1 /*
2 * X.509 base functions for creating certificates / CSRs
3 *
4 * Copyright The Mbed TLS Contributors
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
20 #include "common.h"
21
22 #if defined(MBEDTLS_X509_CREATE_C)
23
24 #include "mbedtls/x509.h"
25 #include "mbedtls/asn1write.h"
26 #include "mbedtls/error.h"
27 #include "mbedtls/oid.h"
28
29 #include <string.h>
30
31 /* Structure linking OIDs for X.509 DN AttributeTypes to their
32 * string representations and default string encodings used by Mbed TLS. */
33 typedef struct {
34 const char *name; /* String representation of AttributeType, e.g.
35 * "CN" or "emailAddress". */
36 size_t name_len; /* Length of 'name', without trailing 0 byte. */
37 const char *oid; /* String representation of OID of AttributeType,
38 * as per RFC 5280, Appendix A.1. */
39 int default_tag; /* The default character encoding used for the
40 * given attribute type, e.g.
41 * MBEDTLS_ASN1_UTF8_STRING for UTF-8. */
42 } x509_attr_descriptor_t;
43
44 #define ADD_STRLEN(s) s, sizeof(s) - 1
45
46 /* X.509 DN attributes from RFC 5280, Appendix A.1. */
47 static const x509_attr_descriptor_t x509_attrs[] =
48 {
49 { ADD_STRLEN("CN"),
50 MBEDTLS_OID_AT_CN, MBEDTLS_ASN1_UTF8_STRING },
51 { ADD_STRLEN("commonName"),
52 MBEDTLS_OID_AT_CN, MBEDTLS_ASN1_UTF8_STRING },
53 { ADD_STRLEN("C"),
54 MBEDTLS_OID_AT_COUNTRY, MBEDTLS_ASN1_PRINTABLE_STRING },
55 { ADD_STRLEN("countryName"),
56 MBEDTLS_OID_AT_COUNTRY, MBEDTLS_ASN1_PRINTABLE_STRING },
57 { ADD_STRLEN("O"),
58 MBEDTLS_OID_AT_ORGANIZATION, MBEDTLS_ASN1_UTF8_STRING },
59 { ADD_STRLEN("organizationName"),
60 MBEDTLS_OID_AT_ORGANIZATION, MBEDTLS_ASN1_UTF8_STRING },
61 { ADD_STRLEN("L"),
62 MBEDTLS_OID_AT_LOCALITY, MBEDTLS_ASN1_UTF8_STRING },
63 { ADD_STRLEN("locality"),
64 MBEDTLS_OID_AT_LOCALITY, MBEDTLS_ASN1_UTF8_STRING },
65 { ADD_STRLEN("R"),
66 MBEDTLS_OID_PKCS9_EMAIL, MBEDTLS_ASN1_IA5_STRING },
67 { ADD_STRLEN("OU"),
68 MBEDTLS_OID_AT_ORG_UNIT, MBEDTLS_ASN1_UTF8_STRING },
69 { ADD_STRLEN("organizationalUnitName"),
70 MBEDTLS_OID_AT_ORG_UNIT, MBEDTLS_ASN1_UTF8_STRING },
71 { ADD_STRLEN("ST"),
72 MBEDTLS_OID_AT_STATE, MBEDTLS_ASN1_UTF8_STRING },
73 { ADD_STRLEN("stateOrProvinceName"),
74 MBEDTLS_OID_AT_STATE, MBEDTLS_ASN1_UTF8_STRING },
75 { ADD_STRLEN("emailAddress"),
76 MBEDTLS_OID_PKCS9_EMAIL, MBEDTLS_ASN1_IA5_STRING },
77 { ADD_STRLEN("serialNumber"),
78 MBEDTLS_OID_AT_SERIAL_NUMBER, MBEDTLS_ASN1_PRINTABLE_STRING },
79 { ADD_STRLEN("postalAddress"),
80 MBEDTLS_OID_AT_POSTAL_ADDRESS, MBEDTLS_ASN1_PRINTABLE_STRING },
81 { ADD_STRLEN("postalCode"),
82 MBEDTLS_OID_AT_POSTAL_CODE, MBEDTLS_ASN1_PRINTABLE_STRING },
83 { ADD_STRLEN("dnQualifier"),
84 MBEDTLS_OID_AT_DN_QUALIFIER, MBEDTLS_ASN1_PRINTABLE_STRING },
85 { ADD_STRLEN("title"),
86 MBEDTLS_OID_AT_TITLE, MBEDTLS_ASN1_UTF8_STRING },
87 { ADD_STRLEN("surName"),
88 MBEDTLS_OID_AT_SUR_NAME, MBEDTLS_ASN1_UTF8_STRING },
89 { ADD_STRLEN("SN"),
90 MBEDTLS_OID_AT_SUR_NAME, MBEDTLS_ASN1_UTF8_STRING },
91 { ADD_STRLEN("givenName"),
92 MBEDTLS_OID_AT_GIVEN_NAME, MBEDTLS_ASN1_UTF8_STRING },
93 { ADD_STRLEN("GN"),
94 MBEDTLS_OID_AT_GIVEN_NAME, MBEDTLS_ASN1_UTF8_STRING },
95 { ADD_STRLEN("initials"),
96 MBEDTLS_OID_AT_INITIALS, MBEDTLS_ASN1_UTF8_STRING },
97 { ADD_STRLEN("pseudonym"),
98 MBEDTLS_OID_AT_PSEUDONYM, MBEDTLS_ASN1_UTF8_STRING },
99 { ADD_STRLEN("generationQualifier"),
100 MBEDTLS_OID_AT_GENERATION_QUALIFIER, MBEDTLS_ASN1_UTF8_STRING },
101 { ADD_STRLEN("domainComponent"),
102 MBEDTLS_OID_DOMAIN_COMPONENT, MBEDTLS_ASN1_IA5_STRING },
103 { ADD_STRLEN("DC"),
104 MBEDTLS_OID_DOMAIN_COMPONENT, MBEDTLS_ASN1_IA5_STRING },
105 { NULL, 0, NULL, MBEDTLS_ASN1_NULL }
106 };
107
x509_attr_descr_from_name(const char * name,size_t name_len)108 static const x509_attr_descriptor_t *x509_attr_descr_from_name(const char *name, size_t name_len)
109 {
110 const x509_attr_descriptor_t *cur;
111
112 for (cur = x509_attrs; cur->name != NULL; cur++) {
113 if (cur->name_len == name_len &&
114 strncmp(cur->name, name, name_len) == 0) {
115 break;
116 }
117 }
118
119 if (cur->name == NULL) {
120 return NULL;
121 }
122
123 return cur;
124 }
125
mbedtls_x509_string_to_names(mbedtls_asn1_named_data ** head,const char * name)126 int mbedtls_x509_string_to_names(mbedtls_asn1_named_data **head, const char *name)
127 {
128 int ret = 0;
129 const char *s = name, *c = s;
130 const char *end = s + strlen(s);
131 const char *oid = NULL;
132 const x509_attr_descriptor_t *attr_descr = NULL;
133 int in_tag = 1;
134 char data[MBEDTLS_X509_MAX_DN_NAME_SIZE];
135 char *d = data;
136
137 /* Clear existing chain if present */
138 mbedtls_asn1_free_named_data_list(head);
139
140 while (c <= end) {
141 if (in_tag && *c == '=') {
142 if ((attr_descr = x509_attr_descr_from_name(s, c - s)) == NULL) {
143 ret = MBEDTLS_ERR_X509_UNKNOWN_OID;
144 goto exit;
145 }
146
147 oid = attr_descr->oid;
148 s = c + 1;
149 in_tag = 0;
150 d = data;
151 }
152
153 if (!in_tag && *c == '\\' && c != end) {
154 c++;
155
156 /* Check for valid escaped characters */
157 if (c == end || *c != ',') {
158 ret = MBEDTLS_ERR_X509_INVALID_NAME;
159 goto exit;
160 }
161 } else if (!in_tag && (*c == ',' || c == end)) {
162 mbedtls_asn1_named_data *cur =
163 mbedtls_asn1_store_named_data(head, oid, strlen(oid),
164 (unsigned char *) data,
165 d - data);
166
167 if (cur == NULL) {
168 return MBEDTLS_ERR_X509_ALLOC_FAILED;
169 }
170
171 // set tagType
172 cur->val.tag = attr_descr->default_tag;
173
174 while (c < end && *(c + 1) == ' ') {
175 c++;
176 }
177
178 s = c + 1;
179 in_tag = 1;
180 }
181
182 if (!in_tag && s != c + 1) {
183 *(d++) = *c;
184
185 if (d - data == MBEDTLS_X509_MAX_DN_NAME_SIZE) {
186 ret = MBEDTLS_ERR_X509_INVALID_NAME;
187 goto exit;
188 }
189 }
190
191 c++;
192 }
193
194 exit:
195
196 return ret;
197 }
198
199 /* The first byte of the value in the mbedtls_asn1_named_data structure is reserved
200 * to store the critical boolean for us
201 */
mbedtls_x509_set_extension(mbedtls_asn1_named_data ** head,const char * oid,size_t oid_len,int critical,const unsigned char * val,size_t val_len)202 int mbedtls_x509_set_extension(mbedtls_asn1_named_data **head, const char *oid, size_t oid_len,
203 int critical, const unsigned char *val, size_t val_len)
204 {
205 mbedtls_asn1_named_data *cur;
206
207 if ((cur = mbedtls_asn1_store_named_data(head, oid, oid_len,
208 NULL, val_len + 1)) == NULL) {
209 return MBEDTLS_ERR_X509_ALLOC_FAILED;
210 }
211
212 cur->val.p[0] = critical;
213 memcpy(cur->val.p + 1, val, val_len);
214
215 return 0;
216 }
217
218 /*
219 * RelativeDistinguishedName ::=
220 * SET OF AttributeTypeAndValue
221 *
222 * AttributeTypeAndValue ::= SEQUENCE {
223 * type AttributeType,
224 * value AttributeValue }
225 *
226 * AttributeType ::= OBJECT IDENTIFIER
227 *
228 * AttributeValue ::= ANY DEFINED BY AttributeType
229 */
x509_write_name(unsigned char ** p,unsigned char * start,mbedtls_asn1_named_data * cur_name)230 static int x509_write_name(unsigned char **p,
231 unsigned char *start,
232 mbedtls_asn1_named_data *cur_name)
233 {
234 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
235 size_t len = 0;
236 const char *oid = (const char *) cur_name->oid.p;
237 size_t oid_len = cur_name->oid.len;
238 const unsigned char *name = cur_name->val.p;
239 size_t name_len = cur_name->val.len;
240
241 // Write correct string tag and value
242 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tagged_string(p, start,
243 cur_name->val.tag,
244 (const char *) name,
245 name_len));
246 // Write OID
247 //
248 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_oid(p, start, oid,
249 oid_len));
250
251 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
252 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
