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
22#include "integrity.h"
23
24static struct key *keyring[INTEGRITY_KEYRING_MAX];
25
26static const char *keyring_name[INTEGRITY_KEYRING_MAX] = {
27	"_evm",
28	"_module",
29#ifndef CONFIG_IMA_TRUSTED_KEYRING
30	"_ima",
31#else
32	".ima",
33#endif
34};
35
36int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
37			    const char *digest, int digestlen)
38{
39	if (id >= INTEGRITY_KEYRING_MAX)
40		return -EINVAL;
41
42	if (!keyring[id]) {
43		keyring[id] =
44			request_key(&key_type_keyring, keyring_name[id], NULL);
45		if (IS_ERR(keyring[id])) {
46			int err = PTR_ERR(keyring[id]);
47			pr_err("no %s keyring: %d\n", keyring_name[id], err);
48			keyring[id] = NULL;
49			return err;
50		}
51	}
52
53	switch (sig[1]) {
54	case 1:
55		/* v1 API expect signature without xattr type */
56		return digsig_verify(keyring[id], sig + 1, siglen - 1,
57				     digest, digestlen);
58	case 2:
59		return asymmetric_verify(keyring[id], sig, siglen,
60					 digest, digestlen);
61	}
62
63	return -EOPNOTSUPP;
64}
65
66int __init integrity_init_keyring(const unsigned int id)
67{
68	const struct cred *cred = current_cred();
69	int err = 0;
70
71	keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
72				    KGIDT_INIT(0), cred,
73				    ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
74				     KEY_USR_VIEW | KEY_USR_READ |
75				     KEY_USR_WRITE | KEY_USR_SEARCH),
76				    KEY_ALLOC_NOT_IN_QUOTA, NULL);
77	if (!IS_ERR(keyring[id]))
78		set_bit(KEY_FLAG_TRUSTED_ONLY, &keyring[id]->flags);
79	else {
80		err = PTR_ERR(keyring[id]);
81		pr_info("Can't allocate %s keyring (%d)\n",
82			keyring_name[id], err);
83		keyring[id] = NULL;
84	}
85	return err;
86}
87
88int __init integrity_load_x509(const unsigned int id, char *path)
89{
90	key_ref_t key;
91	char *data;
92	int rc;
93
94	if (!keyring[id])
95		return -EINVAL;
96
97	rc = integrity_read_file(path, &data);
98	if (rc < 0)
99		return rc;
100
101	key = key_create_or_update(make_key_ref(keyring[id], 1),
102				   "asymmetric",
103				   NULL,
104				   data,
105				   rc,
106				   ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
107				    KEY_USR_VIEW | KEY_USR_READ),
108				   KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_TRUSTED);
109	if (IS_ERR(key)) {
110		rc = PTR_ERR(key);
111		pr_err("Problem loading X.509 certificate (%d): %s\n",
112		       rc, path);
113	} else {
114		pr_notice("Loaded X.509 cert '%s': %s\n",
115			  key_ref_to_ptr(key)->description, path);
116		key_ref_put(key);
117	}
118	kfree(data);
119	return 0;
120}
121