#528 Implement external access control based on previous PR

Author: danfickle

openhtmltopdf-core/src/main/java/com/openhtmltopdf/extend/UserAgentCallback.java

@@ -19,6 +19,7 @@
  */
 package com.openhtmltopdf.extend;
 
+import com.openhtmltopdf.outputdevice.helper.ExternalResourceType;
 import com.openhtmltopdf.resource.CSSResource;
 import com.openhtmltopdf.resource.ImageResource;
 import com.openhtmltopdf.resource.XMLResource;
@@ -51,29 +52,57 @@ public interface UserAgentCallback {
      * @param uri Location of the CSS
      * @return A CSSResource for the content at the URI.
      */
-    CSSResource getCSSResource(String uri);
+    default CSSResource getCSSResource(String uri) {
+        return getCSSResource(uri, ExternalResourceType.CSS);
+    }
+
+    CSSResource getCSSResource(String uri, ExternalResourceType type);
 
     /**
      * Retrieves the Image at the given URI. This is a synchronous call.
      *
      * @param uri Location of the image
      * @return An ImageResource for the content at the URI.
      */
-    ImageResource getImageResource(String uri);
+    default ImageResource getImageResource(String uri) {
+        return getImageResource(uri, ExternalResourceType.IMAGE_RASTER);
+    }
+
+    ImageResource getImageResource(String uri, ExternalResourceType type);
+
+
+    /**
+     * @deprecated
+     * Use {@link #getXMLResource(String, ExternalResourceType)} instead.
+     */
+    @Deprecated
+    default XMLResource getXMLResource(String uri) {
+        return getXMLResource(uri, ExternalResourceType.XML_XHTML);
+    }
 
     /**
      * Retrieves the XML at the given URI. This is a synchronous call.
      *
      * @param uri Location of the XML
+     * @param type Either xhtml or svg.
      * @return A XMLResource for the content at the URI.
      */
-    XMLResource getXMLResource(String uri);
-    
+    XMLResource getXMLResource(String uri, ExternalResourceType type);
+
+    /**
+     * @deprecated
+     * Use {@link #getBinaryResource(String, ExternalResourceType)} instead.
+     */
+    @Deprecated
+    default byte[] getBinaryResource(String uri) {
+        return getBinaryResource(uri, ExternalResourceType.BINARY);
+    }
+
     /**
      * Retrieves a binary resource located at a given URI and returns its contents
      * as a byte array or <code>null</code> if the resource could not be loaded.
      */
-    byte[] getBinaryResource(String uri);
+    byte[] getBinaryResource(String uri, ExternalResourceType type);
 
     /**
      * Normally, returns true if the user agent has visited this URI. UserAgent should consider

openhtmltopdf-core/src/main/java/com/openhtmltopdf/outputdevice/helper/BaseRendererBuilder.java

@@ -19,6 +19,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.BiPredicate;
 import java.util.function.Consumer;
 
 /**
@@ -37,6 +38,10 @@ public abstract class BaseRendererBuilder<TFinalClass extends BaseRendererBuilde
 	public abstract static class BaseRendererBuilderState {
         public final List<AddedFont> _fonts = new ArrayList<>(); 
         public final List<FSDOMMutator> _domMutators = new ArrayList<>();
+
+        public BiPredicate<String, ExternalResourceType> _beforeAccessController = new NaiveUserAgent.DefaultAccessController();
+        public BiPredicate<String, ExternalResourceType> _afterAccessController = new NaiveUserAgent.DefaultAccessController();
+
         public final Map<String, FSStreamFactory> _streamFactoryMap = new HashMap<>();
 		public FSUriResolver _resolver;
 		public String _html;
@@ -560,6 +565,38 @@ protected Closeable applyDiagnosticConsumer() {
 		return ThreadCtx.applyDiagnosticConsumer(state._diagnosticConsumer);
 	}
 
+    /**
+     * Allows to set <strong>one</strong> external access controller to run
+     * before the uri resolver and one to run after the uri resolver.
+     *
+     * The predicate will receive the uri and the resource type. If it returns
+     * false, the resource will not be loaded but the rendering process will
+     * attempt to continue without the resource.
+     *
+     * A default controller is registered that allows everything except file
+     * embed resources. To override the default controller, register a controller
+     * with after priority.
+     */
+    public TFinalClass useExternalResourceAccessControl(
+            BiPredicate<String, ExternalResourceType> allowExternalResource,
+            ExternalResourceControlPriority priority) {
+        if (priority == null) {
+            // Default is after as safest.
+            priority = ExternalResourceControlPriority.RUN_AFTER_RESOLVING_URI;
+        }
+
+        switch (priority) {
+        case RUN_AFTER_RESOLVING_URI:
+            state._afterAccessController = allowExternalResource;
+            break;
+        case RUN_BEFORE_RESOLVING_URI:
+            state._beforeAccessController = allowExternalResource;
+            break;
+        }
+
+        return (TFinalClass) this;
+    }
+
 	public enum TextDirection {
 		RTL, LTR
 	}

openhtmltopdf-core/src/main/java/com/openhtmltopdf/outputdevice/helper/ExternalResourceControlPriority.java

