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;
64 struct x509_parse_context *ctx;
65 struct asymmetric_key_id *kid;
66 long ret;
67
68 ret = -ENOMEM;
69 cert = kzalloc(sizeof(struct x509_certificate), GFP_KERNEL);
70 if (!cert)
71 goto error_no_cert;
72 cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);
73 if (!cert->pub)
74 goto error_no_ctx;
75 cert->sig = kzalloc(sizeof(struct public_key_signature), GFP_KERNEL);
76 if (!cert->sig)
77 goto error_no_ctx;
78 ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL);
79 if (!ctx)
80 goto error_no_ctx;
81
82 ctx->cert = cert;
83 ctx->data = (unsigned long)data;
84
85 /* Attempt to decode the certificate */
86 ret = asn1_ber_decoder(&x509_decoder, ctx, data, datalen);
87 if (ret < 0)
88 goto error_decode;
89
90 /* Decode the AuthorityKeyIdentifier */
91 if (ctx->raw_akid) {
92 pr_devel("AKID: %u %*phN\n",
93 ctx->raw_akid_size, ctx->raw_akid_size, ctx->raw_akid);
94 ret = asn1_ber_decoder(&x509_akid_decoder, ctx,
95 ctx->raw_akid, ctx->raw_akid_size);
96 if (ret < 0) {
97 pr_warn("Couldn't decode AuthKeyIdentifier\n");
98 goto error_decode;
99 }
100 }
101
102 ret = -ENOMEM;
103 cert->pub->key = kmemdup(ctx->key, ctx->key_size, GFP_KERNEL);
104 if (!cert->pub->key)
105 goto error_decode;
106
107 cert->pub->keylen = ctx->key_size;
108
109 cert->pub->params = kmemdup(ctx->params, ctx->params_size, GFP_KERNEL);
110 if (!cert->pub->params)
111 goto error_decode;
112
113 cert->pub->paramlen = ctx->params_size;
114 cert->pub->algo = ctx->key_algo;
115
116 /* Grab the signature bits */
117 ret = x509_get_sig_params(cert);
118 if (ret < 0)
119 goto error_decode;
120
121 /* Generate cert issuer + serial number key ID */
122 kid = asymmetric_key_generate_id(cert->raw_serial,
123 cert->raw_serial_size,
124 cert->raw_issuer,
125 cert->raw_issuer_size);
126 if (IS_ERR(kid)) {
127 ret = PTR_ERR(kid);
128 goto error_decode;
129 }
130 cert->id = kid;
131
132 /* Detect self-signed certificates */
133 ret = x509_check_for_self_signed(cert);
134 if (ret < 0)
135 goto error_decode;
136
137 kfree(ctx);
138 return cert;
139
140 error_decode:
141 kfree(ctx);
142 error_no_ctx:
143 x509_free_certificate(cert);
144 error_no_cert:
145 return ERR_PTR(ret);
146 }
147 EXPORT_SYMBOL_GPL(x509_cert_parse);
148
149 /*
150 * Note an OID when we find one for later processing when we know how
151 * to interpret it.
152 */
x509_note_OID(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)153 int x509_note_OID(void *context, size_t hdrlen,
154 unsigned char tag,
155 const void *value, size_t vlen)
156 {
157 struct x509_parse_context *ctx = context;
158
159 ctx->last_oid = look_up_OID(value, vlen);
160 if (ctx->last_oid == OID__NR) {
161 char buffer[50];
162 sprint_oid(value, vlen, buffer, sizeof(buffer));
163 pr_debug("Unknown OID: [%lu] %s\n",
164 (unsigned long)value - ctx->data, buffer);
165 }
166 return 0;
167 }
168
169 /*
170 * Save the position of the TBS data so that we can check the signature over it
171 * later.
172 */
x509_note_tbs_certificate(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)173 int x509_note_tbs_certificate(void *context, size_t hdrlen,
174 unsigned char tag,
175 const void *value, size_t vlen)
176 {
177 struct x509_parse_context *ctx = context;
178
179 pr_debug("x509_note_tbs_certificate(,%zu,%02x,%ld,%zu)!\n",
180 hdrlen, tag, (unsigned long)value - ctx->data, vlen);
181
182 ctx->cert->tbs = value - hdrlen;
183 ctx->cert->tbs_size = vlen + hdrlen;
184 return 0;
185 }
186
187 /*
188 * Record the algorithm that was used to sign this certificate.
