1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Asymmetric public-key cryptography key type
4 * See Documentation/crypto/asymmetric-keys.txt
6 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
7 * Written by David Howells (dhowells@redhat.com)
11 #include <dm/devres.h>
12 #include <keys/asymmetric-subtype.h>
13 #include <keys/asymmetric-parser.h>
15 #include <crypto/public_key.h>
17 #include <linux/bug.h>
18 #include <linux/compat.h>
19 #include <linux/ctype.h>
20 #include <linux/err.h>
21 #include <linux/string.h>
23 #include <linux/seq_file.h>
24 #include <linux/module.h>
25 #include <linux/slab.h>
26 #include <linux/ctype.h>
29 #include <keys/asymmetric-type.h>
31 #include <keys/system_keyring.h>
32 #include <keys/user-type.h>
33 #include "asymmetric_keys.h"
36 MODULE_LICENSE("GPL");
39 const char *const key_being_used_for[NR__KEY_BEING_USED_FOR] = {
40 [VERIFYING_MODULE_SIGNATURE] = "mod sig",
41 [VERIFYING_FIRMWARE_SIGNATURE] = "firmware sig",
42 [VERIFYING_KEXEC_PE_SIGNATURE] = "kexec PE sig",
43 [VERIFYING_KEY_SIGNATURE] = "key sig",
44 [VERIFYING_KEY_SELF_SIGNATURE] = "key self sig",
45 [VERIFYING_UNSPECIFIED_SIGNATURE] = "unspec sig",
47 EXPORT_SYMBOL_GPL(key_being_used_for);
49 static LIST_HEAD(asymmetric_key_parsers);
50 static DECLARE_RWSEM(asymmetric_key_parsers_sem);
53 * find_asymmetric_key - Find a key by ID.
54 * @keyring: The keys to search.
55 * @id_0: The first ID to look for or NULL.
56 * @id_1: The second ID to look for or NULL.
57 * @partial: Use partial match if true, exact if false.
59 * Find a key in the given keyring by identifier. The preferred identifier is
60 * the id_0 and the fallback identifier is the id_1. If both are given, the
61 * lookup is by the former, but the latter must also match.
63 struct key *find_asymmetric_key(struct key *keyring,
64 const struct asymmetric_key_id *id_0,
65 const struct asymmetric_key_id *id_1,
74 BUG_ON(!id_0 && !id_1);
84 /* Construct an identifier "id:<keyid>". */
85 p = req = kmalloc(2 + 1 + len * 2 + 1, GFP_KERNEL);
87 return ERR_PTR(-ENOMEM);
97 p = bin2hex(p, lookup, len);
100 pr_debug("Look up: \"%s\"\n", req);
102 ref = keyring_search(make_key_ref(keyring, 1),
103 &key_type_asymmetric, req, true);
105 pr_debug("Request for key '%s' err %ld\n", req, PTR_ERR(ref));
109 switch (PTR_ERR(ref)) {
110 /* Hide some search errors */
114 return ERR_PTR(-ENOKEY);
116 return ERR_CAST(ref);
120 key = key_ref_to_ptr(ref);
122 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
125 pr_debug("First ID matches, but second is missing\n");
128 if (!asymmetric_key_id_same(id_1, kids->id[1])) {
129 pr_debug("First ID matches, but second does not\n");
134 pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key));
139 return ERR_PTR(-EKEYREJECTED);
141 EXPORT_SYMBOL_GPL(find_asymmetric_key);
142 #endif /* !__UBOOT__ */
145 * asymmetric_key_generate_id: Construct an asymmetric key ID
146 * @val_1: First binary blob
147 * @len_1: Length of first binary blob
148 * @val_2: Second binary blob
149 * @len_2: Length of second binary blob
151 * Construct an asymmetric key ID from a pair of binary blobs.
153 struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
158 struct asymmetric_key_id *kid;
160 kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
163 return ERR_PTR(-ENOMEM);
164 kid->len = len_1 + len_2;
165 memcpy(kid->data, val_1, len_1);
166 memcpy(kid->data + len_1, val_2, len_2);
169 EXPORT_SYMBOL_GPL(asymmetric_key_generate_id);
172 * asymmetric_key_id_same - Return true if two asymmetric keys IDs are the same.
173 * @kid_1, @kid_2: The key IDs to compare
175 bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
176 const struct asymmetric_key_id *kid2)
180 if (kid1->len != kid2->len)
182 return memcmp(kid1->data, kid2->data, kid1->len) == 0;
184 EXPORT_SYMBOL_GPL(asymmetric_key_id_same);
187 * asymmetric_key_id_partial - Return true if two asymmetric keys IDs
189 * @kid_1, @kid_2: The key IDs to compare
191 bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
192 const struct asymmetric_key_id *kid2)
196 if (kid1->len < kid2->len)
198 return memcmp(kid1->data + (kid1->len - kid2->len),
199 kid2->data, kid2->len) == 0;
201 EXPORT_SYMBOL_GPL(asymmetric_key_id_partial);
205 * asymmetric_match_key_ids - Search asymmetric key IDs
206 * @kids: The list of key IDs to check
207 * @match_id: The key ID we're looking for
208 * @match: The match function to use
210 static bool asymmetric_match_key_ids(
211 const struct asymmetric_key_ids *kids,
212 const struct asymmetric_key_id *match_id,
213 bool (*match)(const struct asymmetric_key_id *kid1,
214 const struct asymmetric_key_id *kid2))
218 if (!kids || !match_id)
220 for (i = 0; i < ARRAY_SIZE(kids->id); i++)
221 if (match(kids->id[i], match_id))
226 /* helper function can be called directly with pre-allocated memory */
227 inline int __asymmetric_key_hex_to_key_id(const char *id,
228 struct asymmetric_key_id *match_id,
231 match_id->len = hexlen;
232 return hex2bin(match_id->data, id, hexlen);
236 * asymmetric_key_hex_to_key_id - Convert a hex string into a key ID.
237 * @id: The ID as a hex string.
239 struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
241 struct asymmetric_key_id *match_id;
246 return ERR_PTR(-EINVAL);
247 asciihexlen = strlen(id);
249 return ERR_PTR(-EINVAL);
251 match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2,
254 return ERR_PTR(-ENOMEM);
255 ret = __asymmetric_key_hex_to_key_id(id, match_id, asciihexlen / 2);
258 return ERR_PTR(-EINVAL);
264 * Match asymmetric keys by an exact match on an ID.
266 static bool asymmetric_key_cmp(const struct key *key,
267 const struct key_match_data *match_data)
269 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
270 const struct asymmetric_key_id *match_id = match_data->preparsed;
272 return asymmetric_match_key_ids(kids, match_id,
273 asymmetric_key_id_same);
277 * Match asymmetric keys by a partial match on an IDs.
279 static bool asymmetric_key_cmp_partial(const struct key *key,
280 const struct key_match_data *match_data)
282 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
283 const struct asymmetric_key_id *match_id = match_data->preparsed;
285 return asymmetric_match_key_ids(kids, match_id,
286 asymmetric_key_id_partial);
290 * Preparse the match criterion. If we don't set lookup_type and cmp,
291 * the default will be an exact match on the key description.
293 * There are some specifiers for matching key IDs rather than by the key
296 * "id:<id>" - find a key by partial match on any available ID
297 * "ex:<id>" - find a key by exact match on any available ID
299 * These have to be searched by iteration rather than by direct lookup because
300 * the key is hashed according to its description.
302 static int asymmetric_key_match_preparse(struct key_match_data *match_data)
304 struct asymmetric_key_id *match_id;
305 const char *spec = match_data->raw_data;
307 bool (*cmp)(const struct key *, const struct key_match_data *) =
312 if (spec[0] == 'i' &&
316 cmp = asymmetric_key_cmp_partial;
317 } else if (spec[0] == 'e' &&
325 match_id = asymmetric_key_hex_to_key_id(id);
326 if (IS_ERR(match_id))
327 return PTR_ERR(match_id);
329 match_data->preparsed = match_id;
330 match_data->cmp = cmp;
331 match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
339 * Free the preparsed the match criterion.
341 static void asymmetric_key_match_free(struct key_match_data *match_data)
343 kfree(match_data->preparsed);
347 * Describe the asymmetric key
349 static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
351 const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
352 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
353 const struct asymmetric_key_id *kid;
354 const unsigned char *p;
357 seq_puts(m, key->description);
361 subtype->describe(key, m);
363 if (kids && kids->id[1]) {
372 seq_printf(m, "%*phN", n, p);
376 /* put something here to indicate the key's capabilities */
382 * Preparse a asymmetric payload to get format the contents appropriately for the
383 * internal payload to cut down on the number of scans of the data performed.
385 * We also generate a proposed description from the contents of the key that
386 * can be used to name the key if the user doesn't want to provide one.
388 static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
390 struct asymmetric_key_parser *parser;
393 pr_devel("==>%s()\n", __func__);
395 if (prep->datalen == 0)
398 down_read(&asymmetric_key_parsers_sem);
401 list_for_each_entry(parser, &asymmetric_key_parsers, link) {
402 pr_debug("Trying parser '%s'\n", parser->name);
404 ret = parser->parse(prep);
405 if (ret != -EBADMSG) {
406 pr_debug("Parser recognised the format (ret %d)\n",
412 up_read(&asymmetric_key_parsers_sem);
413 pr_devel("<==%s() = %d\n", __func__, ret);
418 * Clean up the key ID list
420 static void asymmetric_key_free_kids(struct asymmetric_key_ids *kids)
425 for (i = 0; i < ARRAY_SIZE(kids->id); i++)
432 * Clean up the preparse data
434 static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
436 struct asymmetric_key_subtype *subtype = prep->payload.data[asym_subtype];
437 struct asymmetric_key_ids *kids = prep->payload.data[asym_key_ids];
439 pr_devel("==>%s()\n", __func__);
442 subtype->destroy(prep->payload.data[asym_crypto],
443 prep->payload.data[asym_auth]);
444 module_put(subtype->owner);
446 asymmetric_key_free_kids(kids);
447 kfree(prep->description);
451 * dispose of the data dangling from the corpse of a asymmetric key
453 static void asymmetric_key_destroy(struct key *key)
455 struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
456 struct asymmetric_key_ids *kids = key->payload.data[asym_key_ids];
457 void *data = key->payload.data[asym_crypto];
458 void *auth = key->payload.data[asym_auth];
460 key->payload.data[asym_crypto] = NULL;
461 key->payload.data[asym_subtype] = NULL;
462 key->payload.data[asym_key_ids] = NULL;
463 key->payload.data[asym_auth] = NULL;
466 subtype->destroy(data, auth);
467 module_put(subtype->owner);
470 asymmetric_key_free_kids(kids);
473 static struct key_restriction *asymmetric_restriction_alloc(
474 key_restrict_link_func_t check,
477 struct key_restriction *keyres =
478 kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
481 return ERR_PTR(-ENOMEM);
483 keyres->check = check;
485 keyres->keytype = &key_type_asymmetric;
491 * look up keyring restrict functions for asymmetric keys
493 static struct key_restriction *asymmetric_lookup_restriction(
494 const char *restriction)
496 char *restrict_method;
499 struct key_restriction *ret = ERR_PTR(-EINVAL);
501 if (strcmp("builtin_trusted", restriction) == 0)
502 return asymmetric_restriction_alloc(
503 restrict_link_by_builtin_trusted, NULL);
505 if (strcmp("builtin_and_secondary_trusted", restriction) == 0)
506 return asymmetric_restriction_alloc(
507 restrict_link_by_builtin_and_secondary_trusted, NULL);
