[mirror_ubuntu-artful-kernel.git] / include / linux / fscrypt_common.h

/*
 * fscrypt_common.h: common declarations for per-file encryption
 *
 * Copyright (C) 2015, Google, Inc.
 *
 * Written by Michael Halcrow, 2015.
 * Modified by Jaegeuk Kim, 2015.
 */

#ifndef _LINUX_FSCRYPT_COMMON_H
#define _LINUX_FSCRYPT_COMMON_H

#include <linux/key.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/bio.h>
#include <linux/dcache.h>
#include <crypto/skcipher.h>
#include <uapi/linux/fs.h>

#define FS_CRYPTO_BLOCK_SIZE		16

struct fscrypt_info;

struct fscrypt_ctx {
	union {
		struct {
			struct page *bounce_page;	/* Ciphertext page */
			struct page *control_page;	/* Original page  */
		} w;
		struct {
			struct bio *bio;
			struct work_struct work;
		} r;
		struct list_head free_list;	/* Free list */
	};
	u8 flags;				/* Flags */
};

/**
 * For encrypted symlinks, the ciphertext length is stored at the beginning
 * of the string in little-endian format.
 */
struct fscrypt_symlink_data {
	__le16 len;
	char encrypted_path[1];
} __packed;

/**
 * This function is used to calculate the disk space required to
 * store a filename of length l in encrypted symlink format.
 */
static inline u32 fscrypt_symlink_data_len(u32 l)
{
	if (l < FS_CRYPTO_BLOCK_SIZE)
		l = FS_CRYPTO_BLOCK_SIZE;
	return (l + sizeof(struct fscrypt_symlink_data) - 1);
}

struct fscrypt_str {
	unsigned char *name;
	u32 len;
};

struct fscrypt_name {
	const struct qstr *usr_fname;
	struct fscrypt_str disk_name;
	u32 hash;
	u32 minor_hash;
	struct fscrypt_str crypto_buf;
};

#define FSTR_INIT(n, l)		{ .name = n, .len = l }
#define FSTR_TO_QSTR(f)		QSTR_INIT((f)->name, (f)->len)
#define fname_name(p)		((p)->disk_name.name)
#define fname_len(p)		((p)->disk_name.len)

/*
 * fscrypt superblock flags
 */
#define FS_CFLG_OWN_PAGES (1U << 1)

/*
 * crypto opertions for filesystems
 */
struct fscrypt_operations {
	unsigned int flags;
	const char *key_prefix;
	int (*get_context)(struct inode *, void *, size_t);
	int (*prepare_context)(struct inode *);
	int (*set_context)(struct inode *, const void *, size_t, void *);
	int (*dummy_context)(struct inode *);
	bool (*is_encrypted)(struct inode *);
	bool (*empty_dir)(struct inode *);
	unsigned (*max_namelen)(struct inode *);
};

static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
{
	if (inode->i_sb->s_cop->dummy_context &&
				inode->i_sb->s_cop->dummy_context(inode))
		return true;
	return false;
}

static inline bool fscrypt_valid_contents_enc_mode(u32 mode)
{
	return (mode == FS_ENCRYPTION_MODE_AES_256_XTS);
}

static inline bool fscrypt_valid_filenames_enc_mode(u32 mode)
{
	return (mode == FS_ENCRYPTION_MODE_AES_256_CTS);
}

static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
{
	if (str->len == 1 && str->name[0] == '.')
		return true;

	if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
		return true;

	return false;
}

static inline struct page *fscrypt_control_page(struct page *page)
{
#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
#else
	WARN_ON_ONCE(1);
	return ERR_PTR(-EINVAL);
#endif
}

static inline int fscrypt_has_encryption_key(const struct inode *inode)
{
#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	return (inode->i_crypt_info != NULL);
#else
	return 0;
#endif
}

