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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
19struct 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 */
44void 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}
56EXPORT_SYMBOL_GPL(x509_free_certificate);
57
58/*
59 * Parse an X.509 certificate
60 */
61struct 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
140error_decode:
141 kfree(ctx);
142error_no_ctx:
143 x509_free_certificate(cert);
144error_no_cert:
145 return ERR_PTR(ret);
146}
147EXPORT_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 */
153int 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 */
173int 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 */
190int 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
260rsa_pkcs1:
261 ctx->cert->sig->pkey_algo = "rsa";
262 ctx->cert->sig->encoding = "pkcs1";
263 ctx->sig_algo = ctx->last_oid;
264 return 0;
265ecrdsa:
266 ctx->cert->sig->pkey_algo = "ecrdsa";
267 ctx->cert->sig->encoding = "raw";
268 ctx->sig_algo = ctx->last_oid;
269 return 0;
270sm2:
271 ctx->cert->sig->pkey_algo = "sm2";
272 ctx->cert->sig->encoding = "raw";
273 ctx->sig_algo = ctx->last_oid;
274 return 0;
275ecdsa:
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 */
285int 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 */
324int 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 */
337int 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 */
366static 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
426single_component:
427 buffer = kmalloc(namesize + 1, GFP_KERNEL);
428 if (!buffer)
429 return -ENOMEM;
430 memcpy(buffer, name, namesize);
431 buffer[namesize] = 0;
432
433done:
434 *_name = buffer;
435 ctx->cn_size = 0;
436 ctx->o_size = 0;
437 ctx->email_size = 0;
438 return 0;
439}
440
441int 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
461int 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 */
474int 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 */
495int 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 */
553int 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_authorityKeyIdentifier) {
583 /* Get hold of the CA key fingerprint */
584 ctx->raw_akid = v;
585 ctx->raw_akid_size = vlen;
586 return 0;
587 }
588
589 return 0;
590}
591
592/**
593 * x509_decode_time - Decode an X.509 time ASN.1 object
594 * @_t: The time to fill in
595 * @hdrlen: The length of the object header
596 * @tag: The object tag
597 * @value: The object value
598 * @vlen: The size of the object value
599 *
600 * Decode an ASN.1 universal time or generalised time field into a struct the
601 * kernel can handle and check it for validity. The time is decoded thus:
602 *
603 * [RFC5280 ยง4.1.2.5]
604 * CAs conforming to this profile MUST always encode certificate validity
605 * dates through the year 2049 as UTCTime; certificate validity dates in
606 * 2050 or later MUST be encoded as GeneralizedTime. Conforming
607 * applications MUST be able to process validity dates that are encoded in
608 * either UTCTime or GeneralizedTime.
609 */
610int x509_decode_time(time64_t *_t, size_t hdrlen,
611 unsigned char tag,
612 const unsigned char *value, size_t vlen)
613{
614 static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30,
615 31, 31, 30, 31, 30, 31 };
616 const unsigned char *p = value;
617 unsigned year, mon, day, hour, min, sec, mon_len;
618
619#define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; })
620#define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
621
622 if (tag == ASN1_UNITIM) {
623 /* UTCTime: YYMMDDHHMMSSZ */
624 if (vlen != 13)
625 goto unsupported_time;
626 year = DD2bin(p);
627 if (year >= 50)
628 year += 1900;
629 else
630 year += 2000;
631 } else if (tag == ASN1_GENTIM) {
632 /* GenTime: YYYYMMDDHHMMSSZ */
633 if (vlen != 15)
634 goto unsupported_time;
635 year = DD2bin(p) * 100 + DD2bin(p);
636 if (year >= 1950 && year <= 2049)
637 goto invalid_time;
638 } else {
639 goto unsupported_time;
640 }
641
642 mon = DD2bin(p);
643 day = DD2bin(p);
644 hour = DD2bin(p);
645 min = DD2bin(p);
646 sec = DD2bin(p);
647
648 if (*p != 'Z')
649 goto unsupported_time;
650
651 if (year < 1970 ||
652 mon < 1 || mon > 12)
653 goto invalid_time;
654
655 mon_len = month_lengths[mon - 1];
656 if (mon == 2) {
657 if (year % 4 == 0) {
658 mon_len = 29;
659 if (year % 100 == 0) {
660 mon_len = 28;
661 if (year % 400 == 0)
662 mon_len = 29;