@@ -0,0 +1,6 @@
+package com.openhtmltopdf.outputdevice.helper;
+
+public enum ExternalResourceControlPriority {
+    RUN_BEFORE_RESOLVING_URI,
+    RUN_AFTER_RESOLVING_URI;
+}

openhtmltopdf-core/src/main/java/com/openhtmltopdf/outputdevice/helper/ExternalResourceType.java

@@ -0,0 +1,13 @@
+package com.openhtmltopdf.outputdevice.helper;
+
+public enum ExternalResourceType {
+    FONT,
+    FILE_EMBED,
+    CSS,
+    IMAGE_RASTER,
+    XML_XHTML,
+    XML_SVG,
+    BINARY,
+    PDF,
+    SVG_BINARY;
+}

openhtmltopdf-core/src/main/java/com/openhtmltopdf/outputdevice/helper/FontFaceFontSupplier.java

@@ -20,7 +20,7 @@ public FontFaceFontSupplier(SharedContext ctx, String src) {
 
     @Override
     public InputStream supply() {
-        byte[] font1 = ctx.getUserAgentCallback().getBinaryResource(src);
+        byte[] font1 = ctx.getUserAgentCallback().getBinaryResource(src, ExternalResourceType.FONT);
 
         if (font1 == null) {
             XRLog.log(Level.WARNING, LogMessageId.LogMessageId1Param.EXCEPTION_COULD_NOT_LOAD_FONT_FACE, src);

openhtmltopdf-core/src/main/java/com/openhtmltopdf/swing/NaiveUserAgent.java

@@ -26,9 +26,11 @@
 import java.net.URISyntaxException;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
+import java.util.EnumMap;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.function.BiPredicate;
 import java.util.logging.Level;
 
 import javax.imageio.ImageIO;
@@ -38,6 +40,8 @@
 import com.openhtmltopdf.extend.FSStreamFactory;
 import com.openhtmltopdf.extend.FSStream;
 import com.openhtmltopdf.extend.UserAgentCallback;
+import com.openhtmltopdf.outputdevice.helper.ExternalResourceControlPriority;
+import com.openhtmltopdf.outputdevice.helper.ExternalResourceType;
 import com.openhtmltopdf.resource.CSSResource;
 import com.openhtmltopdf.resource.ImageResource;
 import com.openhtmltopdf.resource.XMLResource;
@@ -63,6 +67,8 @@ public class NaiveUserAgent implements UserAgentCallback, DocumentListener {
     protected final LinkedHashMap<String, ImageResource> _imageCache = new LinkedHashMap<>();
     protected final FSUriResolver DEFAULT_URI_RESOLVER = new DefaultUriResolver(); 
 
+    protected final Map<ExternalResourceControlPriority, BiPredicate<String, ExternalResourceType>> _accessControllers = new EnumMap<>(ExternalResourceControlPriority.class);
+
     protected FSUriResolver _resolver = DEFAULT_URI_RESOLVER;
     protected String _baseUri;
 	protected Map<String, FSStreamFactory> _protocolsStreamFactory = new HashMap<>(2);
@@ -266,9 +272,15 @@ protected String readAll(Reader reader) throws IOException {
      * @return A CSSResource containing the CSS reader or null if not available.
      */
     @Override
-    public CSSResource getCSSResource(String uri) {
+    public CSSResource getCSSResource(String uri, ExternalResourceType type) {
+        if (!checkAccessAllowed(uri, type, ExternalResourceControlPriority.RUN_BEFORE_RESOLVING_URI)) {
+            return null;
+        }
     	String resolved = _resolver.resolveURI(this._baseUri, uri);
-    	
+        if (!checkAccessAllowed(resolved, type, ExternalResourceControlPriority.RUN_AFTER_RESOLVING_URI)) {
+            return null;
+        }
+
     	if (resolved == null) {
     		XRLog.log(Level.INFO, LogMessageId.LogMessageId2Param.LOAD_URI_RESOLVER_REJECTED_LOADING_AT_URI, "CSS resource", uri);
     		return null;
@@ -286,11 +298,16 @@ public CSSResource getCSSResource(String uri) {
      * @return An ImageResource containing the image.
      */
     @Override
-    public ImageResource getImageResource(String uri) {
+    public ImageResource getImageResource(String uri, ExternalResourceType type) {
         ImageResource ir;
-        
 
+        if (!checkAccessAllowed(uri, type, ExternalResourceControlPriority.RUN_BEFORE_RESOLVING_URI)) {
+            return null;
+        }
 		String resolved = _resolver.resolveURI(this._baseUri, uri);
+        if (!checkAccessAllowed(resolved, type, ExternalResourceControlPriority.RUN_AFTER_RESOLVING_URI)) {
+            return null;
+        }
 
