1 /* Asymmetric public-key cryptography key type
3 * See Documentation/security/asymmetric-keys.txt
5 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
6 * Written by David Howells (dhowells@redhat.com)
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public Licence
10 * as published by the Free Software Foundation; either version
11 * 2 of the Licence, or (at your option) any later version.
13 #include <keys/asymmetric-subtype.h>
14 #include <keys/asymmetric-parser.h>
15 #include <crypto/public_key.h>
16 #include <linux/seq_file.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/ctype.h>
20 #include "asymmetric_keys.h"
22 MODULE_LICENSE("GPL");
24 const char *const key_being_used_for[NR__KEY_BEING_USED_FOR] = {
25 [VERIFYING_MODULE_SIGNATURE] = "mod sig",
26 [VERIFYING_FIRMWARE_SIGNATURE] = "firmware sig",
27 [VERIFYING_KEXEC_PE_SIGNATURE] = "kexec PE sig",
28 [VERIFYING_KEY_SIGNATURE] = "key sig",
29 [VERIFYING_KEY_SELF_SIGNATURE] = "key self sig",
30 [VERIFYING_UNSPECIFIED_SIGNATURE] = "unspec sig",
32 EXPORT_SYMBOL_GPL(key_being_used_for);
34 static LIST_HEAD(asymmetric_key_parsers);
35 static DECLARE_RWSEM(asymmetric_key_parsers_sem);
38 * asymmetric_key_generate_id: Construct an asymmetric key ID
39 * @val_1: First binary blob
40 * @len_1: Length of first binary blob
41 * @val_2: Second binary blob
42 * @len_2: Length of second binary blob
44 * Construct an asymmetric key ID from a pair of binary blobs.
46 struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
51 struct asymmetric_key_id *kid;
53 kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
56 return ERR_PTR(-ENOMEM);
57 kid->len = len_1 + len_2;
58 memcpy(kid->data, val_1, len_1);
59 memcpy(kid->data + len_1, val_2, len_2);
62 EXPORT_SYMBOL_GPL(asymmetric_key_generate_id);
65 * asymmetric_key_id_same - Return true if two asymmetric keys IDs are the same.
66 * @kid_1, @kid_2: The key IDs to compare
68 bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
69 const struct asymmetric_key_id *kid2)
73 if (kid1->len != kid2->len)
75 return memcmp(kid1->data, kid2->data, kid1->len) == 0;
77 EXPORT_SYMBOL_GPL(asymmetric_key_id_same);
80 * asymmetric_key_id_partial - Return true if two asymmetric keys IDs
82 * @kid_1, @kid_2: The key IDs to compare
84 bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
85 const struct asymmetric_key_id *kid2)
89 if (kid1->len < kid2->len)
91 return memcmp(kid1->data + (kid1->len - kid2->len),
92 kid2->data, kid2->len) == 0;
94 EXPORT_SYMBOL_GPL(asymmetric_key_id_partial);
97 * asymmetric_match_key_ids - Search asymmetric key IDs
98 * @kids: The list of key IDs to check
99 * @match_id: The key ID we're looking for
100 * @match: The match function to use
102 static bool asymmetric_match_key_ids(
103 const struct asymmetric_key_ids *kids,
104 const struct asymmetric_key_id *match_id,
105 bool (*match)(const struct asymmetric_key_id *kid1,
106 const struct asymmetric_key_id *kid2))
110 if (!kids || !match_id)
112 for (i = 0; i < ARRAY_SIZE(kids->id); i++)
113 if (match(kids->id[i], match_id))
118 /* helper function can be called directly with pre-allocated memory */
119 inline int __asymmetric_key_hex_to_key_id(const char *id,
120 struct asymmetric_key_id *match_id,
123 match_id->len = hexlen;
124 return hex2bin(match_id->data, id, hexlen);
128 * asymmetric_key_hex_to_key_id - Convert a hex string into a key ID.
129 * @id: The ID as a hex string.
131 struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
133 struct asymmetric_key_id *match_id;
138 return ERR_PTR(-EINVAL);
139 asciihexlen = strlen(id);
141 return ERR_PTR(-EINVAL);
143 match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2,
146 return ERR_PTR(-ENOMEM);
147 ret = __asymmetric_key_hex_to_key_id(id, match_id, asciihexlen / 2);
150 return ERR_PTR(-EINVAL);
156 * Match asymmetric keys by an exact match on an ID.
158 static bool asymmetric_key_cmp(const struct key *key,
159 const struct key_match_data *match_data)
161 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
162 const struct asymmetric_key_id *match_id = match_data->preparsed;
164 return asymmetric_match_key_ids(kids, match_id,
165 asymmetric_key_id_same);
169 * Match asymmetric keys by a partial match on an IDs.
171 static bool asymmetric_key_cmp_partial(const struct key *key,
172 const struct key_match_data *match_data)
174 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
175 const struct asymmetric_key_id *match_id = match_data->preparsed;
177 return asymmetric_match_key_ids(kids, match_id,
178 asymmetric_key_id_partial);
182 * Preparse the match criterion. If we don't set lookup_type and cmp,
183 * the default will be an exact match on the key description.
185 * There are some specifiers for matching key IDs rather than by the key
188 * "id:<id>" - find a key by partial match on any available ID
189 * "ex:<id>" - find a key by exact match on any available ID
191 * These have to be searched by iteration rather than by direct lookup because
192 * the key is hashed according to its description.
194 static int asymmetric_key_match_preparse(struct key_match_data *match_data)
196 struct asymmetric_key_id *match_id;
197 const char *spec = match_data->raw_data;
199 bool (*cmp)(const struct key *, const struct key_match_data *) =
204 if (spec[0] == 'i' &&
208 cmp = asymmetric_key_cmp_partial;
209 } else if (spec[0] == 'e' &&
217 match_id = asymmetric_key_hex_to_key_id(id);
218 if (IS_ERR(match_id))
219 return PTR_ERR(match_id);
221 match_data->preparsed = match_id;
222 match_data->cmp = cmp;
223 match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
231 * Free the preparsed the match criterion.
233 static void asymmetric_key_match_free(struct key_match_data *match_data)
235 kfree(match_data->preparsed);
239 * Describe the asymmetric key
241 static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
243 const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
244 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
245 const struct asymmetric_key_id *kid;
246 const unsigned char *p;
249 seq_puts(m, key->description);
253 subtype->describe(key, m);
255 if (kids && kids->id[1]) {
264 seq_printf(m, "%*phN", n, p);
268 /* put something here to indicate the key's capabilities */
274 * Preparse a asymmetric payload to get format the contents appropriately for the
275 * internal payload to cut down on the number of scans of the data performed.
277 * We also generate a proposed description from the contents of the key that
278 * can be used to name the key if the user doesn't want to provide one.
280 static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
282 struct asymmetric_key_parser *parser;
285 pr_devel("==>%s()\n", __func__);
287 if (prep->datalen == 0)
290 down_read(&asymmetric_key_parsers_sem);
293 list_for_each_entry(parser, &asymmetric_key_parsers, link) {
294 pr_debug("Trying parser '%s'\n", parser->name);
296 ret = parser->parse(prep);
297 if (ret != -EBADMSG) {
298 pr_debug("Parser recognised the format (ret %d)\n",
304 up_read(&asymmetric_key_parsers_sem);
305 pr_devel("<==%s() = %d\n", __func__, ret);
310 * Clean up the key ID list
312 static void asymmetric_key_free_kids(struct asymmetric_key_ids *kids)
317 for (i = 0; i < ARRAY_SIZE(kids->id); i++)
324 * Clean up the preparse data
326 static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
328 struct asymmetric_key_subtype *subtype = prep->payload.data[asym_subtype];
329 struct asymmetric_key_ids *kids = prep->payload.data[asym_key_ids];
331 pr_devel("==>%s()\n", __func__);
334 subtype->destroy(prep->payload.data[asym_crypto]);
335 module_put(subtype->owner);
337 asymmetric_key_free_kids(kids);
338 kfree(prep->description);
342 * dispose of the data dangling from the corpse of a asymmetric key
344 static void asymmetric_key_destroy(struct key *key)
346 struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
347 struct asymmetric_key_ids *kids = key->payload.data[asym_key_ids];
348 void *data = key->payload.data[asym_crypto];
350 key->payload.data[asym_crypto] = NULL;
351 key->payload.data[asym_subtype] = NULL;
352 key->payload.data[asym_key_ids] = NULL;
355 subtype->destroy(data);
356 module_put(subtype->owner);
359 asymmetric_key_free_kids(kids);
362 struct key_type key_type_asymmetric = {
363 .name = "asymmetric",
364 .preparse = asymmetric_key_preparse,
365 .free_preparse = asymmetric_key_free_preparse,
366 .instantiate = generic_key_instantiate,
367 .match_preparse = asymmetric_key_match_preparse,
368 .match_free = asymmetric_key_match_free,
369 .destroy = asymmetric_key_destroy,
370 .describe = asymmetric_key_describe,
372 EXPORT_SYMBOL_GPL(key_type_asymmetric);
375 * register_asymmetric_key_parser - Register a asymmetric key blob parser
376 * @parser: The parser to register
378 int register_asymmetric_key_parser(struct asymmetric_key_parser *parser)
380 struct asymmetric_key_parser *cursor;
383 down_write(&asymmetric_key_parsers_sem);
385 list_for_each_entry(cursor, &asymmetric_key_parsers, link) {
386 if (strcmp(cursor->name, parser->name) == 0) {
387 pr_err("Asymmetric key parser '%s' already registered\n",
394 list_add_tail(&parser->link, &asymmetric_key_parsers);
396 pr_notice("Asymmetric key parser '%s' registered\n", parser->name);
400 up_write(&asymmetric_key_parsers_sem);
403 EXPORT_SYMBOL_GPL(register_asymmetric_key_parser);
406 * unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser
407 * @parser: The parser to unregister
409 void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser)
411 down_write(&asymmetric_key_parsers_sem);
412 list_del(&parser->link);
413 up_write(&asymmetric_key_parsers_sem);
415 pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name);
417 EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser);
422 static int __init asymmetric_key_init(void)
424 return register_key_type(&key_type_asymmetric);
427 static void __exit asymmetric_key_cleanup(void)
429 unregister_key_type(&key_type_asymmetric);
432 module_init(asymmetric_key_init);
433 module_exit(asymmetric_key_cleanup);