663 }
664 }
665 }
666
667 if (day < 1 || day > mon_len ||
668 hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
669 min > 59 ||
670 sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
671 goto invalid_time;
672
673 *_t = mktime64(year, mon, day, hour, min, sec);
674 return 0;
675
676unsupported_time:
677 pr_debug("Got unsupported time [tag %02x]: '%*phN'\n",
678 tag, (int)vlen, value);
679 return -EBADMSG;
680invalid_time:
681 pr_debug("Got invalid time [tag %02x]: '%*phN'\n",
682 tag, (int)vlen, value);
683 return -EBADMSG;
684}
685EXPORT_SYMBOL_GPL(x509_decode_time);
686
687int x509_note_not_before(void *context, size_t hdrlen,
688 unsigned char tag,
689 const void *value, size_t vlen)
690{
691 struct x509_parse_context *ctx = context;
692 return x509_decode_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
693}
694
695int x509_note_not_after(void *context, size_t hdrlen,
696 unsigned char tag,
697 const void *value, size_t vlen)
698{
699 struct x509_parse_context *ctx = context;
700 return x509_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
701}
702
703/*
704 * Note a key identifier-based AuthorityKeyIdentifier
705 */
706int x509_akid_note_kid(void *context, size_t hdrlen,
707 unsigned char tag,
708 const void *value, size_t vlen)
709{
710 struct x509_parse_context *ctx = context;
711 struct asymmetric_key_id *kid;
712
713 pr_debug("AKID: keyid: %*phN\n", (int)vlen, value);
714
715 if (ctx->cert->sig->auth_ids[1])
716 return 0;
717
718 kid = asymmetric_key_generate_id(value, vlen, "", 0);
719 if (IS_ERR(kid))
720 return PTR_ERR(kid);
721 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
722 ctx->cert->sig->auth_ids[1] = kid;
723 return 0;
724}
725
726/*
727 * Note a directoryName in an AuthorityKeyIdentifier
728 */
729int x509_akid_note_name(void *context, size_t hdrlen,
730 unsigned char tag,
731 const void *value, size_t vlen)
732{
733 struct x509_parse_context *ctx = context;
734
735 pr_debug("AKID: name: %*phN\n", (int)vlen, value);
736
737 ctx->akid_raw_issuer = value;
738 ctx->akid_raw_issuer_size = vlen;
739 return 0;
740}
741
742/*
743 * Note a serial number in an AuthorityKeyIdentifier
744 */
745int x509_akid_note_serial(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 struct asymmetric_key_id *kid;
751
752 pr_debug("AKID: serial: %*phN\n", (int)vlen, value);
753
754 if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0])
755 return 0;
756
757 kid = asymmetric_key_generate_id(value,
758 vlen,
759 ctx->akid_raw_issuer,
760 ctx->akid_raw_issuer_size);
761 if (IS_ERR(kid))
762 return PTR_ERR(kid);
763
764 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
765 ctx->cert->sig->auth_ids[0] = kid;
766 return 0;
767}
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
19struct 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 */
44void 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}
56EXPORT_SYMBOL_GPL(x509_free_certificate);
57
58/*
59 * Parse an X.509 certificate
60 */
61struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
62{
63 struct x509_certificate *cert __free(x509_free_certificate);
64 struct x509_parse_context *ctx __free(kfree) = NULL;
65 struct asymmetric_key_id *kid;
66 long ret;
67
68 cert = kzalloc(sizeof(struct x509_certificate), GFP_KERNEL);
69 if (!cert)
70 return ERR_PTR(-ENOMEM);
71 cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);
72 if (!cert->pub)
73 return ERR_PTR(-ENOMEM);
74 cert->sig = kzalloc(sizeof(struct public_key_signature), GFP_KERNEL);
75 if (!cert->sig)
76 return ERR_PTR(-ENOMEM);
77 ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL);
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}
135EXPORT_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 */
141int 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 */
161int 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 */
178int 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 }
261
262rsa_pkcs1:
263 ctx->cert->sig->pkey_algo = "rsa";
264 ctx->cert->sig->encoding = "pkcs1";
265 ctx->sig_algo = ctx->last_oid;
266 return 0;
267ecrdsa:
268 ctx->cert->sig->pkey_algo = "ecrdsa";
269 ctx->cert->sig->encoding = "raw";
270 ctx->sig_algo = ctx->last_oid;
271 return 0;
272ecdsa:
273 ctx->cert->sig->pkey_algo = "ecdsa";
274 ctx->cert->sig->encoding = "x962";
275 ctx->sig_algo = ctx->last_oid;
276 return 0;
277}
278
279/*
280 * Note the whereabouts and type of the signature.
