2 * fscrypt_common.h: common declarations for per-file encryption
4 * Copyright (C) 2015, Google, Inc.
6 * Written by Michael Halcrow, 2015.
7 * Modified by Jaegeuk Kim, 2015.
10 #ifndef _LINUX_FSCRYPT_COMMON_H
11 #define _LINUX_FSCRYPT_COMMON_H
13 #include <linux/key.h>
16 #include <linux/bio.h>
17 #include <linux/dcache.h>
18 #include <crypto/skcipher.h>
19 #include <uapi/linux/fs.h>
21 #define FS_CRYPTO_BLOCK_SIZE 16
28 struct page *bounce_page; /* Ciphertext page */
29 struct page *control_page; /* Original page */
33 struct work_struct work;
35 struct list_head free_list; /* Free list */
41 * For encrypted symlinks, the ciphertext length is stored at the beginning
42 * of the string in little-endian format.
44 struct fscrypt_symlink_data {
46 char encrypted_path[1];
55 const struct qstr *usr_fname;
56 struct fscrypt_str disk_name;
59 struct fscrypt_str crypto_buf;
62 #define FSTR_INIT(n, l) { .name = n, .len = l }
63 #define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len)
64 #define fname_name(p) ((p)->disk_name.name)
65 #define fname_len(p) ((p)->disk_name.len)
68 * fscrypt superblock flags
70 #define FS_CFLG_OWN_PAGES (1U << 1)
73 * crypto opertions for filesystems
75 struct fscrypt_operations {
77 const char *key_prefix;
78 int (*get_context)(struct inode *, void *, size_t);
79 int (*set_context)(struct inode *, const void *, size_t, void *);
80 int (*dummy_context)(struct inode *);
81 bool (*is_encrypted)(struct inode *);
82 bool (*empty_dir)(struct inode *);
83 unsigned (*max_namelen)(struct inode *);
86 static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
88 if (inode->i_sb->s_cop->dummy_context &&
89 inode->i_sb->s_cop->dummy_context(inode))
94 static inline bool fscrypt_valid_contents_enc_mode(u32 mode)
96 return (mode == FS_ENCRYPTION_MODE_AES_256_XTS);
99 static inline bool fscrypt_valid_filenames_enc_mode(u32 mode)
101 return (mode == FS_ENCRYPTION_MODE_AES_256_CTS);
104 static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
106 if (str->len == 1 && str->name[0] == '.')
109 if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
115 static inline struct page *fscrypt_control_page(struct page *page)
117 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
118 return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
121 return ERR_PTR(-EINVAL);
125 static inline int fscrypt_has_encryption_key(const struct inode *inode)
127 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
128 return (inode->i_crypt_info != NULL);
134 #endif /* _LINUX_FSCRYPT_COMMON_H */