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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;
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 default:
199 return -ENOPKG; /* Unsupported combination */
200
201 case OID_sha256WithRSAEncryption:
202 ctx->cert->sig->hash_algo = "sha256";
203 goto rsa_pkcs1;
204
205 case OID_sha384WithRSAEncryption:
206 ctx->cert->sig->hash_algo = "sha384";
207 goto rsa_pkcs1;
208
209 case OID_sha512WithRSAEncryption:
210 ctx->cert->sig->hash_algo = "sha512";
211 goto rsa_pkcs1;
212
213 case OID_sha224WithRSAEncryption:
214 ctx->cert->sig->hash_algo = "sha224";
215 goto rsa_pkcs1;
216
217 case OID_id_rsassa_pkcs1_v1_5_with_sha3_256:
218 ctx->cert->sig->hash_algo = "sha3-256";
219 goto rsa_pkcs1;
220
221 case OID_id_rsassa_pkcs1_v1_5_with_sha3_384:
222 ctx->cert->sig->hash_algo = "sha3-384";
223 goto rsa_pkcs1;
224
225 case OID_id_rsassa_pkcs1_v1_5_with_sha3_512:
226 ctx->cert->sig->hash_algo = "sha3-512";
227 goto rsa_pkcs1;
228
229 case OID_id_ecdsa_with_sha224:
230 ctx->cert->sig->hash_algo = "sha224";
231 goto ecdsa;
232
233 case OID_id_ecdsa_with_sha256:
234 ctx->cert->sig->hash_algo = "sha256";
235 goto ecdsa;
236
237 case OID_id_ecdsa_with_sha384:
238 ctx->cert->sig->hash_algo = "sha384";
239 goto ecdsa;
240
241 case OID_id_ecdsa_with_sha512:
242 ctx->cert->sig->hash_algo = "sha512";
243 goto ecdsa;
244
245 case OID_id_ecdsa_with_sha3_256:
246 ctx->cert->sig->hash_algo = "sha3-256";
247 goto ecdsa;
248
249 case OID_id_ecdsa_with_sha3_384:
250 ctx->cert->sig->hash_algo = "sha3-384";
251 goto ecdsa;
252
253 case OID_id_ecdsa_with_sha3_512:
254 ctx->cert->sig->hash_algo = "sha3-512";
255 goto ecdsa;
256
257 case OID_gost2012Signature256:
258 ctx->cert->sig->hash_algo = "streebog256";
259 goto ecrdsa;
260
261 case OID_gost2012Signature512:
262 ctx->cert->sig->hash_algo = "streebog512";
263 goto ecrdsa;
264
265 case OID_SM2_with_SM3:
266 ctx->cert->sig->hash_algo = "sm3";
267 goto sm2;
268 }
269
270rsa_pkcs1:
271 ctx->cert->sig->pkey_algo = "rsa";
272 ctx->cert->sig->encoding = "pkcs1";
273 ctx->sig_algo = ctx->last_oid;
274 return 0;
275ecrdsa:
276 ctx->cert->sig->pkey_algo = "ecrdsa";
277 ctx->cert->sig->encoding = "raw";
278 ctx->sig_algo = ctx->last_oid;
279 return 0;
280sm2:
281 ctx->cert->sig->pkey_algo = "sm2";
282 ctx->cert->sig->encoding = "raw";
283 ctx->sig_algo = ctx->last_oid;
284 return 0;
285ecdsa:
286 ctx->cert->sig->pkey_algo = "ecdsa";
287 ctx->cert->sig->encoding = "x962";
288 ctx->sig_algo = ctx->last_oid;
289 return 0;
290}
291
292/*
293 * Note the whereabouts and type of the signature.
294 */
295int x509_note_signature(void *context, size_t hdrlen,
296 unsigned char tag,
297 const void *value, size_t vlen)
298{
299 struct x509_parse_context *ctx = context;
300
301 pr_debug("Signature: alg=%u, size=%zu\n", ctx->last_oid, vlen);
302
303 /*
304 * In X.509 certificates, the signature's algorithm is stored in two
305 * places: inside the TBSCertificate (the data that is signed), and
306 * alongside the signature. These *must* match.
