1// SPDX-License-Identifier: GPL-2.0-or-later
2/* PKCS#7 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) "PKCS7: "fmt
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/export.h>
12#include <linux/slab.h>
13#include <linux/err.h>
14#include <linux/oid_registry.h>
15#include <crypto/public_key.h>
16#include "pkcs7_parser.h"
17#include "pkcs7.asn1.h"
18
19MODULE_DESCRIPTION("PKCS#7 parser");
20MODULE_AUTHOR("Red Hat, Inc.");
21MODULE_LICENSE("GPL");
22
23struct pkcs7_parse_context {
24 struct pkcs7_message *msg; /* Message being constructed */
25 struct pkcs7_signed_info *sinfo; /* SignedInfo being constructed */
26 struct pkcs7_signed_info **ppsinfo;
27 struct x509_certificate *certs; /* Certificate cache */
28 struct x509_certificate **ppcerts;
29 unsigned long data; /* Start of data */
30 enum OID last_oid; /* Last OID encountered */
31 unsigned x509_index;
32 unsigned sinfo_index;
33 const void *raw_serial;
34 unsigned raw_serial_size;
35 unsigned raw_issuer_size;
36 const void *raw_issuer;
37 const void *raw_skid;
38 unsigned raw_skid_size;
39 bool expect_skid;
40};
41
42/*
43 * Free a signed information block.
44 */
45static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo)
46{
47 if (sinfo) {
48 public_key_signature_free(sig: sinfo->sig);
49 kfree(objp: sinfo);
50 }
51}
52
53/**
54 * pkcs7_free_message - Free a PKCS#7 message
55 * @pkcs7: The PKCS#7 message to free
56 */
57void pkcs7_free_message(struct pkcs7_message *pkcs7)
58{
59 struct x509_certificate *cert;
60 struct pkcs7_signed_info *sinfo;
61
62 if (pkcs7) {
63 while (pkcs7->certs) {
64 cert = pkcs7->certs;
65 pkcs7->certs = cert->next;
66 x509_free_certificate(cert);
67 }
68 while (pkcs7->crl) {
69 cert = pkcs7->crl;
70 pkcs7->crl = cert->next;
71 x509_free_certificate(cert);
72 }
73 while (pkcs7->signed_infos) {
74 sinfo = pkcs7->signed_infos;
75 pkcs7->signed_infos = sinfo->next;
76 pkcs7_free_signed_info(sinfo);
77 }
78 kfree(objp: pkcs7);
79 }
80}
81EXPORT_SYMBOL_GPL(pkcs7_free_message);
82
83/*
84 * Check authenticatedAttributes are provided or not provided consistently.
85 */
86static int pkcs7_check_authattrs(struct pkcs7_message *msg)
87{
88 struct pkcs7_signed_info *sinfo;
89 bool want = false;
90
91 sinfo = msg->signed_infos;
92 if (!sinfo)
93 goto inconsistent;
94
95 if (sinfo->authattrs) {
96 want = true;
97 msg->have_authattrs = true;
98 }
99
100 for (sinfo = sinfo->next; sinfo; sinfo = sinfo->next)
101 if (!!sinfo->authattrs != want)
102 goto inconsistent;
103 return 0;
104
105inconsistent:
106 pr_warn("Inconsistently supplied authAttrs\n");
107 return -EINVAL;
108}
109
110/**
111 * pkcs7_parse_message - Parse a PKCS#7 message
112 * @data: The raw binary ASN.1 encoded message to be parsed
113 * @datalen: The size of the encoded message
114 */
115struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen)
116{
117 struct pkcs7_parse_context *ctx;
118 struct pkcs7_message *msg = ERR_PTR(error: -ENOMEM);
119 int ret;
120
121 ctx = kzalloc(sizeof(struct pkcs7_parse_context), GFP_KERNEL);
122 if (!ctx)
123 goto out_no_ctx;
124 ctx->msg = kzalloc(sizeof(struct pkcs7_message), GFP_KERNEL);
125 if (!ctx->msg)
126 goto out_no_msg;
127 ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
128 if (!ctx->sinfo)
129 goto out_no_sinfo;
130 ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature),
131 GFP_KERNEL);
132 if (!ctx->sinfo->sig)
133 goto out_no_sig;
134
135 ctx->data = (unsigned long)data;
136 ctx->ppcerts = &ctx->certs;
137 ctx->ppsinfo = &ctx->msg->signed_infos;
138
139 /* Attempt to decode the signature */
