fscrypt_policy.h

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _FS_CRYPT_H_
#define _FS_CRYPT_H_

#include <sys/cdefs.h>
#include <stdbool.h>
#include <stdint.h>
#include <cutils/multiuser.h>
#include <linux/fs.h>

__BEGIN_DECLS

#define FS_KEY_DESCRIPTOR_SIZE_HEX (2 * FS_KEY_DESCRIPTOR_SIZE + 1)
#define FSCRYPT_KEY_IDENTIFIER_SIZE_HEX ((2 * FSCRYPT_KEY_IDENTIFIER_SIZE) + 1)

#define USER_CE_FSCRYPT_POLICY           "CE"
#define USER_DE_FSCRYPT_POLICY           "DE"
#define SYSTEM_DE_FSCRYPT_POLICY         "DK"

#define SYSTEM_DE_KEY                     "DK"
#define USER_CE_KEY                       "C"
#define USER_DE_KEY                       "D"

/* modes not supported by upstream kernel, so not in <linux/fs.h> */
#define FS_ENCRYPTION_MODE_AES_256_HEH      126
#define FS_ENCRYPTION_MODE_PRIVATE          127

/* new definition, not yet in Bionic's <linux/fs.h> */
#ifndef FS_ENCRYPTION_MODE_ADIANTUM
#define FS_ENCRYPTION_MODE_ADIANTUM         9
#endif

/* new definition, not yet in Bionic's <linux/fs.h> */
#ifndef FS_POLICY_FLAG_DIRECT_KEY
#define FS_POLICY_FLAG_DIRECT_KEY           0x4
#endif

#define HEX_LOOKUP "0123456789abcdef"

bool fscrypt_set_mode();

#undef fscrypt_policy
typedef union fscrypt_policy {
	uint8_t version;
	struct fscrypt_policy_v1 v1;
	struct fscrypt_policy_v2 v2;
} fscrypt_policy;

bool lookup_ref_key(fscrypt_policy *fep, uint8_t* policy_type);

bool lookup_ref_tar(fscrypt_policy *fep, uint8_t *policy);

bool fscrypt_policy_get_struct(const char *directory, fscrypt_policy *fep);

bool fscrypt_policy_set_struct(const char *directory, fscrypt_policy  *fep);

void bytes_to_hex(const uint8_t *bytes, size_t num_bytes, char *hex);

uint8_t* get_policy_descriptor(fscrypt_policy* fep);

void* get_policy(const fscrypt_policy* fep);

uint8_t get_policy_size(fscrypt_policy* fep, bool hex);

int fscrypt_policy_size(const fscrypt_policy *policy);

void get_policy_content(fscrypt_policy* fep, char* content);
__END_DECLS

#endif // _FS_CRYPT_H_