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

/*
 * General per-file encryption definition
 *
 * Copyright (C) 2015, Google, Inc.
 *
 * Written by Michael Halcrow, 2015.
 * Modified by Jaegeuk Kim, 2015.
 */

#ifndef _LINUX_FSCRYPTO_H
#define _LINUX_FSCRYPTO_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;

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 */
	u8 mode;				/* Encryption mode for tfm */
};

/**
 * 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_INPLACE_ENCRYPTION (1U << 1)

/*
 * crypto opertions for filesystems
 */
struct fscrypt_operations {
	unsigned int flags;
	int (*get_context)(struct inode *, void *, size_t);
	int (*key_prefix)(struct inode *, u8 **);
	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
}

static inline void fscrypt_set_encrypted_dentry(struct dentry *dentry)
{
#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	spin_lock(&dentry->d_lock);
	dentry->d_flags |= DCACHE_ENCRYPTED_WITH_KEY;
	spin_unlock(&dentry->d_lock);
#endif
}

#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
extern const struct dentry_operations fscrypt_d_ops;
#endif

static inline void fscrypt_set_d_op(struct dentry *dentry)
{
#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	d_set_d_op(dentry, &fscrypt_d_ops);
#endif
}

#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
/* crypto.c */
extern struct kmem_cache *fscrypt_info_cachep;

extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t);
extern void fscrypt_release_ctx(struct fscrypt_ctx *);
extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
						unsigned int, unsigned int,
						pgoff_t, gfp_t);
extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int,
				unsigned int, pgoff_t);
extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
extern void fscrypt_pullback_bio_page(struct page **, bool);
extern void fscrypt_restore_control_page(struct page *);
extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
						unsigned int);
/* policy.c */
extern int fscrypt_ioctl_set_policy(struct file *, const void __user *);
extern int fscrypt_ioctl_get_policy(struct file *, void __user *);
extern int fscrypt_has_permitted_context(struct inode *, struct inode *);
extern int fscrypt_inherit_context(struct inode *, struct inode *,
					void *, bool);
/* keyinfo.c */
extern int fscrypt_get_encryption_info(struct inode *);
extern void fscrypt_put_encryption_info(struct inode *, struct fscrypt_info *);

/* fname.c */
extern int fscrypt_setup_filename(struct inode *, const struct qstr *,
				int lookup, struct fscrypt_name *);
extern void fscrypt_free_filename(struct fscrypt_name *);
extern u32 fscrypt_fname_encrypted_size(const struct inode *, u32);
extern int fscrypt_fname_alloc_buffer(const struct inode *, u32,
				struct fscrypt_str *);
extern void fscrypt_fname_free_buffer(struct fscrypt_str *);
extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
			const struct fscrypt_str *, struct fscrypt_str *);
extern int fscrypt_fname_usr_to_disk(struct inode *, const struct qstr *,
			struct fscrypt_str *);
#endif

/* crypto.c */
static inline struct fscrypt_ctx *fscrypt_notsupp_get_ctx(const struct inode *i,
							gfp_t f)
{
	return ERR_PTR(-EOPNOTSUPP);
}

static inline void fscrypt_notsupp_release_ctx(struct fscrypt_ctx *c)
{
	return;
}

static inline struct page *fscrypt_notsupp_encrypt_page(const struct inode *i,
						struct page *p,
						unsigned int len,
						unsigned int offs,
						pgoff_t index, gfp_t f)
{
	return ERR_PTR(-EOPNOTSUPP);
}

static inline int fscrypt_notsupp_decrypt_page(const struct inode *i, struct page *p,
						unsigned int len, unsigned int offs,
						pgoff_t index)
{
	return -EOPNOTSUPP;
}

static inline void fscrypt_notsupp_decrypt_bio_pages(struct fscrypt_ctx *c,
						struct bio *b)
{
	return;
}

static inline void fscrypt_notsupp_pullback_bio_page(struct page **p, bool b)
{
	return;
}

static inline void fscrypt_notsupp_restore_control_page(struct page *p)
{
	return;
}

static inline int fscrypt_notsupp_zeroout_range(const struct inode *i, pgoff_t p,
					sector_t s, unsigned int f)
{
	return -EOPNOTSUPP;
}

