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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/err.h>
12 #include <linux/sched.h>
13 #include <linux/slab.h>
14 #include <linux/cred.h>
15 #include <linux/key-type.h>
16 #include <linux/digsig.h>
17 #include <linux/vmalloc.h>
18 #include <crypto/public_key.h>
19 #include <keys/system_keyring.h>
20
21 #include "integrity.h"
22
23 static struct key *keyring[INTEGRITY_KEYRING_MAX];
24
25 static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
26 #ifndef CONFIG_INTEGRITY_TRUSTED_KEYRING
27 "_evm",
28 "_ima",
29 #else
30 ".evm",
31 ".ima",
32 #endif
33 ".platform",
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
integrity_keyring_from_id(const unsigned int id)42 static 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
integrity_digsig_verify(const unsigned int id,const char * sig,int siglen,const char * digest,int digestlen)61 int 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
integrity_modsig_verify(const unsigned int id,const struct modsig * modsig)86 int 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
__integrity_init_keyring(const unsigned int id,key_perm_t perm,struct key_restriction * restriction)97 static 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 }
116
117 return err;
118 }
119
integrity_init_keyring(const unsigned int id)120 int __init integrity_init_keyring(const unsigned int id)
121 {
122 struct key_restriction *restriction;
123 key_perm_t perm;
124 int ret;
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 ret = __integrity_init_keyring(id, perm, restriction);
146 if (ret)
147 kfree(restriction);
148 return ret;
149 }
150
integrity_add_key(const unsigned int id,const void * data,off_t size,key_perm_t perm)151 int __init integrity_add_key(const unsigned int id, const void *data,
152 off_t size, key_perm_t perm)
153 {
154 key_ref_t key;
155 int rc = 0;
156
157 if (!keyring[id])
158 return -EINVAL;
159
160 key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric",
161 NULL, data, size, perm,
162 KEY_ALLOC_NOT_IN_QUOTA);
163 if (IS_ERR(key)) {
164 rc = PTR_ERR(key);
165 pr_err("Problem loading X.509 certificate %d\n", rc);
166 } else {
167 pr_notice("Loaded X.509 cert '%s'\n",
168 key_ref_to_ptr(key)->description);
169 key_ref_put(key);
170 }
171
172 return rc;
173
174 }
175
integrity_load_x509(const unsigned int id,const char * path)176 int __init integrity_load_x509(const unsigned int id, const char *path)
177 {
178 void *data;
179 loff_t size;
180 int rc;
181 key_perm_t perm;
182
183 rc = kernel_read_file_from_path(path, &data, &size, 0,
184 READING_X509_CERTIFICATE);
185 if (rc < 0) {
186 pr_err("Unable to open file: %s (%d)", path, rc);
187 return rc;
188 }
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