fscrypt_private.h (3eb66e91a25497065c5322b1268cbc3953642227) fscrypt_private.h (643fa9612bf1a29153eee46fd398117632f93cbe)
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * fscrypt_private.h
4 *
5 * Copyright (C) 2015, Google, Inc.
6 *
7 * This contains encryption key functions.
8 *
9 * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
10 */
11
12#ifndef _FSCRYPT_PRIVATE_H
13#define _FSCRYPT_PRIVATE_H
14
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * fscrypt_private.h
4 *
5 * Copyright (C) 2015, Google, Inc.
6 *
7 * This contains encryption key functions.
8 *
9 * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
10 */
11
12#ifndef _FSCRYPT_PRIVATE_H
13#define _FSCRYPT_PRIVATE_H
14
15#define __FS_HAS_ENCRYPTION 1
16#include <linux/fscrypt.h>
17#include <crypto/hash.h>
18
19/* Encryption parameters */
15#include <linux/fscrypt.h>
16#include <crypto/hash.h>
17
18/* Encryption parameters */
20#define FS_IV_SIZE 16
21#define FS_KEY_DERIVATION_NONCE_SIZE 16
22
23/**
24 * Encryption context for inode
25 *
26 * Protector format:
27 * 1 byte: Protector format (1 = this version)
28 * 1 byte: File contents encryption mode

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47 * of the string in little-endian format.
48 */
49struct fscrypt_symlink_data {
50 __le16 len;
51 char encrypted_path[1];
52} __packed;
53
54/*
19#define FS_KEY_DERIVATION_NONCE_SIZE 16
20
21/**
22 * Encryption context for inode
23 *
24 * Protector format:
25 * 1 byte: Protector format (1 = this version)
26 * 1 byte: File contents encryption mode

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45 * of the string in little-endian format.
46 */
47struct fscrypt_symlink_data {
48 __le16 len;
49 char encrypted_path[1];
50} __packed;
51
52/*
55 * A pointer to this structure is stored in the file system's in-core
56 * representation of an inode.
53 * fscrypt_info - the "encryption key" for an inode
54 *
55 * When an encrypted file's key is made available, an instance of this struct is
56 * allocated and stored in ->i_crypt_info. Once created, it remains until the
57 * inode is evicted.
57 */
58struct fscrypt_info {
58 */
59struct fscrypt_info {
60
61 /* The actual crypto transform used for encryption and decryption */
62 struct crypto_skcipher *ci_ctfm;
63
64 /*
65 * Cipher for ESSIV IV generation. Only set for CBC contents
66 * encryption, otherwise is NULL.
67 */
68 struct crypto_cipher *ci_essiv_tfm;
69
70 /*
71 * Encryption mode used for this inode. It corresponds to either
72 * ci_data_mode or ci_filename_mode, depending on the inode type.
73 */
74 struct fscrypt_mode *ci_mode;
75
76 /*
77 * If non-NULL, then this inode uses a master key directly rather than a
78 * derived key, and ci_ctfm will equal ci_master_key->mk_ctfm.
79 * Otherwise, this inode uses a derived key.
80 */
81 struct fscrypt_master_key *ci_master_key;
82
83 /* fields from the fscrypt_context */
59 u8 ci_data_mode;
60 u8 ci_filename_mode;
61 u8 ci_flags;
84 u8 ci_data_mode;
85 u8 ci_filename_mode;
86 u8 ci_flags;
62 struct crypto_skcipher *ci_ctfm;
63 struct crypto_cipher *ci_essiv_tfm;
64 u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
87 u8 ci_master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
88 u8 ci_nonce[FS_KEY_DERIVATION_NONCE_SIZE];
65};
66
67typedef enum {
68 FS_DECRYPT = 0,
69 FS_ENCRYPT,
70} fscrypt_direction_t;
71
72#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001

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78 if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
79 filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
80 return true;
81
82 if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
83 filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
84 return true;
85
89};
90
91typedef enum {
92 FS_DECRYPT = 0,
93 FS_ENCRYPT,
94} fscrypt_direction_t;
95
96#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001

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102 if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
103 filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
104 return true;
105
106 if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
107 filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
108 return true;
109
110 if (contents_mode == FS_ENCRYPTION_MODE_ADIANTUM &&
111 filenames_mode == FS_ENCRYPTION_MODE_ADIANTUM)
112 return true;
113
86 return false;
87}
88
89/* crypto.c */
90extern struct kmem_cache *fscrypt_info_cachep;
91extern int fscrypt_initialize(unsigned int cop_flags);
92extern int fscrypt_do_page_crypto(const struct inode *inode,
93 fscrypt_direction_t rw, u64 lblk_num,

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102extern void __printf(3, 4) __cold
103fscrypt_msg(struct super_block *sb, const char *level, const char *fmt, ...);
104
105#define fscrypt_warn(sb, fmt, ...) \
106 fscrypt_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__)
107#define fscrypt_err(sb, fmt, ...) \
108 fscrypt_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__)
109
114 return false;
115}
116
117/* crypto.c */
118extern struct kmem_cache *fscrypt_info_cachep;
119extern int fscrypt_initialize(unsigned int cop_flags);
120extern int fscrypt_do_page_crypto(const struct inode *inode,
121 fscrypt_direction_t rw, u64 lblk_num,

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130extern void __printf(3, 4) __cold
131fscrypt_msg(struct super_block *sb, const char *level, const char *fmt, ...);
132
133#define fscrypt_warn(sb, fmt, ...) \
134 fscrypt_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__)
135#define fscrypt_err(sb, fmt, ...) \
136 fscrypt_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__)
137
138#define FSCRYPT_MAX_IV_SIZE 32
139
140union fscrypt_iv {
141 struct {
142 /* logical block number within the file */
143 __le64 lblk_num;
144
145 /* per-file nonce; only set in DIRECT_KEY mode */
146 u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
147 };
148 u8 raw[FSCRYPT_MAX_IV_SIZE];
149};
150
151void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
152 const struct fscrypt_info *ci);
153
110/* fname.c */
111extern int fname_encrypt(struct inode *inode, const struct qstr *iname,
112 u8 *out, unsigned int olen);
113extern bool fscrypt_fname_encrypted_size(const struct inode *inode,
114 u32 orig_len, u32 max_len,
115 u32 *encrypted_len_ret);
116
117/* keyinfo.c */
154/* fname.c */
155extern int fname_encrypt(struct inode *inode, const struct qstr *iname,
156 u8 *out, unsigned int olen);
157extern bool fscrypt_fname_encrypted_size(const struct inode *inode,
158 u32 orig_len, u32 max_len,
159 u32 *encrypted_len_ret);
160
161/* keyinfo.c */
162
163struct fscrypt_mode {
164 const char *friendly_name;
165 const char *cipher_str;
166 int keysize;
167 int ivsize;
168 bool logged_impl_name;
169 bool needs_essiv;
170};
171
118extern void __exit fscrypt_essiv_cleanup(void);
119
120#endif /* _FSCRYPT_PRIVATE_H */
172extern void __exit fscrypt_essiv_cleanup(void);
173
174#endif /* _FSCRYPT_PRIVATE_H */