Revert: parisc: Use F_EXTEND() macro in iosapic code
[muen/linux.git] / certs / system_keyring.c
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 <linux/slab.h>
18 #include <linux/verification.h>
19 #include <keys/asymmetric-type.h>
20 #include <keys/system_keyring.h>
21 #include <crypto/pkcs7.h>
22
23 static struct key *builtin_trusted_keys;
24 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
25 static struct key *secondary_trusted_keys;
26 #endif
27 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
28 static struct key *platform_trusted_keys;
29 #endif
30
31 extern __initconst const u8 system_certificate_list[];
32 extern __initconst const unsigned long system_certificate_list_size;
33
34 /**
35  * restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
36  *
37  * Restrict the addition of keys into a keyring based on the key-to-be-added
38  * being vouched for by a key in the built in system keyring.
39  */
40 int restrict_link_by_builtin_trusted(struct key *dest_keyring,
41                                      const struct key_type *type,
42                                      const union key_payload *payload,
43                                      struct key *restriction_key)
44 {
45         return restrict_link_by_signature(dest_keyring, type, payload,
46                                           builtin_trusted_keys);
47 }
48
49 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
50 /**
51  * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
52  *   addition by both builtin and secondary keyrings
53  *
54  * Restrict the addition of keys into a keyring based on the key-to-be-added
55  * being vouched for by a key in either the built-in or the secondary system
56  * keyrings.
57  */
58 int restrict_link_by_builtin_and_secondary_trusted(
59         struct key *dest_keyring,
60         const struct key_type *type,
61         const union key_payload *payload,
62         struct key *restrict_key)
63 {
64         /* If we have a secondary trusted keyring, then that contains a link
65          * through to the builtin keyring and the search will follow that link.
66          */
67         if (type == &key_type_keyring &&
68             dest_keyring == secondary_trusted_keys &&
69             payload == &builtin_trusted_keys->payload)
70                 /* Allow the builtin keyring to be added to the secondary */
71                 return 0;
72
73         return restrict_link_by_signature(dest_keyring, type, payload,
74                                           secondary_trusted_keys);
75 }
76
77 /**
78  * Allocate a struct key_restriction for the "builtin and secondary trust"
79  * keyring. Only for use in system_trusted_keyring_init().
80  */
81 static __init struct key_restriction *get_builtin_and_secondary_restriction(void)
82 {
83         struct key_restriction *restriction;
84
85         restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
86
87         if (!restriction)
88                 panic("Can't allocate secondary trusted keyring restriction\n");
89
90         restriction->check = restrict_link_by_builtin_and_secondary_trusted;
91
92         return restriction;
93 }
94 #endif
95
96 /*
97  * Create the trusted keyrings
98  */
99 static __init int system_trusted_keyring_init(void)
100 {
101         pr_notice("Initialise system trusted keyrings\n");
102
103         builtin_trusted_keys =
104                 keyring_alloc(".builtin_trusted_keys",
105                               KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
106                               ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
107                               KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
108                               KEY_ALLOC_NOT_IN_QUOTA,
109                               NULL, NULL);
110         if (IS_ERR(builtin_trusted_keys))
111                 panic("Can't allocate builtin trusted keyring\n");
112
113 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
114         secondary_trusted_keys =
115                 keyring_alloc(".secondary_trusted_keys",
116                               KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
117                               ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
118                                KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH |
119                                KEY_USR_WRITE),
120                               KEY_ALLOC_NOT_IN_QUOTA,
121                               get_builtin_and_secondary_restriction(),
122                               NULL);
123         if (IS_ERR(secondary_trusted_keys))
124                 panic("Can't allocate secondary trusted keyring\n");
125
126         if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
127                 panic("Can't link trusted keyrings\n");
128 #endif
129
130         return 0;
131 }
132
133 /*
134  * Must be initialised before we try and load the keys into the keyring.
135  */
136 device_initcall(system_trusted_keyring_init);
137
138 /*
139  * Load the compiled-in list of X.509 certificates.
140  */
141 static __init int load_system_certificate_list(void)
142 {
143         key_ref_t key;
144         const u8 *p, *end;
145         size_t plen;
146
147         pr_notice("Loading compiled-in X.509 certificates\n");
148
149         p = system_certificate_list;
150         end = p + system_certificate_list_size;
151         while (p < end) {
152                 /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
153                  * than 256 bytes in size.
