From cb8bf9f8f6d24d40e0b6eb64b687b9033f6cbdcb Mon Sep 17 00:00:00 2001
From: ripsaw8080 <ripsaw8080@users.sourceforge.net>
Date: Sat, 2 Jun 2018 18:21:21 +0000
Subject: [PATCH] Return an error for generic block device request on unmounted
 floppy drives. Fixes bug #481.

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@4112
---
 src/dos/dos_ioctl.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/dos/dos_ioctl.cpp b/src/dos/dos_ioctl.cpp
index a8cc9fa0..1357bd72 100644
--- a/src/dos/dos_ioctl.cpp
+++ b/src/dos/dos_ioctl.cpp
@@ -152,6 +152,10 @@ bool DOS_IOCTL(void) {
 		return true;
 	case 0x0D:		/* Generic block device request */
 		{
+			if (drive < 2 && !Drives[drive]) {
+				DOS_SetError(DOSERR_ACCESS_DENIED);
+				return false;
+			}
 			if (Drives[drive]->isRemovable()) {
 				DOS_SetError(DOSERR_FUNCTION_NUMBER_INVALID);
 				return false;