1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* X.509 certificate parser
3 *
4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #define pr_fmt(fmt) "X.509: "fmt
9 #include <linux/kernel.h>
10 #include <linux/export.h>
11 #include <linux/slab.h>
12 #include <linux/err.h>
13 #include <linux/oid_registry.h>
14 #include <crypto/public_key.h>
15 #include "x509_parser.h"
16 #include "x509.asn1.h"
17 #include "x509_akid.asn1.h"
18
19 struct x509_parse_context {
20 struct x509_certificate *cert; /* Certificate being constructed */
21 unsigned long data; /* Start of data */
22 const void *key; /* Key data */
23 size_t key_size; /* Size of key data */
24 const void *params; /* Key parameters */
25 size_t params_size; /* Size of key parameters */
26 enum OID key_algo; /* Algorithm used by the cert's key */
27 enum OID last_oid; /* Last OID encountered */
28 enum OID sig_algo; /* Algorithm used to sign the cert */
29 u8 o_size; /* Size of organizationName (O) */
30 u8 cn_size; /* Size of commonName (CN) */
31 u8 email_size; /* Size of emailAddress */
32 u16 o_offset; /* Offset of organizationName (O) */
33 u16 cn_offset; /* Offset of commonName (CN) */
34 u16 email_offset; /* Offset of emailAddress */
35 unsigned raw_akid_size;
36 const void *raw_akid; /* Raw authorityKeyId in ASN.1 */
37 const void *akid_raw_issuer; /* Raw directoryName in authorityKeyId */
38 unsigned akid_raw_issuer_size;
39 };
40
41 /*
42 * Free an X.509 certificate
43 */
x509_free_certificate(struct x509_certificate * cert)44 void x509_free_certificate(struct x509_certificate *cert)
45 {
46 if (cert) {
47 public_key_free(cert->pub);
48 public_key_signature_free(cert->sig);
49 kfree(cert->issuer);
50 kfree(cert->subject);
51 kfree(cert->id);
52 kfree(cert->skid);
53 kfree(cert);
54 }
55 }
56 EXPORT_SYMBOL_GPL(x509_free_certificate);
57
58 /*
59 * Parse an X.509 certificate
60 */
x509_cert_parse(const void * data,size_t datalen)61 struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
62 {
63 struct x509_certificate *cert __free(x509_free_certificate) = NULL;
64 struct x509_parse_context *ctx __free(kfree) = NULL;
65 struct asymmetric_key_id *kid;
66 long ret;
67
68 cert = kzalloc_obj(struct x509_certificate);
69 if (!cert)
70 return ERR_PTR(-ENOMEM);
71 cert->pub = kzalloc_obj(struct public_key);
72 if (!cert->pub)
73 return ERR_PTR(-ENOMEM);
74 cert->sig = kzalloc_obj(struct public_key_signature);
75 if (!cert->sig)
76 return ERR_PTR(-ENOMEM);
77 ctx = kzalloc_obj(struct x509_parse_context);
78 if (!ctx)
79 return ERR_PTR(-ENOMEM);
80
81 ctx->cert = cert;
82 ctx->data = (unsigned long)data;
83
84 /* Attempt to decode the certificate */
85 ret = asn1_ber_decoder(&x509_decoder, ctx, data, datalen);
86 if (ret < 0)
87 return ERR_PTR(ret);
88
89 /* Decode the AuthorityKeyIdentifier */
90 if (ctx->raw_akid) {
91 pr_devel("AKID: %u %*phN\n",
92 ctx->raw_akid_size, ctx->raw_akid_size, ctx->raw_akid);
93 ret = asn1_ber_decoder(&x509_akid_decoder, ctx,
94 ctx->raw_akid, ctx->raw_akid_size);
95 if (ret < 0) {
96 pr_warn("Couldn't decode AuthKeyIdentifier\n");
97 return ERR_PTR(ret);
98 }
99 }
100
101 cert->pub->key = kmemdup(ctx->key, ctx->key_size, GFP_KERNEL);
102 if (!cert->pub->key)
103 return ERR_PTR(-ENOMEM);
104
105 cert->pub->keylen = ctx->key_size;
106
107 cert->pub->params = kmemdup(ctx->params, ctx->params_size, GFP_KERNEL);
108 if (!cert->pub->params)
109 return ERR_PTR(-ENOMEM);
110
111 cert->pub->paramlen = ctx->params_size;
112 cert->pub->algo = ctx->key_algo;
113
114 /* Grab the signature bits */
115 ret = x509_get_sig_params(cert);
116 if (ret < 0)
117 return ERR_PTR(ret);
118
119 /* Generate cert issuer + serial number key ID */
120 kid = asymmetric_key_generate_id(cert->raw_serial,
121 cert->raw_serial_size,
122 cert->raw_issuer,
123 cert->raw_issuer_size);
124 if (IS_ERR(kid))
125 return ERR_CAST(kid);
126 cert->id = kid;
127
128 /* Detect self-signed certificates */
129 ret = x509_check_for_self_signed(cert);
130 if (ret < 0)
131 return ERR_PTR(ret);
132
133 return_ptr(cert);
134 }
135 EXPORT_SYMBOL_GPL(x509_cert_parse);
136
137 /*
138 * Note an OID when we find one for later processing when we know how
139 * to interpret it.
