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 #ifdef __UBOOT__
10 #include <log.h>
11 #include <dm/devres.h>
12 #include <linux/bitops.h>
13 #include <linux/compat.h>
14 #include <linux/printk.h>
15 #endif
16 #include <linux/kernel.h>
17 #ifndef __UBOOT__
18 #include <linux/module.h>
19 #include <linux/export.h>
20 #include <linux/slab.h>
21 #endif
22 #include <linux/err.h>
23 #include <linux/oid_registry.h>
24 #include <crypto/public_key.h>
25 #ifdef __UBOOT__
26 #include <crypto/pkcs7_parser.h>
27 #else
28 #include "pkcs7_parser.h"
29 #endif
30 #include "pkcs7.asn1.h"
31
32 MODULE_DESCRIPTION("PKCS#7 parser");
33 MODULE_AUTHOR("Red Hat, Inc.");
34 MODULE_LICENSE("GPL");
35
36 struct pkcs7_parse_context {
37 struct pkcs7_message *msg; /* Message being constructed */
38 struct pkcs7_signed_info *sinfo; /* SignedInfo being constructed */
39 struct pkcs7_signed_info **ppsinfo;
40 struct x509_certificate *certs; /* Certificate cache */
41 struct x509_certificate **ppcerts;
42 unsigned long data; /* Start of data */
43 enum OID last_oid; /* Last OID encountered */
44 unsigned x509_index;
45 unsigned sinfo_index;
46 const void *raw_serial;
47 unsigned raw_serial_size;
48 unsigned raw_issuer_size;
49 const void *raw_issuer;
50 const void *raw_skid;
51 unsigned raw_skid_size;
52 bool expect_skid;
53 };
54
55 /*
56 * Free a signed information block.
57 */
pkcs7_free_signed_info(struct pkcs7_signed_info * sinfo)58 static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo)
59 {
60 if (sinfo) {
61 public_key_signature_free(sinfo->sig);
62 kfree(sinfo);
63 }
64 }
65
66 /**
67 * pkcs7_free_message - Free a PKCS#7 message
68 * @pkcs7: The PKCS#7 message to free
69 */
pkcs7_free_message(struct pkcs7_message * pkcs7)70 void pkcs7_free_message(struct pkcs7_message *pkcs7)
71 {
72 struct x509_certificate *cert;
73 struct pkcs7_signed_info *sinfo;
74
75 if (pkcs7) {
76 while (pkcs7->certs) {
77 cert = pkcs7->certs;
78 pkcs7->certs = cert->next;
79 x509_free_certificate(cert);
80 }
81 while (pkcs7->crl) {
82 cert = pkcs7->crl;
83 pkcs7->crl = cert->next;
84 x509_free_certificate(cert);
85 }
86 while (pkcs7->signed_infos) {
87 sinfo = pkcs7->signed_infos;
88 pkcs7->signed_infos = sinfo->next;
89 pkcs7_free_signed_info(sinfo);
90 }
91 kfree(pkcs7);
92 }
93 }
94 EXPORT_SYMBOL_GPL(pkcs7_free_message);
95
96 /*
97 * Check authenticatedAttributes are provided or not provided consistently.
98 */
pkcs7_check_authattrs(struct pkcs7_message * msg)99 static int pkcs7_check_authattrs(struct pkcs7_message *msg)
100 {
101 struct pkcs7_signed_info *sinfo;
102 bool want = false;
103
104 sinfo = msg->signed_infos;
105 if (!sinfo)
106 goto inconsistent;
107
108 if (sinfo->authattrs) {
109 want = true;
110 msg->have_authattrs = true;
111 }
112
113 for (sinfo = sinfo->next; sinfo; sinfo = sinfo->next)
114 if (!!sinfo->authattrs != want)
115 goto inconsistent;
116 return 0;
117
118 inconsistent:
119 pr_warn("Inconsistently supplied authAttrs\n");
120 return -EINVAL;
121 }
122
123 /**
124 * pkcs7_parse_message - Parse a PKCS#7 message
125 * @data: The raw binary ASN.1 encoded message to be parsed
126 * @datalen: The size of the encoded message
127 */
pkcs7_parse_message(const void * data,size_t datalen)128 struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen)
129 {
130 struct pkcs7_parse_context *ctx;
131 struct pkcs7_message *msg = ERR_PTR(-ENOMEM);
132 int ret;
133
134 ctx = kzalloc(sizeof(struct pkcs7_parse_context), GFP_KERNEL);
135 if (!ctx)
136 goto out_no_ctx;
137 ctx->msg = kzalloc(sizeof(struct pkcs7_message), GFP_KERNEL);
138 if (!ctx->msg)
139 goto out_no_msg;
140 ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
141 if (!ctx->sinfo)
142 goto out_no_sinfo;
143 ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature),
144 GFP_KERNEL);
145 if (!ctx->sinfo->sig)
146 goto out_no_sig;
147
148 ctx->data = (unsigned long)data;
149 ctx->ppcerts = &ctx->certs;
150 ctx->ppsinfo = &ctx->msg->signed_infos;
151
152 /* Attempt to decode the signature */
153 ret = asn1_ber_decoder(&pkcs7_decoder, ctx, data, datalen);
154 if (ret < 0) {
155 msg = ERR_PTR(ret);
156 goto out;
157 }
158
159 ret = pkcs7_check_authattrs(ctx->msg);
160 if (ret < 0) {
161 msg = ERR_PTR(ret);
162 goto out;
163 }
164
165 msg = ctx->msg;
166 ctx->msg = NULL;
167
168 out:
169 while (ctx->certs) {
170 struct x509_certificate *cert = ctx->certs;
171 ctx->certs = cert->next;
172 x509_free_certificate(cert);
173 }
174 out_no_sig:
175 pkcs7_free_signed_info(ctx->sinfo);
176 out_no_sinfo:
177 pkcs7_free_message(ctx->msg);
178 out_no_msg:
179 kfree(ctx);
180 out_no_ctx:
181 return msg;
182 }
183 EXPORT_SYMBOL_GPL(pkcs7_parse_message);
184
185 /*
186 * Note an OID when we find one for later processing when we know how
187 * to interpret it.
188 */
pkcs7_note_OID(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)189 int pkcs7_note_OID(void *context, size_t hdrlen,
190 unsigned char tag,
191 const void *value, size_t vlen)
192 {
193 struct pkcs7_parse_context *ctx = context;
194
195 ctx->last_oid = look_up_OID(value, vlen);
196 if (ctx->last_oid == OID__NR) {
197 char buffer[50];
198 sprint_oid(value, vlen, buffer, sizeof(buffer));
199 printk("PKCS7: Unknown OID: [%lu] %s\n",
200 (unsigned long)value - ctx->data, buffer);
201 }
202 return 0;
203 }
204
205 /*
206 * Note the digest algorithm for the signature.
207 */
pkcs7_sig_note_digest_algo(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)208 int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen,
209 unsigned char tag,
210 const void *value, size_t vlen)
211 {
212 struct pkcs7_parse_context *ctx = context;
213
214 switch (ctx->last_oid) {
215 case OID_md4:
216 ctx->sinfo->sig->hash_algo = "md4";
217 break;
218 case OID_md5:
219 ctx->sinfo->sig->hash_algo = "md5";
220 break;
221 case OID_sha1:
222 ctx->sinfo->sig->hash_algo = "sha1";
223 break;
224 case OID_sha256:
225 ctx->sinfo->sig->hash_algo = "sha256";
226 break;
227 case OID_sha384:
228 ctx->sinfo->sig->hash_algo = "sha384";
229 break;
230 case OID_sha512:
231 ctx->sinfo->sig->hash_algo = "sha512";
232 break;
233 case OID_sha224:
234 ctx->sinfo->sig->hash_algo = "sha224";
235 break;
236 default:
237 printk("Unsupported digest algo: %u\n", ctx->last_oid);
238 return -ENOPKG;
239 }
240 return 0;
241 }
242
243 /*
244 * Note the public key algorithm for the signature.
245 */
pkcs7_sig_note_pkey_algo(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)246 int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen,
247 unsigned char tag,
248 const void *value, size_t vlen)
249 {
250 struct pkcs7_parse_context *ctx = context;
251
252 switch (ctx->last_oid) {
253 case OID_rsaEncryption:
254 ctx->sinfo->sig->pkey_algo = "rsa";
255 ctx->sinfo->sig->encoding = "pkcs1";
256 break;
257 default:
258 printk("Unsupported pkey algo: %u\n", ctx->last_oid);
259 return -ENOPKG;
260 }
261 return 0;
262 }
263
264 /*
265 * We only support signed data [RFC2315 sec 9].
