[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 {
	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_OWN_PAGES (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,
						u64, gfp_t);
extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int,
				unsigned int, u64);
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,
						u64 lblk_num, 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,
						u64 lblk_num)
{
	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	23	struct fscrypt_info;
0b81d077 JK	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	u8 mode; /* Encryption mode for tfm */
	39	};
	40
0b81d077 JK	41	/**
	42	* For encrypted symlinks, the ciphertext length is stored at the beginning
	43	* of the string in little-endian format.
	44	*/
	45	struct fscrypt_symlink_data {
	46	__le16 len;
	47	char encrypted_path[1];
	48	} __packed;
	49
	50	/**
	51	* This function is used to calculate the disk space required to
	52	* store a filename of length l in encrypted symlink format.
	53	*/
	54	static inline u32 fscrypt_symlink_data_len(u32 l)
	55	{
	56	if (l < FS_CRYPTO_BLOCK_SIZE)
	57	l = FS_CRYPTO_BLOCK_SIZE;
	58	return (l + sizeof(struct fscrypt_symlink_data) - 1);
	59	}
	60
	61	struct fscrypt_str {
	62	unsigned char *name;
	63	u32 len;
	64	};
	65
	66	struct fscrypt_name {
	67	const struct qstr *usr_fname;
	68	struct fscrypt_str disk_name;
	69	u32 hash;
	70	u32 minor_hash;
	71	struct fscrypt_str crypto_buf;
	72	};
	73
	74	#define FSTR_INIT(n, l) { .name = n, .len = l }
	75	#define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len)
	76	#define fname_name(p) ((p)->disk_name.name)
	77	#define fname_len(p) ((p)->disk_name.len)
	78
1c7dcf69 DG	79	/*
	80	* fscrypt superblock flags
	81	*/
bd7b8290	82	#define FS_CFLG_OWN_PAGES (1U << 1)
1c7dcf69	83
0b81d077 JK	84	/*
	85	* crypto opertions for filesystems
	86	*/
	87	struct fscrypt_operations {
1c7dcf69	88	unsigned int flags;
0b81d077	89	int (get_context)(struct inode , void *, size_t);
b5a7aef1	90	int (key_prefix)(struct inode , u8 **);
0b81d077 JK	91	int (prepare_context)(struct inode );
	92	int (set_context)(struct inode , const void , size_t, void );
	93	int (dummy_context)(struct inode );
	94	bool (is_encrypted)(struct inode );
	95	bool (empty_dir)(struct inode );
	96	unsigned (max_namelen)(struct inode );
	97	};
	98
	99	static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
	100	{
	101	if (inode->i_sb->s_cop->dummy_context &&
	102	inode->i_sb->s_cop->dummy_context(inode))
	103	return true;
	104	return false;
	105	}
	106
	107	static inline bool fscrypt_valid_contents_enc_mode(u32 mode)
	108	{
	109	return (mode == FS_ENCRYPTION_MODE_AES_256_XTS);
	110	}
	111
	112	static inline bool fscrypt_valid_filenames_enc_mode(u32 mode)
	113	{
	114	return (mode == FS_ENCRYPTION_MODE_AES_256_CTS);
	115	}
	116
0b81d077 JK	117	static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
	118	{
	119	if (str->len == 1 && str->name[0] == '.')
