Commit | Line | Data |
---|---|---|
b56e5a17 DH |
1 | /* System trusted keyring for trusted public keys |
2 | * | |
3 | * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
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. | |
10 | */ | |
11 | ||
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 <keys/asymmetric-type.h> | |
18 | #include <keys/system_keyring.h> | |
091f6e26 | 19 | #include <crypto/pkcs7.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 | |
b56e5a17 DH |
25 | |
26 | extern __initconst const u8 system_certificate_list[]; | |
62226983 | 27 | extern __initconst const unsigned long system_certificate_list_size; |
b56e5a17 | 28 | |
a511e1af | 29 | /** |
d3bfe841 | 30 | * restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA |
a511e1af DH |
31 | * |
32 | * Restrict the addition of keys into a keyring based on the key-to-be-added | |
d3bfe841 | 33 | * being vouched for by a key in the built in system keyring. |
a511e1af DH |
34 | */ |
35 | int restrict_link_by_builtin_trusted(struct key *keyring, | |
36 | const struct key_type *type, | |
a511e1af DH |
37 | const union key_payload *payload) |
38 | { | |
d3bfe841 | 39 | return restrict_link_by_signature(builtin_trusted_keys, type, payload); |
a511e1af DH |
40 | } |
41 | ||
d3bfe841 DH |
42 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING |
43 | /** | |
44 | * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring | |
45 | * addition by both builtin and secondary keyrings | |
46 | * | |
47 | * Restrict the addition of keys into a keyring based on the key-to-be-added | |
48 | * being vouched for by a key in either the built-in or the secondary system | |
49 | * keyrings. | |
50 | */ | |
51 | int restrict_link_by_builtin_and_secondary_trusted( | |
52 | struct key *keyring, | |
53 | const struct key_type *type, | |
54 | const union key_payload *payload) | |
55 | { | |
56 | /* If we have a secondary trusted keyring, then that contains a link | |
57 | * through to the builtin keyring and the search will follow that link. | |
58 | */ | |
59 | if (type == &key_type_keyring && | |
60 | keyring == secondary_trusted_keys && | |
61 | payload == &builtin_trusted_keys->payload) | |
62 | /* Allow the builtin keyring to be added to the secondary */ | |
63 | return 0; | |
64 | ||
65 | return restrict_link_by_signature(secondary_trusted_keys, type, payload); | |
66 | } | |
67 | #endif | |
68 | ||
b56e5a17 | 69 | /* |
d3bfe841 | 70 | * Create the trusted keyrings |
b56e5a17 DH |
71 | */ |
72 | static __init int system_trusted_keyring_init(void) | |
73 | { | |
d3bfe841 | 74 | pr_notice("Initialise system trusted keyrings\n"); |
b56e5a17 | 75 | |
d3bfe841 DH |
76 | builtin_trusted_keys = |
77 | keyring_alloc(".builtin_trusted_keys", | |
b56e5a17 DH |
78 | KUIDT_INIT(0), KGIDT_INIT(0), current_cred(), |
79 | ((KEY_POS_ALL & ~KEY_POS_SETATTR) | | |
af34cb0c | 80 | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH), |
5ac7eace | 81 | KEY_ALLOC_NOT_IN_QUOTA, |
d3bfe841 DH |
82 | NULL, NULL); |
83 | if (IS_ERR(builtin_trusted_keys)) | |
84 | panic("Can't allocate builtin trusted keyring\n"); | |
85 | ||
86 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING | |
87 | secondary_trusted_keys = | |
88 | keyring_alloc(".secondary_trusted_keys", | |
89 | KUIDT_INIT(0), KGIDT_INIT(0), current_cred(), | |
90 | ((KEY_POS_ALL & ~KEY_POS_SETATTR) | | |
91 | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH | | |
92 | KEY_USR_WRITE), | |
93 | KEY_ALLOC_NOT_IN_QUOTA, | |
94 | restrict_link_by_builtin_and_secondary_trusted, | |
95 | NULL); | |
96 | if (IS_ERR(secondary_trusted_keys)) | |
97 | panic("Can't allocate secondary trusted keyring\n"); | |
98 | ||
99 | if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0) | |
100 | panic("Can't link trusted keyrings\n"); | |
101 | #endif | |
102 | ||
b56e5a17 DH |
103 | return 0; |
104 | } | |
105 | ||
106 | /* | |
107 | * Must be initialised before we try and load the keys into the keyring. | |
108 | */ | |
109 | device_initcall(system_trusted_keyring_init); | |
110 | ||
111 | /* | |
112 | * Load the compiled-in list of X.509 certificates. | |
113 | */ | |
114 | static __init int load_system_certificate_list(void) | |
115 | { | |
116 | key_ref_t key; | |
117 | const u8 *p, *end; | |
118 | size_t plen; | |
119 | ||
120 | pr_notice("Loading compiled-in X.509 certificates\n"); | |
121 | ||
b56e5a17 | 122 | p = system_certificate_list; |