/* policy.c */
static inline int fscrypt_notsupp_ioctl_set_policy(struct file *f,
				const void __user *arg)
{
	return -EOPNOTSUPP;
}

static inline int fscrypt_notsupp_ioctl_get_policy(struct file *f,
				void __user *arg)
{
	return -EOPNOTSUPP;
}

static inline int fscrypt_notsupp_has_permitted_context(struct inode *p,
				struct inode *i)
{
	return 0;
}

static inline int fscrypt_notsupp_inherit_context(struct inode *p,
				struct inode *i, void *v, bool b)
{
	return -EOPNOTSUPP;
}

/* keyinfo.c */
static inline int fscrypt_notsupp_get_encryption_info(struct inode *i)
{
	return -EOPNOTSUPP;
}

static inline void fscrypt_notsupp_put_encryption_info(struct inode *i,
					struct fscrypt_info *f)
{
	return;
}

 /* fname.c */
static inline int fscrypt_notsupp_setup_filename(struct inode *dir,
			const struct qstr *iname,
			int lookup, struct fscrypt_name *fname)
{
	if (dir->i_sb->s_cop->is_encrypted(dir))
		return -EOPNOTSUPP;

	memset(fname, 0, sizeof(struct fscrypt_name));
	fname->usr_fname = iname;
	fname->disk_name.name = (unsigned char *)iname->name;
	fname->disk_name.len = iname->len;
	return 0;
}

static inline void fscrypt_notsupp_free_filename(struct fscrypt_name *fname)
{
	return;
}

static inline u32 fscrypt_notsupp_fname_encrypted_size(struct inode *i, u32 s)
{
	/* never happens */
	WARN_ON(1);
	return 0;
}

static inline int fscrypt_notsupp_fname_alloc_buffer(struct inode *inode,
				u32 ilen, struct fscrypt_str *crypto_str)
{
	return -EOPNOTSUPP;
}

static inline void fscrypt_notsupp_fname_free_buffer(struct fscrypt_str *c)
{
	return;
}

static inline int fscrypt_notsupp_fname_disk_to_usr(struct inode *inode,
			u32 hash, u32 minor_hash,
			const struct fscrypt_str *iname,
			struct fscrypt_str *oname)
{
	return -EOPNOTSUPP;
}

static inline int fscrypt_notsupp_fname_usr_to_disk(struct inode *inode,
			const struct qstr *iname,
			struct fscrypt_str *oname)
{
	return -EOPNOTSUPP;
}
#endif	/* _LINUX_FSCRYPTO_H */
Commit	Line	Data
0b81d077 JK	1	/*
	2	* General per-file encryption definition
	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_FSCRYPTO_H
	11	#define _LINUX_FSCRYPTO_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>
d407574e	18	#include <crypto/skcipher.h>
0b81d077 JK	19	#include <uapi/linux/fs.h>
0b81d077 JK	20
cc4e0df0	21	#define FS_CRYPTO_BLOCK_SIZE 16
0b81d077	22
cc4e0df0 TT	23	struct fscrypt_info;
cc4e0df0 TT	24	struct fscrypt_ctx;
0b81d077 JK	25
	26	struct fscrypt_ctx {
	27	union {
	28	struct {
	29	struct page bounce_page; / Ciphertext page */
	30	struct page control_page; / Original page */
	31	} w;
	32	struct {
	33	struct bio *bio;
	34	struct work_struct work;
	35	} r;
	36	struct list_head free_list; /* Free list */
	37	};
	38	u8 flags; /* Flags */
	39	u8 mode; /* Encryption mode for tfm */
	40	};
	41
0b81d077 JK	42	/**
	43	* For encrypted symlinks, the ciphertext length is stored at the beginning
	44	* of the string in little-endian format.
	45	*/
	46	struct fscrypt_symlink_data {
	47	__le16 len;
	48	char encrypted_path[1];
	49	} __packed;
	50
	51	/**
	52	* This function is used to calculate the disk space required to
	53	* store a filename of length l in encrypted symlink format.
	54	*/
	55	static inline u32 fscrypt_symlink_data_len(u32 l)
	56	{
	57	if (l < FS_CRYPTO_BLOCK_SIZE)
	58	l = FS_CRYPTO_BLOCK_SIZE;
	59	return (l + sizeof(struct fscrypt_symlink_data) - 1);
	60	}
	61
	62	struct fscrypt_str {
	63	unsigned char *name;
	64	u32 len;
	65	};
	66
	67	struct fscrypt_name {
	68	const struct qstr *usr_fname;
	69	struct fscrypt_str disk_name;
	70	u32 hash;
	71	u32 minor_hash;
	72	struct fscrypt_str crypto_buf;
	73	};
	74
	75	#define FSTR_INIT(n, l) { .name = n, .len = l }
	76	#define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len)
	77	#define fname_name(p) ((p)->disk_name.name)
	78	#define fname_len(p) ((p)->disk_name.len)
	79
1c7dcf69 DG	80	/*
	81	* fscrypt superblock flags
	82	*/
	83	#define FS_CFLG_INPLACE_ENCRYPTION (1U << 1)
	84
0b81d077 JK	85	/*
	86	* crypto opertions for filesystems
	87	*/
	88	struct fscrypt_operations {
1c7dcf69	89	unsigned int flags;
0b81d077	90	int (get_context)(struct inode , void *, size_t);
b5a7aef1	91	int (key_prefix)(struct inode , u8 **);
0b81d077 JK	92	int (prepare_context)(struct inode );
	93	int (set_context)(struct inode , const void , size_t, void );
	94	int (dummy_context)(struct inode );
	95	bool (is_encrypted)(struct inode );
	96	bool (empty_dir)(struct inode );
	97	unsigned (max_namelen)(struct inode );
	98	};
	99
	100	static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
	101	{
	102	if (inode->i_sb->s_cop->dummy_context &&
	103	inode->i_sb->s_cop->dummy_context(inode))
	104	return true;
	105	return false;
	106	}
	107
	108	static inline bool fscrypt_valid_contents_enc_mode(u32 mode)
	109	{
	110	return (mode == FS_ENCRYPTION_MODE_AES_256_XTS);
	111	}
	112
	113	static inline bool fscrypt_valid_filenames_enc_mode(u32 mode)
	114	{
	115	return (mode == FS_ENCRYPTION_MODE_AES_256_CTS);
	116	}
	117
0b81d077 JK	118	static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
	119	{
	120	if (str->len == 1 && str->name[0] == '.')
	121	return true;
	122
	123	if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
	124	return true;
	125
	126	return false;
	127	}
	128
	129	static inline struct page fscrypt_control_page(struct page page)
	130	{
	131	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	132	return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
	133	#else
	134	WARN_ON_ONCE(1);
	135	return ERR_PTR(-EINVAL);
	136	#endif
	137	}
	138
0b93e1b9	139	static inline int fscrypt_has_encryption_key(const struct inode *inode)
0b81d077 JK	140	{
	141	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	142	return (inode->i_crypt_info != NULL);
	143	#else
	144	return 0;
	145	#endif
	146	}
	147
	148	static inline void fscrypt_set_encrypted_dentry(struct dentry *dentry)
	149	{
	150	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	151	spin_lock(&dentry->d_lock);
	152	dentry->d_flags \|= DCACHE_ENCRYPTED_WITH_KEY;
	153	spin_unlock(&dentry->d_lock);
	154	#endif
	155	}
	156
	157	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	158	extern const struct dentry_operations fscrypt_d_ops;
	159	#endif
	160
	161	static inline void fscrypt_set_d_op(struct dentry *dentry)
	162	{
	163	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	164	d_set_d_op(dentry, &fscrypt_d_ops);
	165	#endif
	166	}
	167
	168	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	169	/* crypto.c */
	170	extern struct kmem_cache *fscrypt_info_cachep;
0b81d077	171
0b93e1b9	172	extern struct fscrypt_ctx fscrypt_get_ctx(const struct inode , gfp_t);
0b81d077	173	extern void fscrypt_release_ctx(struct fscrypt_ctx *);
0b93e1b9	174	extern struct page fscrypt_encrypt_page(const struct inode , struct page *,
7821d4dd	175	unsigned int, unsigned int,
9c4bb8a3	176	pgoff_t, gfp_t);
0b93e1b9	177	extern int fscrypt_decrypt_page(const struct inode , struct page , unsigned int,
9c4bb8a3	178	unsigned int, pgoff_t);
0b81d077 JK	179	extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx , struct bio );
	180	extern void fscrypt_pullback_bio_page(struct page **, bool);
	181	extern void fscrypt_restore_control_page(struct page *);
0b93e1b9	182	extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
0b81d077 JK	183	unsigned int);
0b81d077 JK	184	/* policy.c */
db717d8e EB	185	extern int fscrypt_ioctl_set_policy(struct file , const void __user );
db717d8e EB	186	extern int fscrypt_ioctl_get_policy(struct file , void __user );
0b81d077 JK	187	extern int fscrypt_has_permitted_context(struct inode , struct inode );
	188	extern int fscrypt_inherit_context(struct inode , struct inode ,
	189	void *, bool);
	190	/* keyinfo.c */
0b81d077 JK	191	extern int fscrypt_get_encryption_info(struct inode *);
	192	extern void fscrypt_put_encryption_info(struct inode , struct fscrypt_info );
	193
	194	/* fname.c */
	195	extern int fscrypt_setup_filename(struct inode , const struct qstr ,
	196	int lookup, struct fscrypt_name *);
	197	extern void fscrypt_free_filename(struct fscrypt_name *);
0b93e1b9 DG	198	extern u32 fscrypt_fname_encrypted_size(const struct inode *, u32);
0b93e1b9 DG	199	extern int fscrypt_fname_alloc_buffer(const struct inode *, u32,
0b81d077 JK	200	struct fscrypt_str *);
	201	extern void fscrypt_fname_free_buffer(struct fscrypt_str *);
	202	extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
	203	const struct fscrypt_str , struct fscrypt_str );
	204	extern int fscrypt_fname_usr_to_disk(struct inode , const struct qstr ,
	205	struct fscrypt_str *);
	206	#endif
	207
	208	/* crypto.c */
0b93e1b9	209	static inline struct fscrypt_ctx fscrypt_notsupp_get_ctx(const struct inode i,
b32e4482	210	gfp_t f)
0b81d077 JK	211	{
	212	return ERR_PTR(-EOPNOTSUPP);
	213	}
	214