189 */
x509_note_sig_algo(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)190 int x509_note_sig_algo(void *context, size_t hdrlen, unsigned char tag,
191 const void *value, size_t vlen)
192 {
193 struct x509_parse_context *ctx = context;
194
195 pr_debug("PubKey Algo: %u\n", ctx->last_oid);
196
197 switch (ctx->last_oid) {
198 case OID_md2WithRSAEncryption:
199 case OID_md3WithRSAEncryption:
200 default:
201 return -ENOPKG; /* Unsupported combination */
202
203 case OID_md4WithRSAEncryption:
204 ctx->cert->sig->hash_algo = "md4";
205 goto rsa_pkcs1;
206
207 case OID_sha1WithRSAEncryption:
208 ctx->cert->sig->hash_algo = "sha1";
209 goto rsa_pkcs1;
210
211 case OID_sha256WithRSAEncryption:
212 ctx->cert->sig->hash_algo = "sha256";
213 goto rsa_pkcs1;
214
215 case OID_sha384WithRSAEncryption:
216 ctx->cert->sig->hash_algo = "sha384";
217 goto rsa_pkcs1;
218
219 case OID_sha512WithRSAEncryption:
220 ctx->cert->sig->hash_algo = "sha512";
221 goto rsa_pkcs1;
222
223 case OID_sha224WithRSAEncryption:
224 ctx->cert->sig->hash_algo = "sha224";
225 goto rsa_pkcs1;
226
227 case OID_id_ecdsa_with_sha1:
228 ctx->cert->sig->hash_algo = "sha1";
229 goto ecdsa;
230
231 case OID_id_ecdsa_with_sha224:
232 ctx->cert->sig->hash_algo = "sha224";
233 goto ecdsa;
234
235 case OID_id_ecdsa_with_sha256:
236 ctx->cert->sig->hash_algo = "sha256";
237 goto ecdsa;
238
239 case OID_id_ecdsa_with_sha384:
240 ctx->cert->sig->hash_algo = "sha384";
241 goto ecdsa;
242
243 case OID_id_ecdsa_with_sha512:
244 ctx->cert->sig->hash_algo = "sha512";
245 goto ecdsa;
246
247 case OID_gost2012Signature256:
248 ctx->cert->sig->hash_algo = "streebog256";
249 goto ecrdsa;
250
251 case OID_gost2012Signature512:
252 ctx->cert->sig->hash_algo = "streebog512";
253 goto ecrdsa;
254
255 case OID_SM2_with_SM3:
256 ctx->cert->sig->hash_algo = "sm3";
257 goto sm2;
258 }
259
260 rsa_pkcs1:
261 ctx->cert->sig->pkey_algo = "rsa";
262 ctx->cert->sig->encoding = "pkcs1";
263 ctx->sig_algo = ctx->last_oid;
264 return 0;
265 ecrdsa:
266 ctx->cert->sig->pkey_algo = "ecrdsa";
267 ctx->cert->sig->encoding = "raw";
268 ctx->sig_algo = ctx->last_oid;
269 return 0;
270 sm2:
271 ctx->cert->sig->pkey_algo = "sm2";
272 ctx->cert->sig->encoding = "raw";
273 ctx->sig_algo = ctx->last_oid;
274 return 0;
275 ecdsa:
276 ctx->cert->sig->pkey_algo = "ecdsa";
277 ctx->cert->sig->encoding = "x962";
278 ctx->sig_algo = ctx->last_oid;
279 return 0;
280 }
281
282 /*
283 * Note the whereabouts and type of the signature.
284 */
x509_note_signature(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)285 int x509_note_signature(void *context, size_t hdrlen,
286 unsigned char tag,
287 const void *value, size_t vlen)
288 {
289 struct x509_parse_context *ctx = context;
290
291 pr_debug("Signature: alg=%u, size=%zu\n", ctx->last_oid, vlen);
292
293 /*
294 * In X.509 certificates, the signature's algorithm is stored in two
295 * places: inside the TBSCertificate (the data that is signed), and
296 * alongside the signature. These *must* match.