	120	return true;
	121
	122	if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
	123	return true;
	124
	125	return false;
	126	}
	127
	128	static inline struct page fscrypt_control_page(struct page page)
	129	{
	130	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	131	return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
	132	#else
	133	WARN_ON_ONCE(1);
	134	return ERR_PTR(-EINVAL);
	135	#endif
	136	}
	137
0b93e1b9	138	static inline int fscrypt_has_encryption_key(const struct inode *inode)
0b81d077 JK	139	{
	140	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	141	return (inode->i_crypt_info != NULL);
	142	#else
	143	return 0;
	144	#endif
	145	}
	146
	147	static inline void fscrypt_set_encrypted_dentry(struct dentry *dentry)
	148	{
	149	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	150	spin_lock(&dentry->d_lock);
	151	dentry->d_flags \|= DCACHE_ENCRYPTED_WITH_KEY;
	152	spin_unlock(&dentry->d_lock);
	153	#endif
	154	}
	155
	156	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	157	extern const struct dentry_operations fscrypt_d_ops;
	158	#endif
	159
	160	static inline void fscrypt_set_d_op(struct dentry *dentry)
	161	{
	162	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	163	d_set_d_op(dentry, &fscrypt_d_ops);
	164	#endif
	165	}
	166
	167	#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
	168	/* crypto.c */
	169	extern struct kmem_cache *fscrypt_info_cachep;
0b93e1b9	170	extern struct fscrypt_ctx fscrypt_get_ctx(const struct inode , gfp_t);
0b81d077	171	extern void fscrypt_release_ctx(struct fscrypt_ctx *);
0b93e1b9	172	extern struct page fscrypt_encrypt_page(const struct inode , struct page *,
7821d4dd	173	unsigned int, unsigned int,
1400451f	174	u64, gfp_t);
0b93e1b9	175	extern int fscrypt_decrypt_page(const struct inode , struct page , unsigned int,
1400451f	176	unsigned int, u64);
0b81d077 JK	177	extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx , struct bio );
	178	extern void fscrypt_pullback_bio_page(struct page **, bool);
	179	extern void fscrypt_restore_control_page(struct page *);
0b93e1b9	180	extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
0b81d077 JK	181	unsigned int);
0b81d077 JK	182	/* policy.c */
db717d8e EB	183	extern int fscrypt_ioctl_set_policy(struct file , const void __user );
db717d8e EB	184	extern int fscrypt_ioctl_get_policy(struct file , void __user );
0b81d077 JK	185	extern int fscrypt_has_permitted_context(struct inode , struct inode );
	186	extern int fscrypt_inherit_context(struct inode , struct inode ,
	187	void *, bool);
	188	/* keyinfo.c */
0b81d077 JK	189	extern int fscrypt_get_encryption_info(struct inode *);
	190	extern void fscrypt_put_encryption_info(struct inode , struct fscrypt_info );
	191
	192	/* fname.c */
	193	extern int fscrypt_setup_filename(struct inode , const struct qstr ,
	194	int lookup, struct fscrypt_name *);
	195	extern void fscrypt_free_filename(struct fscrypt_name *);
0b93e1b9 DG	196	extern u32 fscrypt_fname_encrypted_size(const struct inode *, u32);
0b93e1b9 DG	197	extern int fscrypt_fname_alloc_buffer(const struct inode *, u32,
0b81d077 JK	198	struct fscrypt_str *);
	199	extern void fscrypt_fname_free_buffer(struct fscrypt_str *);
	200	extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
	201	const struct fscrypt_str , struct fscrypt_str );
	202	extern int fscrypt_fname_usr_to_disk(struct inode , const struct qstr ,
	203	struct fscrypt_str *);
	204	#endif
	205
	206	/* crypto.c */
0b93e1b9	207	static inline struct fscrypt_ctx fscrypt_notsupp_get_ctx(const struct inode i,
b32e4482	208	gfp_t f)
