1 /*
2 * X.509 certificate writing
3 *
4 * Copyright The Mbed TLS Contributors
5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 */
7 /*
8 * References:
9 * - certificates: RFC 5280, updated by RFC 6818
10 * - CSRs: PKCS#10 v1.7 aka RFC 2986
11 * - attributes: PKCS#9 v2.0 aka RFC 2985
12 */
13
14 #include "common.h"
15
16 #if defined(MBEDTLS_X509_CRT_WRITE_C)
17
18 #include "mbedtls/x509_crt.h"
19 #include "x509_internal.h"
20 #include "mbedtls/asn1write.h"
21 #include "mbedtls/error.h"
22 #include "mbedtls/oid.h"
23 #include "mbedtls/platform.h"
24 #include "mbedtls/platform_util.h"
25 #include "mbedtls/md.h"
26
27 #include <string.h>
28 #include <stdint.h>
29
30 #if defined(MBEDTLS_PEM_WRITE_C)
31 #include "mbedtls/pem.h"
32 #endif /* MBEDTLS_PEM_WRITE_C */
33
34 #if defined(MBEDTLS_USE_PSA_CRYPTO)
35 #include "psa/crypto.h"
36 #include "psa_util_internal.h"
37 #include "mbedtls/psa_util.h"
38 #endif /* MBEDTLS_USE_PSA_CRYPTO */
39
mbedtls_x509write_crt_init(mbedtls_x509write_cert * ctx)40 void mbedtls_x509write_crt_init(mbedtls_x509write_cert *ctx)
41 {
42 memset(ctx, 0, sizeof(mbedtls_x509write_cert));
43
44 ctx->version = MBEDTLS_X509_CRT_VERSION_3;
45 }
46
mbedtls_x509write_crt_free(mbedtls_x509write_cert * ctx)47 void mbedtls_x509write_crt_free(mbedtls_x509write_cert *ctx)
48 {
49 mbedtls_asn1_free_named_data_list(&ctx->subject);
50 mbedtls_asn1_free_named_data_list(&ctx->issuer);
51 mbedtls_asn1_free_named_data_list(&ctx->extensions);
52
53 mbedtls_platform_zeroize(ctx, sizeof(mbedtls_x509write_cert));
54 }
55
mbedtls_x509write_crt_set_version(mbedtls_x509write_cert * ctx,int version)56 void mbedtls_x509write_crt_set_version(mbedtls_x509write_cert *ctx,
57 int version)
58 {
59 ctx->version = version;
60 }
61
mbedtls_x509write_crt_set_md_alg(mbedtls_x509write_cert * ctx,mbedtls_md_type_t md_alg)62 void mbedtls_x509write_crt_set_md_alg(mbedtls_x509write_cert *ctx,
63 mbedtls_md_type_t md_alg)
64 {
65 ctx->md_alg = md_alg;
66 }
67
mbedtls_x509write_crt_set_subject_key(mbedtls_x509write_cert * ctx,mbedtls_pk_context * key)68 void mbedtls_x509write_crt_set_subject_key(mbedtls_x509write_cert *ctx,
69 mbedtls_pk_context *key)
70 {
71 ctx->subject_key = key;
72 }
73
mbedtls_x509write_crt_set_issuer_key(mbedtls_x509write_cert * ctx,mbedtls_pk_context * key)74 void mbedtls_x509write_crt_set_issuer_key(mbedtls_x509write_cert *ctx,
75 mbedtls_pk_context *key)
76 {
77 ctx->issuer_key = key;
78 }
79
mbedtls_x509write_crt_set_subject_name(mbedtls_x509write_cert * ctx,const char * subject_name)80 int mbedtls_x509write_crt_set_subject_name(mbedtls_x509write_cert *ctx,
81 const char *subject_name)
82 {
83 mbedtls_asn1_free_named_data_list(&ctx->subject);
84 return mbedtls_x509_string_to_names(&ctx->subject, subject_name);
85 }
86
mbedtls_x509write_crt_set_issuer_name(mbedtls_x509write_cert * ctx,const char * issuer_name)87 int mbedtls_x509write_crt_set_issuer_name(mbedtls_x509write_cert *ctx,
88 const char *issuer_name)
89 {
90 mbedtls_asn1_free_named_data_list(&ctx->issuer);
91 return mbedtls_x509_string_to_names(&ctx->issuer, issuer_name);
92 }
93
94 #if defined(MBEDTLS_BIGNUM_C) && !defined(MBEDTLS_DEPRECATED_REMOVED)
mbedtls_x509write_crt_set_serial(mbedtls_x509write_cert * ctx,const mbedtls_mpi * serial)95 int mbedtls_x509write_crt_set_serial(mbedtls_x509write_cert *ctx,
96 const mbedtls_mpi *serial)
97 {
98 int ret;
99 size_t tmp_len;
100
101 /* Ensure that the MPI value fits into the buffer */
102 tmp_len = mbedtls_mpi_size(serial);
103 if (tmp_len > MBEDTLS_X509_RFC5280_MAX_SERIAL_LEN) {
104 return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
105 }
106
107 ctx->serial_len = tmp_len;
108
109 ret = mbedtls_mpi_write_binary(serial, ctx->serial, tmp_len);
110 if (ret < 0) {
111 return ret;
112 }
113
114 return 0;
115 }
116 #endif // MBEDTLS_BIGNUM_C && !MBEDTLS_DEPRECATED_REMOVED
117
mbedtls_x509write_crt_set_serial_raw(mbedtls_x509write_cert * ctx,unsigned char * serial,size_t serial_len)118 int mbedtls_x509write_crt_set_serial_raw(mbedtls_x509write_cert *ctx,
119 unsigned char *serial, size_t serial_len)
120 {
121 if (serial_len > MBEDTLS_X509_RFC5280_MAX_SERIAL_LEN) {
122 return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
123 }
124
125 ctx->serial_len = serial_len;
126 memcpy(ctx->serial, serial, serial_len);
127
128 return 0;
129 }
130
mbedtls_x509write_crt_set_validity(mbedtls_x509write_cert * ctx,const char * not_before,const char * not_after)131 int mbedtls_x509write_crt_set_validity(mbedtls_x509write_cert *ctx,
132 const char *not_before,
133 const char *not_after)
134 {
135 if (strlen(not_before) != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1 ||
136 strlen(not_after) != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1) {
137 return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
138 }
139 strncpy(ctx->not_before, not_before, MBEDTLS_X509_RFC5280_UTC_TIME_LEN);
140 strncpy(ctx->not_after, not_after, MBEDTLS_X509_RFC5280_UTC_TIME_LEN);
141 ctx->not_before[MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1] = 'Z';
142 ctx->not_after[MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1] = 'Z';
143
144 return 0;
145 }
146
mbedtls_x509write_crt_set_subject_alternative_name(mbedtls_x509write_cert * ctx,const mbedtls_x509_san_list * san_list)147 int mbedtls_x509write_crt_set_subject_alternative_name(mbedtls_x509write_cert *ctx,
148 const mbedtls_x509_san_list *san_list)
149 {
150 return mbedtls_x509_write_set_san_common(&ctx->extensions, san_list);
151 }
152
153
mbedtls_x509write_crt_set_extension(mbedtls_x509write_cert * ctx,const char * oid,size_t oid_len,int critical,const unsigned char * val,size_t val_len)154 int mbedtls_x509write_crt_set_extension(mbedtls_x509write_cert *ctx,
155 const char *oid, size_t oid_len,
156 int critical,
157 const unsigned char *val, size_t val_len)
158 {
159 return mbedtls_x509_set_extension(&ctx->extensions, oid, oid_len,
160 critical, val, val_len);
161 }
162
mbedtls_x509write_crt_set_basic_constraints(mbedtls_x509write_cert * ctx,int is_ca,int max_pathlen)163 int mbedtls_x509write_crt_set_basic_constraints(mbedtls_x509write_cert *ctx,
164 int is_ca, int max_pathlen)
165 {
166 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
167 unsigned char buf[9];
168 unsigned char *c = buf + sizeof(buf);
169 size_t len = 0;
170
171 memset(buf, 0, sizeof(buf));
172
173 if (is_ca && max_pathlen > 127) {
174 return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
175 }
176
177 if (is_ca) {
178 if (max_pathlen >= 0) {
179 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(&c, buf,
180 max_pathlen));
181 }
182 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_bool(&c, buf, 1));
183 }
184
185 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
186 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf,
187 MBEDTLS_ASN1_CONSTRUCTED |
188 MBEDTLS_ASN1_SEQUENCE));
189
190 return
191 mbedtls_x509write_crt_set_extension(ctx, MBEDTLS_OID_BASIC_CONSTRAINTS,
192 MBEDTLS_OID_SIZE(MBEDTLS_OID_BASIC_CONSTRAINTS),
193 is_ca, buf + sizeof(buf) - len, len);
194 }
195
196 #if defined(MBEDTLS_MD_CAN_SHA1)
mbedtls_x509write_crt_set_key_identifier(mbedtls_x509write_cert * ctx,int is_ca,unsigned char tag)197 static int mbedtls_x509write_crt_set_key_identifier(mbedtls_x509write_cert *ctx,
198 int is_ca,
199 unsigned char tag)
200 {
201 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
202 unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20]; /* tag, length + 2xMPI */
203 unsigned char *c = buf + sizeof(buf);
204 size_t len = 0;
205 #if defined(MBEDTLS_USE_PSA_CRYPTO)
206 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
207 size_t hash_length;
208 #endif /* MBEDTLS_USE_PSA_CRYPTO */
209
210 memset(buf, 0, sizeof(buf));
211 MBEDTLS_ASN1_CHK_ADD(len,
212 mbedtls_pk_write_pubkey(&c,
213 buf,
214 is_ca ?
215 ctx->issuer_key :
216 ctx->subject_key));
217
218
219 #if defined(MBEDTLS_USE_PSA_CRYPTO)
220 status = psa_hash_compute(PSA_ALG_SHA_1,
221 buf + sizeof(buf) - len,
222 len,
223 buf + sizeof(buf) - 20,
224 20,
225 &hash_length);
226 if (status != PSA_SUCCESS) {
227 return MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED;
228 }
229 #else
230 ret = mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA1),
231 buf + sizeof(buf) - len, len,
232 buf + sizeof(buf) - 20);
233 if (ret != 0) {
234 return ret;
235 }
236 #endif /* MBEDTLS_USE_PSA_CRYPTO */
237
238 c = buf + sizeof(buf) - 20;
239 len = 20;
240
241 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
242 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, tag));
243
244 if (is_ca) { // writes AuthorityKeyIdentifier sequence
245 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
246 MBEDTLS_ASN1_CHK_ADD(len,
247 mbedtls_asn1_write_tag(&c,
248 buf,
249 MBEDTLS_ASN1_CONSTRUCTED |
250 MBEDTLS_ASN1_SEQUENCE));
251 }
252
253 if (is_ca) {
254 return mbedtls_x509write_crt_set_extension(ctx,
255 MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER,
256 MBEDTLS_OID_SIZE(
257 MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER),
258 0, buf + sizeof(buf) - len, len);
259 } else {
260 return mbedtls_x509write_crt_set_extension(ctx,
261 MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER,
262 MBEDTLS_OID_SIZE(
263 MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER),
264 0, buf + sizeof(buf) - len, len);
265 }
266 }
267
mbedtls_x509write_crt_set_subject_key_identifier(mbedtls_x509write_cert * ctx)268 int mbedtls_x509write_crt_set_subject_key_identifier(mbedtls_x509write_cert *ctx)
269 {
270 return mbedtls_x509write_crt_set_key_identifier(ctx,
271 0,
272 MBEDTLS_ASN1_OCTET_STRING);