140 ret = asn1_ber_decoder(decoder: &pkcs7_decoder, context: ctx, data, datalen);
141 if (ret < 0) {
142 msg = ERR_PTR(error: ret);
143 goto out;
144 }
145
146 ret = pkcs7_check_authattrs(msg: ctx->msg);
147 if (ret < 0) {
148 msg = ERR_PTR(error: ret);
149 goto out;
150 }
151
152 msg = ctx->msg;
153 ctx->msg = NULL;
154
155out:
156 while (ctx->certs) {
157 struct x509_certificate *cert = ctx->certs;
158 ctx->certs = cert->next;
159 x509_free_certificate(cert);
160 }
161out_no_sig:
162 pkcs7_free_signed_info(sinfo: ctx->sinfo);
163out_no_sinfo:
164 pkcs7_free_message(ctx->msg);
165out_no_msg:
166 kfree(objp: ctx);
167out_no_ctx:
168 return msg;
169}
170EXPORT_SYMBOL_GPL(pkcs7_parse_message);
171
172/**
173 * pkcs7_get_content_data - Get access to the PKCS#7 content
174 * @pkcs7: The preparsed PKCS#7 message to access
175 * @_data: Place to return a pointer to the data
176 * @_data_len: Place to return the data length
177 * @_headerlen: Size of ASN.1 header not included in _data
178 *
179 * Get access to the data content of the PKCS#7 message. The size of the
180 * header of the ASN.1 object that contains it is also provided and can be used
181 * to adjust *_data and *_data_len to get the entire object.
182 *
183 * Returns -ENODATA if the data object was missing from the message.
184 */
185int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
186 const void **_data, size_t *_data_len,
187 size_t *_headerlen)
188{
189 if (!pkcs7->data)
190 return -ENODATA;
191
192 *_data = pkcs7->data;
193 *_data_len = pkcs7->data_len;
194 if (_headerlen)
195 *_headerlen = pkcs7->data_hdrlen;
196 return 0;
197}
198EXPORT_SYMBOL_GPL(pkcs7_get_content_data);
199
200/*
201 * Note an OID when we find one for later processing when we know how
202 * to interpret it.
203 */
204int pkcs7_note_OID(void *context, size_t hdrlen,
205 unsigned char tag,
206 const void *value, size_t vlen)
207{
208 struct pkcs7_parse_context *ctx = context;
209
210 ctx->last_oid = look_up_OID(data: value, datasize: vlen);
211 if (ctx->last_oid == OID__NR) {
212 char buffer[50];
213 sprint_oid(value, vlen, buffer, sizeof(buffer));
214 printk("PKCS7: Unknown OID: [%lu] %s\n",
215 (unsigned long)value - ctx->data, buffer);
216 }
217 return 0;
218}
219
220/*
221 * Note the digest algorithm for the signature.
222 */
223int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen,
224 unsigned char tag,
225 const void *value, size_t vlen)
226{
227 struct pkcs7_parse_context *ctx = context;
228
229 switch (ctx->last_oid) {
230 case OID_sha1:
231 ctx->sinfo->sig->hash_algo = "sha1";
232 break;
233 case OID_sha256:
234 ctx->sinfo->sig->hash_algo = "sha256";
235 break;
236 case OID_sha384:
237 ctx->sinfo->sig->hash_algo = "sha384";
238 break;
239 case OID_sha512:
240 ctx->sinfo->sig->hash_algo = "sha512";
241 break;
242 case OID_sha224:
243 ctx->sinfo->sig->hash_algo = "sha224";
244 break;
245 case OID_sm3:
246 ctx->sinfo->sig->hash_algo = "sm3";
247 break;
248 case OID_gost2012Digest256:
249 ctx->sinfo->sig->hash_algo = "streebog256";
250 break;
251 case OID_gost2012Digest512:
252 ctx->sinfo->sig->hash_algo = "streebog512";
253 break;
254 case OID_sha3_256:
255 ctx->sinfo->sig->hash_algo = "sha3-256";
256 break;
257 case OID_sha3_384:
258 ctx->sinfo->sig->hash_algo = "sha3-384";
259 break;
260 case OID_sha3_512:
261 ctx->sinfo->sig->hash_algo = "sha3-512";
262 break;
263 default:
264 printk("Unsupported digest algo: %u\n", ctx->last_oid);
265 return -ENOPKG;
266 }
267 return 0;
268}
269
270/*
271 * Note the public key algorithm for the signature.
272 */
273int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen,
274 unsigned char tag,
275 const void *value, size_t vlen)
276{
277 struct pkcs7_parse_context *ctx = context;
278
279 switch (ctx->last_oid) {
280 case OID_rsaEncryption:
281 ctx->sinfo->sig->pkey_algo = "rsa";
282 ctx->sinfo->sig->encoding = "pkcs1";
283 break;
284 case OID_id_ecdsa_with_sha1:
285 case OID_id_ecdsa_with_sha224:
286 case OID_id_ecdsa_with_sha256:
287 case OID_id_ecdsa_with_sha384:
288 case OID_id_ecdsa_with_sha512:
289 case OID_id_ecdsa_with_sha3_256:
290 case OID_id_ecdsa_with_sha3_384:
291 case OID_id_ecdsa_with_sha3_512:
292 ctx->sinfo->sig->pkey_algo = "ecdsa";
293 ctx->sinfo->sig->encoding = "x962";
294 break;
295 case OID_gost2012PKey256:
296 case OID_gost2012PKey512:
297 ctx->sinfo->sig->pkey_algo = "ecrdsa";
298 ctx->sinfo->sig->encoding = "raw";
299 break;
300 default:
301 printk("Unsupported pkey algo: %u\n", ctx->last_oid);
302 return -ENOPKG;
303 }
304 return 0;
305}
306
307/*
308 * We only support signed data [RFC2315 sec 9].
309 */
310int pkcs7_check_content_type(void *context, size_t hdrlen,
311 unsigned char tag,
312 const void *value, size_t vlen)
313{
314 struct pkcs7_parse_context *ctx = context;
315
316 if (ctx->last_oid != OID_signed_data) {
317 pr_warn("Only support pkcs7_signedData type\n");
318 return -EINVAL;
319 }
320
321 return 0;
322}
323
324/*
325 * Note the SignedData version
326 */
327int pkcs7_note_signeddata_version(void *context, size_t hdrlen,
328 unsigned char tag,
329 const void *value, size_t vlen)
330{
331 struct pkcs7_parse_context *ctx = context;
332 unsigned version;
333
334 if (vlen != 1)
335 goto unsupported;
336
337 ctx->msg->version = version = *(const u8 *)value;
338 switch (version) {
339 case 1:
340 /* PKCS#7 SignedData [RFC2315 sec 9.1]
341 * CMS ver 1 SignedData [RFC5652 sec 5.1]
342 */
343 break;
344 case 3:
345 /* CMS ver 3 SignedData [RFC2315 sec 5.1] */
346 break;
347 default:
348 goto unsupported;
349 }
350
351 return 0;
352
353unsupported:
354 pr_warn("Unsupported SignedData version\n");
355 return -EINVAL;
356}
357
358/*
359 * Note the SignerInfo version
360 */
361int pkcs7_note_signerinfo_version(void *context, size_t hdrlen,
362 unsigned char tag,
363 const void *value, size_t vlen)
364{
365 struct pkcs7_parse_context *ctx = context;
366 unsigned version;
367
368 if (vlen != 1)
369 goto unsupported;
370
371 version = *(const u8 *)value;
372 switch (version) {
373 case 1:
374 /* PKCS#7 SignerInfo [RFC2315 sec 9.2]
375 * CMS ver 1 SignerInfo [RFC5652 sec 5.3]
376 */
377 if (ctx->msg->version != 1)
378 goto version_mismatch;
379 ctx->expect_skid = false;
380 break;
381 case 3:
382 /* CMS ver 3 SignerInfo [RFC2315 sec 5.3] */
383 if (ctx->msg->version == 1)
384 goto version_mismatch;
385 ctx->expect_skid = true;
386 break;
387 default:
388 goto unsupported;
389 }
390
391 return 0;
392
393unsupported:
394 pr_warn("Unsupported SignerInfo version\n");
395 return -EINVAL;
396version_mismatch:
397 pr_warn("SignedData-SignerInfo version mismatch\n");
398 return -EBADMSG;
399}
400
401/*
402 * Extract a certificate and store it in the context.
403 */
404int pkcs7_extract_cert(void *context, size_t hdrlen,
405 unsigned char tag,
406 const void *value, size_t vlen)
407{
408 struct pkcs7_parse_context *ctx = context;
409 struct x509_certificate *x509;
410
411 if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) {
412 pr_debug("Cert began with tag %02x at %lu\n",
413 tag, (unsigned long)ctx - ctx->data);
414 return -EBADMSG;
415 }
416
417 /* We have to correct for the header so that the X.509 parser can start
418 * from the beginning. Note that since X.509 stipulates DER, there
419 * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which
420 * stipulates BER).
