1
2
3
4
5
6
7
8
9#include <keys/asymmetric-subtype.h>
10#include <keys/asymmetric-parser.h>
11#include <crypto/public_key.h>
12#include <linux/seq_file.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/ctype.h>
16#include <keys/system_keyring.h>
17#include <keys/user-type.h>
18#include "asymmetric_keys.h"
19
20MODULE_LICENSE("GPL");
21
22const char *const key_being_used_for[NR__KEY_BEING_USED_FOR] = {
23 [VERIFYING_MODULE_SIGNATURE] = "mod sig",
24 [VERIFYING_FIRMWARE_SIGNATURE] = "firmware sig",
25 [VERIFYING_KEXEC_PE_SIGNATURE] = "kexec PE sig",
26 [VERIFYING_KEY_SIGNATURE] = "key sig",
27 [VERIFYING_KEY_SELF_SIGNATURE] = "key self sig",
28 [VERIFYING_UNSPECIFIED_SIGNATURE] = "unspec sig",
29};
30EXPORT_SYMBOL_GPL(key_being_used_for);
31
32static LIST_HEAD(asymmetric_key_parsers);
33static DECLARE_RWSEM(asymmetric_key_parsers_sem);
34
35
36
37
38
39
40
41
42
43
44
45
46struct key *find_asymmetric_key(struct key *keyring,
47 const struct asymmetric_key_id *id_0,
48 const struct asymmetric_key_id *id_1,
49 bool partial)
50{
51 struct key *key;
52 key_ref_t ref;
53 const char *lookup;
54 char *req, *p;
55 int len;
56
57 BUG_ON(!id_0 && !id_1);
58
59 if (id_0) {
60 lookup = id_0->data;
61 len = id_0->len;
62 } else {
63 lookup = id_1->data;
64 len = id_1->len;
65 }
66
67
68 p = req = kmalloc(2 + 1 + len * 2 + 1, GFP_KERNEL);
69 if (!req)
70 return ERR_PTR(-ENOMEM);
71
72 if (partial) {
73 *p++ = 'i';
74 *p++ = 'd';
75 } else {
76 *p++ = 'e';
77 *p++ = 'x';
78 }
79 *p++ = ':';
80 p = bin2hex(p, lookup, len);
81 *p = 0;
82
83 pr_debug("Look up: \"%s\"\n", req);
84
85 ref = keyring_search(make_key_ref(keyring, 1),
86 &key_type_asymmetric, req, true);
87 if (IS_ERR(ref))
88 pr_debug("Request for key '%s' err %ld\n", req, PTR_ERR(ref));
89 kfree(req);
90
91 if (IS_ERR(ref)) {
92 switch (PTR_ERR(ref)) {
93
94 case -EACCES:
95 case -ENOTDIR:
96 case -EAGAIN:
97 return ERR_PTR(-ENOKEY);
98 default:
99 return ERR_CAST(ref);
100 }
101 }
102
103 key = key_ref_to_ptr(ref);
104 if (id_0 && id_1) {
105 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
106
107 if (!kids->id[1]) {
108 pr_debug("First ID matches, but second is missing\n");
109 goto reject;
110 }
111 if (!asymmetric_key_id_same(id_1, kids->id[1])) {
112 pr_debug("First ID matches, but second does not\n");
113 goto reject;
114 }
115 }
116
117 pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key));
118 return key;
119
120reject:
121 key_put(key);
122 return ERR_PTR(-EKEYREJECTED);
123}
124EXPORT_SYMBOL_GPL(find_asymmetric_key);
125
126
127
128
129
130
131
132
133
134
135struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
136 size_t len_1,
137 const void *val_2,
138 size_t len_2)
139{
140 struct asymmetric_key_id *kid;
141
142 kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
143 GFP_KERNEL);
144 if (!kid)
145 return ERR_PTR(-ENOMEM);
146 kid->len = len_1 + len_2;
147 memcpy(kid->data, val_1, len_1);
148 memcpy(kid->data + len_1, val_2, len_2);
149 return kid;
150}
151EXPORT_SYMBOL_GPL(asymmetric_key_generate_id);
152
153
154
155
156
157
158bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
159 const struct asymmetric_key_id *kid2)
160{
161 if (!kid1 || !kid2)
162 return false;
163 if (kid1->len != kid2->len)
164 return false;
165 return memcmp(kid1->data, kid2->data, kid1->len) == 0;
166}
167EXPORT_SYMBOL_GPL(asymmetric_key_id_same);
168
169
170
171
172
173
174
175bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
176 const struct asymmetric_key_id *kid2)
177{
178 if (!kid1 || !kid2)
179 return false;
180 if (kid1->len < kid2->len)
181 return false;
182 return memcmp(kid1->data + (kid1->len - kid2->len),
183 kid2->data, kid2->len) == 0;
184}
185EXPORT_SYMBOL_GPL(asymmetric_key_id_partial);
186
187
188
189
190
191
192
193static bool asymmetric_match_key_ids(
194 const struct asymmetric_key_ids *kids,
195 const struct asymmetric_key_id *match_id,
196 bool (*match)(const struct asymmetric_key_id *kid1,
197 const struct asymmetric_key_id *kid2))
198{
199 int i;
200
201 if (!kids || !match_id)
202 return false;
203 for (i = 0; i < ARRAY_SIZE(kids->id); i++)
204 if (match(kids->id[i], match_id))
205 return true;
206 return false;
207}
208
209
210inline int __asymmetric_key_hex_to_key_id(const char *id,
211 struct asymmetric_key_id *match_id,
212 size_t hexlen)
213{
214 match_id->len = hexlen;
215 return hex2bin(match_id->data, id, hexlen);
216}
217
218
219
220
221
222struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
223{
224 struct asymmetric_key_id *match_id;
225 size_t asciihexlen;
226 int ret;
227
228 if (!*id)
229 return ERR_PTR(-EINVAL);
230 asciihexlen = strlen(id);
231 if (asciihexlen & 1)
232 return ERR_PTR(-EINVAL);
233
234 match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2,
235 GFP_KERNEL);
236 if (!match_id)
237 return ERR_PTR(-ENOMEM);
238 ret = __asymmetric_key_hex_to_key_id(id, match_id, asciihexlen / 2);
239 if (ret < 0) {
240 kfree(match_id);
241 return ERR_PTR(-EINVAL);
242 }
243 return match_id;
244}
245
246
247
248
249static bool asymmetric_key_cmp(const struct key *key,
250 const struct key_match_data *match_data)
251{
252 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
253 const struct asymmetric_key_id *match_id = match_data->preparsed;
254
255 return asymmetric_match_key_ids(kids, match_id,
256 asymmetric_key_id_same);
257}
258
259
260
261
262static bool asymmetric_key_cmp_partial(const struct key *key,
263 const struct key_match_data *match_data)
264{
265 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
266 const struct asymmetric_key_id *match_id = match_data->preparsed;
267
268 return asymmetric_match_key_ids(kids, match_id,
269 asymmetric_key_id_partial);
270}
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285static int asymmetric_key_match_preparse(struct key_match_data *match_data)
286{
287 struct asymmetric_key_id *match_id;
288 const char *spec = match_data->raw_data;
289 const char *id;
290 bool (*cmp)(const struct key *, const struct key_match_data *) =
291 asymmetric_key_cmp;
292
293 if (!spec || !*spec)
294 return -EINVAL;
295 if (spec[0] == 'i' &&
296 spec[1] == 'd' &&
297 spec[2] == ':') {
298 id = spec + 3;
299 cmp = asymmetric_key_cmp_partial;
300 } else if (spec[0] == 'e' &&
301 spec[1] == 'x' &&
302 spec[2] == ':') {
303 id = spec + 3;
304 } else {
305 goto default_match;
306 }
307
308 match_id = asymmetric_key_hex_to_key_id(id);
309 if (IS_ERR(match_id))
310 return PTR_ERR(match_id);
311
312 match_data->preparsed = match_id;
313 match_data->cmp = cmp;
314 match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
315 return 0;
316
317default_match:
318 return 0;
319}
320
321
322
323
324static void asymmetric_key_match_free(struct key_match_data *match_data)
325{
326 kfree(match_data->preparsed);
327}
328
329
330
331
332static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
333{
334 const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
335 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
336 const struct asymmetric_key_id *kid;
337 const unsigned char *p;
338 int n;
339
340 seq_puts(m, key->description);
341
342 if (subtype) {
343 seq_puts(m, ": ");
344 subtype->describe(key, m);
345
346 if (kids && kids->id[1]) {
347 kid = kids->id[1];
348 seq_putc(m, ' ');
