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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>
19#include <crypto/pkcs7.h>
20
21struct key *system_trusted_keyring;
22EXPORT_SYMBOL_GPL(system_trusted_keyring);
23
24extern __initconst const u8 system_certificate_list[];
25extern __initconst const unsigned long system_certificate_list_size;
26
27/*
28 * Load the compiled-in keys
29 */
30static __init int system_trusted_keyring_init(void)
31{
32 pr_notice("Initialise system trusted keyring\n");
33
34 system_trusted_keyring =
35 keyring_alloc(".system_keyring",
36 KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
37 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
38 KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
39 KEY_ALLOC_NOT_IN_QUOTA, NULL);
40 if (IS_ERR(system_trusted_keyring))
41 panic("Can't allocate system trusted keyring\n");
42
43 set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
44 return 0;
45}
46
47/*
48 * Must be initialised before we try and load the keys into the keyring.
49 */
50device_initcall(system_trusted_keyring_init);
51
52/*
53 * Load the compiled-in list of X.509 certificates.
54 */
55static __init int load_system_certificate_list(void)
56{
57 key_ref_t key;
58 const u8 *p, *end;
59 size_t plen;
60
61 pr_notice("Loading compiled-in X.509 certificates\n");
62
63 p = system_certificate_list;
64 end = p + system_certificate_list_size;
65 while (p < end) {
66 /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
67 * than 256 bytes in size.
68 */
69 if (end - p < 4)
70 goto dodgy_cert;
71 if (p[0] != 0x30 &&
72 p[1] != 0x82)
73 goto dodgy_cert;
74 plen = (p[2] << 8) | p[3];
75 plen += 4;
76 if (plen > end - p)
77 goto dodgy_cert;
78
79 key = key_create_or_update(make_key_ref(system_trusted_keyring, 1),
80 "asymmetric",
81 NULL,
82 p,
83 plen,
84 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
85 KEY_USR_VIEW | KEY_USR_READ),
86 KEY_ALLOC_NOT_IN_QUOTA |
87 KEY_ALLOC_TRUSTED |
88 KEY_ALLOC_BUILT_IN);
89 if (IS_ERR(key)) {
90 pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
91 PTR_ERR(key));
92 } else {
93 pr_notice("Loaded X.509 cert '%s'\n",
94 key_ref_to_ptr(key)->description);
95 key_ref_put(key);
96 }
97 p += plen;
98 }
99
100 return 0;
101
102dodgy_cert:
103 pr_err("Problem parsing in-kernel X.509 certificate list\n");
104 return 0;
105}
106late_initcall(load_system_certificate_list);
107
108#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
109
110/**
111 * Verify a PKCS#7-based signature on system data.
112 * @data: The data to be verified.
113 * @len: Size of @data.
114 * @raw_pkcs7: The PKCS#7 message that is the signature.
115 * @pkcs7_len: The size of @raw_pkcs7.
116 * @usage: The use to which the key is being put.
117 */
118int system_verify_data(const void *data, unsigned long len,
119 const void *raw_pkcs7, size_t pkcs7_len,
120 enum key_being_used_for usage)
121{
122 struct pkcs7_message *pkcs7;
123 bool trusted;
124 int ret;
125
126 pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
127 if (IS_ERR(pkcs7))
128 return PTR_ERR(pkcs7);
129
130 /* The data should be detached - so we need to supply it. */
131 if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
132 pr_err("PKCS#7 signature with non-detached data\n");
133 ret = -EBADMSG;
134 goto error;
135 }
136
137 ret = pkcs7_verify(pkcs7, usage);
138 if (ret < 0)
139 goto error;
140
141 ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
142 if (ret < 0)
143 goto error;
144
145 if (!trusted) {
146 pr_err("PKCS#7 signature not signed with a trusted key\n");
147 ret = -ENOKEY;
148 }
149
150error:
151 pkcs7_free_message(pkcs7);
152 pr_devel("<==%s() = %d\n", __func__, ret);
153 return ret;
154}
155EXPORT_SYMBOL_GPL(system_verify_data);
156
157#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
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>
19#include <crypto/pkcs7.h>
20
21static struct key *builtin_trusted_keys;
22#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
23static struct key *secondary_trusted_keys;
24#endif
25
26extern __initconst const u8 system_certificate_list[];
27extern __initconst const unsigned long system_certificate_list_size;
28
29/**
30 * restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
31 *
32 * Restrict the addition of keys into a keyring based on the key-to-be-added
33 * being vouched for by a key in the built in system keyring.
34 */
35int restrict_link_by_builtin_trusted(struct key *keyring,
36 const struct key_type *type,
37 const union key_payload *payload)
38{
39 return restrict_link_by_signature(builtin_trusted_keys, type, payload);
40}
41
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 */
51int 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
69/*
70 * Create the trusted keyrings
71 */
72static __init int system_trusted_keyring_init(void)
73{
74 pr_notice("Initialise system trusted keyrings\n");
75
76 builtin_trusted_keys =
77 keyring_alloc(".builtin_trusted_keys",
78 KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
79 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
80 KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
81 KEY_ALLOC_NOT_IN_QUOTA,
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
103 return 0;
104}
105
106/*
107 * Must be initialised before we try and load the keys into the keyring.
108 */
109device_initcall(system_trusted_keyring_init);
110
111/*
112 * Load the compiled-in list of X.509 certificates.
113 */
114static __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
122 p = system_certificate_list;
123 end = p + system_certificate_list_size;
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
138 key = key_create_or_update(make_key_ref(builtin_trusted_keys, 1),
139 "asymmetric",
140 NULL,
141 p,
142 plen,
143 ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
144 KEY_USR_VIEW | KEY_USR_READ),
145 KEY_ALLOC_NOT_IN_QUOTA |
146 KEY_ALLOC_BUILT_IN |
147 KEY_ALLOC_BYPASS_RESTRICTION);
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
161dodgy_cert:
162 pr_err("Problem parsing in-kernel X.509 certificate list\n");
163 return 0;
164}
165late_initcall(load_system_certificate_list);
166
167#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
168
169/**
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).
172 * @len: Size of @data.
173 * @raw_pkcs7: The PKCS#7 message that is the signature.
174 * @pkcs7_len: The size of @raw_pkcs7.
175 * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
176 * (void *)1UL for all trusted keys).
177 * @usage: The use to which the key is being put.
178 * @view_content: Callback to gain access to content.
179 * @ctx: Context for callback.
180 */
181int verify_pkcs7_signature(const void *data, size_t len,
182 const void *raw_pkcs7, size_t pkcs7_len,
183 struct key *trusted_keys,
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)
189{
190 struct pkcs7_message *pkcs7;
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. */
198 if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
199 pr_err("PKCS#7 signature with non-detached data\n");
200 ret = -EBADMSG;
201 goto error;
202 }
203
204 ret = pkcs7_verify(pkcs7, usage);
205 if (ret < 0)
206 goto error;
207
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 }
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");
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);
235 }
236
237error:
238 pkcs7_free_message(pkcs7);
239 pr_devel("<==%s() = %d\n", __func__, ret);
240 return ret;
241}
242EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
243
244#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */