1 /* System trusted keyring for trusted public keys
3 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
12 #include <linux/export.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/cred.h>
16 #include <linux/err.h>
17 #include <linux/slab.h>
18 #include <keys/asymmetric-type.h>
19 #include <keys/system_keyring.h>
20 #include <crypto/pkcs7.h>
22 static struct key *builtin_trusted_keys;
23 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
24 static struct key *secondary_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 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
103 KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
104 KEY_ALLOC_NOT_IN_QUOTA,
106 if (IS_ERR(builtin_trusted_keys))
107 panic("Can't allocate builtin trusted keyring\n");
109 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
110 secondary_trusted_keys =
111 keyring_alloc(".secondary_trusted_keys",
112 KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
113 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
114 KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH |
116 KEY_ALLOC_NOT_IN_QUOTA,
117 get_builtin_and_secondary_restriction(),
119 if (IS_ERR(secondary_trusted_keys))
120 panic("Can't allocate secondary trusted keyring\n");
122 if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
123 panic("Can't link trusted keyrings\n");
130 * Must be initialised before we try and load the keys into the keyring.
132 device_initcall(system_trusted_keyring_init);
135 * Load the compiled-in list of X.509 certificates.
137 static __init int load_system_certificate_list(void)
143 pr_notice("Loading compiled-in X.509 certificates\n");
145 p = system_certificate_list;
146 end = p + system_certificate_list_size;
148 /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
149 * than 256 bytes in size.
156 plen = (p[2] << 8) | p[3];
161 key = key_create_or_update(make_key_ref(builtin_trusted_keys, 1),
166 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
167 KEY_USR_VIEW | KEY_USR_READ),
168 KEY_ALLOC_NOT_IN_QUOTA |
170 KEY_ALLOC_BYPASS_RESTRICTION);
172 pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
175 pr_notice("Loaded X.509 cert '%s'\n",
176 key_ref_to_ptr(key)->description);
185 pr_err("Problem parsing in-kernel X.509 certificate list\n");
188 late_initcall(load_system_certificate_list);
190 #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
193 * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
194 * @data: The data to be verified (NULL if expecting internal data).
195 * @len: Size of @data.
196 * @raw_pkcs7: The PKCS#7 message that is the signature.
197 * @pkcs7_len: The size of @raw_pkcs7.
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_signature(const void *data, size_t len,
205 const void *raw_pkcs7, size_t pkcs7_len,
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,
213 struct pkcs7_message *pkcs7;
216 pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
218 return PTR_ERR(pkcs7);
220 /* The data should be detached - so we need to supply it. */
221 if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
222 pr_err("PKCS#7 signature with non-detached data\n");
227 ret = pkcs7_verify(pkcs7, usage);
232 trusted_keys = builtin_trusted_keys;
233 } else if (trusted_keys == (void *)1UL) {
234 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
235 trusted_keys = secondary_trusted_keys;
237 trusted_keys = builtin_trusted_keys;
240 ret = pkcs7_validate_trust(pkcs7, trusted_keys);
243 pr_err("PKCS#7 signature not signed with a trusted key\n");
250 ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
253 pr_devel("PKCS#7 message does not contain data\n");
257 ret = view_content(ctx, data, len, asn1hdrlen);
261 pkcs7_free_message(pkcs7);
262 pr_devel("<==%s() = %d\n", __func__, ret);
265 EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
267 #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */