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|
/**
* eCryptfs: Linux filesystem encryption layer
* Kernel declarations.
*
* Copyright (C) 1997-2003 Erez Zadok
* Copyright (C) 2001-2003 Stony Brook University
* Copyright (C) 2004-2008 International Business Machines Corp.
* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
* Trevor S. Highland <trevor.highland@gmail.com>
* Tyler Hicks <tyhicks@ou.edu>
*
* 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; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#ifndef ECRYPTFS_KERNEL_H
#define ECRYPTFS_KERNEL_H
#include <keys/user-type.h>
#include <linux/fs.h>
#include <linux/fs_stack.h>
#include <linux/namei.h>
#include <linux/scatterlist.h>
#include <linux/hash.h>
#include <linux/nsproxy.h>
#include <linux/backing-dev.h>
/* Version verification for shared data structures w/ userspace */
#define ECRYPTFS_VERSION_MAJOR 0x00
#define ECRYPTFS_VERSION_MINOR 0x04
#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x03
/* These flags indicate which features are supported by the kernel
* module; userspace tools such as the mount helper read
* ECRYPTFS_VERSIONING_MASK from a sysfs handle in order to determine
* how to behave. */
#define ECRYPTFS_VERSIONING_PASSPHRASE 0x00000001
#define ECRYPTFS_VERSIONING_PUBKEY 0x00000002
#define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004
#define ECRYPTFS_VERSIONING_POLICY 0x00000008
#define ECRYPTFS_VERSIONING_XATTR 0x00000010
#define ECRYPTFS_VERSIONING_MULTKEY 0x00000020
#define ECRYPTFS_VERSIONING_DEVMISC 0x00000040
#define ECRYPTFS_VERSIONING_HMAC 0x00000080
#define ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION 0x00000100
#define ECRYPTFS_VERSIONING_GCM 0x00000200
#define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
| ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH \
| ECRYPTFS_VERSIONING_PUBKEY \
| ECRYPTFS_VERSIONING_XATTR \
| ECRYPTFS_VERSIONING_MULTKEY \
| ECRYPTFS_VERSIONING_DEVMISC \
| ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION)
#define ECRYPTFS_MAX_PASSWORD_LENGTH 64
#define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
#define ECRYPTFS_SALT_SIZE 8
#define ECRYPTFS_SALT_SIZE_HEX (ECRYPTFS_SALT_SIZE*2)
/* The original signature size is only for what is stored on disk; all
* in-memory representations are expanded hex, so it better adapted to
* be passed around or referenced on the command line */
#define ECRYPTFS_SIG_SIZE 8
#define ECRYPTFS_SIG_SIZE_HEX (ECRYPTFS_SIG_SIZE*2)
#define ECRYPTFS_PASSWORD_SIG_SIZE ECRYPTFS_SIG_SIZE_HEX
#define ECRYPTFS_MAX_KEY_BYTES 64
#define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512
#define ECRYPTFS_DEFAULT_IV_BYTES 16
#define ECRYPTFS_FILE_VERSION 0x03
#define ECRYPTFS_DEFAULT_EXTENT_SIZE 4096
#define ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE 8192
#define ECRYPTFS_DEFAULT_MSG_CTX_ELEMS 32
#define ECRYPTFS_DEFAULT_SEND_TIMEOUT HZ
#define ECRYPTFS_MAX_MSG_CTX_TTL (HZ*3)
#define ECRYPTFS_MAX_PKI_NAME_BYTES 16
#define ECRYPTFS_DEFAULT_NUM_USERS 4
#define ECRYPTFS_MAX_NUM_USERS 32768
#define ECRYPTFS_XATTR_NAME "user.ecryptfs"
#define RFC2440_CIPHER_DES3_EDE 0x02
#define RFC2440_CIPHER_CAST_5 0x03
#define RFC2440_CIPHER_BLOWFISH 0x04
#define RFC2440_CIPHER_AES_128 0x07
#define RFC2440_CIPHER_AES_192 0x08
#define RFC2440_CIPHER_AES_256 0x09
#define RFC2440_CIPHER_TWOFISH 0x0a
#define RFC2440_CIPHER_CAST_6 0x0b
#define RFC2440_CIPHER_RSA 0x01
/**
* For convenience, we may need to pass around the encrypted session
* key between kernel and userspace because the authentication token
* may not be extractable. For example, the TPM may not release the
* private key, instead requiring the encrypted data and returning the
* decrypted data.
