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Commit a5efa51a authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by Greg Kroah-Hartman
Browse files

scsi: sg: only check for dxfer_len greater than 256M 



commit f930c7043663188429cd9b254e9d761edfc101ce upstream.

Don't make any assumptions on the sg_io_hdr_t::dxfer_direction or the
sg_io_hdr_t::dxferp in order to determine if it is a valid request. The
only way we can check for bad requests is by checking if the length
exceeds 256M.

Signed-off-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Fixes: 28676d869bbb (scsi: sg: check for valid direction before starting the request)
Reported-by: default avatarJason L Tibbitts III <tibbs@math.uh.edu>
Tested-by: default avatarJason L Tibbitts III <tibbs@math.uh.edu>
Suggested-by: default avatarDoug Gilbert <dgilbert@interlog.com>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 99c2db0e

drivers/scsi/sg.c

+2 −30
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ static int sg_version_num = 30536; /* 2 digits for each component */ 
#include <linux/mutex.h>

#include <linux/atomic.h>

#include <linux/ratelimit.h>

#include <linux/sizes.h>



#include "scsi.h"

#include <scsi/scsi_dbg.h>
@@ -762,35 +763,6 @@ sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf, 
	return count;

}



static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)

{

	switch (hp->dxfer_direction) {

	case SG_DXFER_NONE:

		if (hp->dxferp || hp->dxfer_len > 0)

			return false;

		return true;

	case SG_DXFER_FROM_DEV:

		/*

		 * for SG_DXFER_FROM_DEV we always set dxfer_len to > 0. dxferp

		 * can either be NULL or != NULL so there's no point in checking

		 * it either. So just return true.

		 */

		return true;

	case SG_DXFER_TO_DEV:

	case SG_DXFER_TO_FROM_DEV:

		if (!hp->dxferp || hp->dxfer_len == 0)

			return false;

		return true;

	case SG_DXFER_UNKNOWN:

		if ((!hp->dxferp && hp->dxfer_len) ||

		    (hp->dxferp && hp->dxfer_len == 0))

			return false;

		return true;

	default:

		return false;

	}

}



static int

sg_common_write(Sg_fd * sfp, Sg_request * srp,

		unsigned char *cmnd, int timeout, int blocking)
@@ -811,7 +783,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp, 
			"sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",

			(int) cmnd[0], (int) hp->cmd_len));



	if (!sg_is_valid_dxfer(hp))

	if (hp->dxfer_len >= SZ_256M)

		return -EINVAL;



	k = sg_start_req(srp, cmnd);