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 <linux/seq_file.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/ctype.h>
19 #include "asymmetric_keys.h"
21 MODULE_LICENSE("GPL");
23 static LIST_HEAD(asymmetric_key_parsers);
24 static DECLARE_RWSEM(asymmetric_key_parsers_sem);
27 * asymmetric_key_generate_id: Construct an asymmetric key ID
28 * @val_1: First binary blob
29 * @len_1: Length of first binary blob
30 * @val_2: Second binary blob
31 * @len_2: Length of second binary blob
33 * Construct an asymmetric key ID from a pair of binary blobs.
35 struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
40 struct asymmetric_key_id *kid;
42 kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
45 return ERR_PTR(-ENOMEM);
46 kid->len = len_1 + len_2;
47 memcpy(kid->data, val_1, len_1);
48 memcpy(kid->data + len_1, val_2, len_2);
51 EXPORT_SYMBOL_GPL(asymmetric_key_generate_id);
54 * asymmetric_key_id_same - Return true if two asymmetric keys IDs are the same.
55 * @kid_1, @kid_2: The key IDs to compare
57 bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
58 const struct asymmetric_key_id *kid2)
62 if (kid1->len != kid2->len)
64 return memcmp(kid1->data, kid2->data, kid1->len) == 0;
66 EXPORT_SYMBOL_GPL(asymmetric_key_id_same);
69 * asymmetric_match_key_ids - Search asymmetric key IDs
70 * @kids: The list of key IDs to check
71 * @match_id: The key ID we're looking for
73 bool asymmetric_match_key_ids(const struct asymmetric_key_ids *kids,
74 const struct asymmetric_key_id *match_id)
76 if (!kids || !match_id)
78 if (asymmetric_key_id_same(kids->id[0], match_id))
80 if (asymmetric_key_id_same(kids->id[1], match_id))
84 EXPORT_SYMBOL_GPL(asymmetric_match_key_ids);
87 * asymmetric_key_hex_to_key_id - Convert a hex string into a key ID.
88 * @id: The ID as a hex string.
90 struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
92 struct asymmetric_key_id *match_id;
97 return ERR_PTR(-EINVAL);
100 return ERR_PTR(-EINVAL);
102 match_id = kmalloc(sizeof(struct asymmetric_key_id) + hexlen / 2,
105 return ERR_PTR(-ENOMEM);
106 match_id->len = hexlen / 2;
107 ret = hex2bin(match_id->data, id, hexlen / 2);
110 return ERR_PTR(-EINVAL);
116 * Match asymmetric keys by ID.
118 static bool asymmetric_key_cmp(const struct key *key,
119 const struct key_match_data *match_data)
121 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
122 const struct asymmetric_key_id *match_id = match_data->preparsed;
124 return asymmetric_match_key_ids(kids, match_id);
128 * Preparse the match criterion. If we don't set lookup_type and cmp,
129 * the default will be an exact match on the key description.
131 * There are some specifiers for matching key IDs rather than by the key
134 * "id:<id>" - request a key by any available ID
136 * These have to be searched by iteration rather than by direct lookup because
137 * the key is hashed according to its description.
139 static int asymmetric_key_match_preparse(struct key_match_data *match_data)
141 struct asymmetric_key_id *match_id;
142 const char *spec = match_data->raw_data;
147 if (spec[0] == 'i' &&
155 match_id = asymmetric_key_hex_to_key_id(id);
156 if (IS_ERR(match_id))
157 return PTR_ERR(match_id);
159 match_data->preparsed = match_id;
160 match_data->cmp = asymmetric_key_cmp;
161 match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
169 * Free the preparsed the match criterion.
171 static void asymmetric_key_match_free(struct key_match_data *match_data)
173 kfree(match_data->preparsed);
177 * Describe the asymmetric key
179 static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
181 const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
182 const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
183 const struct asymmetric_key_id *kid;
184 const unsigned char *p;
187 seq_puts(m, key->description);
191 subtype->describe(key, m);
193 if (kids && kids->id[0]) {
202 seq_printf(m, "%*phN", n, p);
206 /* put something here to indicate the key's capabilities */
212 * Preparse a asymmetric payload to get format the contents appropriately for the
213 * internal payload to cut down on the number of scans of the data performed.
215 * We also generate a proposed description from the contents of the key that
216 * can be used to name the key if the user doesn't want to provide one.
218 static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
220 struct asymmetric_key_parser *parser;
223 pr_devel("==>%s()\n", __func__);
225 if (prep->datalen == 0)
228 down_read(&asymmetric_key_parsers_sem);
231 list_for_each_entry(parser, &asymmetric_key_parsers, link) {
232 pr_debug("Trying parser '%s'\n", parser->name);
234 ret = parser->parse(prep);
235 if (ret != -EBADMSG) {
236 pr_debug("Parser recognised the format (ret %d)\n",
242 up_read(&asymmetric_key_parsers_sem);
243 pr_devel("<==%s() = %d\n", __func__, ret);
248 * Clean up the preparse data
250 static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
252 struct asymmetric_key_subtype *subtype = prep->type_data[0];
253 struct asymmetric_key_ids *kids = prep->type_data[1];
255 pr_devel("==>%s()\n", __func__);
258 subtype->destroy(prep->payload[0]);
259 module_put(subtype->owner);
266 kfree(prep->description);
270 * dispose of the data dangling from the corpse of a asymmetric key
272 static void asymmetric_key_destroy(struct key *key)
274 struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
275 struct asymmetric_key_ids *kids = key->type_data.p[1];
278 subtype->destroy(key->payload.data);
279 module_put(subtype->owner);
280 key->type_data.p[0] = NULL;
287 key->type_data.p[1] = NULL;
291 struct key_type key_type_asymmetric = {
292 .name = "asymmetric",
293 .preparse = asymmetric_key_preparse,
294 .free_preparse = asymmetric_key_free_preparse,
295 .instantiate = generic_key_instantiate,
296 .match_preparse = asymmetric_key_match_preparse,
297 .match_free = asymmetric_key_match_free,
298 .destroy = asymmetric_key_destroy,
299 .describe = asymmetric_key_describe,
301 EXPORT_SYMBOL_GPL(key_type_asymmetric);
304 * register_asymmetric_key_parser - Register a asymmetric key blob parser
305 * @parser: The parser to register
307 int register_asymmetric_key_parser(struct asymmetric_key_parser *parser)
309 struct asymmetric_key_parser *cursor;
312 down_write(&asymmetric_key_parsers_sem);
314 list_for_each_entry(cursor, &asymmetric_key_parsers, link) {
315 if (strcmp(cursor->name, parser->name) == 0) {
316 pr_err("Asymmetric key parser '%s' already registered\n",
323 list_add_tail(&parser->link, &asymmetric_key_parsers);
325 pr_notice("Asymmetric key parser '%s' registered\n", parser->name);
329 up_write(&asymmetric_key_parsers_sem);
332 EXPORT_SYMBOL_GPL(register_asymmetric_key_parser);
335 * unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser
336 * @parser: The parser to unregister
338 void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser)
340 down_write(&asymmetric_key_parsers_sem);
341 list_del(&parser->link);
342 up_write(&asymmetric_key_parsers_sem);
344 pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name);
346 EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser);
351 static int __init asymmetric_key_init(void)
353 return register_key_type(&key_type_asymmetric);
356 static void __exit asymmetric_key_cleanup(void)
358 unregister_key_type(&key_type_asymmetric);
361 module_init(asymmetric_key_init);
362 module_exit(asymmetric_key_cleanup);