 		if (resolved == null) {
 			XRLog.log(Level.INFO, LogMessageId.LogMessageId2Param.LOAD_URI_RESOLVER_REJECTED_LOADING_AT_URI, "image resource", uri);
@@ -345,9 +362,15 @@ public ImageResource getImageResource(String uri) {
      * @return An XMLResource containing the image.
      */
     @Override
-    public XMLResource getXMLResource(String uri) {
+    public XMLResource getXMLResource(String uri, ExternalResourceType type) {
+        if (!checkAccessAllowed(uri, type, ExternalResourceControlPriority.RUN_BEFORE_RESOLVING_URI)) {
+            return null;
+        }
     	String resolved = _resolver.resolveURI(this._baseUri, uri);
-    	
+        if (!checkAccessAllowed(resolved, type, ExternalResourceControlPriority.RUN_AFTER_RESOLVING_URI)) {
+            return null;
+        }
+
     	if (resolved == null) {
     		XRLog.log(Level.INFO, LogMessageId.LogMessageId2Param.LOAD_URI_RESOLVER_REJECTED_LOADING_AT_URI, "XML resource", uri);
     		return null;
@@ -363,9 +386,15 @@ public XMLResource getXMLResource(String uri) {
     }
 
     @Override
-    public byte[] getBinaryResource(String uri) {
+    public byte[] getBinaryResource(String uri, ExternalResourceType type) {
+        if (!checkAccessAllowed(uri, type, ExternalResourceControlPriority.RUN_BEFORE_RESOLVING_URI)) {
+            return null;
+        }
         String resolved = _resolver.resolveURI(this._baseUri, uri);
-    	
+        if (!checkAccessAllowed(resolved, type, ExternalResourceControlPriority.RUN_AFTER_RESOLVING_URI)) {
+            return null;
+        }
+
     	if (resolved == null) {
 			XRLog.log(Level.INFO, LogMessageId.LogMessageId2Param.LOAD_URI_RESOLVER_REJECTED_LOADING_AT_URI, "binary resource", uri);
     		return null;
@@ -422,6 +451,61 @@ public void setBaseURL(String uri) {
         _baseUri = uri;
     }
 
+    public static class DefaultAccessController
+                  implements BiPredicate<String, ExternalResourceType> {
+
+        public boolean test(String uri, ExternalResourceType resourceType) {
+            if (resourceType == null) {
+                return false;
+            }
+
+            switch (resourceType) {
+            case BINARY:
+            case CSS:
+            case FONT:
+            case IMAGE_RASTER:
+            case XML_XHTML:
+            case XML_SVG:
+            case PDF:
+            case SVG_BINARY:
+                return true;
+            case FILE_EMBED:
+                return false;
+            }
+
+            return false;
+        }
+    }
+
+    public void setAccessController(
+            ExternalResourceControlPriority prio,
+            BiPredicate<String, ExternalResourceType> controller) {
+        this._accessControllers.put(prio, controller);
+    }
+
+    public boolean checkAccessAllowed(
+            String uriOrResolved,
+            ExternalResourceType type,
+            ExternalResourceControlPriority priority) {
+        BiPredicate<String, ExternalResourceType> controller = this._accessControllers.get(priority);
+
+        if (uriOrResolved == null) {
+            return false;
+        }
+
+        if (controller == null) {
+            return true;
+        }
+
+        boolean passed = controller.test(uriOrResolved, type);
+
+        if (!passed) {
+            XRLog.log(Level.WARNING, LogMessageId.LogMessageId2Param.LOAD_RESOURCE_ACCESS_REJECTED, uriOrResolved, type);
+        }
+
+        return passed;
+    }
+
     public static class DefaultUriResolver implements FSUriResolver {
 		/**
 		 * Resolves the URI; if absolute, leaves as is, if relative, returns an

openhtmltopdf-core/src/main/java/com/openhtmltopdf/util/LogMessageId.java

@@ -217,6 +217,7 @@ enum LogMessageId2Param implements LogMessageId {
         LOAD_URI_RESOLVER_REJECTED_LOADING_AT_URI(XRLog.LOAD, "URI resolver rejected loading {} at ({})"),
         LOAD_COULD_NOT_READ_URI_AT_URL_MAY_BE_RELATIVE(XRLog.LOAD, "Could not read {} as a URL; may be relative. Testing using parent URL {}"),
         LOAD_WAS_ABLE_TO_READ_FROM_URI_USING_PARENT_URL(XRLog.LOAD, "Was able to read from {} using parent URL {}"),
+        LOAD_RESOURCE_ACCESS_REJECTED(XRLog.LOAD, "URI {} with type {} was rejected by resource access controller"),
 
         GENERAL_FATAL_INFINITE_LOOP_BUG_IN_LINE_BREAKING_ALGO(XRLog.GENERAL, "A fatal infinite loop bug was detected in the line breaking " +
                 "algorithm for break-word! Start-substring=[{}], end={}"),

openhtmltopdf-examples/src/main/resources/visualtest/expected/external-access-control.pdf

@@ -0,0 +1,14 @@
+<html>
+<head>
+<style>
+@page {
+  size: 200px 200px;
+}
+</style>
+<link rel="stylesheet" href="stylesheets/basic.css" />
+</head>
+<body>
+<div id="one">RED</div>
+<div id="two">BLUE</div>
+</body>
+</html>

openhtmltopdf-examples/src/main/resources/visualtest/html/external-access-control.html

@@ -0,0 +1 @@
+div#one { color: red; }