blob: 9de610bf1f4b2854e38b8482e16113d0008295f9 [file] [log] [blame]
Thomas Gleixnerb4d0d232019-05-20 19:08:01 +02001// SPDX-License-Identifier: GPL-2.0-or-later
David Howellsb56e5a12013-08-30 16:07:30 +01002/* System trusted keyring for trusted public keys
3 *
4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
David Howellsb56e5a12013-08-30 16:07:30 +01006 */
7
8#include <linux/export.h>
9#include <linux/kernel.h>
10#include <linux/sched.h>
11#include <linux/cred.h>
12#include <linux/err.h>
Mat Martineau2b6aa412016-08-31 16:05:43 -070013#include <linux/slab.h>
Mickaël Salaüna6cb0ab2020-11-20 19:04:25 +010014#include <linux/uidgid.h>
Yannik Sembritzki817aef22018-08-16 14:05:10 +010015#include <linux/verification.h>
David Howellsb56e5a12013-08-30 16:07:30 +010016#include <keys/asymmetric-type.h>
17#include <keys/system_keyring.h>
David Howells091f6e22015-07-20 21:16:28 +010018#include <crypto/pkcs7.h>
David Howellsb56e5a12013-08-30 16:07:30 +010019
David Howellsd3bfe842016-04-06 16:14:27 +010020static struct key *builtin_trusted_keys;
21#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
22static struct key *secondary_trusted_keys;
23#endif
Eric Snowberg56edb6c2022-01-25 21:58:30 -050024#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
25static struct key *machine_trusted_keys;
26#endif
Kairui Song219a3e82019-01-21 17:59:28 +080027#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
28static struct key *platform_trusted_keys;
29#endif
David Howellsb56e5a12013-08-30 16:07:30 +010030
31extern __initconst const u8 system_certificate_list[];
Hendrik Brueckner62226982013-12-05 14:48:22 +010032extern __initconst const unsigned long system_certificate_list_size;
Nayna Jain6cbdfb32021-04-09 10:35:07 -040033extern __initconst const unsigned long module_cert_size;
David Howellsb56e5a12013-08-30 16:07:30 +010034
David Howellsa511e1a2016-04-06 16:14:26 +010035/**
Eric Snowbergef97e7742023-03-02 11:46:48 -050036 * restrict_link_by_builtin_trusted - Restrict keyring addition by built-in CA
37 * @dest_keyring: Keyring being linked to.
38 * @type: The type of key being added.
39 * @payload: The payload of the new key.
40 * @restriction_key: A ring of keys that can be used to vouch for the new cert.
David Howellsa511e1a2016-04-06 16:14:26 +010041 *
42 * Restrict the addition of keys into a keyring based on the key-to-be-added
David Howellsd3bfe842016-04-06 16:14:27 +010043 * being vouched for by a key in the built in system keyring.
David Howellsa511e1a2016-04-06 16:14:26 +010044 */
Mat Martineauaaf66c82016-08-30 11:33:13 -070045int restrict_link_by_builtin_trusted(struct key *dest_keyring,
David Howellsa511e1a2016-04-06 16:14:26 +010046 const struct key_type *type,
Mat Martineauaaf66c82016-08-30 11:33:13 -070047 const union key_payload *payload,
48 struct key *restriction_key)
David Howellsa511e1a2016-04-06 16:14:26 +010049{
Mat Martineauaaf66c82016-08-30 11:33:13 -070050 return restrict_link_by_signature(dest_keyring, type, payload,
51 builtin_trusted_keys);
David Howellsa511e1a2016-04-06 16:14:26 +010052}
53
Eric Snowberg4cfb9082023-05-22 19:09:42 -040054/**
55 * restrict_link_by_digsig_builtin - Restrict digitalSignature key additions by the built-in keyring
56 * @dest_keyring: Keyring being linked to.
57 * @type: The type of key being added.
58 * @payload: The payload of the new key.
59 * @restriction_key: A ring of keys that can be used to vouch for the new cert.
60 *
61 * Restrict the addition of keys into a keyring based on the key-to-be-added
62 * being vouched for by a key in the built in system keyring. The new key
63 * must have the digitalSignature usage field set.
