scsi: scsi_ioctl: Validate command size

Need to make sure the command size is valid before copying the command from
user space.

Link: https://lore.kernel.org/r/[email protected]
Cc: Bart Van Assche <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: James E.J. Bottomley <[email protected]>
Cc: Martin K. Petersen <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]> # 5.15, 5.14, 5.10
Signed-off-by: Tadeusz Struk <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: tstruk

drivers/scsi/scsi_ioctl.c

@@ -347,6 +347,8 @@ static int scsi_fill_sghdr_rq(struct scsi_device *sdev, struct request *rq,
 {
 	struct scsi_request *req = scsi_req(rq);
 
+	if (hdr->cmd_len < 6)
+		return -EMSGSIZE;
 	if (copy_from_user(req->cmd, hdr->cmdp, hdr->cmd_len))
 		return -EFAULT;
 	if (!scsi_cmd_allowed(req->cmd, mode))