diff --git a/Makefile.am b/Makefile.am
index 6bf31c6..f63c45d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -267,6 +267,7 @@ bin_iscsi_test_cu_SOURCES = test-tool/iscsi-test-cu.c \
 	test-tool/test_reserve6_target_cold_reset.c \
 	test-tool/test_reserve6_lun_reset.c \
 	test-tool/test_sanitize_simple.c \
+	test-tool/test_sanitize_overwrite.c \
 	test-tool/test_startstopunit_simple.c \
 	test-tool/test_startstopunit_pwrcnd.c \
 	test-tool/test_startstopunit_noloej.c \
diff --git a/test-tool/iscsi-support.c b/test-tool/iscsi-support.c
index 200710b..3a56e9d 100644
--- a/test-tool/iscsi-support.c
+++ b/test-tool/iscsi-support.c
@@ -1350,6 +1350,54 @@ int sanitize(struct iscsi_context *iscsi, int lun, int immed, int ause, int sa,
 	return 0;
 }
 
+int sanitize_invalidfieldincdb(struct iscsi_context *iscsi, int lun, int immed, int ause, int sa, int param_len, struct iscsi_data *data)
+{
+	struct scsi_task *task;
+
+	logging(LOG_VERBOSE, "Send SANITIZE (Expecting INVALID_FIELD_IN_CDB) "
+		"IMMED:%d AUSE:%d SA:%d "
+		"PARAM_LEN:%d",
+		immed, ause, sa, param_len);
+
+	task = iscsi_sanitize_sync(iscsi, lun, immed, ause, sa, param_len,
+				   data);
+	if (task == NULL) {
+		logging(LOG_NORMAL,
+			"[FAILED] Failed to send SANITIZE command: %s",
+			iscsi_get_error(iscsi));
+		return -1;
+	}
+	if (task->status        == SCSI_STATUS_CHECK_CONDITION
+	    && task->sense.key  == SCSI_SENSE_ILLEGAL_REQUEST
+	    && task->sense.ascq == SCSI_SENSE_ASCQ_INVALID_OPERATION_CODE) {
+		logging(LOG_NORMAL, "[SKIPPED] SANITIZE is not "
+			"implemented on target");
+		scsi_free_scsi_task(task);
+		return -2;
+	}
+	if (task->status == SCSI_STATUS_GOOD) {
+		logging(LOG_NORMAL, "[FAILED] SANITIZE successful but should "
+			"have failed with ILLEGAL_REQUEST/INVALID_FIELD_IN_CDB");
+		scsi_free_scsi_task(task);
+		return -1;
+	}
+	if (task->status        != SCSI_STATUS_CHECK_CONDITION
+		|| task->sense.key  != SCSI_SENSE_ILLEGAL_REQUEST
+		|| task->sense.ascq != SCSI_SENSE_ASCQ_INVALID_FIELD_IN_CDB) {
+		logging(LOG_NORMAL, "[FAILED] SANITIZE failed with wrong "
+			"sense. Should have failed with ILLEGAL_REQUEST/"
+			"INVALID_FIELD_IN_CDB. Sense:%s\n",
+			iscsi_get_error(iscsi));
+		scsi_free_scsi_task(task);
+		return -1;
+	}
+
+	scsi_free_scsi_task(task);
+	logging(LOG_VERBOSE, "[OK] SANITIZE returned ILLEGAL_REQUEST/"
+		"INVALID_FIELD_IB_CDB.");
+	return 0;
+}
+
 int startstopunit(struct iscsi_context *iscsi, int lun, int immed, int pcm, int pc, int no_flush, int loej, int start)
 {
 	struct scsi_task *task;
diff --git a/test-tool/iscsi-support.h b/test-tool/iscsi-support.h
index 0b31d5b..9e6d398 100644
--- a/test-tool/iscsi-support.h
+++ b/test-tool/iscsi-support.h
@@ -261,6 +261,7 @@ int release6(struct iscsi_context *iscsi, int lun);
 int reserve6(struct iscsi_context *iscsi, int lun);
 int reserve6_conflict(struct iscsi_context *iscsi, int lun);
 int sanitize(struct iscsi_context *iscsi, int lun, int immed, int ause, int sa, int param_len, struct iscsi_data *data);
+int sanitize_invalidfieldincdb(struct iscsi_context *iscsi, int lun, int immed, int ause, int sa, int param_len, struct iscsi_data *data);
 int startstopunit(struct iscsi_context *iscsi, int lun, int immed, int pcm, int pc, int no_flush, int loej, int start);
 int startstopunit_preventremoval(struct iscsi_context *iscsi, int lun, int immed, int pcm, int pc, int no_flush, int loej, int start);
 int synchronizecache10(struct iscsi_context *iscsi, int lun, uint32_t lba, int num_blocks, int sync_nv, int immed);
diff --git a/test-tool/iscsi-test-cu.c b/test-tool/iscsi-test-cu.c
index 4a1bb0e..d8482e3 100644
--- a/test-tool/iscsi-test-cu.c
+++ b/test-tool/iscsi-test-cu.c
@@ -223,6 +223,7 @@ static CU_TestInfo tests_readonly[] = {
 
