diff --git a/block/qcow.c b/block/qcow.c
index 3684794..e60df23 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -128,11 +128,17 @@
         goto fail;
     }
 
-    if (header.size <= 1 || header.cluster_bits < 9) {
-        error_setg(errp, "invalid value in qcow header");
+    if (header.size <= 1) {
+        error_setg(errp, "Image size is too small (must be at least 2 bytes)");
         ret = -EINVAL;
         goto fail;
     }
+    if (header.cluster_bits < 9 || header.cluster_bits > 16) {
+        error_setg(errp, "Cluster size must be between 512 and 64k");
+        ret = -EINVAL;
+        goto fail;
+    }
+
     if (header.crypt_method > QCOW_CRYPT_AES) {
         error_setg(errp, "invalid encryption method in qcow header");
         ret = -EINVAL;
diff --git a/tests/qemu-iotests/092 b/tests/qemu-iotests/092
new file mode 100755
index 0000000..d060e6f
--- /dev/null
+++ b/tests/qemu-iotests/092
@@ -0,0 +1,63 @@
+#!/bin/bash
+#
+# qcow1 format input validation tests
+#
+# Copyright (C) 2014 Red Hat, Inc.
+#
+# 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/>.
+#
+
+# creator
+owner=kwolf@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+
+_cleanup()
+{
+    rm -f $TEST_IMG.snap
+    _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow
+_supported_proto generic
+_supported_os Linux
+
+offset_cluster_bits=32
+
+echo
+echo "== Invalid cluster size =="
+_make_test_img 64M
+poke_file "$TEST_IMG" "$offset_cluster_bits" "\xff"
+{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
+poke_file "$TEST_IMG" "$offset_cluster_bits" "\x1f"
+{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
+poke_file "$TEST_IMG" "$offset_cluster_bits" "\x08"
+{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
+poke_file "$TEST_IMG" "$offset_cluster_bits" "\x11"
+{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/092.out b/tests/qemu-iotests/092.out
new file mode 100644
index 0000000..8bf8158
--- /dev/null
+++ b/tests/qemu-iotests/092.out
@@ -0,0 +1,13 @@
+QA output created by 092
+
+== Invalid cluster size ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 
+qemu-io: can't open device TEST_DIR/t.qcow: Cluster size must be between 512 and 64k
+no file open, try 'help open'
+qemu-io: can't open device TEST_DIR/t.qcow: Cluster size must be between 512 and 64k
+no file open, try 'help open'
+qemu-io: can't open device TEST_DIR/t.qcow: Cluster size must be between 512 and 64k
+no file open, try 'help open'
+qemu-io: can't open device TEST_DIR/t.qcow: Cluster size must be between 512 and 64k
+no file open, try 'help open'
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 2988cfd..0f07440 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -98,3 +98,4 @@
 089 rw auto quick
 090 rw auto quick
 091 rw auto
+092 rw auto quick