281 */
282int x509_note_signature(void *context, size_t hdrlen,
283 unsigned char tag,
284 const void *value, size_t vlen)
285{
286 struct x509_parse_context *ctx = context;
287
288 pr_debug("Signature: alg=%u, size=%zu\n", ctx->last_oid, vlen);
289
290 /*
291 * In X.509 certificates, the signature's algorithm is stored in two
292 * places: inside the TBSCertificate (the data that is signed), and
293 * alongside the signature. These *must* match.
294 */
295 if (ctx->last_oid != ctx->sig_algo) {
296 pr_warn("signatureAlgorithm (%u) differs from tbsCertificate.signature (%u)\n",
297 ctx->last_oid, ctx->sig_algo);
298 return -EINVAL;
299 }
300
301 if (strcmp(ctx->cert->sig->pkey_algo, "rsa") == 0 ||
302 strcmp(ctx->cert->sig->pkey_algo, "ecrdsa") == 0 ||
303 strcmp(ctx->cert->sig->pkey_algo, "ecdsa") == 0) {
304 /* Discard the BIT STRING metadata */
305 if (vlen < 1 || *(const u8 *)value != 0)
306 return -EBADMSG;
307
308 value++;
309 vlen--;
310 }
311
312 ctx->cert->raw_sig = value;
313 ctx->cert->raw_sig_size = vlen;
314 return 0;
315}
316
317/*
318 * Note the certificate serial number
319 */
320int x509_note_serial(void *context, size_t hdrlen,
321 unsigned char tag,
322 const void *value, size_t vlen)
323{
324 struct x509_parse_context *ctx = context;
325 ctx->cert->raw_serial = value;
326 ctx->cert->raw_serial_size = vlen;
327 return 0;
328}
329
330/*
331 * Note some of the name segments from which we'll fabricate a name.
332 */
333int x509_extract_name_segment(void *context, size_t hdrlen,
334 unsigned char tag,
335 const void *value, size_t vlen)
336{
337 struct x509_parse_context *ctx = context;
338
339 switch (ctx->last_oid) {
340 case OID_commonName:
341 ctx->cn_size = vlen;
342 ctx->cn_offset = (unsigned long)value - ctx->data;
343 break;
344 case OID_organizationName:
345 ctx->o_size = vlen;
346 ctx->o_offset = (unsigned long)value - ctx->data;
347 break;
348 case OID_email_address:
349 ctx->email_size = vlen;
350 ctx->email_offset = (unsigned long)value - ctx->data;
351 break;
352 default:
353 break;
354 }
355
356 return 0;
357}
358
359/*
360 * Fabricate and save the issuer and subject names
361 */
362static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen,
363 unsigned char tag,
364 char **_name, size_t vlen)
365{
366 const void *name, *data = (const void *)ctx->data;
367 size_t namesize;
368 char *buffer;
369
370 if (*_name)
371 return -EINVAL;
372
373 /* Empty name string if no material */
374 if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) {
375 buffer = kmalloc(1, GFP_KERNEL);
376 if (!buffer)
377 return -ENOMEM;
378 buffer[0] = 0;
379 goto done;
380 }
381
382 if (ctx->cn_size && ctx->o_size) {
383 /* Consider combining O and CN, but use only the CN if it is
384 * prefixed by the O, or a significant portion thereof.