*/
struct ecryptfs_session_key {
#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT 0x00000001
#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT 0x00000002
#define ECRYPTFS_CONTAINS_DECRYPTED_KEY 0x00000004
#define ECRYPTFS_CONTAINS_ENCRYPTED_KEY 0x00000008
u32 flags;
u32 encrypted_key_size;
u32 decrypted_key_size;
u8 encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
u8 decrypted_key[ECRYPTFS_MAX_KEY_BYTES];
};
struct ecryptfs_password {
u32 password_bytes;
s32 hash_algo;
u32 hash_iterations;
u32 session_key_encryption_key_bytes;
#define ECRYPTFS_PERSISTENT_PASSWORD 0x01
#define ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET 0x02
u32 flags;
/* Iterated-hash concatenation of salt and passphrase */
u8 session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
/* Always in expanded hex */
u8 salt[ECRYPTFS_SALT_SIZE];
};
enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY};
struct ecryptfs_private_key {
u32 key_size;
u32 data_len;
u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
char pki_type[ECRYPTFS_MAX_PKI_NAME_BYTES + 1];
u8 data[];
};
/* May be a password or a private key */
struct ecryptfs_auth_tok {
u16 version; /* 8-bit major and 8-bit minor */
u16 token_type;
#define ECRYPTFS_ENCRYPT_ONLY 0x00000001
u32 flags;
struct ecryptfs_session_key session_key;
u8 reserved[32];
union {
struct ecryptfs_password password;
struct ecryptfs_private_key private_key;
} token;
} __attribute__ ((packed));
void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok);
extern void ecryptfs_to_hex(char *dst, char *src, size_t src_size);
extern void ecryptfs_from_hex(char *dst, char *src, int dst_size);
struct ecryptfs_key_record {
unsigned char type;
size_t enc_key_size;
unsigned char sig[ECRYPTFS_SIG_SIZE];
unsigned char enc_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
};
struct ecryptfs_auth_tok_list {
struct ecryptfs_auth_tok *auth_tok;
struct list_head list;
};
struct ecryptfs_crypt_stat;
struct ecryptfs_mount_crypt_stat;
struct ecryptfs_page_crypt_context {
struct page *page;
#define ECRYPTFS_PREPARE_COMMIT_MODE 0
#define ECRYPTFS_WRITEPAGE_MODE 1
unsigned int mode;
union {
struct file *lower_file;
struct writeback_control *wbc;
} param;
};
static inline struct ecryptfs_auth_tok *
ecryptfs_get_key_payload_data(struct key *key)
{
return (struct ecryptfs_auth_tok *)
(((struct user_key_payload*)key->payload.data)->data);
}
#define ECRYPTFS_MAX_KEYSET_SIZE 1024
#define ECRYPTFS_MAX_CIPHER_NAME_SIZE 32
#define ECRYPTFS_MAX_NUM_ENC_KEYS 64
#define ECRYPTFS_MAX_IV_BYTES 16 /* 128 bits */
#define ECRYPTFS_SALT_BYTES 2
#define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5
#define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8 /* 4*2 */
#define ECRYPTFS_FILE_SIZE_BYTES (sizeof(u64))
#define ECRYPTFS_SIZE_AND_MARKER_BYTES (ECRYPTFS_FILE_SIZE_BYTES \
+ MAGIC_ECRYPTFS_MARKER_SIZE_BYTES)
#define ECRYPTFS_DEFAULT_CIPHER "aes"
#define ECRYPTFS_DEFAULT_KEY_BYTES 16
#define ECRYPTFS_DEFAULT_HASH "md5"
#define ECRYPTFS_TAG_70_DIGEST ECRYPTFS_DEFAULT_HASH
#define ECRYPTFS_TAG_1_PACKET_TYPE 0x01
#define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C
#define ECRYPTFS_TAG_11_PACKET_TYPE 0xED
#define ECRYPTFS_TAG_64_PACKET_TYPE 0x40
#define ECRYPTFS_TAG_65_PACKET_TYPE 0x41
#define ECRYPTFS_TAG_66_PACKET_TYPE 0x42
#define ECRYPTFS_TAG_67_PACKET_TYPE 0x43
#define ECRYPTFS_TAG_70_PACKET_TYPE 0x46 /* FNEK-encrypted filename
* as dentry name */
#define ECRYPTFS_TAG_71_PACKET_TYPE 0x47 /* FNEK-encrypted filename in
* metadata */
#define ECRYPTFS_TAG_72_PACKET_TYPE 0x48 /* FEK-encrypted filename as
* dentry name */
#define ECRYPTFS_TAG_73_PACKET_TYPE 0x49 /* FEK-encrypted filename as
* metadata */
/* Constraint: ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES >=
* ECRYPTFS_MAX_IV_BYTES */
#define ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 16
#define ECRYPTFS_NON_NULL 0x42 /* A reasonable substitute for NULL */
#define MD5_DIGEST_SIZE 16
#define ECRYPTFS_TAG_70_DIGEST_SIZE MD5_DIGEST_SIZE
#define ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX "ECRYPTFS_FEK_ENCRYPTED."
