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(size: sizeof(struct pkcs7_parse_context), GFP_KERNEL);
122 if (!ctx)
123 goto out_no_ctx;
124 ctx->msg = kzalloc(size: sizeof(struct pkcs7_message), GFP_KERNEL);
125 if (!ctx->msg)
126 goto out_no_msg;
127 ctx->sinfo = kzalloc(size: sizeof(struct pkcs7_signed_info), GFP_KERNEL);
128 if (!ctx->sinfo)
129 goto out_no_sinfo;
130 ctx->sinfo->sig = kzalloc(size: 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(&pkcs7_decoder, 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_SM2_with_SM3:
296 ctx->sinfo->sig->pkey_algo = "sm2";
297 ctx->sinfo->sig->encoding = "raw";
298 break;
299 case OID_gost2012PKey256:
300 case OID_gost2012PKey512:
301 ctx->sinfo->sig->pkey_algo = "ecrdsa";
302 ctx->sinfo->sig->encoding = "raw";
303 break;
304 default:
305 printk("Unsupported pkey algo: %u\n", ctx->last_oid);
306 return -ENOPKG;
307 }
308 return 0;
309}
310
311/*
312 * We only support signed data [RFC2315 sec 9].
313 */
314int pkcs7_check_content_type(void *context, size_t hdrlen,
315 unsigned char tag,
316 const void *value, size_t vlen)
317{
318 struct pkcs7_parse_context *ctx = context;
319
320 if (ctx->last_oid != OID_signed_data) {
321 pr_warn("Only support pkcs7_signedData type\n");
322 return -EINVAL;
323 }
324
325 return 0;
326}
327
328/*
329 * Note the SignedData version
330 */
331int pkcs7_note_signeddata_version(void *context, size_t hdrlen,
332 unsigned char tag,
333 const void *value, size_t vlen)
334{
335 struct pkcs7_parse_context *ctx = context;
336 unsigned version;
337
338 if (vlen != 1)
339 goto unsupported;
340
341 ctx->msg->version = version = *(const u8 *)value;
342 switch (version) {
343 case 1:
344 /* PKCS#7 SignedData [RFC2315 sec 9.1]
345 * CMS ver 1 SignedData [RFC5652 sec 5.1]
346 */
347 break;
348 case 3:
349 /* CMS ver 3 SignedData [RFC2315 sec 5.1] */
350 break;
351 default:
352 goto unsupported;
353 }
354
355 return 0;
356
357unsupported:
358 pr_warn("Unsupported SignedData version\n");
359 return -EINVAL;
360}
361
362/*
363 * Note the SignerInfo version
364 */
365int pkcs7_note_signerinfo_version(void *context, size_t hdrlen,
366 unsigned char tag,
367 const void *value, size_t vlen)
368{
369 struct pkcs7_parse_context *ctx = context;
370 unsigned version;
371
372 if (vlen != 1)
373 goto unsupported;
374
375 version = *(const u8 *)value;
376 switch (version) {
377 case 1:
378 /* PKCS#7 SignerInfo [RFC2315 sec 9.2]
379 * CMS ver 1 SignerInfo [RFC5652 sec 5.3]
380 */
381 if (ctx->msg->version != 1)
382 goto version_mismatch;
383 ctx->expect_skid = false;
384 break;
385 case 3:
386 /* CMS ver 3 SignerInfo [RFC2315 sec 5.3] */
387 if (ctx->msg->version == 1)
388 goto version_mismatch;
389 ctx->expect_skid = true;
390 break;
391 default:
392 goto unsupported;
393 }
394
395 return 0;
396
397unsupported:
398 pr_warn("Unsupported SignerInfo version\n");
399 return -EINVAL;
400version_mismatch:
401 pr_warn("SignedData-SignerInfo version mismatch\n");
402 return -EBADMSG;
403}
404
405/*
406 * Extract a certificate and store it in the context.
407 */
408int pkcs7_extract_cert(void *context, size_t hdrlen,
409 unsigned char tag,
410 const void *value, size_t vlen)
411{
412 struct pkcs7_parse_context *ctx = context;
413 struct x509_certificate *x509;
414
415 if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) {
416 pr_debug("Cert began with tag %02x at %lu\n",
417 tag, (unsigned long)ctx - ctx->data);
418 return -EBADMSG;
419 }
420
421 /* We have to correct for the header so that the X.509 parser can start
422 * from the beginning. Note that since X.509 stipulates DER, there
423 * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which
424 * stipulates BER).