140 */
x509_note_OID(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)141 int x509_note_OID(void *context, size_t hdrlen,
142 unsigned char tag,
143 const void *value, size_t vlen)
144 {
145 struct x509_parse_context *ctx = context;
146
147 ctx->last_oid = look_up_OID(value, vlen);
148 if (ctx->last_oid == OID__NR) {
149 char buffer[50];
150 sprint_oid(value, vlen, buffer, sizeof(buffer));
151 pr_debug("Unknown OID: [%lu] %s\n",
152 (unsigned long)value - ctx->data, buffer);
153 }
154 return 0;
155 }
156
157 /*
158 * Save the position of the TBS data so that we can check the signature over it
159 * later.
160 */
x509_note_tbs_certificate(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)161 int x509_note_tbs_certificate(void *context, size_t hdrlen,
162 unsigned char tag,
163 const void *value, size_t vlen)
164 {
165 struct x509_parse_context *ctx = context;
166
167 pr_debug("x509_note_tbs_certificate(,%zu,%02x,%ld,%zu)!\n",
168 hdrlen, tag, (unsigned long)value - ctx->data, vlen);
169
170 ctx->cert->tbs = value - hdrlen;
171 ctx->cert->tbs_size = vlen + hdrlen;
172 return 0;
173 }
174
175 /*
176 * Record the algorithm that was used to sign this certificate.
177 */
x509_note_sig_algo(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)178 int x509_note_sig_algo(void *context, size_t hdrlen, unsigned char tag,
179 const void *value, size_t vlen)
180 {
181 struct x509_parse_context *ctx = context;
182
183 pr_debug("PubKey Algo: %u\n", ctx->last_oid);
184
185 switch (ctx->last_oid) {
186 default:
187 return -ENOPKG; /* Unsupported combination */
188
189 case OID_sha1WithRSAEncryption:
190 ctx->cert->sig->hash_algo = "sha1";
191 goto rsa_pkcs1;
192
193 case OID_sha256WithRSAEncryption:
194 ctx->cert->sig->hash_algo = "sha256";
195 goto rsa_pkcs1;
196
197 case OID_sha384WithRSAEncryption:
198 ctx->cert->sig->hash_algo = "sha384";
199 goto rsa_pkcs1;
200
201 case OID_sha512WithRSAEncryption:
202 ctx->cert->sig->hash_algo = "sha512";
203 goto rsa_pkcs1;
204
205 case OID_sha224WithRSAEncryption:
206 ctx->cert->sig->hash_algo = "sha224";
207 goto rsa_pkcs1;
208
209 case OID_id_ecdsa_with_sha1:
210 ctx->cert->sig->hash_algo = "sha1";
211 goto ecdsa;
212
213 case OID_id_rsassa_pkcs1_v1_5_with_sha3_256:
214 ctx->cert->sig->hash_algo = "sha3-256";
215 goto rsa_pkcs1;
216
217 case OID_id_rsassa_pkcs1_v1_5_with_sha3_384:
218 ctx->cert->sig->hash_algo = "sha3-384";
219 goto rsa_pkcs1;
220
221 case OID_id_rsassa_pkcs1_v1_5_with_sha3_512:
222 ctx->cert->sig->hash_algo = "sha3-512";
223 goto rsa_pkcs1;
224
225 case OID_id_ecdsa_with_sha224:
226 ctx->cert->sig->hash_algo = "sha224";
227 goto ecdsa;
228
229 case OID_id_ecdsa_with_sha256:
230 ctx->cert->sig->hash_algo = "sha256";
231 goto ecdsa;
232
233 case OID_id_ecdsa_with_sha384:
234 ctx->cert->sig->hash_algo = "sha384";
235 goto ecdsa;
236
237 case OID_id_ecdsa_with_sha512:
238 ctx->cert->sig->hash_algo = "sha512";
239 goto ecdsa;
240
241 case OID_id_ecdsa_with_sha3_256:
242 ctx->cert->sig->hash_algo = "sha3-256";
243 goto ecdsa;
