/*
* Copyright (C) 2010 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.
*/
/* This structure starts 16,384 bytes before the end of a hardware
* partition that is encrypted, or in a separate partition. It's location
* is specified by a property set in init.<device>.rc.
* The structure allocates 48 bytes for a key, but the real key size is
* specified in the struct. Currently, the code is hardcoded to use 128
* bit keys.
* The fields after salt are only valid in rev 1.1 and later stuctures.
* Obviously, the filesystem does not include the last 16 kbytes
* of the partition if the crypt_mnt_ftr lives at the end of the
* partition.
*/
#include <cutils/properties.h>
/* The current cryptfs version */
#define CURRENT_MAJOR_VERSION 1
#define CURRENT_MINOR_VERSION 2
#define CRYPT_FOOTER_OFFSET 0x4000
#define CRYPT_FOOTER_TO_PERSIST_OFFSET 0x1000
#define CRYPT_PERSIST_DATA_SIZE 0x1000
#define MAX_CRYPTO_TYPE_NAME_LEN 64
#define MAX_KEY_LEN 48
#define SALT_LEN 16
/* definitions of flags in the structure below */
#define CRYPT_MNT_KEY_UNENCRYPTED 0x1 /* The key for the partition is not encrypted. */
#define CRYPT_ENCRYPTION_IN_PROGRESS 0x2 /* Set when starting encryption,
* clear when done before rebooting */
#define CRYPT_MNT_MAGIC 0xD0B5B1C4
#define PERSIST_DATA_MAGIC 0xE950CD44
#define SCRYPT_PROP "ro.crypto.scrypt_params"
#define SCRYPT_DEFAULTS { 15, 3, 1 }
/* Key Derivation Function algorithms */
#define KDF_PBKDF2 1
#define KDF_SCRYPT 2
#define __le32 unsigned int
#define __le16 unsigned short int
#define __le8 unsigned char
struct crypt_mnt_ftr {
__le32 magic; /* See above */
__le16 major_version;
__le16 minor_version;
__le32 ftr_size; /* in bytes, not including key following */
__le32 flags; /* See above */
__le32 keysize; /* in bytes */
__le32 spare1; /* ignored */
__le64 fs_size; /* Size of the encrypted fs, in 512 byte sectors */
__le32 failed_decrypt_count; /* count of # of failed attempts to decrypt and
mount, set to 0 on successful mount */
unsigned char crypto_type_name[MAX_CRYPTO_TYPE_NAME_LEN]; /* The type of encryption
needed to decrypt this
partition, null terminated */
__le32 spare2; /* ignored */
unsigned char master_key[MAX_KEY_LEN]; /* The encrypted key for decrypting the filesystem */
unsigned char salt[SALT_LEN]; /* The salt used for this encryption */
__le64 persist_data_offset[2]; /* Absolute offset to both copies of crypt_persist_data
* on device with that info, either the footer of the
* real_blkdevice or the metadata partition. */
__le32 persist_data_size; /* The number of bytes allocated to each copy of the
* persistent data table*/
__le8 kdf_type; /* The key derivation function used. */
/* scrypt parameters. See www.tarsnap.com/scrypt/scrypt.pdf */
__le8 N_factor; /* (1 << N) */
__le8 r_factor; /* (1 << r) */
__le8 p_factor; /* (1 << p) */
};
/* Persistant data that should be available before decryption.
* Things like airplane mode, locale and timezone are kept
* here and can be retrieved by the CryptKeeper UI to properly
* configure the phone before asking for the password
* This is only valid if the major and minor version above
* is set to 1.1 or higher.
*
* This is a 4K structure. There are 2 copies, and the code alternates
* writing one and then clearing the previous one. The reading
* code reads the first valid copy it finds, based on the magic number.
* The absolute offset to the first of the two copies is kept in rev 1.1
* and higher crypt_mnt_ftr structures.
*/
struct crypt_persist_entry {
char key[PROPERTY_KEY_MAX];
char val[PROPERTY_VALUE_MAX];
};
/* Should be exactly 4K in size */
struct crypt_persist_data {
__le32 persist_magic;
__le32 persist_valid_entries;
__le32 persist_spare[30];
struct crypt_persist_entry persist_entry[0];
};
struct volume_info {
unsigned int size;
unsigned int flags;
struct crypt_mnt_ftr crypt_ftr;
char mnt_point[256];
char blk_dev[256];
char crypto_blkdev[256];
char label[256];
};
#define VOL_NONREMOVABLE 0x1
#define VOL_ENCRYPTABLE 0x2
#define VOL_PRIMARY 0x4
#define VOL_PROVIDES_ASEC 0x8
#ifdef __cplusplus
extern "C" {
#endif
typedef void (*kdf_func)(char *passwd, unsigned char *salt, unsigned char *ikey, void *params);
int cryptfs_crypto_complete(void);
int cryptfs_check_footer(void);
int cryptfs_check_passwd(char *pw);
int cryptfs_verify_passwd(char *newpw);
int cryptfs_restart(void);
int cryptfs_enable(char *flag, char *passwd);
int cryptfs_changepw(char *newpw);
int cryptfs_setup_volume(const char *label, int major, int minor,
char *crypto_dev_path, unsigned int max_pathlen,
int *new_major, int *new_minor);
int cryptfs_revert_volume(const char *label);
int cryptfs_getfield(char *fieldname, char *value, int len);
int cryptfs_setfield(char *fieldname, char *value);
#ifdef __cplusplus
}
#endif