266 */
pkcs7_check_content_type(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)267 int pkcs7_check_content_type(void *context, size_t hdrlen,
268 unsigned char tag,
269 const void *value, size_t vlen)
270 {
271 struct pkcs7_parse_context *ctx = context;
272
273 if (ctx->last_oid != OID_signed_data) {
274 pr_warn("Only support pkcs7_signedData type\n");
275 return -EINVAL;
276 }
277
278 return 0;
279 }
280
281 /*
282 * Note the SignedData version
283 */
pkcs7_note_signeddata_version(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)284 int pkcs7_note_signeddata_version(void *context, size_t hdrlen,
285 unsigned char tag,
286 const void *value, size_t vlen)
287 {
288 struct pkcs7_parse_context *ctx = context;
289 unsigned version;
290
291 if (vlen != 1)
292 goto unsupported;
293
294 ctx->msg->version = version = *(const u8 *)value;
295 switch (version) {
296 case 1:
297 /* PKCS#7 SignedData [RFC2315 sec 9.1]
298 * CMS ver 1 SignedData [RFC5652 sec 5.1]
299 */
300 break;
301 case 3:
302 /* CMS ver 3 SignedData [RFC2315 sec 5.1] */
303 break;
304 default:
305 goto unsupported;
306 }
307
308 return 0;
309
310 unsupported:
311 pr_warn("Unsupported SignedData version\n");
312 return -EINVAL;
313 }
314
315 /*
316 * Note the SignerInfo version
317 */
pkcs7_note_signerinfo_version(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)318 int pkcs7_note_signerinfo_version(void *context, size_t hdrlen,
319 unsigned char tag,
320 const void *value, size_t vlen)
321 {
322 struct pkcs7_parse_context *ctx = context;
323 unsigned version;
324
325 if (vlen != 1)
326 goto unsupported;
327
328 version = *(const u8 *)value;
329 switch (version) {
330 case 1:
331 /* PKCS#7 SignerInfo [RFC2315 sec 9.2]
332 * CMS ver 1 SignerInfo [RFC5652 sec 5.3]
333 */
334 if (ctx->msg->version != 1)
335 goto version_mismatch;
336 ctx->expect_skid = false;
337 break;
338 case 3:
339 /* CMS ver 3 SignerInfo [RFC2315 sec 5.3] */
340 if (ctx->msg->version == 1)
341 goto version_mismatch;
342 ctx->expect_skid = true;
343 break;
344 default:
345 goto unsupported;
346 }
347
348 return 0;
349
350 unsupported:
351 pr_warn("Unsupported SignerInfo version\n");
352 return -EINVAL;
353 version_mismatch:
354 pr_warn("SignedData-SignerInfo version mismatch\n");
355 return -EBADMSG;
356 }
357
358 /*
359 * Extract a certificate and store it in the context.
360 */
pkcs7_extract_cert(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)361 int pkcs7_extract_cert(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 struct x509_certificate *x509;
367
368 if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) {
369 pr_debug("Cert began with tag %02x at %lu\n",
370 tag, (unsigned long)ctx - ctx->data);
371 return -EBADMSG;
372 }
373
374 /* We have to correct for the header so that the X.509 parser can start
375 * from the beginning. Note that since X.509 stipulates DER, there
376 * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which
377 * stipulates BER).
378 */
379 value -= hdrlen;
380 vlen += hdrlen;
381
382 if (((u8*)value)[1] == 0x80)
383 vlen += 2; /* Indefinite length - there should be an EOC */
384
385 x509 = x509_cert_parse(value, vlen);
386 if (IS_ERR(x509))
387 return PTR_ERR(x509);
388
389 x509->index = ++ctx->x509_index;
390 pr_debug("Got cert %u for %s\n", x509->index, x509->subject);
391 pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data);
392
393 *ctx->ppcerts = x509;
394 ctx->ppcerts = &x509->next;
395 return 0;
396 }
397
398 /*
399 * Save the certificate list
400 */
pkcs7_note_certificate_list(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)401 int pkcs7_note_certificate_list(void *context, size_t hdrlen,
402 unsigned char tag,
403 const void *value, size_t vlen)
404 {
405 struct pkcs7_parse_context *ctx = context;
406
407 pr_devel("Got cert list (%02x)\n", tag);
408
409 *ctx->ppcerts = ctx->msg->certs;
410 ctx->msg->certs = ctx->certs;
411 ctx->certs = NULL;
412 ctx->ppcerts = &ctx->certs;
413 return 0;
414 }
415
416 /*
417 * Note the content type.