273 }
274
mbedtls_x509write_crt_set_authority_key_identifier(mbedtls_x509write_cert * ctx)275 int mbedtls_x509write_crt_set_authority_key_identifier(mbedtls_x509write_cert *ctx)
276 {
277 return mbedtls_x509write_crt_set_key_identifier(ctx,
278 1,
279 (MBEDTLS_ASN1_CONTEXT_SPECIFIC | 0));
280 }
281 #endif /* MBEDTLS_MD_CAN_SHA1 */
282
mbedtls_x509write_crt_set_key_usage(mbedtls_x509write_cert * ctx,unsigned int key_usage)283 int mbedtls_x509write_crt_set_key_usage(mbedtls_x509write_cert *ctx,
284 unsigned int key_usage)
285 {
286 unsigned char buf[5] = { 0 }, ku[2] = { 0 };
287 unsigned char *c;
288 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
289 const unsigned int allowed_bits = MBEDTLS_X509_KU_DIGITAL_SIGNATURE |
290 MBEDTLS_X509_KU_NON_REPUDIATION |
291 MBEDTLS_X509_KU_KEY_ENCIPHERMENT |
292 MBEDTLS_X509_KU_DATA_ENCIPHERMENT |
293 MBEDTLS_X509_KU_KEY_AGREEMENT |
294 MBEDTLS_X509_KU_KEY_CERT_SIGN |
295 MBEDTLS_X509_KU_CRL_SIGN |
296 MBEDTLS_X509_KU_ENCIPHER_ONLY |
297 MBEDTLS_X509_KU_DECIPHER_ONLY;
298
299 /* Check that nothing other than the allowed flags is set */
300 if ((key_usage & ~allowed_bits) != 0) {
301 return MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE;
302 }
303
304 c = buf + 5;
305 MBEDTLS_PUT_UINT16_LE(key_usage, ku, 0);
306 ret = mbedtls_asn1_write_named_bitstring(&c, buf, ku, 9);
307
308 if (ret < 0) {
309 return ret;
310 } else if (ret < 3 || ret > 5) {
311 return MBEDTLS_ERR_X509_INVALID_FORMAT;
312 }
313
314 ret = mbedtls_x509write_crt_set_extension(ctx, MBEDTLS_OID_KEY_USAGE,
315 MBEDTLS_OID_SIZE(MBEDTLS_OID_KEY_USAGE),
316 1, c, (size_t) ret);
317 if (ret != 0) {
318 return ret;
319 }
320
321 return 0;
322 }
323
mbedtls_x509write_crt_set_ext_key_usage(mbedtls_x509write_cert * ctx,const mbedtls_asn1_sequence * exts)324 int mbedtls_x509write_crt_set_ext_key_usage(mbedtls_x509write_cert *ctx,
325 const mbedtls_asn1_sequence *exts)
326 {
327 unsigned char buf[256];
328 unsigned char *c = buf + sizeof(buf);
329 int ret;
330 size_t len = 0;
331 const mbedtls_asn1_sequence *last_ext = NULL;
332 const mbedtls_asn1_sequence *ext;
333
334 memset(buf, 0, sizeof(buf));
335
336 /* We need at least one extension: SEQUENCE SIZE (1..MAX) OF KeyPurposeId */
337 if (exts == NULL) {
338 return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
339 }
340
341 /* Iterate over exts backwards, so we write them out in the requested order */
342 while (last_ext != exts) {
343 for (ext = exts; ext->next != last_ext; ext = ext->next) {
344 }
345 if (ext->buf.tag != MBEDTLS_ASN1_OID) {
346 return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
347 }
348 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(&c, buf, ext->buf.p, ext->buf.len));
349 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, ext->buf.len));
350 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_OID));
351 last_ext = ext;
352 }
353
354 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
355 MBEDTLS_ASN1_CHK_ADD(len,
356 mbedtls_asn1_write_tag(&c, buf,
357 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));
358
359 return mbedtls_x509write_crt_set_extension(ctx,
360 MBEDTLS_OID_EXTENDED_KEY_USAGE,
361 MBEDTLS_OID_SIZE(MBEDTLS_OID_EXTENDED_KEY_USAGE),
362 1, c, len);
363 }
364
mbedtls_x509write_crt_set_ns_cert_type(mbedtls_x509write_cert * ctx,unsigned char ns_cert_type)365 int mbedtls_x509write_crt_set_ns_cert_type(mbedtls_x509write_cert *ctx,
366 unsigned char ns_cert_type)
367 {
368 unsigned char buf[4] = { 0 };
369 unsigned char *c;
370 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
371
372 c = buf + 4;
373
374 ret = mbedtls_asn1_write_named_bitstring(&c, buf, &ns_cert_type, 8);
375 if (ret < 3 || ret > 4) {
376 return ret;
377 }
378
379 ret = mbedtls_x509write_crt_set_extension(ctx, MBEDTLS_OID_NS_CERT_TYPE,
380 MBEDTLS_OID_SIZE(MBEDTLS_OID_NS_CERT_TYPE),
381 0, c, (size_t) ret);
382 if (ret != 0) {
383 return ret;
384 }
385
386 return 0;
387 }
388
x509_write_time(unsigned char ** p,unsigned char * start,const char * t,size_t size)389 static int x509_write_time(unsigned char **p, unsigned char *start,
390 const char *t, size_t size)
391 {
392 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
393 size_t len = 0;
394
395 /*
396 * write MBEDTLS_ASN1_UTC_TIME if year < 2050 (2 bytes shorter)
397 */
398 if (t[0] < '2' || (t[0] == '2' && t[1] == '0' && t[2] < '5')) {
399 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start,
400 (const unsigned char *) t + 2,
401 size - 2));
402 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
403 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
404 MBEDTLS_ASN1_UTC_TIME));
405 } else {
406 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start,
407 (const unsigned char *) t,
408 size));
409 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
410 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
411 MBEDTLS_ASN1_GENERALIZED_TIME));
412 }
413
414 return (int) len;
415 }
416
mbedtls_x509write_crt_der(mbedtls_x509write_cert * ctx,unsigned char * buf,size_t size,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)417 int mbedtls_x509write_crt_der(mbedtls_x509write_cert *ctx,
418 unsigned char *buf, size_t size,
419 int (*f_rng)(void *, unsigned char *, size_t),
420 void *p_rng)
421 {
422 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
423 const char *sig_oid;
424 size_t sig_oid_len = 0;
425 unsigned char *c, *c2;
426 unsigned char sig[MBEDTLS_PK_SIGNATURE_MAX_SIZE];
427 size_t hash_length = 0;
428 unsigned char hash[MBEDTLS_MD_MAX_SIZE];
429 #if defined(MBEDTLS_USE_PSA_CRYPTO)
430 psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
431 psa_algorithm_t psa_algorithm;
432 #endif /* MBEDTLS_USE_PSA_CRYPTO */
433
434 size_t sub_len = 0, pub_len = 0, sig_and_oid_len = 0, sig_len;
435 size_t len = 0;
436 mbedtls_pk_type_t pk_alg;
437 int write_sig_null_par;
438
439 /*
440 * Prepare data to be signed at the end of the target buffer
441 */
442 c = buf + size;
443
444 /* Signature algorithm needed in TBS, and later for actual signature */
445
446 /* There's no direct way of extracting a signature algorithm
447 * (represented as an element of mbedtls_pk_type_t) from a PK instance. */
448 if (mbedtls_pk_can_do(ctx->issuer_key, MBEDTLS_PK_RSA)) {
449 pk_alg = MBEDTLS_PK_RSA;
450 } else if (mbedtls_pk_can_do(ctx->issuer_key, MBEDTLS_PK_ECDSA)) {
451 pk_alg = MBEDTLS_PK_ECDSA;
452 } else {
453 return MBEDTLS_ERR_X509_INVALID_ALG;
454 }
455
456 if ((ret = mbedtls_oid_get_oid_by_sig_alg(pk_alg, ctx->md_alg,
457 &sig_oid, &sig_oid_len)) != 0) {
458 return ret;
459 }
460
461 /*
462 * Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension
463 */
464
465 /* Only for v3 */
466 if (ctx->version == MBEDTLS_X509_CRT_VERSION_3) {
467 MBEDTLS_ASN1_CHK_ADD(len,
468 mbedtls_x509_write_extensions(&c,
469 buf, ctx->extensions));
470 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
471 MBEDTLS_ASN1_CHK_ADD(len,
472 mbedtls_asn1_write_tag(&c, buf,
473 MBEDTLS_ASN1_CONSTRUCTED |
474 MBEDTLS_ASN1_SEQUENCE));
475 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
476 MBEDTLS_ASN1_CHK_ADD(len,
477 mbedtls_asn1_write_tag(&c, buf,
478 MBEDTLS_ASN1_CONTEXT_SPECIFIC |
479 MBEDTLS_ASN1_CONSTRUCTED | 3));
480 }
481
482 /*
483 * SubjectPublicKeyInfo
484 */
485 MBEDTLS_ASN1_CHK_ADD(pub_len,
486 mbedtls_pk_write_pubkey_der(ctx->subject_key,
487 buf, (size_t) (c - buf)));
488 c -= pub_len;
489 len += pub_len;
490
491 /*
492 * Subject ::= Name
493 */
494 MBEDTLS_ASN1_CHK_ADD(len,
495 mbedtls_x509_write_names(&c, buf,
496 ctx->subject));
497
498 /*
499 * Validity ::= SEQUENCE {
500 * notBefore Time,
501 * notAfter Time }
502 */
503 sub_len = 0;
504
505 MBEDTLS_ASN1_CHK_ADD(sub_len,
506 x509_write_time(&c, buf, ctx->not_after,
507 MBEDTLS_X509_RFC5280_UTC_TIME_LEN));
508
509 MBEDTLS_ASN1_CHK_ADD(sub_len,
510 x509_write_time(&c, buf, ctx->not_before,
511 MBEDTLS_X509_RFC5280_UTC_TIME_LEN));
512
513 len += sub_len;
514 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, sub_len));
515 MBEDTLS_ASN1_CHK_ADD(len,
516 mbedtls_asn1_write_tag(&c, buf,
517 MBEDTLS_ASN1_CONSTRUCTED |
518 MBEDTLS_ASN1_SEQUENCE));
519
520 /*
521 * Issuer ::= Name
522 */
523 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_x509_write_names(&c, buf,
524 ctx->issuer));
525
526 /*
527 * Signature ::= AlgorithmIdentifier
528 */
529 if (pk_alg == MBEDTLS_PK_ECDSA) {
530 /*
531 * The AlgorithmIdentifier's parameters field must be absent for DSA/ECDSA signature
532 * algorithms, see https://www.rfc-editor.org/rfc/rfc5480#page-17 and
533 * https://www.rfc-editor.org/rfc/rfc5758#section-3.
534 */
535 write_sig_null_par = 0;
536 } else {
537 write_sig_null_par = 1;
538 }
539 MBEDTLS_ASN1_CHK_ADD(len,
540 mbedtls_asn1_write_algorithm_identifier_ext(&c, buf,
541 sig_oid, strlen(sig_oid),
542 0, write_sig_null_par));
543
544 /*
545 * Serial ::= INTEGER
546 *
547 * Written data is:
548 * - "ctx->serial_len" bytes for the raw serial buffer
549 * - if MSb of "serial" is 1, then prepend an extra 0x00 byte
550 * - 1 byte for the length
551 * - 1 byte for the TAG
552 */
553 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(&c, buf,
554 ctx->serial, ctx->serial_len));
555 if (*c & 0x80) {
556 if (c - buf < 1) {
557 return MBEDTLS_ERR_X509_BUFFER_TOO_SMALL;
558 }
559 *(--c) = 0x0;
560 len++;
561 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf,
562 ctx->serial_len + 1));
563 } else {
564 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf,
565 ctx->serial_len));
566 }
567 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf,
568 MBEDTLS_ASN1_INTEGER));
569
570 /*
571 * Version ::= INTEGER { v1(0), v2(1), v3(2) }
572 */
573
574 /* Can be omitted for v1 */
575 if (ctx->version != MBEDTLS_X509_CRT_VERSION_1) {
576 sub_len = 0;
577 MBEDTLS_ASN1_CHK_ADD(sub_len,
578 mbedtls_asn1_write_int(&c, buf, ctx->version));
579 len += sub_len;
580 MBEDTLS_ASN1_CHK_ADD(len,
581 mbedtls_asn1_write_len(&c, buf, sub_len));
582 MBEDTLS_ASN1_CHK_ADD(len,
583 mbedtls_asn1_write_tag(&c, buf,
584 MBEDTLS_ASN1_CONTEXT_SPECIFIC |
585 MBEDTLS_ASN1_CONSTRUCTED | 0));
586 }
587
588 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
589 MBEDTLS_ASN1_CHK_ADD(len,
590 mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_CONSTRUCTED |
591 MBEDTLS_ASN1_SEQUENCE));
592
593 /*
594 * Make signature
595 */
596
597 /* Compute hash of CRT. */
598 #if defined(MBEDTLS_USE_PSA_CRYPTO)
599 psa_algorithm = mbedtls_md_psa_alg_from_type(ctx->md_alg);
600
601 status = psa_hash_compute(psa_algorithm,
602 c,
603 len,
604 hash,
605 sizeof(hash),
606 &hash_length);
607 if (status != PSA_SUCCESS) {
608 return MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED;
609 }
610 #else
611 if ((ret = mbedtls_md(mbedtls_md_info_from_type(ctx->md_alg), c,
612 len, hash)) != 0) {
613 return ret;
614 }
615 #endif /* MBEDTLS_USE_PSA_CRYPTO */
616
617
618 if ((ret = mbedtls_pk_sign(ctx->issuer_key, ctx->md_alg,
619 hash, hash_length, sig, sizeof(sig), &sig_len,
620 f_rng, p_rng)) != 0) {
621 return ret;
622 }
623
624 /* Move CRT to the front of the buffer to have space
625 * for the signature. */
626 memmove(buf, c, len);
627 c = buf + len;
628
629 /* Add signature at the end of the buffer,
630 * making sure that it doesn't underflow
631 * into the CRT buffer. */
632 c2 = buf + size;
633 MBEDTLS_ASN1_CHK_ADD(sig_and_oid_len, mbedtls_x509_write_sig(&c2, c,
634 sig_oid, sig_oid_len,
635 sig, sig_len, pk_alg));
636
637 /*
638 * Memory layout after this step:
639 *
640 * buf c=buf+len c2 buf+size
641 * [CRT0,...,CRTn, UNUSED, ..., UNUSED, SIG0, ..., SIGm]
642 */
643
644 /* Move raw CRT to just before the signature. */
645 c = c2 - len;
646 memmove(c, buf, len);
647
648 len += sig_and_oid_len;
649 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
650 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf,
651 MBEDTLS_ASN1_CONSTRUCTED |
652 MBEDTLS_ASN1_SEQUENCE));
653
654 return (int) len;
655 }
656
657 #define PEM_BEGIN_CRT "-----BEGIN CERTIFICATE-----\n"
658 #define PEM_END_CRT "-----END CERTIFICATE-----\n"
659
660 #if defined(MBEDTLS_PEM_WRITE_C)
mbedtls_x509write_crt_pem(mbedtls_x509write_cert * crt,unsigned char * buf,size_t size,int (* f_rng)(void *,unsigned char *,size_t),void * p_rng)661 int mbedtls_x509write_crt_pem(mbedtls_x509write_cert *crt,
662 unsigned char *buf, size_t size,
663 int (*f_rng)(void *, unsigned char *, size_t),
664 void *p_rng)
665 {
666 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
667 size_t olen;
668
669 if ((ret = mbedtls_x509write_crt_der(crt, buf, size,
670 f_rng, p_rng)) < 0) {
671 return ret;
672 }
673
674 if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_CRT, PEM_END_CRT,
675 buf + size - ret, ret,
676 buf, size, &olen)) != 0) {
677 return ret;
678 }
679
680 return 0;
681 }
682 #endif /* MBEDTLS_PEM_WRITE_C */
683
684 #endif /* MBEDTLS_X509_CRT_WRITE_C */
685