1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* System trusted keyring for trusted public keys
4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
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>
13 #include <linux/slab.h>
14 #include <linux/uidgid.h>
15 #include <linux/verification.h>
16 #include <keys/asymmetric-type.h>
17 #include <keys/system_keyring.h>
18 #include <crypto/pkcs7.h>
20 static struct key
*builtin_trusted_keys
;
21 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
22 static struct key
*secondary_trusted_keys
;
24 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
25 static struct key
*platform_trusted_keys
;
28 extern __initconst
const u8 system_certificate_list
[];
29 extern __initconst
const unsigned long system_certificate_list_size
;
32 * restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
34 * Restrict the addition of keys into a keyring based on the key-to-be-added
35 * being vouched for by a key in the built in system keyring.
37 int restrict_link_by_builtin_trusted(struct key
*dest_keyring
,
38 const struct key_type
*type
,
39 const union key_payload
*payload
,
40 struct key
*restriction_key
)
42 return restrict_link_by_signature(dest_keyring
, type
, payload
,
43 builtin_trusted_keys
);
46 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
48 * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
49 * addition by both builtin and secondary keyrings
51 * Restrict the addition of keys into a keyring based on the key-to-be-added
52 * being vouched for by a key in either the built-in or the secondary system
55 int restrict_link_by_builtin_and_secondary_trusted(
56 struct key
*dest_keyring
,
57 const struct key_type
*type
,
58 const union key_payload
*payload
,
59 struct key
*restrict_key
)
61 /* If we have a secondary trusted keyring, then that contains a link
62 * through to the builtin keyring and the search will follow that link.
64 if (type
== &key_type_keyring
&&
65 dest_keyring
== secondary_trusted_keys
&&
66 payload
== &builtin_trusted_keys
->payload
)
67 /* Allow the builtin keyring to be added to the secondary */
70 return restrict_link_by_signature(dest_keyring
, type
, payload
,
71 secondary_trusted_keys
);
75 * Allocate a struct key_restriction for the "builtin and secondary trust"
76 * keyring. Only for use in system_trusted_keyring_init().
78 static __init
struct key_restriction
*get_builtin_and_secondary_restriction(void)
80 struct key_restriction
*restriction
;
82 restriction
= kzalloc(sizeof(struct key_restriction
), GFP_KERNEL
);
85 panic("Can't allocate secondary trusted keyring restriction\n");
87 restriction
->check
= restrict_link_by_builtin_and_secondary_trusted
;
94 * Create the trusted keyrings
96 static __init
int system_trusted_keyring_init(void)
98 pr_notice("Initialise system trusted keyrings\n");
100 builtin_trusted_keys
=
101 keyring_alloc(".builtin_trusted_keys",
102 GLOBAL_ROOT_UID
, GLOBAL_ROOT_GID
, current_cred(),
103 ((KEY_POS_ALL
& ~KEY_POS_SETATTR
) |
104 KEY_USR_VIEW
| KEY_USR_READ
| KEY_USR_SEARCH
),
105 KEY_ALLOC_NOT_IN_QUOTA
,
107 if (IS_ERR(builtin_trusted_keys
))
108 panic("Can't allocate builtin trusted keyring\n");
110 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
111 secondary_trusted_keys
=
112 keyring_alloc(".secondary_trusted_keys",
113 GLOBAL_ROOT_UID
, GLOBAL_ROOT_GID
, current_cred(),
114 ((KEY_POS_ALL
& ~KEY_POS_SETATTR
) |
115 KEY_USR_VIEW
| KEY_USR_READ
| KEY_USR_SEARCH
|
117 KEY_ALLOC_NOT_IN_QUOTA
,
118 get_builtin_and_secondary_restriction(),
120 if (IS_ERR(secondary_trusted_keys
))
121 panic("Can't allocate secondary trusted keyring\n");
123 if (key_link(secondary_trusted_keys
, builtin_trusted_keys
) < 0)
124 panic("Can't link trusted keyrings\n");
131 * Must be initialised before we try and load the keys into the keyring.
133 device_initcall(system_trusted_keyring_init
);
136 * Load the compiled-in list of X.509 certificates.
