tools/power turbostat: KNL workaround for %Busy and Avg_MHz
[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 <keys/asymmetric-type.h>
18 #include <keys/system_keyring.h>
19 #include <crypto/pkcs7.h>
20
21 struct key *system_trusted_keyring;
22 EXPORT_SYMBOL_GPL(system_trusted_keyring);
23
24 extern __initconst const u8 system_certificate_list[];
25 extern __initconst const unsigned long system_certificate_list_size;
26
27 /*
28  * Load the compiled-in keys
29  */
30 static __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  */
50 device_initcall(system_trusted_keyring_init);
51
52 /*
53  * Load the compiled-in list of X.509 certificates.
54  */
55 static __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                 if (IS_ERR(key)) {
89                         pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
90                                PTR_ERR(key));
91                 } else {
92                         set_bit(KEY_FLAG_BUILTIN, &key_ref_to_ptr(key)->flags);
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
102 dodgy_cert:
103         pr_err("Problem parsing in-kernel X.509 certificate list\n");
104         return 0;
105 }
106 late_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  */
118 int 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
150 error:
151         pkcs7_free_message(pkcs7);
152         pr_devel("<==%s() = %d\n", __func__, ret);
153         return ret;
154 }
155 EXPORT_SYMBOL_GPL(system_verify_data);
156
157 #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */