fs/compat_ioctl.c

// SPDX-License-Identifier: GPL-2.0
/*
 * ioctl32.c: Conversion between 32bit and 64bit native ioctls.
 *
 * Copyright (C) 1997-2000  Jakub Jelinek  (jakub@redhat.com)
 * Copyright (C) 1998  Eddie C. Dost  (ecd@skynet.be)
 * Copyright (C) 2001,2002  Andi Kleen, SuSE Labs 
 * Copyright (C) 2003       Pavel Machek (pavel@ucw.cz)
 *
 * These routines maintain argument size conversion between 32bit and 64bit
 * ioctls.
 */

#include <linux/types.h>
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/capability.h>
#include <linux/compiler.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/ioctl.h>
#include <linux/if.h>
#include <linux/raid/md_u.h>
#include <linux/falloc.h>
#include <linux/file.h>
#include <linux/ppp-ioctl.h>
#include <linux/if_pppox.h>
#include <linux/tty.h>
#include <linux/vt_kern.h>
#include <linux/blkdev.h>
#include <linux/serial.h>
#include <linux/ctype.h>
#include <linux/syscalls.h>
#include <linux/gfp.h>
#include <linux/cec.h>

#include "internal.h"

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_sock.h>
#include <net/bluetooth/rfcomm.h>

#ifdef CONFIG_BLOCK
#include <linux/cdrom.h>
#include <linux/fd.h>
#include <scsi/scsi.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/sg.h>
#endif

#include <linux/uaccess.h>
#include <linux/watchdog.h>

#include <linux/hiddev.h>


#include <linux/sort.h>

#define convert_in_user(srcptr, dstptr)			\
({							\
	typeof(*srcptr) val;				\
							\
	get_user(val, srcptr) || put_user(val, dstptr);	\
})

/* helper function to avoid trivial compat_ioctl() implementations */
long generic_compat_ioctl_ptrarg(struct file *file, unsigned int cmd, unsigned long arg)
{
	if (!file->f_op->unlocked_ioctl)
		return -ENOIOCTLCMD;

	return file->f_op->unlocked_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
EXPORT_SYMBOL_GPL(generic_compat_ioctl_ptrarg);

static int do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	int err;

	err = security_file_ioctl(file, cmd, arg);
	if (err)
		return err;

	return vfs_ioctl(file, cmd, arg);
}

#ifdef CONFIG_BLOCK
typedef struct sg_io_hdr32 {
	compat_int_t interface_id;	/* [i] 'S' for SCSI generic (required) */
	compat_int_t dxfer_direction;	/* [i] data transfer direction  */
	unsigned char cmd_len;		/* [i] SCSI command length ( <= 16 bytes) */
	unsigned char mx_sb_len;		/* [i] max length to write to sbp */
	unsigned short iovec_count;	/* [i] 0 implies no scatter gather */
	compat_uint_t dxfer_len;		/* [i] byte count of data transfer */
	compat_uint_t dxferp;		/* [i], [*io] points to data transfer memory
					      or scatter gather list */
	compat_uptr_t cmdp;		/* [i], [*i] points to command to perform */
	compat_uptr_t sbp;		/* [i], [*o] points to sense_buffer memory */
	compat_uint_t timeout;		/* [i] MAX_UINT->no timeout (unit: millisec) */
	compat_uint_t flags;		/* [i] 0 -> default, see SG_FLAG... */
	compat_int_t pack_id;		/* [i->o] unused internally (normally) */
	compat_uptr_t usr_ptr;		/* [i->o] unused internally */
	unsigned char status;		/* [o] scsi status */
	unsigned char masked_status;	/* [o] shifted, masked scsi status */
	unsigned char msg_status;		/* [o] messaging level data (optional) */
	unsigned char sb_len_wr;		/* [o] byte count actually written to sbp */
	unsigned short host_status;	/* [o] errors from host adapter */
	unsigned short driver_status;	/* [o] errors from software driver */
	compat_int_t resid;		/* [o] dxfer_len - actual_transferred */
	compat_uint_t duration;		/* [o] time taken by cmd (unit: millisec) */
	compat_uint_t info;		/* [o] auxiliary information */
} sg_io_hdr32_t;  /* 64 bytes long (on sparc32) */

typedef struct sg_iovec32 {
	compat_uint_t iov_base;
	compat_uint_t iov_len;
} sg_iovec32_t;

static int sg_build_iovec(sg_io_hdr_t __user *sgio, void __user *dxferp, u16 iovec_count)
{
	sg_iovec_t __user *iov = (sg_iovec_t __user *) (sgio + 1);
	sg_iovec32_t __user *iov32 = dxferp;
	int i;

	for (i = 0; i < iovec_count; i++) {
		u32 base, len;

		if (get_user(base, &iov32[i].iov_base) ||
		    get_user(len, &iov32[i].iov_len) ||
		    put_user(compat_ptr(base), &iov[i].iov_base) ||
		    put_user(len, &iov[i].iov_len))
			return -EFAULT;
	}

	if (put_user(iov, &sgio->dxferp))
		return -EFAULT;
	return 0;
}

static int sg_ioctl_trans(struct file *file, unsigned int cmd,
			sg_io_hdr32_t __user *sgio32)
{
	sg_io_hdr_t __user *sgio;
	u16 iovec_count;
	u32 data;
	void __user *dxferp;
	int err;
	int interface_id;

	if (get_user(interface_id, &sgio32->interface_id))
		return -EFAULT;
	if (interface_id != 'S')
		return do_ioctl(file, cmd, (unsigned long)sgio32);

	if (get_user(iovec_count, &sgio32->iovec_count))
		return -EFAULT;

	{
		void __user *top = compat_alloc_user_space(0);
		void __user *new = compat_alloc_user_space(sizeof(sg_io_hdr_t) +
				       (iovec_count * sizeof(sg_iovec_t)));
		if (new > top)
			return -EINVAL;

		sgio = new;
	}

	/* Ok, now construct.  */
	if (copy_in_user(&sgio->interface_id, &sgio32->interface_id,
			 (2 * sizeof(int)) +
			 (2 * sizeof(unsigned char)) +
			 (1 * sizeof(unsigned short)) +
			 (1 * sizeof(unsigned int))))
		return -EFAULT;

	if (get_user(data, &sgio32->dxferp))
		return -EFAULT;
	dxferp = compat_ptr(data);
	if (iovec_count) {
		if (sg_build_iovec(sgio, dxferp, iovec_count))
			return -EFAULT;
	} else {
		if (put_user(dxferp, &sgio->dxferp))
			return -EFAULT;
	}

	{
		unsigned char __user *cmdp;
		unsigned char __user *sbp;

		if (get_user(data, &sgio32->cmdp))
			return -EFAULT;
		cmdp = compat_ptr(data);

		if (get_user(data, &sgio32->sbp))
			return -EFAULT;
		sbp = compat_ptr(data);

		if (put_user(cmdp, &sgio->cmdp) ||
		    put_user(sbp, &sgio->sbp))
			return -EFAULT;
	}

	if (copy_in_user(&sgio->timeout, &sgio32->timeout,
			 3 * sizeof(int)))
		return -EFAULT;

	if (get_user(data, &sgio32->usr_ptr))
		return -EFAULT;
	if (put_user(compat_ptr(data), &sgio->usr_ptr))
		return -EFAULT;

	err = do_ioctl(file, cmd, (unsigned long) sgio);

	if (err >= 0) {
		void __user *datap;

		if (copy_in_user(&sgio32->pack_id, &sgio->pack_id,
				 sizeof(int)) ||
		    get_user(datap, &sgio->usr_ptr) ||
		    put_user((u32)(unsigned long)datap,
			     &sgio32->usr_ptr) ||
		    copy_in_user(&sgio32->status, &sgio->status,
				 (4 * sizeof(unsigned char)) +
				 (2 * sizeof(unsigned short)) +
				 (3 * sizeof(int))))
			err = -EFAULT;
	}

	return err;
}

struct compat_sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
	char req_state;
	char orphan;
	char sg_io_owned;
	char problem;
	int pack_id;
	compat_uptr_t usr_ptr;
	unsigned int duration;
	int unused;
};

static int sg_grt_trans(struct file *file,
		unsigned int cmd, struct compat_sg_req_info __user *o)
{
	int err, i;
	sg_req_info_t __user *r;
	r = compat_alloc_user_space(sizeof(sg_req_info_t)*SG_MAX_QUEUE);
	err = do_ioctl(file, cmd, (unsigned long)r);
	if (err < 0)
		return err;
	for (i = 0; i < SG_MAX_QUEUE; i++) {
		void __user *ptr;
		int d;

		if (copy_in_user(o + i, r + i, offsetof(sg_req_info_t, usr_ptr)) ||
		    get_user(ptr, &r[i].usr_ptr) ||
		    get_user(d, &r[i].duration) ||
		    put_user((u32)(unsigned long)(ptr), &o[i].usr_ptr) ||
		    put_user(d, &o[i].duration))
			return -EFAULT;
	}
	return err;
}
#endif /* CONFIG_BLOCK */

struct sock_fprog32 {
	unsigned short	len;
	compat_caddr_t	filter;
};

#define PPPIOCSPASS32	_IOW('t', 71, struct sock_fprog32)
#define PPPIOCSACTIVE32	_IOW('t', 70, struct sock_fprog32)

static int ppp_sock_fprog_ioctl_trans(struct file *file,
		unsigned int cmd, struct sock_fprog32 __user *u_fprog32)
{
	struct sock_fprog __user *u_fprog64 = compat_alloc_user_space(sizeof(struct sock_fprog));
	void __user *fptr64;
	u32 fptr32;
	u16 flen;

	if (get_user(flen, &u_fprog32->len) ||
	    get_user(fptr32, &u_fprog32->filter))
		return -EFAULT;

	fptr64 = compat_ptr(fptr32);

	if (put_user(flen, &u_fprog64->len) ||
	    put_user(fptr64, &u_fprog64->filter))
		return -EFAULT;

	if (cmd == PPPIOCSPASS32)
		cmd = PPPIOCSPASS;
	else
		cmd = PPPIOCSACTIVE;

	return do_ioctl(file, cmd, (unsigned long) u_fprog64);
}

struct ppp_option_data32 {
	compat_caddr_t	ptr;
	u32			length;
	compat_int_t		transmit;
};
#define PPPIOCSCOMPRESS32	_IOW('t', 77, struct ppp_option_data32)

struct ppp_idle32 {
	compat_time_t xmit_idle;
	compat_time_t recv_idle;
};
#define PPPIOCGIDLE32		_IOR('t', 63, struct ppp_idle32)

static int ppp_gidle(struct file *file, unsigned int cmd,
		struct ppp_idle32 __user *idle32)
{
	struct ppp_idle __user *idle;
	__kernel_time_t xmit, recv;
	int err;

	idle = compat_alloc_user_space(sizeof(*idle));

	err = do_ioctl(file, PPPIOCGIDLE, (unsigned long) idle);

	if (!err) {
		if (get_user(xmit, &idle->xmit_idle) ||
		    get_user(recv, &idle->recv_idle) ||
		    put_user(xmit, &idle32->xmit_idle) ||
		    put_user(recv, &idle32->recv_idle))
			err = -EFAULT;
	}
	return err;
}

static int ppp_scompress(struct file *file, unsigned int cmd,
	struct ppp_option_data32 __user *odata32)
{
	struct ppp_option_data __user *odata;
	__u32 data;
	void __user *datap;

	odata = compat_alloc_user_space(sizeof(*odata));

	if (get_user(data, &odata32->ptr))
		return -EFAULT;

	datap = compat_ptr(data);
	if (put_user(datap, &odata->ptr))
		return -EFAULT;

	if (copy_in_user(&odata->length, &odata32->length,
			 sizeof(__u32) + sizeof(int)))
		return -EFAULT;

	return do_ioctl(file, PPPIOCSCOMPRESS, (unsigned long) odata);
}

#endif /* CONFIG_BLOCK */

/* Bluetooth ioctls */
#define HCIUARTSETPROTO		_IOW('U', 200, int)
#define HCIUARTGETPROTO		_IOR('U', 201, int)
#define HCIUARTGETDEVICE	_IOR('U', 202, int)
#define HCIUARTSETFLAGS		_IOW('U', 203, int)
#define HCIUARTGETFLAGS		_IOR('U', 204, int)

/* on ia32 l_start is on a 32-bit boundary */
#if defined(CONFIG_IA64) || defined(CONFIG_X86_64)
struct space_resv_32 {
	__s16		l_type;
	__s16		l_whence;
	__s64		l_start	__attribute__((packed));
			/* len == 0 means until end of file */
	__s64		l_len __attribute__((packed));
	__s32		l_sysid;
	__u32		l_pid;
	__s32		l_pad[4];	/* reserve area */
};

#define FS_IOC_RESVSP_32		_IOW ('X', 40, struct space_resv_32)
#define FS_IOC_RESVSP64_32	_IOW ('X', 42, struct space_resv_32)

/* just account for different alignment */
static int compat_ioctl_preallocate(struct file *file,
			struct space_resv_32    __user *p32)
{
	struct space_resv	__user *p = compat_alloc_user_space(sizeof(*p));

	if (copy_in_user(&p->l_type,	&p32->l_type,	sizeof(s16)) ||
	    copy_in_user(&p->l_whence,	&p32->l_whence, sizeof(s16)) ||
	    copy_in_user(&p->l_start,	&p32->l_start,	sizeof(s64)) ||
	    copy_in_user(&p->l_len,	&p32->l_len,	sizeof(s64)) ||
	    copy_in_user(&p->l_sysid,	&p32->l_sysid,	sizeof(s32)) ||
	    copy_in_user(&p->l_pid,	&p32->l_pid,	sizeof(u32)) ||
	    copy_in_user(&p->l_pad,	&p32->l_pad,	4*sizeof(u32)))
		return -EFAULT;

	return ioctl_preallocate(file, p);
}
#endif

/*
 * simple reversible transform to make our table more evenly
 * distributed after sorting.
 */
#define XFORM(i) (((i) ^ ((i) << 27) ^ ((i) << 17)) & 0xffffffff)