64 */
65int restrict_link_by_digsig_builtin(struct key *dest_keyring,
66 const struct key_type *type,
67 const union key_payload *payload,
68 struct key *restriction_key)
69{
70 return restrict_link_by_digsig(dest_keyring, type, payload,
71 builtin_trusted_keys);
72}
73
David Howellsd3bfe842016-04-06 16:14:27 +010074#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
75/**
76 * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
Eric Snowbergef97e7742023-03-02 11:46:48 -050077 * addition by both built-in and secondary keyrings.
78 * @dest_keyring: Keyring being linked to.
79 * @type: The type of key being added.
80 * @payload: The payload of the new key.
81 * @restrict_key: A ring of keys that can be used to vouch for the new cert.
David Howellsd3bfe842016-04-06 16:14:27 +010082 *
83 * Restrict the addition of keys into a keyring based on the key-to-be-added
84 * being vouched for by a key in either the built-in or the secondary system
85 * keyrings.
86 */
87int restrict_link_by_builtin_and_secondary_trusted(
Mat Martineauaaf66c82016-08-30 11:33:13 -070088 struct key *dest_keyring,
David Howellsd3bfe842016-04-06 16:14:27 +010089 const struct key_type *type,
Mat Martineauaaf66c82016-08-30 11:33:13 -070090 const union key_payload *payload,
91 struct key *restrict_key)
David Howellsd3bfe842016-04-06 16:14:27 +010092{
93 /* If we have a secondary trusted keyring, then that contains a link
94 * through to the builtin keyring and the search will follow that link.
95 */
96 if (type == &key_type_keyring &&
Mat Martineauaaf66c82016-08-30 11:33:13 -070097 dest_keyring == secondary_trusted_keys &&
David Howellsd3bfe842016-04-06 16:14:27 +010098 payload == &builtin_trusted_keys->payload)
99 /* Allow the builtin keyring to be added to the secondary */
100 return 0;
101
Mat Martineauaaf66c82016-08-30 11:33:13 -0700102 return restrict_link_by_signature(dest_keyring, type, payload,
103 secondary_trusted_keys);
David Howellsd3bfe842016-04-06 16:14:27 +0100104}
Mat Martineau2b6aa412016-08-31 16:05:43 -0700105
Eric Snowberg4cfb9082023-05-22 19:09:42 -0400106/**
107 * restrict_link_by_digsig_builtin_and_secondary - Restrict by digitalSignature.
108 * @dest_keyring: Keyring being linked to.
109 * @type: The type of key being added.
110 * @payload: The payload of the new key.
111 * @restrict_key: A ring of keys that can be used to vouch for the new cert.
112 *
113 * Restrict the addition of keys into a keyring based on the key-to-be-added
114 * being vouched for by a key in either the built-in or the secondary system
115 * keyrings. The new key must have the digitalSignature usage field set.
116 */
117int restrict_link_by_digsig_builtin_and_secondary(struct key *dest_keyring,
118 const struct key_type *type,
119 const union key_payload *payload,
120 struct key *restrict_key)
121{
122 /* If we have a secondary trusted keyring, then that contains a link
123 * through to the builtin keyring and the search will follow that link.
124 */
125 if (type == &key_type_keyring &&
126 dest_keyring == secondary_trusted_keys &&
127 payload == &builtin_trusted_keys->payload)
128 /* Allow the builtin keyring to be added to the secondary */
129 return 0;
130
131 return restrict_link_by_digsig(dest_keyring, type, payload,
132 secondary_trusted_keys);
133}
134
Eric Snowbergef97e7742023-03-02 11:46:48 -0500135/*
Mat Martineau2b6aa412016-08-31 16:05:43 -0700136 * Allocate a struct key_restriction for the "builtin and secondary trust"
137 * keyring. Only for use in system_trusted_keyring_init().
138 */
139static __init struct key_restriction *get_builtin_and_secondary_restriction(void)
140{
141 struct key_restriction *restriction;
142
143 restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
144
145 if (!restriction)
146 panic("Can't allocate secondary trusted keyring restriction\n");
147
Eric Snowberg087aa4e2022-01-25 21:58:31 -0500148 if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING))
149 restriction->check = restrict_link_by_builtin_secondary_and_machine;
150 else
151 restriction->check = restrict_link_by_builtin_and_secondary_trusted;
Mat Martineau2b6aa412016-08-31 16:05:43 -0700152
153 return restriction;
154}
Nayna Jain44e69ea2023-08-15 07:27:22 -0400155
156/**
157 * add_to_secondary_keyring - Add to secondary keyring.
158 * @source: Source of key
159 * @data: The blob holding the key
160 * @len: The length of the data blob
161 *
162 * Add a key to the secondary keyring. The key must be vouched for by a key in the builtin,
163 * machine or secondary keyring itself.
164 */
165void __init add_to_secondary_keyring(const char *source, const void *data, size_t len)
166{
167 key_ref_t key;
168 key_perm_t perm;
169
170 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW;
171
172 key = key_create_or_update(make_key_ref(secondary_trusted_keys, 1),
173 "asymmetric",
174 NULL, data, len, perm,
175 KEY_ALLOC_NOT_IN_QUOTA);
176 if (IS_ERR(key)) {
177 pr_err("Problem loading X.509 certificate from %s to secondary keyring %ld\n",
178 source, PTR_ERR(key));
179 return;
180 }
181
182 pr_notice("Loaded X.509 cert '%s'\n", key_ref_to_ptr(key)->description);
183 key_ref_put(key);
184}
David Howellsd3bfe842016-04-06 16:14:27 +0100185#endif
Eric Snowberg56edb6c2022-01-25 21:58:30 -0500186#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
187void __init set_machine_trusted_keys(struct key *keyring)
188{
189 machine_trusted_keys = keyring;
Eric Snowberg087aa4e2022-01-25 21:58:31 -0500190
191 if (key_link(secondary_trusted_keys, machine_trusted_keys) < 0)
192 panic("Can't link (machine) trusted keyrings\n");
193}
194
195/**
196 * restrict_link_by_builtin_secondary_and_machine - Restrict keyring addition.
197 * @dest_keyring: Keyring being linked to.
198 * @type: The type of key being added.
199 * @payload: The payload of the new key.
200 * @restrict_key: A ring of keys that can be used to vouch for the new cert.
201 *
202 * Restrict the addition of keys into a keyring based on the key-to-be-added
203 * being vouched for by a key in either the built-in, the secondary, or
204 * the machine keyrings.
205 */
206int restrict_link_by_builtin_secondary_and_machine(
207 struct key *dest_keyring,
208 const struct key_type *type,
209 const union key_payload *payload,
210 struct key *restrict_key)
211{
212 if (machine_trusted_keys && type == &key_type_keyring &&
213 dest_keyring == secondary_trusted_keys &&
214 payload == &machine_trusted_keys->payload)
215 /* Allow the machine keyring to be added to the secondary */
216 return 0;
217
218 return restrict_link_by_builtin_and_secondary_trusted(dest_keyring, type,
219 payload, restrict_key);
Eric Snowberg56edb6c2022-01-25 21:58:30 -0500220}
221#endif
David Howellsd3bfe842016-04-06 16:14:27 +0100222
David Howellsb56e5a12013-08-30 16:07:30 +0100223/*
David Howellsd3bfe842016-04-06 16:14:27 +0100224 * Create the trusted keyrings
David Howellsb56e5a12013-08-30 16:07:30 +0100225 */
226static __init int system_trusted_keyring_init(void)
227{
David Howellsd3bfe842016-04-06 16:14:27 +0100228 pr_notice("Initialise system trusted keyrings\n");
David Howellsb56e5a12013-08-30 16:07:30 +0100229
David Howellsd3bfe842016-04-06 16:14:27 +0100230 builtin_trusted_keys =
231 keyring_alloc(".builtin_trusted_keys",
Mickaël Salaüna6cb0ab2020-11-20 19:04:25 +0100232 GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
Linus Torvalds028db3e2019-07-10 18:43:43 -0700233 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
234 KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
235 KEY_ALLOC_NOT_IN_QUOTA,
David Howellsd3bfe842016-04-06 16:14:27 +0100236 NULL, NULL);
237 if (IS_ERR(builtin_trusted_keys))
238 panic("Can't allocate builtin trusted keyring\n");
239
240#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
241 secondary_trusted_keys =
242 keyring_alloc(".secondary_trusted_keys",
Mickaël Salaüna6cb0ab2020-11-20 19:04:25 +0100243 GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
Linus Torvalds028db3e2019-07-10 18:43:43 -0700244 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
245 KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH |
246 KEY_USR_WRITE),
247 KEY_ALLOC_NOT_IN_QUOTA,
Mat Martineau2b6aa412016-08-31 16:05:43 -0700248 get_builtin_and_secondary_restriction(),
David Howellsd3bfe842016-04-06 16:14:27 +0100249 NULL);
250 if (IS_ERR(secondary_trusted_keys))
251 panic("Can't allocate secondary trusted keyring\n");
252
253 if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
254 panic("Can't link trusted keyrings\n");
255#endif
256
David Howellsb56e5a12013-08-30 16:07:30 +0100257 return 0;
258}
259
260/*
261 * Must be initialised before we try and load the keys into the keyring.
262 */
263device_initcall(system_trusted_keyring_init);
264
Nayna Jain6cbdfb32021-04-09 10:35:07 -0400265__init int load_module_cert(struct key *keyring)
266{
Nayna Jain6cbdfb32021-04-09 10:35:07 -0400267 if (!IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG))
268 return 0;
269
270 pr_notice("Loading compiled-in module X.509 certificates\n");
271
David Howells60050ff2022-05-18 23:48:09 +0100272 return x509_load_certificate_list(system_certificate_list,
273 module_cert_size, keyring);
Nayna Jain6cbdfb32021-04-09 10:35:07 -0400274}
275
David Howellsb56e5a12013-08-30 16:07:30 +0100276/*
277 * Load the compiled-in list of X.509 certificates.
278 */
279static __init int load_system_certificate_list(void)
280{
Linus Torvaldse6f0bf02021-05-01 15:32:18 -0700281 const u8 *p;
Nayna Jain6cbdfb32021-04-09 10:35:07 -0400282 unsigned long size;
283
David Howellsb56e5a12013-08-30 16:07:30 +0100284 pr_notice("Loading compiled-in X.509 certificates\n");
285
Nayna Jain6cbdfb32021-04-09 10:35:07 -0400286#ifdef CONFIG_MODULE_SIG
287 p = system_certificate_list;
288 size = system_certificate_list_size;
289#else
290 p = system_certificate_list + module_cert_size;
291 size = system_certificate_list_size - module_cert_size;
292#endif
293
David Howells60050ff2022-05-18 23:48:09 +0100294 return x509_load_certificate_list(p, size, builtin_trusted_keys);
David Howellsb56e5a12013-08-30 16:07:30 +0100295}
296late_initcall(load_system_certificate_list);
David Howells091f6e22015-07-20 21:16:28 +0100297
298#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
299
300/**
Thiago Jung Bauermann2a7bf672019-06-27 23:19:25 -0300301 * verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data.
David Howellse68503b2016-04-06 16:14:24 +0100302 * @data: The data to be verified (NULL if expecting internal data).
David Howells091f6e22015-07-20 21:16:28 +0100303 * @len: Size of @data.
Thiago Jung Bauermann2a7bf672019-06-27 23:19:25 -0300304 * @pkcs7: The PKCS#7 message that is the signature.
David Howellsd3bfe842016-04-06 16:14:27 +0100305 * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
306 * (void *)1UL for all trusted keys).
David Howells99db4432015-08-05 15:22:27 +0100307 * @usage: The use to which the key is being put.
David Howellse68503b2016-04-06 16:14:24 +0100308 * @view_content: Callback to gain access to content.
309 * @ctx: Context for callback.