253 MBEDTLS_ASN1_CONSTRUCTED |
254 MBEDTLS_ASN1_SEQUENCE));
255
256 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
257 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
258 MBEDTLS_ASN1_CONSTRUCTED |
259 MBEDTLS_ASN1_SET));
260
261 return (int) len;
262 }
263
mbedtls_x509_write_names(unsigned char ** p,unsigned char * start,mbedtls_asn1_named_data * first)264 int mbedtls_x509_write_names(unsigned char **p, unsigned char *start,
265 mbedtls_asn1_named_data *first)
266 {
267 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
268 size_t len = 0;
269 mbedtls_asn1_named_data *cur = first;
270
271 while (cur != NULL) {
272 MBEDTLS_ASN1_CHK_ADD(len, x509_write_name(p, start, cur));
273 cur = cur->next;
274 }
275
276 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
277 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED |
278 MBEDTLS_ASN1_SEQUENCE));
279
280 return (int) len;
281 }
282
mbedtls_x509_write_sig(unsigned char ** p,unsigned char * start,const char * oid,size_t oid_len,unsigned char * sig,size_t size)283 int mbedtls_x509_write_sig(unsigned char **p, unsigned char *start,
284 const char *oid, size_t oid_len,
285 unsigned char *sig, size_t size)
286 {
287 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
288 size_t len = 0;
289
290 if (*p < start || (size_t) (*p - start) < size) {
291 return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
292 }
293
294 len = size;
295 (*p) -= len;
296 memcpy(*p, sig, len);
297
298 if (*p - start < 1) {
299 return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
300 }
301
302 *--(*p) = 0;
303 len += 1;
304
305 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
306 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_BIT_STRING));
307
308 // Write OID
309 //
310 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_algorithm_identifier(p, start, oid,
311 oid_len, 0));
312
313 return (int) len;
314 }
315
x509_write_extension(unsigned char ** p,unsigned char * start,mbedtls_asn1_named_data * ext)316 static int x509_write_extension(unsigned char **p, unsigned char *start,
317 mbedtls_asn1_named_data *ext)
318 {
319 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
320 size_t len = 0;
321
322 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, ext->val.p + 1,
323 ext->val.len - 1));
324 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, ext->val.len - 1));
325 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OCTET_STRING));
326
327 if (ext->val.p[0] != 0) {
328 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_bool(p, start, 1));
329 }
330
331 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, ext->oid.p,
332 ext->oid.len));
333 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, ext->oid.len));
334 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OID));
335
336 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
337 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED |
338 MBEDTLS_ASN1_SEQUENCE));
339
340 return (int) len;
341 }
342
343 /*
344 * Extension ::= SEQUENCE {
345 * extnID OBJECT IDENTIFIER,
346 * critical BOOLEAN DEFAULT FALSE,
347 * extnValue OCTET STRING
348 * -- contains the DER encoding of an ASN.1 value
349 * -- corresponding to the extension type identified
350 * -- by extnID
351 * }
352 */
mbedtls_x509_write_extensions(unsigned char ** p,unsigned char * start,mbedtls_asn1_named_data * first)353 int mbedtls_x509_write_extensions(unsigned char **p, unsigned char *start,
354 mbedtls_asn1_named_data *first)
355 {
356 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
357 size_t len = 0;
358 mbedtls_asn1_named_data *cur_ext = first;
359
360 while (cur_ext != NULL) {
361 MBEDTLS_ASN1_CHK_ADD(len, x509_write_extension(p, start, cur_ext));
362 cur_ext = cur_ext->next;
363 }
364
365 return (int) len;
366 }
367
368 #endif /* MBEDTLS_X509_CREATE_C */
369