crypto.c

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * AppArmor security module
 4 *
 5 * This file contains AppArmor policy loading interface function definitions.
 6 *
 7 * Copyright 2013 Canonical Ltd.
 8 *
 9 * Fns to provide a checksum of policy that has been loaded this can be
10 * compared to userspace policy compiles to check loaded policy is what
11 * it should be.
12 */
13
14#include <crypto/sha2.h>
15
16#include "include/apparmor.h"
17#include "include/crypto.h"
18
19unsigned int aa_hash_size(void)
20{
21	return SHA256_DIGEST_SIZE;
22}
23
24char *aa_calc_hash(void *data, size_t len)
25{
26	char *hash;
27
28	hash = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
29	if (!hash)
30		return ERR_PTR(-ENOMEM);
31
32	sha256(data, len, hash);
33	return hash;
34}
35
36int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
37			 size_t len)
38{
39	struct sha256_ctx sctx;
40	__le32 le32_version = cpu_to_le32(version);
41
42	if (!aa_g_hash_policy)
43		return 0;
44
45	profile->hash = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
46	if (!profile->hash)
47		return -ENOMEM;
48
49	sha256_init(&sctx);
50	sha256_update(&sctx, (u8 *)&le32_version, 4);
51	sha256_update(&sctx, (u8 *)start, len);
52	sha256_final(&sctx, profile->hash);
53	return 0;
54}
55
56int __init init_profile_hash(void)
57{
58	if (apparmor_initialized)
59		aa_info_message("AppArmor sha256 policy hashing enabled");
60	return 0;
61}