1 /*
2 * fscrypt_private.h
3 *
4 * Copyright (C) 2015, Google, Inc.
5 *
6 * This contains encryption key functions.
7 *
8 * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
9 */
10
11 #ifndef _FSCRYPT_PRIVATE_H
12 #define _FSCRYPT_PRIVATE_H
13
14 #define __FS_HAS_ENCRYPTION 1
15 #include <linux/fscrypt.h>
16 #include <crypto/hash.h>
17
18 /* Encryption parameters */
19 #define FS_IV_SIZE 16
20 #define FS_AES_128_ECB_KEY_SIZE 16
21 #define FS_AES_128_CBC_KEY_SIZE 16
22 #define FS_AES_128_CTS_KEY_SIZE 16
23 #define FS_AES_256_GCM_KEY_SIZE 32
24 #define FS_AES_256_CBC_KEY_SIZE 32
25 #define FS_AES_256_CTS_KEY_SIZE 32
26 #define FS_AES_256_XTS_KEY_SIZE 64
27
28 #define FS_KEY_DERIVATION_NONCE_SIZE 16
29
30 /**
31 * Encryption context for inode
32 *
33 * Protector format:
34 * 1 byte: Protector format (1 = this version)
35 * 1 byte: File contents encryption mode
36 * 1 byte: File names encryption mode
37 * 1 byte: Flags
38 * 8 bytes: Master Key descriptor
39 * 16 bytes: Encryption Key derivation nonce
40 */
41 struct fscrypt_context {
42 u8 format;
43 u8 contents_encryption_mode;
44 u8 filenames_encryption_mode;
45 u8 flags;
46 u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
47 u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
48 } __packed;
49
50 #define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
51
52 /*
53 * A pointer to this structure is stored in the file system's in-core
54 * representation of an inode.
55 */
56 struct fscrypt_info {
57 u8 ci_data_mode;
58 u8 ci_filename_mode;
59 u8 ci_flags;
60 struct crypto_ablkcipher *ci_ctfm;
61 struct crypto_cipher *ci_essiv_tfm;
62 u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
63 };
64
65 typedef enum {
66 FS_DECRYPT = 0,
67 FS_ENCRYPT,
68 } fscrypt_direction_t;
69
70 #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
71 #define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002
72
inode_lock(struct inode * inode)73 static inline void inode_lock(struct inode *inode)
74 {
75 mutex_lock(&inode->i_mutex);
76 }
77
inode_unlock(struct inode * inode)78 static inline void inode_unlock(struct inode *inode)
79 {
80 mutex_unlock(&inode->i_mutex);
81 }
82
user_key_payload(const struct key * key)83 static inline const struct user_key_payload *user_key_payload(const struct key *key)
84 {
85 return (struct user_key_payload *)rcu_dereference_key(key);
86 }
87
88 /* bio stuffs */
89 #define REQ_OP_READ READ
90 #define REQ_OP_WRITE WRITE
91 #define bio_op(bio) ((bio)->bi_rw & 1)
92
bio_set_op_attrs(struct bio * bio,unsigned op,unsigned op_flags)93 static inline void bio_set_op_attrs(struct bio *bio, unsigned op,
94 unsigned op_flags)
95 {
96 bio->bi_rw = op | op_flags;
97 }
98
99 /* crypto.c */
100 extern int fscrypt_initialize(unsigned int cop_flags);
101 extern struct workqueue_struct *fscrypt_read_workqueue;
102 extern int fscrypt_do_page_crypto(const struct inode *inode,
103 fscrypt_direction_t rw, u64 lblk_num,
104 struct page *src_page,
105 struct page *dest_page,
106 unsigned int len, unsigned int offs,
107 gfp_t gfp_flags);
108 extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
109 gfp_t gfp_flags);
110
111 /* keyinfo.c */
112 extern void __exit fscrypt_essiv_cleanup(void);
113
114 #endif /* _FSCRYPT_PRIVATE_H */
115