[linux-2.6-block.git] / fs / readdir.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/readdir.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 */

#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/dirent.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/compat.h>
#include <linux/uaccess.h>

#include <asm/unaligned.h>

/*
 * Note the "unsafe_put_user() semantics: we goto a
 * label for errors.
 */
#define unsafe_copy_dirent_name(_dst, _src, _len, label) do {	\
	char __user *dst = (_dst);				\
	const char *src = (_src);				\
	size_t len = (_len);					\
	unsafe_put_user(0, dst+len, label);			\
	unsafe_copy_to_user(dst, src, len, label);		\
} while (0)


int iterate_dir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	bool shared = false;
	int res = -ENOTDIR;
	if (file->f_op->iterate_shared)
		shared = true;
	else if (!file->f_op->iterate)
		goto out;

	res = security_file_permission(file, MAY_READ);
	if (res)
		goto out;

	if (shared)
		res = down_read_killable(&inode->i_rwsem);
	else
		res = down_write_killable(&inode->i_rwsem);
	if (res)
		goto out;

	res = -ENOENT;
	if (!IS_DEADDIR(inode)) {
		ctx->pos = file->f_pos;
		if (shared)
			res = file->f_op->iterate_shared(file, ctx);
		else
			res = file->f_op->iterate(file, ctx);
		file->f_pos = ctx->pos;
		fsnotify_access(file);
		file_accessed(file);
	}
	if (shared)
		inode_unlock_shared(inode);
	else
		inode_unlock(inode);
out:
	return res;
}
EXPORT_SYMBOL(iterate_dir);

/*
 * POSIX says that a dirent name cannot contain NULL or a '/'.
 *
 * It's not 100% clear what we should really do in this case.
 * The filesystem is clearly corrupted, but returning a hard
 * error means that you now don't see any of the other names
 * either, so that isn't a perfect alternative.
 *
 * And if you return an error, what error do you use? Several
 * filesystems seem to have decided on EUCLEAN being the error
 * code for EFSCORRUPTED, and that may be the error to use. Or
 * just EIO, which is perhaps more obvious to users.
 *
 * In order to see the other file names in the directory, the
 * caller might want to make this a "soft" error: skip the
 * entry, and return the error at the end instead.
 *
 * Note that this should likely do a "memchr(name, 0, len)"
 * check too, since that would be filesystem corruption as
 * well. However, that case can't actually confuse user space,
 * which has to do a strlen() on the name anyway to find the
 * filename length, and the above "soft error" worry means
 * that it's probably better left alone until we have that
 * issue clarified.
 */
static int verify_dirent_name(const char *name, int len)
{
	if (!len)
		return -EIO;
	if (memchr(name, '/', len))
		return -EIO;
	return 0;
}

/*
 * Traditional linux readdir() handling..
 *
 * "count=1" is a special case, meaning that the buffer is one
 * dirent-structure in size and that the code can't handle more
 * anyway. Thus the special "fillonedir()" function for that
 * case (the low-level handlers don't need to care about this).
 */

#ifdef __ARCH_WANT_OLD_READDIR

struct old_linux_dirent {
	unsigned long	d_ino;
	unsigned long	d_offset;
	unsigned short	d_namlen;
	char		d_name[1];
};

struct readdir_callback {
	struct dir_context ctx;
	struct old_linux_dirent __user * dirent;
	int result;
};

static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
		      loff_t offset, u64 ino, unsigned int d_type)
{
	struct readdir_callback *buf =
		container_of(ctx, struct readdir_callback, ctx);
	struct old_linux_dirent __user * dirent;
	unsigned long d_ino;

	if (buf->result)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->result = -EOVERFLOW;
		return -EOVERFLOW;
	}
	buf->result++;
	dirent = buf->dirent;
	if (!access_ok(dirent,
			(unsigned long)(dirent->d_name + namlen + 1) -
				(unsigned long)dirent))
		goto efault;
	if (	__put_user(d_ino, &dirent->d_ino) ||
		__put_user(offset, &dirent->d_offset) ||
		__put_user(namlen, &dirent->d_namlen) ||
		__copy_to_user(dirent->d_name, name, namlen) ||
		__put_user(0, dirent->d_name + namlen))
		goto efault;
	return 0;
efault:
	buf->result = -EFAULT;
	return -EFAULT;
}

SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
		struct old_linux_dirent __user *, dirent, unsigned int, count)
{
	int error;
	struct fd f = fdget_pos(fd);
	struct readdir_callback buf = {
		.ctx.actor = fillonedir,
		.dirent = dirent
	};

	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (buf.result)
		error = buf.result;

	fdput_pos(f);
	return error;
}

#endif /* __ARCH_WANT_OLD_READDIR */

/*
 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
 * interface. 
 */
struct linux_dirent {
	unsigned long	d_ino;
	unsigned long	d_off;
	unsigned short	d_reclen;
	char		d_name[1];
};

struct getdents_callback {
	struct dir_context ctx;
	struct linux_dirent __user * current_dir;
	struct linux_dirent __user * previous;
	int count;
	int error;
};

static int filldir(struct dir_context *ctx, const char *name, int namlen,
		   loff_t offset, u64 ino, unsigned int d_type)
{
	struct linux_dirent __user * dirent;
	struct getdents_callback *buf =
		container_of(ctx, struct getdents_callback, ctx);
	unsigned long d_ino;
	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
		sizeof(long));

	buf->error = verify_dirent_name(name, namlen);
	if (unlikely(buf->error))
		return buf->error;
	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->error = -EOVERFLOW;
		return -EOVERFLOW;
	}
	dirent = buf->previous;
	if (dirent && signal_pending(current))
		return -EINTR;

	/*
	 * Note! This range-checks 'previous' (which may be NULL).
	 * The real range was checked in getdents
	 */
	if (!user_access_begin(dirent, sizeof(*dirent)))
		goto efault;
	if (dirent)
		unsafe_put_user(offset, &dirent->d_off, efault_end);
	dirent = buf->current_dir;
	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	user_access_end();

	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault_end:
	user_access_end();
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

SYSCALL_DEFINE3(getdents, unsigned int, fd,
		struct linux_dirent __user *, dirent, unsigned int, count)
{
	struct fd f;
	struct linux_dirent __user * lastdirent;
	struct getdents_callback buf = {
		.ctx.actor = filldir,
		.count = count,
		.current_dir = dirent
	};
	int error;

	if (!access_ok(dirent, count))
		return -EFAULT;

	f = fdget_pos(fd);
	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		if (put_user(buf.ctx.pos, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}
	fdput_pos(f);
	return error;
}

struct getdents_callback64 {
	struct dir_context ctx;
	struct linux_dirent64 __user * current_dir;
	struct linux_dirent64 __user * previous;
	int count;
	int error;
};

static int filldir64(struct dir_context *ctx, const char *name, int namlen,
		     loff_t offset, u64 ino, unsigned int d_type)
{
	struct linux_dirent64 __user *dirent;
	struct getdents_callback64 *buf =
		container_of(ctx, struct getdents_callback64, ctx);
	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
		sizeof(u64));

	buf->error = verify_dirent_name(name, namlen);
	if (unlikely(buf->error))
		return buf->error;
	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	dirent = buf->previous;
	if (dirent && signal_pending(current))
		return -EINTR;

	/*
	 * Note! This range-checks 'previous' (which may be NULL).
	 * The real range was checked in getdents
	 */
	if (!user_access_begin(dirent, sizeof(*dirent)))
		goto efault;
	if (dirent)
		unsafe_put_user(offset, &dirent->d_off, efault_end);
	dirent = buf->current_dir;
	unsafe_put_user(ino, &dirent->d_ino, efault_end);
	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	unsafe_put_user(d_type, &dirent->d_type, efault_end);
	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	user_access_end();

	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault_end:
	user_access_end();
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
		    unsigned int count)
{
	struct fd f;
	struct linux_dirent64 __user * lastdirent;
	struct getdents_callback64 buf = {
		.ctx.actor = filldir64,
		.count = count,
		.current_dir = dirent
	};
	int error;

	if (!access_ok(dirent, count))
		return -EFAULT;

	f = fdget_pos(fd);
	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		typeof(lastdirent->d_off) d_off = buf.ctx.pos;
		if (__put_user(d_off, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}
	fdput_pos(f);
	return error;
}


SYSCALL_DEFINE3(getdents64, unsigned int, fd,
		struct linux_dirent64 __user *, dirent, unsigned int, count)
{
	return ksys_getdents64(fd, dirent, count);
}

#ifdef CONFIG_COMPAT
struct compat_old_linux_dirent {
	compat_ulong_t	d_ino;
	compat_ulong_t	d_offset;
	unsigned short	d_namlen;
	char		d_name[1];
};

struct compat_readdir_callback {
	struct dir_context ctx;
	struct compat_old_linux_dirent __user *dirent;
	int result;
};

static int compat_fillonedir(struct dir_context *ctx, const char *name,
			     int namlen, loff_t offset, u64 ino,
			     unsigned int d_type)
{
	struct compat_readdir_callback *buf =
		container_of(ctx, struct compat_readdir_callback, ctx);
	struct compat_old_linux_dirent __user *dirent;
	compat_ulong_t d_ino;

	if (buf->result)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->result = -EOVERFLOW;
		return -EOVERFLOW;
	}
	buf->result++;
	dirent = buf->dirent;
	if (!access_ok(dirent,
			(unsigned long)(dirent->d_name + namlen + 1) -
				(unsigned long)dirent))
		goto efault;
	if (	__put_user(d_ino, &dirent->d_ino) ||
		__put_user(offset, &dirent->d_offset) ||
		__put_user(namlen, &dirent->d_namlen) ||
		__copy_to_user(dirent->d_name, name, namlen) ||
		__put_user(0, dirent->d_name + namlen))
		goto efault;
	return 0;
efault:
	buf->result = -EFAULT;
	return -EFAULT;
}

COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
		struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
{
	int error;
	struct fd f = fdget_pos(fd);
	struct compat_readdir_callback buf = {
		.ctx.actor = compat_fillonedir,
		.dirent = dirent
	};

	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (buf.result)
		error = buf.result;

	fdput_pos(f);
	return error;
}

struct compat_linux_dirent {
	compat_ulong_t	d_ino;
	compat_ulong_t	d_off;
	unsigned short	d_reclen;
	char		d_name[1];
};

struct compat_getdents_callback {
	struct dir_context ctx;
	struct compat_linux_dirent __user *current_dir;
	struct compat_linux_dirent __user *previous;
	int count;
	int error;
};

static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
		loff_t offset, u64 ino, unsigned int d_type)
{
	struct compat_linux_dirent __user * dirent;
	struct compat_getdents_callback *buf =
		container_of(ctx, struct compat_getdents_callback, ctx);
	compat_ulong_t d_ino;
	int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
		namlen + 2, sizeof(compat_long_t));

	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->error = -EOVERFLOW;
		return -EOVERFLOW;
	}
	dirent = buf->previous;
	if (dirent) {
		if (signal_pending(current))
			return -EINTR;
		if (__put_user(offset, &dirent->d_off))
			goto efault;
	}
	dirent = buf->current_dir;
	if (__put_user(d_ino, &dirent->d_ino))
		goto efault;
	if (__put_user(reclen, &dirent->d_reclen))
		goto efault;
	if (copy_to_user(dirent->d_name, name, namlen))
		goto efault;
	if (__put_user(0, dirent->d_name + namlen))
		goto efault;
	if (__put_user(d_type, (char  __user *) dirent + reclen - 1))
		goto efault;
	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
		struct compat_linux_dirent __user *, dirent, unsigned int, count)
{
	struct fd f;
	struct compat_linux_dirent __user * lastdirent;
	struct compat_getdents_callback buf = {
		.ctx.actor = compat_filldir,
		.current_dir = dirent,
		.count = count
	};
	int error;

	if (!access_ok(dirent, count))
		return -EFAULT;