425 */
426 value -= hdrlen;
427 vlen += hdrlen;
428
429 if (((u8*)value)[1] == 0x80)
430 vlen += 2; /* Indefinite length - there should be an EOC */
431
432 x509 = x509_cert_parse(data: value, datalen: vlen);
433 if (IS_ERR(ptr: x509))
434 return PTR_ERR(ptr: x509);
435
436 x509->index = ++ctx->x509_index;
437 pr_debug("Got cert %u for %s\n", x509->index, x509->subject);
438 pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data);
439
440 *ctx->ppcerts = x509;
441 ctx->ppcerts = &x509->next;
442 return 0;
443}
444
445/*
446 * Save the certificate list
447 */
448int pkcs7_note_certificate_list(void *context, size_t hdrlen,
449 unsigned char tag,
450 const void *value, size_t vlen)
451{
452 struct pkcs7_parse_context *ctx = context;
453
454 pr_devel("Got cert list (%02x)\n", tag);
455
456 *ctx->ppcerts = ctx->msg->certs;
457 ctx->msg->certs = ctx->certs;
458 ctx->certs = NULL;
459 ctx->ppcerts = &ctx->certs;
460 return 0;
461}
462
463/*
464 * Note the content type.
465 */
466int pkcs7_note_content(void *context, size_t hdrlen,
467 unsigned char tag,
468 const void *value, size_t vlen)
469{
470 struct pkcs7_parse_context *ctx = context;
471
472 if (ctx->last_oid != OID_data &&
473 ctx->last_oid != OID_msIndirectData) {
474 pr_warn("Unsupported data type %d\n", ctx->last_oid);
475 return -EINVAL;
476 }
477
478 ctx->msg->data_type = ctx->last_oid;
479 return 0;
480}
481
482/*
483 * Extract the data from the message and store that and its content type OID in
484 * the context.
485 */
486int pkcs7_note_data(void *context, size_t hdrlen,
487 unsigned char tag,
488 const void *value, size_t vlen)
489{
490 struct pkcs7_parse_context *ctx = context;
491
492 pr_debug("Got data\n");
493
494 ctx->msg->data = value;
495 ctx->msg->data_len = vlen;
496 ctx->msg->data_hdrlen = hdrlen;
497 return 0;
498}
499
500/*
501 * Parse authenticated attributes.
502 */
503int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen,
504 unsigned char tag,
505 const void *value, size_t vlen)
506{
507 struct pkcs7_parse_context *ctx = context;
508 struct pkcs7_signed_info *sinfo = ctx->sinfo;
509 enum OID content_type;
510
511 pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
512
513 switch (ctx->last_oid) {
514 case OID_contentType:
515 if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set))
516 goto repeated;
517 content_type = look_up_OID(data: value, datasize: vlen);
518 if (content_type != ctx->msg->data_type) {
519 pr_warn("Mismatch between global data type (%d) and sinfo %u (%d)\n",
520 ctx->msg->data_type, sinfo->index,
521 content_type);
522 return -EBADMSG;
523 }
524 return 0;
525
526 case OID_signingTime:
527 if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set))
528 goto repeated;
529 /* Should we check that the signing time is consistent
530 * with the signer's X.509 cert?
531 */
532 return x509_decode_time(t: &sinfo->signing_time,
533 hdrlen, tag, value, vlen);
534
535 case OID_messageDigest:
536 if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set))
537 goto repeated;
538 if (tag != ASN1_OTS)
539 return -EBADMSG;
540 sinfo->msgdigest = value;
541 sinfo->msgdigest_len = vlen;
542 return 0;
543
544 case OID_smimeCapabilites:
545 if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set))
546 goto repeated;
547 if (ctx->msg->data_type != OID_msIndirectData) {
548 pr_warn("S/MIME Caps only allowed with Authenticode\n");
549 return -EKEYREJECTED;
550 }
551 return 0;
552
553 /* Microsoft SpOpusInfo seems to be contain cont[0] 16-bit BE
554 * char URLs and cont[1] 8-bit char URLs.
555 *
556 * Microsoft StatementType seems to contain a list of OIDs that
557 * are also used as extendedKeyUsage types in X.509 certs.
