eCryptfs: export global eCryptfs definitions to include/linux/ecryptfs.h

Some eCryptfs specific definitions, such as the current version and the
authentication token structure, are moved to the new include file
'include/linux/ecryptfs.h', in order to be available for all kernel
subsystems.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Acked-by: Gianluca Ramunno <ramunno@polito.it>
Acked-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

1 files changed, 113 insertions, 0 deletions

diff --git a/include/linux/ecryptfs.h b/include/linux/ecryptfs.h
new file mode 100644
index 000000000000..2224a8c0cb64
--- /dev/null
+++ b/include/linux/ecryptfs.h
@@ -0,0 +1,113 @@
+#ifndef _LINUX_ECRYPTFS_H
+#define _LINUX_ECRYPTFS_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_FILE_VERSION 0x03
+#define ECRYPTFS_MAX_PKI_NAME_BYTES 16
+
+#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));
+
+#endif /* _LINUX_ECRYPTFS_H */