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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> |
2565ca7f | 19 | #include "common.h" |
b56e5a17 | 20 | |
d3bfe841 DH |
21 | static struct key *builtin_trusted_keys; |
22 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING | |
23 | static struct key *secondary_trusted_keys; | |
24 | #endif | |
219a3e86 KS |
25 | #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING |
26 | static struct key *platform_trusted_keys; | |
27 | #endif | |
b56e5a17 DH |
28 | |
29 | extern __initconst const u8 system_certificate_list[]; | |
62226983 | 30 | extern __initconst const unsigned long system_certificate_list_size; |
6cbdfb3d | 31 | extern __initconst const unsigned long module_cert_size; |
b56e5a17 | 32 | |
a511e1af | 33 | /** |
d3bfe841 | 34 | * restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA |
a511e1af DH |
35 | * |
36 | * Restrict the addition of keys into a keyring based on the key-to-be-added | |
d3bfe841 | 37 | * being vouched for by a key in the built in system keyring. |
a511e1af | 38 | */ |
aaf66c88 | 39 | int restrict_link_by_builtin_trusted(struct key *dest_keyring, |
a511e1af | 40 | const struct key_type *type, |
aaf66c88 MM |
41 | const union key_payload *payload, |
42 | struct key *restriction_key) | |
a511e1af | 43 | { |
aaf66c88 MM |
44 | return restrict_link_by_signature(dest_keyring, type, payload, |
45 | builtin_trusted_keys); | |
a511e1af DH |
46 | } |
47 | ||
d3bfe841 DH |
48 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING |
49 | /** | |
50 | * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring | |
51 | * addition by both builtin and secondary keyrings | |
52 | * | |
53 | * Restrict the addition of keys into a keyring based on the key-to-be-added | |
54 | * being vouched for by a key in either the built-in or the secondary system | |
55 | * keyrings. | |
56 | */ | |
57 | int restrict_link_by_builtin_and_secondary_trusted( | |
aaf66c88 | 58 | struct key *dest_keyring, |
d3bfe841 | 59 | const struct key_type *type, |
aaf66c88 MM |
60 | const union key_payload *payload, |
61 | struct key *restrict_key) | |
d3bfe841 DH |
62 | { |
63 | /* If we have a secondary trusted keyring, then that contains a link | |
64 | * through to the builtin keyring and the search will follow that link. | |
65 | */ | |
66 | if (type == &key_type_keyring && | |
aaf66c88 | 67 | dest_keyring == secondary_trusted_keys && |
d3bfe841 DH |
68 | payload == &builtin_trusted_keys->payload) |
69 | /* Allow the builtin keyring to be added to the secondary */ | |
70 | return 0; | |
71 | ||
aaf66c88 MM |
72 | return restrict_link_by_signature(dest_keyring, type, payload, |
73 | secondary_trusted_keys); | |
d3bfe841 | 74 | } |
2b6aa412 MM |
75 | |
76 | /** | |
77 | * Allocate a struct key_restriction for the "builtin and secondary trust" | |
78 | * keyring. Only for use in system_trusted_keyring_init(). | |
79 | */ | |
80 | static __init struct key_restriction *get_builtin_and_secondary_restriction(void) | |
81 | { | |
82 | struct key_restriction *restriction; | |
83 | ||
84 | restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL); | |
85 | ||
86 | if (!restriction) | |
87 | panic("Can't allocate secondary trusted keyring restriction\n"); | |
88 | ||
89 | restriction->check = restrict_link_by_builtin_and_secondary_trusted; | |
90 | ||
91 | return restriction; | |
92 | } | |
d3bfe841 DH |
93 | #endif |
94 | ||
b56e5a17 | 95 | /* |
d3bfe841 | 96 | * Create the trusted keyrings |
b56e5a17 DH |
97 | */ |
98 | static __init int system_trusted_keyring_init(void) | |
99 | { | |
d3bfe841 | 100 | pr_notice("Initialise system trusted keyrings\n"); |
b56e5a17 | 101 | |
d3bfe841 DH |
102 | builtin_trusted_keys = |
103 | keyring_alloc(".builtin_trusted_keys", | |
a6cb0ab7 | 104 | GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), |
028db3e2 LT |
105 | ((KEY_POS_ALL & ~KEY_POS_SETATTR) | |
106 | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH), | |
107 | KEY_ALLOC_NOT_IN_QUOTA, | |
d3bfe841 DH |
108 | NULL, NULL); |
109 | if (IS_ERR(builtin_trusted_keys)) | |
110 | panic("Can't allocate builtin trusted keyring\n"); | |
111 | ||
112 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING | |
113 | secondary_trusted_keys = | |
114 | keyring_alloc(".secondary_trusted_keys", | |
a6cb0ab7 | 115 | GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), |
028db3e2 LT |
116 | ((KEY_POS_ALL & ~KEY_POS_SETATTR) | |
117 | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH | | |
118 | KEY_USR_WRITE), | |
119 | KEY_ALLOC_NOT_IN_QUOTA, | |
2b6aa412 | 120 | get_builtin_and_secondary_restriction(), |
d3bfe841 DH |
121 | NULL); |
122 | if (IS_ERR(secondary_trusted_keys)) | |
123 | panic("Can't allocate secondary trusted keyring\n"); | |
124 | ||
125 | if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0) | |
126 | panic("Can't link trusted keyrings\n"); | |
127 | #endif | |
128 | ||
b56e5a17 DH |
129 | return 0; |
130 | } | |
131 | ||
132 | /* | |
133 | * Must be initialised before we try and load the keys into the keyring. | |
134 | */ | |
135 | device_initcall(system_trusted_keyring_init); | |
136 | ||
6cbdfb3d NJ |
137 | __init int load_module_cert(struct key *keyring) |
138 | { | |
6cbdfb3d NJ |
139 | if (!IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG)) |
140 | return 0; | |
141 | ||
142 | pr_notice("Loading compiled-in module X.509 certificates\n"); | |
143 | ||
e6f0bf09 | 144 | return load_certificate_list(system_certificate_list, module_cert_size, keyring); |
6cbdfb3d NJ |
145 | } |
146 | ||
b56e5a17 DH |
147 | /* |
148 | * Load the compiled-in list of X.509 certificates. | |
149 | */ | |
150 | static __init int load_system_certificate_list(void) | |
151 | { | |
e6f0bf09 | 152 | const u8 *p; |
6cbdfb3d NJ |
153 | unsigned long size; |
154 | ||
b56e5a17 DH |
155 | pr_notice("Loading compiled-in X.509 certificates\n"); |
156 | ||
6cbdfb3d NJ |
157 | #ifdef CONFIG_MODULE_SIG |
158 | p = system_certificate_list; | |
159 | size = system_certificate_list_size; | |
160 | #else | |
161 | p = system_certificate_list + module_cert_size; | |
162 | size = system_certificate_list_size - module_cert_size; | |
163 | #endif | |
164 | ||
e6f0bf09 | 165 | return load_certificate_list(p, size, builtin_trusted_keys); |
b56e5a17 DH |
166 | } |
167 | late_initcall(load_system_certificate_list); | |
091f6e26 DH |
168 | |
169 | #ifdef CONFIG_SYSTEM_DATA_VERIFICATION | |
170 | ||
171 | /** | |
2a7bf671 | 172 | * verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data. |
e68503bd | 173 | * @data: The data to be verified (NULL if expecting internal data). |
091f6e26 | 174 | * @len: Size of @data. |
2a7bf671 | 175 | * @pkcs7: The PKCS#7 message that is the signature. |
d3bfe841 DH |
176 | * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, |
177 | * (void *)1UL for all trusted keys). | |
99db4435 | 178 | * @usage: The use to which the key is being put. |
e68503bd DH |
179 | * @view_content: Callback to gain access to content. |
180 | * @ctx: Context for callback. | |
091f6e26 | 181 | */ |
2a7bf671 TJB |
182 | int verify_pkcs7_message_sig(const void *data, size_t len, |
183 | struct pkcs7_message *pkcs7, | |
184 | struct key *trusted_keys, | |
185 | enum key_being_used_for usage, | |
186 | int (*view_content)(void *ctx, | |
187 | const void *data, size_t len, | |
188 | size_t asn1hdrlen), | |
189 | void *ctx) | |
091f6e26 | 190 | { |
091f6e26 DH |
191 | int ret; |
192 | ||
091f6e26 | 193 | /* The data should be detached - so we need to supply it. */ |
e68503bd | 194 | if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) { |
091f6e26 DH |
