| /* |
| * 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 <stdbool.h> |
| #include <cutils/properties.h> |
| |
| /* The current cryptfs version */ |
| #define CURRENT_MAJOR_VERSION 1 |
| #define CURRENT_MINOR_VERSION 3 |
| |
| #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 |
| #define SCRYPT_LEN 32 |
| |
| /* 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 /* Encryption partially completed, |
| encrypted_upto valid*/ |
| #define CRYPT_INCONSISTENT_STATE 0x4 /* Set when starting encryption, clear when |
| exit cleanly, either through success or |
| correctly marked partial encryption */ |
| #define CRYPT_DATA_CORRUPT 0x8 /* Set when encryption is fine, but the |
| underlying volume is corrupt */ |
| |
| /* Allowed values for type in the structure below */ |
| #define CRYPT_TYPE_PASSWORD 0 /* master_key is encrypted with a password |
| * Must be zero to be compatible with pre-L |
| * devices where type is always password.*/ |
| #define CRYPT_TYPE_DEFAULT 1 /* master_key is encrypted with default |
| * password */ |
| #define CRYPT_TYPE_PATTERN 2 /* master_key is encrypted with a pattern */ |
| #define CRYPT_TYPE_PIN 3 /* master_key is encrypted with a pin */ |
| #define CRYPT_TYPE_MAX_TYPE 3 /* type cannot be larger than this value */ |
| |
| #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 |
| /* Algorithms 3 & 4 deprecated before shipping outside of google, so removed */ |
| #define KDF_SCRYPT_KEYMASTER 5 |
| |
| /* Maximum allowed keymaster blob size. */ |
| #define KEYMASTER_BLOB_SIZE 2048 |
| |
| /* __le32 and __le16 defined in system/extras/ext4_utils/ext4_utils.h */ |
| #define __le8 unsigned char |
| |
| #if !defined(SHA256_DIGEST_LENGTH) |
| #define SHA256_DIGEST_LENGTH 32 |
| #endif |
| |
| 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 crypt_type; /* how master_key is encrypted. Must be a |
| * CRYPT_TYPE_XXX value */ |
| __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) */ |
| __le64 encrypted_upto; /* If we are in state CRYPT_ENCRYPTION_IN_PROGRESS and |
| we have to stop (e.g. power low) this is the last |
| encrypted 512 byte sector.*/ |
| __le8 hash_first_block[SHA256_DIGEST_LENGTH]; /* When CRYPT_ENCRYPTION_IN_PROGRESS |
| set, hash of first block, used |
| to validate before continuing*/ |
| |
| /* key_master key, used to sign the derived key which is then used to generate |
| * the intermediate key |
| * This key should be used for no other purposes! We use this key to sign unpadded |
| * data, which is acceptable but only if the key is not reused elsewhere. */ |
| __le8 keymaster_blob[KEYMASTER_BLOB_SIZE]; |
| __le32 keymaster_blob_size; |
| |
| /* Store scrypt of salted intermediate key. When decryption fails, we can |
| check if this matches, and if it does, we know that the problem is with the |
| drive, and there is no point in asking the user for more passwords. |
| |
| Note that if any part of this structure is corrupt, this will not match and |
| we will continue to believe the user entered the wrong password. In that |
| case the only solution is for the user to enter a password enough times to |
| force a wipe. |
| |
| Note also that there is no need to worry about migration. If this data is |
| wrong, we simply won't recognise a right password, and will continue to |
| prompt. On the first password change, this value will be populated and |
| then we will be OK. |
| */ |
| unsigned char scrypted_intermediate_key[SCRYPT_LEN]; |
| }; |
| |
| /* 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]; |
| }; |
| |
| #define DATA_MNT_POINT "/data" |
| |
| /* Return values for cryptfs_crypto_complete */ |
| #define CRYPTO_COMPLETE_NOT_ENCRYPTED 1 |
| #define CRYPTO_COMPLETE_ENCRYPTED 0 |
| #define CRYPTO_COMPLETE_BAD_METADATA -1 |
| #define CRYPTO_COMPLETE_PARTIAL -2 |
| #define CRYPTO_COMPLETE_INCONSISTENT -3 |
| #define CRYPTO_COMPLETE_CORRUPT -4 |
| |
| /* Return values for cryptfs_enable_inplace*() */ |
| #define ENABLE_INPLACE_OK 0 |
| #define ENABLE_INPLACE_ERR_OTHER -1 |
| #define ENABLE_INPLACE_ERR_DEV -2 /* crypto_blkdev issue */ |
| |
| /* Return values for cryptfs_getfield */ |
| #define CRYPTO_GETFIELD_OK 0 |
| #define CRYPTO_GETFIELD_ERROR_NO_FIELD -1 |
| #define CRYPTO_GETFIELD_ERROR_OTHER -2 |
| #define CRYPTO_GETFIELD_ERROR_BUF_TOO_SMALL -3 |
| |
| /* Return values for cryptfs_setfield */ |
| #define CRYPTO_SETFIELD_OK 0 |
| #define CRYPTO_SETFIELD_ERROR_OTHER -1 |
| #define CRYPTO_SETFIELD_ERROR_FIELD_TOO_LONG -2 |
| #define CRYPTO_SETFIELD_ERROR_VALUE_TOO_LONG -3 |
| |
| /* Return values for persist_del_key */ |
| #define PERSIST_DEL_KEY_OK 0 |
| #define PERSIST_DEL_KEY_ERROR_OTHER -1 |
| #define PERSIST_DEL_KEY_ERROR_NO_FIELD -2 |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| int wait_and_unmount(const char *mountpoint, bool kill); |
| |
| typedef int (*kdf_func)(const char *passwd, const unsigned char *salt, |
| unsigned char *ikey, void *params); |
| |
| int cryptfs_crypto_complete(void); |
| int cryptfs_check_passwd(char *pw); |
| int cryptfs_verify_passwd(char *newpw); |
| int cryptfs_restart(void); |
| int cryptfs_enable(char *flag, int type, char *passwd, int no_ui); |
| int cryptfs_changepw(int type, const char *newpw); |
| int cryptfs_enable_default(char *flag, int no_ui); |
| int cryptfs_setup_ext_volume(const char* label, const char* real_blkdev, |
| const unsigned char* key, int keysize, char* out_crypto_blkdev); |
| int cryptfs_revert_ext_volume(const char* label); |
| int cryptfs_enable_file(); |
| int cryptfs_getfield(const char *fieldname, char *value, int len); |
| int cryptfs_setfield(const char *fieldname, const char *value); |
| int cryptfs_mount_default_encrypted(void); |
| int cryptfs_get_password_type(void); |
| const char* cryptfs_get_password(void); |
| void cryptfs_clear_password(void); |
| |
| // Functions for file encryption to use to inherit our encryption logic |
| int cryptfs_create_default_ftr(struct crypt_mnt_ftr* ftr, int key_length); |
| int cryptfs_get_master_key(struct crypt_mnt_ftr* ftr, const char* password, |
| unsigned char* master_key); |
| int cryptfs_set_password(struct crypt_mnt_ftr* ftr, const char* password, |
| const unsigned char* master_key); |
| #ifdef __cplusplus |
| } |
| #endif |
