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Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011 Intel Corporation
4 *
5 * Author:
6 * Dmitry Kasatkin <dmitry.kasatkin@intel.com>
7 */
8
9#include <linux/err.h>
10#include <linux/sched.h>
11#include <linux/slab.h>
12#include <linux/cred.h>
13#include <linux/kernel_read_file.h>
14#include <linux/key-type.h>
15#include <linux/digsig.h>
16#include <linux/vmalloc.h>
17#include <crypto/public_key.h>
18#include <keys/system_keyring.h>
19
20#include "integrity.h"
21
22static struct key *keyring[INTEGRITY_KEYRING_MAX];
23
24static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
25#ifndef CONFIG_INTEGRITY_TRUSTED_KEYRING
26 "_evm",
27 "_ima",
28#else
29 ".evm",
30 ".ima",
31#endif
32 ".platform",
33 ".machine",
34};
35
36#ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
37#define restrict_link_to_ima restrict_link_by_builtin_and_secondary_trusted
38#else
39#define restrict_link_to_ima restrict_link_by_builtin_trusted
40#endif
41
42static struct key *integrity_keyring_from_id(const unsigned int id)
43{
44 if (id >= INTEGRITY_KEYRING_MAX)
45 return ERR_PTR(-EINVAL);
46
47 if (!keyring[id]) {
48 keyring[id] =
49 request_key(&key_type_keyring, keyring_name[id], NULL);
50 if (IS_ERR(keyring[id])) {
51 int err = PTR_ERR(keyring[id]);
52 pr_err("no %s keyring: %d\n", keyring_name[id], err);
53 keyring[id] = NULL;
54 return ERR_PTR(err);
55 }
56 }
57
58 return keyring[id];
59}
60
61int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
62 const char *digest, int digestlen)
63{
64 struct key *keyring;
65
66 if (siglen < 2)
67 return -EINVAL;
68
69 keyring = integrity_keyring_from_id(id);
70 if (IS_ERR(keyring))
71 return PTR_ERR(keyring);
72
73 switch (sig[1]) {
74 case 1:
75 /* v1 API expect signature without xattr type */
76 return digsig_verify(keyring, sig + 1, siglen - 1, digest,
77 digestlen);
78 case 2:
79 return asymmetric_verify(keyring, sig, siglen, digest,
80 digestlen);
81 }
82
83 return -EOPNOTSUPP;
84}
85
86int integrity_modsig_verify(const unsigned int id, const struct modsig *modsig)
87{
88 struct key *keyring;
89
90 keyring = integrity_keyring_from_id(id);
91 if (IS_ERR(keyring))
92 return PTR_ERR(keyring);
93
94 return ima_modsig_verify(keyring, modsig);
95}
96
97static int __init __integrity_init_keyring(const unsigned int id,
98 key_perm_t perm,
99 struct key_restriction *restriction)
100{
101 const struct cred *cred = current_cred();
102 int err = 0;
103
104 keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
105 KGIDT_INIT(0), cred, perm,
106 KEY_ALLOC_NOT_IN_QUOTA, restriction, NULL);
107 if (IS_ERR(keyring[id])) {
108 err = PTR_ERR(keyring[id]);
109 pr_info("Can't allocate %s keyring (%d)\n",
110 keyring_name[id], err);
111 keyring[id] = NULL;
112 } else {
113 if (id == INTEGRITY_KEYRING_PLATFORM)
114 set_platform_trusted_keys(keyring[id]);
115 if (id == INTEGRITY_KEYRING_MACHINE && trust_moklist())
116 set_machine_trusted_keys(keyring[id]);
117 if (id == INTEGRITY_KEYRING_IMA)
118 load_module_cert(keyring[id]);
119 }
120
121 return err;
122}
123
124int __init integrity_init_keyring(const unsigned int id)
125{
126 struct key_restriction *restriction;
127 key_perm_t perm;
128
129 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW
130 | KEY_USR_READ | KEY_USR_SEARCH;
131
132 if (id == INTEGRITY_KEYRING_PLATFORM ||
133 id == INTEGRITY_KEYRING_MACHINE) {
134 restriction = NULL;
135 goto out;
136 }
137
138 if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
139 return 0;
140
141 restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
142 if (!restriction)
143 return -ENOMEM;
144
145 restriction->check = restrict_link_to_ima;
146
147 /*
148 * MOK keys can only be added through a read-only runtime services
149 * UEFI variable during boot. No additional keys shall be allowed to
150 * load into the machine keyring following init from userspace.
151 */
152 if (id != INTEGRITY_KEYRING_MACHINE)
153 perm |= KEY_USR_WRITE;
154
155out:
156 return __integrity_init_keyring(id, perm, restriction);
157}
158
159static int __init integrity_add_key(const unsigned int id, const void *data,
160 off_t size, key_perm_t perm)
161{
162 key_ref_t key;
163 int rc = 0;
164
165 if (!keyring[id])
166 return -EINVAL;
167
168 key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric",
169 NULL, data, size, perm,
170 KEY_ALLOC_NOT_IN_QUOTA);
171 if (IS_ERR(key)) {
172 rc = PTR_ERR(key);
173 pr_err("Problem loading X.509 certificate %d\n", rc);
174 } else {
175 pr_notice("Loaded X.509 cert '%s'\n",
176 key_ref_to_ptr(key)->description);
177 key_ref_put(key);
178 }
179
180 return rc;
181
182}
183
184int __init integrity_load_x509(const unsigned int id, const char *path)
185{
186 void *data = NULL;
187 size_t size;
188 int rc;
189 key_perm_t perm;
190
191 rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL,
192 READING_X509_CERTIFICATE);
193 if (rc < 0) {
194 pr_err("Unable to open file: %s (%d)", path, rc);
195 return rc;
196 }
197 size = rc;
198
199 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;
200
201 pr_info("Loading X.509 certificate: %s\n", path);
202 rc = integrity_add_key(id, (const void *)data, size, perm);
203
204 vfree(data);
205 return rc;
206}
207
208int __init integrity_load_cert(const unsigned int id, const char *source,
209 const void *data, size_t len, key_perm_t perm)
210{
211 if (!data)
212 return -EINVAL;
213
214 pr_info("Loading X.509 certificate: %s\n", source);
215 return integrity_add_key(id, data, len, perm);
216}