244
245 case OID_id_ecdsa_with_sha3_384:
246 ctx->cert->sig->hash_algo = "sha3-384";
247 goto ecdsa;
248
249 case OID_id_ecdsa_with_sha3_512:
250 ctx->cert->sig->hash_algo = "sha3-512";
251 goto ecdsa;
252
253 case OID_gost2012Signature256:
254 ctx->cert->sig->hash_algo = "streebog256";
255 goto ecrdsa;
256
257 case OID_gost2012Signature512:
258 ctx->cert->sig->hash_algo = "streebog512";
259 goto ecrdsa;
260 case OID_id_ml_dsa_44:
261 ctx->cert->sig->pkey_algo = "mldsa44";
262 goto ml_dsa;
263 case OID_id_ml_dsa_65:
264 ctx->cert->sig->pkey_algo = "mldsa65";
265 goto ml_dsa;
266 case OID_id_ml_dsa_87:
267 ctx->cert->sig->pkey_algo = "mldsa87";
268 goto ml_dsa;
269 }
270
271 rsa_pkcs1:
272 ctx->cert->sig->pkey_algo = "rsa";
273 ctx->cert->sig->encoding = "pkcs1";
274 ctx->sig_algo = ctx->last_oid;
275 return 0;
276 ecrdsa:
277 ctx->cert->sig->pkey_algo = "ecrdsa";
278 ctx->cert->sig->encoding = "raw";
279 ctx->sig_algo = ctx->last_oid;
280 return 0;
281 ecdsa:
282 ctx->cert->sig->pkey_algo = "ecdsa";
283 ctx->cert->sig->encoding = "x962";
284 ctx->sig_algo = ctx->last_oid;
285 return 0;
286 ml_dsa:
287 ctx->cert->sig->algo_takes_data = true;
288 ctx->cert->sig->hash_algo = "none";
289 ctx->cert->sig->encoding = "raw";
290 ctx->sig_algo = ctx->last_oid;
291 return 0;
292 }
293
294 /*
295 * Note the whereabouts and type of the signature.
296 */
x509_note_signature(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)297 int x509_note_signature(void *context, size_t hdrlen,
298 unsigned char tag,
299 const void *value, size_t vlen)
300 {
301 struct x509_parse_context *ctx = context;
302
303 pr_debug("Signature: alg=%u, size=%zu\n", ctx->last_oid, vlen);
304
305 /*
306 * In X.509 certificates, the signature's algorithm is stored in two
307 * places: inside the TBSCertificate (the data that is signed), and
308 * alongside the signature. These *must* match.
309 */
310 if (ctx->last_oid != ctx->sig_algo) {
311 pr_warn("signatureAlgorithm (%u) differs from tbsCertificate.signature (%u)\n",
312 ctx->last_oid, ctx->sig_algo);
313 return -EINVAL;
314 }
315
316 if (strcmp(ctx->cert->sig->pkey_algo, "rsa") == 0 ||
317 strcmp(ctx->cert->sig->pkey_algo, "ecrdsa") == 0 ||
318 strcmp(ctx->cert->sig->pkey_algo, "ecdsa") == 0 ||
319 strncmp(ctx->cert->sig->pkey_algo, "mldsa", 5) == 0) {
320 /* Discard the BIT STRING metadata */
321 if (vlen < 1 || *(const u8 *)value != 0)
322 return -EBADMSG;
323
324 value++;
325 vlen--;
326 }
327
328 ctx->cert->raw_sig = value;
329 ctx->cert->raw_sig_size = vlen;
330 return 0;
331 }
332
333 /*
334 * Note the certificate serial number
335 */
x509_note_serial(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)336 int x509_note_serial(void *context, size_t hdrlen,
337 unsigned char tag,
338 const void *value, size_t vlen)
339 {
340 struct x509_parse_context *ctx = context;
341 ctx->cert->raw_serial = value;
342 ctx->cert->raw_serial_size = vlen;
343 return 0;
344 }
345
346 /*
347 * Note some of the name segments from which we'll fabricate a name.
