1#ifndef _LINUX_ECRYPTFS_H
2#define _LINUX_ECRYPTFS_H
3
4/* Version verification for shared data structures w/ userspace */
5#define ECRYPTFS_VERSION_MAJOR 0x00
6#define ECRYPTFS_VERSION_MINOR 0x04
7#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x03
8/* These flags indicate which features are supported by the kernel
9 * module; userspace tools such as the mount helper read the feature
10 * bits from a sysfs handle in order to determine how to behave. */
11#define ECRYPTFS_VERSIONING_PASSPHRASE            0x00000001
12#define ECRYPTFS_VERSIONING_PUBKEY                0x00000002
13#define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004
14#define ECRYPTFS_VERSIONING_POLICY                0x00000008
15#define ECRYPTFS_VERSIONING_XATTR                 0x00000010
16#define ECRYPTFS_VERSIONING_MULTKEY               0x00000020
17#define ECRYPTFS_VERSIONING_DEVMISC               0x00000040
18#define ECRYPTFS_VERSIONING_HMAC                  0x00000080
19#define ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION   0x00000100
20#define ECRYPTFS_VERSIONING_GCM                   0x00000200
21#define ECRYPTFS_MAX_PASSWORD_LENGTH 64
22#define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
23#define ECRYPTFS_SALT_SIZE 8
24#define ECRYPTFS_SALT_SIZE_HEX (ECRYPTFS_SALT_SIZE*2)
25/* The original signature size is only for what is stored on disk; all
26 * in-memory representations are expanded hex, so it better adapted to
27 * be passed around or referenced on the command line */
28#define ECRYPTFS_SIG_SIZE 8
29#define ECRYPTFS_SIG_SIZE_HEX (ECRYPTFS_SIG_SIZE*2)
30#define ECRYPTFS_PASSWORD_SIG_SIZE ECRYPTFS_SIG_SIZE_HEX
31#define ECRYPTFS_MAX_KEY_BYTES 64
32#define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512
33#define ECRYPTFS_FILE_VERSION 0x03
34#define ECRYPTFS_MAX_PKI_NAME_BYTES 16
35
36#define RFC2440_CIPHER_DES3_EDE 0x02
37#define RFC2440_CIPHER_CAST_5 0x03
38#define RFC2440_CIPHER_BLOWFISH 0x04
39#define RFC2440_CIPHER_AES_128 0x07
40#define RFC2440_CIPHER_AES_192 0x08
41#define RFC2440_CIPHER_AES_256 0x09
42#define RFC2440_CIPHER_TWOFISH 0x0a
43#define RFC2440_CIPHER_CAST_6 0x0b
44
45#define RFC2440_CIPHER_RSA 0x01
46
47/**
48 * For convenience, we may need to pass around the encrypted session
49 * key between kernel and userspace because the authentication token
50 * may not be extractable.  For example, the TPM may not release the
51 * private key, instead requiring the encrypted data and returning the
52 * decrypted data.
53 */
54struct ecryptfs_session_key {
55#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT 0x00000001
56#define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT 0x00000002
57#define ECRYPTFS_CONTAINS_DECRYPTED_KEY 0x00000004
58#define ECRYPTFS_CONTAINS_ENCRYPTED_KEY 0x00000008
59	u32 flags;
60	u32 encrypted_key_size;
61	u32 decrypted_key_size;
62	u8 encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
63	u8 decrypted_key[ECRYPTFS_MAX_KEY_BYTES];
64};
65
66struct ecryptfs_password {
67	u32 password_bytes;
68	s32 hash_algo;
69	u32 hash_iterations;
70	u32 session_key_encryption_key_bytes;
71#define ECRYPTFS_PERSISTENT_PASSWORD 0x01
72#define ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET 0x02
73	u32 flags;
74	/* Iterated-hash concatenation of salt and passphrase */
75	u8 session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
76	u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
77	/* Always in expanded hex */
78	u8 salt[ECRYPTFS_SALT_SIZE];
79};
80
81enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY};
82
83struct ecryptfs_private_key {
84	u32 key_size;
85	u32 data_len;
86	u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
87	char pki_type[ECRYPTFS_MAX_PKI_NAME_BYTES + 1];
88	u8 data[];
89};
90
91/* May be a password or a private key */
92struct ecryptfs_auth_tok {
93	u16 version; /* 8-bit major and 8-bit minor */
94	u16 token_type;
95#define ECRYPTFS_ENCRYPT_ONLY 0x00000001
96	u32 flags;
97	struct ecryptfs_session_key session_key;
98	u8 reserved[32];
99	union {
100		struct ecryptfs_password password;
101		struct ecryptfs_private_key private_key;
102	} token;
103} __attribute__ ((packed));
104
105#endif /* _LINUX_ECRYPTFS_H */
106