509 parse_buf = kstrndup(restriction, PAGE_SIZE, GFP_KERNEL);
511 return ERR_PTR(-ENOMEM);
514 restrict_method = strsep(&next, ":");
516 if ((strcmp(restrict_method, "key_or_keyring") == 0) && next) {
520 key_restrict_link_func_t link_fn =
521 restrict_link_by_key_or_keyring;
522 bool allow_null_key = false;
524 key_text = strsep(&next, ":");
527 if (strcmp(next, "chain") != 0)
530 link_fn = restrict_link_by_key_or_keyring_chain;
531 allow_null_key = true;
534 if (kstrtos32(key_text, 0, &serial) < 0)
537 if ((serial == 0) && allow_null_key) {
540 key = key_lookup(serial);
547 ret = asymmetric_restriction_alloc(link_fn, key);
557 int asymmetric_key_eds_op(struct kernel_pkey_params *params,
558 const void *in, void *out)
560 const struct asymmetric_key_subtype *subtype;
561 struct key *key = params->key;
564 pr_devel("==>%s()\n", __func__);
566 if (key->type != &key_type_asymmetric)
568 subtype = asymmetric_key_subtype(key);
570 !key->payload.data[0])
572 if (!subtype->eds_op)
575 ret = subtype->eds_op(params, in, out);
577 pr_devel("<==%s() = %d\n", __func__, ret);
581 static int asymmetric_key_verify_signature(struct kernel_pkey_params *params,
582 const void *in, const void *in2)
584 struct public_key_signature sig = {
585 .s_size = params->in2_len,
586 .digest_size = params->in_len,
587 .encoding = params->encoding,
588 .hash_algo = params->hash_algo,
589 .digest = (void *)in,
593 return verify_signature(params->key, &sig);
596 struct key_type key_type_asymmetric = {
597 .name = "asymmetric",
598 .preparse = asymmetric_key_preparse,
599 .free_preparse = asymmetric_key_free_preparse,
600 .instantiate = generic_key_instantiate,
601 .match_preparse = asymmetric_key_match_preparse,
602 .match_free = asymmetric_key_match_free,
603 .destroy = asymmetric_key_destroy,
604 .describe = asymmetric_key_describe,
605 .lookup_restriction = asymmetric_lookup_restriction,
606 .asym_query = query_asymmetric_key,
607 .asym_eds_op = asymmetric_key_eds_op,
608 .asym_verify_signature = asymmetric_key_verify_signature,
610 EXPORT_SYMBOL_GPL(key_type_asymmetric);
613 * register_asymmetric_key_parser - Register a asymmetric key blob parser
614 * @parser: The parser to register
616 int register_asymmetric_key_parser(struct asymmetric_key_parser *parser)
618 struct asymmetric_key_parser *cursor;
621 down_write(&asymmetric_key_parsers_sem);
623 list_for_each_entry(cursor, &asymmetric_key_parsers, link) {
624 if (strcmp(cursor->name, parser->name) == 0) {
625 pr_err("Asymmetric key parser '%s' already registered\n",
632 list_add_tail(&parser->link, &asymmetric_key_parsers);
634 pr_notice("Asymmetric key parser '%s' registered\n", parser->name);
638 up_write(&asymmetric_key_parsers_sem);
641 EXPORT_SYMBOL_GPL(register_asymmetric_key_parser);
644 * unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser
645 * @parser: The parser to unregister
647 void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser)
649 down_write(&asymmetric_key_parsers_sem);
650 list_del(&parser->link);
651 up_write(&asymmetric_key_parsers_sem);
653 pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name);
655 EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser);
660 static int __init asymmetric_key_init(void)
662 return register_key_type(&key_type_asymmetric);
665 static void __exit asymmetric_key_cleanup(void)
667 unregister_key_type(&key_type_asymmetric);
670 module_init(asymmetric_key_init);
671 module_exit(asymmetric_key_cleanup);
672 #endif /* !__UBOOT__ */