0b81d077 JK	209	{
	210	return ERR_PTR(-EOPNOTSUPP);
	211	}
	212
	213	static inline void fscrypt_notsupp_release_ctx(struct fscrypt_ctx *c)
	214	{
	215	return;
	216	}
	217
0b93e1b9	218	static inline struct page fscrypt_notsupp_encrypt_page(const struct inode i,
7821d4dd DG	219	struct page *p,
	220	unsigned int len,
	221	unsigned int offs,
1400451f	222	u64 lblk_num, gfp_t f)
0b81d077 JK	223	{
	224	return ERR_PTR(-EOPNOTSUPP);
	225	}
	226
0b93e1b9	227	static inline int fscrypt_notsupp_decrypt_page(const struct inode i, struct page p,
9c4bb8a3	228	unsigned int len, unsigned int offs,
1400451f	229	u64 lblk_num)
0b81d077 JK	230	{
	231	return -EOPNOTSUPP;
	232	}
	233
	234	static inline void fscrypt_notsupp_decrypt_bio_pages(struct fscrypt_ctx *c,
	235	struct bio *b)
	236	{
	237	return;
	238	}
	239
	240	static inline void fscrypt_notsupp_pullback_bio_page(struct page **p, bool b)
	241	{
	242	return;
	243	}
	244
	245	static inline void fscrypt_notsupp_restore_control_page(struct page *p)
	246	{
	247	return;
	248	}
	249
0b93e1b9	250	static inline int fscrypt_notsupp_zeroout_range(const struct inode *i, pgoff_t p,
0b81d077 JK	251	sector_t s, unsigned int f)
	252	{
	253	return -EOPNOTSUPP;
	254	}
	255
	256	/* policy.c */
db717d8e EB	257	static inline int fscrypt_notsupp_ioctl_set_policy(struct file *f,
db717d8e EB	258	const void __user *arg)
0b81d077 JK	259	{
	260	return -EOPNOTSUPP;
	261	}
	262
db717d8e EB	263	static inline int fscrypt_notsupp_ioctl_get_policy(struct file *f,
db717d8e EB	264	void __user *arg)
0b81d077 JK	265	{
	266	return -EOPNOTSUPP;
	267	}
	268
	269	static inline int fscrypt_notsupp_has_permitted_context(struct inode *p,
	270	struct inode *i)
	271	{
	272	return 0;
	273	}
	274
	275	static inline int fscrypt_notsupp_inherit_context(struct inode *p,
	276	struct inode i, void v, bool b)
	277	{
	278	return -EOPNOTSUPP;
	279	}
	280
	281	/* keyinfo.c */
	282	static inline int fscrypt_notsupp_get_encryption_info(struct inode *i)
	283	{
	284	return -EOPNOTSUPP;
	285	}
	286
	287	static inline void fscrypt_notsupp_put_encryption_info(struct inode *i,
	288	struct fscrypt_info *f)
	289	{
	290	return;
	291	}
	292
	293	/* fname.c */
	294	static inline int fscrypt_notsupp_setup_filename(struct inode *dir,
	295	const struct qstr *iname,
	296	int lookup, struct fscrypt_name *fname)
	297	{
	298	if (dir->i_sb->s_cop->is_encrypted(dir))
	299	return -EOPNOTSUPP;
	300
	301	memset(fname, 0, sizeof(struct fscrypt_name));
	302	fname->usr_fname = iname;
	303	fname->disk_name.name = (unsigned char *)iname->name;
	304	fname->disk_name.len = iname->len;
	305	return 0;
	306	}
	307
	308	static inline void fscrypt_notsupp_free_filename(struct fscrypt_name *fname)
	309	{
	310	return;
	311	}
	312
	313	static inline u32 fscrypt_notsupp_fname_encrypted_size(struct inode *i, u32 s)
	314	{
	315	/* never happens */
	316	WARN_ON(1);
	317	return 0;
	318	}
	319
	320	static inline int fscrypt_notsupp_fname_alloc_buffer(struct inode *inode,
	321	u32 ilen, struct fscrypt_str *crypto_str)
	322	{
	323	return -EOPNOTSUPP;
	324	}
	325
	326	static inline void fscrypt_notsupp_fname_free_buffer(struct fscrypt_str *c)
	327	{
	328	return;
329	}
330
331	static inline int fscrypt_notsupp_fname_disk_to_usr(struct inode *inode,
332	u32 hash, u32 minor_hash,
333	const struct fscrypt_str *iname,
334	struct fscrypt_str *oname)
335	{
336	return -EOPNOTSUPP;
337	}
338
339	static inline int fscrypt_notsupp_fname_usr_to_disk(struct inode *inode,
340	const struct qstr *iname,
341	struct fscrypt_str *oname)
342	{
343	return -EOPNOTSUPP;
344	}
345	#endif /* _LINUX_FSCRYPTO_H */