385 */
386 namesize = ctx->cn_size;
387 name = data + ctx->cn_offset;
388 if (ctx->cn_size >= ctx->o_size &&
389 memcmp(data + ctx->cn_offset, data + ctx->o_offset,
390 ctx->o_size) == 0)
391 goto single_component;
392 if (ctx->cn_size >= 7 &&
393 ctx->o_size >= 7 &&
394 memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0)
395 goto single_component;
396
397 buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1,
398 GFP_KERNEL);
399 if (!buffer)
400 return -ENOMEM;
401
402 memcpy(buffer,
403 data + ctx->o_offset, ctx->o_size);
404 buffer[ctx->o_size + 0] = ':';
405 buffer[ctx->o_size + 1] = ' ';
406 memcpy(buffer + ctx->o_size + 2,
407 data + ctx->cn_offset, ctx->cn_size);
408 buffer[ctx->o_size + 2 + ctx->cn_size] = 0;
409 goto done;
410
411 } else if (ctx->cn_size) {
412 namesize = ctx->cn_size;
413 name = data + ctx->cn_offset;
414 } else if (ctx->o_size) {
415 namesize = ctx->o_size;
416 name = data + ctx->o_offset;
417 } else {
418 namesize = ctx->email_size;
419 name = data + ctx->email_offset;
420 }
421
422single_component:
423 buffer = kmalloc(namesize + 1, GFP_KERNEL);
424 if (!buffer)
425 return -ENOMEM;
426 memcpy(buffer, name, namesize);
427 buffer[namesize] = 0;
428
429done:
430 *_name = buffer;
431 ctx->cn_size = 0;
432 ctx->o_size = 0;
433 ctx->email_size = 0;
434 return 0;
435}
436
437int x509_note_issuer(void *context, size_t hdrlen,
438 unsigned char tag,
439 const void *value, size_t vlen)
440{
441 struct x509_parse_context *ctx = context;
442 struct asymmetric_key_id *kid;
443
444 ctx->cert->raw_issuer = value;
445 ctx->cert->raw_issuer_size = vlen;
446
447 if (!ctx->cert->sig->auth_ids[2]) {
448 kid = asymmetric_key_generate_id(value, vlen, "", 0);
449 if (IS_ERR(kid))
450 return PTR_ERR(kid);
451 ctx->cert->sig->auth_ids[2] = kid;
452 }
453
454 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen);
455}
456
457int x509_note_subject(void *context, size_t hdrlen,
458 unsigned char tag,
459 const void *value, size_t vlen)
460{
461 struct x509_parse_context *ctx = context;
462 ctx->cert->raw_subject = value;
463 ctx->cert->raw_subject_size = vlen;
464 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen);
465}
466
467/*
468 * Extract the parameters for the public key
469 */
470int x509_note_params(void *context, size_t hdrlen,
471 unsigned char tag,
472 const void *value, size_t vlen)
473{
474 struct x509_parse_context *ctx = context;
475
476 /*
477 * AlgorithmIdentifier is used three times in the x509, we should skip
478 * first and ignore third, using second one which is after subject and
479 * before subjectPublicKey.
480 */
481 if (!ctx->cert->raw_subject || ctx->key)
482 return 0;
483 ctx->params = value - hdrlen;
484 ctx->params_size = vlen + hdrlen;
485 return 0;
486}
487
488/*
489 * Extract the data for the public key algorithm
490 */
491int x509_extract_key_data(void *context, size_t hdrlen,
492 unsigned char tag,
493 const void *value, size_t vlen)
494{
495 struct x509_parse_context *ctx = context;
496 enum OID oid;
497
498 ctx->key_algo = ctx->last_oid;
499 switch (ctx->last_oid) {
500 case OID_rsaEncryption:
501 ctx->cert->pub->pkey_algo = "rsa";
502 break;
503 case OID_gost2012PKey256:
504 case OID_gost2012PKey512:
505 ctx->cert->pub->pkey_algo = "ecrdsa";
506 break;
507 case OID_id_ecPublicKey:
508 if (parse_OID(ctx->params, ctx->params_size, &oid) != 0)
509 return -EBADMSG;
510
511 switch (oid) {
512 case OID_id_prime192v1:
513 ctx->cert->pub->pkey_algo = "ecdsa-nist-p192";
514 break;
515 case OID_id_prime256v1:
516 ctx->cert->pub->pkey_algo = "ecdsa-nist-p256";
517 break;
518 case OID_id_ansip384r1:
519 ctx->cert->pub->pkey_algo = "ecdsa-nist-p384";
520 break;
521 case OID_id_ansip521r1:
522 ctx->cert->pub->pkey_algo = "ecdsa-nist-p521";
523 break;
524 default:
525 return -ENOPKG;
526 }
527 break;
528 default:
529 return -ENOPKG;
530 }
531
532 /* Discard the BIT STRING metadata */
533 if (vlen < 1 || *(const u8 *)value != 0)
534 return -EBADMSG;
535 ctx->key = value + 1;
536 ctx->key_size = vlen - 1;
537 return 0;
538}
539
540/* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */
541#define SEQ_TAG_KEYID (ASN1_CONT << 6)
542
543/*
544 * Process certificate extensions that are used to qualify the certificate.
545 */
546int x509_process_extension(void *context, size_t hdrlen,
547 unsigned char tag,
548 const void *value, size_t vlen)
549{
550 struct x509_parse_context *ctx = context;
551 struct asymmetric_key_id *kid;
552 const unsigned char *v = value;
553
554 pr_debug("Extension: %u\n", ctx->last_oid);
555
556 if (ctx->last_oid == OID_subjectKeyIdentifier) {
557 /* Get hold of the key fingerprint */
558 if (ctx->cert->skid || vlen < 3)
559 return -EBADMSG;
560 if (v[0] != ASN1_OTS || v[1] != vlen - 2)
561 return -EBADMSG;
562 v += 2;
563 vlen -= 2;
564
565 ctx->cert->raw_skid_size = vlen;
566 ctx->cert->raw_skid = v;
567 kid = asymmetric_key_generate_id(v, vlen, "", 0);
568 if (IS_ERR(kid))
569 return PTR_ERR(kid);
570 ctx->cert->skid = kid;
571 pr_debug("subjkeyid %*phN\n", kid->len, kid->data);
572 return 0;
573 }
574
575 if (ctx->last_oid == OID_keyUsage) {
576 /*
577 * Get hold of the keyUsage bit string
578 * v[1] is the encoding size
579 * (Expect either 0x02 or 0x03, making it 1 or 2 bytes)
580 * v[2] is the number of unused bits in the bit string
581 * (If >= 3 keyCertSign is missing when v[1] = 0x02)
582 * v[3] and possibly v[4] contain the bit string
583 *
584 * From RFC 5280 4.2.1.3:
585 * 0x04 is where keyCertSign lands in this bit string
586 * 0x80 is where digitalSignature lands in this bit string
587 */
588 if (v[0] != ASN1_BTS)
589 return -EBADMSG;
590 if (vlen < 4)
591 return -EBADMSG;
592 if (v[2] >= 8)
593 return -EBADMSG;
594 if (v[3] & 0x80)
595 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_DIGITALSIG;
596 if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04))
597 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
598 else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04))
599 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
600 return 0;
601 }
602
603 if (ctx->last_oid == OID_authorityKeyIdentifier) {
604 /* Get hold of the CA key fingerprint */
605 ctx->raw_akid = v;
606 ctx->raw_akid_size = vlen;
607 return 0;
608 }
609
610 if (ctx->last_oid == OID_basicConstraints) {
611 /*
612 * Get hold of the basicConstraints
613 * v[1] is the encoding size
614 * (Expect 0x2 or greater, making it 1 or more bytes)
615 * v[2] is the encoding type
616 * (Expect an ASN1_BOOL for the CA)
617 * v[3] is the contents of the ASN1_BOOL
618 * (Expect 1 if the CA is TRUE)
619 * vlen should match the entire extension size
620 */
621 if (v[0] != (ASN1_CONS_BIT | ASN1_SEQ))
622 return -EBADMSG;
623 if (vlen < 2)
624 return -EBADMSG;
625 if (v[1] != vlen - 2)
626 return -EBADMSG;
627 if (vlen >= 4 && v[1] != 0 && v[2] == ASN1_BOOL && v[3] == 1)
628 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_CA;
629 return 0;
630 }
631
632 return 0;
633}
634
635/**
636 * x509_decode_time - Decode an X.509 time ASN.1 object
637 * @_t: The time to fill in
638 * @hdrlen: The length of the object header
639 * @tag: The object tag
640 * @value: The object value
641 * @vlen: The size of the object value
642 *
643 * Decode an ASN.1 universal time or generalised time field into a struct the
644 * kernel can handle and check it for validity. The time is decoded thus:
645 *
646 * [RFC5280 ยง4.1.2.5]
647 * CAs conforming to this profile MUST always encode certificate validity
648 * dates through the year 2049 as UTCTime; certificate validity dates in
649 * 2050 or later MUST be encoded as GeneralizedTime. Conforming
650 * applications MUST be able to process validity dates that are encoded in
651 * either UTCTime or GeneralizedTime.
