tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2011 Intel Corporation
3 *
4 * Author:
5 * Dmitry Kasatkin <dmitry.kasatkin@intel.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, version 2 of the License.
10 *
11 */
12
13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15#include <linux/err.h>
16#include <linux/sched.h>
17#include <linux/slab.h>
18#include <linux/cred.h>
19#include <linux/key-type.h>
20#include <linux/digsig.h>
21#include <linux/vmalloc.h>
22#include <crypto/public_key.h>
23#include <keys/system_keyring.h>
24
25#include "integrity.h"
26
27static struct key *keyring[INTEGRITY_KEYRING_MAX];
28
29static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
30#ifndef CONFIG_INTEGRITY_TRUSTED_KEYRING
31 "_evm",
32 "_ima",
33#else
34 ".evm",
35 ".ima",
36#endif
37 ".platform",
38};
39
40#ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
41#define restrict_link_to_ima restrict_link_by_builtin_and_secondary_trusted
42#else
43#define restrict_link_to_ima restrict_link_by_builtin_trusted
44#endif
45
46int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
47 const char *digest, int digestlen)
48{
49 if (id >= INTEGRITY_KEYRING_MAX || siglen < 2)
50 return -EINVAL;
51
52 if (!keyring[id]) {
53 keyring[id] =
54 request_key(&key_type_keyring, keyring_name[id], NULL);
55 if (IS_ERR(keyring[id])) {
56 int err = PTR_ERR(keyring[id]);
57 pr_err("no %s keyring: %d\n", keyring_name[id], err);
58 keyring[id] = NULL;
59 return err;
60 }
61 }
62
63 switch (sig[1]) {
64 case 1:
65 /* v1 API expect signature without xattr type */
66 return digsig_verify(keyring[id], sig + 1, siglen - 1,
67 digest, digestlen);
68 case 2:
69 return asymmetric_verify(keyring[id], sig, siglen,
70 digest, digestlen);
71 }
72
73 return -EOPNOTSUPP;
74}
75
76static int __integrity_init_keyring(const unsigned int id, key_perm_t perm,
77 struct key_restriction *restriction)
78{
79 const struct cred *cred = current_cred();
80 int err = 0;
81
82 keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
83 KGIDT_INIT(0), cred, perm,
84 KEY_ALLOC_NOT_IN_QUOTA, restriction, NULL);
85 if (IS_ERR(keyring[id])) {
86 err = PTR_ERR(keyring[id]);
87 pr_info("Can't allocate %s keyring (%d)\n",
88 keyring_name[id], err);
89 keyring[id] = NULL;
90 } else {
91 if (id == INTEGRITY_KEYRING_PLATFORM)
92 set_platform_trusted_keys(keyring[id]);
93 }
94
95 return err;
96}
97
98int __init integrity_init_keyring(const unsigned int id)
99{
100 struct key_restriction *restriction;
101 key_perm_t perm;
102
103 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW
104 | KEY_USR_READ | KEY_USR_SEARCH;
105
106 if (id == INTEGRITY_KEYRING_PLATFORM) {
107 restriction = NULL;
108 goto out;
109 }
110
111 if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
112 return 0;
113
114 restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
115 if (!restriction)
116 return -ENOMEM;
117
118 restriction->check = restrict_link_to_ima;
119 perm |= KEY_USR_WRITE;
120
121out:
122 return __integrity_init_keyring(id, perm, restriction);
123}
124
125int __init integrity_add_key(const unsigned int id, const void *data,
126 off_t size, key_perm_t perm)
127{
128 key_ref_t key;
129 int rc = 0;
130
131 if (!keyring[id])
132 return -EINVAL;
133
134 key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric",
135 NULL, data, size, perm,
136 KEY_ALLOC_NOT_IN_QUOTA);
137 if (IS_ERR(key)) {
138 rc = PTR_ERR(key);
139 pr_err("Problem loading X.509 certificate %d\n", rc);
140 } else {
141 pr_notice("Loaded X.509 cert '%s'\n",
142 key_ref_to_ptr(key)->description);
143 key_ref_put(key);
144 }
145
146 return rc;
147
148}
149
150int __init integrity_load_x509(const unsigned int id, const char *path)
151{
152 void *data;
153 loff_t size;
154 int rc;
155 key_perm_t perm;
156
157 rc = kernel_read_file_from_path(path, &data, &size, 0,
158 READING_X509_CERTIFICATE);
159 if (rc < 0) {
160 pr_err("Unable to open file: %s (%d)", path, rc);
161 return rc;
162 }
163
164 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;
165
166 pr_info("Loading X.509 certificate: %s\n", path);
167 rc = integrity_add_key(id, (const void *)data, size, perm);
168
169 vfree(data);
170 return rc;
171}
172
173int __init integrity_load_cert(const unsigned int id, const char *source,
174 const void *data, size_t len, key_perm_t perm)
175{
176 if (!data)
177 return -EINVAL;
178
179 pr_info("Loading X.509 certificate: %s\n", source);
180 return integrity_add_key(id, data, len, perm);
181}