2 * linux/fs/f2fs/f2fs_crypto.h
4 * Copied from linux/fs/ext4/ext4_crypto.h
6 * Copyright (C) 2015, Google, Inc.
8 * This contains encryption header content for f2fs
10 * Written by Michael Halcrow, 2015.
11 * Modified by Jaegeuk Kim, 2015.
13 #ifndef _F2FS_CRYPTO_H
14 #define _F2FS_CRYPTO_H
18 #define F2FS_KEY_DESCRIPTOR_SIZE 8
20 /* Policy provided via an ioctl on the topmost directory */
21 struct f2fs_encryption_policy {
23 char contents_encryption_mode;
24 char filenames_encryption_mode;
26 char master_key_descriptor[F2FS_KEY_DESCRIPTOR_SIZE];
27 } __attribute__((__packed__));
29 #define F2FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
30 #define F2FS_KEY_DERIVATION_NONCE_SIZE 16
32 #define F2FS_POLICY_FLAGS_PAD_4 0x00
33 #define F2FS_POLICY_FLAGS_PAD_8 0x01
34 #define F2FS_POLICY_FLAGS_PAD_16 0x02
35 #define F2FS_POLICY_FLAGS_PAD_32 0x03
36 #define F2FS_POLICY_FLAGS_PAD_MASK 0x03
37 #define F2FS_POLICY_FLAGS_VALID 0x03
40 * Encryption context for inode
43 * 1 byte: Protector format (1 = this version)
44 * 1 byte: File contents encryption mode
45 * 1 byte: File names encryption mode
47 * 8 bytes: Master Key descriptor
48 * 16 bytes: Encryption Key derivation nonce
50 struct f2fs_encryption_context {
52 char contents_encryption_mode;
53 char filenames_encryption_mode;
55 char master_key_descriptor[F2FS_KEY_DESCRIPTOR_SIZE];
56 char nonce[F2FS_KEY_DERIVATION_NONCE_SIZE];
57 } __attribute__((__packed__));
59 /* Encryption parameters */
60 #define F2FS_XTS_TWEAK_SIZE 16
61 #define F2FS_AES_128_ECB_KEY_SIZE 16
62 #define F2FS_AES_256_GCM_KEY_SIZE 32
63 #define F2FS_AES_256_CBC_KEY_SIZE 32
64 #define F2FS_AES_256_CTS_KEY_SIZE 32
65 #define F2FS_AES_256_XTS_KEY_SIZE 64
66 #define F2FS_MAX_KEY_SIZE 64
68 #define F2FS_KEY_DESC_PREFIX "f2fs:"
69 #define F2FS_KEY_DESC_PREFIX_SIZE 5
71 struct f2fs_encryption_key {
73 char raw[F2FS_MAX_KEY_SIZE];
75 } __attribute__((__packed__));
77 struct f2fs_crypt_info {
79 char ci_filename_mode;
81 struct crypto_ablkcipher *ci_ctfm;
82 struct key *ci_keyring_key;
83 char ci_master_key[F2FS_KEY_DESCRIPTOR_SIZE];
86 #define F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
87 #define F2FS_WRITE_PATH_FL 0x00000002
89 struct f2fs_crypto_ctx {
92 struct page *bounce_page; /* Ciphertext page */
93 struct page *control_page; /* Original page */
97 struct work_struct work;
99 struct list_head free_list; /* Free list */
101 char flags; /* Flags */
104 struct f2fs_completion_result {
105 struct completion completion;
109 #define DECLARE_F2FS_COMPLETION_RESULT(ecr) \
110 struct f2fs_completion_result ecr = { \
111 COMPLETION_INITIALIZER((ecr).completion), 0 }
113 static inline int f2fs_encryption_key_size(int mode)
116 case F2FS_ENCRYPTION_MODE_AES_256_XTS:
117 return F2FS_AES_256_XTS_KEY_SIZE;
118 case F2FS_ENCRYPTION_MODE_AES_256_GCM:
119 return F2FS_AES_256_GCM_KEY_SIZE;
120 case F2FS_ENCRYPTION_MODE_AES_256_CBC:
121 return F2FS_AES_256_CBC_KEY_SIZE;
122 case F2FS_ENCRYPTION_MODE_AES_256_CTS:
123 return F2FS_AES_256_CTS_KEY_SIZE;
130 #define F2FS_FNAME_NUM_SCATTER_ENTRIES 4
131 #define F2FS_CRYPTO_BLOCK_SIZE 16
132 #define F2FS_FNAME_CRYPTO_DIGEST_SIZE 32
135 * For encrypted symlinks, the ciphertext length is stored at the beginning
136 * of the string in little-endian format.
138 struct f2fs_encrypted_symlink_data {
140 char encrypted_path[1];
141 } __attribute__((__packed__));
144 * This function is used to calculate the disk space required to
145 * store a filename of length l in encrypted symlink format.
147 static inline u32 encrypted_symlink_data_len(u32 l)
149 return (l + sizeof(struct f2fs_encrypted_symlink_data) - 1);
151 #endif /* _F2FS_CRYPTO_H */