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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 *cert_start; /* Start of cert content */
23 const void *key; /* Key data */
24 size_t key_size; /* Size of key data */
25 const void *params; /* Key parameters */
26 size_t params_size; /* Size of key parameters */
27 enum OID key_algo; /* Public key algorithm */
28 enum OID last_oid; /* Last OID encountered */
29 enum OID algo_oid; /* Algorithm OID */
30 unsigned char nr_mpi; /* Number of MPIs stored */
31 u8 o_size; /* Size of organizationName (O) */
32 u8 cn_size; /* Size of commonName (CN) */
33 u8 email_size; /* Size of emailAddress */
34 u16 o_offset; /* Offset of organizationName (O) */
35 u16 cn_offset; /* Offset of commonName (CN) */
36 u16 email_offset; /* Offset of emailAddress */
37 unsigned raw_akid_size;
38 const void *raw_akid; /* Raw authorityKeyId in ASN.1 */
39 const void *akid_raw_issuer; /* Raw directoryName in authorityKeyId */
40 unsigned akid_raw_issuer_size;
41};
42
43/*
44 * Free an X.509 certificate
45 */
46void x509_free_certificate(struct x509_certificate *cert)
47{
48 if (cert) {
49 public_key_free(cert->pub);
50 public_key_signature_free(cert->sig);
51 kfree(cert->issuer);
52 kfree(cert->subject);
53 kfree(cert->id);
54 kfree(cert->skid);
55 kfree(cert);
56 }
57}
58EXPORT_SYMBOL_GPL(x509_free_certificate);
59
60/*
61 * Parse an X.509 certificate
62 */
63struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
64{
65 struct x509_certificate *cert;
66 struct x509_parse_context *ctx;
67 struct asymmetric_key_id *kid;
68 long ret;
69
70 ret = -ENOMEM;
71 cert = kzalloc(sizeof(struct x509_certificate), GFP_KERNEL);
72 if (!cert)
73 goto error_no_cert;
74 cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);
75 if (!cert->pub)
76 goto error_no_ctx;
77 cert->sig = kzalloc(sizeof(struct public_key_signature), GFP_KERNEL);
78 if (!cert->sig)
79 goto error_no_ctx;
80 ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL);
81 if (!ctx)
82 goto error_no_ctx;
83
84 ctx->cert = cert;
85 ctx->data = (unsigned long)data;
86
87 /* Attempt to decode the certificate */
88 ret = asn1_ber_decoder(&x509_decoder, ctx, data, datalen);
89 if (ret < 0)
90 goto error_decode;
91
92 /* Decode the AuthorityKeyIdentifier */
93 if (ctx->raw_akid) {
94 pr_devel("AKID: %u %*phN\n",
95 ctx->raw_akid_size, ctx->raw_akid_size, ctx->raw_akid);
96 ret = asn1_ber_decoder(&x509_akid_decoder, ctx,
97 ctx->raw_akid, ctx->raw_akid_size);
98 if (ret < 0) {
99 pr_warn("Couldn't decode AuthKeyIdentifier\n");
100 goto error_decode;
101 }
102 }
103
104 ret = -ENOMEM;
105 cert->pub->key = kmemdup(ctx->key, ctx->key_size, GFP_KERNEL);
106 if (!cert->pub->key)
107 goto error_decode;
108
109 cert->pub->keylen = ctx->key_size;
110
111 cert->pub->params = kmemdup(ctx->params, ctx->params_size, GFP_KERNEL);
112 if (!cert->pub->params)
113 goto error_decode;
114
115 cert->pub->paramlen = ctx->params_size;
116 cert->pub->algo = ctx->key_algo;
117
118 /* Grab the signature bits */
119 ret = x509_get_sig_params(cert);
120 if (ret < 0)
121 goto error_decode;
122
123 /* Generate cert issuer + serial number key ID */
124 kid = asymmetric_key_generate_id(cert->raw_serial,
125 cert->raw_serial_size,
126 cert->raw_issuer,
127 cert->raw_issuer_size);
128 if (IS_ERR(kid)) {
129 ret = PTR_ERR(kid);
130 goto error_decode;
131 }
132 cert->id = kid;
133
134 /* Detect self-signed certificates */
135 ret = x509_check_for_self_signed(cert);
136 if (ret < 0)
137 goto error_decode;
138
139 kfree(ctx);
140 return cert;
141
142error_decode:
143 kfree(ctx);
144error_no_ctx:
145 x509_free_certificate(cert);
146error_no_cert:
147 return ERR_PTR(ret);
148}
149EXPORT_SYMBOL_GPL(x509_cert_parse);
150
151/*
152 * Note an OID when we find one for later processing when we know how
153 * to interpret it.
154 */
155int x509_note_OID(void *context, size_t hdrlen,
156 unsigned char tag,
157 const void *value, size_t vlen)
158{
159 struct x509_parse_context *ctx = context;
160
161 ctx->last_oid = look_up_OID(value, vlen);
162 if (ctx->last_oid == OID__NR) {
163 char buffer[50];
164 sprint_oid(value, vlen, buffer, sizeof(buffer));
165 pr_debug("Unknown OID: [%lu] %s\n",
166 (unsigned long)value - ctx->data, buffer);
167 }
168 return 0;
169}
170
171/*
172 * Save the position of the TBS data so that we can check the signature over it
173 * later.
