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
22 static struct key *keyring[INTEGRITY_KEYRING_MAX];
23
24 static 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 };
34
35 #ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
36 #define restrict_link_to_ima restrict_link_by_builtin_and_secondary_trusted
37 #else
38 #define restrict_link_to_ima restrict_link_by_builtin_trusted
39 #endif
40
integrity_keyring_from_id(const unsigned int id)41 static struct key *integrity_keyring_from_id(const unsigned int id)
42 {
43 if (id >= INTEGRITY_KEYRING_MAX)
44 return ERR_PTR(-EINVAL);
45
46 if (!keyring[id]) {
47 keyring[id] =
48 request_key(&key_type_keyring, keyring_name[id], NULL);
49 if (IS_ERR(keyring[id])) {
50 int err = PTR_ERR(keyring[id]);
51 pr_err("no %s keyring: %d\n", keyring_name[id], err);
52 keyring[id] = NULL;
53 return ERR_PTR(err);
54 }
55 }
56
57 return keyring[id];
58 }
59
integrity_digsig_verify(const unsigned int id, const char *sig, int siglen, const char *digest, int digestlen)60 int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
61 const char *digest, int digestlen)
62 {
63 struct key *keyring;
64
65 if (siglen < 2)
66 return -EINVAL;
67
68 keyring = integrity_keyring_from_id(id);
69 if (IS_ERR(keyring))
70 return PTR_ERR(keyring);
71
72 switch (sig[1]) {
73 case 1:
74 /* v1 API expect signature without xattr type */
75 return digsig_verify(keyring, sig + 1, siglen - 1, digest,
76 digestlen);
77 case 2:
78 return asymmetric_verify(keyring, sig, siglen, digest,
79 digestlen);
80 }
81
82 return -EOPNOTSUPP;
83 }
84
integrity_modsig_verify(const unsigned int id, const struct modsig *modsig)85 int integrity_modsig_verify(const unsigned int id, const struct modsig *modsig)
86 {
87 struct key *keyring;
88
89 keyring = integrity_keyring_from_id(id);
90 if (IS_ERR(keyring))
91 return PTR_ERR(keyring);
92
93 return ima_modsig_verify(keyring, modsig);
94 }
95
__integrity_init_keyring(const unsigned int id, key_perm_t perm, struct key_restriction *restriction)96 static int __init __integrity_init_keyring(const unsigned int id,
97 key_perm_t perm,
98 struct key_restriction *restriction)
99 {
100 const struct cred *cred = current_cred();
101 int err = 0;
102
103 keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
104 KGIDT_INIT(0), cred, perm,
105 KEY_ALLOC_NOT_IN_QUOTA, restriction, NULL);
106 if (IS_ERR(keyring[id])) {
107 err = PTR_ERR(keyring[id]);
108 pr_info("Can't allocate %s keyring (%d)\n",
109 keyring_name[id], err);
110 keyring[id] = NULL;
111 } else {
112 if (id == INTEGRITY_KEYRING_PLATFORM)
113 set_platform_trusted_keys(keyring[id]);
114 }
115
116 return err;
117 }
118
integrity_init_keyring(const unsigned int id)119 int __init integrity_init_keyring(const unsigned int id)
120 {
121 struct key_restriction *restriction;
122 key_perm_t perm;
123 int ret;
124
125 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW
126 | KEY_USR_READ | KEY_USR_SEARCH;
127
128 if (id == INTEGRITY_KEYRING_PLATFORM) {
129 restriction = NULL;
130 goto out;
131 }
132
133 if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
134 return 0;
135
136 restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
137 if (!restriction)
138 return -ENOMEM;
139
140 restriction->check = restrict_link_to_ima;
141 perm |= KEY_USR_WRITE;
142
143 out:
144 ret = __integrity_init_keyring(id, perm, restriction);
145 if (ret)
146 kfree(restriction);
147 return ret;
148 }
149
integrity_add_key(const unsigned int id, const void *data, off_t size, key_perm_t perm)150 int __init integrity_add_key(const unsigned int id, const void *data,
151 off_t size, key_perm_t perm)
152 {
153 key_ref_t key;
154 int rc = 0;
155
156 if (!keyring[id])
157 return -EINVAL;
158
159 key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric",
160 NULL, data, size, perm,
161 KEY_ALLOC_NOT_IN_QUOTA);
162 if (IS_ERR(key)) {
163 rc = PTR_ERR(key);
164 pr_err("Problem loading X.509 certificate %d\n", rc);
165 } else {
166 pr_notice("Loaded X.509 cert '%s'\n",
167 key_ref_to_ptr(key)->description);
168 key_ref_put(key);
169 }
170
171 return rc;
172
173 }
174
integrity_load_x509(const unsigned int id, const char *path)175 int __init integrity_load_x509(const unsigned int id, const char *path)
176 {
177 void *data = NULL;
178 size_t size;
179 int rc;
180 key_perm_t perm;
181
182 rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL,
183 READING_X509_CERTIFICATE);
184 if (rc < 0) {
185 pr_err("Unable to open file: %s (%d)", path, rc);
186 return rc;
187 }
188 size = rc;
189
190 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;
191
192 pr_info("Loading X.509 certificate: %s\n", path);
193 rc = integrity_add_key(id, (const void *)data, size, perm);
194
195 vfree(data);
196 return rc;
197 }
198
integrity_load_cert(const unsigned int id, const char *source, const void *data, size_t len, key_perm_t perm)199 int __init integrity_load_cert(const unsigned int id, const char *source,
200 const void *data, size_t len, key_perm_t perm)
201 {
202 if (!data)
203 return -EINVAL;
204
205 pr_info("Loading X.509 certificate: %s\n", source);
206 return integrity_add_key(id, data, len, perm);
207 }
208