Loading...
Note: File does not exist in v3.5.6.
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(sinfo->sig);
49 kfree(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(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(-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(&pkcs7_decoder, ctx, data, datalen);
141 if (ret < 0) {
142 msg = ERR_PTR(ret);
143 goto out;
144 }
145
146 ret = pkcs7_check_authattrs(ctx->msg);
147 if (ret < 0) {
148 msg = ERR_PTR(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(ctx->sinfo);
163out_no_sinfo:
164 pkcs7_free_message(ctx->msg);
165out_no_msg:
166 kfree(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(value, 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_md4:
231 ctx->sinfo->sig->hash_algo = "md4";
232 break;
233 case OID_md5:
234 ctx->sinfo->sig->hash_algo = "md5";
235 break;
236 case OID_sha1:
237 ctx->sinfo->sig->hash_algo = "sha1";
238 break;
239 case OID_sha256:
240 ctx->sinfo->sig->hash_algo = "sha256";
241 break;
242 case OID_sha384:
243 ctx->sinfo->sig->hash_algo = "sha384";
244 break;
245 case OID_sha512:
246 ctx->sinfo->sig->hash_algo = "sha512";
247 break;
248 case OID_sha224:
249 ctx->sinfo->sig->hash_algo = "sha224";
250 break;
251 default:
252 printk("Unsupported digest algo: %u\n", ctx->last_oid);
253 return -ENOPKG;
254 }
255 return 0;
256}
257
258/*
259 * Note the public key algorithm for the signature.
260 */
261int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen,
262 unsigned char tag,
263 const void *value, size_t vlen)
264{
265 struct pkcs7_parse_context *ctx = context;
266
267 switch (ctx->last_oid) {
268 case OID_rsaEncryption:
269 ctx->sinfo->sig->pkey_algo = "rsa";
270 ctx->sinfo->sig->encoding = "pkcs1";
271 break;
272 default:
273 printk("Unsupported pkey algo: %u\n", ctx->last_oid);
274 return -ENOPKG;
275 }
276 return 0;
277}
278
279/*
280 * We only support signed data [RFC2315 sec 9].
281 */
282int pkcs7_check_content_type(void *context, size_t hdrlen,
283 unsigned char tag,
284 const void *value, size_t vlen)
285{
286 struct pkcs7_parse_context *ctx = context;
287
288 if (ctx->last_oid != OID_signed_data) {
289 pr_warn("Only support pkcs7_signedData type\n");
290 return -EINVAL;
291 }
292
293 return 0;
294}
295
296/*
297 * Note the SignedData version
298 */
299int pkcs7_note_signeddata_version(void *context, size_t hdrlen,
300 unsigned char tag,
301 const void *value, size_t vlen)
302{
303 struct pkcs7_parse_context *ctx = context;
304 unsigned version;
305
306 if (vlen != 1)
307 goto unsupported;
308
309 ctx->msg->version = version = *(const u8 *)value;
310 switch (version) {
311 case 1:
312 /* PKCS#7 SignedData [RFC2315 sec 9.1]
313 * CMS ver 1 SignedData [RFC5652 sec 5.1]
314 */
315 break;
316 case 3:
317 /* CMS ver 3 SignedData [RFC2315 sec 5.1] */
318 break;
319 default:
320 goto unsupported;
321 }
322
323 return 0;
324
325unsupported:
326 pr_warn("Unsupported SignedData version\n");
327 return -EINVAL;
328}
329
330/*
331 * Note the SignerInfo version
332 */
333int pkcs7_note_signerinfo_version(void *context, size_t hdrlen,
334 unsigned char tag,
335 const void *value, size_t vlen)
336{
337 struct pkcs7_parse_context *ctx = context;
338 unsigned version;
339
340 if (vlen != 1)
341 goto unsupported;
342
343 version = *(const u8 *)value;
344 switch (version) {
345 case 1:
346 /* PKCS#7 SignerInfo [RFC2315 sec 9.2]
347 * CMS ver 1 SignerInfo [RFC5652 sec 5.3]
348 */
349 if (ctx->msg->version != 1)
350 goto version_mismatch;
351 ctx->expect_skid = false;
352 break;
353 case 3:
354 /* CMS ver 3 SignerInfo [RFC2315 sec 5.3] */
355 if (ctx->msg->version == 1)
356 goto version_mismatch;
357 ctx->expect_skid = true;
358 break;
359 default:
360 goto unsupported;
361 }
362
363 return 0;
364
365unsupported:
366 pr_warn("Unsupported SignerInfo version\n");
367 return -EINVAL;
368version_mismatch:
369 pr_warn("SignedData-SignerInfo version mismatch\n");
370 return -EBADMSG;
371}
372
373/*
374 * Extract a certificate and store it in the context.
