Commit | Line | Data |
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b4d0d230 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
b56e5a17 DH |
2 | /* 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) | |
b56e5a17 DH |
6 | */ |
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> | |
2b6aa412 | 13 | #include <linux/slab.h> |
a6cb0ab7 | 14 | #include <linux/uidgid.h> |
817aef26 | 15 | #include <linux/verification.h> |
b56e5a17 DH |
16 | #include <keys/asymmetric-type.h> |
17 | #include <keys/system_keyring.h> | |
091f6e26 | 18 | #include <crypto/pkcs7.h> |
b56e5a17 | 19 | |
d3bfe841 DH |
20 | static struct key *builtin_trusted_keys; |
21 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING | |
22 | static struct key *secondary_trusted_keys; | |
23 | #endif | |
56edb6c2 ES |
24 | #ifdef CONFIG_INTEGRITY_MACHINE_KEYRING |
25 | static struct key *machine_trusted_keys; | |
26 | #endif | |
219a3e86 KS |
27 | #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING |
28 | static struct key *platform_trusted_keys; | |
29 | #endif | |
b56e5a17 DH |
30 | |
31 | extern __initconst const u8 system_certificate_list[]; | |
62226983 | 32 | extern __initconst const unsigned long system_certificate_list_size; |
6cbdfb3d | 33 | extern __initconst const unsigned long module_cert_size; |
b56e5a17 | 34 | |
a511e1af | 35 | /** |
ef97e774 ES |
36 | * 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. | |
a511e1af DH |
41 | * |
42 | * Restrict the addition of keys into a keyring based on the key-to-be-added | |
d3bfe841 | 43 | * being vouched for by a key in the built in system keyring. |
a511e1af | 44 | */ |
aaf66c88 | 45 | int restrict_link_by_builtin_trusted(struct key *dest_keyring, |
a511e1af | 46 | const struct key_type *type, |
aaf66c88 MM |
47 | const union key_payload *payload, |
48 | struct key *restriction_key) | |
a511e1af | 49 | { |
aaf66c88 MM |
50 | return restrict_link_by_signature(dest_keyring, type, payload, |
51 | builtin_trusted_keys); | |
a511e1af DH |
52 | } |
53 | ||
4cfb9080 ES |
54 | /** |
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 | */ | |
65 | int 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 | ||
d3bfe841 DH |
74 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING |
75 | /** | |
76 | * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring | |
ef97e774 ES |
77 | * 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. | |
d3bfe841 DH |
82 | * |
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 | */ | |
87 | int restrict_link_by_builtin_and_secondary_trusted( | |
aaf66c88 | 88 | struct key *dest_keyring, |
d3bfe841 | 89 | const struct key_type *type, |
aaf66c88 MM |
90 | const union key_payload *payload, |
91 | struct key *restrict_key) | |
d3bfe841 DH |
92 | { |
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 && | |
aaf66c88 | 97 | dest_keyring == secondary_trusted_keys && |
d3bfe841 DH |
98 | payload == &builtin_trusted_keys->payload) |
99 | /* Allow the builtin keyring to be added to the secondary */ | |
100 | return 0; | |
101 | ||
aaf66c88 MM |
102 | return restrict_link_by_signature(dest_keyring, type, payload, |
103 | secondary_trusted_keys); | |
d3bfe841 | 104 | } |
2b6aa412 | 105 | |
4cfb9080 ES |
106 | /** |
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 | */ | |
117 | int 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 | ||
ef97e774 | 135 | /* |
2b6aa412 MM |
136 | * Allocate a struct key_restriction for the "builtin and secondary trust" |
137 | * keyring. Only for use in system_trusted_keyring_init(). | |
138 | */ | |
139 | static __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 | ||
087aa4ed ES |
148 | 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; | |
2b6aa412 MM |
152 | |
153 | return restriction; | |
154 | } | |
44e69ea5 NJ |
155 | |
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 | */ | |
165 | void __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 | } | |
d3bfe841 | 185 | #endif |
56edb6c2 ES |
186 | #ifdef CONFIG_INTEGRITY_MACHINE_KEYRING |
187 | void __init set_machine_trusted_keys(struct key *keyring) | |
188 | { | |
189 | machine_trusted_keys = keyring; | |
087aa4ed ES |
190 | |
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 | */ | |
206 | int 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); | |
56edb6c2 ES |
220 | } |
221 | #endif | |
d3bfe841 | 222 | |
b56e5a17 | 223 | /* |
d3bfe841 | 224 | * Create the trusted keyrings |
b56e5a17 DH |
225 | */ |
226 | static __init int system_trusted_keyring_init(void) | |
227 | { | |
d3bfe841 | 228 | pr_notice("Initialise system trusted keyrings\n"); |
b56e5a17 | 229 | |
d3bfe841 DH |
230 | builtin_trusted_keys = |
231 | keyring_alloc(".builtin_trusted_keys", | |
