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
43 #include <string.h>
44
45 #if defined(MBEDTLS_PEM_PARSE_C)
46 #include "mbedtls/pem.h"
47 #endif
48
49 #if defined(MBEDTLS_PLATFORM_C)
50 #include "mbedtls/platform.h"
51 #else
52 #include <stdlib.h>
53 #include <stdio.h>
54 #define mbedtls_free free
55 #define mbedtls_calloc calloc
56 #define mbedtls_snprintf snprintf
57 #endif
58
59 #if defined(MBEDTLS_FS_IO) || defined(EFIX64) || defined(EFI32)
60 #include <stdio.h>
61 #endif
62
63 /* Implementation that should never be optimized out by the compiler */
mbedtls_zeroize(void * v,size_t n)64 static void mbedtls_zeroize( void *v, size_t n ) {
65 volatile unsigned char *p = v; while( n-- ) *p++ = 0;
66 }
67
68 /*
69 * Version ::= INTEGER { v1(0) }
70 */
x509_csr_get_version(unsigned char ** p,const unsigned char * end,int * ver)71 static int x509_csr_get_version( unsigned char **p,
72 const unsigned char *end,
73 int *ver )
74 {
75 int ret;
76
77 if( ( ret = mbedtls_asn1_get_int( p, end, ver ) ) != 0 )
78 {
79 if( ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )
80 {
81 *ver = 0;
82 return( 0 );
83 }
84
85 return( MBEDTLS_ERR_X509_INVALID_VERSION + ret );
86 }
87
88 return( 0 );
89 }
90
91 /*
92 * Parse a CSR in DER format
93 */
mbedtls_x509_csr_parse_der(mbedtls_x509_csr * csr,const unsigned char * buf,size_t buflen)94 int mbedtls_x509_csr_parse_der( mbedtls_x509_csr *csr,
95 const unsigned char *buf, size_t buflen )
96 {
97 int ret;
98 size_t len;
99 unsigned char *p, *end;
100 mbedtls_x509_buf sig_params;
101
102 memset( &sig_params, 0, sizeof( mbedtls_x509_buf ) );
103
104 /*
105 * Check for valid input
106 */
107 if( csr == NULL || buf == NULL || buflen == 0 )
108 return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
109
110 mbedtls_x509_csr_init( csr );
111
112 /*
113 * first copy the raw DER data
114 */
115 p = mbedtls_calloc( 1, len = buflen );
116
117 if( p == NULL )
118 return( MBEDTLS_ERR_X509_ALLOC_FAILED );
119
120 memcpy( p, buf, buflen );
121
122 csr->raw.p = p;
123 csr->raw.len = len;
124 end = p + len;
125
126 /*
127 * CertificationRequest ::= SEQUENCE {
128 * certificationRequestInfo CertificationRequestInfo,
129 * signatureAlgorithm AlgorithmIdentifier,
130 * signature BIT STRING
131 * }
132 */
133 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
134 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
135 {
136 mbedtls_x509_csr_free( csr );
137 return( MBEDTLS_ERR_X509_INVALID_FORMAT );
138 }
139
140 if( len != (size_t) ( end - p ) )
141 {
142 mbedtls_x509_csr_free( csr );
143 return( MBEDTLS_ERR_X509_INVALID_FORMAT +
144 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
145 }
146
147 /*
148 * CertificationRequestInfo ::= SEQUENCE {
149 */
150 csr->cri.p = p;
151
152 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
153 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
154 {
155 mbedtls_x509_csr_free( csr );
156 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret );
157 }
158
159 end = p + len;
160 csr->cri.len = end - csr->cri.p;
161
162 /*
163 * Version ::= INTEGER { v1(0) }
164 */
165 if( ( ret = x509_csr_get_version( &p, end, &csr->version ) ) != 0 )
166 {
167 mbedtls_x509_csr_free( csr );
168 return( ret );
169 }
170
171 csr->version++;
172
173 if( csr->version != 1 )
174 {
175 mbedtls_x509_csr_free( csr );
176 return( MBEDTLS_ERR_X509_UNKNOWN_VERSION );
177 }
178
179 /*
180 * subject Name
181 */
182 csr->subject_raw.p = p;
183
184 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
185 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
186 {
187 mbedtls_x509_csr_free( csr );
188 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret );
189 }
190
191 if( ( ret = mbedtls_x509_get_name( &p, p + len, &csr->subject ) ) != 0 )
192 {
193 mbedtls_x509_csr_free( csr );
194 return( ret );
195 }
196
197 csr->subject_raw.len = p - csr->subject_raw.p;
198
199 /*
200 * subjectPKInfo SubjectPublicKeyInfo
201 */
202 if( ( ret = mbedtls_pk_parse_subpubkey( &p, end, &csr->pk ) ) != 0 )
203 {
204 mbedtls_x509_csr_free( csr );
205 return( ret );
206 }
207
208 /*
209 * attributes [0] Attributes
210 *
211 * The list of possible attributes is open-ended, though RFC 2985
212 * (PKCS#9) defines a few in section 5.4. We currently don't support any,
213 * so we just ignore them. This is a safe thing to do as the worst thing
214 * that could happen is that we issue a certificate that does not match
215 * the requester's expectations - this cannot cause a violation of our
216 * signature policies.
217 */
218 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
219 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC ) ) != 0 )
220 {
221 mbedtls_x509_csr_free( csr );
222 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret );
223 }
224
225 p += len;
226
227 end = csr->raw.p + csr->raw.len;
228
229 /*
230 * signatureAlgorithm AlgorithmIdentifier,
231 * signature BIT STRING
232 */
233 if( ( ret = mbedtls_x509_get_alg( &p, end, &csr->sig_oid, &sig_params ) ) != 0 )
234 {
235 mbedtls_x509_csr_free( csr );
236 return( ret );
237 }
238
239 if( ( ret = mbedtls_x509_get_sig_alg( &csr->sig_oid, &sig_params,
240 &csr->sig_md, &csr->sig_pk,
241 &csr->sig_opts ) ) != 0 )
242 {
243 mbedtls_x509_csr_free( csr );
244 return( MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG );
245 }
246
247 if( ( ret = mbedtls_x509_get_sig( &p, end, &csr->sig ) ) != 0 )
248 {
249 mbedtls_x509_csr_free( csr );
250 return( ret );
251 }
252
253 if( p != end )
254 {
255 mbedtls_x509_csr_free( csr );
256 return( MBEDTLS_ERR_X509_INVALID_FORMAT +
257 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
258 }
259
260 return( 0 );
261 }
262
263 /*
264 * Parse a CSR, allowing for PEM or raw DER encoding
265 */
mbedtls_x509_csr_parse(mbedtls_x509_csr * csr,const unsigned char * buf,size_t buflen)266 int mbedtls_x509_csr_parse( mbedtls_x509_csr *csr, const unsigned char *buf, size_t buflen )
267 {
268 int ret;
269 #if defined(MBEDTLS_PEM_PARSE_C)
270 size_t use_len;
271 mbedtls_pem_context pem;
272 #endif
273
274 /*
275 * Check for valid input
276 */
277 if( csr == NULL || buf == NULL || buflen == 0 )
278 return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
279
280 #if defined(MBEDTLS_PEM_PARSE_C)
281 mbedtls_pem_init( &pem );
282
283 /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
284 if( buf[buflen - 1] != '\0' )
285 ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
286 else
287 ret = mbedtls_pem_read_buffer( &pem,
288 "-----BEGIN CERTIFICATE REQUEST-----",
289 "-----END CERTIFICATE REQUEST-----",
290 buf, NULL, 0, &use_len );
291
292 if( ret == 0 )
293 {
294 /*
295 * Was PEM encoded, parse the result
296 */
297 if( ( ret = mbedtls_x509_csr_parse_der( csr, pem.buf, pem.buflen ) ) != 0 )
298 return( ret );
299
300 mbedtls_pem_free( &pem );
301 return( 0 );
302 }
303 else if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
304 {
305 mbedtls_pem_free( &pem );
306 return( ret );
307 }
308 else
309 #endif /* MBEDTLS_PEM_PARSE_C */
310 return( mbedtls_x509_csr_parse_der( csr, buf, buflen ) );
311 }
312
313 #if defined(MBEDTLS_FS_IO)
314 /*
315 * Load a CSR into the structure
316 */
mbedtls_x509_csr_parse_file(mbedtls_x509_csr * csr,const char * path)317 int mbedtls_x509_csr_parse_file( mbedtls_x509_csr *csr, const char *path )
318 {
319 int ret;
320 size_t n;
321 unsigned char *buf;
322
323 if( ( ret = mbedtls_pk_load_file( path, &buf, &n ) ) != 0 )
324 return( ret );
325
326 ret = mbedtls_x509_csr_parse( csr, buf, n );
327
328 mbedtls_zeroize( buf, n );
329 mbedtls_free( buf );
330
331 return( ret );
332 }
333 #endif /* MBEDTLS_FS_IO */
334
335 #define BEFORE_COLON 14
336 #define BC "14"
337 /*
338 * Return an informational string about the CSR.
339 */
mbedtls_x509_csr_info(char * buf,size_t size,const char * prefix,const mbedtls_x509_csr * csr)340 int mbedtls_x509_csr_info( char *buf, size_t size, const char *prefix,
341 const mbedtls_x509_csr *csr )
342 {
343 int ret;
344 size_t n;
345 char *p;
346 char key_size_str[BEFORE_COLON];
347
348 p = buf;
349 n = size;
350
351 ret = mbedtls_snprintf( p, n, "%sCSR version : %d",
352 prefix, csr->version );
353 MBEDTLS_X509_SAFE_SNPRINTF;
354
355 ret = mbedtls_snprintf( p, n, "\n%ssubject name : ", prefix );
356 MBEDTLS_X509_SAFE_SNPRINTF;
357 ret = mbedtls_x509_dn_gets( p, n, &csr->subject );
358 MBEDTLS_X509_SAFE_SNPRINTF;
359
360 ret = mbedtls_snprintf( p, n, "\n%ssigned using : ", prefix );
361 MBEDTLS_X509_SAFE_SNPRINTF;
362
363 ret = mbedtls_x509_sig_alg_gets( p, n, &csr->sig_oid, csr->sig_pk, csr->sig_md,
364 csr->sig_opts );
365 MBEDTLS_X509_SAFE_SNPRINTF;
366
367 if( ( ret = mbedtls_x509_key_size_helper( key_size_str, BEFORE_COLON,
368 mbedtls_pk_get_name( &csr->pk ) ) ) != 0 )
369 {
370 return( ret );
371 }
372
373 ret = mbedtls_snprintf( p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str,
374 (int) mbedtls_pk_get_bitlen( &csr->pk ) );
375 MBEDTLS_X509_SAFE_SNPRINTF;
376
377 return( (int) ( size - n ) );
378 }
379
380 /*
381 * Initialize a CSR
382 */
mbedtls_x509_csr_init(mbedtls_x509_csr * csr)383 void mbedtls_x509_csr_init( mbedtls_x509_csr *csr )
384 {
385 memset( csr, 0, sizeof(mbedtls_x509_csr) );
386 }
387
388 /*
389 * Unallocate all CSR data
390 */
mbedtls_x509_csr_free(mbedtls_x509_csr * csr)391 void mbedtls_x509_csr_free( mbedtls_x509_csr *csr )
392 {
393 mbedtls_x509_name *name_cur;
394 mbedtls_x509_name *name_prv;
395
396 if( csr == NULL )
397 return;
398
399 mbedtls_pk_free( &csr->pk );
400
401 #if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
402 mbedtls_free( csr->sig_opts );
403 #endif
404
405 name_cur = csr->subject.next;
406 while( name_cur != NULL )
407 {
408 name_prv = name_cur;
409 name_cur = name_cur->next;
410 mbedtls_zeroize( name_prv, sizeof( mbedtls_x509_name ) );
411 mbedtls_free( name_prv );
412 }
413
414 if( csr->raw.p != NULL )
415 {
416 mbedtls_zeroize( csr->raw.p, csr->raw.len );
417 mbedtls_free( csr->raw.p );
418 }
419
420 mbedtls_zeroize( csr, sizeof( mbedtls_x509_csr ) );
421 }
422
423 #endif /* MBEDTLS_X509_CSR_PARSE_C */
424