154                  */
155                 if (end - p < 4)
156                         goto dodgy_cert;
157                 if (p[0] != 0x30 &&
158                     p[1] != 0x82)
159                         goto dodgy_cert;
160                 plen = (p[2] << 8) | p[3];
161                 plen += 4;
162                 if (plen > end - p)
163                         goto dodgy_cert;
164
165                 key = key_create_or_update(make_key_ref(builtin_trusted_keys, 1),
166                                            "asymmetric",
167                                            NULL,
168                                            p,
169                                            plen,
170                                            ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
171                                            KEY_USR_VIEW | KEY_USR_READ),
172                                            KEY_ALLOC_NOT_IN_QUOTA |
173                                            KEY_ALLOC_BUILT_IN |
174                                            KEY_ALLOC_BYPASS_RESTRICTION);
175                 if (IS_ERR(key)) {
176                         pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
177                                PTR_ERR(key));
178                 } else {
179                         pr_notice("Loaded X.509 cert '%s'\n",
180                                   key_ref_to_ptr(key)->description);
181                         key_ref_put(key);
182                 }
183                 p += plen;
184         }
185
186         return 0;
187
188 dodgy_cert:
189         pr_err("Problem parsing in-kernel X.509 certificate list\n");
190         return 0;
191 }
192 late_initcall(load_system_certificate_list);
193
194 #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
195
196 /**
197  * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
198  * @data: The data to be verified (NULL if expecting internal data).
199  * @len: Size of @data.
200  * @raw_pkcs7: The PKCS#7 message that is the signature.
201  * @pkcs7_len: The size of @raw_pkcs7.
202  * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
203  *                                      (void *)1UL for all trusted keys).
204  * @usage: The use to which the key is being put.
205  * @view_content: Callback to gain access to content.
206  * @ctx: Context for callback.
207  */
208 int verify_pkcs7_signature(const void *data, size_t len,
209                            const void *raw_pkcs7, size_t pkcs7_len,
210                            struct key *trusted_keys,
211                            enum key_being_used_for usage,
212                            int (*view_content)(void *ctx,
213                                                const void *data, size_t len,
214                                                size_t asn1hdrlen),
215                            void *ctx)
216 {
217         struct pkcs7_message *pkcs7;
218         int ret;
219
220         pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
221         if (IS_ERR(pkcs7))
222                 return PTR_ERR(pkcs7);
223
224         /* The data should be detached - so we need to supply it. */
225         if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
226                 pr_err("PKCS#7 signature with non-detached data\n");
227                 ret = -EBADMSG;
228                 goto error;
229         }
230
231         ret = pkcs7_verify(pkcs7, usage);
232         if (ret < 0)
233                 goto error;
234
235         if (!trusted_keys) {
236                 trusted_keys = builtin_trusted_keys;
237         } else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {
238 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
239                 trusted_keys = secondary_trusted_keys;
240 #else
241                 trusted_keys = builtin_trusted_keys;
242 #endif
243         } else if (trusted_keys == VERIFY_USE_PLATFORM_KEYRING) {
244 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
245                 trusted_keys = platform_trusted_keys;
246 #else
247                 trusted_keys = NULL;
248 #endif
249                 if (!trusted_keys) {
250                         ret = -ENOKEY;
251                         pr_devel("PKCS#7 platform keyring is not available\n");
252                         goto error;
253                 }
254         }
255         ret = pkcs7_validate_trust(pkcs7, trusted_keys);
256         if (ret < 0) {
257                 if (ret == -ENOKEY)
258                         pr_devel("PKCS#7 signature not signed with a trusted key\n");
259                 goto error;
260         }
261
262         if (view_content) {
263                 size_t asn1hdrlen;
264
265                 ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
266                 if (ret < 0) {
267                         if (ret == -ENODATA)
268                                 pr_devel("PKCS#7 message does not contain data\n");
269                         goto error;
270                 }
271
272                 ret = view_content(ctx, data, len, asn1hdrlen);
273         }
274
275 error:
276         pkcs7_free_message(pkcs7);
277         pr_devel("<==%s() = %d\n", __func__, ret);
278         return ret;
279 }
280 EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
281
282 #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
283
284 #ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
285 void __init set_platform_trusted_keys(struct key *keyring)
286 {
287         platform_trusted_keys = keyring;
288 }
289 #endif