558 */
559 case OID_msSpOpusInfo:
560 if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set))
561 goto repeated;
562 goto authenticode_check;
563 case OID_msStatementType:
564 if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set))
565 goto repeated;
566 authenticode_check:
567 if (ctx->msg->data_type != OID_msIndirectData) {
568 pr_warn("Authenticode AuthAttrs only allowed with Authenticode\n");
569 return -EKEYREJECTED;
570 }
571 /* I'm not sure how to validate these */
572 return 0;
573 default:
574 return 0;
575 }
576
577repeated:
578 /* We permit max one item per AuthenticatedAttribute and no repeats */
579 pr_warn("Repeated/multivalue AuthAttrs not permitted\n");
580 return -EKEYREJECTED;
581}
582
583/*
584 * Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3]
585 */
586int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen,
587 unsigned char tag,
588 const void *value, size_t vlen)
589{
590 struct pkcs7_parse_context *ctx = context;
591 struct pkcs7_signed_info *sinfo = ctx->sinfo;
592
593 if (!test_bit(sinfo_has_content_type, &sinfo->aa_set) ||
594 !test_bit(sinfo_has_message_digest, &sinfo->aa_set)) {
595 pr_warn("Missing required AuthAttr\n");
596 return -EBADMSG;
597 }
598
599 if (ctx->msg->data_type != OID_msIndirectData &&
600 test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) {
601 pr_warn("Unexpected Authenticode AuthAttr\n");
602 return -EBADMSG;
603 }
604
605 /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */
606 sinfo->authattrs = value - (hdrlen - 1);
607 sinfo->authattrs_len = vlen + (hdrlen - 1);
608 return 0;
609}
610
611/*
612 * Note the issuing certificate serial number
613 */
614int pkcs7_sig_note_serial(void *context, size_t hdrlen,
615 unsigned char tag,
616 const void *value, size_t vlen)
617{
618 struct pkcs7_parse_context *ctx = context;
619 ctx->raw_serial = value;
620 ctx->raw_serial_size = vlen;
621 return 0;
622}
623
624/*
625 * Note the issuer's name
626 */
627int pkcs7_sig_note_issuer(void *context, size_t hdrlen,
628 unsigned char tag,
629 const void *value, size_t vlen)
630{
631 struct pkcs7_parse_context *ctx = context;
632 ctx->raw_issuer = value;
633 ctx->raw_issuer_size = vlen;
634 return 0;
635}
636
637/*
638 * Note the issuing cert's subjectKeyIdentifier
639 */
640int pkcs7_sig_note_skid(void *context, size_t hdrlen,
641 unsigned char tag,
642 const void *value, size_t vlen)
643{
644 struct pkcs7_parse_context *ctx = context;
645
646 pr_devel("SKID: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
647
648 ctx->raw_skid = value;
649 ctx->raw_skid_size = vlen;
650 return 0;
651}
652
653/*
654 * Note the signature data
655 */
656int pkcs7_sig_note_signature(void *context, size_t hdrlen,
657 unsigned char tag,
658 const void *value, size_t vlen)
659{
660 struct pkcs7_parse_context *ctx = context;
661
662 ctx->sinfo->sig->s = kmemdup(p: value, size: vlen, GFP_KERNEL);
663 if (!ctx->sinfo->sig->s)
664 return -ENOMEM;
665
666 ctx->sinfo->sig->s_size = vlen;
667 return 0;
668}
669
670/*
671 * Note a signature information block
672 */
673int pkcs7_note_signed_info(void *context, size_t hdrlen,
674 unsigned char tag,
675 const void *value, size_t vlen)
676{
677 struct pkcs7_parse_context *ctx = context;
678 struct pkcs7_signed_info *sinfo = ctx->sinfo;
679 struct asymmetric_key_id *kid;
680
681 if (ctx->msg->data_type == OID_msIndirectData && !sinfo->authattrs) {
682 pr_warn("Authenticode requires AuthAttrs\n");
683 return -EBADMSG;
684 }
685
686 /* Generate cert issuer + serial number key ID */
687 if (!ctx->expect_skid) {
688 kid = asymmetric_key_generate_id(val_1: ctx->raw_serial,
689 len_1: ctx->raw_serial_size,
690 val_2: ctx->raw_issuer,
691 len_2: ctx->raw_issuer_size);
692 } else {
693 kid = asymmetric_key_generate_id(val_1: ctx->raw_skid,
694 len_1: ctx->raw_skid_size,
695 val_2: "", len_2: 0);
696 }
697 if (IS_ERR(ptr: kid))
698 return PTR_ERR(ptr: kid);
699
700 pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data);
701
702 sinfo->sig->auth_ids[0] = kid;
703 sinfo->index = ++ctx->sinfo_index;
704 *ctx->ppsinfo = sinfo;
705 ctx->ppsinfo = &sinfo->next;
706 ctx->sinfo = kzalloc(size: sizeof(struct pkcs7_signed_info), GFP_KERNEL);
707 if (!ctx->sinfo)
708 return -ENOMEM;
709 ctx->sinfo->sig = kzalloc(size: sizeof(struct public_key_signature),
710 GFP_KERNEL);
711 if (!ctx->sinfo->sig)
712 return -ENOMEM;
713 return 0;
714}
715

source code of linux/crypto/asymmetric_keys/pkcs7_parser.c