#define COMPATIBLE_IOCTL(cmd) XFORM((u32)cmd),
static unsigned int ioctl_pointer[] = {
/* Little t */
COMPATIBLE_IOCTL(TIOCOUTQ)
/* Little f */
COMPATIBLE_IOCTL(FIOCLEX)
COMPATIBLE_IOCTL(FIONCLEX)
COMPATIBLE_IOCTL(FIOASYNC)
COMPATIBLE_IOCTL(FIONBIO)
COMPATIBLE_IOCTL(FIONREAD)  /* This is also TIOCINQ */
COMPATIBLE_IOCTL(FS_IOC_FIEMAP)
/* 0x00 */
COMPATIBLE_IOCTL(FIBMAP)
COMPATIBLE_IOCTL(FIGETBSZ)
/* 'X' - originally XFS but some now in the VFS */
COMPATIBLE_IOCTL(FIFREEZE)
COMPATIBLE_IOCTL(FITHAW)
COMPATIBLE_IOCTL(FITRIM)
#ifdef CONFIG_BLOCK
/* Big S */
COMPATIBLE_IOCTL(SCSI_IOCTL_GET_IDLUN)
COMPATIBLE_IOCTL(SCSI_IOCTL_DOORLOCK)
COMPATIBLE_IOCTL(SCSI_IOCTL_DOORUNLOCK)
COMPATIBLE_IOCTL(SCSI_IOCTL_TEST_UNIT_READY)
COMPATIBLE_IOCTL(SCSI_IOCTL_GET_BUS_NUMBER)
COMPATIBLE_IOCTL(SCSI_IOCTL_SEND_COMMAND)
COMPATIBLE_IOCTL(SCSI_IOCTL_PROBE_HOST)
COMPATIBLE_IOCTL(SCSI_IOCTL_GET_PCI)
#endif
/*
 * These two are only for the sbus rtc driver, but
 * hwclock tries them on every rtc device first when
 * running on sparc.  On other architectures the entries
 * are useless but harmless.
 */
COMPATIBLE_IOCTL(_IOR('p', 20, int[7])) /* RTCGET */
COMPATIBLE_IOCTL(_IOW('p', 21, int[7])) /* RTCSET */
/* Socket level stuff */
COMPATIBLE_IOCTL(FIOQSIZE)
#ifdef CONFIG_BLOCK
/* SG stuff */
COMPATIBLE_IOCTL(SG_SET_TIMEOUT)
COMPATIBLE_IOCTL(SG_GET_TIMEOUT)
COMPATIBLE_IOCTL(SG_EMULATED_HOST)
COMPATIBLE_IOCTL(SG_GET_TRANSFORM)
COMPATIBLE_IOCTL(SG_SET_RESERVED_SIZE)
COMPATIBLE_IOCTL(SG_GET_RESERVED_SIZE)
COMPATIBLE_IOCTL(SG_GET_SCSI_ID)
COMPATIBLE_IOCTL(SG_SET_FORCE_LOW_DMA)
COMPATIBLE_IOCTL(SG_GET_LOW_DMA)
COMPATIBLE_IOCTL(SG_SET_FORCE_PACK_ID)
COMPATIBLE_IOCTL(SG_GET_PACK_ID)
COMPATIBLE_IOCTL(SG_GET_NUM_WAITING)
COMPATIBLE_IOCTL(SG_SET_DEBUG)
COMPATIBLE_IOCTL(SG_GET_SG_TABLESIZE)
COMPATIBLE_IOCTL(SG_GET_COMMAND_Q)
COMPATIBLE_IOCTL(SG_SET_COMMAND_Q)
COMPATIBLE_IOCTL(SG_GET_VERSION_NUM)
COMPATIBLE_IOCTL(SG_NEXT_CMD_LEN)
COMPATIBLE_IOCTL(SG_SCSI_RESET)
COMPATIBLE_IOCTL(SG_GET_REQUEST_TABLE)
COMPATIBLE_IOCTL(SG_SET_KEEP_ORPHAN)
COMPATIBLE_IOCTL(SG_GET_KEEP_ORPHAN)
#endif
/* PPP stuff */
COMPATIBLE_IOCTL(PPPIOCGFLAGS)
COMPATIBLE_IOCTL(PPPIOCSFLAGS)
COMPATIBLE_IOCTL(PPPIOCGASYNCMAP)
COMPATIBLE_IOCTL(PPPIOCSASYNCMAP)
COMPATIBLE_IOCTL(PPPIOCGUNIT)
COMPATIBLE_IOCTL(PPPIOCGRASYNCMAP)
COMPATIBLE_IOCTL(PPPIOCSRASYNCMAP)
COMPATIBLE_IOCTL(PPPIOCGMRU)
COMPATIBLE_IOCTL(PPPIOCSMRU)
COMPATIBLE_IOCTL(PPPIOCSMAXCID)
COMPATIBLE_IOCTL(PPPIOCGXASYNCMAP)
COMPATIBLE_IOCTL(PPPIOCSXASYNCMAP)
COMPATIBLE_IOCTL(PPPIOCXFERUNIT)
/* PPPIOCSCOMPRESS is translated */
COMPATIBLE_IOCTL(PPPIOCGNPMODE)
COMPATIBLE_IOCTL(PPPIOCSNPMODE)
COMPATIBLE_IOCTL(PPPIOCGDEBUG)
COMPATIBLE_IOCTL(PPPIOCSDEBUG)
/* PPPIOCSPASS is translated */
/* PPPIOCSACTIVE is translated */
/* PPPIOCGIDLE is translated */
COMPATIBLE_IOCTL(PPPIOCNEWUNIT)
COMPATIBLE_IOCTL(PPPIOCATTACH)
COMPATIBLE_IOCTL(PPPIOCDETACH)
COMPATIBLE_IOCTL(PPPIOCSMRRU)
COMPATIBLE_IOCTL(PPPIOCCONNECT)
COMPATIBLE_IOCTL(PPPIOCDISCONN)
COMPATIBLE_IOCTL(PPPIOCATTCHAN)
COMPATIBLE_IOCTL(PPPIOCGCHAN)
COMPATIBLE_IOCTL(PPPIOCGL2TPSTATS)
/* PPPOX */
COMPATIBLE_IOCTL(PPPOEIOCSFWD)
COMPATIBLE_IOCTL(PPPOEIOCDFWD)
/* Watchdog */
COMPATIBLE_IOCTL(WDIOC_GETSUPPORT)
COMPATIBLE_IOCTL(WDIOC_GETSTATUS)
COMPATIBLE_IOCTL(WDIOC_GETBOOTSTATUS)
COMPATIBLE_IOCTL(WDIOC_GETTEMP)
COMPATIBLE_IOCTL(WDIOC_SETOPTIONS)
COMPATIBLE_IOCTL(WDIOC_KEEPALIVE)
COMPATIBLE_IOCTL(WDIOC_SETTIMEOUT)
COMPATIBLE_IOCTL(WDIOC_GETTIMEOUT)
COMPATIBLE_IOCTL(WDIOC_SETPRETIMEOUT)
COMPATIBLE_IOCTL(WDIOC_GETPRETIMEOUT)
/* Bluetooth */
COMPATIBLE_IOCTL(HCIDEVUP)
COMPATIBLE_IOCTL(HCIDEVDOWN)
COMPATIBLE_IOCTL(HCIDEVRESET)
COMPATIBLE_IOCTL(HCIDEVRESTAT)
COMPATIBLE_IOCTL(HCIGETDEVLIST)
COMPATIBLE_IOCTL(HCIGETDEVINFO)
COMPATIBLE_IOCTL(HCIGETCONNLIST)
COMPATIBLE_IOCTL(HCIGETCONNINFO)
COMPATIBLE_IOCTL(HCIGETAUTHINFO)
COMPATIBLE_IOCTL(HCISETRAW)
COMPATIBLE_IOCTL(HCISETSCAN)
COMPATIBLE_IOCTL(HCISETAUTH)
COMPATIBLE_IOCTL(HCISETENCRYPT)
COMPATIBLE_IOCTL(HCISETPTYPE)
COMPATIBLE_IOCTL(HCISETLINKPOL)
COMPATIBLE_IOCTL(HCISETLINKMODE)
COMPATIBLE_IOCTL(HCISETACLMTU)
COMPATIBLE_IOCTL(HCISETSCOMTU)
COMPATIBLE_IOCTL(HCIBLOCKADDR)
COMPATIBLE_IOCTL(HCIUNBLOCKADDR)
COMPATIBLE_IOCTL(HCIINQUIRY)
COMPATIBLE_IOCTL(HCIUARTSETPROTO)
COMPATIBLE_IOCTL(HCIUARTGETPROTO)
COMPATIBLE_IOCTL(HCIUARTGETDEVICE)
COMPATIBLE_IOCTL(HCIUARTSETFLAGS)
COMPATIBLE_IOCTL(HCIUARTGETFLAGS)
COMPATIBLE_IOCTL(RFCOMMCREATEDEV)
COMPATIBLE_IOCTL(RFCOMMRELEASEDEV)
COMPATIBLE_IOCTL(RFCOMMGETDEVLIST)
COMPATIBLE_IOCTL(RFCOMMGETDEVINFO)
COMPATIBLE_IOCTL(RFCOMMSTEALDLC)
/* Misc. */
COMPATIBLE_IOCTL(0x41545900)		/* ATYIO_CLKR */
COMPATIBLE_IOCTL(0x41545901)		/* ATYIO_CLKW */
};

/*
 * Convert common ioctl arguments based on their command number
 *
 * Please do not add any code in here. Instead, implement
 * a compat_ioctl operation in the place that handleѕ the
 * ioctl for the native case.
 */
static long do_ioctl_trans(unsigned int cmd,
		 unsigned long arg, struct file *file)
{
	switch (cmd) {
	case PPPIOCGIDLE32:
		return ppp_gidle(file, cmd, argp);
	case PPPIOCSCOMPRESS32:
		return ppp_scompress(file, cmd, argp);
	case PPPIOCSPASS32:
	case PPPIOCSACTIVE32:
		return ppp_sock_fprog_ioctl_trans(file, cmd, argp);
#ifdef CONFIG_BLOCK
	case SG_IO:
		return sg_ioctl_trans(file, cmd, argp);
	case SG_GET_REQUEST_TABLE:
		return sg_grt_trans(file, cmd, argp);
#endif
	}

	return -ENOIOCTLCMD;
}

static int compat_ioctl_check_table(unsigned int xcmd)
{
	int i;
	const int max = ARRAY_SIZE(ioctl_pointer) - 1;

	BUILD_BUG_ON(max >= (1 << 16));

	/* guess initial offset into table, assuming a
	   normalized distribution */
	i = ((xcmd >> 16) * max) >> 16;

	/* do linear search up first, until greater or equal */
	while (ioctl_pointer[i] < xcmd && i < max)
		i++;

	/* then do linear search down */
	while (ioctl_pointer[i] > xcmd && i > 0)
		i--;

	return ioctl_pointer[i] == xcmd;
}

COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,
		       compat_ulong_t, arg32)
{
	unsigned long arg = arg32;
	struct fd f = fdget(fd);
	int error = -EBADF;
	if (!f.file)
		goto out;

	/* RED-PEN how should LSM module know it's handling 32bit? */
	error = security_file_ioctl(f.file, cmd, arg);
	if (error)
		goto out_fput;

	/*
	 * To allow the compat_ioctl handlers to be self contained
	 * we need to check the common ioctls here first.
	 * Just handle them with the standard handlers below.
	 */
	switch (cmd) {
	case FIOCLEX:
	case FIONCLEX:
	case FIONBIO:
	case FIOASYNC:
	case FIOQSIZE:
		break;

#if defined(CONFIG_IA64) || defined(CONFIG_X86_64)
	case FS_IOC_RESVSP_32:
	case FS_IOC_RESVSP64_32:
		error = compat_ioctl_preallocate(f.file, compat_ptr(arg));
		goto out_fput;
#else
	case FS_IOC_RESVSP:
	case FS_IOC_RESVSP64:
		error = ioctl_preallocate(f.file, compat_ptr(arg));
		goto out_fput;
#endif

	case FICLONE:
	case FICLONERANGE:
	case FIDEDUPERANGE:
	case FS_IOC_FIEMAP:
		goto do_ioctl;

	case FIBMAP:
	case FIGETBSZ:
	case FIONREAD:
		if (S_ISREG(file_inode(f.file)->i_mode))
			break;
		/*FALL THROUGH*/

	default:
		if (f.file->f_op->compat_ioctl) {
			error = f.file->f_op->compat_ioctl(f.file, cmd, arg);
			if (error != -ENOIOCTLCMD)
				goto out_fput;
		}

		if (!f.file->f_op->unlocked_ioctl)
			goto do_ioctl;
		break;
	}

	if (compat_ioctl_check_table(XFORM(cmd)))
		goto found_handler;

	error = do_ioctl_trans(cmd, arg, f.file);
	if (error == -ENOIOCTLCMD)
		error = -ENOTTY;

	goto out_fput;

 found_handler:
	arg = (unsigned long)compat_ptr(arg);
 do_ioctl:
	error = do_vfs_ioctl(f.file, fd, cmd, arg);
 out_fput:
	fdput(f);
 out:
	return error;
}

static int __init init_sys32_ioctl_cmp(const void *p, const void *q)
{
	unsigned int a, b;
	a = *(unsigned int *)p;
	b = *(unsigned int *)q;
	if (a > b)
		return 1;
	if (a < b)
		return -1;
	return 0;
}

static int __init init_sys32_ioctl(void)
{
	sort(ioctl_pointer, ARRAY_SIZE(ioctl_pointer), sizeof(*ioctl_pointer),
		init_sys32_ioctl_cmp, NULL);
	return 0;
}
__initcall(init_sys32_ioctl);