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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 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}
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}