	215	static inline void fscrypt_notsupp_release_ctx(struct fscrypt_ctx *c)
	216	{
	217	return;
	218	}
	219
0b93e1b9	220	static inline struct page fscrypt_notsupp_encrypt_page(const struct inode i,
7821d4dd DG	221	struct page *p,
	222	unsigned int len,
	223	unsigned int offs,
9c4bb8a3	224	pgoff_t index, gfp_t f)
0b81d077 JK	225	{
	226	return ERR_PTR(-EOPNOTSUPP);
	227	}
	228
0b93e1b9	229	static inline int fscrypt_notsupp_decrypt_page(const struct inode i, struct page p,
9c4bb8a3 DG	230	unsigned int len, unsigned int offs,
9c4bb8a3 DG	231	pgoff_t index)
0b81d077 JK	232	{
	233	return -EOPNOTSUPP;
	234	}
	235
	236	static inline void fscrypt_notsupp_decrypt_bio_pages(struct fscrypt_ctx *c,
	237	struct bio *b)
	238	{
	239	return;
	240	}
	241
	242	static inline void fscrypt_notsupp_pullback_bio_page(struct page **p, bool b)
	243	{
	244	return;
	245	}
	246
	247	static inline void fscrypt_notsupp_restore_control_page(struct page *p)
	248	{
	249	return;
	250	}
	251
0b93e1b9	252	static inline int fscrypt_notsupp_zeroout_range(const struct inode *i, pgoff_t p,
0b81d077 JK	253	sector_t s, unsigned int f)
	254	{
	255	return -EOPNOTSUPP;
	256	}
	257
	258	/* policy.c */
db717d8e EB	259	static inline int fscrypt_notsupp_ioctl_set_policy(struct file *f,
db717d8e EB	260	const void __user *arg)
0b81d077 JK	261	{
	262	return -EOPNOTSUPP;
	263	}
	264
db717d8e EB	265	static inline int fscrypt_notsupp_ioctl_get_policy(struct file *f,
db717d8e EB	266	void __user *arg)
0b81d077 JK	267	{
	268	return -EOPNOTSUPP;
	269	}
	270
	271	static inline int fscrypt_notsupp_has_permitted_context(struct inode *p,
	272	struct inode *i)
	273	{
	274	return 0;
	275	}
	276
	277	static inline int fscrypt_notsupp_inherit_context(struct inode *p,
	278	struct inode i, void v, bool b)
	279	{
	280	return -EOPNOTSUPP;
	281	}
	282
	283	/* keyinfo.c */
	284	static inline int fscrypt_notsupp_get_encryption_info(struct inode *i)
	285	{
	286	return -EOPNOTSUPP;
	287	}
	288
	289	static inline void fscrypt_notsupp_put_encryption_info(struct inode *i,
	290	struct fscrypt_info *f)
	291	{
	292	return;
	293	}
	294
	295	/* fname.c */
	296	static inline int fscrypt_notsupp_setup_filename(struct inode *dir,
	297	const struct qstr *iname,
	298	int lookup, struct fscrypt_name *fname)
	299	{
	300	if (dir->i_sb->s_cop->is_encrypted(dir))
	301	return -EOPNOTSUPP;
	302
	303	memset(fname, 0, sizeof(struct fscrypt_name));
	304	fname->usr_fname = iname;
	305	fname->disk_name.name = (unsigned char *)iname->name;
	306	fname->disk_name.len = iname->len;
	307	return 0;
	308	}
	309
	310	static inline void fscrypt_notsupp_free_filename(struct fscrypt_name *fname)
	311	{
	312	return;
	313	}
	314
	315	static inline u32 fscrypt_notsupp_fname_encrypted_size(struct inode *i, u32 s)
	316	{
	317	/* never happens */
	318	WARN_ON(1);
	319	return 0;
	320	}
	321
	322	static inline int fscrypt_notsupp_fname_alloc_buffer(struct inode *inode,
	323	u32 ilen, struct fscrypt_str *crypto_str)
	324	{
	325	return -EOPNOTSUPP;
	326	}
	327
	328	static inline void fscrypt_notsupp_fname_free_buffer(struct fscrypt_str *c)
	329	{
	330	return;
331	}
332
333	static inline int fscrypt_notsupp_fname_disk_to_usr(struct inode *inode,
334	u32 hash, u32 minor_hash,
335	const struct fscrypt_str *iname,
336	struct fscrypt_str *oname)
337	{
338	return -EOPNOTSUPP;
339	}
340
341	static inline int fscrypt_notsupp_fname_usr_to_disk(struct inode *inode,
342	const struct qstr *iname,
343	struct fscrypt_str *oname)
344	{
345	return -EOPNOTSUPP;
346	}
347	#endif /* _LINUX_FSCRYPTO_H */