375 */
376int pkcs7_extract_cert(void *context, size_t hdrlen,
377 unsigned char tag,
378 const void *value, size_t vlen)
379{
380 struct pkcs7_parse_context *ctx = context;
381 struct x509_certificate *x509;
382
383 if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) {
384 pr_debug("Cert began with tag %02x at %lu\n",
385 tag, (unsigned long)ctx - ctx->data);
386 return -EBADMSG;
387 }
388
389 /* We have to correct for the header so that the X.509 parser can start
390 * from the beginning. Note that since X.509 stipulates DER, there
391 * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which
392 * stipulates BER).
393 */
394 value -= hdrlen;
395 vlen += hdrlen;
396
397 if (((u8*)value)[1] == 0x80)
398 vlen += 2; /* Indefinite length - there should be an EOC */
399
400 x509 = x509_cert_parse(value, vlen);
401 if (IS_ERR(x509))
402 return PTR_ERR(x509);
403
404 x509->index = ++ctx->x509_index;
405 pr_debug("Got cert %u for %s\n", x509->index, x509->subject);
406 pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data);
407
408 *ctx->ppcerts = x509;
409 ctx->ppcerts = &x509->next;
410 return 0;
411}
412
413/*
414 * Save the certificate list
415 */
416int pkcs7_note_certificate_list(void *context, size_t hdrlen,
417 unsigned char tag,
418 const void *value, size_t vlen)
419{
420 struct pkcs7_parse_context *ctx = context;
421
422 pr_devel("Got cert list (%02x)\n", tag);
423
424 *ctx->ppcerts = ctx->msg->certs;
425 ctx->msg->certs = ctx->certs;
426 ctx->certs = NULL;
427 ctx->ppcerts = &ctx->certs;
428 return 0;
429}
430
431/*
432 * Note the content type.
433 */
434int pkcs7_note_content(void *context, size_t hdrlen,
435 unsigned char tag,
436 const void *value, size_t vlen)
437{
438 struct pkcs7_parse_context *ctx = context;
439
440 if (ctx->last_oid != OID_data &&
441 ctx->last_oid != OID_msIndirectData) {
442 pr_warn("Unsupported data type %d\n", ctx->last_oid);
443 return -EINVAL;
444 }
445
446 ctx->msg->data_type = ctx->last_oid;
447 return 0;
448}
449
450/*
451 * Extract the data from the message and store that and its content type OID in
452 * the context.
453 */
454int pkcs7_note_data(void *context, size_t hdrlen,
455 unsigned char tag,
456 const void *value, size_t vlen)
457{
458 struct pkcs7_parse_context *ctx = context;
459
460 pr_debug("Got data\n");
461
462 ctx->msg->data = value;
463 ctx->msg->data_len = vlen;
464 ctx->msg->data_hdrlen = hdrlen;
465 return 0;
466}
467
468/*
469 * Parse authenticated attributes.
470 */
471int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen,
472 unsigned char tag,
473 const void *value, size_t vlen)
474{
475 struct pkcs7_parse_context *ctx = context;
476 struct pkcs7_signed_info *sinfo = ctx->sinfo;
477 enum OID content_type;
478
479 pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
480
481 switch (ctx->last_oid) {
482 case OID_contentType:
483 if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set))
484 goto repeated;
485 content_type = look_up_OID(value, vlen);
486 if (content_type != ctx->msg->data_type) {
487 pr_warn("Mismatch between global data type (%d) and sinfo %u (%d)\n",
488 ctx->msg->data_type, sinfo->index,
489 content_type);
490 return -EBADMSG;
491 }
492 return 0;
493
494 case OID_signingTime:
495 if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set))
496 goto repeated;
497 /* Should we check that the signing time is consistent
498 * with the signer's X.509 cert?
499 */
500 return x509_decode_time(&sinfo->signing_time,
501 hdrlen, tag, value, vlen);
502
503 case OID_messageDigest:
504 if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set))
505 goto repeated;
506 if (tag != ASN1_OTS)
507 return -EBADMSG;
508 sinfo->msgdigest = value;
509 sinfo->msgdigest_len = vlen;
510 return 0;
511
512 case OID_smimeCapabilites:
513 if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set))
514 goto repeated;
515 if (ctx->msg->data_type != OID_msIndirectData) {
516 pr_warn("S/MIME Caps only allowed with Authenticode\n");
517 return -EKEYREJECTED;
518 }
519 return 0;
520
521 /* Microsoft SpOpusInfo seems to be contain cont[0] 16-bit BE
522 * char URLs and cont[1] 8-bit char URLs.
523 *
524 * Microsoft StatementType seems to contain a list of OIDs that
525 * are also used as extendedKeyUsage types in X.509 certs.