349 n = kid->len;
350 p = kid->data;
351 if (n > 4) {
352 p += n - 4;
353 n = 4;
354 }
355 seq_printf(m, "%*phN", n, p);
356 }
357
358 seq_puts(m, " [");
359
360 seq_putc(m, ']');
361 }
362}
363
364
365
366
367
368
369
370
371static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
372{
373 struct asymmetric_key_parser *parser;
374 int ret;
375
376 pr_devel("==>%s()\n", __func__);
377
378 if (prep->datalen == 0)
379 return -EINVAL;
380
381 down_read(&asymmetric_key_parsers_sem);
382
383 ret = -EBADMSG;
384 list_for_each_entry(parser, &asymmetric_key_parsers, link) {
385 pr_debug("Trying parser '%s'\n", parser->name);
386
387 ret = parser->parse(prep);
388 if (ret != -EBADMSG) {
389 pr_debug("Parser recognised the format (ret %d)\n",
390 ret);
391 break;
392 }
393 }
394
395 up_read(&asymmetric_key_parsers_sem);
396 pr_devel("<==%s() = %d\n", __func__, ret);
397 return ret;
398}
399
400
401
402
403static void asymmetric_key_free_kids(struct asymmetric_key_ids *kids)
404{
405 int i;
406
407 if (kids) {
408 for (i = 0; i < ARRAY_SIZE(kids->id); i++)
409 kfree(kids->id[i]);
410 kfree(kids);
411 }
412}
413
414
415
416
417static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
418{
419 struct asymmetric_key_subtype *subtype = prep->payload.data[asym_subtype];
420 struct asymmetric_key_ids *kids = prep->payload.data[asym_key_ids];
421
422 pr_devel("==>%s()\n", __func__);
423
424 if (subtype) {
425 subtype->destroy(prep->payload.data[asym_crypto],
426 prep->payload.data[asym_auth]);
427 module_put(subtype->owner);
428 }
429 asymmetric_key_free_kids(kids);
430 kfree(prep->description);
431}
432
433
434
435
436static void asymmetric_key_destroy(struct key *key)
437{
438 struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
439 struct asymmetric_key_ids *kids = key->payload.data[asym_key_ids];
440 void *data = key->payload.data[asym_crypto];
441 void *auth = key->payload.data[asym_auth];
442
443 key->payload.data[asym_crypto] = NULL;
444 key->payload.data[asym_subtype] = NULL;
445 key->payload.data[asym_key_ids] = NULL;
446 key->payload.data[asym_auth] = NULL;
447
448 if (subtype) {
449 subtype->destroy(data, auth);
450 module_put(subtype->owner);
451 }
452
453 asymmetric_key_free_kids(kids);
454}
455
456static struct key_restriction *asymmetric_restriction_alloc(
457 key_restrict_link_func_t check,
458 struct key *key)
459{
460 struct key_restriction *keyres =
461 kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
462
463 if (!keyres)
464 return ERR_PTR(-ENOMEM);
465
466 keyres->check = check;
467 keyres->key = key;
468 keyres->keytype = &key_type_asymmetric;
469
470 return keyres;
471}
472
473
474
475
476static struct key_restriction *asymmetric_lookup_restriction(
477 const char *restriction)
478{
479 char *restrict_method;
480 char *parse_buf;
481 char *next;
482 struct key_restriction *ret = ERR_PTR(-EINVAL);
483
484 if (strcmp("builtin_trusted", restriction) == 0)
485 return asymmetric_restriction_alloc(
486 restrict_link_by_builtin_trusted, NULL);
487
488 if (strcmp("builtin_and_secondary_trusted", restriction) == 0)
489 return asymmetric_restriction_alloc(
490 restrict_link_by_builtin_and_secondary_trusted, NULL);
491
492 parse_buf = kstrndup(restriction, PAGE_SIZE, GFP_KERNEL);
493 if (!parse_buf)
494 return ERR_PTR(-ENOMEM);
495
496 next = parse_buf;
497 restrict_method = strsep(&next, ":");
498
499 if ((strcmp(restrict_method, "key_or_keyring") == 0) && next) {
500 char *key_text;
501 key_serial_t serial;
502 struct key *key;
503 key_restrict_link_func_t link_fn =
504 restrict_link_by_key_or_keyring;
505 bool allow_null_key = false;
506