307 */
308 if (ctx->last_oid != ctx->sig_algo) {
309 pr_warn("signatureAlgorithm (%u) differs from tbsCertificate.signature (%u)\n",
310 ctx->last_oid, ctx->sig_algo);
311 return -EINVAL;
312 }
313
314 if (strcmp(ctx->cert->sig->pkey_algo, "rsa") == 0 ||
315 strcmp(ctx->cert->sig->pkey_algo, "ecrdsa") == 0 ||
316 strcmp(ctx->cert->sig->pkey_algo, "sm2") == 0 ||
317 strcmp(ctx->cert->sig->pkey_algo, "ecdsa") == 0) {
318 /* Discard the BIT STRING metadata */
319 if (vlen < 1 || *(const u8 *)value != 0)
320 return -EBADMSG;
321
322 value++;
323 vlen--;
324 }
325
326 ctx->cert->raw_sig = value;
327 ctx->cert->raw_sig_size = vlen;
328 return 0;
329}
330
331/*
332 * Note the certificate serial number
333 */
334int x509_note_serial(void *context, size_t hdrlen,
335 unsigned char tag,
336 const void *value, size_t vlen)
337{
338 struct x509_parse_context *ctx = context;
339 ctx->cert->raw_serial = value;
340 ctx->cert->raw_serial_size = vlen;
341 return 0;
342}
343
344/*
345 * Note some of the name segments from which we'll fabricate a name.
346 */
347int x509_extract_name_segment(void *context, size_t hdrlen,
348 unsigned char tag,
349 const void *value, size_t vlen)
350{
351 struct x509_parse_context *ctx = context;
352
353 switch (ctx->last_oid) {
354 case OID_commonName:
355 ctx->cn_size = vlen;
356 ctx->cn_offset = (unsigned long)value - ctx->data;
357 break;
358 case OID_organizationName:
359 ctx->o_size = vlen;
360 ctx->o_offset = (unsigned long)value - ctx->data;
361 break;
362 case OID_email_address:
363 ctx->email_size = vlen;
364 ctx->email_offset = (unsigned long)value - ctx->data;
365 break;
366 default:
367 break;
368 }
369
370 return 0;
371}
372
373/*
374 * Fabricate and save the issuer and subject names
375 */
376static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen,
377 unsigned char tag,
378 char **_name, size_t vlen)
379{
380 const void *name, *data = (const void *)ctx->data;
381 size_t namesize;
382 char *buffer;
383
384 if (*_name)
385 return -EINVAL;
386
387 /* Empty name string if no material */
388 if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) {
389 buffer = kmalloc(1, GFP_KERNEL);
390 if (!buffer)
391 return -ENOMEM;
392 buffer[0] = 0;
393 goto done;
394 }
395
396 if (ctx->cn_size && ctx->o_size) {
397 /* Consider combining O and CN, but use only the CN if it is
398 * prefixed by the O, or a significant portion thereof.
399 */
400 namesize = ctx->cn_size;
401 name = data + ctx->cn_offset;
402 if (ctx->cn_size >= ctx->o_size &&
403 memcmp(data + ctx->cn_offset, data + ctx->o_offset,
404 ctx->o_size) == 0)
405 goto single_component;
406 if (ctx->cn_size >= 7 &&
407 ctx->o_size >= 7 &&
408 memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0)
409 goto single_component;
410
411 buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1,
412 GFP_KERNEL);
413 if (!buffer)
414 return -ENOMEM;
415
416 memcpy(buffer,
417 data + ctx->o_offset, ctx->o_size);
418 buffer[ctx->o_size + 0] = ':';
419 buffer[ctx->o_size + 1] = ' ';
420 memcpy(buffer + ctx->o_size + 2,
421 data + ctx->cn_offset, ctx->cn_size);
422 buffer[ctx->o_size + 2 + ctx->cn_size] = 0;
423 goto done;
424
425 } else if (ctx->cn_size) {
426 namesize = ctx->cn_size;
427 name = data + ctx->cn_offset;
428 } else if (ctx->o_size) {
429 namesize = ctx->o_size;
430 name = data + ctx->o_offset;
431 } else {
432 namesize = ctx->email_size;
433 name = data + ctx->email_offset;
434 }
435
436single_component:
437 buffer = kmalloc(namesize + 1, GFP_KERNEL);
438 if (!buffer)
439 return -ENOMEM;
440 memcpy(buffer, name, namesize);
441 buffer[namesize] = 0;
442
443done:
444 *_name = buffer;
445 ctx->cn_size = 0;
446 ctx->o_size = 0;
447 ctx->email_size = 0;
448 return 0;
449}
450
451int x509_note_issuer(void *context, size_t hdrlen,
452 unsigned char tag,
453 const void *value, size_t vlen)
454{
455 struct x509_parse_context *ctx = context;
456 struct asymmetric_key_id *kid;
457
458 ctx->cert->raw_issuer = value;
459 ctx->cert->raw_issuer_size = vlen;
460
461 if (!ctx->cert->sig->auth_ids[2]) {
462 kid = asymmetric_key_generate_id(value, vlen, "", 0);
463 if (IS_ERR(kid))
464 return PTR_ERR(kid);
465 ctx->cert->sig->auth_ids[2] = kid;
466 }
467
468 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen);
469}
470
471int x509_note_subject(void *context, size_t hdrlen,
472 unsigned char tag,
473 const void *value, size_t vlen)
474{
475 struct x509_parse_context *ctx = context;
476 ctx->cert->raw_subject = value;
477 ctx->cert->raw_subject_size = vlen;
478 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen);
479}
480
481/*
482 * Extract the parameters for the public key
483 */
484int x509_note_params(void *context, size_t hdrlen,
485 unsigned char tag,
486 const void *value, size_t vlen)
487{
488 struct x509_parse_context *ctx = context;
489
490 /*
491 * AlgorithmIdentifier is used three times in the x509, we should skip
492 * first and ignore third, using second one which is after subject and
493 * before subjectPublicKey.
494 */
495 if (!ctx->cert->raw_subject || ctx->key)
496 return 0;
497 ctx->params = value - hdrlen;
498 ctx->params_size = vlen + hdrlen;
499 return 0;
500}
501
502/*
503 * Extract the data for the public key algorithm
504 */
505int x509_extract_key_data(void *context, size_t hdrlen,
506 unsigned char tag,
507 const void *value, size_t vlen)
508{
509 struct x509_parse_context *ctx = context;
510 enum OID oid;
511
512 ctx->key_algo = ctx->last_oid;
513 switch (ctx->last_oid) {
514 case OID_rsaEncryption:
515 ctx->cert->pub->pkey_algo = "rsa";
516 break;
517 case OID_gost2012PKey256:
518 case OID_gost2012PKey512:
519 ctx->cert->pub->pkey_algo = "ecrdsa";
520 break;
521 case OID_sm2:
522 ctx->cert->pub->pkey_algo = "sm2";
523 break;
524 case OID_id_ecPublicKey:
525 if (parse_OID(ctx->params, ctx->params_size, &oid) != 0)
526 return -EBADMSG;
527
528 switch (oid) {
529 case OID_sm2:
530 ctx->cert->pub->pkey_algo = "sm2";
531 break;
532 case OID_id_prime192v1:
533 ctx->cert->pub->pkey_algo = "ecdsa-nist-p192";
534 break;
535 case OID_id_prime256v1:
536 ctx->cert->pub->pkey_algo = "ecdsa-nist-p256";
537 break;
538 case OID_id_ansip384r1:
539 ctx->cert->pub->pkey_algo = "ecdsa-nist-p384";
540 break;
541 default:
542 return -ENOPKG;
543 }
544 break;
545 default:
546 return -ENOPKG;
547 }
548
549 /* Discard the BIT STRING metadata */
550 if (vlen < 1 || *(const u8 *)value != 0)
551 return -EBADMSG;
552 ctx->key = value + 1;
553 ctx->key_size = vlen - 1;
554 return 0;
555}
556
557/* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */
558#define SEQ_TAG_KEYID (ASN1_CONT << 6)
559
560/*
561 * Process certificate extensions that are used to qualify the certificate.
