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linux-next/security/apparmor/crypto.c
John Johansen 5ac8c355ae apparmor: allow introspecting the loaded policy pre internal transform
Store loaded policy and allow introspecting it through apparmorfs. This
has several uses from debugging, policy validation, and policy checkpoint
and restore for containers.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2017-01-16 01:18:42 -08:00

136 lines
2.7 KiB
C

/*
* AppArmor security module
*
* This file contains AppArmor policy loading interface function definitions.
*
* Copyright 2013 Canonical Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
* 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)
{
struct {
struct shash_desc shash;
char ctx[crypto_shash_descsize(apparmor_tfm)];
} desc;
char *hash = NULL;
int error = -ENOMEM;
if (!apparmor_tfm)
return NULL;
hash = kzalloc(apparmor_hash_size, GFP_KERNEL);
if (!hash)
goto fail;
desc.shash.tfm = apparmor_tfm;
desc.shash.flags = 0;
error = crypto_shash_init(&desc.shash);
if (error)
goto fail;
error = crypto_shash_update(&desc.shash, (u8 *) data, len);
if (error)
goto fail;
error = crypto_shash_final(&desc.shash, 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)
{
struct {
struct shash_desc shash;
char ctx[crypto_shash_descsize(apparmor_tfm)];
} desc;
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.shash.tfm = apparmor_tfm;
desc.shash.flags = 0;
error = crypto_shash_init(&desc.shash);
if (error)
goto fail;
error = crypto_shash_update(&desc.shash, (u8 *) &le32_version, 4);
if (error)
goto fail;
error = crypto_shash_update(&desc.shash, (u8 *) start, len);
if (error)
goto fail;
error = crypto_shash_final(&desc.shash, 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, CRYPTO_ALG_ASYNC);
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);