| John Johansen | f8eb8a1 | 2013-08-14 11:27:36 -0700 | [diff] [blame] | 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); |