195 | pr_err("PKCS#7 signature with non-detached data\n"); |
196 | ret = -EBADMSG; | |
197 | goto error; | |
198 | } | |
199 | ||
99db4435 | 200 | ret = pkcs7_verify(pkcs7, usage); |
091f6e26 DH |
201 | if (ret < 0) |
202 | goto error; | |
203 | ||
d3bfe841 DH |
204 | if (!trusted_keys) { |
205 | trusted_keys = builtin_trusted_keys; | |
817aef26 | 206 | } else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) { |
d3bfe841 DH |
207 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING |
208 | trusted_keys = secondary_trusted_keys; | |
209 | #else | |
210 | trusted_keys = builtin_trusted_keys; | |
211 | #endif | |
278311e4 KS |
212 | } else if (trusted_keys == VERIFY_USE_PLATFORM_KEYRING) { |
213 | #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING | |
214 | trusted_keys = platform_trusted_keys; | |
215 | #else | |
216 | trusted_keys = NULL; | |
217 | #endif | |
218 | if (!trusted_keys) { | |
219 | ret = -ENOKEY; | |
220 | pr_devel("PKCS#7 platform keyring is not available\n"); | |
221 | goto error; | |
222 | } | |
56c58126 ES |
223 | |
224 | ret = is_key_on_revocation_list(pkcs7); | |
225 | if (ret != -ENOKEY) { | |
226 | pr_devel("PKCS#7 platform key is on revocation list\n"); | |
227 | goto error; | |
228 | } | |
d3bfe841 | 229 | } |
bda850cd DH |
230 | ret = pkcs7_validate_trust(pkcs7, trusted_keys); |
231 | if (ret < 0) { | |
232 | if (ret == -ENOKEY) | |
278311e4 | 233 | pr_devel("PKCS#7 signature not signed with a trusted key\n"); |
e68503bd DH |
234 | goto error; |
235 | } | |
236 | ||
237 | if (view_content) { | |
238 | size_t asn1hdrlen; | |
239 | ||
240 | ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen); | |
241 | if (ret < 0) { | |
242 | if (ret == -ENODATA) | |
243 | pr_devel("PKCS#7 message does not contain data\n"); | |
244 | goto error; | |
245 | } | |
246 | ||
247 | ret = view_content(ctx, data, len, asn1hdrlen); | |
091f6e26 DH |
248 | } |
249 | ||
250 | error: | |
2a7bf671 TJB |
251 | pr_devel("<==%s() = %d\n", __func__, ret); |
252 | return ret; | |
253 | } | |
254 | ||
255 | /** | |
256 | * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data. | |
257 | * @data: The data to be verified (NULL if expecting internal data). | |
258 | * @len: Size of @data. | |
259 | * @raw_pkcs7: The PKCS#7 message that is the signature. | |
260 | * @pkcs7_len: The size of @raw_pkcs7. | |
261 | * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, | |
262 | * (void *)1UL for all trusted keys). | |
263 | * @usage: The use to which the key is being put. | |
264 | * @view_content: Callback to gain access to content. | |
265 | * @ctx: Context for callback. | |
266 | */ | |
267 | int verify_pkcs7_signature(const void *data, size_t len, | |
268 | const void *raw_pkcs7, size_t pkcs7_len, | |
269 | struct key *trusted_keys, | |
270 | enum key_being_used_for usage, | |
271 | int (*view_content)(void *ctx, | |
272 | const void *data, size_t len, | |
273 | size_t asn1hdrlen), | |
274 | void *ctx) | |
275 | { | |
276 | struct pkcs7_message *pkcs7; | |
277 | int ret; | |
278 | ||
279 | pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len); | |
280 | if (IS_ERR(pkcs7)) | |
281 | return PTR_ERR(pkcs7); | |
282 | ||
283 | ret = verify_pkcs7_message_sig(data, len, pkcs7, trusted_keys, usage, | |
284 | view_content, ctx); | |
285 | ||
091f6e26 DH |
286 | pkcs7_free_message(pkcs7); |
287 | pr_devel("<==%s() = %d\n", __func__, ret); | |
288 | return ret; | |
289 | } | |
e68503bd | 290 | EXPORT_SYMBOL_GPL(verify_pkcs7_signature); |
091f6e26 DH |
291 | |
292 | #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */ | |
219a3e86 KS |
293 | |
294 | #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING | |
295 | void __init set_platform_trusted_keys(struct key *keyring) | |
296 | { | |
297 | platform_trusted_keys = keyring; | |
298 | } | |
299 | #endif |