174 */
175int x509_note_tbs_certificate(void *context, size_t hdrlen,
176 unsigned char tag,
177 const void *value, size_t vlen)
178{
179 struct x509_parse_context *ctx = context;
180
181 pr_debug("x509_note_tbs_certificate(,%zu,%02x,%ld,%zu)!\n",
182 hdrlen, tag, (unsigned long)value - ctx->data, vlen);
183
184 ctx->cert->tbs = value - hdrlen;
185 ctx->cert->tbs_size = vlen + hdrlen;
186 return 0;
187}
188
189/*
190 * Record the public key algorithm
191 */
192int x509_note_pkey_algo(void *context, size_t hdrlen,
193 unsigned char tag,
194 const void *value, size_t vlen)
195{
196 struct x509_parse_context *ctx = context;
197
198 pr_debug("PubKey Algo: %u\n", ctx->last_oid);
199
200 switch (ctx->last_oid) {
201 case OID_md2WithRSAEncryption:
202 case OID_md3WithRSAEncryption:
203 default:
204 return -ENOPKG; /* Unsupported combination */
205
206 case OID_md4WithRSAEncryption:
207 ctx->cert->sig->hash_algo = "md4";
208 goto rsa_pkcs1;
209
210 case OID_sha1WithRSAEncryption:
211 ctx->cert->sig->hash_algo = "sha1";
212 goto rsa_pkcs1;
213
214 case OID_sha256WithRSAEncryption:
215 ctx->cert->sig->hash_algo = "sha256";
216 goto rsa_pkcs1;
217
218 case OID_sha384WithRSAEncryption:
219 ctx->cert->sig->hash_algo = "sha384";
220 goto rsa_pkcs1;
221
222 case OID_sha512WithRSAEncryption:
223 ctx->cert->sig->hash_algo = "sha512";
224 goto rsa_pkcs1;
225
226 case OID_sha224WithRSAEncryption:
227 ctx->cert->sig->hash_algo = "sha224";
228 goto rsa_pkcs1;
229
230 case OID_gost2012Signature256:
231 ctx->cert->sig->hash_algo = "streebog256";
232 goto ecrdsa;
233
234 case OID_gost2012Signature512:
235 ctx->cert->sig->hash_algo = "streebog512";
236 goto ecrdsa;
237 }
238
239rsa_pkcs1:
240 ctx->cert->sig->pkey_algo = "rsa";
241 ctx->cert->sig->encoding = "pkcs1";
242 ctx->algo_oid = ctx->last_oid;
243 return 0;
244ecrdsa:
245 ctx->cert->sig->pkey_algo = "ecrdsa";
246 ctx->cert->sig->encoding = "raw";
247 ctx->algo_oid = ctx->last_oid;
248 return 0;
249}
250
251/*
252 * Note the whereabouts and type of the signature.
253 */
254int x509_note_signature(void *context, size_t hdrlen,
255 unsigned char tag,
256 const void *value, size_t vlen)
257{
258 struct x509_parse_context *ctx = context;
259
260 pr_debug("Signature type: %u size %zu\n", ctx->last_oid, vlen);
261
262 if (ctx->last_oid != ctx->algo_oid) {
263 pr_warn("Got cert with pkey (%u) and sig (%u) algorithm OIDs\n",
264 ctx->algo_oid, ctx->last_oid);
265 return -EINVAL;
266 }
267
268 if (strcmp(ctx->cert->sig->pkey_algo, "rsa") == 0 ||
269 strcmp(ctx->cert->sig->pkey_algo, "ecrdsa") == 0) {
270 /* Discard the BIT STRING metadata */
271 if (vlen < 1 || *(const u8 *)value != 0)
272 return -EBADMSG;
273
274 value++;
275 vlen--;
276 }
277
278 ctx->cert->raw_sig = value;
279 ctx->cert->raw_sig_size = vlen;
280 return 0;
281}
282
283/*
284 * Note the certificate serial number
285 */
286int x509_note_serial(void *context, size_t hdrlen,
287 unsigned char tag,
288 const void *value, size_t vlen)
289{
290 struct x509_parse_context *ctx = context;
291 ctx->cert->raw_serial = value;
292 ctx->cert->raw_serial_size = vlen;
293 return 0;
294}
295
296/*
297 * Note some of the name segments from which we'll fabricate a name.
298 */
299int x509_extract_name_segment(void *context, size_t hdrlen,
300 unsigned char tag,
301 const void *value, size_t vlen)
302{
303 struct x509_parse_context *ctx = context;
304
305 switch (ctx->last_oid) {
306 case OID_commonName:
307 ctx->cn_size = vlen;
308 ctx->cn_offset = (unsigned long)value - ctx->data;
309 break;
310 case OID_organizationName:
311 ctx->o_size = vlen;
312 ctx->o_offset = (unsigned long)value - ctx->data;
313 break;
314 case OID_email_address:
315 ctx->email_size = vlen;
316 ctx->email_offset = (unsigned long)value - ctx->data;
317 break;
318 default:
319 break;
320 }
321
322 return 0;
323}
324
325/*
326 * Fabricate and save the issuer and subject names
327 */
328static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen,
329 unsigned char tag,
330 char **_name, size_t vlen)
331{
332 const void *name, *data = (const void *)ctx->data;
333 size_t namesize;
334 char *buffer;
335
336 if (*_name)
337 return -EINVAL;
338
339 /* Empty name string if no material */
340 if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) {
341 buffer = kmalloc(1, GFP_KERNEL);
342 if (!buffer)
343 return -ENOMEM;
344 buffer[0] = 0;
345 goto done;
346 }
347
348 if (ctx->cn_size && ctx->o_size) {
349 /* Consider combining O and CN, but use only the CN if it is
350 * prefixed by the O, or a significant portion thereof.
