[people/ms/linux.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.
 *
 * Note the PATH_MAX check - it's arbitrary but the real
 * kernel limit on a possible path component, not NAME_MAX,
 * which is the technical standard limit.
 */
static int verify_dirent_name(const char *name, int len)
{
	if (len <= 0 || len >= PATH_MAX)
		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;
	buf->result = verify_dirent_name(name, namlen);
	if (buf->result < 0)
		return buf->result;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->result = -EOVERFLOW;
		return -EOVERFLOW;
	}
	buf->result++;
	dirent = buf->dirent;
	if (!user_write_access_begin(dirent,
			(unsigned long)(dirent->d_name + namlen + 1) -
				(unsigned long)dirent))
		goto efault;
	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	unsafe_put_user(offset, &dirent->d_offset, efault_end);
	unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	user_write_access_end();
	return 0;
efault_end:
	user_write_access_end();
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;
	int prev_reclen;
	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, *prev;
	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));
	int prev_reclen;

	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;
	}
	prev_reclen = buf->prev_reclen;
	if (prev_reclen && signal_pending(current))
		return -EINTR;
	dirent = buf->current_dir;
	prev = (void __user *) dirent - prev_reclen;
	if (!user_write_access_begin(prev, reclen + prev_reclen))
		goto efault;

	/* This might be 'dirent->d_off', but if so it will get overwritten */
	unsafe_put_user(offset, &prev->d_off, efault_end);
	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_write_access_end();

	buf->current_dir = (void __user *)dirent + reclen;
	buf->prev_reclen = reclen;
	buf->count -= reclen;
	return 0;
efault_end:
	user_write_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 getdents_callback buf = {
		.ctx.actor = filldir,
		.count = count,
		.current_dir = dirent
	};
	int error;

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

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	if (buf.prev_reclen) {
		struct linux_dirent __user * lastdirent;
		lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;

		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;
	int prev_reclen;
	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, *prev;
	struct getdents_callback64 *buf =
		container_of(ctx, struct getdents_callback64, ctx);
	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
		sizeof(u64));
	int prev_reclen;

	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;
	prev_reclen = buf->prev_reclen;
	if (prev_reclen && signal_pending(current))
		return -EINTR;
	dirent = buf->current_dir;
	prev = (void __user *)dirent - prev_reclen;
	if (!user_write_access_begin(prev, reclen + prev_reclen))
		goto efault;

	/* This might be 'dirent->d_off', but if so it will get overwritten */
	unsafe_put_user(offset, &prev->d_off, efault_end);
	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_write_access_end();

	buf->prev_reclen = reclen;
	buf->current_dir = (void __user *)dirent + reclen;
	buf->count -= reclen;
	return 0;

efault_end:
	user_write_access_end();
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

SYSCALL_DEFINE3(getdents64, unsigned int, fd,
		struct linux_dirent64 __user *, dirent, unsigned int, count)
{
	struct fd f;
	struct getdents_callback64 buf = {
		.ctx.actor = filldir64,
		.count = count,
		.current_dir = dirent
	};
	int error;

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

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	if (buf.prev_reclen) {
		struct linux_dirent64 __user * lastdirent;
		typeof(lastdirent->d_off) d_off = buf.ctx.pos;

		lastdirent = (void __user *) buf.current_dir - buf.prev_reclen;
		if (put_user(d_off, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}
	fdput_pos(f);
	return error;
}

#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;
	buf->result = verify_dirent_name(name, namlen);
	if (buf->result < 0)
		return buf->result;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->result = -EOVERFLOW;
		return -EOVERFLOW;
	}
	buf->result++;
	dirent = buf->dirent;
	if (!user_write_access_begin(dirent,
			(unsigned long)(dirent->d_name + namlen + 1) -
				(unsigned long)dirent))
		goto efault;
	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	unsafe_put_user(offset, &dirent->d_offset, efault_end);
	unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	user_write_access_end();
	return 0;
efault_end:
	user_write_access_end();
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;
	int prev_reclen;
	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, *prev;
	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));
	int prev_reclen;

