include/linux/ecryptfs.h

   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
  10  * ECRYPTFS_VERSIONING_MASK from a sysfs handle in order to determine
  11  * how to behave. */
  12 #define ECRYPTFS_VERSIONING_PASSPHRASE            0x00000001
  13 #define ECRYPTFS_VERSIONING_PUBKEY                0x00000002
  14 #define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004
  15 #define ECRYPTFS_VERSIONING_POLICY                0x00000008
  16 #define ECRYPTFS_VERSIONING_XATTR                 0x00000010
  17 #define ECRYPTFS_VERSIONING_MULTKEY               0x00000020
  18 #define ECRYPTFS_VERSIONING_DEVMISC               0x00000040
  19 #define ECRYPTFS_VERSIONING_HMAC                  0x00000080
  20 #define ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION   0x00000100
  21 #define ECRYPTFS_VERSIONING_GCM                   0x00000200
  22 #define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
  23                                   | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH \
  24                                   | ECRYPTFS_VERSIONING_PUBKEY \
  25                                   | ECRYPTFS_VERSIONING_XATTR \
  26                                   | ECRYPTFS_VERSIONING_MULTKEY \
  27                                   | ECRYPTFS_VERSIONING_DEVMISC \
  28                                   | ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION)
  29 #define ECRYPTFS_MAX_PASSWORD_LENGTH 64
  30 #define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
  31 #define ECRYPTFS_SALT_SIZE 8
  32 #define ECRYPTFS_SALT_SIZE_HEX (ECRYPTFS_SALT_SIZE*2)
  33 /* The original signature size is only for what is stored on disk; all
  34  * in-memory representations are expanded hex, so it better adapted to
  35  * be passed around or referenced on the command line */
  36 #define ECRYPTFS_SIG_SIZE 8
  37 #define ECRYPTFS_SIG_SIZE_HEX (ECRYPTFS_SIG_SIZE*2)
  38 #define ECRYPTFS_PASSWORD_SIG_SIZE ECRYPTFS_SIG_SIZE_HEX
  39 #define ECRYPTFS_MAX_KEY_BYTES 64
  40 #define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512
  41 #define ECRYPTFS_FILE_VERSION 0x03
  42 #define ECRYPTFS_MAX_PKI_NAME_BYTES 16
  43
  44 #define RFC2440_CIPHER_DES3_EDE 0x02
  45 #define RFC2440_CIPHER_CAST_5 0x03
  46 #define RFC2440_CIPHER_BLOWFISH 0x04
  47 #define RFC2440_CIPHER_AES_128 0x07
  48 #define RFC2440_CIPHER_AES_192 0x08
  49 #define RFC2440_CIPHER_AES_256 0x09
  50 #define RFC2440_CIPHER_TWOFISH 0x0a
  51 #define RFC2440_CIPHER_CAST_6 0x0b
  52
  53 #define RFC2440_CIPHER_RSA 0x01
  54
  55 /**
  56  * For convenience, we may need to pass around the encrypted session
  57  * key between kernel and userspace because the authentication token
  58  * may not be extractable.  For example, the TPM may not release the
  59  * private key, instead requiring the encrypted data and returning the
  60  * decrypted data.
  61  */
  62 struct ecryptfs_session_key {
  63 #define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT 0x00000001
  64 #define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT 0x00000002
  65 #define ECRYPTFS_CONTAINS_DECRYPTED_KEY 0x00000004
  66 #define ECRYPTFS_CONTAINS_ENCRYPTED_KEY 0x00000008
  67         u32 flags;
  68         u32 encrypted_key_size;
  69         u32 decrypted_key_size;
  70         u8 encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
  71         u8 decrypted_key[ECRYPTFS_MAX_KEY_BYTES];
  72 };
  73
  74 struct ecryptfs_password {
  75         u32 password_bytes;
  76         s32 hash_algo;
  77         u32 hash_iterations;
  78         u32 session_key_encryption_key_bytes;
  79 #define ECRYPTFS_PERSISTENT_PASSWORD 0x01
  80 #define ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET 0x02
  81         u32 flags;
  82         /* Iterated-hash concatenation of salt and passphrase */
  83         u8 session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
  84         u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
  85         /* Always in expanded hex */
  86         u8 salt[ECRYPTFS_SALT_SIZE];
  87 };
  88
  89 enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY};
  90
  91 struct ecryptfs_private_key {
  92         u32 key_size;
  93         u32 data_len;
  94         u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1];
  95         char pki_type[ECRYPTFS_MAX_PKI_NAME_BYTES + 1];
  96         u8 data[];
  97 };
  98
  99 /* May be a password or a private key */
 100 struct ecryptfs_auth_tok {
 101         u16 version; /* 8-bit major and 8-bit minor */
 102         u16 token_type;
 103 #define ECRYPTFS_ENCRYPT_ONLY 0x00000001
 104         u32 flags;
 105         struct ecryptfs_session_key session_key;
 106         u8 reserved[32];
 107         union {
 108                 struct ecryptfs_password password;
 109                 struct ecryptfs_private_key private_key;
 110         } token;
 111 } __attribute__ ((packed));
 112
 113 #endif /* _LINUX_ECRYPTFS_H */