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192.168.1.100 / T103 / 1f884588077ad3476b9c91cbb0ee9ee0332bbb68 / . / src / kernel / linux / v4.14 / fs / crypto / fscrypt_private.h
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rjw1f884582022-01-06 17:20:42 +0800[diff] [blame^]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 */
20#define FS_IV_SIZE 16
21#define FS_AES_128_ECB_KEY_SIZE 16
22#define FS_AES_128_CBC_KEY_SIZE 16
23#define FS_AES_128_CTS_KEY_SIZE 16
24#define FS_AES_256_GCM_KEY_SIZE 32
25#define FS_AES_256_CBC_KEY_SIZE 32
26#define FS_AES_256_CTS_KEY_SIZE 32
27#define FS_AES_256_XTS_KEY_SIZE 64
28
29#define FS_KEY_DERIVATION_NONCE_SIZE 16
30
31/**
32 * Encryption context for inode
33 *
34 * Protector format:
35 * 1 byte: Protector format (1 = this version)
36 * 1 byte: File contents encryption mode
37 * 1 byte: File names encryption mode
38 * 1 byte: Flags
39 * 8 bytes: Master Key descriptor
40 * 16 bytes: Encryption Key derivation nonce
41 */
42struct fscrypt_context {
43 u8 format;
44 u8 contents_encryption_mode;
45 u8 filenames_encryption_mode;
46 u8 flags;
47 u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
48 u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
49} __packed;
50
51#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
52
53/**
54 * For encrypted symlinks, the ciphertext length is stored at the beginning
55 * of the string in little-endian format.
56 */
57struct fscrypt_symlink_data {
58 __le16 len;
59 char encrypted_path[1];
60} __packed;
61
62/*
63 * A pointer to this structure is stored in the file system's in-core
64 * representation of an inode.
65 */
66struct fscrypt_info {
67 u8 ci_data_mode;
68 u8 ci_filename_mode;
69 u8 ci_flags;
70 struct crypto_skcipher *ci_ctfm;
71 struct crypto_cipher *ci_essiv_tfm;
72 u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
73};
74
75typedef enum {
76 FS_DECRYPT = 0,
77 FS_ENCRYPT,
78} fscrypt_direction_t;
79
80#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
81#define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002
82
83static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
84 u32 filenames_mode)
85{
86 if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
87 filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
88 return true;
89
90 if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
91 filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
92 return true;
93
94 if (contents_mode == FS_ENCRYPTION_MODE_SPECK128_256_XTS &&
95 filenames_mode == FS_ENCRYPTION_MODE_SPECK128_256_CTS)
96 return true;
97
98 return false;
99}
100
101/* crypto.c */
102extern struct kmem_cache *fscrypt_info_cachep;
103extern int fscrypt_initialize(unsigned int cop_flags);
104extern int fscrypt_do_page_crypto(const struct inode *inode,
105 fscrypt_direction_t rw, u64 lblk_num,
106 struct page *src_page,
107 struct page *dest_page,
108 unsigned int len, unsigned int offs,
109 gfp_t gfp_flags);
110extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
111 gfp_t gfp_flags);
112
113/* fname.c */
114extern int fname_encrypt(struct inode *inode, const struct qstr *iname,
115 u8 *out, unsigned int olen);
116extern bool fscrypt_fname_encrypted_size(const struct inode *inode,
117 u32 orig_len, u32 max_len,
118 u32 *encrypted_len_ret);
119
120/* keyinfo.c */
121extern void __exit fscrypt_essiv_cleanup(void);
122
123#endif /* _FSCRYPT_PRIVATE_H */