421 */
422 value -= hdrlen;
423 vlen += hdrlen;
424
425 if (((u8*)value)[1] == 0x80)
426 vlen += 2; /* Indefinite length - there should be an EOC */
427
428 x509 = x509_cert_parse(data: value, datalen: vlen);
429 if (IS_ERR(ptr: x509))
430 return PTR_ERR(ptr: x509);
431
432 x509->index = ++ctx->x509_index;
433 pr_debug("Got cert %u for %s\n", x509->index, x509->subject);
434 pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data);
435
436 *ctx->ppcerts = x509;
437 ctx->ppcerts = &x509->next;
438 return 0;
439}
440
441/*
442 * Save the certificate list
443 */
444int pkcs7_note_certificate_list(void *context, size_t hdrlen,
445 unsigned char tag,
446 const void *value, size_t vlen)
447{
448 struct pkcs7_parse_context *ctx = context;
449
450 pr_devel("Got cert list (%02x)\n", tag);
451
452 *ctx->ppcerts = ctx->msg->certs;
453 ctx->msg->certs = ctx->certs;
454 ctx->certs = NULL;
455 ctx->ppcerts = &ctx->certs;
456 return 0;
457}
458
459/*
460 * Note the content type.
461 */
462int pkcs7_note_content(void *context, size_t hdrlen,
463 unsigned char tag,
464 const void *value, size_t vlen)
465{
466 struct pkcs7_parse_context *ctx = context;
467
468 if (ctx->last_oid != OID_data &&
469 ctx->last_oid != OID_msIndirectData) {
470 pr_warn("Unsupported data type %d\n", ctx->last_oid);
471 return -EINVAL;
472 }
473
474 ctx->msg->data_type = ctx->last_oid;
475 return 0;
476}
477
478/*
479 * Extract the data from the message and store that and its content type OID in
480 * the context.
481 */
482int pkcs7_note_data(void *context, size_t hdrlen,
483 unsigned char tag,
484 const void *value, size_t vlen)
485{
486 struct pkcs7_parse_context *ctx = context;
487
488 pr_debug("Got data\n");
489
490 ctx->msg->data = value;
491 ctx->msg->data_len = vlen;
492 ctx->msg->data_hdrlen = hdrlen;
493 return 0;
494}
495
496/*
497 * Parse authenticated attributes.
498 */
499int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen,
500 unsigned char tag,
501 const void *value, size_t vlen)
502{
503 struct pkcs7_parse_context *ctx = context;
504 struct pkcs7_signed_info *sinfo = ctx->sinfo;
505 enum OID content_type;
506
507 pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
508
509 switch (ctx->last_oid) {
510 case OID_contentType:
511 if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set))
512 goto repeated;
513 content_type = look_up_OID(data: value, datasize: vlen);
514 if (content_type != ctx->msg->data_type) {
515 pr_warn("Mismatch between global data type (%d) and sinfo %u (%d)\n",
516 ctx->msg->data_type, sinfo->index,
517 content_type);
518 return -EBADMSG;
519 }
520 return 0;
521
522 case OID_signingTime:
523 if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set))
524 goto repeated;
525 /* Should we check that the signing time is consistent
526 * with the signer's X.509 cert?
527 */
528 return x509_decode_time(t: &sinfo->signing_time,
529 hdrlen, tag, value, vlen);
530
531 case OID_messageDigest:
532 if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set))
533 goto repeated;
534 if (tag != ASN1_OTS)
535 return -EBADMSG;
536 sinfo->msgdigest = value;
537 sinfo->msgdigest_len = vlen;
538 return 0;
539
540 case OID_smimeCapabilites:
541 if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set))
542 goto repeated;
543 if (ctx->msg->data_type != OID_msIndirectData) {
544 pr_warn("S/MIME Caps only allowed with Authenticode\n");
545 return -EKEYREJECTED;
546 }
547 return 0;
548
549 /* Microsoft SpOpusInfo seems to be contain cont[0] 16-bit BE
550 * char URLs and cont[1] 8-bit char URLs.
551 *
552 * Microsoft StatementType seems to contain a list of OIDs that
553 * are also used as extendedKeyUsage types in X.509 certs.
554 */
555 case OID_msSpOpusInfo:
556 if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set))
557 goto repeated;
558 goto authenticode_check;
559 case OID_msStatementType:
560 if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set))
561 goto repeated;
562 authenticode_check:
563 if (ctx->msg->data_type != OID_msIndirectData) {
564 pr_warn("Authenticode AuthAttrs only allowed with Authenticode\n");
565 return -EKEYREJECTED;
566 }
567 /* I'm not sure how to validate these */
568 return 0;
569 default:
570 return 0;
571 }
572
573repeated:
574 /* We permit max one item per AuthenticatedAttribute and no repeats */
575 pr_warn("Repeated/multivalue AuthAttrs not permitted\n");
576 return -EKEYREJECTED;
577}
578
579/*
580 * Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3]
581 */
582int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen,
583 unsigned char tag,
584 const void *value, size_t vlen)
585{
586 struct pkcs7_parse_context *ctx = context;
587 struct pkcs7_signed_info *sinfo = ctx->sinfo;
588
589 if (!test_bit(sinfo_has_content_type, &sinfo->aa_set) ||
590 !test_bit(sinfo_has_message_digest, &sinfo->aa_set)) {
591 pr_warn("Missing required AuthAttr\n");
592 return -EBADMSG;
593 }
594
595 if (ctx->msg->data_type != OID_msIndirectData &&
596 test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) {
597 pr_warn("Unexpected Authenticode AuthAttr\n");
598 return -EBADMSG;
599 }
600
601 /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */
602 sinfo->authattrs = value - (hdrlen - 1);
603 sinfo->authattrs_len = vlen + (hdrlen - 1);
604 return 0;
605}
606
607/*
608 * Note the issuing certificate serial number
609 */
610int pkcs7_sig_note_serial(void *context, size_t hdrlen,
611 unsigned char tag,
612 const void *value, size_t vlen)
613{
614 struct pkcs7_parse_context *ctx = context;
615 ctx->raw_serial = value;
616 ctx->raw_serial_size = vlen;
617 return 0;
618}
619
620/*
621 * Note the issuer's name
622 */
623int pkcs7_sig_note_issuer(void *context, size_t hdrlen,
624 unsigned char tag,
625 const void *value, size_t vlen)
626{
627 struct pkcs7_parse_context *ctx = context;
628 ctx->raw_issuer = value;
629 ctx->raw_issuer_size = vlen;
630 return 0;
631}
632
633/*
634 * Note the issuing cert's subjectKeyIdentifier
635 */
636int pkcs7_sig_note_skid(void *context, size_t hdrlen,
637 unsigned char tag,
638 const void *value, size_t vlen)
639{
640 struct pkcs7_parse_context *ctx = context;
641
642 pr_devel("SKID: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
643
644 ctx->raw_skid = value;
645 ctx->raw_skid_size = vlen;
646 return 0;
647}
648
649/*
650 * Note the signature data
651 */
652int pkcs7_sig_note_signature(void *context, size_t hdrlen,
653 unsigned char tag,
654 const void *value, size_t vlen)
655{
656 struct pkcs7_parse_context *ctx = context;
657
658 ctx->sinfo->sig->s = kmemdup(value, vlen, GFP_KERNEL);
659 if (!ctx->sinfo->sig->s)
660 return -ENOMEM;
661
662 ctx->sinfo->sig->s_size = vlen;
663 return 0;
664}
665
666/*
667 * Note a signature information block
668 */
669int pkcs7_note_signed_info(void *context, size_t hdrlen,
670 unsigned char tag,
671 const void *value, size_t vlen)
672{
673 struct pkcs7_parse_context *ctx = context;
674 struct pkcs7_signed_info *sinfo = ctx->sinfo;
675 struct asymmetric_key_id *kid;
676
677 if (ctx->msg->data_type == OID_msIndirectData && !sinfo->authattrs) {
678 pr_warn("Authenticode requires AuthAttrs\n");
679 return -EBADMSG;
680 }
681
682 /* Generate cert issuer + serial number key ID */
683 if (!ctx->expect_skid) {
684 kid = asymmetric_key_generate_id(val_1: ctx->raw_serial,
685 len_1: ctx->raw_serial_size,
686 val_2: ctx->raw_issuer,
687 len_2: ctx->raw_issuer_size);
688 } else {
689 kid = asymmetric_key_generate_id(val_1: ctx->raw_skid,
690 len_1: ctx->raw_skid_size,
691 val_2: "", len_2: 0);
692 }
693 if (IS_ERR(ptr: kid))
694 return PTR_ERR(ptr: kid);
695
696 pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data);
697
698 sinfo->sig->auth_ids[0] = kid;
699 sinfo->index = ++ctx->sinfo_index;
700 *ctx->ppsinfo = sinfo;
701 ctx->ppsinfo = &sinfo->next;
702 ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
703 if (!ctx->sinfo)
704 return -ENOMEM;
705 ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature),
706 GFP_KERNEL);
707 if (!ctx->sinfo->sig)
708 return -ENOMEM;
709 return 0;
710}
711