526 */
527 case OID_msSpOpusInfo:
528 if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set))
529 goto repeated;
530 goto authenticode_check;
531 case OID_msStatementType:
532 if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set))
533 goto repeated;
534 authenticode_check:
535 if (ctx->msg->data_type != OID_msIndirectData) {
536 pr_warn("Authenticode AuthAttrs only allowed with Authenticode\n");
537 return -EKEYREJECTED;
538 }
539 /* I'm not sure how to validate these */
540 return 0;
541 default:
542 return 0;
543 }
544
545repeated:
546 /* We permit max one item per AuthenticatedAttribute and no repeats */
547 pr_warn("Repeated/multivalue AuthAttrs not permitted\n");
548 return -EKEYREJECTED;
549}
550
551/*
552 * Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3]
553 */
554int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen,
555 unsigned char tag,
556 const void *value, size_t vlen)
557{
558 struct pkcs7_parse_context *ctx = context;
559 struct pkcs7_signed_info *sinfo = ctx->sinfo;
560
561 if (!test_bit(sinfo_has_content_type, &sinfo->aa_set) ||
562 !test_bit(sinfo_has_message_digest, &sinfo->aa_set)) {
563 pr_warn("Missing required AuthAttr\n");
564 return -EBADMSG;
565 }
566
567 if (ctx->msg->data_type != OID_msIndirectData &&
568 test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) {
569 pr_warn("Unexpected Authenticode AuthAttr\n");
570 return -EBADMSG;
571 }
572
573 /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */
574 sinfo->authattrs = value - (hdrlen - 1);
575 sinfo->authattrs_len = vlen + (hdrlen - 1);
576 return 0;
577}
578
579/*
580 * Note the issuing certificate serial number
581 */
582int pkcs7_sig_note_serial(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 ctx->raw_serial = value;
588 ctx->raw_serial_size = vlen;
589 return 0;
590}
591
592/*
593 * Note the issuer's name
594 */
595int pkcs7_sig_note_issuer(void *context, size_t hdrlen,
596 unsigned char tag,
597 const void *value, size_t vlen)
598{
599 struct pkcs7_parse_context *ctx = context;
600 ctx->raw_issuer = value;
601 ctx->raw_issuer_size = vlen;
602 return 0;
603}
604
605/*
606 * Note the issuing cert's subjectKeyIdentifier
607 */
608int pkcs7_sig_note_skid(void *context, size_t hdrlen,
609 unsigned char tag,
610 const void *value, size_t vlen)
611{
612 struct pkcs7_parse_context *ctx = context;
613
614 pr_devel("SKID: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
615
616 ctx->raw_skid = value;
617 ctx->raw_skid_size = vlen;
618 return 0;
619}
620
621/*
622 * Note the signature data
623 */
624int pkcs7_sig_note_signature(void *context, size_t hdrlen,
625 unsigned char tag,
626 const void *value, size_t vlen)
627{
628 struct pkcs7_parse_context *ctx = context;
629
630 ctx->sinfo->sig->s = kmemdup(value, vlen, GFP_KERNEL);
631 if (!ctx->sinfo->sig->s)
632 return -ENOMEM;
633
634 ctx->sinfo->sig->s_size = vlen;
635 return 0;
636}
637
638/*
639 * Note a signature information block
640 */
641int pkcs7_note_signed_info(void *context, size_t hdrlen,
642 unsigned char tag,
643 const void *value, size_t vlen)
644{
645 struct pkcs7_parse_context *ctx = context;
646 struct pkcs7_signed_info *sinfo = ctx->sinfo;
647 struct asymmetric_key_id *kid;
648
649 if (ctx->msg->data_type == OID_msIndirectData && !sinfo->authattrs) {
650 pr_warn("Authenticode requires AuthAttrs\n");
651 return -EBADMSG;
652 }
653
654 /* Generate cert issuer + serial number key ID */
655 if (!ctx->expect_skid) {
656 kid = asymmetric_key_generate_id(ctx->raw_serial,
657 ctx->raw_serial_size,
658 ctx->raw_issuer,
659 ctx->raw_issuer_size);
660 } else {
661 kid = asymmetric_key_generate_id(ctx->raw_skid,
662 ctx->raw_skid_size,
663 "", 0);
664 }
665 if (IS_ERR(kid))
666 return PTR_ERR(kid);
667
668 pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data);
669
670 sinfo->sig->auth_ids[0] = kid;
671 sinfo->index = ++ctx->sinfo_index;
672 *ctx->ppsinfo = sinfo;
673 ctx->ppsinfo = &sinfo->next;
674 ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
675 if (!ctx->sinfo)
676 return -ENOMEM;
677 ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature),
678 GFP_KERNEL);
679 if (!ctx->sinfo->sig)
680 return -ENOMEM;
681 return 0;
682}