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/verification.h>
15 #include <keys/asymmetric-type.h>
16 #include <keys/system_keyring.h>
17 #include <crypto/pkcs7.h>
19 static struct key
*builtin_trusted_keys
;
20 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
21 static struct key
*secondary_trusted_keys
;
23 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
24 static struct key
*platform_trusted_keys
;
27 extern __initconst
const u8 system_certificate_list
[];
28 extern __initconst
const unsigned long system_certificate_list_size
;
31 * restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
33 * Restrict the addition of keys into a keyring based on the key-to-be-added
34 * being vouched for by a key in the built in system keyring.
36 int restrict_link_by_builtin_trusted(struct key
*dest_keyring
,
37 const struct key_type
*type
,
38 const union key_payload
*payload
,
39 struct key
*restriction_key
)
41 return restrict_link_by_signature(dest_keyring
, type
, payload
,
42 builtin_trusted_keys
);
45 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
47 * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
48 * addition by both builtin and secondary keyrings
50 * Restrict the addition of keys into a keyring based on the key-to-be-added
51 * being vouched for by a key in either the built-in or the secondary system
54 int restrict_link_by_builtin_and_secondary_trusted(
55 struct key
*dest_keyring
,
56 const struct key_type
*type
,
57 const union key_payload
*payload
,
58 struct key
*restrict_key
)
60 /* If we have a secondary trusted keyring, then that contains a link
61 * through to the builtin keyring and the search will follow that link.
63 if (type
== &key_type_keyring
&&
64 dest_keyring
== secondary_trusted_keys
&&
65 payload
== &builtin_trusted_keys
->payload
)
66 /* Allow the builtin keyring to be added to the secondary */
69 return restrict_link_by_signature(dest_keyring
, type
, payload
,
70 secondary_trusted_keys
);
74 * Allocate a struct key_restriction for the "builtin and secondary trust"
75 * keyring. Only for use in system_trusted_keyring_init().
77 static __init
struct key_restriction
*get_builtin_and_secondary_restriction(void)
79 struct key_restriction
*restriction
;
81 restriction
= kzalloc(sizeof(struct key_restriction
), GFP_KERNEL
);
84 panic("Can't allocate secondary trusted keyring restriction\n");
86 restriction
->check
= restrict_link_by_builtin_and_secondary_trusted
;
93 * Create the trusted keyrings
95 static __init
int system_trusted_keyring_init(void)
97 pr_notice("Initialise system trusted keyrings\n");
99 builtin_trusted_keys
=
100 keyring_alloc(".builtin_trusted_keys",
101 KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
102 &internal_key_acl
, KEY_ALLOC_NOT_IN_QUOTA
,
104 if (IS_ERR(builtin_trusted_keys
))
105 panic("Can't allocate builtin trusted keyring\n");
107 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
108 secondary_trusted_keys
=
109 keyring_alloc(".secondary_trusted_keys",
110 KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
111 &internal_writable_keyring_acl
, KEY_ALLOC_NOT_IN_QUOTA
,
112 get_builtin_and_secondary_restriction(),
114 if (IS_ERR(secondary_trusted_keys
))
115 panic("Can't allocate secondary trusted keyring\n");
117 if (key_link(secondary_trusted_keys
, builtin_trusted_keys
) < 0)
118 panic("Can't link trusted keyrings\n");
125 * Must be initialised before we try and load the keys into the keyring.
127 device_initcall(system_trusted_keyring_init
);
130 * Load the compiled-in list of X.509 certificates.
132 static __init
int load_system_certificate_list(void)
138 pr_notice("Loading compiled-in X.509 certificates\n");
140 p
= system_certificate_list
;
141 end
= p
+ system_certificate_list_size
;
143 /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
144 * than 256 bytes in size.
151 plen
= (p
[2] << 8) | p
[3];
156 key
= key_create_or_update(make_key_ref(builtin_trusted_keys
, 1),
162 KEY_ALLOC_NOT_IN_QUOTA
|
164 KEY_ALLOC_BYPASS_RESTRICTION
);
166 pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
169 pr_notice("Loaded X.509 cert '%s'\n",
170 key_ref_to_ptr(key
)->description
);
179 pr_err("Problem parsing in-kernel X.509 certificate list\n");
182 late_initcall(load_system_certificate_list
);
184 #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
187 * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
188 * @data: The data to be verified (NULL if expecting internal data).
189 * @len: Size of @data.
190 * @raw_pkcs7: The PKCS#7 message that is the signature.
191 * @pkcs7_len: The size of @raw_pkcs7.
192 * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
193 * (void *)1UL for all trusted keys).
194 * @usage: The use to which the key is being put.
195 * @view_content: Callback to gain access to content.
196 * @ctx: Context for callback.
198 int verify_pkcs7_signature(const void *data
, size_t len
,
199 const void *raw_pkcs7
, size_t pkcs7_len
,
200 struct key
*trusted_keys
,
201 enum key_being_used_for usage
,
202 int (*view_content
)(void *ctx
,
203 const void *data
, size_t len
,
207 struct pkcs7_message
*pkcs7
;
210 pkcs7
= pkcs7_parse_message(raw_pkcs7
, pkcs7_len
);
212 return PTR_ERR(pkcs7
);
214 /* The data should be detached - so we need to supply it. */
215 if (data
&& pkcs7_supply_detached_data(pkcs7
, data
, len
) < 0) {
216 pr_err("PKCS#7 signature with non-detached data\n");
221 ret
= pkcs7_verify(pkcs7
, usage
);
226 trusted_keys
= builtin_trusted_keys
;
227 } else if (trusted_keys
== VERIFY_USE_SECONDARY_KEYRING
) {
228 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
229 trusted_keys
= secondary_trusted_keys
;
231 trusted_keys
= builtin_trusted_keys
;
233 } else if (trusted_keys
== VERIFY_USE_PLATFORM_KEYRING
) {
234 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
235 trusted_keys
= platform_trusted_keys
;
241 pr_devel("PKCS#7 platform keyring is not available\n");
245 ret
= pkcs7_validate_trust(pkcs7
, trusted_keys
);
248 pr_devel("PKCS#7 signature not signed with a trusted key\n");
255 ret
= pkcs7_get_content_data(pkcs7
, &data
, &len
, &asn1hdrlen
);
258 pr_devel("PKCS#7 message does not contain data\n");
262 ret
= view_content(ctx
, data
, len
, asn1hdrlen
);
266 pkcs7_free_message(pkcs7
);
267 pr_devel("<==%s() = %d\n", __func__
, ret
);
270 EXPORT_SYMBOL_GPL(verify_pkcs7_signature
);
272 #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
274 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
275 void __init
set_platform_trusted_keys(struct key
*keyring
)
277 platform_trusted_keys
= keyring
;