562 */
563int x509_process_extension(void *context, size_t hdrlen,
564 unsigned char tag,
565 const void *value, size_t vlen)
566{
567 struct x509_parse_context *ctx = context;
568 struct asymmetric_key_id *kid;
569 const unsigned char *v = value;
570
571 pr_debug("Extension: %u\n", ctx->last_oid);
572
573 if (ctx->last_oid == OID_subjectKeyIdentifier) {
574 /* Get hold of the key fingerprint */
575 if (ctx->cert->skid || vlen < 3)
576 return -EBADMSG;
577 if (v[0] != ASN1_OTS || v[1] != vlen - 2)
578 return -EBADMSG;
579 v += 2;
580 vlen -= 2;
581
582 ctx->cert->raw_skid_size = vlen;
583 ctx->cert->raw_skid = v;
584 kid = asymmetric_key_generate_id(v, vlen, "", 0);
585 if (IS_ERR(kid))
586 return PTR_ERR(kid);
587 ctx->cert->skid = kid;
588 pr_debug("subjkeyid %*phN\n", kid->len, kid->data);
589 return 0;
590 }
591
592 if (ctx->last_oid == OID_keyUsage) {
593 /*
594 * Get hold of the keyUsage bit string
595 * v[1] is the encoding size
596 * (Expect either 0x02 or 0x03, making it 1 or 2 bytes)
597 * v[2] is the number of unused bits in the bit string
598 * (If >= 3 keyCertSign is missing when v[1] = 0x02)
599 * v[3] and possibly v[4] contain the bit string
600 *
601 * From RFC 5280 4.2.1.3:
602 * 0x04 is where keyCertSign lands in this bit string
603 * 0x80 is where digitalSignature lands in this bit string
604 */
605 if (v[0] != ASN1_BTS)
606 return -EBADMSG;
607 if (vlen < 4)
608 return -EBADMSG;
609 if (v[2] >= 8)
610 return -EBADMSG;
611 if (v[3] & 0x80)
612 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_DIGITALSIG;
613 if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04))
614 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
615 else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04))
616 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
617 return 0;
618 }
619
620 if (ctx->last_oid == OID_authorityKeyIdentifier) {
621 /* Get hold of the CA key fingerprint */
622 ctx->raw_akid = v;
623 ctx->raw_akid_size = vlen;
624 return 0;
625 }
626
627 if (ctx->last_oid == OID_basicConstraints) {
628 /*
629 * Get hold of the basicConstraints
630 * v[1] is the encoding size
631 * (Expect 0x2 or greater, making it 1 or more bytes)
632 * v[2] is the encoding type
633 * (Expect an ASN1_BOOL for the CA)
634 * v[3] is the contents of the ASN1_BOOL
635 * (Expect 1 if the CA is TRUE)
636 * vlen should match the entire extension size
637 */
638 if (v[0] != (ASN1_CONS_BIT | ASN1_SEQ))
639 return -EBADMSG;
640 if (vlen < 2)
641 return -EBADMSG;
642 if (v[1] != vlen - 2)
643 return -EBADMSG;
644 if (vlen >= 4 && v[1] != 0 && v[2] == ASN1_BOOL && v[3] == 1)
645 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_CA;
646 return 0;
647 }
648
649 return 0;
650}
651
652/**
653 * x509_decode_time - Decode an X.509 time ASN.1 object
654 * @_t: The time to fill in
655 * @hdrlen: The length of the object header
656 * @tag: The object tag
657 * @value: The object value
658 * @vlen: The size of the object value
659 *
660 * Decode an ASN.1 universal time or generalised time field into a struct the
661 * kernel can handle and check it for validity. The time is decoded thus:
662 *
663 * [RFC5280 ยง4.1.2.5]
664 * CAs conforming to this profile MUST always encode certificate validity
665 * dates through the year 2049 as UTCTime; certificate validity dates in
666 * 2050 or later MUST be encoded as GeneralizedTime. Conforming
667 * applications MUST be able to process validity dates that are encoded in
668 * either UTCTime or GeneralizedTime.
669 */
670int x509_decode_time(time64_t *_t, size_t hdrlen,
671 unsigned char tag,
672 const unsigned char *value, size_t vlen)
673{
674 static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30,
675 31, 31, 30, 31, 30, 31 };
676 const unsigned char *p = value;
677 unsigned year, mon, day, hour, min, sec, mon_len;
678
679#define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; })
680#define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
681
682 if (tag == ASN1_UNITIM) {
683 /* UTCTime: YYMMDDHHMMSSZ */
684 if (vlen != 13)
685 goto unsupported_time;
686 year = DD2bin(p);
687 if (year >= 50)
688 year += 1900;
689 else
690 year += 2000;
691 } else if (tag == ASN1_GENTIM) {
692 /* GenTime: YYYYMMDDHHMMSSZ */
693 if (vlen != 15)
694 goto unsupported_time;
695 year = DD2bin(p) * 100 + DD2bin(p);
696 if (year >= 1950 && year <= 2049)
697 goto invalid_time;
698 } else {
699 goto unsupported_time;
700 }
701
702 mon = DD2bin(p);
703 day = DD2bin(p);
704 hour = DD2bin(p);
705 min = DD2bin(p);
706 sec = DD2bin(p);
707
708 if (*p != 'Z')
709 goto unsupported_time;
710
711 if (year < 1970 ||
712 mon < 1 || mon > 12)
713 goto invalid_time;
714
715 mon_len = month_lengths[mon - 1];
716 if (mon == 2) {
717 if (year % 4 == 0) {
718 mon_len = 29;
719 if (year % 100 == 0) {
720 mon_len = 28;
721 if (year % 400 == 0)
722 mon_len = 29;
723 }
724 }
725 }
726
727 if (day < 1 || day > mon_len ||
728 hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
729 min > 59 ||
730 sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
731 goto invalid_time;
732
733 *_t = mktime64(year, mon, day, hour, min, sec);
734 return 0;
735
736unsupported_time:
737 pr_debug("Got unsupported time [tag %02x]: '%*phN'\n",
738 tag, (int)vlen, value);
739 return -EBADMSG;
740invalid_time:
741 pr_debug("Got invalid time [tag %02x]: '%*phN'\n",
742 tag, (int)vlen, value);
743 return -EBADMSG;
744}
745EXPORT_SYMBOL_GPL(x509_decode_time);
746
747int x509_note_not_before(void *context, size_t hdrlen,
748 unsigned char tag,
749 const void *value, size_t vlen)
750{
751 struct x509_parse_context *ctx = context;
752 return x509_decode_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
753}
754
755int x509_note_not_after(void *context, size_t hdrlen,
756 unsigned char tag,
757 const void *value, size_t vlen)
758{
759 struct x509_parse_context *ctx = context;
760 return x509_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
761}
762
763/*
764 * Note a key identifier-based AuthorityKeyIdentifier
765 */
766int x509_akid_note_kid(void *context, size_t hdrlen,
767 unsigned char tag,
768 const void *value, size_t vlen)
769{
770 struct x509_parse_context *ctx = context;
771 struct asymmetric_key_id *kid;
772
773 pr_debug("AKID: keyid: %*phN\n", (int)vlen, value);
774
775 if (ctx->cert->sig->auth_ids[1])
776 return 0;
777
778 kid = asymmetric_key_generate_id(value, vlen, "", 0);
779 if (IS_ERR(kid))
780 return PTR_ERR(kid);
781 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
782 ctx->cert->sig->auth_ids[1] = kid;
783 return 0;
784}
785
786/*
787 * Note a directoryName in an AuthorityKeyIdentifier
788 */
789int x509_akid_note_name(void *context, size_t hdrlen,
790 unsigned char tag,
791 const void *value, size_t vlen)
792{
793 struct x509_parse_context *ctx = context;
794
795 pr_debug("AKID: name: %*phN\n", (int)vlen, value);
796
797 ctx->akid_raw_issuer = value;
798 ctx->akid_raw_issuer_size = vlen;
799 return 0;
800}
801
802/*
803 * Note a serial number in an AuthorityKeyIdentifier
804 */
805int x509_akid_note_serial(void *context, size_t hdrlen,
806 unsigned char tag,
807 const void *value, size_t vlen)
808{
809 struct x509_parse_context *ctx = context;
810 struct asymmetric_key_id *kid;
811
812 pr_debug("AKID: serial: %*phN\n", (int)vlen, value);
813
814 if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0])
815 return 0;
816
817 kid = asymmetric_key_generate_id(value,
818 vlen,
819 ctx->akid_raw_issuer,
820 ctx->akid_raw_issuer_size);
821 if (IS_ERR(kid))
822 return PTR_ERR(kid);
823
824 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
825 ctx->cert->sig->auth_ids[0] = kid;
826 return 0;
827}