348 */
x509_extract_name_segment(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)349 int x509_extract_name_segment(void *context, size_t hdrlen,
350 unsigned char tag,
351 const void *value, size_t vlen)
352 {
353 struct x509_parse_context *ctx = context;
354
355 switch (ctx->last_oid) {
356 case OID_commonName:
357 ctx->cn_size = vlen;
358 ctx->cn_offset = (unsigned long)value - ctx->data;
359 break;
360 case OID_organizationName:
361 ctx->o_size = vlen;
362 ctx->o_offset = (unsigned long)value - ctx->data;
363 break;
364 case OID_email_address:
365 ctx->email_size = vlen;
366 ctx->email_offset = (unsigned long)value - ctx->data;
367 break;
368 default:
369 break;
370 }
371
372 return 0;
373 }
374
375 /*
376 * Fabricate and save the issuer and subject names
377 */
x509_fabricate_name(struct x509_parse_context * ctx,size_t hdrlen,unsigned char tag,char ** _name,size_t vlen)378 static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen,
379 unsigned char tag,
380 char **_name, size_t vlen)
381 {
382 const void *name, *data = (const void *)ctx->data;
383 size_t namesize;
384 char *buffer;
385
386 if (*_name)
387 return -EINVAL;
388
389 /* Empty name string if no material */
390 if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) {
391 buffer = kzalloc(1, GFP_KERNEL);
392 if (!buffer)
393 return -ENOMEM;
394 goto done;
395 }
396
397 if (ctx->cn_size && ctx->o_size) {
398 /* Consider combining O and CN, but use only the CN if it is
399 * prefixed by the O, or a significant portion thereof.
400 */
401 namesize = ctx->cn_size;
402 name = data + ctx->cn_offset;
403 if (ctx->cn_size >= ctx->o_size &&
404 memcmp(data + ctx->cn_offset, data + ctx->o_offset,
405 ctx->o_size) == 0)
406 goto single_component;
407 if (ctx->cn_size >= 7 &&
408 ctx->o_size >= 7 &&
409 memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0)
410 goto single_component;
411
412 buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1,
413 GFP_KERNEL);
414 if (!buffer)
415 return -ENOMEM;
416
417 memcpy(buffer,
418 data + ctx->o_offset, ctx->o_size);
419 buffer[ctx->o_size + 0] = ':';
420 buffer[ctx->o_size + 1] = ' ';
421 memcpy(buffer + ctx->o_size + 2,
422 data + ctx->cn_offset, ctx->cn_size);
423 buffer[ctx->o_size + 2 + ctx->cn_size] = 0;
424 goto done;
425
426 } else if (ctx->cn_size) {
427 namesize = ctx->cn_size;
428 name = data + ctx->cn_offset;
429 } else if (ctx->o_size) {
430 namesize = ctx->o_size;
431 name = data + ctx->o_offset;
432 } else {
433 namesize = ctx->email_size;
434 name = data + ctx->email_offset;
435 }
436
437 single_component:
438 buffer = kmalloc(namesize + 1, GFP_KERNEL);
439 if (!buffer)
440 return -ENOMEM;
441 memcpy(buffer, name, namesize);
442 buffer[namesize] = 0;
443
444 done:
445 *_name = buffer;
446 ctx->cn_size = 0;
447 ctx->o_size = 0;
448 ctx->email_size = 0;
449 return 0;
450 }
451
x509_note_issuer(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)452 int x509_note_issuer(void *context, size_t hdrlen,
453 unsigned char tag,
454 const void *value, size_t vlen)
455 {
456 struct x509_parse_context *ctx = context;
457 struct asymmetric_key_id *kid;
458
459 ctx->cert->raw_issuer = value;
460 ctx->cert->raw_issuer_size = vlen;
461
462 if (!ctx->cert->sig->auth_ids[2]) {
463 kid = asymmetric_key_generate_id(value, vlen, "", 0);
464 if (IS_ERR(kid))
465 return PTR_ERR(kid);
466 ctx->cert->sig->auth_ids[2] = kid;
467 }
468
469 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen);
470 }
471
x509_note_subject(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)472 int x509_note_subject(void *context, size_t hdrlen,
473 unsigned char tag,
474 const void *value, size_t vlen)
475 {
476 struct x509_parse_context *ctx = context;
477 ctx->cert->raw_subject = value;
478 ctx->cert->raw_subject_size = vlen;
479 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen);
480 }
481
482 /*
483 * Extract the parameters for the public key
484 */
x509_note_params(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)485 int x509_note_params(void *context, size_t hdrlen,
486 unsigned char tag,
487 const void *value, size_t vlen)
488 {
489 struct x509_parse_context *ctx = context;
490
491 /*
492 * AlgorithmIdentifier is used three times in the x509, we should skip
493 * first and ignore third, using second one which is after subject and
494 * before subjectPublicKey.