	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;
	}
	prev_reclen = buf->prev_reclen;
	if (prev_reclen && signal_pending(current))
		return -EINTR;
	dirent = buf->current_dir;
	prev = (void __user *) dirent - prev_reclen;
	if (!user_write_access_begin(prev, reclen + prev_reclen))
		goto efault;

	unsafe_put_user(offset, &prev->d_off, efault_end);
	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_write_access_end();

	buf->prev_reclen = reclen;
	buf->current_dir = (void __user *)dirent + reclen;
	buf->count -= reclen;
	return 0;
efault_end:
	user_write_access_end();
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_getdents_callback buf = {
		.ctx.actor = compat_filldir,
		.current_dir = dirent,
		.count = count
	};
	int error;

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

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	if (buf.prev_reclen) {
		struct compat_linux_dirent __user * lastdirent;
		lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;

		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.
2c6b7bcd LT	105	*
	106	* Note the PATH_MAX check - it's arbitrary but the real
	107	* kernel limit on a possible path component, not NAME_MAX,
	108	* which is the technical standard limit.
8a23eb80 LT	109	*/
	110	static int verify_dirent_name(const char *name, int len)
	111	{
2c6b7bcd	112	if (len <= 0 \|\| len >= PATH_MAX)
8a23eb80	113	return -EIO;
b9959c7a	114	if (memchr(name, '/', len))
8a23eb80 LT	115	return -EIO;
	116	return 0;
	117	}
	118
1da177e4 LT	119	/*
	120	* Traditional linux readdir() handling..
	121	*
	122	* "count=1" is a special case, meaning that the buffer is one
	123	* dirent-structure in size and that the code can't handle more
	124	* anyway. Thus the special "fillonedir()" function for that
	125	* case (the low-level handlers don't need to care about this).
	126	*/
1da177e4 LT	127
	128	#ifdef __ARCH_WANT_OLD_READDIR
	129
	130	struct old_linux_dirent {
	131	unsigned long d_ino;
	132	unsigned long d_offset;
	133	unsigned short d_namlen;
	134	char d_name[1];
	135	};
	136
	137	struct readdir_callback {
5c0ba4e0	138	struct dir_context ctx;
1da177e4 LT	139	struct old_linux_dirent __user * dirent;
	140	int result;
	141	};
	142
ac7576f4 MS	143	static int fillonedir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	144	loff_t offset, u64 ino, unsigned int d_type)
1da177e4	145	{
ac7576f4 MS	146	struct readdir_callback *buf =
ac7576f4 MS	147	container_of(ctx, struct readdir_callback, ctx);
1da177e4	148	struct old_linux_dirent __user * dirent;
afefdbb2	149	unsigned long d_ino;
1da177e4 LT	150
	151	if (buf->result)
	152	return -EINVAL;
0c93ac69 LT	153	buf->result = verify_dirent_name(name, namlen);
	154	if (buf->result < 0)
	155	return buf->result;
afefdbb2	156	d_ino = ino;
8f3f655d AV	157	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	158	buf->result = -EOVERFLOW;
afefdbb2	159	return -EOVERFLOW;
8f3f655d	160	}
1da177e4 LT	161	buf->result++;
1da177e4 LT	162	dirent = buf->dirent;
391b7461	163	if (!user_write_access_begin(dirent,
1da177e4 LT	164	(unsigned long)(dirent->d_name + namlen + 1) -
	165	(unsigned long)dirent))
	166	goto efault;
391b7461 AV	167	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	168	unsafe_put_user(offset, &dirent->d_offset, efault_end);
	169	unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
	170	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	171	user_write_access_end();
1da177e4	172	return 0;
391b7461 AV	173	efault_end:
391b7461 AV	174	user_write_access_end();
1da177e4 LT	175	efault:
	176	buf->result = -EFAULT;
	177	return -EFAULT;
	178	}
	179
d4e82042 HC	180	SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
d4e82042 HC	181	struct old_linux_dirent __user *, dirent, unsigned int, count)
1da177e4 LT	182	{
1da177e4 LT	183	int error;
63b6df14	184	struct fd f = fdget_pos(fd);
ac6614b7 AV	185	struct readdir_callback buf = {
	186	.ctx.actor = fillonedir,
