leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

compat_ioctl: reimplement SG_IO handling

Browse Source 
There are two code locations that implement the SG_IO ioctl: the old
sg.c driver, and the generic scsi_ioctl helper that is in turn used by
multiple drivers.

To eradicate the old compat_ioctl conversion handler for the SG_IO
command, I implement a readable pair of put_sg_io_hdr() /get_sg_io_hdr()
helper functions that can be used for both compat and native mode,
and then I call this from both drivers.

For the iovec handling, there is already a compat_import_iovec() function
that can simply be called in place of import_iovec().

To avoid having to pass the compat/native state through multiple
indirections, I mark the SG_IO command itself as compatible in
fs/compat_ioctl.c and use in_compat_syscall() to figure out where
we are called from.

As a side-effect of this, the sg.c driver now also accepts the 32-bit
sg_io_hdr format in compat mode using the read/write interface, not
just ioctl. This should improve compatiblity with old 32-bit binaries,
but it would break if any application intentionally passes the 64-bit
data structure in compat mode here.

Steffen Maier helped debug an issue in an earlier version of this patch.

Cc: Steffen Maier <maier@linux.ibm.com>
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>
This commit is contained in:
Arnd Bergmann
2019-03-14 17:45:18 +01:00
parent b6dfb2477f
commit 98aaaec4a1
5 changed files with 143 additions and 159 deletions
Download Patch File Download Diff File Expand all files Collapse all files

132
block/scsi_ioctl.c
View File

@@ -2,6 +2,7 @@
/*
* Copyright (C) 2001 Jens Axboe <axboe@suse.de>
*/
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
@@ -327,7 +328,14 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
struct iov_iter i;
struct iovec *iov = NULL;
ret = import_iovec(rq_data_dir(rq),
#ifdef CONFIG_COMPAT
if (in_compat_syscall())
ret = compat_import_iovec(rq_data_dir(rq),
hdr->dxferp, hdr->iovec_count,
0, &iov, &i);
else
#endif
ret = import_iovec(rq_data_dir(rq),
hdr->dxferp, hdr->iovec_count,
0, &iov, &i);
if (ret < 0)
@@ -542,6 +550,122 @@ static inline int blk_send_start_stop(struct request_queue *q,
return __blk_send_generic(q, bd_disk, GPCMD_START_STOP_UNIT, data);
}
#ifdef CONFIG_COMPAT
struct compat_sg_io_hdr {
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 */
};
#endif
int put_sg_io_hdr(const struct sg_io_hdr *hdr, void __user *argp)
{
#ifdef CONFIG_COMPAT
if (in_compat_syscall()) {
struct compat_sg_io_hdr hdr32 = {
.interface_id = hdr->interface_id,
.dxfer_direction = hdr->dxfer_direction,
.cmd_len = hdr->cmd_len,
.mx_sb_len = hdr->mx_sb_len,
.iovec_count = hdr->iovec_count,
.dxfer_len = hdr->dxfer_len,
.dxferp = (uintptr_t)hdr->dxferp,
.cmdp = (uintptr_t)hdr->cmdp,
.sbp = (uintptr_t)hdr->sbp,
.timeout = hdr->timeout,
.flags = hdr->flags,
.pack_id = hdr->pack_id,
.usr_ptr = (uintptr_t)hdr->usr_ptr,
.status = hdr->status,
.masked_status = hdr->masked_status,
.msg_status = hdr->msg_status,
.sb_len_wr = hdr->sb_len_wr,
.host_status = hdr->host_status,
.driver_status = hdr->driver_status,
.resid = hdr->resid,
.duration = hdr->duration,
.info = hdr->info,
};
if (copy_to_user(argp, &hdr32, sizeof(hdr32)))
return -EFAULT;
return 0;
}
#endif
if (copy_to_user(argp, hdr, sizeof(*hdr)))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(put_sg_io_hdr);
int get_sg_io_hdr(struct sg_io_hdr *hdr, const void __user *argp)
{
#ifdef CONFIG_COMPAT
struct compat_sg_io_hdr hdr32;
if (in_compat_syscall()) {
if (copy_from_user(&hdr32, argp, sizeof(hdr32)))
return -EFAULT;
*hdr = (struct sg_io_hdr) {
.interface_id = hdr32.interface_id,
.dxfer_direction = hdr32.dxfer_direction,
.cmd_len = hdr32.cmd_len,
.mx_sb_len = hdr32.mx_sb_len,
.iovec_count = hdr32.iovec_count,
.dxfer_len = hdr32.dxfer_len,
.dxferp = compat_ptr(hdr32.dxferp),
.cmdp = compat_ptr(hdr32.cmdp),
.sbp = compat_ptr(hdr32.sbp),
.timeout = hdr32.timeout,
.flags = hdr32.flags,
.pack_id = hdr32.pack_id,
.usr_ptr = compat_ptr(hdr32.usr_ptr),
.status = hdr32.status,
.masked_status = hdr32.masked_status,
.msg_status = hdr32.msg_status,
.sb_len_wr = hdr32.sb_len_wr,
.host_status = hdr32.host_status,
.driver_status = hdr32.driver_status,
.resid = hdr32.resid,
.duration = hdr32.duration,
.info = hdr32.info,
};
return 0;
}
#endif
if (copy_from_user(hdr, argp, sizeof(*hdr)))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(get_sg_io_hdr);
int scsi_cmd_ioctl(struct request_queue *q, struct gendisk *bd_disk, fmode_t mode,
unsigned int cmd, void __user *arg)
{
@@ -581,14 +705,14 @@ int scsi_cmd_ioctl(struct request_queue *q, struct gendisk *bd_disk, fmode_t mod
case SG_IO: {
struct sg_io_hdr hdr;
err = -EFAULT;
if (copy_from_user(&hdr, arg, sizeof(hdr)))
err = get_sg_io_hdr(&hdr, arg);
if (err)
break;
err = sg_io(q, bd_disk, &hdr, mode);
if (err == -EFAULT)
break;
if (copy_to_user(arg, &hdr, sizeof(hdr)))
if (put_sg_io_hdr(&hdr, arg))
err = -EFAULT;
break;
}