495 */
496 if (!ctx->cert->raw_subject || ctx->key)
497 return 0;
498 ctx->params = value - hdrlen;
499 ctx->params_size = vlen + hdrlen;
500 return 0;
501 }
502
503 /*
504 * Extract the data for the public key algorithm
505 */
x509_extract_key_data(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)506 int x509_extract_key_data(void *context, size_t hdrlen,
507 unsigned char tag,
508 const void *value, size_t vlen)
509 {
510 struct x509_parse_context *ctx = context;
511 enum OID oid;
512
513 ctx->key_algo = ctx->last_oid;
514 switch (ctx->last_oid) {
515 case OID_rsaEncryption:
516 ctx->cert->pub->pkey_algo = "rsa";
517 break;
518 case OID_gost2012PKey256:
519 case OID_gost2012PKey512:
520 ctx->cert->pub->pkey_algo = "ecrdsa";
521 break;
522 case OID_id_ecPublicKey:
523 if (parse_OID(ctx->params, ctx->params_size, &oid) != 0)
524 return -EBADMSG;
525
526 switch (oid) {
527 case OID_id_prime192v1:
528 ctx->cert->pub->pkey_algo = "ecdsa-nist-p192";
529 break;
530 case OID_id_prime256v1:
531 ctx->cert->pub->pkey_algo = "ecdsa-nist-p256";
532 break;
533 case OID_id_ansip384r1:
534 ctx->cert->pub->pkey_algo = "ecdsa-nist-p384";
535 break;
536 case OID_id_ansip521r1:
537 ctx->cert->pub->pkey_algo = "ecdsa-nist-p521";
538 break;
539 default:
540 return -ENOPKG;
541 }
542 break;
543 case OID_id_ml_dsa_44:
544 ctx->cert->pub->pkey_algo = "mldsa44";
545 break;
546 case OID_id_ml_dsa_65:
547 ctx->cert->pub->pkey_algo = "mldsa65";
548 break;
549 case OID_id_ml_dsa_87:
550 ctx->cert->pub->pkey_algo = "mldsa87";
551 break;
552 default:
553 return -ENOPKG;
554 }
555
556 /* Discard the BIT STRING metadata */
557 if (vlen < 1 || *(const u8 *)value != 0)
558 return -EBADMSG;
559 ctx->key = value + 1;
560 ctx->key_size = vlen - 1;
561 return 0;
562 }
563
564 /* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */
565 #define SEQ_TAG_KEYID (ASN1_CONT << 6)
566
567 /*
568 * Process certificate extensions that are used to qualify the certificate.
