Verify QCOW2 features on direct download of template

Author: GutoVeronezi

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/KVMStorageProcessor.java

@@ -26,6 +26,7 @@
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
@@ -63,6 +64,7 @@
 import org.apache.cloudstack.storage.command.SnapshotAndCopyAnswer;
 import org.apache.cloudstack.storage.command.SnapshotAndCopyCommand;
 import org.apache.cloudstack.storage.command.SyncVolumePathCommand;
+import org.apache.cloudstack.storage.formatinspector.Qcow2Inspector;
 import org.apache.cloudstack.storage.to.PrimaryDataStoreTO;
 import org.apache.cloudstack.storage.to.SnapshotObjectTO;
 import org.apache.cloudstack.storage.to.TemplateObjectTO;
@@ -2394,6 +2396,22 @@ public Answer handleDownloadTemplateToPrimaryStorage(DirectDownloadCommand cmd)
 
             template = storagePoolMgr.createPhysicalDiskFromDirectDownloadTemplate(tempFilePath, destTemplatePath, destPool, cmd.getFormat(), cmd.getWaitInMillSeconds());
 
+            String templatePath = template.getPath();
+            if (templatePath != null) {
+                try {
+                    Qcow2Inspector.validateQcow2File(templatePath);
+                } catch (RuntimeException e) {
+                    try {
+                        Files.deleteIfExists(Path.of(templatePath));
+                    } catch (IOException ioException) {
+                        s_logger.warn(String.format("Unable to remove file [%s]; consider removing it manually.", templatePath), ioException);
+                    }
+
+                    s_logger.error(String.format("The downloaded file [%s] is not a valid QCOW2.", templatePath), e);
+                    return new DirectDownloadAnswer(false, "The downloaded file is not a valid QCOW2. Ask the administrator to check the logs for more details.", true);
+                }
+            }
+
             if (!storagePoolMgr.disconnectPhysicalDisk(pool.getPoolType(), pool.getUuid(), destTemplatePath)) {
                 s_logger.warn("Unable to disconnect physical disk at path: " + destTemplatePath + ", in storage pool id: " + pool.getUuid());
             }