Patch "scsi: sg: only check for dxfer_len greater than 256M" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     scsi-sg-only-check-for-dxfer_len-greater-than-256m.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let [off-list ref] know about it.

From f930c7043663188429cd9b254e9d761edfc101ce Mon Sep 17 00:00:00 2001

From: Johannes Thumshirn <redacted>
Date: Thu, 27 Jul 2017 09:11:26 +0200
Subject: scsi: sg: only check for dxfer_len greater than 256M

From: Johannes Thumshirn <redacted>

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: Johannes Thumshirn <redacted>
Fixes: 28676d869bbb (scsi: sg: check for valid direction before starting the request)
Reported-by: Jason L Tibbitts III <redacted>
Tested-by: Jason L Tibbitts III <redacted>
Suggested-by: Doug Gilbert <dgilbert@interlog.com>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: <redacted>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/scsi/sg.c |   31 +------------------------------
 1 file changed, 1 insertion(+), 30 deletions(-)

--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c

@@ -751,35 +751,6 @@ sg_new_write(Sg_fd *sfp, struct file *fi
 	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)

@@ -800,7 +771,7 @@ sg_common_write(Sg_fd * sfp, Sg_request
 			"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);

Patches currently in stable-queue which might be from jthumshirn@suse.de are

queue-4.9/scsi-sg-fix-static-checker-warning-in-sg_is_valid_dxfer.patch
queue-4.9/scsi-sg-only-check-for-dxfer_len-greater-than-256m.patch
queue-4.9/scsi-sg-check-for-valid-direction-before-starting-the-request.patch
queue-4.9/scsi-sg-close-race-condition-in-sg_remove_sfp_usercontext.patch
queue-4.9/scsi-sg-fix-sg_dxfer_from_dev-transfers.patch
queue-4.9/scsi-core-scsi_get_device_flags_keyed-always-return-device-flags.patch