diff --git a/block/parallels.c b/block/parallels.c
index 2121e4320455..5d1c0af35471 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -49,7 +49,7 @@ typedef struct BDRVParallelsState {
     CoMutex lock;
 
     uint32_t *catalog_bitmap;
-    int catalog_size;
+    unsigned int catalog_size;
 
     int tracks;
 } BDRVParallelsState;
@@ -94,6 +94,11 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
     s->tracks = le32_to_cpu(ph.tracks);
 
     s->catalog_size = le32_to_cpu(ph.catalog_entries);
+    if (s->catalog_size > INT_MAX / 4) {
+        error_setg(errp, "Catalog too large");
+        ret = -EFBIG;
+        goto fail;
+    }
     s->catalog_bitmap = g_malloc(s->catalog_size * 4);
 
     ret = bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4);
diff --git a/tests/qemu-iotests/076 b/tests/qemu-iotests/076
new file mode 100755
index 000000000000..6028ac5db0f6
--- /dev/null
+++ b/tests/qemu-iotests/076
@@ -0,0 +1,69 @@
+#!/bin/bash
+#
+# parallels format input validation tests
+#
+# Copyright (C) 2013 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()
+{
+	_cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt parallels
+_supported_proto generic
+_supported_os Linux
+
+catalog_entries_offset=$((0x20))
+nb_sectors_offset=$((0x24))
+
+echo
+echo "== Read from a valid (enough) image =="
+_use_sample_img fake.parallels.bz2
+{ $QEMU_IO -c "read -P 0x11 0 64k" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo
+echo "== Negative catalog size =="
+_use_sample_img fake.parallels.bz2
+poke_file "$TEST_IMG" "$catalog_entries_offset" "\xff\xff\xff\xff"
+{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo
+echo "== Overflow in catalog allocation =="
+_use_sample_img fake.parallels.bz2
+poke_file "$TEST_IMG" "$nb_sectors_offset" "\xff\xff\xff\xff"
+poke_file "$TEST_IMG" "$catalog_entries_offset" "\x01\x00\x00\x40"
+{ $QEMU_IO -c "read 64M 64M" $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/076.out b/tests/qemu-iotests/076.out
new file mode 100644
index 000000000000..12af42ac1cbe
--- /dev/null
+++ b/tests/qemu-iotests/076.out
@@ -0,0 +1,14 @@
+QA output created by 076
+
+== Read from a valid (enough) image ==
+read 65536/65536 bytes at offset 0
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Negative catalog size ==
+qemu-io: can't open device TEST_DIR/fake.parallels: Catalog too large
+no file open, try 'help open'
+
+== Overflow in catalog allocation ==
+qemu-io: can't open device TEST_DIR/fake.parallels: Catalog too large
+no file open, try 'help open'
+*** done
diff --git a/tests/qemu-iotests/common b/tests/qemu-iotests/common
index 35abbfcfcbc8..f8c1b56a50a8 100644
--- a/tests/qemu-iotests/common
+++ b/tests/qemu-iotests/common
@@ -131,6 +131,7 @@ check options
     -bochs              test bochs
     -cow                test cow
     -cloop              test cloop
+    -parallels          test parallels
     -qcow               test qcow
     -qcow2              test qcow2
     -qed                test qed
@@ -181,6 +182,12 @@ testlist options
             xpand=false
             ;;
 
+        -parallels)
+            IMGFMT=parallels
+            IMGFMT_GENERIC=false
+            xpand=false
+            ;;
+
         -qcow)
             IMGFMT=qcow
             xpand=false
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index d0b762c0b409..7e0e9a859aa0 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -78,6 +78,7 @@
 070 rw auto
 073 rw auto
 075 rw auto
+076 auto
 078 rw auto
 080 rw auto
 088 rw auto
diff --git a/tests/qemu-iotests/sample_images/fake.parallels.bz2 b/tests/qemu-iotests/sample_images/fake.parallels.bz2
new file mode 100644
index 000000000000..ffb5f13bac31
Binary files /dev/null and b/tests/qemu-iotests/sample_images/fake.parallels.bz2 differ