 static CU_TestInfo tests_sanitize[] = {
 	{ (char *)"Sanitize", test_sanitize_simple },
+	{ (char *)"Overwrite", test_sanitize_overwrite },
 	CU_TEST_INFO_NULL
 };
 
diff --git a/test-tool/iscsi-test-cu.h b/test-tool/iscsi-test-cu.h
index b19c209..a0376cd 100644
--- a/test-tool/iscsi-test-cu.h
+++ b/test-tool/iscsi-test-cu.h
@@ -152,6 +152,7 @@ void test_reserve6_target_warm_reset(void);
 void test_reserve6_lun_reset(void);
 
 void test_sanitize_simple(void);
+void test_sanitize_overwrite(void);
 
 void test_startstopunit_simple(void);
 void test_startstopunit_pwrcnd(void);
diff --git a/test-tool/test_sanitize_overwrite.c b/test-tool/test_sanitize_overwrite.c
new file mode 100644
index 0000000..064396f
--- /dev/null
+++ b/test-tool/test_sanitize_overwrite.c
@@ -0,0 +1,84 @@
+/* 
+   Copyright (C) 2013 Ronnie Sahlberg <ronniesahlberg@gmail.com>
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <alloca.h>
+
+#include <CUnit/CUnit.h>
+
+#include "iscsi.h"
+#include "scsi-lowlevel.h"
+#include "iscsi-test-cu.h"
+
+void
+test_sanitize_overwrite(void)
+{ 
+	int ret;
+	struct iscsi_data data;
+
+	logging(LOG_VERBOSE, LOG_BLANK_LINE);
+	logging(LOG_VERBOSE, "Test SANITIZE OVERWRITE");
+
+	CHECK_FOR_SANITIZE;
+
+
+	logging(LOG_VERBOSE, "Parameter list length <= 4 is an error");
+	logging(LOG_VERBOSE, "Test that parameter list length == 0 fails");
+		ret = sanitize_invalidfieldincdb(iscsic, tgt_lun,
+		       0, 0, SCSI_SANITIZE_OVERWRITE, 0, NULL);
+	if (ret == -2) {
+		logging(LOG_NORMAL, "[SKIPPED] SANITIZE is not implemented.");
+		CU_PASS("SANITIZE is not implemented.");
+		return;
+	}	
+	CU_ASSERT_EQUAL(ret, 0);
+
+
+	logging(LOG_VERBOSE, "Test that parameter list length == 4 fails");
+	data.size = 4;
+	data.data = alloca(data.size);
+	memset(data.data, 0, data.size);
+		ret = sanitize_invalidfieldincdb(iscsic, tgt_lun,
+		       0, 0, SCSI_SANITIZE_OVERWRITE, data.size, &data);
+	CU_ASSERT_EQUAL(ret, 0);
+
+
+	logging(LOG_VERBOSE, "Parameter list length >= blocksize + 5 is an "
+		"error");
+	logging(LOG_VERBOSE, "Test that parameter list length == blocksize + 8 "
+		"fails");
+	data.size = block_size + 8;
+	data.data = alloca(data.size);
+	memset(data.data, 0, data.size);
+		ret = sanitize_invalidfieldincdb(iscsic, tgt_lun,
+		       0, 0, SCSI_SANITIZE_OVERWRITE, data.size, &data);
+	CU_ASSERT_EQUAL(ret, 0);
+
+
+	logging(LOG_VERBOSE, "Test SANITIZE OVERWRITE of full block of 0xaa");
+	data.size = block_size + 4;
+	data.data[0] = 0x01;
+	data.data[1] = 0x00;
+	data.data[2] = block_size >> 8;
+	data.data[3] = block_size & 0xff;
+	memset(&data.data[4], 0xaa, block_size);
+	ret = sanitize(iscsic, tgt_lun,
+		       0, 0, SCSI_SANITIZE_OVERWRITE, data.size, &data);
+	CU_ASSERT_EQUAL(ret, 0);
+}