David Howells091f6e22015-07-20 21:16:28 +0100310 */
Thiago Jung Bauermann2a7bf672019-06-27 23:19:25 -0300311int verify_pkcs7_message_sig(const void *data, size_t len,
312 struct pkcs7_message *pkcs7,
313 struct key *trusted_keys,
314 enum key_being_used_for usage,
315 int (*view_content)(void *ctx,
316 const void *data, size_t len,
317 size_t asn1hdrlen),
318 void *ctx)
David Howells091f6e22015-07-20 21:16:28 +0100319{
David Howells091f6e22015-07-20 21:16:28 +0100320 int ret;
321
David Howells091f6e22015-07-20 21:16:28 +0100322 /* The data should be detached - so we need to supply it. */
David Howellse68503b2016-04-06 16:14:24 +0100323 if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
David Howells091f6e22015-07-20 21:16:28 +0100324 pr_err("PKCS#7 signature with non-detached data\n");
325 ret = -EBADMSG;
326 goto error;
327 }
328
David Howells99db4432015-08-05 15:22:27 +0100329 ret = pkcs7_verify(pkcs7, usage);
David Howells091f6e22015-07-20 21:16:28 +0100330 if (ret < 0)
331 goto error;
332
Eric Snowberg218a2682023-08-17 10:04:07 -0400333 ret = is_key_on_revocation_list(pkcs7);
334 if (ret != -ENOKEY) {
335 pr_devel("PKCS#7 key is on revocation list\n");
336 goto error;
337 }
338
David Howellsd3bfe842016-04-06 16:14:27 +0100339 if (!trusted_keys) {
340 trusted_keys = builtin_trusted_keys;
Yannik Sembritzki817aef22018-08-16 14:05:10 +0100341 } else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {
David Howellsd3bfe842016-04-06 16:14:27 +0100342#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
343 trusted_keys = secondary_trusted_keys;
344#else
345 trusted_keys = builtin_trusted_keys;
346#endif
Kairui Song278311e2019-01-21 17:59:29 +0800347 } else if (trusted_keys == VERIFY_USE_PLATFORM_KEYRING) {
348#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
349 trusted_keys = platform_trusted_keys;
350#else
351 trusted_keys = NULL;
352#endif
353 if (!trusted_keys) {
354 ret = -ENOKEY;
355 pr_devel("PKCS#7 platform keyring is not available\n");
356 goto error;
357 }
David Howellsd3bfe842016-04-06 16:14:27 +0100358 }
David Howellsbda850c2016-04-06 16:14:24 +0100359 ret = pkcs7_validate_trust(pkcs7, trusted_keys);
360 if (ret < 0) {
361 if (ret == -ENOKEY)
Kairui Song278311e2019-01-21 17:59:29 +0800362 pr_devel("PKCS#7 signature not signed with a trusted key\n");
David Howellse68503b2016-04-06 16:14:24 +0100363 goto error;
364 }
365
366 if (view_content) {
367 size_t asn1hdrlen;
368
369 ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
370 if (ret < 0) {
371 if (ret == -ENODATA)
372 pr_devel("PKCS#7 message does not contain data\n");
373 goto error;
374 }
375
376 ret = view_content(ctx, data, len, asn1hdrlen);
David Howells091f6e22015-07-20 21:16:28 +0100377 }
378
379error:
Thiago Jung Bauermann2a7bf672019-06-27 23:19:25 -0300380 pr_devel("<==%s() = %d\n", __func__, ret);
381 return ret;
382}
383
384/**
385 * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
386 * @data: The data to be verified (NULL if expecting internal data).
387 * @len: Size of @data.
388 * @raw_pkcs7: The PKCS#7 message that is the signature.
389 * @pkcs7_len: The size of @raw_pkcs7.
390 * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
391 * (void *)1UL for all trusted keys).
392 * @usage: The use to which the key is being put.
393 * @view_content: Callback to gain access to content.
394 * @ctx: Context for callback.
395 */
396int verify_pkcs7_signature(const void *data, size_t len,
397 const void *raw_pkcs7, size_t pkcs7_len,
398 struct key *trusted_keys,
399 enum key_being_used_for usage,
400 int (*view_content)(void *ctx,
401 const void *data, size_t len,
402 size_t asn1hdrlen),
403 void *ctx)
404{
405 struct pkcs7_message *pkcs7;
406 int ret;
407
408 pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
409 if (IS_ERR(pkcs7))
410 return PTR_ERR(pkcs7);
411
412 ret = verify_pkcs7_message_sig(data, len, pkcs7, trusted_keys, usage,
413 view_content, ctx);
414
David Howells091f6e22015-07-20 21:16:28 +0100415 pkcs7_free_message(pkcs7);
416 pr_devel("<==%s() = %d\n", __func__, ret);
417 return ret;
418}
David Howellse68503b2016-04-06 16:14:24 +0100419EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
David Howells091f6e22015-07-20 21:16:28 +0100420
421#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
Kairui Song219a3e82019-01-21 17:59:28 +0800422
423#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
424void __init set_platform_trusted_keys(struct key *keyring)
425{
426 platform_trusted_keys = keyring;
427}
428#endif