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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/key-type.h>
14#include <linux/digsig.h>
15#include <linux/vmalloc.h>
16#include <crypto/public_key.h>
17#include <keys/system_keyring.h>
18
19#include "integrity.h"
20
21static struct key *keyring[INTEGRITY_KEYRING_MAX];
22
23static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
24#ifndef CONFIG_INTEGRITY_TRUSTED_KEYRING
25 "_evm",
26 "_ima",
27#else
28 ".evm",
29 ".ima",
30#endif
31 ".platform",
32};
33
34#ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
35#define restrict_link_to_ima restrict_link_by_builtin_and_secondary_trusted
36#else
37#define restrict_link_to_ima restrict_link_by_builtin_trusted
38#endif
39
40static struct key *integrity_keyring_from_id(const unsigned int id)
41{
42 if (id >= INTEGRITY_KEYRING_MAX)
43 return ERR_PTR(-EINVAL);
44
45 if (!keyring[id]) {
46 keyring[id] =
47 request_key(&key_type_keyring, keyring_name[id], NULL);
48 if (IS_ERR(keyring[id])) {
49 int err = PTR_ERR(keyring[id]);
50 pr_err("no %s keyring: %d\n", keyring_name[id], err);
51 keyring[id] = NULL;
52 return ERR_PTR(err);
53 }
54 }
55
56 return keyring[id];
57}
58
59int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
60 const char *digest, int digestlen)
61{
62 struct key *keyring;
63
64 if (siglen < 2)
65 return -EINVAL;
66
67 keyring = integrity_keyring_from_id(id);
68 if (IS_ERR(keyring))
69 return PTR_ERR(keyring);
70
71 switch (sig[1]) {
72 case 1:
73
74 return digsig_verify(keyring, sig + 1, siglen - 1, digest,
75 digestlen);
76 case 2:
77 return asymmetric_verify(keyring, sig, siglen, digest,
78 digestlen);
79 }
80
81 return -EOPNOTSUPP;
82}
83
84int integrity_modsig_verify(const unsigned int id, const struct modsig *modsig)
85{
86 struct key *keyring;
87
88 keyring = integrity_keyring_from_id(id);
89 if (IS_ERR(keyring))
90 return PTR_ERR(keyring);
91
92 return ima_modsig_verify(keyring, modsig);
93}
94
95static int __init __integrity_init_keyring(const unsigned int id,
96 key_perm_t perm,
97 struct key_restriction *restriction)
98{
99 const struct cred *cred = current_cred();
100 int err = 0;
101
102 keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
103 KGIDT_INIT(0), cred, perm,
104 KEY_ALLOC_NOT_IN_QUOTA, restriction, NULL);
105 if (IS_ERR(keyring[id])) {
106 err = PTR_ERR(keyring[id]);
107 pr_info("Can't allocate %s keyring (%d)\n",
108 keyring_name[id], err);
109 keyring[id] = NULL;
110 } else {
111 if (id == INTEGRITY_KEYRING_PLATFORM)
112 set_platform_trusted_keys(keyring[id]);
113 }
114
115 return err;
116}
117
118int __init integrity_init_keyring(const unsigned int id)
119{
120 struct key_restriction *restriction;
121 key_perm_t perm;
122
123 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW
124 | KEY_USR_READ | KEY_USR_SEARCH;
125
126 if (id == INTEGRITY_KEYRING_PLATFORM) {
127 restriction = NULL;
128 goto out;
129 }
130
131 if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
132 return 0;
133
134 restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
135 if (!restriction)
136 return -ENOMEM;
137
138 restriction->check = restrict_link_to_ima;
139 perm |= KEY_USR_WRITE;
140
141out:
142 return __integrity_init_keyring(id, perm, restriction);
143}
144
145int __init integrity_add_key(const unsigned int id, const void *data,
146 off_t size, key_perm_t perm)
147{
148 key_ref_t key;
149 int rc = 0;
150
151 if (!keyring[id])
152 return -EINVAL;
153
154 key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric",
155 NULL, data, size, perm,
156 KEY_ALLOC_NOT_IN_QUOTA);
157 if (IS_ERR(key)) {
158 rc = PTR_ERR(key);
159 pr_err("Problem loading X.509 certificate %d\n", rc);
160 } else {
161 pr_notice("Loaded X.509 cert '%s'\n",
162 key_ref_to_ptr(key)->description);
163 key_ref_put(key);
164 }
165
166 return rc;
167
168}
169
170int __init integrity_load_x509(const unsigned int id, const char *path)
171{
172 void *data;
173 loff_t size;
174 int rc;
175 key_perm_t perm;
176
177 rc = kernel_read_file_from_path(path, &data, &size, 0,
178 READING_X509_CERTIFICATE);
179 if (rc < 0) {
180 pr_err("Unable to open file: %s (%d)", path, rc);
181 return rc;
182 }
183
184 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;
185
186 pr_info("Loading X.509 certificate: %s\n", path);
187 rc = integrity_add_key(id, (const void *)data, size, perm);
188
189 vfree(data);
190 return rc;
191}
192
193int __init integrity_load_cert(const unsigned int id, const char *source,
194 const void *data, size_t len, key_perm_t perm)
195{
196 if (!data)
197 return -EINVAL;
198
199 pr_info("Loading X.509 certificate: %s\n", source);
200 return integrity_add_key(id, data, len, perm);
201}
202