351 */
352 namesize = ctx->cn_size;
353 name = data + ctx->cn_offset;
354 if (ctx->cn_size >= ctx->o_size &&
355 memcmp(data + ctx->cn_offset, data + ctx->o_offset,
356 ctx->o_size) == 0)
357 goto single_component;
358 if (ctx->cn_size >= 7 &&
359 ctx->o_size >= 7 &&
360 memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0)
361 goto single_component;
362
363 buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1,
364 GFP_KERNEL);
365 if (!buffer)
366 return -ENOMEM;
367
368 memcpy(buffer,
369 data + ctx->o_offset, ctx->o_size);
370 buffer[ctx->o_size + 0] = ':';
371 buffer[ctx->o_size + 1] = ' ';
372 memcpy(buffer + ctx->o_size + 2,
373 data + ctx->cn_offset, ctx->cn_size);
374 buffer[ctx->o_size + 2 + ctx->cn_size] = 0;
375 goto done;
376
377 } else if (ctx->cn_size) {
378 namesize = ctx->cn_size;
379 name = data + ctx->cn_offset;
380 } else if (ctx->o_size) {
381 namesize = ctx->o_size;
382 name = data + ctx->o_offset;
383 } else {
384 namesize = ctx->email_size;
385 name = data + ctx->email_offset;
386 }
387
388single_component:
389 buffer = kmalloc(namesize + 1, GFP_KERNEL);
390 if (!buffer)
391 return -ENOMEM;
392 memcpy(buffer, name, namesize);
393 buffer[namesize] = 0;
394
395done:
396 *_name = buffer;
397 ctx->cn_size = 0;
398 ctx->o_size = 0;
399 ctx->email_size = 0;
400 return 0;
401}
402
403int x509_note_issuer(void *context, size_t hdrlen,
404 unsigned char tag,
405 const void *value, size_t vlen)
406{
407 struct x509_parse_context *ctx = context;
408 ctx->cert->raw_issuer = value;
409 ctx->cert->raw_issuer_size = vlen;
410 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen);
411}
412
413int x509_note_subject(void *context, size_t hdrlen,
414 unsigned char tag,
415 const void *value, size_t vlen)
416{
417 struct x509_parse_context *ctx = context;
418 ctx->cert->raw_subject = value;
419 ctx->cert->raw_subject_size = vlen;
420 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen);
421}
422
423/*
424 * Extract the parameters for the public key
425 */
426int x509_note_params(void *context, size_t hdrlen,
427 unsigned char tag,
428 const void *value, size_t vlen)
429{
430 struct x509_parse_context *ctx = context;
431
432 /*
433 * AlgorithmIdentifier is used three times in the x509, we should skip
434 * first and ignore third, using second one which is after subject and
435 * before subjectPublicKey.
436 */
437 if (!ctx->cert->raw_subject || ctx->key)
438 return 0;
439 ctx->params = value - hdrlen;
440 ctx->params_size = vlen + hdrlen;
441 return 0;
442}
443
444/*
445 * Extract the data for the public key algorithm
446 */
447int x509_extract_key_data(void *context, size_t hdrlen,
448 unsigned char tag,
449 const void *value, size_t vlen)
450{
451 struct x509_parse_context *ctx = context;
452
453 ctx->key_algo = ctx->last_oid;
454 if (ctx->last_oid == OID_rsaEncryption)
455 ctx->cert->pub->pkey_algo = "rsa";
456 else if (ctx->last_oid == OID_gost2012PKey256 ||
457 ctx->last_oid == OID_gost2012PKey512)
458 ctx->cert->pub->pkey_algo = "ecrdsa";
459 else
460 return -ENOPKG;
461
462 /* Discard the BIT STRING metadata */
463 if (vlen < 1 || *(const u8 *)value != 0)
464 return -EBADMSG;
465 ctx->key = value + 1;
466 ctx->key_size = vlen - 1;
467 return 0;
468}
469
470/* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */
471#define SEQ_TAG_KEYID (ASN1_CONT << 6)
472
473/*
474 * Process certificate extensions that are used to qualify the certificate.
475 */
476int x509_process_extension(void *context, size_t hdrlen,
477 unsigned char tag,
478 const void *value, size_t vlen)
479{
480 struct x509_parse_context *ctx = context;
481 struct asymmetric_key_id *kid;
482 const unsigned char *v = value;
483
484 pr_debug("Extension: %u\n", ctx->last_oid);
485
486 if (ctx->last_oid == OID_subjectKeyIdentifier) {
487 /* Get hold of the key fingerprint */
488 if (ctx->cert->skid || vlen < 3)
489 return -EBADMSG;
490 if (v[0] != ASN1_OTS || v[1] != vlen - 2)
491 return -EBADMSG;
492 v += 2;
493 vlen -= 2;
494
495 ctx->cert->raw_skid_size = vlen;
496 ctx->cert->raw_skid = v;
497 kid = asymmetric_key_generate_id(v, vlen, "", 0);
498 if (IS_ERR(kid))
499 return PTR_ERR(kid);
500 ctx->cert->skid = kid;
501 pr_debug("subjkeyid %*phN\n", kid->len, kid->data);
502 return 0;
503 }
504
505 if (ctx->last_oid == OID_authorityKeyIdentifier) {
506 /* Get hold of the CA key fingerprint */
507 ctx->raw_akid = v;
508 ctx->raw_akid_size = vlen;
509 return 0;
510 }
511
512 return 0;
513}
514
515/**
516 * x509_decode_time - Decode an X.509 time ASN.1 object
517 * @_t: The time to fill in
518 * @hdrlen: The length of the object header
519 * @tag: The object tag
520 * @value: The object value
521 * @vlen: The size of the object value
522 *
523 * Decode an ASN.1 universal time or generalised time field into a struct the
524 * kernel can handle and check it for validity. The time is decoded thus:
525 *
526 * [RFC5280 ยง4.1.2.5]
527 * CAs conforming to this profile MUST always encode certificate validity
528 * dates through the year 2049 as UTCTime; certificate validity dates in
529 * 2050 or later MUST be encoded as GeneralizedTime. Conforming
530 * applications MUST be able to process validity dates that are encoded in
531 * either UTCTime or GeneralizedTime.
532 */
533int x509_decode_time(time64_t *_t, size_t hdrlen,
534 unsigned char tag,
535 const unsigned char *value, size_t vlen)
536{
537 static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30,
538 31, 31, 30, 31, 30, 31 };
539 const unsigned char *p = value;
540 unsigned year, mon, day, hour, min, sec, mon_len;
541
542#define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; })
543#define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
544
545 if (tag == ASN1_UNITIM) {
546 /* UTCTime: YYMMDDHHMMSSZ */
547 if (vlen != 13)
548 goto unsupported_time;
549 year = DD2bin(p);
550 if (year >= 50)
551 year += 1900;
552 else
553 year += 2000;
554 } else if (tag == ASN1_GENTIM) {
555 /* GenTime: YYYYMMDDHHMMSSZ */
556 if (vlen != 15)
557 goto unsupported_time;
558 year = DD2bin(p) * 100 + DD2bin(p);
559 if (year >= 1950 && year <= 2049)
560 goto invalid_time;
561 } else {
562 goto unsupported_time;
563 }
564
565 mon = DD2bin(p);
566 day = DD2bin(p);
567 hour = DD2bin(p);
568 min = DD2bin(p);
569 sec = DD2bin(p);
570
571 if (*p != 'Z')
572 goto unsupported_time;
573
574 if (year < 1970 ||
575 mon < 1 || mon > 12)
576 goto invalid_time;
577
578 mon_len = month_lengths[mon - 1];
579 if (mon == 2) {
580 if (year % 4 == 0) {
581 mon_len = 29;
582 if (year % 100 == 0) {
583 mon_len = 28;
584 if (year % 400 == 0)
585 mon_len = 29;
586 }
587 }
588 }
589
590 if (day < 1 || day > mon_len ||
591 hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
592 min > 59 ||
593 sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
594 goto invalid_time;
595
596 *_t = mktime64(year, mon, day, hour, min, sec);
597 return 0;
598
599unsupported_time:
600 pr_debug("Got unsupported time [tag %02x]: '%*phN'\n",
601 tag, (int)vlen, value);
602 return -EBADMSG;
603invalid_time:
604 pr_debug("Got invalid time [tag %02x]: '%*phN'\n",
605 tag, (int)vlen, value);
606 return -EBADMSG;
607}
608EXPORT_SYMBOL_GPL(x509_decode_time);
609
610int x509_note_not_before(void *context, size_t hdrlen,
611 unsigned char tag,
612 const void *value, size_t vlen)
613{
614 struct x509_parse_context *ctx = context;
615 return x509_decode_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
616}
617
618int x509_note_not_after(void *context, size_t hdrlen,
619 unsigned char tag,
620 const void *value, size_t vlen)
621{
622 struct x509_parse_context *ctx = context;
623 return x509_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
624}
625
626/*
627 * Note a key identifier-based AuthorityKeyIdentifier
628 */
629int x509_akid_note_kid(void *context, size_t hdrlen,
630 unsigned char tag,
631 const void *value, size_t vlen)
632{
633 struct x509_parse_context *ctx = context;
634 struct asymmetric_key_id *kid;
635
636 pr_debug("AKID: keyid: %*phN\n", (int)vlen, value);
637
638 if (ctx->cert->sig->auth_ids[1])
639 return 0;
640
641 kid = asymmetric_key_generate_id(value, vlen, "", 0);
642 if (IS_ERR(kid))
643 return PTR_ERR(kid);
644 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
645 ctx->cert->sig->auth_ids[1] = kid;
646 return 0;
647}
648
649/*
650 * Note a directoryName in an AuthorityKeyIdentifier
