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linux-next/fs/compat_ioctl.c
Arnd Bergmann fd6c3d5acc compat_ioctl: move SG_GET_REQUEST_TABLE handling
SG_GET_REQUEST_TABLE is now the last ioctl command that needs a conversion
handler. This is only used in a single file, so the implementation should
be there.

I'm trying to simplify it in the process, to get rid of
the compat_alloc_user_space() and extra copy, by adding a
put_compat_request_table() function instead, which copies the data in
the right format to user space.

Cc: linux-scsi@vger.kernel.org
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-10-23 17:23:47 +02:00

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// 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"
#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>
/*
* 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[] = {
#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
#ifdef CONFIG_BLOCK
/* SG stuff */
COMPATIBLE_IOCTL(SG_IO)
COMPATIBLE_IOCTL(SG_GET_REQUEST_TABLE)
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
};
/*
* 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)
{
return -ENOIOCTLCMD;
}
static int compat_ioctl_check_table(unsigned int xcmd)
{
#ifdef CONFIG_BLOCK
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;
#else
return 0;
#endif
}
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;
switch (cmd) {
/* these are never seen by ->ioctl(), no argument or int argument */
case FIOCLEX:
case FIONCLEX:
case FIFREEZE:
case FITHAW:
case FICLONE:
goto do_ioctl;
/* these are never seen by ->ioctl(), pointer argument */
case FIONBIO:
case FIOASYNC:
case FIOQSIZE:
case FS_IOC_FIEMAP:
case FIGETBSZ:
case FICLONERANGE:
case FIDEDUPERANGE:
goto found_handler;
/*
* The next group is the stuff handled inside file_ioctl().
* For regular files these never reach ->ioctl(); for
* devices, sockets, etc. they do and one (FIONREAD) is
* even accepted in some cases. In all those cases
* argument has the same type, so we can handle these
* here, shunting them towards do_vfs_ioctl().
* ->compat_ioctl() will never see any of those.
*/
/* pointer argument, never actually handled by ->ioctl() */
case FIBMAP:
goto found_handler;
/* handled by some ->ioctl(); always a pointer to int */
case FIONREAD:
goto found_handler;
/* these two get messy on amd64 due to alignment differences */
#if 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:
goto found_handler;
#endif
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);