297 */
298 if (ctx->last_oid != ctx->sig_algo) {
299 pr_warn("signatureAlgorithm (%u) differs from tbsCertificate.signature (%u)\n",
300 ctx->last_oid, ctx->sig_algo);
301 return -EINVAL;
302 }
303
304 if (strcmp(ctx->cert->sig->pkey_algo, "rsa") == 0 ||
305 strcmp(ctx->cert->sig->pkey_algo, "ecrdsa") == 0 ||
306 strcmp(ctx->cert->sig->pkey_algo, "sm2") == 0 ||
307 strcmp(ctx->cert->sig->pkey_algo, "ecdsa") == 0) {
308 /* Discard the BIT STRING metadata */
309 if (vlen < 1 || *(const u8 *)value != 0)
310 return -EBADMSG;
311
312 value++;
313 vlen--;
314 }
315
316 ctx->cert->raw_sig = value;
317 ctx->cert->raw_sig_size = vlen;
318 return 0;
319 }
320
321 /*
322 * Note the certificate serial number
323 */
x509_note_serial(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)324 int x509_note_serial(void *context, size_t hdrlen,
325 unsigned char tag,
326 const void *value, size_t vlen)
327 {
328 struct x509_parse_context *ctx = context;
329 ctx->cert->raw_serial = value;
330 ctx->cert->raw_serial_size = vlen;
331 return 0;
332 }
333
334 /*
335 * Note some of the name segments from which we'll fabricate a name.
336 */
x509_extract_name_segment(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)337 int x509_extract_name_segment(void *context, size_t hdrlen,
338 unsigned char tag,
339 const void *value, size_t vlen)
340 {
341 struct x509_parse_context *ctx = context;
342
343 switch (ctx->last_oid) {
344 case OID_commonName:
345 ctx->cn_size = vlen;
346 ctx->cn_offset = (unsigned long)value - ctx->data;
347 break;
348 case OID_organizationName:
349 ctx->o_size = vlen;
350 ctx->o_offset = (unsigned long)value - ctx->data;
351 break;
352 case OID_email_address:
353 ctx->email_size = vlen;
354 ctx->email_offset = (unsigned long)value - ctx->data;
355 break;
356 default:
357 break;
358 }
359
360 return 0;
361 }
362
363 /*
364 * Fabricate and save the issuer and subject names
365 */
x509_fabricate_name(struct x509_parse_context * ctx,size_t hdrlen,unsigned char tag,char ** _name,size_t vlen)366 static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen,
367 unsigned char tag,
368 char **_name, size_t vlen)
369 {
370 const void *name, *data = (const void *)ctx->data;
371 size_t namesize;
372 char *buffer;
373
374 if (*_name)
375 return -EINVAL;
376
377 /* Empty name string if no material */
378 if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) {
379 buffer = kmalloc(1, GFP_KERNEL);
380 if (!buffer)
381 return -ENOMEM;
382 buffer[0] = 0;
383 goto done;
384 }
385
386 if (ctx->cn_size && ctx->o_size) {
387 /* Consider combining O and CN, but use only the CN if it is
388 * prefixed by the O, or a significant portion thereof.
389 */
390 namesize = ctx->cn_size;
391 name = data + ctx->cn_offset;
392 if (ctx->cn_size >= ctx->o_size &&
393 memcmp(data + ctx->cn_offset, data + ctx->o_offset,
394 ctx->o_size) == 0)
395 goto single_component;
396 if (ctx->cn_size >= 7 &&
397 ctx->o_size >= 7 &&
398 memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0)
399 goto single_component;
400
401 buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1,
402 GFP_KERNEL);
403 if (!buffer)
404 return -ENOMEM;
405
406 memcpy(buffer,
407 data + ctx->o_offset, ctx->o_size);
408 buffer[ctx->o_size + 0] = ':';
409 buffer[ctx->o_size + 1] = ' ';
410 memcpy(buffer + ctx->o_size + 2,
411 data + ctx->cn_offset, ctx->cn_size);
412 buffer[ctx->o_size + 2 + ctx->cn_size] = 0;
413 goto done;
414
415 } else if (ctx->cn_size) {
416 namesize = ctx->cn_size;
417 name = data + ctx->cn_offset;
418 } else if (ctx->o_size) {
419 namesize = ctx->o_size;
420 name = data + ctx->o_offset;
421 } else {