62226983 | 123 | end = p + system_certificate_list_size; |
b56e5a17 DH |
124 | while (p < end) { |
125 | /* Each cert begins with an ASN.1 SEQUENCE tag and must be more | |
126 | * than 256 bytes in size. | |
127 | */ | |
128 | if (end - p < 4) | |
129 | goto dodgy_cert; | |
130 | if (p[0] != 0x30 && | |
131 | p[1] != 0x82) | |
132 | goto dodgy_cert; | |
133 | plen = (p[2] << 8) | p[3]; | |
134 | plen += 4; | |
135 | if (plen > end - p) | |
136 | goto dodgy_cert; | |
137 | ||
d3bfe841 | 138 | key = key_create_or_update(make_key_ref(builtin_trusted_keys, 1), |
b56e5a17 DH |
139 | "asymmetric", |
140 | NULL, | |
141 | p, | |
142 | plen, | |
af34cb0c MZ |
143 | ((KEY_POS_ALL & ~KEY_POS_SETATTR) | |
144 | KEY_USR_VIEW | KEY_USR_READ), | |
008643b8 | 145 | KEY_ALLOC_NOT_IN_QUOTA | |
5ac7eace DH |
146 | KEY_ALLOC_BUILT_IN | |
147 | KEY_ALLOC_BYPASS_RESTRICTION); | |
b56e5a17 DH |
148 | if (IS_ERR(key)) { |
149 | pr_err("Problem loading in-kernel X.509 certificate (%ld)\n", | |
150 | PTR_ERR(key)); | |
151 | } else { | |
152 | pr_notice("Loaded X.509 cert '%s'\n", | |
153 | key_ref_to_ptr(key)->description); | |
154 | key_ref_put(key); | |
155 | } | |
156 | p += plen; | |
157 | } | |
158 | ||
159 | return 0; | |
160 | ||
161 | dodgy_cert: | |
162 | pr_err("Problem parsing in-kernel X.509 certificate list\n"); | |
163 | return 0; | |
164 | } | |
165 | late_initcall(load_system_certificate_list); | |
091f6e26 DH |
166 | |
167 | #ifdef CONFIG_SYSTEM_DATA_VERIFICATION | |
168 | ||
169 | /** | |
e68503bd DH |
170 | * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data. |
171 | * @data: The data to be verified (NULL if expecting internal data). | |
091f6e26 DH |
172 | * @len: Size of @data. |
173 | * @raw_pkcs7: The PKCS#7 message that is the signature. | |
174 | * @pkcs7_len: The size of @raw_pkcs7. | |
d3bfe841 DH |
175 | * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, |
176 | * (void *)1UL for all trusted keys). | |
99db4435 | 177 | * @usage: The use to which the key is being put. |
e68503bd DH |
178 | * @view_content: Callback to gain access to content. |
179 | * @ctx: Context for callback. | |
091f6e26 | 180 | */ |
e68503bd DH |
181 | int verify_pkcs7_signature(const void *data, size_t len, |
182 | const void *raw_pkcs7, size_t pkcs7_len, | |
183 | struct key *trusted_keys, | |
e68503bd DH |
184 | enum key_being_used_for usage, |
185 | int (*view_content)(void *ctx, | |
186 | const void *data, size_t len, | |
187 | size_t asn1hdrlen), | |
188 | void *ctx) | |
091f6e26 DH |
189 | { |
190 | struct pkcs7_message *pkcs7; | |
091f6e26 DH |
191 | int ret; |
192 | ||
193 | pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len); | |
194 | if (IS_ERR(pkcs7)) | |
195 | return PTR_ERR(pkcs7); | |
196 | ||
197 | /* The data should be detached - so we need to supply it. */ | |
e68503bd | 198 | if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) { |
091f6e26 DH |
199 | pr_err("PKCS#7 signature with non-detached data\n"); |
200 | ret = -EBADMSG; | |
201 | goto error; | |
202 | } | |
203 | ||
99db4435 | 204 | ret = pkcs7_verify(pkcs7, usage); |
091f6e26 DH |
205 | if (ret < 0) |
206 | goto error; | |
207 | ||
d3bfe841 DH |
208 | if (!trusted_keys) { |
209 | trusted_keys = builtin_trusted_keys; | |
210 | } else if (trusted_keys == (void *)1UL) { | |
211 | #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING | |
212 | trusted_keys = secondary_trusted_keys; | |
213 | #else | |
214 | trusted_keys = builtin_trusted_keys; | |
215 | #endif | |
216 | } | |
bda850cd DH |
217 | ret = pkcs7_validate_trust(pkcs7, trusted_keys); |
218 | if (ret < 0) { | |
219 | if (ret == -ENOKEY) | |
220 | pr_err("PKCS#7 signature not signed with a trusted key\n"); | |
e68503bd DH |
221 | goto error; |
222 | } | |
223 | ||
224 | if (view_content) { | |
225 | size_t asn1hdrlen; | |
226 | ||
227 | ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen); | |
228 | if (ret < 0) { | |
229 | if (ret == -ENODATA) | |
230 | pr_devel("PKCS#7 message does not contain data\n"); | |
231 | goto error; | |
232 | } | |
233 | ||
234 | ret = view_content(ctx, data, len, asn1hdrlen); | |
091f6e26 DH |
235 | } |
236 | ||
237 | error: | |
238 | pkcs7_free_message(pkcs7); | |
239 | pr_devel("<==%s() = %d\n", __func__, ret); | |
240 | return ret; | |
241 | } | |
e68503bd | 242 | EXPORT_SYMBOL_GPL(verify_pkcs7_signature); |
091f6e26 DH |
243 | |
244 | #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */ |