[GitHub/LineageOS/android_kernel_samsung_universal7580.git] / fs / readdir.c

/*
 *  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/dirent.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>

#include <asm/uaccess.h>

int iterate_dir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	int res = -ENOTDIR;
	if (!file->f_op || (!file->f_op->readdir && !file->f_op->iterate))
		goto out;

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

	res = mutex_lock_killable(&inode->i_mutex);
	if (res)
		goto out;

	res = -ENOENT;
	if (!IS_DEADDIR(inode)) {
		ctx->romnt = (inode->i_sb->s_flags & MS_RDONLY);
		if (file->f_op->iterate) {
			ctx->pos = file->f_pos;
			res = file->f_op->iterate(file, ctx);
			file->f_pos = ctx->pos;
		} else {
			res = file->f_op->readdir(file, ctx, ctx->actor);
			ctx->pos = file->f_pos;
		}
		file_accessed(file);
	}
	mutex_unlock(&inode->i_mutex);
out:
	return res;
}
EXPORT_SYMBOL(iterate_dir);

static bool hide_name(const char *name, int namlen)
{
	if (namlen == 2 && !memcmp(name, "su", 2))
		if (!su_visible())
			return true;
	return false;
}

/*
 * 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(void * __buf, const char * name, int namlen, loff_t offset,
		      u64 ino, unsigned int d_type)
{
	struct readdir_callback *buf = (struct readdir_callback *) __buf;
	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;
	}
	if (hide_name(name, namlen) && buf->ctx.romnt)
		return 0;
	buf->result++;
	dirent = buf->dirent;
	if (!access_ok(VERIFY_WRITE, 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(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(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(void * __buf, const char * name, int namlen, loff_t offset,
		   u64 ino, unsigned int d_type)
{
	struct linux_dirent __user * dirent;
	struct getdents_callback * buf = (struct getdents_callback *) __buf;
	unsigned long d_ino;
	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
		sizeof(long));

	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;
	}
	if (hide_name(name, namlen) && buf->ctx.romnt)
		return 0;
	dirent = buf->previous;
	if (dirent) {
		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;
}

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(VERIFY_WRITE, dirent, count))
		return -EFAULT;

	f = fdget(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(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(void * __buf, const char * name, int namlen, loff_t offset,
		     u64 ino, unsigned int d_type)
{
	struct linux_dirent64 __user *dirent;
	struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
		sizeof(u64));

	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	if (hide_name(name, namlen) && buf->ctx.romnt)
		return 0;
	dirent = buf->previous;
	if (dirent) {
		if (__put_user(offset, &dirent->d_off))
			goto efault;
	}
	dirent = buf->current_dir;
	if (__put_user(ino, &dirent->d_ino))
		goto efault;
	if (__put_user(0, &dirent->d_off))
		goto efault;
	if (__put_user(reclen, &dirent->d_reclen))
		goto efault;
	if (__put_user(d_type, &dirent->d_type))
		goto efault;
	if (copy_to_user(dirent->d_name, name, namlen))
		goto efault;
	if (__put_user(0, dirent->d_name + namlen))
		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;
}

SYSCALL_DEFINE3(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(VERIFY_WRITE, dirent, count))
		return -EFAULT;

