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f8eb8a13 JJ |
1 | /* |
2 | * AppArmor security module | |
3 | * | |
4 | * This file contains AppArmor policy loading interface function definitions. | |
5 | * | |
6 | * Copyright 2013 Canonical Ltd. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License as | |
10 | * published by the Free Software Foundation, version 2 of the | |
11 | * License. | |
12 | * | |
13 | * Fns to provide a checksum of policy that has been loaded this can be | |
14 | * compared to userspace policy compiles to check loaded policy is what | |
15 | * it should be. | |
16 | */ | |
17 | ||
18 | #include <linux/crypto.h> | |
19 | ||
20 | #include "include/apparmor.h" | |
21 | #include "include/crypto.h" | |
22 | ||
23 | static unsigned int apparmor_hash_size; | |
24 | ||
25 | static struct crypto_hash *apparmor_tfm; | |
26 | ||
27 | unsigned int aa_hash_size(void) | |
28 | { | |
29 | return apparmor_hash_size; | |
30 | } | |
31 | ||
32 | int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start, | |
33 | size_t len) | |
34 | { | |
35 | struct scatterlist sg[2]; | |
36 | struct hash_desc desc = { | |
37 | .tfm = apparmor_tfm, | |
38 | .flags = 0 | |
39 | }; | |
40 | int error = -ENOMEM; | |
41 | u32 le32_version = cpu_to_le32(version); | |
42 | ||
43 | if (!apparmor_tfm) | |
44 | return 0; | |
45 | ||
46 | sg_init_table(sg, 2); | |
47 | sg_set_buf(&sg[0], &le32_version, 4); | |
48 | sg_set_buf(&sg[1], (u8 *) start, len); | |
49 | ||
50 | profile->hash = kzalloc(apparmor_hash_size, GFP_KERNEL); | |
51 | if (!profile->hash) | |
52 | goto fail; | |
53 | ||
54 | error = crypto_hash_init(&desc); | |
55 | if (error) | |
56 | goto fail; | |
57 | error = crypto_hash_update(&desc, &sg[0], 4); | |
58 | if (error) | |
59 | goto fail; | |
60 | error = crypto_hash_update(&desc, &sg[1], len); | |
61 | if (error) | |
62 | goto fail; | |
63 | error = crypto_hash_final(&desc, profile->hash); | |
64 | if (error) | |
65 | goto fail; | |
66 | ||
67 | return 0; | |
68 | ||
69 | fail: | |
70 | kfree(profile->hash); | |
71 | profile->hash = NULL; | |
72 | ||
73 | return error; | |
74 | } | |
75 | ||
76 | static int __init init_profile_hash(void) | |
77 | { | |
78 | struct crypto_hash *tfm; | |
79 | ||
80 | if (!apparmor_initialized) | |
81 | return 0; | |
82 | ||
83 | tfm = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC); | |
84 | if (IS_ERR(tfm)) { | |
85 | int error = PTR_ERR(tfm); | |
86 | AA_ERROR("failed to setup profile sha1 hashing: %d\n", error); | |
87 | return error; | |
88 | } | |
89 | apparmor_tfm = tfm; | |
90 | apparmor_hash_size = crypto_hash_digestsize(apparmor_tfm); | |
91 | ||
92 | aa_info_message("AppArmor sha1 policy hashing enabled"); | |
93 | ||
94 | return 0; | |
95 | } | |
96 | ||
97 | late_initcall(init_profile_hash); |