Remove ole objects

module/module-office/src/main/java/xyz/docbleach/module/ooxml/OOXMLBleach.java

@@ -205,6 +205,7 @@ public void sanitize(OPCPackage pkg, BleachSession session)
       sanitize(session, pkg, part);
 
       OOXMLTagHelper.removeExternalDataTagAndDDE(session, part);
+      OOXMLoleObjectsHelper.removeoleObjects(session, part);
 
       if (!part.isRelationshipPart()) {
         sanitize(session, part, part.getRelationships());

module/module-office/src/main/java/xyz/docbleach/module/ooxml/OOXMLoleObjectsHelper.java

@@ -0,0 +1,119 @@
+package xyz.docbleach.module.ooxml;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+import org.apache.poi.openxml4j.opc.PackagePart;
+import org.apache.poi.openxml4j.opc.ZipPackagePart;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import xyz.docbleach.api.BleachSession;
+import xyz.docbleach.api.threat.Threat;
+import xyz.docbleach.api.threat.ThreatAction;
+import xyz.docbleach.api.threat.ThreatSeverity;
+import xyz.docbleach.api.threat.ThreatType;
+
+/**
+ * Helper dedicated to alter XML oleObjects.
+ */
+public class OOXMLoleObjectsHelper {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(OOXMLoleObjectsHelper.class);
+
+  private static final String XML_EXTENSION = "xml";
+  private static final String XML_COMMENT_BLEACHED = "<!-- bleached -->";
+  private static final String OLEOBJECTS_DATA = "oleObjects";
+
+  /**
+   * The regexp tries to catch the whole element, including namespace and attributes
+   */
+  private static final String REGEXP_OLEOBJECTS_DATA = "<" + OLEOBJECTS_DATA + ".*?/" + OLEOBJECTS_DATA + ">";
+
+
+  private OOXMLoleObjectsHelper() {
+  }
+
+  /**
+   * oleObjects are embedded in xml files. Remove these objects to prevent MS Office from crashing after bleaching.
+   *
+   * @param session The current bleach session where the threat can be reported
+   * @param part The package part to sanitize
+   */
+  protected static void removeoleObjects(BleachSession session, PackagePart part) {
+    // Only applicable if the file is an XML file (not a _refs or whatever)
+    // And is a ZipPackagePart, not a config file or whatever.
+    if (!XML_EXTENSION.equals(part.getPartName().getExtension())
+        || !(part instanceof ZipPackagePart)) {
+      return;
+    }
+
+    String content = readPartContent(part);
+    // An error occured
+    if (content == null) {
+      return;
+    }
+
+    boolean oleobject = content.indexOf(OLEOBJECTS_DATA) != -1;
+
+
+    // oleObjects have not been found, return
+    if (!oleobject) {
+      return;
+    }
+
+    LOGGER.debug("oleObjects have been spotted {}", part);
+
+    // Replace the oleObject by a comment
+    content = content.replaceAll(REGEXP_OLEOBJECTS_DATA, XML_COMMENT_BLEACHED);
+
+
+    // Write the result
+    try (OutputStream os = part.getOutputStream()) {
+      os.write(content.getBytes());
+      os.close();
+    } catch (IOException ex) {
+      LOGGER.error("Error while writing the part content. The file may be corrupted.", ex);
+      return;
+    }
+
+    session.recordThreat(Threat.builder()
+        .type(ThreatType.ACTIVE_CONTENT)
+        .severity(ThreatSeverity.HIGH)
+        .action(ThreatAction.REMOVE)
+        .location(part.getPartName().getName())
+        .details("Removed oleObjects from the document.")
+        .build());
+  }
+
+  /**
+   * Read the part content.
+   *
+   * @param part The {@link org.apache.poi.openxml4j.opc.PackagePart PackagePart} the content must
+   * be read from
+   * @return A string containing the content of the part.
+   */
+  private static String readPartContent(PackagePart part) {
+    try (InputStream is = part.getInputStream()) {
+      // Read the file content first
+      BufferedReader reader = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8));
+
+      StringBuilder buf = new StringBuilder();
+      String line = reader.readLine();
+      while (line != null) {
+        buf.append(line);
+        line = reader.readLine();
+      }
+
+      return buf.toString();
+    } catch (IOException ex) {
+      LOGGER.error(
+          "Error while bleaching {}. The file may be corrupted :/",
+          part.getPartName().getName(),
+          ex);
+      return null;
+    }
+  }
+}