a6cb0ab7 | 232 | GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), |
028db3e2 LT |
233 | ((KEY_POS_ALL & ~KEY_POS_SETATTR) | |
234 | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH), | |
235 | KEY_ALLOC_NOT_IN_QUOTA, | |
d3bfe841 DH |
236 | 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", | |
a6cb0ab7 | 243 | GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), |
028db3e2 LT |
244 | ((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, | |
2b6aa412 | 248 | get_builtin_and_secondary_restriction(), |
d3bfe841 DH |
249 | 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 | ||
b56e5a17 DH |
257 | return 0; |
258 | } | |
259 | ||
260 | /* | |
261 | * Must be initialised before we try and load the keys into the keyring. | |
262 | */ | |
263 | device_initcall(system_trusted_keyring_init); | |
264 | ||
6cbdfb3d NJ |
265 | __init int load_module_cert(struct key *keyring) |
266 | { | |
6cbdfb3d NJ |
267 | if (!IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG)) |
268 | return 0; | |
269 | ||
270 | pr_notice("Loading compiled-in module X.509 certificates\n"); | |
271 | ||
60050ffe DH |
272 | return x509_load_certificate_list(system_certificate_list, |
273 | module_cert_size, keyring); | |
6cbdfb3d NJ |
274 | } |
275 | ||
b56e5a17 DH |
276 | /* |
277 | * Load the compiled-in list of X.509 certificates. | |
278 | */ | |
279 | static __init int load_system_certificate_list(void) | |
280 | { | |
e6f0bf09 | 281 | const u8 *p; |
6cbdfb3d NJ |
282 | unsigned long size; |
283 | ||
b56e5a17 DH |
284 | pr_notice("Loading compiled-in X.509 certificates\n"); |
285 | ||
6cbdfb3d NJ |
286 | #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 | ||
60050ffe | 294 | return x509_load_certificate_list(p, size, builtin_trusted_keys); |
b56e5a17 DH |
295 | } |
296 | late_initcall(load_system_certificate_list); | |
091f6e26 DH |
297 | |
298 | #ifdef CONFIG_SYSTEM_DATA_VERIFICATION | |
299 | ||
300 | /** | |
2a7bf671 | 301 | * verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data. |
e68503bd | 302 | * @data: The data to be verified (NULL if expecting internal data). |
091f6e26 | 303 | * @len: Size of @data. |
2a7bf671 | 304 | * @pkcs7: The PKCS#7 message that is the signature. |
d3bfe841 DH |
305 | * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, |
306 | * (void *)1UL for all trusted keys). | |
99db4435 | 307 | * @usage: The use to which the key is being put. |
e68503bd DH |
308 | * @view_content: Callback to gain access to content. |
309 | * @ctx: Context for callback. | |
091f6e26 | 310 | */ |
2a7bf671 TJB |
311 | int 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) | |
091f6e26 | 319 | { |
091f6e26 DH |
320 | int ret; |
321 | ||
091f6e26 | 322 | /* The data should be detached - so we need to supply it. */ |
e68503bd | 323 | if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) { |
091f6e26 DH |
324 | pr_err("PKCS#7 signature with non-detached data\n"); |
325 | ret = -EBADMSG; | |
326 | goto error; | |
327 | } | |
328 | ||
99db4435 | 329 | ret = pkcs7_verify(pkcs7, usage); |
091f6e26 DH |
330 | if (ret < 0) |
331 | goto error; | |
332 | ||
218a2680 ES |
333 | 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 | ||
d3bfe841 DH |
339 | if (!trusted_keys) { |
340 | trusted_keys = builtin_trusted_keys; | |
817aef26 | 341 | } else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) { |
d3bfe841 DH |
342 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING |
343 | trusted_keys = secondary_trusted_keys; | |
344 | #else | |
345 | trusted_keys = builtin_trusted_keys; | |
346 | #endif | |
278311e4 KS |
347 | } 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 | } | |
d3bfe841 | 358 | } |
bda850cd DH |
359 | ret = pkcs7_validate_trust(pkcs7, trusted_keys); |
360 | if (ret < 0) { | |
361 | if (ret == -ENOKEY) | |
278311e4 | 362 | pr_devel("PKCS#7 signature not signed with a trusted key\n"); |
e68503bd DH |
363 | 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); | |
091f6e26 DH |
377 | } |
378 | ||
379 | error: | |
2a7bf671 TJB |
380 | 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 | */ | |
396 | int 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 | ||
091f6e26 DH |
415 | pkcs7_free_message(pkcs7); |
416 | pr_devel("<==%s() = %d\n", __func__, ret); | |
417 | return ret; | |
418 | } | |
e68503bd | 419 | EXPORT_SYMBOL_GPL(verify_pkcs7_signature); |
091f6e26 DH |
420 | |
421 | #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */ | |
219a3e86 KS |
422 | |
423 | #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING | |
424 | void __init set_platform_trusted_keys(struct key *keyring) | |
425 | { | |
426 | platform_trusted_keys = keyring; | |
427 | } | |
428 | #endif |