418 */
pkcs7_note_content(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)419 int pkcs7_note_content(void *context, size_t hdrlen,
420 unsigned char tag,
421 const void *value, size_t vlen)
422 {
423 struct pkcs7_parse_context *ctx = context;
424
425 if (ctx->last_oid != OID_data &&
426 ctx->last_oid != OID_msIndirectData) {
427 pr_warn("Unsupported data type %d\n", ctx->last_oid);
428 return -EINVAL;
429 }
430
431 ctx->msg->data_type = ctx->last_oid;
432 return 0;
433 }
434
435 /*
436 * Extract the data from the message and store that and its content type OID in
437 * the context.
438 */
pkcs7_note_data(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)439 int pkcs7_note_data(void *context, size_t hdrlen,
440 unsigned char tag,
441 const void *value, size_t vlen)
442 {
443 struct pkcs7_parse_context *ctx = context;
444
445 pr_debug("Got data\n");
446
447 ctx->msg->data = value;
448 ctx->msg->data_len = vlen;
449 ctx->msg->data_hdrlen = hdrlen;
450 return 0;
451 }
452
453 /*
454 * Parse authenticated attributes.
455 */
pkcs7_sig_note_authenticated_attr(void * context,size_t hdrlen,unsigned char tag,const void * value,size_t vlen)456 int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen,
457 unsigned char tag,
458 const void *value, size_t vlen)
459 {
460 struct pkcs7_parse_context *ctx = context;
461 struct pkcs7_signed_info *sinfo = ctx->sinfo;
462 enum OID content_type;
463
464 pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
465
466 switch (ctx->last_oid) {
467 case OID_contentType:
468 if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set))
469 goto repeated;
470 content_type = look_up_OID(value, vlen);
471 if (content_type != ctx->msg->data_type) {
472 pr_warn("Mismatch between global data type (%d) and sinfo %u (%d)\n",
473 ctx->msg->data_type, sinfo->index,
474 content_type);
475 return -EBADMSG;
476 }
477 return 0;
478
479 case OID_signingTime:
480 if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set))
481 goto repeated;
482 /* Should we check that the signing time is consistent
483 * with the signer's X.509 cert?
484 */
485 return x509_decode_time(&sinfo->signing_time,
486 hdrlen, tag, value, vlen);
487
488 case OID_messageDigest:
489 if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set))
490 goto repeated;
491 if (tag != ASN1_OTS)
492 return -EBADMSG;
493 sinfo->msgdigest = value;
494 sinfo->msgdigest_len = vlen;
495 return 0;
496
497 case OID_smimeCapabilites:
498 if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set))
499 goto repeated;
500 #ifdef __UBOOT__ /* OID_data is needed for authenticated UEFI variables */
501 if (ctx->msg->data_type != OID_msIndirectData &&
502 ctx->msg->data_type != OID_data) {
503 #else
504 if (ctx->msg->data_type != OID_msIndirectData) {
505 #endif
506 pr_warn("S/MIME Caps only allowed with Authenticode\n");
507 return -EKEYREJECTED;
508 }
509 return 0;
510
511 /* Microsoft SpOpusInfo seems to be contain cont[0] 16-bit BE
512 * char URLs and cont[1] 8-bit char URLs.
513 *
514 * Microsoft StatementType seems to contain a list of OIDs that
515 * are also used as extendedKeyUsage types in X.509 certs.
