNPRINTF;
344 ret = mbedtls_x509_dn_gets( p, n, &csr->subject );
345 MBEDTLS_X509_SAFE_SNPRINTF;
346
347 ret = mbedtls_snprintf( p, n, "\n%ssigned using : ", prefix );
348 MBEDTLS_X509_SAFE_SNPRINTF;
349
350 ret = mbedtls_x509_sig_alg_gets( p, n, &csr->sig_oid, csr->sig_pk, csr->sig_md,
351 csr->sig_opts );
352 MBEDTLS_X509_SAFE_SNPRINTF;
353
354 if( ( ret = mbedtls_x509_key_size_helper( key_size_str, BEFORE_COLON,
355 mbedtls_pk_get_name( &csr->pk ) ) ) != 0 )
356 {
357 return( ret );
358 }
359
360 ret = mbedtls_snprintf( p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str,
361 (int) mbedtls_pk_get_bitlen( &csr->pk ) );
362 MBEDTLS_X509_SAFE_SNPRINTF;
363
364 return( (int) ( size - n ) );
365 }
366
367 /*
368 * Initialize a CSR
369 */
mbedtls_x509_csr_init(mbedtls_x509_csr * csr)370 void mbedtls_x509_csr_init( mbedtls_x509_csr *csr )
371 {
372 memset( csr, 0, sizeof(mbedtls_x509_csr) );
373 }
374
375 /*
376 * Unallocate all CSR data
377 */
mbedtls_x509_csr_free(mbedtls_x509_csr * csr)378 void mbedtls_x509_csr_free( mbedtls_x509_csr *csr )
379 {
380 mbedtls_x509_name *name_cur;
381 mbedtls_x509_name *name_prv;
382
383 if( csr == NULL )
384 return;
385
386 mbedtls_pk_free( &csr->pk );
387
388 #if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
389 mbedtls_free( csr->sig_opts );
390 #endif
391
392 name_cur = csr->subject.next;
393 while( name_cur != NULL )
394 {
395 name_prv = name_cur;
396 name_cur = name_cur->next;
397 mbedtls_platform_zeroize( name_prv, sizeof( mbedtls_x509_name ) );
398 mbedtls_free( name_prv );
399 }
400
401 if( csr->raw.p != NULL )
402 {
403 mbedtls_platform_zeroize( csr->raw.p, csr->raw.len );
404 mbedtls_free( csr->raw.p );
405 }
406
407 mbedtls_platform_zeroize( csr, sizeof( mbedtls_x509_csr ) );
408 }
409
410 #endif /* MBEDTLS_X509_CSR_PARSE_C */
411