152 lines
5.4 KiB
C
152 lines
5.4 KiB
C
#ifndef _LINUX_ECRYPTFS_H
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#define _LINUX_ECRYPTFS_H
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struct inode;
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struct page;
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/* Version verification for shared data structures w/ userspace */
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#define ECRYPTFS_VERSION_MAJOR 0x00
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#define ECRYPTFS_VERSION_MINOR 0x04
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#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x03
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/* These flags indicate which features are supported by the kernel
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* module; userspace tools such as the mount helper read the feature
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* bits from a sysfs handle in order to determine how to behave. */
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#define ECRYPTFS_VERSIONING_PASSPHRASE 0x00000001
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#define ECRYPTFS_VERSIONING_PUBKEY 0x00000002
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#define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004
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#define ECRYPTFS_VERSIONING_POLICY 0x00000008
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#define ECRYPTFS_VERSIONING_XATTR 0x00000010
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#define ECRYPTFS_VERSIONING_MULTKEY 0x00000020
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#define ECRYPTFS_VERSIONING_DEVMISC 0x00000040
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#define ECRYPTFS_VERSIONING_HMAC 0x00000080
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#define ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION 0x00000100
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#define ECRYPTFS_VERSIONING_GCM 0x00000200
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#define ECRYPTFS_MAX_PASSWORD_LENGTH 64
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#define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
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#define ECRYPTFS_SALT_SIZE 8
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#define ECRYPTFS_SALT_SIZE_HEX (ECRYPTFS_SALT_SIZE*2)
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/* The original signature size is only for what is stored on disk; all
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* in-memory representations are expanded hex, so it better adapted to
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* be passed around or referenced on the command line */
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#define ECRYPTFS_SIG_SIZE 8
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#define ECRYPTFS_SIG_SIZE_HEX (ECRYPTFS_SIG_SIZE*2)
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#define ECRYPTFS_PASSWORD_SIG_SIZE ECRYPTFS_SIG_SIZE_HEX
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#define ECRYPTFS_MAX_KEY_BYTES 64
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#define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512
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#define ECRYPTFS_FILE_VERSION 0x03
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#define ECRYPTFS_MAX_PKI_NAME_BYTES 16
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#define RFC2440_CIPHER_DES3_EDE 0x02
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#define RFC2440_CIPHER_CAST_5 0x03
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#define RFC2440_CIPHER_BLOWFISH 0x04
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#define RFC2440_CIPHER_AES_128 0x07
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#define RFC2440_CIPHER_AES_192 0x08
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#define RFC2440_CIPHER_AES_256 0x09
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#define RFC2440_CIPHER_TWOFISH 0x0a
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#define RFC2440_CIPHER_CAST_6 0x0b
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#define RFC2440_CIPHER_AES_XTS_256 0x0c
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#define RFC2440_CIPHER_RSA 0x01
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/**
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* For convenience, we may need to pass around the encrypted session
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* key between kernel and userspace because the authentication token
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* may not be extractable. For example, the TPM may not release the
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* private key, instead requiring the encrypted data and returning the
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* decrypted data.
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*/
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struct ecryptfs_session_key {
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#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT 0x00000001
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#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT 0x00000002
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#define ECRYPTFS_CONTAINS_DECRYPTED_KEY 0x00000004
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#define ECRYPTFS_CONTAINS_ENCRYPTED_KEY 0x00000008
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u32 flags;
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u32 encrypted_key_size;
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u32 decrypted_key_size;
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u8 encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
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u8 decrypted_key[ECRYPTFS_MAX_KEY_BYTES];
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};
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struct ecryptfs_password {
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u32 password_bytes;
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s32 hash_algo;
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u32 hash_iterations;
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u32 session_key_encryption_key_bytes;
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#define ECRYPTFS_PERSISTENT_PASSWORD 0x01
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#define ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET 0x02
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u32 flags;
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/* Iterated-hash concatenation of salt and passphrase */
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u8 session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
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u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
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/* Always in expanded hex */
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u8 salt[ECRYPTFS_SALT_SIZE];
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};
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enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY};
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struct ecryptfs_private_key {
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u32 key_size;
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u32 data_len;
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u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
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char pki_type[ECRYPTFS_MAX_PKI_NAME_BYTES + 1];
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u8 data[];
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};
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/* May be a password or a private key */
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struct ecryptfs_auth_tok {
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u16 version; /* 8-bit major and 8-bit minor */
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u16 token_type;
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#define ECRYPTFS_ENCRYPT_ONLY 0x00000001
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u32 flags;
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struct ecryptfs_session_key session_key;
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u8 reserved[32];
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union {
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struct ecryptfs_password password;
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struct ecryptfs_private_key private_key;
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} token;
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} __attribute__ ((packed));
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#define ECRYPTFS_INVALID_EVENTS_HANDLE -1
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/**
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* ecryptfs_events struct represents a partial interface
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* towards ecryptfs module. If registered to ecryptfs events,
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* one can receive push notifications.
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* A first callback received from ecryptfs will probably be
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* about file opening (open_cb),
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* in which ecryptfs passes its ecryptfs_data for future usage.
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* This data represents a file and must be passed in every query functions
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* such as ecryptfs_get_key_size(), ecryptfs_get_cipher() etc.
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*/
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struct ecryptfs_events {
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bool (*is_cipher_supported_cb)(const char *cipher);
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void (*open_cb)(struct inode *inode, void *ecrytpfs_data);
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void (*release_cb)(struct inode *inode);
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int (*encrypt_cb)(struct page *in_page, struct page *out_page,
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struct inode *inode, unsigned long extent_offset);
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int (*decrypt_cb)(struct page *in_page, struct page *out_page,
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struct inode *inode, unsigned long extent_offset);
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bool (*is_hw_crypt_cb)(void);
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size_t (*get_salt_key_size_cb)(const char *cipher);
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};
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int ecryptfs_register_to_events(struct ecryptfs_events *ops);
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int ecryptfs_unregister_from_events(int user_handle);
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const unsigned char *ecryptfs_get_key(void *ecrytpfs_data);
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size_t ecryptfs_get_key_size(void *ecrytpfs_data);
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const unsigned char *ecryptfs_get_salt(void *ecrytpfs_data);
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size_t ecryptfs_get_salt_size(void *ecrytpfs_data);
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const unsigned char *ecryptfs_get_cipher(void *ecrytpfs_data);
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bool ecryptfs_is_page_in_metadata(void *ecrytpfs_data, pgoff_t offset);
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bool ecryptfs_is_data_equal(void *ecrytpfs_data1, void *ecrytpfs_data2);
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#endif /* _LINUX_ECRYPTFS_H */
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