From 6a1c90b6d82c2b12d50fd07c6dae8fd1714e6a21 Mon Sep 17 00:00:00 2001
From: krcroft <krcroft@users.noreply.github.com>
Date: Thu, 16 Jan 2020 14:43:03 -0800
Subject: [PATCH] Fix NULL issues in OPL code

The 'ptr' pointer in the 'ptr += sizeof (FM_OPL)' expression could be nullptr. In such case,
resulting value will be senseless and it should not be used.
---
 src/hardware/mame/fmopl.cpp  | 14 +++++++-------
 src/hardware/mame/ymf262.cpp |  8 ++++++++
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/hardware/mame/fmopl.cpp b/src/hardware/mame/fmopl.cpp
index 90b88345..6f5b3dc5 100644
--- a/src/hardware/mame/fmopl.cpp
+++ b/src/hardware/mame/fmopl.cpp
@@ -1958,23 +1958,23 @@ static void OPL_clock_changed(FM_OPL *OPL, uint32_t clock, uint32_t rate)
 /* 'rate'  is sampling rate  */
 static FM_OPL *OPLCreate(device_t *device, uint32_t clock, uint32_t rate, int type)
 {
-	char *ptr;
-	FM_OPL *OPL;
-	int state_size;
-
 	if (FM_OPL::LockTable(device) == -1) return 0;
 
 	/* calculate OPL state size */
-	state_size  = sizeof(FM_OPL);
+	int state_size  = sizeof(FM_OPL);
 
 #if BUILD_Y8950
 	if (type&OPL_TYPE_ADPCM) state_size+= sizeof(YM_DELTAT);
 #endif
 
 	/* allocate memory block */
-	ptr = (char *)auto_alloc_array_clear(device->machine(), uint8_t, state_size);
+	char *ptr = (char *)auto_alloc_array_clear(device->machine(), uint8_t, state_size);
+	if (!ptr) {
+		device->logerror("Could not allocate memory during device creation");
+		return 0;
+	}
 
-	OPL  = (FM_OPL *)ptr;
+	FM_OPL *OPL = (FM_OPL *)ptr;
 
 	ptr += sizeof(FM_OPL);
 
diff --git a/src/hardware/mame/ymf262.cpp b/src/hardware/mame/ymf262.cpp
index 98056c5d..fd2e940a 100644
--- a/src/hardware/mame/ymf262.cpp
+++ b/src/hardware/mame/ymf262.cpp
@@ -2353,12 +2353,20 @@ static void OPL3ResetChip(OPL3 *chip)
 /* 'rate'  is sampling rate  */
 static OPL3 *OPL3Create(device_t *device, int clock, int rate, int type)
 {
+	// Guard
+	if (device == nullptr) {
+		return 0;
+	}
 	OPL3 *chip;
 
 	if (OPL3_LockTable(device) == -1) return 0;
 
 	/* allocate memory block */
 	chip = auto_alloc_clear(device->machine(), OPL3 );
+	if (chip == nullptr) {
+		device->logerror("Could not allocate memory for OPL3 chip");
+		return 0;
+	}
 
 	chip->device = device;
 	chip->type  = type;