651 */
652int x509_akid_note_name(void *context, size_t hdrlen,
653 unsigned char tag,
654 const void *value, size_t vlen)
655{
656 struct x509_parse_context *ctx = context;
657
658 pr_debug("AKID: name: %*phN\n", (int)vlen, value);
659
660 ctx->akid_raw_issuer = value;
661 ctx->akid_raw_issuer_size = vlen;
662 return 0;
663}
664
665/*
666 * Note a serial number in an AuthorityKeyIdentifier
667 */
668int x509_akid_note_serial(void *context, size_t hdrlen,
669 unsigned char tag,
670 const void *value, size_t vlen)
671{
672 struct x509_parse_context *ctx = context;
673 struct asymmetric_key_id *kid;
674
675 pr_debug("AKID: serial: %*phN\n", (int)vlen, value);
676
677 if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0])
678 return 0;
679
680 kid = asymmetric_key_generate_id(value,
681 vlen,
682 ctx->akid_raw_issuer,
683 ctx->akid_raw_issuer_size);
684 if (IS_ERR(kid))
685 return PTR_ERR(kid);
686
687 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
688 ctx->cert->sig->auth_ids[0] = kid;
689 return 0;
690}
1/* X.509 certificate parser
2 *
3 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#define pr_fmt(fmt) "X.509: "fmt
13#include <linux/kernel.h>
14#include <linux/export.h>
15#include <linux/slab.h>
16#include <linux/err.h>
17#include <linux/oid_registry.h>
18#include <crypto/public_key.h>
19#include "x509_parser.h"
20#include "x509.asn1.h"
21#include "x509_akid.asn1.h"
22
23struct x509_parse_context {
24 struct x509_certificate *cert; /* Certificate being constructed */
25 unsigned long data; /* Start of data */
26 const void *cert_start; /* Start of cert content */
27 const void *key; /* Key data */
28 size_t key_size; /* Size of key data */
29 enum OID last_oid; /* Last OID encountered */
30 enum OID algo_oid; /* Algorithm OID */
31 unsigned char nr_mpi; /* Number of MPIs stored */
32 u8 o_size; /* Size of organizationName (O) */
33 u8 cn_size; /* Size of commonName (CN) */
34 u8 email_size; /* Size of emailAddress */
35 u16 o_offset; /* Offset of organizationName (O) */
36 u16 cn_offset; /* Offset of commonName (CN) */
37 u16 email_offset; /* Offset of emailAddress */
38 unsigned raw_akid_size;
39 const void *raw_akid; /* Raw authorityKeyId in ASN.1 */
40 const void *akid_raw_issuer; /* Raw directoryName in authorityKeyId */
41 unsigned akid_raw_issuer_size;
42};
43
44/*
45 * Free an X.509 certificate
46 */
47void x509_free_certificate(struct x509_certificate *cert)
48{
49 if (cert) {
50 public_key_free(cert->pub);
51 public_key_signature_free(cert->sig);
52 kfree(cert->issuer);
53 kfree(cert->subject);
54 kfree(cert->id);
55 kfree(cert->skid);
56 kfree(cert);
57 }
58}
59EXPORT_SYMBOL_GPL(x509_free_certificate);
60
61/*
62 * Parse an X.509 certificate
63 */
64struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
65{
66 struct x509_certificate *cert;
67 struct x509_parse_context *ctx;
68 struct asymmetric_key_id *kid;
69 long ret;
70
71 ret = -ENOMEM;
72 cert = kzalloc(sizeof(struct x509_certificate), GFP_KERNEL);
73 if (!cert)
74 goto error_no_cert;
75 cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);
76 if (!cert->pub)
77 goto error_no_ctx;
78 cert->sig = kzalloc(sizeof(struct public_key_signature), GFP_KERNEL);
79 if (!cert->sig)
80 goto error_no_ctx;
81 ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL);
82 if (!ctx)
83 goto error_no_ctx;
84
85 ctx->cert = cert;
86 ctx->data = (unsigned long)data;
87
88 /* Attempt to decode the certificate */
89 ret = asn1_ber_decoder(&x509_decoder, ctx, data, datalen);
90 if (ret < 0)
91 goto error_decode;
92
93 /* Decode the AuthorityKeyIdentifier */
94 if (ctx->raw_akid) {
95 pr_devel("AKID: %u %*phN\n",
96 ctx->raw_akid_size, ctx->raw_akid_size, ctx->raw_akid);
97 ret = asn1_ber_decoder(&x509_akid_decoder, ctx,
98 ctx->raw_akid, ctx->raw_akid_size);
99 if (ret < 0) {
100 pr_warn("Couldn't decode AuthKeyIdentifier\n");
101 goto error_decode;
102 }
103 }
104
105 ret = -ENOMEM;
106 cert->pub->key = kmemdup(ctx->key, ctx->key_size, GFP_KERNEL);
107 if (!cert->pub->key)
108 goto error_decode;
109
110 cert->pub->keylen = ctx->key_size;
111
112 /* Grab the signature bits */
113 ret = x509_get_sig_params(cert);
114 if (ret < 0)
115 goto error_decode;
116
117 /* Generate cert issuer + serial number key ID */
118 kid = asymmetric_key_generate_id(cert->raw_serial,
119 cert->raw_serial_size,
120 cert->raw_issuer,
121 cert->raw_issuer_size);
122 if (IS_ERR(kid)) {
123 ret = PTR_ERR(kid);
124 goto error_decode;
125 }
126 cert->id = kid;
127
128 /* Detect self-signed certificates */
129 ret = x509_check_for_self_signed(cert);
130 if (ret < 0)
131 goto error_decode;
132
133 kfree(ctx);
134 return cert;
135
136error_decode:
137 kfree(ctx);
138error_no_ctx:
139 x509_free_certificate(cert);
140error_no_cert:
141 return ERR_PTR(ret);
142}
143EXPORT_SYMBOL_GPL(x509_cert_parse);
144
145/*
146 * Note an OID when we find one for later processing when we know how
147 * to interpret it.
148 */
149int x509_note_OID(void *context, size_t hdrlen,
150 unsigned char tag,
151 const void *value, size_t vlen)
152{
153 struct x509_parse_context *ctx = context;
154
155 ctx->last_oid = look_up_OID(value, vlen);
156 if (ctx->last_oid == OID__NR) {
157 char buffer[50];
158 sprint_oid(value, vlen, buffer, sizeof(buffer));
159 pr_debug("Unknown OID: [%lu] %s\n",
160 (unsigned long)value - ctx->data, buffer);
161 }
162 return 0;
163}
164
165/*
166 * Save the position of the TBS data so that we can check the signature over it
167 * later.
168 */
169int x509_note_tbs_certificate(void *context, size_t hdrlen,
170 unsigned char tag,
171 const void *value, size_t vlen)
172{
173 struct x509_parse_context *ctx = context;
174
175 pr_debug("x509_note_tbs_certificate(,%zu,%02x,%ld,%zu)!\n",
176 hdrlen, tag, (unsigned long)value - ctx->data, vlen);
177
178 ctx->cert->tbs = value - hdrlen;
179 ctx->cert->tbs_size = vlen + hdrlen;
180 return 0;
181}
182
183/*
184 * Record the public key algorithm
185 */
186int x509_note_pkey_algo(void *context, size_t hdrlen,
187 unsigned char tag,
188 const void *value, size_t vlen)
189{
190 struct x509_parse_context *ctx = context;
191
192 pr_debug("PubKey Algo: %u\n", ctx->last_oid);
193
194 switch (ctx->last_oid) {
195 case OID_md2WithRSAEncryption:
196 case OID_md3WithRSAEncryption:
197 default:
198 return -ENOPKG; /* Unsupported combination */
199
200 case OID_md4WithRSAEncryption:
201 ctx->cert->sig->hash_algo = "md4";
202 ctx->cert->sig->pkey_algo = "rsa";
203 break;
204
205 case OID_sha1WithRSAEncryption:
206 ctx->cert->sig->hash_algo = "sha1";
207 ctx->cert->sig->pkey_algo = "rsa";
208 break;
209
210 case OID_sha256WithRSAEncryption:
211 ctx->cert->sig->hash_algo = "sha256";
212 ctx->cert->sig->pkey_algo = "rsa";
213 break;
214
215 case OID_sha384WithRSAEncryption:
216 ctx->cert->sig->hash_algo = "sha384";
217 ctx->cert->sig->pkey_algo = "rsa";
218 break;
219
220 case OID_sha512WithRSAEncryption:
221 ctx->cert->sig->hash_algo = "sha512";
222 ctx->cert->sig->pkey_algo = "rsa";
223 break;
224
225 case OID_sha224WithRSAEncryption:
226 ctx->cert->sig->hash_algo = "sha224";
227 ctx->cert->sig->pkey_algo = "rsa";
228 break;
229 }
230
231 ctx->algo_oid = ctx->last_oid;
232 return 0;
233}
234
235/*
236 * Note the whereabouts and type of the signature.
237 */
238int x509_note_signature(void *context, size_t hdrlen,
239 unsigned char tag,
240 const void *value, size_t vlen)
241{
242 struct x509_parse_context *ctx = context;
243
244 pr_debug("Signature type: %u size %zu\n", ctx->last_oid, vlen);
245
246 if (ctx->last_oid != ctx->algo_oid) {
247 pr_warn("Got cert with pkey (%u) and sig (%u) algorithm OIDs\n",
248 ctx->algo_oid, ctx->last_oid);
249 return -EINVAL;
250 }
251
252 ctx->cert->raw_sig = value;
253 ctx->cert->raw_sig_size = vlen;
254 return 0;
255}
256
257/*
258 * Note the certificate serial number
259 */
260int x509_note_serial(void *context, size_t hdrlen,
261 unsigned char tag,
262 const void *value, size_t vlen)
263{
264 struct x509_parse_context *ctx = context;
265 ctx->cert->raw_serial = value;
266 ctx->cert->raw_serial_size = vlen;
267 return 0;
268}
269
270/*
271 * Note some of the name segments from which we'll fabricate a name.
272 */
273int x509_extract_name_segment(void *context, size_t hdrlen,
274 unsigned char tag,
275 const void *value, size_t vlen)
276{
277 struct x509_parse_context *ctx = context;
278
279 switch (ctx->last_oid) {
280 case OID_commonName:
281 ctx->cn_size = vlen;
282 ctx->cn_offset = (unsigned long)value - ctx->data;
283 break;
284 case OID_organizationName:
285 ctx->o_size = vlen;
286 ctx->o_offset = (unsigned long)value - ctx->data;
287 break;
288 case OID_email_address:
289 ctx->email_size = vlen;
290 ctx->email_offset = (unsigned long)value - ctx->data;
291 break;
292 default:
293 break;
294 }
295
296 return 0;
297}
298
299/*
300 * Fabricate and save the issuer and subject names
301 */
302static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen,
303 unsigned char tag,
304 char **_name, size_t vlen)
305{
306 const void *name, *data = (const void *)ctx->data;
307 size_t namesize;
308 char *buffer;
309
310 if (*_name)
311 return -EINVAL;
312
313 /* Empty name string if no material */
314 if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) {
315 buffer = kmalloc(1, GFP_KERNEL);
316 if (!buffer)
317 return -ENOMEM;
318 buffer[0] = 0;
319 goto done;
320 }
321
322 if (ctx->cn_size && ctx->o_size) {
323 /* Consider combining O and CN, but use only the CN if it is
324 * prefixed by the O, or a significant portion thereof.
325 */
326 namesize = ctx->cn_size;
327 name = data + ctx->cn_offset;
328 if (ctx->cn_size >= ctx->o_size &&
329 memcmp(data + ctx->cn_offset, data + ctx->o_offset,
330 ctx->o_size) == 0)
331 goto single_component;
332 if (ctx->cn_size >= 7 &&
333 ctx->o_size >= 7 &&
334 memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0)
335 goto single_component;
336
337 buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1,
338 GFP_KERNEL);
339 if (!buffer)
340 return -ENOMEM;
341
342 memcpy(buffer,
343 data + ctx->o_offset, ctx->o_size);
344 buffer[ctx->o_size + 0] = ':';
345 buffer[ctx->o_size + 1] = ' ';
346 memcpy(buffer + ctx->o_size + 2,
347 data + ctx->cn_offset, ctx->cn_size);
348 buffer[ctx->o_size + 2 + ctx->cn_size] = 0;
349 goto done;
350
351 } else if (ctx->cn_size) {
352 namesize = ctx->cn_size;
353 name = data + ctx->cn_offset;
354 } else if (ctx->o_size) {
355 namesize = ctx->o_size;
356 name = data + ctx->o_offset;
357 } else {
358 namesize = ctx->email_size;
359 name = data + ctx->email_offset;
360 }
361
362single_component:
363 buffer = kmalloc(namesize + 1, GFP_KERNEL);
364 if (!buffer)
365 return -ENOMEM;
366 memcpy(buffer, name, namesize);
367 buffer[namesize] = 0;
368
369done:
370 *_name = buffer;
371 ctx->cn_size = 0;
372 ctx->o_size = 0;
373 ctx->email_size = 0;
374 return 0;
375}
376
377int x509_note_issuer(void *context, size_t hdrlen,
378 unsigned char tag,
379 const void *value, size_t vlen)
380{
381 struct x509_parse_context *ctx = context;
382 ctx->cert->raw_issuer = value;
383 ctx->cert->raw_issuer_size = vlen;
384 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen);
385}
386
387int x509_note_subject(void *context, size_t hdrlen,
388 unsigned char tag,
389 const void *value, size_t vlen)
390{
391 struct x509_parse_context *ctx = context;
392 ctx->cert->raw_subject = value;
393 ctx->cert->raw_subject_size = vlen;
394 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen);
395}
396
397/*
398 * Extract the data for the public key algorithm
399 */
400int x509_extract_key_data(void *context, size_t hdrlen,
401 unsigned char tag,
402 const void *value, size_t vlen)
403{
404 struct x509_parse_context *ctx = context;
405
406 if (ctx->last_oid != OID_rsaEncryption)
407 return -ENOPKG;
408
409 ctx->cert->pub->pkey_algo = "rsa";
410
411 /* Discard the BIT STRING metadata */
412 if (vlen < 1 || *(const u8 *)value != 0)
413 return -EBADMSG;
414 ctx->key = value + 1;
415 ctx->key_size = vlen - 1;
416 return 0;
417}
418
419/* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */
420#define SEQ_TAG_KEYID (ASN1_CONT << 6)
421
422/*
423 * Process certificate extensions that are used to qualify the certificate.
424 */
425int x509_process_extension(void *context, size_t hdrlen,
426 unsigned char tag,
427 const void *value, size_t vlen)
428{
429 struct x509_parse_context *ctx = context;
430 struct asymmetric_key_id *kid;
431 const unsigned char *v = value;
432
433 pr_debug("Extension: %u\n", ctx->last_oid);
434
435 if (ctx->last_oid == OID_subjectKeyIdentifier) {
436 /* Get hold of the key fingerprint */
437 if (ctx->cert->skid || vlen < 3)
438 return -EBADMSG;
439 if (v[0] != ASN1_OTS || v[1] != vlen - 2)
440 return -EBADMSG;
441 v += 2;
442 vlen -= 2;
443
444 ctx->cert->raw_skid_size = vlen;
445 ctx->cert->raw_skid = v;
446 kid = asymmetric_key_generate_id(v, vlen, "", 0);
447 if (IS_ERR(kid))
448 return PTR_ERR(kid);
449 ctx->cert->skid = kid;
450 pr_debug("subjkeyid %*phN\n", kid->len, kid->data);
451 return 0;
452 }
453
454 if (ctx->last_oid == OID_authorityKeyIdentifier) {
455 /* Get hold of the CA key fingerprint */
456 ctx->raw_akid = v;
457 ctx->raw_akid_size = vlen;
458 return 0;
459 }
460
461 return 0;
462}
463
464/**
465 * x509_decode_time - Decode an X.509 time ASN.1 object
466 * @_t: The time to fill in
467 * @hdrlen: The length of the object header
468 * @tag: The object tag
469 * @value: The object value
470 * @vlen: The size of the object value
471 *
472 * Decode an ASN.1 universal time or generalised time field into a struct the
473 * kernel can handle and check it for validity. The time is decoded thus:
474 *
475 * [RFC5280 ยง4.1.2.5]
476 * CAs conforming to this profile MUST always encode certificate validity
477 * dates through the year 2049 as UTCTime; certificate validity dates in
478 * 2050 or later MUST be encoded as GeneralizedTime. Conforming
479 * applications MUST be able to process validity dates that are encoded in
480 * either UTCTime or GeneralizedTime.
