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b886d83c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
f8eb8a13 JJ |
2 | /* |
3 | * AppArmor security module | |
4 | * | |
5 | * This file contains AppArmor policy loading interface function definitions. | |
6 | * | |
7 | * Copyright 2013 Canonical Ltd. | |
8 | * | |
f8eb8a13 JJ |
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 | ||
71ac7f62 | 14 | #include <crypto/hash.h> |
f8eb8a13 JJ |
15 | |
16 | #include "include/apparmor.h" | |
17 | #include "include/crypto.h" | |
18 | ||
19 | static unsigned int apparmor_hash_size; | |
20 | ||
71ac7f62 | 21 | static struct crypto_shash *apparmor_tfm; |
f8eb8a13 JJ |
22 | |
23 | unsigned int aa_hash_size(void) | |
24 | { | |
25 | return apparmor_hash_size; | |
26 | } | |
27 | ||
5ac8c355 JJ |
28 | char *aa_calc_hash(void *data, size_t len) |
29 | { | |
9814448d | 30 | SHASH_DESC_ON_STACK(desc, apparmor_tfm); |
5ac8c355 JJ |
31 | char *hash = NULL; |
32 | int error = -ENOMEM; | |
33 | ||
34 | if (!apparmor_tfm) | |
35 | return NULL; | |
36 | ||
37 | hash = kzalloc(apparmor_hash_size, GFP_KERNEL); | |
38 | if (!hash) | |
39 | goto fail; | |
40 | ||
9814448d | 41 | desc->tfm = apparmor_tfm; |
5ac8c355 | 42 | |
9814448d | 43 | error = crypto_shash_init(desc); |
5ac8c355 JJ |
44 | if (error) |
45 | goto fail; | |
9814448d | 46 | error = crypto_shash_update(desc, (u8 *) data, len); |
5ac8c355 JJ |
47 | if (error) |
48 | goto fail; | |
9814448d | 49 | error = crypto_shash_final(desc, hash); |
5ac8c355 JJ |
50 | if (error) |
51 | goto fail; | |
52 | ||
53 | return hash; | |
54 | ||
55 | fail: | |
56 | kfree(hash); | |
57 | ||
58 | return ERR_PTR(error); | |
59 | } | |
60 | ||
f8eb8a13 JJ |
61 | int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start, |
62 | size_t len) | |
63 | { | |
9814448d | 64 | SHASH_DESC_ON_STACK(desc, apparmor_tfm); |
f8eb8a13 | 65 | int error = -ENOMEM; |
5ac8c355 | 66 | __le32 le32_version = cpu_to_le32(version); |
f8eb8a13 | 67 | |
7616ac70 AB |
68 | if (!aa_g_hash_policy) |
69 | return 0; | |
70 | ||
f8eb8a13 JJ |
71 | if (!apparmor_tfm) |
72 | return 0; | |
73 | ||
f8eb8a13 JJ |
74 | profile->hash = kzalloc(apparmor_hash_size, GFP_KERNEL); |
75 | if (!profile->hash) | |
76 | goto fail; | |
77 | ||
9814448d | 78 | desc->tfm = apparmor_tfm; |
71ac7f62 | 79 | |
9814448d | 80 | error = crypto_shash_init(desc); |
f8eb8a13 JJ |
81 | if (error) |
82 | goto fail; | |
9814448d | 83 | error = crypto_shash_update(desc, (u8 *) &le32_version, 4); |
f8eb8a13 JJ |
84 | if (error) |
85 | goto fail; | |
9814448d | 86 | error = crypto_shash_update(desc, (u8 *) start, len); |
f8eb8a13 JJ |
87 | if (error) |
88 | goto fail; | |
9814448d | 89 | error = crypto_shash_final(desc, profile->hash); |
f8eb8a13 JJ |
90 | if (error) |
91 | goto fail; | |
92 | ||
93 | return 0; | |
94 | ||
95 | fail: | |
96 | kfree(profile->hash); | |
97 | profile->hash = NULL; | |
98 | ||
99 | return error; | |
100 | } | |
101 | ||
102 | static int __init init_profile_hash(void) | |
103 | { | |
71ac7f62 | 104 | struct crypto_shash *tfm; |
f8eb8a13 JJ |
105 | |
106 | if (!apparmor_initialized) | |
107 | return 0; | |
108 | ||
3d234b33 | 109 | tfm = crypto_alloc_shash("sha1", 0, 0); |
f8eb8a13 JJ |
110 | if (IS_ERR(tfm)) { |
111 | int error = PTR_ERR(tfm); | |
112 | AA_ERROR("failed to setup profile sha1 hashing: %d\n", error); | |
113 | return error; | |
114 | } | |
115 | apparmor_tfm = tfm; | |
71ac7f62 | 116 | apparmor_hash_size = crypto_shash_digestsize(apparmor_tfm); |
f8eb8a13 JJ |
117 | |
118 | aa_info_message("AppArmor sha1 policy hashing enabled"); | |
119 | ||
120 | return 0; | |
121 | } | |
122 | ||
123 | late_initcall(init_profile_hash); |