	f = fdget_pos(fd);
	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		if (put_user(buf.ctx.pos, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}
	fdput_pos(f);
	return error;
}
#endif
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/readdir.c
	4	*
	5	* Copyright (C) 1995 Linus Torvalds
	6	*/
	7
85c9fe8f	8	#include <linux/stddef.h>
022a1692	9	#include <linux/kernel.h>
630d9c47	10	#include <linux/export.h>
1da177e4 LT	11	#include <linux/time.h>
	12	#include <linux/mm.h>
	13	#include <linux/errno.h>
	14	#include <linux/stat.h>
	15	#include <linux/file.h>
1da177e4	16	#include <linux/fs.h>
d4c7cf6c	17	#include <linux/fsnotify.h>
1da177e4 LT	18	#include <linux/dirent.h>
	19	#include <linux/security.h>
	20	#include <linux/syscalls.h>
	21	#include <linux/unistd.h>
0460b2a2	22	#include <linux/compat.h>
7c0f6ba6	23	#include <linux/uaccess.h>
1da177e4	24
9f79b78e LT	25	#include <asm/unaligned.h>
	26
	27	/*
	28	* Note the "unsafe_put_user() semantics: we goto a
	29	* label for errors.
9f79b78e LT	30	*/
	31	#define unsafe_copy_dirent_name(_dst, _src, _len, label) do { \
	32	char __user *dst = (_dst); \
	33	const char *src = (_src); \
	34	size_t len = (_len); \
c512c691 LT	35	unsafe_put_user(0, dst+len, label); \
c512c691 LT	36	unsafe_copy_to_user(dst, src, len, label); \
9f79b78e LT	37	} while (0)
	38
	39
5c0ba4e0	40	int iterate_dir(struct file file, struct dir_context ctx)
1da177e4	41	{
496ad9aa	42	struct inode *inode = file_inode(file);
61922694	43	bool shared = false;
1da177e4	44	int res = -ENOTDIR;
61922694 AV	45	if (file->f_op->iterate_shared)
	46	shared = true;
	47	else if (!file->f_op->iterate)
1da177e4 LT	48	goto out;
	49
	50	res = security_file_permission(file, MAY_READ);
	51	if (res)
	52	goto out;
	53
0dc208b5 KT	54	if (shared)
	55	res = down_read_killable(&inode->i_rwsem);
	56	else
00235411	57	res = down_write_killable(&inode->i_rwsem);
0dc208b5 KT	58	if (res)
0dc208b5 KT	59	goto out;
da784511	60
1da177e4 LT	61	res = -ENOENT;
1da177e4 LT	62	if (!IS_DEADDIR(inode)) {
2233f31a	63	ctx->pos = file->f_pos;
61922694 AV	64	if (shared)
	65	res = file->f_op->iterate_shared(file, ctx);
	66	else
	67	res = file->f_op->iterate(file, ctx);
2233f31a	68	file->f_pos = ctx->pos;
d4c7cf6c	69	fsnotify_access(file);
1da177e4 LT	70	file_accessed(file);
1da177e4 LT	71	}
61922694 AV	72	if (shared)
	73	inode_unlock_shared(inode);
	74	else
	75	inode_unlock(inode);
1da177e4 LT	76	out:
	77	return res;
	78	}
5c0ba4e0	79	EXPORT_SYMBOL(iterate_dir);
1da177e4	80
8a23eb80 LT	81	/*
	82	* POSIX says that a dirent name cannot contain NULL or a '/'.
	83	*
	84	* It's not 100% clear what we should really do in this case.
	85	* The filesystem is clearly corrupted, but returning a hard
	86	* error means that you now don't see any of the other names
	87	* either, so that isn't a perfect alternative.
	88	*
	89	* And if you return an error, what error do you use? Several
	90	* filesystems seem to have decided on EUCLEAN being the error
	91	* code for EFSCORRUPTED, and that may be the error to use. Or
	92	* just EIO, which is perhaps more obvious to users.
	93	*
	94	* In order to see the other file names in the directory, the
	95	* caller might want to make this a "soft" error: skip the
	96	* entry, and return the error at the end instead.
	97	*
	98	* Note that this should likely do a "memchr(name, 0, len)"
	99	* check too, since that would be filesystem corruption as
	100	* well. However, that case can't actually confuse user space,
	101	* which has to do a strlen() on the name anyway to find the
	102	* filename length, and the above "soft error" worry means
	103	* that it's probably better left alone until we have that
	104	* issue clarified.
	105	*/
	106	static int verify_dirent_name(const char *name, int len)
	107	{
b9959c7a	108	if (!len)
8a23eb80	109	return -EIO;
b9959c7a	110	if (memchr(name, '/', len))
8a23eb80 LT	111	return -EIO;
	112	return 0;
	113	}
	114
1da177e4 LT	115	/*
	116	* Traditional linux readdir() handling..
	117	*
	118	* "count=1" is a special case, meaning that the buffer is one
	119	* dirent-structure in size and that the code can't handle more
	120	* anyway. Thus the special "fillonedir()" function for that
	121	* case (the low-level handlers don't need to care about this).
	122	*/
1da177e4 LT	123
	124	#ifdef __ARCH_WANT_OLD_READDIR
	125
	126	struct old_linux_dirent {
	127	unsigned long d_ino;
	128	unsigned long d_offset;
	129	unsigned short d_namlen;
	130	char d_name[1];
	131	};
	132
	133	struct readdir_callback {
5c0ba4e0	134	struct dir_context ctx;
1da177e4 LT	135	struct old_linux_dirent __user * dirent;
	136	int result;
	137	};
	138
ac7576f4 MS	139	static int fillonedir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	140	loff_t offset, u64 ino, unsigned int d_type)
1da177e4	141	{
ac7576f4 MS	142	struct readdir_callback *buf =
ac7576f4 MS	143	container_of(ctx, struct readdir_callback, ctx);
1da177e4	144	struct old_linux_dirent __user * dirent;
afefdbb2	145	unsigned long d_ino;
1da177e4 LT	146
	147	if (buf->result)
	148	return -EINVAL;
afefdbb2	149	d_ino = ino;
8f3f655d AV	150	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	151	buf->result = -EOVERFLOW;
afefdbb2	152	return -EOVERFLOW;
8f3f655d	153	}
1da177e4 LT	154	buf->result++;
1da177e4 LT	155	dirent = buf->dirent;
96d4f267	156	if (!access_ok(dirent,
1da177e4 LT	157	(unsigned long)(dirent->d_name + namlen + 1) -
	158	(unsigned long)dirent))
	159	goto efault;
afefdbb2	160	if ( __put_user(d_ino, &dirent->d_ino) \|\|
1da177e4 LT	161	__put_user(offset, &dirent->d_offset) \|\|
	162	__put_user(namlen, &dirent->d_namlen) \|\|
	163	__copy_to_user(dirent->d_name, name, namlen) \|\|
	164	__put_user(0, dirent->d_name + namlen))
	165	goto efault;
	166	return 0;
	167	efault:
	168	buf->result = -EFAULT;
	169	return -EFAULT;
	170	}
	171
d4e82042 HC	172	SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
d4e82042 HC	173	struct old_linux_dirent __user *, dirent, unsigned int, count)
1da177e4 LT	174	{
1da177e4 LT	175	int error;
63b6df14	176	struct fd f = fdget_pos(fd);
ac6614b7 AV	177	struct readdir_callback buf = {
	178	.ctx.actor = fillonedir,
	179	.dirent = dirent
	180	};
1da177e4	181
2903ff01	182	if (!f.file)
863ced7f	183	return -EBADF;
1da177e4	184
5c0ba4e0	185	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	186	if (buf.result)
1da177e4 LT	187	error = buf.result;
1da177e4 LT	188
63b6df14	189	fdput_pos(f);
1da177e4 LT	190	return error;
	191	}
	192
	193	#endif /* __ARCH_WANT_OLD_READDIR */
	194
	195	/*
	196	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	197	* interface.
	198	*/
	199	struct linux_dirent {
	200	unsigned long d_ino;
	201	unsigned long d_off;
	202	unsigned short d_reclen;
	203	char d_name[1];
	204	};
	205
	206	struct getdents_callback {
5c0ba4e0	207	struct dir_context ctx;
1da177e4 LT	208	struct linux_dirent __user * current_dir;
	209	struct linux_dirent __user * previous;
	210	int count;
	211	int error;
	212	};
	213
ac7576f4 MS	214	static int filldir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	215	loff_t offset, u64 ino, unsigned int d_type)
1da177e4 LT	216	{
1da177e4 LT	217	struct linux_dirent __user * dirent;
ac7576f4 MS	218	struct getdents_callback *buf =
ac7576f4 MS	219	container_of(ctx, struct getdents_callback, ctx);
afefdbb2	220	unsigned long d_ino;
85c9fe8f KW	221	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
85c9fe8f KW	222	sizeof(long));
1da177e4	223
8a23eb80 LT	224	buf->error = verify_dirent_name(name, namlen);
	225	if (unlikely(buf->error))
	226	return buf->error;
1da177e4 LT	227	buf->error = -EINVAL; /* only used if we fail.. */
	228	if (reclen > buf->count)
	229	return -EINVAL;
afefdbb2	230	d_ino = ino;
8f3f655d AV	231	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	232	buf->error = -EOVERFLOW;
afefdbb2	233	return -EOVERFLOW;
8f3f655d	234	}
1da177e4	235	dirent = buf->previous;
9f79b78e LT	236	if (dirent && signal_pending(current))
	237	return -EINTR;
	238
	239	/*
	240	* Note! This range-checks 'previous' (which may be NULL).
	241	* The real range was checked in getdents
	242	*/
	243	if (!user_access_begin(dirent, sizeof(*dirent)))
1da177e4	244	goto efault;
9f79b78e LT	245	if (dirent)
	246	unsafe_put_user(offset, &dirent->d_off, efault_end);
	247	dirent = buf->current_dir;
	248	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	249	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	250	unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
	251	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	252	user_access_end();
	253
1da177e4 LT	254	buf->previous = dirent;
	255	dirent = (void __user *)dirent + reclen;
	256	buf->current_dir = dirent;
	257	buf->count -= reclen;
	258	return 0;
9f79b78e LT	259	efault_end:
9f79b78e LT	260	user_access_end();
1da177e4 LT	261	efault:
	262	buf->error = -EFAULT;
	263	return -EFAULT;
	264	}
	265
20f37034 HC	266	SYSCALL_DEFINE3(getdents, unsigned int, fd,
20f37034 HC	267	struct linux_dirent __user *, dirent, unsigned int, count)
1da177e4	268	{
2903ff01	269	struct fd f;
1da177e4	270	struct linux_dirent __user * lastdirent;
ac6614b7 AV	271	struct getdents_callback buf = {
	272	.ctx.actor = filldir,
	273	.count = count,
	274	.current_dir = dirent
	275	};
1da177e4 LT	276	int error;
1da177e4 LT	277
96d4f267	278	if (!access_ok(dirent, count))
863ced7f	279	return -EFAULT;
1da177e4	280
63b6df14	281	f = fdget_pos(fd);
2903ff01	282	if (!f.file)
863ced7f	283	return -EBADF;
1da177e4	284
5c0ba4e0	285	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	286	if (error >= 0)
53c9c5c0 AV	287	error = buf.error;
1da177e4 LT	288	lastdirent = buf.previous;
1da177e4 LT	289	if (lastdirent) {
bb6f619b	290	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	291	error = -EFAULT;
	292	else
	293	error = count - buf.count;
	294	}
63b6df14	295	fdput_pos(f);
1da177e4 LT	296	return error;
	297	}
	298
1da177e4	299	struct getdents_callback64 {
5c0ba4e0	300	struct dir_context ctx;
1da177e4 LT	301	struct linux_dirent64 __user * current_dir;
	302	struct linux_dirent64 __user * previous;
	303	int count;
	304	int error;
	305	};
	306
ac7576f4 MS	307	static int filldir64(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	308	loff_t offset, u64 ino, unsigned int d_type)
1da177e4 LT	309	{
1da177e4 LT	310	struct linux_dirent64 __user *dirent;
ac7576f4 MS	311	struct getdents_callback64 *buf =
ac7576f4 MS	312	container_of(ctx, struct getdents_callback64, ctx);
85c9fe8f KW	313	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	314	sizeof(u64));
1da177e4	315
