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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
3325bea5 TT |
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 | ||
734f0d24 DC |
15 | #define __FS_HAS_ENCRYPTION 1 |
16 | #include <linux/fscrypt.h> | |
b7e7cf7a | 17 | #include <crypto/hash.h> |
3325bea5 | 18 | |
cc4e0df0 | 19 | /* Encryption parameters */ |
11b8818e | 20 | #define FS_KEY_DERIVATION_NONCE_SIZE 16 |
cc4e0df0 TT |
21 | |
22 | /** | |
23 | * Encryption context for inode | |
24 | * | |
25 | * Protector format: | |
26 | * 1 byte: Protector format (1 = this version) | |
27 | * 1 byte: File contents encryption mode | |
28 | * 1 byte: File names encryption mode | |
29 | * 1 byte: Flags | |
30 | * 8 bytes: Master Key descriptor | |
31 | * 16 bytes: Encryption Key derivation nonce | |
32 | */ | |
33 | struct fscrypt_context { | |
34 | u8 format; | |
35 | u8 contents_encryption_mode; | |
36 | u8 filenames_encryption_mode; | |
37 | u8 flags; | |
38 | u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; | |
39 | u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; | |
40 | } __packed; | |
41 | ||
42 | #define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1 | |
43 | ||
0eaab5b1 EB |
44 | /** |
45 | * For encrypted symlinks, the ciphertext length is stored at the beginning | |
46 | * of the string in little-endian format. | |
47 | */ | |
48 | struct fscrypt_symlink_data { | |
49 | __le16 len; | |
50 | char encrypted_path[1]; | |
51 | } __packed; | |
52 | ||
cc4e0df0 | 53 | /* |
8094c3ce EB |
54 | * fscrypt_info - the "encryption key" for an inode |
55 | * | |
56 | * When an encrypted file's key is made available, an instance of this struct is | |
57 | * allocated and stored in ->i_crypt_info. Once created, it remains until the | |
58 | * inode is evicted. | |
cc4e0df0 TT |
59 | */ |
60 | struct fscrypt_info { | |
8094c3ce EB |
61 | |
62 | /* The actual crypto transform used for encryption and decryption */ | |
63 | struct crypto_skcipher *ci_ctfm; | |
64 | ||
65 | /* | |
66 | * Cipher for ESSIV IV generation. Only set for CBC contents | |
67 | * encryption, otherwise is NULL. | |
68 | */ | |
69 | struct crypto_cipher *ci_essiv_tfm; | |
70 | ||
71 | /* | |
72 | * Encryption mode used for this inode. It corresponds to either | |
73 | * ci_data_mode or ci_filename_mode, depending on the inode type. | |
74 | */ | |
75 | struct fscrypt_mode *ci_mode; | |
76 | ||
77 | /* | |
78 | * If non-NULL, then this inode uses a master key directly rather than a | |
79 | * derived key, and ci_ctfm will equal ci_master_key->mk_ctfm. | |
80 | * Otherwise, this inode uses a derived key. | |
81 | */ | |
82 | struct fscrypt_master_key *ci_master_key; | |
83 | ||
84 | /* fields from the fscrypt_context */ | |
cc4e0df0 TT |
85 | u8 ci_data_mode; |
86 | u8 ci_filename_mode; | |
87 | u8 ci_flags; | |
8094c3ce EB |
88 | u8 ci_master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; |
89 | u8 ci_nonce[FS_KEY_DERIVATION_NONCE_SIZE]; | |
cc4e0df0 TT |
90 | }; |
91 | ||
58ae7468 RW |
92 | typedef enum { |
93 | FS_DECRYPT = 0, | |
94 | FS_ENCRYPT, | |
95 | } fscrypt_direction_t; | |
96 | ||
cc4e0df0 | 97 | #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001 |
6a34e4d2 | 98 | #define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002 |
cc4e0df0 | 99 | |
bb8179e5 EB |
100 | static inline bool fscrypt_valid_enc_modes(u32 contents_mode, |
101 | u32 filenames_mode) | |
102 | { | |
103 | if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC && | |
104 | filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS) | |
105 | return true; | |
106 | ||
107 | if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS && | |
108 | filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS) | |
109 | return true; | |
110 | ||
8094c3ce EB |
111 | if (contents_mode == FS_ENCRYPTION_MODE_ADIANTUM && |
112 | filenames_mode == FS_ENCRYPTION_MODE_ADIANTUM) | |
113 | return true; | |
114 | ||
bb8179e5 EB |
115 | return false; |
116 | } | |
117 | ||
b98701df | 118 | /* crypto.c */ |
e4de782a | 119 | extern struct kmem_cache *fscrypt_info_cachep; |
58ae7468 | 120 | extern int fscrypt_initialize(unsigned int cop_flags); |
58ae7468 RW |
121 | extern int fscrypt_do_page_crypto(const struct inode *inode, |
122 | fscrypt_direction_t rw, u64 lblk_num, | |
123 | struct page *src_page, | |
124 | struct page *dest_page, | |
125 | unsigned int len, unsigned int offs, | |
126 | gfp_t gfp_flags); | |
127 | extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx, | |
128 | gfp_t gfp_flags); | |
54222025 | 129 | extern const struct dentry_operations fscrypt_d_ops; |
b98701df | 130 | |
544d08fd EB |
131 | extern void __printf(3, 4) __cold |
132 | fscrypt_msg(struct super_block *sb, const char *level, const char *fmt, ...); | |
133 | ||
134 | #define fscrypt_warn(sb, fmt, ...) \ | |
135 | fscrypt_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__) | |
136 | #define fscrypt_err(sb, fmt, ...) \ | |
137 | fscrypt_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__) | |
138 | ||
8094c3ce EB |
139 | #define FSCRYPT_MAX_IV_SIZE 32 |
140 | ||
141 | union fscrypt_iv { | |
142 | struct { | |
143 | /* logical block number within the file */ | |
144 | __le64 lblk_num; | |
145 | ||
146 | /* per-file nonce; only set in DIRECT_KEY mode */ | |
147 | u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; | |
148 | }; | |
149 | u8 raw[FSCRYPT_MAX_IV_SIZE]; | |
150 | }; | |
151 | ||
152 | void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, | |
153 | const struct fscrypt_info *ci); | |
154 | ||
76e81d6d | 155 | /* fname.c */ |
50c961de EB |
156 | extern int fname_encrypt(struct inode *inode, const struct qstr *iname, |
157 | u8 *out, unsigned int olen); | |
b9db0b4a EB |
158 | extern bool fscrypt_fname_encrypted_size(const struct inode *inode, |
159 | u32 orig_len, u32 max_len, | |
160 | u32 *encrypted_len_ret); | |
76e81d6d | 161 | |
b7e7cf7a | 162 | /* keyinfo.c */ |
8094c3ce EB |
163 | |
164 | struct fscrypt_mode { | |
165 | const char *friendly_name; | |
166 | const char *cipher_str; | |
167 | int keysize; | |
168 | int ivsize; | |
169 | bool logged_impl_name; | |
170 | bool needs_essiv; | |
171 | }; | |
172 | ||
b7e7cf7a DW |
173 | extern void __exit fscrypt_essiv_cleanup(void); |
174 | ||
3325bea5 | 175 | #endif /* _FSCRYPT_PRIVATE_H */ |