138 static __init
int load_system_certificate_list(void)
144 pr_notice("Loading compiled-in X.509 certificates\n");
146 p
= system_certificate_list
;
147 end
= p
+ system_certificate_list_size
;
149 /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
150 * than 256 bytes in size.
157 plen
= (p
[2] << 8) | p
[3];
162 key
= key_create_or_update(make_key_ref(builtin_trusted_keys
, 1),
167 ((KEY_POS_ALL
& ~KEY_POS_SETATTR
) |
168 KEY_USR_VIEW
| KEY_USR_READ
),
169 KEY_ALLOC_NOT_IN_QUOTA
|
171 KEY_ALLOC_BYPASS_RESTRICTION
);
173 pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
176 pr_notice("Loaded X.509 cert '%s'\n",
177 key_ref_to_ptr(key
)->description
);
186 pr_err("Problem parsing in-kernel X.509 certificate list\n");
189 late_initcall(load_system_certificate_list
);
191 #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
194 * verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data.
195 * @data: The data to be verified (NULL if expecting internal data).
196 * @len: Size of @data.
197 * @pkcs7: The PKCS#7 message that is the signature.
198 * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
199 * (void *)1UL for all trusted keys).
200 * @usage: The use to which the key is being put.
201 * @view_content: Callback to gain access to content.
202 * @ctx: Context for callback.
204 int verify_pkcs7_message_sig(const void *data
, size_t len
,
205 struct pkcs7_message
*pkcs7
,
206 struct key
*trusted_keys
,
207 enum key_being_used_for usage
,
208 int (*view_content
)(void *ctx
,
209 const void *data
, size_t len
,
215 /* The data should be detached - so we need to supply it. */
216 if (data
&& pkcs7_supply_detached_data(pkcs7
, data
, len
) < 0) {
217 pr_err("PKCS#7 signature with non-detached data\n");
222 ret
= pkcs7_verify(pkcs7
, usage
);
227 trusted_keys
= builtin_trusted_keys
;
228 } else if (trusted_keys
== VERIFY_USE_SECONDARY_KEYRING
) {
229 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
230 trusted_keys
= secondary_trusted_keys
;
232 trusted_keys
= builtin_trusted_keys
;
234 } else if (trusted_keys
== VERIFY_USE_PLATFORM_KEYRING
) {
235 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
236 trusted_keys
= platform_trusted_keys
;
242 pr_devel("PKCS#7 platform keyring is not available\n");
246 ret
= pkcs7_validate_trust(pkcs7
, trusted_keys
);
249 pr_devel("PKCS#7 signature not signed with a trusted key\n");
256 ret
= pkcs7_get_content_data(pkcs7
, &data
, &len
, &asn1hdrlen
);
259 pr_devel("PKCS#7 message does not contain data\n");
263 ret
= view_content(ctx
, data
, len
, asn1hdrlen
);
267 pr_devel("<==%s() = %d\n", __func__
, ret
);
272 * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
273 * @data: The data to be verified (NULL if expecting internal data).
274 * @len: Size of @data.
275 * @raw_pkcs7: The PKCS#7 message that is the signature.
276 * @pkcs7_len: The size of @raw_pkcs7.
277 * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
278 * (void *)1UL for all trusted keys).
279 * @usage: The use to which the key is being put.
280 * @view_content: Callback to gain access to content.
281 * @ctx: Context for callback.
283 int verify_pkcs7_signature(const void *data
, size_t len
,
284 const void *raw_pkcs7
, size_t pkcs7_len
,
285 struct key
*trusted_keys
,
286 enum key_being_used_for usage
,
287 int (*view_content
)(void *ctx
,
288 const void *data
, size_t len
,
292 struct pkcs7_message
*pkcs7
;
295 pkcs7
= pkcs7_parse_message(raw_pkcs7
, pkcs7_len
);
297 return PTR_ERR(pkcs7
);
299 ret
= verify_pkcs7_message_sig(data
, len
, pkcs7
, trusted_keys
, usage
,
302 pkcs7_free_message(pkcs7
);
303 pr_devel("<==%s() = %d\n", __func__
, ret
);
306 EXPORT_SYMBOL_GPL(verify_pkcs7_signature
);
308 #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
310 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
311 void __init
set_platform_trusted_keys(struct key
*keyring
)
313 platform_trusted_keys
= keyring
;