422 namesize = ctx->email_size;
423 name = data + ctx->email_offset;
424 }
425
426 single_component:
427 buffer = kmalloc(namesize + 1, GFP_KERNEL);
428 if (!buffer)
429 return -ENOMEM;
430 memcpy(buffer, name, namesize);
431 buffer[namesize] = 0;
432
433 done:
434 *_name = buffer;
435 ctx->cn_size = 0;
436 ctx->o_size = 0;
437 ctx->email_size = 0;
438 return 0;
439 }
440
x509_note_issuer(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)441 int x509_note_issuer(void *context, size_t hdrlen,
442 unsigned char tag,
443 const void *value, size_t vlen)
444 {
445 struct x509_parse_context *ctx = context;
446 struct asymmetric_key_id *kid;
447
448 ctx->cert->raw_issuer = value;
449 ctx->cert->raw_issuer_size = vlen;
450
451 if (!ctx->cert->sig->auth_ids[2]) {
452 kid = asymmetric_key_generate_id(value, vlen, "", 0);
453 if (IS_ERR(kid))
454 return PTR_ERR(kid);
455 ctx->cert->sig->auth_ids[2] = kid;
456 }
457
458 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen);
459 }
460
x509_note_subject(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)461 int x509_note_subject(void *context, size_t hdrlen,
462 unsigned char tag,
463 const void *value, size_t vlen)
464 {
465 struct x509_parse_context *ctx = context;
466 ctx->cert->raw_subject = value;
467 ctx->cert->raw_subject_size = vlen;
468 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen);
469 }
470
471 /*
472 * Extract the parameters for the public key
473 */
x509_note_params(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)474 int x509_note_params(void *context, size_t hdrlen,
475 unsigned char tag,
476 const void *value, size_t vlen)
477 {
478 struct x509_parse_context *ctx = context;
479
480 /*
481 * AlgorithmIdentifier is used three times in the x509, we should skip
482 * first and ignore third, using second one which is after subject and
483 * before subjectPublicKey.
484 */
485 if (!ctx->cert->raw_subject || ctx->key)
486 return 0;
487 ctx->params = value - hdrlen;
488 ctx->params_size = vlen + hdrlen;
489 return 0;
490 }
491
492 /*
493 * Extract the data for the public key algorithm
494 */
x509_extract_key_data(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)495 int x509_extract_key_data(void *context, size_t hdrlen,
496 unsigned char tag,
497 const void *value, size_t vlen)
498 {
499 struct x509_parse_context *ctx = context;
500 enum OID oid;
501
502 ctx->key_algo = ctx->last_oid;
503 switch (ctx->last_oid) {
504 case OID_rsaEncryption:
505 ctx->cert->pub->pkey_algo = "rsa";
506 break;
507 case OID_gost2012PKey256:
508 case OID_gost2012PKey512:
509 ctx->cert->pub->pkey_algo = "ecrdsa";
510 break;
511 case OID_sm2:
512 ctx->cert->pub->pkey_algo = "sm2";
513 break;
514 case OID_id_ecPublicKey:
515 if (parse_OID(ctx->params, ctx->params_size, &oid) != 0)
516 return -EBADMSG;
517
518 switch (oid) {
519 case OID_sm2:
520 ctx->cert->pub->pkey_algo = "sm2";
521 break;
522 case OID_id_prime192v1:
523 ctx->cert->pub->pkey_algo = "ecdsa-nist-p192";
524 break;
525 case OID_id_prime256v1:
526 ctx->cert->pub->pkey_algo = "ecdsa-nist-p256";
527 break;
528 case OID_id_ansip384r1:
529 ctx->cert->pub->pkey_algo = "ecdsa-nist-p384";
530 break;
531 default:
532 return -ENOPKG;
533 }
534 break;
535 default:
536 return -ENOPKG;
537 }
538
539 /* Discard the BIT STRING metadata */
540 if (vlen < 1 || *(const u8 *)value != 0)
541 return -EBADMSG;
542 ctx->key = value + 1;
543 ctx->key_size = vlen - 1;
544 return 0;
545 }
546
547 /* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */
548 #define SEQ_TAG_KEYID (ASN1_CONT << 6)
549
550 /*
551 * Process certificate extensions that are used to qualify the certificate.