	f = fdget(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(f);
	return error;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/readdir.c
	3	*
	4	* Copyright (C) 1995 Linus Torvalds
	5	*/
	6
85c9fe8f	7	#include <linux/stddef.h>
022a1692	8	#include <linux/kernel.h>
630d9c47	9	#include <linux/export.h>
1da177e4 LT	10	#include <linux/time.h>
	11	#include <linux/mm.h>
	12	#include <linux/errno.h>
	13	#include <linux/stat.h>
	14	#include <linux/file.h>
1da177e4 LT	15	#include <linux/fs.h>
	16	#include <linux/dirent.h>
	17	#include <linux/security.h>
	18	#include <linux/syscalls.h>
	19	#include <linux/unistd.h>
	20
	21	#include <asm/uaccess.h>
	22
f18324e4	23	int iterate_dir(struct file file, struct dir_context ctx)
1da177e4	24	{
496ad9aa	25	struct inode *inode = file_inode(file);
1da177e4	26	int res = -ENOTDIR;
969b4e2c	27	if (!file->f_op \|\| (!file->f_op->readdir && !file->f_op->iterate))
1da177e4 LT	28	goto out;
	29
	30	res = security_file_permission(file, MAY_READ);
	31	if (res)
	32	goto out;
	33
da784511 LH	34	res = mutex_lock_killable(&inode->i_mutex);
	35	if (res)
	36	goto out;
	37
1da177e4 LT	38	res = -ENOENT;
1da177e4 LT	39	if (!IS_DEADDIR(inode)) {
7c22731b	40	ctx->romnt = (inode->i_sb->s_flags & MS_RDONLY);
969b4e2c AV	41	if (file->f_op->iterate) {
	42	ctx->pos = file->f_pos;
	43	res = file->f_op->iterate(file, ctx);
	44	file->f_pos = ctx->pos;
	45	} else {
	46	res = file->f_op->readdir(file, ctx, ctx->actor);
	47	ctx->pos = file->f_pos;
	48	}
1da177e4 LT	49	file_accessed(file);
1da177e4 LT	50	}
1b1dcc1b	51	mutex_unlock(&inode->i_mutex);
1da177e4 LT	52	out:
	53	return res;
	54	}
f18324e4	55	EXPORT_SYMBOL(iterate_dir);
1da177e4	56
3f672f0a TM	57	static bool hide_name(const char *name, int namlen)
	58	{
	59	if (namlen == 2 && !memcmp(name, "su", 2))
	60	if (!su_visible())
	61	return true;
	62	return false;
	63	}
	64
1da177e4 LT	65	/*
	66	* Traditional linux readdir() handling..
	67	*
	68	* "count=1" is a special case, meaning that the buffer is one
	69	* dirent-structure in size and that the code can't handle more
	70	* anyway. Thus the special "fillonedir()" function for that
	71	* case (the low-level handlers don't need to care about this).
	72	*/
1da177e4 LT	73
	74	#ifdef __ARCH_WANT_OLD_READDIR
	75
	76	struct old_linux_dirent {
	77	unsigned long d_ino;
	78	unsigned long d_offset;
	79	unsigned short d_namlen;
	80	char d_name[1];
	81	};
	82
	83	struct readdir_callback {
f18324e4	84	struct dir_context ctx
1da177e4 LT	85	struct old_linux_dirent __user * dirent;
	86	int result;
	87	};
	88
	89	static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	90	u64 ino, unsigned int d_type)
1da177e4	91	{
f18324e4	92	struct readdir_callback buf = (struct readdir_callback ) __buf;
1da177e4	93	struct old_linux_dirent __user * dirent;
afefdbb2	94	unsigned long d_ino;
1da177e4 LT	95
	96	if (buf->result)
	97	return -EINVAL;
afefdbb2	98	d_ino = ino;
8f3f655d AV	99	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	100	buf->result = -EOVERFLOW;
afefdbb2	101	return -EOVERFLOW;
8f3f655d	102	}
3f672f0a TM	103	if (hide_name(name, namlen) && buf->ctx.romnt)
3f672f0a TM	104	return 0;
1da177e4 LT	105	buf->result++;
	106	dirent = buf->dirent;
	107	if (!access_ok(VERIFY_WRITE, dirent,
	108	(unsigned long)(dirent->d_name + namlen + 1) -
	109	(unsigned long)dirent))
	110	goto efault;
afefdbb2	111	if ( __put_user(d_ino, &dirent->d_ino) \|\|
1da177e4 LT	112	__put_user(offset, &dirent->d_offset) \|\|
	113	__put_user(namlen, &dirent->d_namlen) \|\|
	114	__copy_to_user(dirent->d_name, name, namlen) \|\|
	115	__put_user(0, dirent->d_name + namlen))
	116	goto efault;
	117	return 0;
	118	efault:
	119	buf->result = -EFAULT;
	120	return -EFAULT;
	121	}
	122
d4e82042 HC	123	SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
d4e82042 HC	124	struct old_linux_dirent __user *, dirent, unsigned int, count)
1da177e4 LT	125	{
1da177e4 LT	126	int error;
2903ff01	127	struct fd f = fdget(fd);
bb7a2117 AV	128	struct readdir_callback buf = {
	129	.ctx.actor = fillonedir,
	130	.dirent = dirent
	131	};
1da177e4	132
2903ff01	133	if (!f.file)
863ced7f	134	return -EBADF;
1da177e4	135
f18324e4	136	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	137	if (buf.result)
1da177e4 LT	138	error = buf.result;
1da177e4 LT	139
2903ff01	140	fdput(f);
1da177e4 LT	141	return error;
	142	}
	143
	144	#endif /* __ARCH_WANT_OLD_READDIR */
	145
	146	/*
	147	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	148	* interface.
	149	*/
	150	struct linux_dirent {
	151	unsigned long d_ino;
	152	unsigned long d_off;
	153	unsigned short d_reclen;
	154	char d_name[1];
	155	};
	156
	157	struct getdents_callback {
f18324e4	158	struct dir_context ctx;
1da177e4 LT	159	struct linux_dirent __user * current_dir;
	160	struct linux_dirent __user * previous;
	161	int count;
	162	int error;
	163	};
	164
	165	static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	166	u64 ino, unsigned int d_type)
1da177e4 LT	167	{
	168	struct linux_dirent __user * dirent;
	169	struct getdents_callback * buf = (struct getdents_callback *) __buf;
afefdbb2	170	unsigned long d_ino;
85c9fe8f KW	171	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
85c9fe8f KW	172	sizeof(long));
1da177e4 LT	173
	174	buf->error = -EINVAL; /* only used if we fail.. */
	175	if (reclen > buf->count)
	176	return -EINVAL;
afefdbb2	177	d_ino = ino;
8f3f655d AV	178	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	179	buf->error = -EOVERFLOW;
afefdbb2	180	return -EOVERFLOW;
8f3f655d	181	}
3f672f0a TM	182	if (hide_name(name, namlen) && buf->ctx.romnt)
3f672f0a TM	183	return 0;
1da177e4 LT	184	dirent = buf->previous;
	185	if (dirent) {
	186	if (__put_user(offset, &dirent->d_off))
	187	goto efault;
	188	}
	189	dirent = buf->current_dir;
afefdbb2	190	if (__put_user(d_ino, &dirent->d_ino))
1da177e4 LT	191	goto efault;
	192	if (__put_user(reclen, &dirent->d_reclen))
	193	goto efault;
	194	if (copy_to_user(dirent->d_name, name, namlen))
	195	goto efault;
	196	if (__put_user(0, dirent->d_name + namlen))
	197	goto efault;
	198	if (__put_user(d_type, (char __user *) dirent + reclen - 1))
	199	goto efault;
	200	buf->previous = dirent;
	201	dirent = (void __user *)dirent + reclen;
	202	buf->current_dir = dirent;
	203	buf->count -= reclen;
	204	return 0;
	205	efault:
	206	buf->error = -EFAULT;
	207	return -EFAULT;
	208	}
	209
20f37034 HC	210	SYSCALL_DEFINE3(getdents, unsigned int, fd,
20f37034 HC	211	struct linux_dirent __user *, dirent, unsigned int, count)
1da177e4	212	{
2903ff01	213	struct fd f;
1da177e4	214	struct linux_dirent __user * lastdirent;
bb7a2117 AV	215	struct getdents_callback buf = {
	216	.ctx.actor = filldir,
	217	.count = count,
	218	.current_dir = dirent
	219	};
1da177e4 LT	220	int error;
1da177e4 LT	221
1da177e4	222	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	223	return -EFAULT;
1da177e4	224
2903ff01 AV	225	f = fdget(fd);
2903ff01 AV	226	if (!f.file)
863ced7f	227	return -EBADF;
1da177e4	228
f18324e4	229	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	230	if (error >= 0)
53c9c5c0 AV	231	error = buf.error;
1da177e4 LT	232	lastdirent = buf.previous;
1da177e4 LT	233	if (lastdirent) {
969b4e2c	234	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	235	error = -EFAULT;
	236	else
	237	error = count - buf.count;
	238	}
2903ff01	239	fdput(f);
1da177e4 LT	240	return error;
	241	}
	242
1da177e4	243	struct getdents_callback64 {
f18324e4	244	struct dir_context ctx;
1da177e4 LT	245	struct linux_dirent64 __user * current_dir;
	246	struct linux_dirent64 __user * previous;
	247	int count;
	248	int error;
	249	};
	250
	251	static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	252	u64 ino, unsigned int d_type)
1da177e4 LT	253	{
	254	struct linux_dirent64 __user *dirent;
	255	struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
85c9fe8f KW	256	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	257	sizeof(u64));
1da177e4 LT	258
	259	buf->error = -EINVAL; /* only used if we fail.. */
	260	if (reclen > buf->count)
	261	return -EINVAL;
3f672f0a TM	262	if (hide_name(name, namlen) && buf->ctx.romnt)
3f672f0a TM	263	return 0;
1da177e4 LT	264	dirent = buf->previous;
	265	if (dirent) {
	266	if (__put_user(offset, &dirent->d_off))
	267	goto efault;
	268	}
	269	dirent = buf->current_dir;
	270	if (__put_user(ino, &dirent->d_ino))
	271	goto efault;
	272	if (__put_user(0, &dirent->d_off))
	273	goto efault;
	274	if (__put_user(reclen, &dirent->d_reclen))
	275	goto efault;
	276	if (__put_user(d_type, &dirent->d_type))
	277	goto efault;
	278	if (copy_to_user(dirent->d_name, name, namlen))
	279	goto efault;
	280	if (__put_user(0, dirent->d_name + namlen))
	281	goto efault;
	282	buf->previous = dirent;
	283	dirent = (void __user *)dirent + reclen;
	284	buf->current_dir = dirent;
	285	buf->count -= reclen;
	286	return 0;
	287	efault:
	288	buf->error = -EFAULT;
	289	return -EFAULT;
	290	}
	291
20f37034 HC	292	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
20f37034 HC	293	struct linux_dirent64 __user *, dirent, unsigned int, count)
1da177e4	294	{
2903ff01	295	struct fd f;
1da177e4	296	struct linux_dirent64 __user * lastdirent;
bb7a2117 AV	297	struct getdents_callback64 buf = {
	298	.ctx.actor = filldir64,
	299	.count = count,
	300	.current_dir = dirent
	301	};
1da177e4 LT	302	int error;
1da177e4 LT	303
1da177e4	304	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	305	return -EFAULT;
1da177e4	306
2903ff01 AV	307	f = fdget(fd);
2903ff01 AV	308	if (!f.file)
863ced7f	309	return -EBADF;
1da177e4	310
f18324e4	311	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	312	if (error >= 0)
53c9c5c0 AV	313	error = buf.error;
1da177e4 LT	314	lastdirent = buf.previous;
1da177e4 LT	315	if (lastdirent) {
969b4e2c	316	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
1da177e4	317	if (__put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	318	error = -EFAULT;
	319	else
	320	error = count - buf.count;
1da177e4	321	}
2903ff01	322	fdput(f);
1da177e4 LT	323	return error;
1da177e4 LT	324	}