516 */
517 case OID_msSpOpusInfo:
518 if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set))
519 goto repeated;
520 goto authenticode_check;
521 case OID_msStatementType:
522 if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set))
523 goto repeated;
524 authenticode_check:
525 if (ctx->msg->data_type != OID_msIndirectData) {
526 pr_warn("Authenticode AuthAttrs only allowed with Authenticode\n");
527 return -EKEYREJECTED;
528 }
529 /* I'm not sure how to validate these */
530 return 0;
531 default:
532 return 0;
533 }
534
535 repeated:
536 /* We permit max one item per AuthenticatedAttribute and no repeats */
537 pr_warn("Repeated/multivalue AuthAttrs not permitted\n");
538 return -EKEYREJECTED;
539 }
540
541 /*
542 * Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3]
543 */
544 int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen,
545 unsigned char tag,
546 const void *value, size_t vlen)
547 {
548 struct pkcs7_parse_context *ctx = context;
549 struct pkcs7_signed_info *sinfo = ctx->sinfo;
550
551 if (!test_bit(sinfo_has_content_type, &sinfo->aa_set) ||
552 !test_bit(sinfo_has_message_digest, &sinfo->aa_set)) {
553 pr_warn("Missing required AuthAttr\n");
554 return -EBADMSG;
555 }
556
557 if (ctx->msg->data_type != OID_msIndirectData &&
558 test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) {
559 pr_warn("Unexpected Authenticode AuthAttr\n");
560 return -EBADMSG;
561 }
562
563 /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */
564 sinfo->authattrs = value - (hdrlen - 1);
565 sinfo->authattrs_len = vlen + (hdrlen - 1);
566 return 0;
567 }
568
569 /*
570 * Note the issuing certificate serial number
571 */
572 int pkcs7_sig_note_serial(void *context, size_t hdrlen,
573 unsigned char tag,
574 const void *value, size_t vlen)
575 {
576 struct pkcs7_parse_context *ctx = context;
577 ctx->raw_serial = value;
578 ctx->raw_serial_size = vlen;
579 return 0;
580 }
581
582 /*
583 * Note the issuer's name
584 */
585 int pkcs7_sig_note_issuer(void *context, size_t hdrlen,
586 unsigned char tag,
587 const void *value, size_t vlen)
588 {
589 struct pkcs7_parse_context *ctx = context;
590 ctx->raw_issuer = value;
591 ctx->raw_issuer_size = vlen;
592 return 0;
593 }
594
595 /*
596 * Note the issuing cert's subjectKeyIdentifier
597 */
598 int pkcs7_sig_note_skid(void *context, size_t hdrlen,
599 unsigned char tag,
600 const void *value, size_t vlen)
601 {
602 struct pkcs7_parse_context *ctx = context;
603
604 pr_devel("SKID: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
605
606 ctx->raw_skid = value;
607 ctx->raw_skid_size = vlen;
608 return 0;
609 }
610
611 /*
612 * Note the signature data
613 */
614 int pkcs7_sig_note_signature(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
620 ctx->sinfo->sig->s = kmemdup(value, vlen, GFP_KERNEL);
621 if (!ctx->sinfo->sig->s)
622 return -ENOMEM;
623
624 ctx->sinfo->sig->s_size = vlen;
625 return 0;
626 }
627
628 /*
629 * Note a signature information block
630 */
631 int pkcs7_note_signed_info(void *context, size_t hdrlen,
632 unsigned char tag,
633 const void *value, size_t vlen)
634 {
635 struct pkcs7_parse_context *ctx = context;
636 struct pkcs7_signed_info *sinfo = ctx->sinfo;
637 struct asymmetric_key_id *kid;
638
639 if (ctx->msg->data_type == OID_msIndirectData && !sinfo->authattrs) {
640 pr_warn("Authenticode requires AuthAttrs\n");
641 return -EBADMSG;
642 }
643
644 /* Generate cert issuer + serial number key ID */
645 if (!ctx->expect_skid) {
646 kid = asymmetric_key_generate_id(ctx->raw_serial,
647 ctx->raw_serial_size,
648 ctx->raw_issuer,
649 ctx->raw_issuer_size);
650 } else {
651 kid = asymmetric_key_generate_id(ctx->raw_skid,
652 ctx->raw_skid_size,
653 "", 0);
654 }
655 if (IS_ERR(kid))
656 return PTR_ERR(kid);
657
658 pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data);
659
660 sinfo->sig->auth_ids[0] = kid;
661 sinfo->index = ++ctx->sinfo_index;
662 *ctx->ppsinfo = sinfo;
663 ctx->ppsinfo = &sinfo->next;
664 ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
665 if (!ctx->sinfo)
666 return -ENOMEM;
667 ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature),
668 GFP_KERNEL);
669 if (!ctx->sinfo->sig)
670 return -ENOMEM;
671 return 0;
672 }
673