summaryrefslogtreecommitdiff
path: root/security/apparmor/crypto.c
blob: b498ed3024610f406d15a204fec2c650bc8c1ac8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
// SPDX-License-Identifier: GPL-2.0-only
/*
 * AppArmor security module
 *
 * This file contains AppArmor policy loading interface function definitions.
 *
 * Copyright 2013 Canonical Ltd.
 *
 * Fns to provide a checksum of policy that has been loaded this can be
 * compared to userspace policy compiles to check loaded policy is what
 * it should be.
 */

#include <crypto/hash.h>

#include "include/apparmor.h"
#include "include/crypto.h"

static unsigned int apparmor_hash_size;

static struct crypto_shash *apparmor_tfm;

unsigned int aa_hash_size(void)
{
	return apparmor_hash_size;
}

char *aa_calc_hash(void *data, size_t len)
{
	SHASH_DESC_ON_STACK(desc, apparmor_tfm);
	char *hash = NULL;
	int error = -ENOMEM;

	if (!apparmor_tfm)
		return NULL;

	hash = kzalloc(apparmor_hash_size, GFP_KERNEL);
	if (!hash)
		goto fail;

	desc->tfm = apparmor_tfm;

	error = crypto_shash_init(desc);
	if (error)
		goto fail;
	error = crypto_shash_update(desc, (u8 *) data, len);
	if (error)
		goto fail;
	error = crypto_shash_final(desc, hash);
	if (error)
		goto fail;

	return hash;

fail:
	kfree(hash);

	return ERR_PTR(error);
}

int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
			 size_t len)
{
	SHASH_DESC_ON_STACK(desc, apparmor_tfm);
	int error = -ENOMEM;
	__le32 le32_version = cpu_to_le32(version);

	if (!aa_g_hash_policy)
		return 0;

	if (!apparmor_tfm)
		return 0;

	profile->hash = kzalloc(apparmor_hash_size, GFP_KERNEL);
	if (!profile->hash)
		goto fail;

	desc->tfm = apparmor_tfm;

	error = crypto_shash_init(desc);
	if (error)
		goto fail;
	error = crypto_shash_update(desc, (u8 *) &le32_version, 4);
	if (error)
		goto fail;
	error = crypto_shash_update(desc, (u8 *) start, len);
	if (error)
		goto fail;
	error = crypto_shash_final(desc, profile->hash);
	if (error)
		goto fail;

	return 0;

fail:
	kfree(profile->hash);
	profile->hash = NULL;

	return error;
}

static int __init init_profile_hash(void)
{
	struct crypto_shash *tfm;

	if (!apparmor_initialized)
		return 0;

	tfm = crypto_alloc_shash("sha1", 0, 0);
	if (IS_ERR(tfm)) {
		int error = PTR_ERR(tfm);
		AA_ERROR("failed to setup profile sha1 hashing: %d\n", error);
		return error;
	}
	apparmor_tfm = tfm;
	apparmor_hash_size = crypto_shash_digestsize(apparmor_tfm);

	aa_info_message("AppArmor sha1 policy hashing enabled");

	return 0;
}

late_initcall(init_profile_hash);