507 key_text = strsep(&next, ":");
508
509 if (next) {
510 if (strcmp(next, "chain") != 0)
511 goto out;
512
513 link_fn = restrict_link_by_key_or_keyring_chain;
514 allow_null_key = true;
515 }
516
517 if (kstrtos32(key_text, 0, &serial) < 0)
518 goto out;
519
520 if ((serial == 0) && allow_null_key) {
521 key = NULL;
522 } else {
523 key = key_lookup(serial);
524 if (IS_ERR(key)) {
525 ret = ERR_CAST(key);
526 goto out;
527 }
528 }
529
530 ret = asymmetric_restriction_alloc(link_fn, key);
531 if (IS_ERR(ret))
532 key_put(key);
533 }
534
535out:
536 kfree(parse_buf);
537 return ret;
538}
539
540int asymmetric_key_eds_op(struct kernel_pkey_params *params,
541 const void *in, void *out)
542{
543 const struct asymmetric_key_subtype *subtype;
544 struct key *key = params->key;
545 int ret;
546
547 pr_devel("==>%s()\n", __func__);
548
549 if (key->type != &key_type_asymmetric)
550 return -EINVAL;
551 subtype = asymmetric_key_subtype(key);
552 if (!subtype ||
553 !key->payload.data[0])
554 return -EINVAL;
555 if (!subtype->eds_op)
556 return -ENOTSUPP;
557
558 ret = subtype->eds_op(params, in, out);
559
560 pr_devel("<==%s() = %d\n", __func__, ret);
561 return ret;
562}
563
564static int asymmetric_key_verify_signature(struct kernel_pkey_params *params,
565 const void *in, const void *in2)
566{
567 struct public_key_signature sig = {
568 .s_size = params->in2_len,
569 .digest_size = params->in_len,
570 .encoding = params->encoding,
571 .hash_algo = params->hash_algo,
572 .digest = (void *)in,
573 .s = (void *)in2,
574 };
575
576 return verify_signature(params->key, &sig);
577}
578
579struct key_type key_type_asymmetric = {
580 .name = "asymmetric",
581 .preparse = asymmetric_key_preparse,
582 .free_preparse = asymmetric_key_free_preparse,
583 .instantiate = generic_key_instantiate,
584 .match_preparse = asymmetric_key_match_preparse,
585 .match_free = asymmetric_key_match_free,
586 .destroy = asymmetric_key_destroy,
587 .describe = asymmetric_key_describe,
588 .lookup_restriction = asymmetric_lookup_restriction,
589 .asym_query = query_asymmetric_key,
590 .asym_eds_op = asymmetric_key_eds_op,
591 .asym_verify_signature = asymmetric_key_verify_signature,
592};
593EXPORT_SYMBOL_GPL(key_type_asymmetric);
594
595
596
597
598
599int register_asymmetric_key_parser(struct asymmetric_key_parser *parser)
600{
601 struct asymmetric_key_parser *cursor;
602 int ret;
603
604 down_write(&asymmetric_key_parsers_sem);
605
606 list_for_each_entry(cursor, &asymmetric_key_parsers, link) {
607 if (strcmp(cursor->name, parser->name) == 0) {
608 pr_err("Asymmetric key parser '%s' already registered\n",
609 parser->name);
610 ret = -EEXIST;
611 goto out;
612 }
613 }
614
615 list_add_tail(&parser->link, &asymmetric_key_parsers);
616
617 pr_notice("Asymmetric key parser '%s' registered\n", parser->name);
618 ret = 0;
619
620out:
621 up_write(&asymmetric_key_parsers_sem);
622 return ret;
623}
624EXPORT_SYMBOL_GPL(register_asymmetric_key_parser);
625
626
627
628
629
630void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser)
631{
632 down_write(&asymmetric_key_parsers_sem);
633 list_del(&parser->link);
634 up_write(&asymmetric_key_parsers_sem);
635
636 pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name);
637}
638EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser);
639
640
641
642
643static int __init asymmetric_key_init(void)
644{
645 return register_key_type(&key_type_asymmetric);
646}
647
648static void __exit asymmetric_key_cleanup(void)
649{
650 unregister_key_type(&key_type_asymmetric);
651}
652
653module_init(asymmetric_key_init);
654module_exit(asymmetric_key_cleanup);
655