vmdk: Check for overhead when opening

Report an error if file size is even smaller than metadata.
Signed-off-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/vmdk.c

@@ -640,6 +640,13 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
     if (le32_to_cpu(header.flags) & VMDK4_FLAG_RGD) {
         l1_backup_offset = le64_to_cpu(header.rgd_offset) << 9;
     }
+    if (bdrv_getlength(file) <
+            le64_to_cpu(header.grain_offset) * BDRV_SECTOR_SIZE) {
+        error_report("File truncated, expecting at least %lld bytes",
+                le64_to_cpu(header.grain_offset) * BDRV_SECTOR_SIZE);
+        return -EINVAL;
+    }
+
     ret = vmdk_add_extent(bs, file, false,
                           le64_to_cpu(header.capacity),
                           le64_to_cpu(header.gd_offset) << 9,

tests/qemu-iotests/059

@@ -97,6 +97,12 @@ RW 12582912 VMFS "dummy.vmdk" 1
 EOF
 _img_info
 
+echo
+echo "=== Testing truncated sparse ==="
+IMGOPTS="subformat=monolithicSparse" _make_test_img 100G
+truncate -s 10M $TEST_IMG
+_img_info
+
 echo
 echo "=== Testing version 3 ==="
 _use_sample_img iotest-version3.vmdk.bz2

tests/qemu-iotests/059.out

@@ -2043,6 +2043,11 @@ qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Invalid extent lines:
 RW 12582912 VMFS "dummy.IMGFMT" 1
 
 
+=== Testing truncated sparse ===
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=107374182400
+qemu-img: File truncated, expecting at least 13172736 bytes
+qemu-img: Could not open 'TEST_DIR/t.IMGFMT': Could not open 'TEST_DIR/t.IMGFMT': Wrong medium type
+
 === Testing version 3 ===
 image: TEST_DIR/iotest-version3.IMGFMT
 file format: IMGFMT