	187	.dirent = dirent
	188	};
1da177e4	189
2903ff01	190	if (!f.file)
863ced7f	191	return -EBADF;
1da177e4	192
5c0ba4e0	193	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	194	if (buf.result)
1da177e4 LT	195	error = buf.result;
1da177e4 LT	196
63b6df14	197	fdput_pos(f);
1da177e4 LT	198	return error;
	199	}
	200
	201	#endif /* __ARCH_WANT_OLD_READDIR */
	202
	203	/*
	204	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	205	* interface.
	206	*/
	207	struct linux_dirent {
	208	unsigned long d_ino;
	209	unsigned long d_off;
	210	unsigned short d_reclen;
	211	char d_name[1];
	212	};
	213
	214	struct getdents_callback {
5c0ba4e0	215	struct dir_context ctx;
1da177e4	216	struct linux_dirent __user * current_dir;
3c2659bd	217	int prev_reclen;
1da177e4 LT	218	int count;
	219	int error;
	220	};
	221
ac7576f4 MS	222	static int filldir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	223	loff_t offset, u64 ino, unsigned int d_type)
1da177e4	224	{
3c2659bd	225	struct linux_dirent __user dirent, prev;
ac7576f4 MS	226	struct getdents_callback *buf =
ac7576f4 MS	227	container_of(ctx, struct getdents_callback, ctx);
afefdbb2	228	unsigned long d_ino;
85c9fe8f KW	229	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
85c9fe8f KW	230	sizeof(long));
3c2659bd	231	int prev_reclen;
1da177e4	232
8a23eb80 LT	233	buf->error = verify_dirent_name(name, namlen);
	234	if (unlikely(buf->error))
	235	return buf->error;
1da177e4 LT	236	buf->error = -EINVAL; /* only used if we fail.. */
	237	if (reclen > buf->count)
	238	return -EINVAL;
afefdbb2	239	d_ino = ino;
8f3f655d AV	240	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	241	buf->error = -EOVERFLOW;
afefdbb2	242	return -EOVERFLOW;
8f3f655d	243	}
3c2659bd LT	244	prev_reclen = buf->prev_reclen;
3c2659bd LT	245	if (prev_reclen && signal_pending(current))
9f79b78e	246	return -EINTR;
9f79b78e	247	dirent = buf->current_dir;
3c2659bd	248	prev = (void __user *) dirent - prev_reclen;
41cd7805	249	if (!user_write_access_begin(prev, reclen + prev_reclen))
3c2659bd LT	250	goto efault;
	251
	252	/* This might be 'dirent->d_off', but if so it will get overwritten */
	253	unsafe_put_user(offset, &prev->d_off, efault_end);
9f79b78e LT	254	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	255	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	256	unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
	257	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
41cd7805	258	user_write_access_end();
9f79b78e	259
3c2659bd LT	260	buf->current_dir = (void __user *)dirent + reclen;
3c2659bd LT	261	buf->prev_reclen = reclen;
1da177e4 LT	262	buf->count -= reclen;
1da177e4 LT	263	return 0;
9f79b78e	264	efault_end:
41cd7805	265	user_write_access_end();
1da177e4 LT	266	efault:
	267	buf->error = -EFAULT;
	268	return -EFAULT;
	269	}
	270
20f37034 HC	271	SYSCALL_DEFINE3(getdents, unsigned int, fd,
20f37034 HC	272	struct linux_dirent __user *, dirent, unsigned int, count)
1da177e4	273	{
2903ff01	274	struct fd f;
ac6614b7 AV	275	struct getdents_callback buf = {
	276	.ctx.actor = filldir,
	277	.count = count,
	278	.current_dir = dirent
	279	};
1da177e4 LT	280	int error;
1da177e4 LT	281
63b6df14	282	f = fdget_pos(fd);
2903ff01	283	if (!f.file)
863ced7f	284	return -EBADF;
1da177e4	285
5c0ba4e0	286	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	287	if (error >= 0)
53c9c5c0 AV	288	error = buf.error;
3c2659bd LT	289	if (buf.prev_reclen) {
	290	struct linux_dirent __user * lastdirent;
	291	lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;
	292
bb6f619b	293	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	294	error = -EFAULT;
	295	else
	296	error = count - buf.count;
	297	}
63b6df14	298	fdput_pos(f);
1da177e4 LT	299	return error;
	300	}
	301
1da177e4	302	struct getdents_callback64 {
5c0ba4e0	303	struct dir_context ctx;
1da177e4	304	struct linux_dirent64 __user * current_dir;
3c2659bd	305	int prev_reclen;
1da177e4 LT	306	int count;
	307	int error;
	308	};
	309
ac7576f4 MS	310	static int filldir64(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	311	loff_t offset, u64 ino, unsigned int d_type)
1da177e4	312	{
3c2659bd	313	struct linux_dirent64 __user dirent, prev;
ac7576f4 MS	314	struct getdents_callback64 *buf =
ac7576f4 MS	315	container_of(ctx, struct getdents_callback64, ctx);
85c9fe8f KW	316	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	317	sizeof(u64));
3c2659bd	318	int prev_reclen;
1da177e4	319
8a23eb80 LT	320	buf->error = verify_dirent_name(name, namlen);
	321	if (unlikely(buf->error))
	322	return buf->error;
1da177e4 LT	323	buf->error = -EINVAL; /* only used if we fail.. */
	324	if (reclen > buf->count)
	325	return -EINVAL;
3c2659bd LT	326	prev_reclen = buf->prev_reclen;
3c2659bd LT	327	if (prev_reclen && signal_pending(current))
9f79b78e	328	return -EINTR;
9f79b78e	329	dirent = buf->current_dir;
3c2659bd	330	prev = (void __user *)dirent - prev_reclen;
41cd7805	331	if (!user_write_access_begin(prev, reclen + prev_reclen))
3c2659bd LT	332	goto efault;
	333
	334	/* This might be 'dirent->d_off', but if so it will get overwritten */
	335	unsafe_put_user(offset, &prev->d_off, efault_end);
9f79b78e LT	336	unsafe_put_user(ino, &dirent->d_ino, efault_end);
	337	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	338	unsafe_put_user(d_type, &dirent->d_type, efault_end);
	339	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
41cd7805	340	user_write_access_end();
9f79b78e	341
3c2659bd LT	342	buf->prev_reclen = reclen;
3c2659bd LT	343	buf->current_dir = (void __user *)dirent + reclen;
1da177e4 LT	344	buf->count -= reclen;
1da177e4 LT	345	return 0;
3c2659bd	346
9f79b78e	347	efault_end:
41cd7805	348	user_write_access_end();
1da177e4 LT	349	efault:
	350	buf->error = -EFAULT;
	351	return -EFAULT;
	352	}
	353
fb2da16c CH	354	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
fb2da16c CH	355	struct linux_dirent64 __user *, dirent, unsigned int, count)
1da177e4	356	{
2903ff01	357	struct fd f;
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
63b6df14	365	f = fdget_pos(fd);
2903ff01	366	if (!f.file)
863ced7f	367	return -EBADF;
1da177e4	368
5c0ba4e0	369	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	370	if (error >= 0)
53c9c5c0 AV	371	error = buf.error;
3c2659bd LT	372	if (buf.prev_reclen) {
3c2659bd LT	373	struct linux_dirent64 __user * lastdirent;
bb6f619b	374	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
3c2659bd LT	375
3c2659bd LT	376	lastdirent = (void __user *) buf.current_dir - buf.prev_reclen;
5fb15141	377	if (put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	378	error = -EFAULT;
	379	else
	380	error = count - buf.count;
1da177e4	381	}
63b6df14	382	fdput_pos(f);
1da177e4 LT	383	return error;
1da177e4 LT	384	}
0460b2a2 AV	385
	386	#ifdef CONFIG_COMPAT
	387	struct compat_old_linux_dirent {
	388	compat_ulong_t d_ino;
	389	compat_ulong_t d_offset;
	390	unsigned short d_namlen;
	391	char d_name[1];
	392	};
	393
	394	struct compat_readdir_callback {
	395	struct dir_context ctx;
	396	struct compat_old_linux_dirent __user *dirent;
	397	int result;
	398	};
	399
	400	static int compat_fillonedir(struct dir_context ctx, const char name,
	401	int namlen, loff_t offset, u64 ino,
	402	unsigned int d_type)
	403	{
	404	struct compat_readdir_callback *buf =
	405	container_of(ctx, struct compat_readdir_callback, ctx);
	406	struct compat_old_linux_dirent __user *dirent;
	407	compat_ulong_t d_ino;
	408
	409	if (buf->result)
	410	return -EINVAL;
0c93ac69 LT	411	buf->result = verify_dirent_name(name, namlen);
	412	if (buf->result < 0)
	413	return buf->result;
0460b2a2 AV	414	d_ino = ino;
	415	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
	416	buf->result = -EOVERFLOW;
	417	return -EOVERFLOW;
	418	}
	419	buf->result++;
	420	dirent = buf->dirent;
391b7461	421	if (!user_write_access_begin(dirent,
0460b2a2 AV	422	(unsigned long)(dirent->d_name + namlen + 1) -
	423	(unsigned long)dirent))
	424	goto efault;
391b7461 AV	425	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	426	unsafe_put_user(offset, &dirent->d_offset, efault_end);
	427	unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
	428	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	429	user_write_access_end();
0460b2a2	430	return 0;
391b7461 AV	431	efault_end:
391b7461 AV	432	user_write_access_end();
0460b2a2 AV	433	efault:
	434	buf->result = -EFAULT;
	435	return -EFAULT;
	436	}
	437
	438	COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
	439	struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
	440	{
	441	int error;
	442	struct fd f = fdget_pos(fd);
	443	struct compat_readdir_callback buf = {
	444	.ctx.actor = compat_fillonedir,
	445	.dirent = dirent
	446	};
	447
	448	if (!f.file)
	449	return -EBADF;
	450
	451	error = iterate_dir(f.file, &buf.ctx);
	452	if (buf.result)
	453	error = buf.result;
	454
	455	fdput_pos(f);
	456	return error;
	457	}
	458
	459	struct compat_linux_dirent {
	460	compat_ulong_t d_ino;
	461	compat_ulong_t d_off;
	462	unsigned short d_reclen;
	463	char d_name[1];
	464	};
	465
	466	struct compat_getdents_callback {
	467	struct dir_context ctx;
	468	struct compat_linux_dirent __user *current_dir;
82af599b	469	int prev_reclen;
0460b2a2 AV	470	int count;
	471	int error;
	472	};
	473
	474	static int compat_filldir(struct dir_context ctx, const char name, int namlen,
	475	loff_t offset, u64 ino, unsigned int d_type)
	476	{
82af599b	477	struct compat_linux_dirent __user dirent, prev;
0460b2a2 AV	478	struct compat_getdents_callback *buf =
	479	container_of(ctx, struct compat_getdents_callback, ctx);
	480	compat_ulong_t d_ino;
	481	int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
	482	namlen + 2, sizeof(compat_long_t));
82af599b	483	int prev_reclen;
0460b2a2	484
82af599b AV	485	buf->error = verify_dirent_name(name, namlen);
	486	if (unlikely(buf->error))
	487	return buf->error;
0460b2a2 AV	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	}
82af599b AV	496	prev_reclen = buf->prev_reclen;
	497	if (prev_reclen && signal_pending(current))
	498	return -EINTR;
0460b2a2	499	dirent = buf->current_dir;
82af599b AV	500	prev = (void __user *) dirent - prev_reclen;
82af599b AV	501	if (!user_write_access_begin(prev, reclen + prev_reclen))
0460b2a2	502	goto efault;
82af599b AV	503
	504	unsafe_put_user(offset, &prev->d_off, efault_end);
	505	unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
	506	unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
	507	unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
	508	unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
	509	user_write_access_end();
	510
	511	buf->prev_reclen = reclen;
	512	buf->current_dir = (void __user *)dirent + reclen;
0460b2a2 AV	513	buf->count -= reclen;
0460b2a2 AV	514	return 0;
82af599b AV	515	efault_end:
82af599b AV	516	user_write_access_end();
0460b2a2 AV	517	efault:
	518	buf->error = -EFAULT;
	519	return -EFAULT;
	520	}
	521
	522	COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
	523	struct compat_linux_dirent __user *, dirent, unsigned int, count)
	524	{
	525	struct fd f;
0460b2a2 AV	526	struct compat_getdents_callback buf = {
	527	.ctx.actor = compat_filldir,
	528	.current_dir = dirent,
	529	.count = count
	530	};
	531	int error;
	532
0460b2a2 AV	533	f = fdget_pos(fd);
	534	if (!f.file)
	535	return -EBADF;
	536
	537	error = iterate_dir(f.file, &buf.ctx);
	538	if (error >= 0)
	539	error = buf.error;
82af599b AV	540	if (buf.prev_reclen) {
	541	struct compat_linux_dirent __user * lastdirent;
	542	lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;
	543
0460b2a2 AV	544	if (put_user(buf.ctx.pos, &lastdirent->d_off))
	545	error = -EFAULT;
	546	else
	547	error = count - buf.count;
	548	}
	549	fdput_pos(f);
	550	return error;
	551	}
	552	#endif