552 */
x509_process_extension(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)553 int x509_process_extension(void *context, size_t hdrlen,
554 unsigned char tag,
555 const void *value, size_t vlen)
556 {
557 struct x509_parse_context *ctx = context;
558 struct asymmetric_key_id *kid;
559 const unsigned char *v = value;
560
561 pr_debug("Extension: %u\n", ctx->last_oid);
562
563 if (ctx->last_oid == OID_subjectKeyIdentifier) {
564 /* Get hold of the key fingerprint */
565 if (ctx->cert->skid || vlen < 3)
566 return -EBADMSG;
567 if (v[0] != ASN1_OTS || v[1] != vlen - 2)
568 return -EBADMSG;
569 v += 2;
570 vlen -= 2;
571
572 ctx->cert->raw_skid_size = vlen;
573 ctx->cert->raw_skid = v;
574 kid = asymmetric_key_generate_id(v, vlen, "", 0);
575 if (IS_ERR(kid))
576 return PTR_ERR(kid);
577 ctx->cert->skid = kid;
578 pr_debug("subjkeyid %*phN\n", kid->len, kid->data);
579 return 0;
580 }
581
582 if (ctx->last_oid == OID_keyUsage) {
583 /*
584 * Get hold of the keyUsage bit string
585 * v[1] is the encoding size
586 * (Expect either 0x02 or 0x03, making it 1 or 2 bytes)
587 * v[2] is the number of unused bits in the bit string
588 * (If >= 3 keyCertSign is missing when v[1] = 0x02)
589 * v[3] and possibly v[4] contain the bit string
590 *
591 * From RFC 5280 4.2.1.3:
592 * 0x04 is where keyCertSign lands in this bit string
593 * 0x80 is where digitalSignature lands in this bit string
594 */
595 if (v[0] != ASN1_BTS)
596 return -EBADMSG;
597 if (vlen < 4)
598 return -EBADMSG;
599 if (v[2] >= 8)
600 return -EBADMSG;
601 if (v[3] & 0x80)
602 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_DIGITALSIG;
603 if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04))
604 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
605 else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04))
606 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
607 return 0;
608 }
609
610 if (ctx->last_oid == OID_authorityKeyIdentifier) {
611 /* Get hold of the CA key fingerprint */
612 ctx->raw_akid = v;
613 ctx->raw_akid_size = vlen;
614 return 0;
615 }
616
617 if (ctx->last_oid == OID_basicConstraints) {
618 /*
619 * Get hold of the basicConstraints
620 * v[1] is the encoding size
621 * (Expect 0x2 or greater, making it 1 or more bytes)
622 * v[2] is the encoding type
623 * (Expect an ASN1_BOOL for the CA)
624 * v[3] is the contents of the ASN1_BOOL
625 * (Expect 1 if the CA is TRUE)
626 * vlen should match the entire extension size
627 */
628 if (v[0] != (ASN1_CONS_BIT | ASN1_SEQ))
629 return -EBADMSG;
630 if (vlen < 2)
631 return -EBADMSG;
632 if (v[1] != vlen - 2)
633 return -EBADMSG;
634 if (vlen >= 4 && v[1] != 0 && v[2] == ASN1_BOOL && v[3] == 1)
635 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_CA;
636 return 0;
637 }
638
639 return 0;
640 }
641
642 /**
643 * x509_decode_time - Decode an X.509 time ASN.1 object
644 * @_t: The time to fill in
645 * @hdrlen: The length of the object header
646 * @tag: The object tag
647 * @value: The object value
648 * @vlen: The size of the object value
649 *
650 * Decode an ASN.1 universal time or generalised time field into a struct the
651 * kernel can handle and check it for validity. The time is decoded thus:
652 *
653 * [RFC5280 §4.1.2.5]
654 * CAs conforming to this profile MUST always encode certificate validity
655 * dates through the year 2049 as UTCTime; certificate validity dates in
656 * 2050 or later MUST be encoded as GeneralizedTime. Conforming
657 * applications MUST be able to process validity dates that are encoded in
658 * either UTCTime or GeneralizedTime.