569 */
x509_process_extension(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)570 int x509_process_extension(void *context, size_t hdrlen,
571 unsigned char tag,
572 const void *value, size_t vlen)
573 {
574 struct x509_parse_context *ctx = context;
575 struct asymmetric_key_id *kid;
576 const unsigned char *v = value;
577
578 pr_debug("Extension: %u\n", ctx->last_oid);
579
580 if (ctx->last_oid == OID_subjectKeyIdentifier) {
581 /* Get hold of the key fingerprint */
582 if (ctx->cert->skid || vlen < 3)
583 return -EBADMSG;
584 if (v[0] != ASN1_OTS || v[1] != vlen - 2)
585 return -EBADMSG;
586 v += 2;
587 vlen -= 2;
588
589 ctx->cert->raw_skid_size = vlen;
590 ctx->cert->raw_skid = v;
591 kid = asymmetric_key_generate_id(v, vlen, "", 0);
592 if (IS_ERR(kid))
593 return PTR_ERR(kid);
594 ctx->cert->skid = kid;
595 pr_debug("subjkeyid %*phN\n", kid->len, kid->data);
596 return 0;
597 }
598
599 if (ctx->last_oid == OID_keyUsage) {
600 /*
601 * Get hold of the keyUsage bit string
602 * v[1] is the encoding size
603 * (Expect either 0x02 or 0x03, making it 1 or 2 bytes)
604 * v[2] is the number of unused bits in the bit string
605 * (If >= 3 keyCertSign is missing when v[1] = 0x02)
606 * v[3] and possibly v[4] contain the bit string
607 *
608 * From RFC 5280 4.2.1.3:
609 * 0x04 is where keyCertSign lands in this bit string
610 * 0x80 is where digitalSignature lands in this bit string
611 */
612 if (v[0] != ASN1_BTS)
613 return -EBADMSG;
614 if (vlen < 4)
615 return -EBADMSG;
616 if (v[2] >= 8)
617 return -EBADMSG;
618 if (v[3] & 0x80)
619 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_DIGITALSIG;
620 if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04))
621 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
622 else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04))
623 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
624 return 0;
625 }
626
627 if (ctx->last_oid == OID_authorityKeyIdentifier) {
628 /* Get hold of the CA key fingerprint */
629 ctx->raw_akid = v;
630 ctx->raw_akid_size = vlen;
631 return 0;
632 }
633
634 if (ctx->last_oid == OID_basicConstraints) {
635 /*
636 * Get hold of the basicConstraints
637 * v[1] is the encoding size
638 * (Expect 0x00 for empty SEQUENCE with CA:FALSE, or
639 * 0x03 or greater for non-empty SEQUENCE)
640 * v[2] is the encoding type
641 * (Expect an ASN1_BOOL for the CA)
642 * v[3] is the length of the ASN1_BOOL
643 * (Expect 1 for a single byte boolean)
644 * v[4] is the contents of the ASN1_BOOL
645 * (Expect 0xFF if the CA is TRUE)
646 * vlen should match the entire extension size
647 */
648 if (v[0] != (ASN1_CONS_BIT | ASN1_SEQ))
649 return -EBADMSG;
650 if (vlen < 2)
651 return -EBADMSG;
652 if (v[1] != vlen - 2)
653 return -EBADMSG;
654 /* Empty SEQUENCE means CA:FALSE (default value omitted per DER) */
655 if (v[1] == 0)
656 return 0;
657 if (vlen >= 5 && v[2] == ASN1_BOOL && v[3] == 1 && v[4] == 0xFF)
658 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_CA;
659 else
660 return -EBADMSG;
661 return 0;
662 }
663
664 return 0;
665 }
666
667 /**
668 * x509_decode_time - Decode an X.509 time ASN.1 object
669 * @_t: The time to fill in
670 * @hdrlen: The length of the object header
671 * @tag: The object tag
672 * @value: The object value
673 * @vlen: The size of the object value
674 *
675 * Decode an ASN.1 universal time or generalised time field into a struct the
676 * kernel can handle and check it for validity. The time is decoded thus:
677 *
678 * [RFC5280 §4.1.2.5]
679 * CAs conforming to this profile MUST always encode certificate validity
680 * dates through the year 2049 as UTCTime; certificate validity dates in
681 * 2050 or later MUST be encoded as GeneralizedTime. Conforming
682 * applications MUST be able to process validity dates that are encoded in
683 * either UTCTime or GeneralizedTime.