652 */
653int x509_decode_time(time64_t *_t, size_t hdrlen,
654 unsigned char tag,
655 const unsigned char *value, size_t vlen)
656{
657 static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30,
658 31, 31, 30, 31, 30, 31 };
659 const unsigned char *p = value;
660 unsigned year, mon, day, hour, min, sec, mon_len;
661
662#define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; })
663#define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
664
665 if (tag == ASN1_UNITIM) {
666 /* UTCTime: YYMMDDHHMMSSZ */
667 if (vlen != 13)
668 goto unsupported_time;
669 year = DD2bin(p);
670 if (year >= 50)
671 year += 1900;
672 else
673 year += 2000;
674 } else if (tag == ASN1_GENTIM) {
675 /* GenTime: YYYYMMDDHHMMSSZ */
676 if (vlen != 15)
677 goto unsupported_time;
678 year = DD2bin(p) * 100 + DD2bin(p);
679 if (year >= 1950 && year <= 2049)
680 goto invalid_time;
681 } else {
682 goto unsupported_time;
683 }
684
685 mon = DD2bin(p);
686 day = DD2bin(p);
687 hour = DD2bin(p);
688 min = DD2bin(p);
689 sec = DD2bin(p);
690
691 if (*p != 'Z')
692 goto unsupported_time;
693
694 if (year < 1970 ||
695 mon < 1 || mon > 12)
696 goto invalid_time;
697
698 mon_len = month_lengths[mon - 1];
699 if (mon == 2) {
700 if (year % 4 == 0) {
701 mon_len = 29;
702 if (year % 100 == 0) {
703 mon_len = 28;
704 if (year % 400 == 0)
705 mon_len = 29;
706 }
707 }
708 }
709
710 if (day < 1 || day > mon_len ||
711 hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
712 min > 59 ||
713 sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
714 goto invalid_time;
715
716 *_t = mktime64(year, mon, day, hour, min, sec);
717 return 0;
718
719unsupported_time:
720 pr_debug("Got unsupported time [tag %02x]: '%*phN'\n",
721 tag, (int)vlen, value);
722 return -EBADMSG;
723invalid_time:
724 pr_debug("Got invalid time [tag %02x]: '%*phN'\n",
725 tag, (int)vlen, value);
726 return -EBADMSG;
727}
728EXPORT_SYMBOL_GPL(x509_decode_time);
729
730int x509_note_not_before(void *context, size_t hdrlen,
731 unsigned char tag,
732 const void *value, size_t vlen)
733{
734 struct x509_parse_context *ctx = context;
735 return x509_decode_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
736}
737
738int x509_note_not_after(void *context, size_t hdrlen,
739 unsigned char tag,
740 const void *value, size_t vlen)
741{
742 struct x509_parse_context *ctx = context;
743 return x509_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
744}
745
746/*
747 * Note a key identifier-based AuthorityKeyIdentifier
748 */
749int x509_akid_note_kid(void *context, size_t hdrlen,
750 unsigned char tag,
751 const void *value, size_t vlen)
752{
753 struct x509_parse_context *ctx = context;
754 struct asymmetric_key_id *kid;
755
756 pr_debug("AKID: keyid: %*phN\n", (int)vlen, value);
757
758 if (ctx->cert->sig->auth_ids[1])
759 return 0;
760
761 kid = asymmetric_key_generate_id(value, vlen, "", 0);
762 if (IS_ERR(kid))
763 return PTR_ERR(kid);
764 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
765 ctx->cert->sig->auth_ids[1] = kid;
766 return 0;
767}
768
769/*
770 * Note a directoryName in an AuthorityKeyIdentifier
771 */
772int x509_akid_note_name(void *context, size_t hdrlen,
773 unsigned char tag,
774 const void *value, size_t vlen)
775{
776 struct x509_parse_context *ctx = context;
777
778 pr_debug("AKID: name: %*phN\n", (int)vlen, value);
779
780 ctx->akid_raw_issuer = value;
781 ctx->akid_raw_issuer_size = vlen;
782 return 0;
783}
784
785/*
786 * Note a serial number in an AuthorityKeyIdentifier
787 */
788int x509_akid_note_serial(void *context, size_t hdrlen,
789 unsigned char tag,
790 const void *value, size_t vlen)
791{
792 struct x509_parse_context *ctx = context;
793 struct asymmetric_key_id *kid;
794
795 pr_debug("AKID: serial: %*phN\n", (int)vlen, value);
796
797 if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0])
798 return 0;
799
800 kid = asymmetric_key_generate_id(value,
801 vlen,
802 ctx->akid_raw_issuer,
803 ctx->akid_raw_issuer_size);
804 if (IS_ERR(kid))
805 return PTR_ERR(kid);
806
807 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
808 ctx->cert->sig->auth_ids[0] = kid;
809 return 0;
810}