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Linux kernel mirror (for testing)
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linux
1/*
2 * linux/fs/f2fs/f2fs_crypto.h
3 *
4 * Copied from linux/fs/ext4/ext4_crypto.h
5 *
6 * Copyright (C) 2015, Google, Inc.
7 *
8 * This contains encryption header content for f2fs
9 *
10 * Written by Michael Halcrow, 2015.
11 * Modified by Jaegeuk Kim, 2015.
12 */
13#ifndef _F2FS_CRYPTO_H
14#define _F2FS_CRYPTO_H
15
16#include <linux/fs.h>
17
18#define F2FS_KEY_DESCRIPTOR_SIZE 8
19
20/* Policy provided via an ioctl on the topmost directory */
21struct f2fs_encryption_policy {
22 char version;
23 char contents_encryption_mode;
24 char filenames_encryption_mode;
25 char flags;
26 char master_key_descriptor[F2FS_KEY_DESCRIPTOR_SIZE];
27} __attribute__((__packed__));
28
29#define F2FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
30#define F2FS_KEY_DERIVATION_NONCE_SIZE 16
31
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
38
39/**
40 * Encryption context for inode
41 *
42 * Protector format:
43 * 1 byte: Protector format (1 = this version)
44 * 1 byte: File contents encryption mode
45 * 1 byte: File names encryption mode
46 * 1 byte: Flags
47 * 8 bytes: Master Key descriptor
48 * 16 bytes: Encryption Key derivation nonce
49 */
50struct f2fs_encryption_context {
51 char format;
52 char contents_encryption_mode;
53 char filenames_encryption_mode;
54 char flags;
55 char master_key_descriptor[F2FS_KEY_DESCRIPTOR_SIZE];
56 char nonce[F2FS_KEY_DERIVATION_NONCE_SIZE];
57} __attribute__((__packed__));
58
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
67
68#define F2FS_KEY_DESC_PREFIX "f2fs:"
69#define F2FS_KEY_DESC_PREFIX_SIZE 5
70
71struct f2fs_encryption_key {
72 __u32 mode;
73 char raw[F2FS_MAX_KEY_SIZE];
74 __u32 size;
75} __attribute__((__packed__));
76
77struct f2fs_crypt_info {
78 char ci_data_mode;
79 char ci_filename_mode;
80 char ci_flags;
81 struct crypto_ablkcipher *ci_ctfm;
82 struct key *ci_keyring_key;
83 char ci_master_key[F2FS_KEY_DESCRIPTOR_SIZE];
84};
85
86#define F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
87#define F2FS_WRITE_PATH_FL 0x00000002
88
89struct f2fs_crypto_ctx {
90 union {
91 struct {
92 struct page *bounce_page; /* Ciphertext page */
93 struct page *control_page; /* Original page */
94 } w;
95 struct {
96 struct bio *bio;
97 struct work_struct work;
98 } r;
99 struct list_head free_list; /* Free list */
100 };
101 char flags; /* Flags */
102};
103
104struct f2fs_completion_result {
105 struct completion completion;
106 int res;
107};
108
109#define DECLARE_F2FS_COMPLETION_RESULT(ecr) \
110 struct f2fs_completion_result ecr = { \
111 COMPLETION_INITIALIZER((ecr).completion), 0 }
112
113static inline int f2fs_encryption_key_size(int mode)
114{
115 switch (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;
124 default:
125 BUG();
126 }
127 return 0;
128}
129
130#define F2FS_FNAME_NUM_SCATTER_ENTRIES 4
131#define F2FS_CRYPTO_BLOCK_SIZE 16
132#define F2FS_FNAME_CRYPTO_DIGEST_SIZE 32
133
134/**
135 * For encrypted symlinks, the ciphertext length is stored at the beginning
136 * of the string in little-endian format.
137 */
138struct f2fs_encrypted_symlink_data {
139 __le16 len;
140 char encrypted_path[1];
141} __attribute__((__packed__));
142
143/**
144 * This function is used to calculate the disk space required to
145 * store a filename of length l in encrypted symlink format.
146 */
147static inline u32 encrypted_symlink_data_len(u32 l)
148{
149 return (l + sizeof(struct f2fs_encrypted_symlink_data) - 1);
150}
151#endif /* _F2FS_CRYPTO_H */