481 */
482int x509_decode_time(time64_t *_t, size_t hdrlen,
483 unsigned char tag,
484 const unsigned char *value, size_t vlen)
485{
486 static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30,
487 31, 31, 30, 31, 30, 31 };
488 const unsigned char *p = value;
489 unsigned year, mon, day, hour, min, sec, mon_len;
490
491#define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; })
492#define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
493
494 if (tag == ASN1_UNITIM) {
495 /* UTCTime: YYMMDDHHMMSSZ */
496 if (vlen != 13)
497 goto unsupported_time;
498 year = DD2bin(p);
499 if (year >= 50)
500 year += 1900;
501 else
502 year += 2000;
503 } else if (tag == ASN1_GENTIM) {
504 /* GenTime: YYYYMMDDHHMMSSZ */
505 if (vlen != 15)
506 goto unsupported_time;
507 year = DD2bin(p) * 100 + DD2bin(p);
508 if (year >= 1950 && year <= 2049)
509 goto invalid_time;
510 } else {
511 goto unsupported_time;
512 }
513
514 mon = DD2bin(p);
515 day = DD2bin(p);
516 hour = DD2bin(p);
517 min = DD2bin(p);
518 sec = DD2bin(p);
519
520 if (*p != 'Z')
521 goto unsupported_time;
522
523 if (year < 1970 ||
524 mon < 1 || mon > 12)
525 goto invalid_time;
526
527 mon_len = month_lengths[mon - 1];
528 if (mon == 2) {
529 if (year % 4 == 0) {
530 mon_len = 29;
531 if (year % 100 == 0) {
532 mon_len = 28;
533 if (year % 400 == 0)
534 mon_len = 29;
535 }
536 }
537 }
538
539 if (day < 1 || day > mon_len ||
540 hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
541 min > 59 ||
542 sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
543 goto invalid_time;
544
545 *_t = mktime64(year, mon, day, hour, min, sec);
546 return 0;
547
548unsupported_time:
549 pr_debug("Got unsupported time [tag %02x]: '%*phN'\n",
550 tag, (int)vlen, value);
551 return -EBADMSG;
552invalid_time:
553 pr_debug("Got invalid time [tag %02x]: '%*phN'\n",
554 tag, (int)vlen, value);
555 return -EBADMSG;
556}
557EXPORT_SYMBOL_GPL(x509_decode_time);
558
559int x509_note_not_before(void *context, size_t hdrlen,
560 unsigned char tag,
561 const void *value, size_t vlen)
562{
563 struct x509_parse_context *ctx = context;
564 return x509_decode_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
565}
566
567int x509_note_not_after(void *context, size_t hdrlen,
568 unsigned char tag,
569 const void *value, size_t vlen)
570{
571 struct x509_parse_context *ctx = context;
572 return x509_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
573}
574
575/*
576 * Note a key identifier-based AuthorityKeyIdentifier
577 */
578int x509_akid_note_kid(void *context, size_t hdrlen,
579 unsigned char tag,
580 const void *value, size_t vlen)
581{
582 struct x509_parse_context *ctx = context;
583 struct asymmetric_key_id *kid;
584
585 pr_debug("AKID: keyid: %*phN\n", (int)vlen, value);
586
587 if (ctx->cert->sig->auth_ids[1])
588 return 0;
589
590 kid = asymmetric_key_generate_id(value, vlen, "", 0);
591 if (IS_ERR(kid))
592 return PTR_ERR(kid);
593 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
594 ctx->cert->sig->auth_ids[1] = kid;
595 return 0;
596}
597
598/*
599 * Note a directoryName in an AuthorityKeyIdentifier
600 */
601int x509_akid_note_name(void *context, size_t hdrlen,
602 unsigned char tag,
603 const void *value, size_t vlen)
604{
605 struct x509_parse_context *ctx = context;
606
607 pr_debug("AKID: name: %*phN\n", (int)vlen, value);
608
609 ctx->akid_raw_issuer = value;
610 ctx->akid_raw_issuer_size = vlen;
611 return 0;
612}
613
614/*
615 * Note a serial number in an AuthorityKeyIdentifier
616 */
617int x509_akid_note_serial(void *context, size_t hdrlen,
618 unsigned char tag,
619 const void *value, size_t vlen)
620{
621 struct x509_parse_context *ctx = context;
622 struct asymmetric_key_id *kid;
623
624 pr_debug("AKID: serial: %*phN\n", (int)vlen, value);
625
626 if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0])
627 return 0;
628
629 kid = asymmetric_key_generate_id(value,
630 vlen,
631 ctx->akid_raw_issuer,
632 ctx->akid_raw_issuer_size);
633 if (IS_ERR(kid))
634 return PTR_ERR(kid);
635
636 pr_debug("authkeyid %*phN\n", kid->len, kid->data);
637 ctx->cert->sig->auth_ids[0] = kid;
638 return 0;
639}