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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};
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
41static 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
60int 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
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
85int 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
96static 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
119int __init integrity_init_keyring(const unsigned int id)
120{
121 struct key_restriction *restriction;
122 key_perm_t perm;
123
124 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW
125 | KEY_USR_READ | KEY_USR_SEARCH;
126
127 if (id == INTEGRITY_KEYRING_PLATFORM) {
128 restriction = NULL;
129 goto out;
130 }
131
132 if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
133 return 0;
134
135 restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
136 if (!restriction)
137 return -ENOMEM;
138
139 restriction->check = restrict_link_to_ima;
140 perm |= KEY_USR_WRITE;
141
142out:
143 return __integrity_init_keyring(id, perm, restriction);
144}
145
146int __init integrity_add_key(const unsigned int id, const void *data,
147 off_t size, key_perm_t perm)
148{
149 key_ref_t key;
150 int rc = 0;
151
152 if (!keyring[id])
153 return -EINVAL;
154
155 key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric",
156 NULL, data, size, perm,
157 KEY_ALLOC_NOT_IN_QUOTA);
158 if (IS_ERR(key)) {
159 rc = PTR_ERR(key);
160 pr_err("Problem loading X.509 certificate %d\n", rc);
161 } else {
162 pr_notice("Loaded X.509 cert '%s'\n",
163 key_ref_to_ptr(key)->description);
164 key_ref_put(key);
165 }
166
167 return rc;
168
169}
170
171int __init integrity_load_x509(const unsigned int id, const char *path)
172{
173 void *data = NULL;
174 size_t size;
175 int rc;
176 key_perm_t perm;
177
178 rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL,
179 READING_X509_CERTIFICATE);
180 if (rc < 0) {
181 pr_err("Unable to open file: %s (%d)", path, rc);
182 return rc;
183 }
184 size = rc;
185
186 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;
187
188 pr_info("Loading X.509 certificate: %s\n", path);
189 rc = integrity_add_key(id, (const void *)data, size, perm);
190
191 vfree(data);
192 return rc;
193}
194
195int __init integrity_load_cert(const unsigned int id, const char *source,
196 const void *data, size_t len, key_perm_t perm)
197{
198 if (!data)
199 return -EINVAL;
200
201 pr_info("Loading X.509 certificate: %s\n", source);
202 return integrity_add_key(id, data, len, perm);
203}
204
