@@ -448,7 +448,8 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVQcowState *s = bs->opaque;
- int len, i, ret = 0;
+ unsigned int len, i;
+ int ret = 0;
QCowHeader header;
QemuOpts *opts;
Error *local_err = NULL;
@@ -723,8 +724,10 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
/* read the backing file name */
if (header.backing_file_offset != 0) {
len = header.backing_file_size;
- if (len > 1023) {
- len = 1023;
+ if (len > MIN(1023, s->cluster_size - header.backing_file_offset)) {
+ error_setg(errp, "Backing file name too long");
+ ret = -EINVAL;
+ goto fail;
}
ret = bdrv_pread(bs->file, header.backing_file_offset,
bs->backing_file, len);
@@ -45,6 +45,7 @@ _supported_os Linux
header_size=104
offset_backing_file_offset=8
+offset_backing_file_size=16
offset_l1_size=36
offset_l1_table_offset=40
offset_refcount_table_offset=48
@@ -135,6 +136,13 @@ poke_file "$TEST_IMG" "$offset_l1_table_offset" "\x12\x34\x56\x78\x90\xab\xcd\xe
poke_file "$TEST_IMG" "$offset_l1_size" "\x00\x00\x00\x01"
{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
+echo
+echo "== Invalid backing file size =="
+_make_test_img 64M
+poke_file "$TEST_IMG" "$offset_backing_file_offset" "\x00\x00\x00\x00\x00\x00\x10\x00"
+poke_file "$TEST_IMG" "$offset_backing_file_size" "\xff\xff\xff\xff"
+{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir
+
# success, all done
echo "*** done"
rm -f $seq.full
@@ -58,4 +58,9 @@ qemu-io: can't open device TEST_DIR/t.qcow2: Invalid L1 table offset
no file open, try 'help open'
qemu-io: can't open device TEST_DIR/t.qcow2: Invalid L1 table offset
no file open, try 'help open'
+
+== Invalid backing file size ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+qemu-io: can't open device TEST_DIR/t.qcow2: Backing file name too long
+no file open, try 'help open'
*** done