684 */
x509_decode_time(time64_t * _t,size_t hdrlen,unsigned char tag,const unsigned char * value,size_t vlen)685 int x509_decode_time(time64_t *_t, size_t hdrlen,
686 unsigned char tag,
687 const unsigned char *value, size_t vlen)
688 {
689 static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30,
690 31, 31, 30, 31, 30, 31 };
691 const unsigned char *p = value;
692 unsigned year, mon, day, hour, min, sec, mon_len;
693
694 #define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; })
695 #define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
696
697 if (tag == ASN1_UNITIM) {
698 /* UTCTime: YYMMDDHHMMSSZ */
699 if (vlen != 13)
700 goto unsupported_time;
701 year = DD2bin(p);
702 if (year >= 50)
703 year += 1900;
704 else
705 year += 2000;
706 } else if (tag == ASN1_GENTIM) {
707 /* GenTime: YYYYMMDDHHMMSSZ */
708 if (vlen != 15)
709 goto unsupported_time;
710 year = DD2bin(p) * 100 + DD2bin(p);
711 if (year >= 1950 && year <= 2049)
712 goto invalid_time;
713 } else {
714 goto unsupported_time;
715 }
716
717 mon = DD2bin(p);
718 day = DD2bin(p);
719 hour = DD2bin(p);
720 min = DD2bin(p);
721 sec = DD2bin(p);
722
723 if (*p != 'Z')
724 goto unsupported_time;
725
726 if (year < 1970 ||
727 mon < 1 || mon > 12)
728 goto invalid_time;
729
730 mon_len = month_lengths[mon - 1];
731 if (mon == 2) {
732 if (year % 4 == 0) {
733 mon_len = 29;
734 if (year % 100 == 0) {
735 mon_len = 28;
736 if (year % 400 == 0)
737 mon_len = 29;
738 }
739 }
740 }
741
742 if (day < 1 || day > mon_len ||
743 hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
744 min > 59 ||
745 sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
746 goto invalid_time;
747
748 *_t = mktime64(year, mon, day, hour, min, sec);
749 return 0;
750
751 unsupported_time:
752 pr_debug("Got unsupported time [tag %02x]: '%*phN'\n",
753 tag, (int)vlen, value);
754 return -EBADMSG;
755 invalid_time:
756 pr_debug("Got invalid time [tag %02x]: '%*phN'\n",
757 tag, (int)vlen, value);
758 return -EBADMSG;
759 }
760 EXPORT_SYMBOL_GPL(x509_decode_time);
761
x509_note_not_before(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)762 int x509_note_not_before(void *context, size_t hdrlen,
763 unsigned char tag,
764 const void *value, size_t vlen)
765 {
766 struct x509_parse_context *ctx = context;
767 return x509_decode_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
768 }
769
x509_note_not_after(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)770 int x509_note_not_after(void *context, size_t hdrlen,
771 unsigned char tag,
772 const void *value, size_t vlen)
773 {
774 struct x509_parse_context *ctx = context;
775 return x509_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
776 }
777
778 /*
779 * Note a key identifier-based AuthorityKeyIdentifier
780 */
x509_akid_note_kid(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)781 int x509_akid_note_kid(void *context, size_t hdrlen,
782 unsigned char tag,
783 const void *value, size_t vlen)
784 {
785 struct x509_parse_context *ctx = context;
786 struct asymmetric_key_id *kid;
787
788 pr_debug("AKID: keyid: %*phN\n", (int)vlen, value);
789
790 if (ctx->cert->sig->auth_ids[1])
791 return 0;
792
793 kid = asymmetric_key_generate_id(value, vlen, "", 0);
794 if (IS_ERR(kid))
795 return PTR_ERR(kid);
796 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
797 ctx->cert->sig->auth_ids[1] = kid;
798 return 0;
799 }
800
801 /*
802 * Note a directoryName in an AuthorityKeyIdentifier
803 */
x509_akid_note_name(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)804 int x509_akid_note_name(void *context, size_t hdrlen,
805 unsigned char tag,
806 const void *value, size_t vlen)
807 {
808 struct x509_parse_context *ctx = context;
809
810 pr_debug("AKID: name: %*phN\n", (int)vlen, value);
811
812 ctx->akid_raw_issuer = value;
813 ctx->akid_raw_issuer_size = vlen;
814 return 0;
815 }
816
817 /*
818 * Note a serial number in an AuthorityKeyIdentifier
819 */
x509_akid_note_serial(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)820 int x509_akid_note_serial(void *context, size_t hdrlen,
821 unsigned char tag,
822 const void *value, size_t vlen)
823 {
824 struct x509_parse_context *ctx = context;
825 struct asymmetric_key_id *kid;
826
827 pr_debug("AKID: serial: %*phN\n", (int)vlen, value);
828
829 if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0])
830 return 0;
831
832 kid = asymmetric_key_generate_id(value,
833 vlen,
834 ctx->akid_raw_issuer,
835 ctx->akid_raw_issuer_size);
836 if (IS_ERR(kid))
837 return PTR_ERR(kid);
838
839 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
840 ctx->cert->sig->auth_ids[0] = kid;
841 return 0;
842 }
843