659 */
x509_decode_time(time64_t * _t,size_t hdrlen,unsigned char tag,const unsigned char * value,size_t vlen)660 int x509_decode_time(time64_t *_t, size_t hdrlen,
661 unsigned char tag,
662 const unsigned char *value, size_t vlen)
663 {
664 static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30,
665 31, 31, 30, 31, 30, 31 };
666 const unsigned char *p = value;
667 unsigned year, mon, day, hour, min, sec, mon_len;
668
669 #define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; })
670 #define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
671
672 if (tag == ASN1_UNITIM) {
673 /* UTCTime: YYMMDDHHMMSSZ */
674 if (vlen != 13)
675 goto unsupported_time;
676 year = DD2bin(p);
677 if (year >= 50)
678 year += 1900;
679 else
680 year += 2000;
681 } else if (tag == ASN1_GENTIM) {
682 /* GenTime: YYYYMMDDHHMMSSZ */
683 if (vlen != 15)
684 goto unsupported_time;
685 year = DD2bin(p) * 100 + DD2bin(p);
686 if (year >= 1950 && year <= 2049)
687 goto invalid_time;
688 } else {
689 goto unsupported_time;
690 }
691
692 mon = DD2bin(p);
693 day = DD2bin(p);
694 hour = DD2bin(p);
695 min = DD2bin(p);
696 sec = DD2bin(p);
697
698 if (*p != 'Z')
699 goto unsupported_time;
700
701 if (year < 1970 ||
702 mon < 1 || mon > 12)
703 goto invalid_time;
704
705 mon_len = month_lengths[mon - 1];
706 if (mon == 2) {
707 if (year % 4 == 0) {
708 mon_len = 29;
709 if (year % 100 == 0) {
710 mon_len = 28;
711 if (year % 400 == 0)
712 mon_len = 29;
713 }
714 }
715 }
716
717 if (day < 1 || day > mon_len ||
718 hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
719 min > 59 ||
720 sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
721 goto invalid_time;
722
723 *_t = mktime64(year, mon, day, hour, min, sec);
724 return 0;
725
726 unsupported_time:
727 pr_debug("Got unsupported time [tag %02x]: '%*phN'\n",
728 tag, (int)vlen, value);
729 return -EBADMSG;
730 invalid_time:
731 pr_debug("Got invalid time [tag %02x]: '%*phN'\n",
732 tag, (int)vlen, value);
733 return -EBADMSG;
734 }
735 EXPORT_SYMBOL_GPL(x509_decode_time);
736
x509_note_not_before(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)737 int x509_note_not_before(void *context, size_t hdrlen,
738 unsigned char tag,
739 const void *value, size_t vlen)
740 {
741 struct x509_parse_context *ctx = context;
742 return x509_decode_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
743 }
744
x509_note_not_after(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)745 int x509_note_not_after(void *context, size_t hdrlen,
746 unsigned char tag,
747 const void *value, size_t vlen)
748 {
749 struct x509_parse_context *ctx = context;
750 return x509_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
751 }
752
753 /*
754 * Note a key identifier-based AuthorityKeyIdentifier
755 */
x509_akid_note_kid(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)756 int x509_akid_note_kid(void *context, size_t hdrlen,
757 unsigned char tag,
758 const void *value, size_t vlen)
759 {
760 struct x509_parse_context *ctx = context;
761 struct asymmetric_key_id *kid;
762
763 pr_debug("AKID: keyid: %*phN\n", (int)vlen, value);
764
765 if (ctx->cert->sig->auth_ids[1])
766 return 0;
767
768 kid = asymmetric_key_generate_id(value, vlen, "", 0);
769 if (IS_ERR(kid))
770 return PTR_ERR(kid);
771 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
772 ctx->cert->sig->auth_ids[1] = kid;
773 return 0;
774 }
775
776 /*
777 * Note a directoryName in an AuthorityKeyIdentifier
778 */
x509_akid_note_name(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)779 int x509_akid_note_name(void *context, size_t hdrlen,
780 unsigned char tag,
781 const void *value, size_t vlen)
782 {
783 struct x509_parse_context *ctx = context;
784
785 pr_debug("AKID: name: %*phN\n", (int)vlen, value);
786
787 ctx->akid_raw_issuer = value;
788 ctx->akid_raw_issuer_size = vlen;
789 return 0;
790 }
791
792 /*
793 * Note a serial number in an AuthorityKeyIdentifier
794 */
x509_akid_note_serial(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)795 int x509_akid_note_serial(void *context, size_t hdrlen,
796 unsigned char tag,
797 const void *value, size_t vlen)
798 {
799 struct x509_parse_context *ctx = context;
800 struct asymmetric_key_id *kid;
801
802 pr_debug("AKID: serial: %*phN\n", (int)vlen, value);
803
804 if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0])
805 return 0;
806
807 kid = asymmetric_key_generate_id(value,
808 vlen,
809 ctx->akid_raw_issuer,
810 ctx->akid_raw_issuer_size);
811 if (IS_ERR(kid))
812 return PTR_ERR(kid);
813
814 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
815 ctx->cert->sig->auth_ids[0] = kid;
816 return 0;
817 }
818