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 if (id == INTEGRITY_KEYRING_IMA)
115 load_module_cert(keyring[id]);
116 }
117
118 return err;
119 }
120
integrity_init_keyring(const unsigned int id)121 int __init integrity_init_keyring(const unsigned int id)
122 {
123 struct key_restriction *restriction;
124 key_perm_t perm;
125
126 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW
127 | KEY_USR_READ | KEY_USR_SEARCH;
128
129 if (id == INTEGRITY_KEYRING_PLATFORM) {
130 restriction = NULL;
131 goto out;
132 }
133
134 if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
135 return 0;
136
137 restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
138 if (!restriction)
139 return -ENOMEM;
140
141 restriction->check = restrict_link_to_ima;
142 perm |= KEY_USR_WRITE;
143
144 out:
145 return __integrity_init_keyring(id, perm, restriction);
146 }
147
integrity_add_key(const unsigned int id,const void * data,off_t size,key_perm_t perm)148 static int __init integrity_add_key(const unsigned int id, const void *data,
149 off_t size, key_perm_t perm)
150 {
151 key_ref_t key;
152 int rc = 0;
153
154 if (!keyring[id])
155 return -EINVAL;
156
157 key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric",
158 NULL, data, size, perm,
159 KEY_ALLOC_NOT_IN_QUOTA);
160 if (IS_ERR(key)) {
161 rc = PTR_ERR(key);
162 pr_err("Problem loading X.509 certificate %d\n", rc);
163 } else {
164 pr_notice("Loaded X.509 cert '%s'\n",
165 key_ref_to_ptr(key)->description);
166 key_ref_put(key);
167 }
168
169 return rc;
170
171 }
172
integrity_load_x509(const unsigned int id,const char * path)173 int __init integrity_load_x509(const unsigned int id, const char *path)
174 {
175 void *data = NULL;
176 size_t size;
177 int rc;
178 key_perm_t perm;
179
180 rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL,
181 READING_X509_CERTIFICATE);
182 if (rc < 0) {
183 pr_err("Unable to open file: %s (%d)", path, rc);
184 return rc;
185 }
186 size = rc;
187
188 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;
189
190 pr_info("Loading X.509 certificate: %s\n", path);
191 rc = integrity_add_key(id, (const void *)data, size, perm);
192
193 vfree(data);
194 return rc;
195 }
196
integrity_load_cert(const unsigned int id,const char * source,const void * data,size_t len,key_perm_t perm)197 int __init integrity_load_cert(const unsigned int id, const char *source,
198 const void *data, size_t len, key_perm_t perm)
199 {
200 if (!data)
201 return -EINVAL;
202
203 pr_info("Loading X.509 certificate: %s\n", source);
204 return integrity_add_key(id, data, len, perm);
205 }
206