#define ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE 23
#define ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX "ECRYPTFS_FNEK_ENCRYPTED."
#define ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE 24
#define ECRYPTFS_ENCRYPTED_DENTRY_NAME_LEN (18 + 1 + 4 + 1 + 32)
struct ecryptfs_key_sig {
struct list_head crypt_stat_list;
char keysig[ECRYPTFS_SIG_SIZE_HEX + 1];
};
struct ecryptfs_filename {
struct list_head crypt_stat_list;
#define ECRYPTFS_FILENAME_CONTAINS_DECRYPTED 0x00000001
u32 flags;
u32 seq_no;
char *filename;
char *encrypted_filename;
size_t filename_size;
size_t encrypted_filename_size;
char fnek_sig[ECRYPTFS_SIG_SIZE_HEX];
char dentry_name[ECRYPTFS_ENCRYPTED_DENTRY_NAME_LEN + 1];
};
/**
* This is the primary struct associated with each encrypted file.
*
* TODO: cache align/pack?
*/
struct ecryptfs_crypt_stat {
#define ECRYPTFS_STRUCT_INITIALIZED 0x00000001
#define ECRYPTFS_POLICY_APPLIED 0x00000002
#define ECRYPTFS_ENCRYPTED 0x00000004
#define ECRYPTFS_SECURITY_WARNING 0x00000008
#define ECRYPTFS_ENABLE_HMAC 0x00000010
#define ECRYPTFS_ENCRYPT_IV_PAGES 0x00000020
#define ECRYPTFS_KEY_VALID 0x00000040
#define ECRYPTFS_METADATA_IN_XATTR 0x00000080
#define ECRYPTFS_VIEW_AS_ENCRYPTED 0x00000100
#define ECRYPTFS_KEY_SET 0x00000200
#define ECRYPTFS_ENCRYPT_FILENAMES 0x00000400
#define ECRYPTFS_ENCFN_USE_MOUNT_FNEK 0x00000800
#define ECRYPTFS_ENCFN_USE_FEK 0x00001000
#define ECRYPTFS_UNLINK_SIGS 0x00002000
#define ECRYPTFS_I_SIZE_INITIALIZED 0x00004000
u32 flags;
unsigned int file_version;
size_t iv_bytes;
size_t metadata_size;
size_t extent_size; /* Data extent size; default is 4096 */
size_t key_size;
size_t extent_shift;
unsigned int extent_mask;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
struct crypto_blkcipher *tfm;
struct crypto_hash *hash_tfm; /* Crypto context for generating
* the initialization vectors */
unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
unsigned char key[ECRYPTFS_MAX_KEY_BYTES];
unsigned char root_iv[ECRYPTFS_MAX_IV_BYTES];
struct list_head keysig_list;
struct mutex keysig_list_mutex;
struct mutex cs_tfm_mutex;
struct mutex cs_hash_tfm_mutex;
struct mutex cs_mutex;
};
/* inode private data. */
struct
|