#endif	/* _LINUX_FSCRYPT_COMMON_H */
Commit	Line	Data
46f47e48 EB	1	/*
	2	* fscrypt_common.h: common declarations for per-file encryption
	3	*
	4	* Copyright (C) 2015, Google, Inc.
	5	*
	6	* Written by Michael Halcrow, 2015.
	7	* Modified by Jaegeuk Kim, 2015.
	8	*/
	9
	10	#ifndef _LINUX_FSCRYPT_COMMON_H
	11	#define _LINUX_FSCRYPT_COMMON_H
	12
	13	#include <linux/key.h>
	14	#include <linux/fs.h>
	15	#include <linux/mm.h>
	16	#include <linux/bio.h>
	17	#include <linux/dcache.h>
	18	#include <crypto/skcipher.h>
	19	#include <uapi/linux/fs.h>
	20
	21	#define FS_CRYPTO_BLOCK_SIZE 16
	22
	23	struct fscrypt_info;
	24
	25	struct fscrypt_ctx {
	26	union {
	27	struct {
	28	struct page bounce_page; / Ciphertext page */
	29	struct page control_page; / Original page */
	30	} w;
	31	struct {
	32	struct bio *bio;
	33	struct work_struct work;
	34	} r;
	35	struct list_head free_list; /* Free list */
	36	};
	37	u8 flags; /* Flags */
	38	};
	39
	40	/**
	41	* For encrypted symlinks, the ciphertext length is stored at the beginning
	42	* of the string in little-endian format.
	43	*/
	44	struct fscrypt_symlink_data {
	45	__le16 len;
	46	char encrypted_path[1];
	47	} __packed;
	48
	49	/**
	50	* This function is used to calculate the disk space required to
	51	* store a filename of length l in encrypted symlink format.
	52	*/
	53	static inline u32 fscrypt_symlink_data_len(u32 l)
	54	{
	55	if (l < FS_CRYPTO_BLOCK_SIZE)
	56	l = FS_CRYPTO_BLOCK_SIZE;
	57	return (l + sizeof(struct fscrypt_symlink_data) - 1);
	58	}
	59
	60	struct fscrypt_str {
	61	unsigned char *name;
	62	u32 len;
	63	};
	64
65	struct fscrypt_name {
66	const struct qstr *usr_fname;
67	struct fscrypt_str disk_name;
68	u32 hash;
69	u32 minor_hash;
70	struct fscrypt_str crypto_buf;
71	};
72
73	#define FSTR_INIT(n, l) { .name = n, .len = l }
74	#define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len)
75	#define fname_name(p) ((p)->disk_name.name)
76	#define fname_len(p) ((p)->disk_name.len)
77
78	/*
79	* fscrypt superblock flags
80	*/
81	#define FS_CFLG_OWN_PAGES (1U << 1)
82
83	/*
84	* crypto opertions for filesystems
85	*/
86	struct fscrypt_operations {
87	unsigned int flags;
88	const char *key_prefix;
89	int (get_context)(struct inode , void *, size_t);
90	int (prepare_context)(struct inode );
91	int (set_context)(struct inode , const void , size_t, void );
92	int (dummy_context)(struct inode );
93	bool (is_encrypted)(struct inode );
94	bool (empty_dir)(struct inode );
95	unsigned (max_namelen)(struct inode );
96	};
97
98	static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
99	{
100	if (inode->i_sb->s_cop->dummy_context &&
101	inode->i_sb->s_cop->dummy_context(inode))
102	return true;
103	return false;
104	}
105
106	static inline bool fscrypt_valid_contents_enc_mode(u32 mode)
107	{
108	return (mode == FS_ENCRYPTION_MODE_AES_256_XTS);
109	}
110
111	static inline bool fscrypt_valid_filenames_enc_mode(u32 mode)
112	{
113	return (mode == FS_ENCRYPTION_MODE_AES_256_CTS);
114	}
115
116	static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
117	{
118	if (str->len == 1 && str->name[0] == '.')
119	return true;
120
121	if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
122	return true;
123
124	return false;
125	}
126
127	static inline struct page fscrypt_control_page(struct page page)
128	{
129	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
130	return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
131	#else
132	WARN_ON_ONCE(1);
133	return ERR_PTR(-EINVAL);
134	#endif
135	}
136
137	static inline int fscrypt_has_encryption_key(const struct inode *inode)
138	{
139	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
140	return (inode->i_crypt_info != NULL);
141	#else
142	return 0;
143	#endif
144	}
145
146	#endif /* _LINUX_FSCRYPT_COMMON_H */