8a23eb80 LT	316	buf->error = verify_dirent_name(name, namlen);
	317	if (unlikely(buf->error))
	318	return buf->error;
1da177e4 LT	319	buf->error = -EINVAL; /* only used if we fail.. */
	320	if (reclen > buf->count)
	321	return -EINVAL;
	322	dirent = buf->previous;
9f79b78e LT	323	if (dirent && signal_pending(current))
	324	return -EINTR;
	325
	326	/*
	327	* Note! This range-checks 'previous' (which may be NULL).
	328	* The real range was checked in getdents
	329	*/
	330	if (!user_access_begin(dirent, sizeof(*dirent)))
1da177e4	331	goto efault;
9f79b78e LT	332	if (dirent)
	333	unsafe_put_user(offset, &dirent->d_off, efault_end);
	334	dirent = buf->current_dir;
	335	unsafe_put_user(ino, &dirent->d_ino, efault_end);
	336	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	337	unsafe_put_user(d_type, &dirent->d_type, efault_end);
	338	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	339	user_access_end();
	340
1da177e4 LT	341	buf->previous = dirent;
	342	dirent = (void __user *)dirent + reclen;
	343	buf->current_dir = dirent;
	344	buf->count -= reclen;
	345	return 0;
9f79b78e LT	346	efault_end:
9f79b78e LT	347	user_access_end();
1da177e4 LT	348	efault:
	349	buf->error = -EFAULT;
	350	return -EFAULT;
	351	}
	352
454dab3f DB	353	int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
454dab3f DB	354	unsigned int count)
1da177e4	355	{
2903ff01	356	struct fd f;
1da177e4	357	struct linux_dirent64 __user * lastdirent;
ac6614b7 AV	358	struct getdents_callback64 buf = {
	359	.ctx.actor = filldir64,
	360	.count = count,
	361	.current_dir = dirent
	362	};
1da177e4 LT	363	int error;
1da177e4 LT	364
96d4f267	365	if (!access_ok(dirent, count))
863ced7f	366	return -EFAULT;
1da177e4	367
63b6df14	368	f = fdget_pos(fd);
2903ff01	369	if (!f.file)
863ced7f	370	return -EBADF;
1da177e4	371
5c0ba4e0	372	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	373	if (error >= 0)
53c9c5c0 AV	374	error = buf.error;
1da177e4 LT	375	lastdirent = buf.previous;
1da177e4 LT	376	if (lastdirent) {
bb6f619b	377	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
1da177e4	378	if (__put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	379	error = -EFAULT;
	380	else
	381	error = count - buf.count;
1da177e4	382	}
63b6df14	383	fdput_pos(f);
1da177e4 LT	384	return error;
1da177e4 LT	385	}
0460b2a2	386
454dab3f DB	387
	388	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
	389	struct linux_dirent64 __user *, dirent, unsigned int, count)
	390	{
	391	return ksys_getdents64(fd, dirent, count);
	392	}
	393
0460b2a2 AV	394	#ifdef CONFIG_COMPAT
	395	struct compat_old_linux_dirent {
	396	compat_ulong_t d_ino;
	397	compat_ulong_t d_offset;
	398	unsigned short d_namlen;
	399	char d_name[1];
	400	};
	401
	402	struct compat_readdir_callback {
	403	struct dir_context ctx;
	404	struct compat_old_linux_dirent __user *dirent;
	405	int result;
	406	};
	407
	408	static int compat_fillonedir(struct dir_context ctx, const char name,
	409	int namlen, loff_t offset, u64 ino,
	410	unsigned int d_type)
	411	{
	412	struct compat_readdir_callback *buf =
	413	container_of(ctx, struct compat_readdir_callback, ctx);
	414	struct compat_old_linux_dirent __user *dirent;
	415	compat_ulong_t d_ino;
	416
	417	if (buf->result)
	418	return -EINVAL;
	419	d_ino = ino;
	420	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
	421	buf->result = -EOVERFLOW;
	422	return -EOVERFLOW;
	423	}
	424	buf->result++;
	425	dirent = buf->dirent;
96d4f267	426	if (!access_ok(dirent,
0460b2a2 AV	427	(unsigned long)(dirent->d_name + namlen + 1) -
	428	(unsigned long)dirent))
	429	goto efault;
	430	if ( __put_user(d_ino, &dirent->d_ino) \|\|
	431	__put_user(offset, &dirent->d_offset) \|\|
	432	__put_user(namlen, &dirent->d_namlen) \|\|
	433	__copy_to_user(dirent->d_name, name, namlen) \|\|
	434	__put_user(0, dirent->d_name + namlen))
	435	goto efault;
	436	return 0;
	437	efault:
	438	buf->result = -EFAULT;
	439	return -EFAULT;
	440	}
	441
	442	COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
	443	struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
	444	{
	445	int error;
	446	struct fd f = fdget_pos(fd);
	447	struct compat_readdir_callback buf = {
	448	.ctx.actor = compat_fillonedir,
	449	.dirent = dirent
	450	};
	451
	452	if (!f.file)
	453	return -EBADF;
	454
	455	error = iterate_dir(f.file, &buf.ctx);
	456	if (buf.result)
	457	error = buf.result;
	458
	459	fdput_pos(f);
	460	return error;
	461	}
	462
	463	struct compat_linux_dirent {
	464	compat_ulong_t d_ino;
	465	compat_ulong_t d_off;
	466	unsigned short d_reclen;
	467	char d_name[1];
	468	};
	469
	470	struct compat_getdents_callback {
	471	struct dir_context ctx;
	472	struct compat_linux_dirent __user *current_dir;
	473	struct compat_linux_dirent __user *previous;
	474	int count;
	475	int error;
	476	};
	477
	478	static int compat_filldir(struct dir_context ctx, const char name, int namlen,
	479	loff_t offset, u64 ino, unsigned int d_type)
	480	{
	481	struct compat_linux_dirent __user * dirent;
	482	struct compat_getdents_callback *buf =
	483	container_of(ctx, struct compat_getdents_callback, ctx);
	484	compat_ulong_t d_ino;
	485	int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
	486	namlen + 2, sizeof(compat_long_t));
	487
	488	buf->error = -EINVAL; /* only used if we fail.. */
	489	if (reclen > buf->count)
	490	return -EINVAL;
491	d_ino = ino;
492	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
493	buf->error = -EOVERFLOW;
494	return -EOVERFLOW;
495	}
496	dirent = buf->previous;
497	if (dirent) {
498	if (signal_pending(current))
499	return -EINTR;
500	if (__put_user(offset, &dirent->d_off))
501	goto efault;
502	}
503	dirent = buf->current_dir;
504	if (__put_user(d_ino, &dirent->d_ino))
505	goto efault;
506	if (__put_user(reclen, &dirent->d_reclen))
507	goto efault;
508	if (copy_to_user(dirent->d_name, name, namlen))
509	goto efault;
510	if (__put_user(0, dirent->d_name + namlen))
511	goto efault;
512	if (__put_user(d_type, (char __user *) dirent + reclen - 1))
513	goto efault;
514	buf->previous = dirent;
515	dirent = (void __user *)dirent + reclen;
516	buf->current_dir = dirent;
517	buf->count -= reclen;
518	return 0;
519	efault:
520	buf->error = -EFAULT;
521	return -EFAULT;
522	}
523
524	COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
525	struct compat_linux_dirent __user *, dirent, unsigned int, count)
526	{
527	struct fd f;
528	struct compat_linux_dirent __user * lastdirent;
529	struct compat_getdents_callback buf = {
530	.ctx.actor = compat_filldir,
531	.current_dir = dirent,
532	.count = count
533	};
534	int error;
535
96d4f267	536	if (!access_ok(dirent, count))
0460b2a2 AV	537	return -EFAULT;
	538
	539	f = fdget_pos(fd);
	540	if (!f.file)
	541	return -EBADF;
	542
	543	error = iterate_dir(f.file, &buf.ctx);
	544	if (error >= 0)
	545	error = buf.error;
	546	lastdirent = buf.previous;
	547	if (lastdirent) {
	548	if (put_user(buf.ctx.pos, &lastdirent->d_off))
	549	error = -EFAULT;
	550	else
	551	error = count - buf.count;
	552	}
	553	fdput_pos(f);
	554	return error;
	555	}
	556	#endif