[mirror_ubuntu-bionic-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;

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 (*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
46f47e48 EB	49	struct fscrypt_str {
	50	unsigned char *name;
	51	u32 len;
	52	};
	53
	54	struct fscrypt_name {
	55	const struct qstr *usr_fname;
	56	struct fscrypt_str disk_name;
	57	u32 hash;
	58	u32 minor_hash;
	59	struct fscrypt_str crypto_buf;
	60	};
	61
	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)
	66
	67	/*
	68	* fscrypt superblock flags
	69	*/
	70	#define FS_CFLG_OWN_PAGES (1U << 1)
	71
	72	/*
	73	* crypto opertions for filesystems
	74	*/
	75	struct fscrypt_operations {
	76	unsigned int flags;
	77	const char *key_prefix;
	78	int (get_context)(struct inode , void *, size_t);
46f47e48 EB	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 );
	84	};
	85
	86	static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
	87	{
	88	if (inode->i_sb->s_cop->dummy_context &&
	89	inode->i_sb->s_cop->dummy_context(inode))
	90	return true;
	91	return false;
	92	}
	93
	94	static inline bool fscrypt_valid_contents_enc_mode(u32 mode)
	95	{
	96	return (mode == FS_ENCRYPTION_MODE_AES_256_XTS);
	97	}
	98
	99	static inline bool fscrypt_valid_filenames_enc_mode(u32 mode)
	100	{
	101	return (mode == FS_ENCRYPTION_MODE_AES_256_CTS);
	102	}
	103
	104	static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
	105	{
	106	if (str->len == 1 && str->name[0] == '.')
	107	return true;
	108
	109	if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
	110	return true;
	111
	112	return false;
	113	}
	114
	115	static inline struct page fscrypt_control_page(struct page page)
	116	{
	117	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	118	return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
	119	#else
	120	WARN_ON_ONCE(1);
	121	return ERR_PTR(-EINVAL);
	122	#endif
	123	}
	124
	125	static inline int fscrypt_has_encryption_key(const struct inode *inode)
	126	{
	127	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	128	return (inode->i_crypt_info != NULL);
	129	#else
	130	return 0;
	131	#endif
	132	}
	133
	134	#endif /* _LINUX_FSCRYPT_COMMON_H */