Author: toad
Date: 2006-12-02 16:48:30 +0000 (Sat, 02 Dec 2006)
New Revision: 11195
Added:
trunk/freenet/src/freenet/clients/http/filter/GIFFilter.java
Modified:
trunk/freenet/src/freenet/clients/http/filter/ContentFilter.java
Log:
Basic GIF filter too. (Again, this only checks the header).
Modified: trunk/freenet/src/freenet/clients/http/filter/ContentFilter.java
===================================================================
--- trunk/freenet/src/freenet/clients/http/filter/ContentFilter.java
2006-12-02 16:42:54 UTC (rev 11194)
+++ trunk/freenet/src/freenet/clients/http/filter/ContentFilter.java
2006-12-02 16:48:30 UTC (rev 11195)
@@ -39,7 +39,7 @@
// GIF - probably safe - FIXME check this out, write filters
register(new MIMEType("image/gif", "gif", new String[0], new
String[0],
- true, false, null, null, false, false, false,
false, false, false,
+ true, false, new GIFFilter(), null, false,
false, false, false, false, false,
"GIF image - probably not dangerous",
"GIF image - probably not dangerous but you
should wipe any comments",
false, null, null));
Added: trunk/freenet/src/freenet/clients/http/filter/GIFFilter.java
===================================================================
--- trunk/freenet/src/freenet/clients/http/filter/GIFFilter.java
2006-12-02 16:42:54 UTC (rev 11194)
+++ trunk/freenet/src/freenet/clients/http/filter/GIFFilter.java
2006-12-02 16:48:30 UTC (rev 11195)
@@ -0,0 +1,75 @@
+/* This code is part of Freenet. It is distributed under the GNU General
+ * Public License, version 2 (or at your option any later version). See
+ * http://www.gnu.org/ for further details of the GPL. */
+package freenet.clients.http.filter;
+
+import java.io.BufferedInputStream;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.HashMap;
+
+import freenet.support.HTMLNode;
+import freenet.support.io.Bucket;
+import freenet.support.io.BucketFactory;
+
+/**
+ * Content filter for PNG's.
+ * This one just verifies that a PNG is valid, and throws if it isn't.
+ */
+public class GIFFilter implements ContentDataFilter {
+
+ static final String ERROR_MESSAGE =
+ "The file you tried to fetch is not a GIF. It does not include
a valid GIF header. "+
+ "It might be some other file format, and your browser may do
something horrible with it, "+
+ "therefore we have blocked it.";
+
+ static final int HEADER_SIZE = 6;
+ static final byte[] gif87aHeader =
+ { (byte)'G', (byte)'I', (byte)'F', (byte)'8', (byte)'7',
(byte)'a' };
+ static final byte[] gif89aHeader =
+ { (byte)'G', (byte)'I', (byte)'F', (byte)'8', (byte)'9',
(byte)'a' };
+
+
+ public Bucket readFilter(Bucket data, BucketFactory bf, String charset,
+ HashMap otherParams, FilterCallback cb) throws
DataFilterException,
+ IOException {
+ if(data.size() < 6) {
+ throwHeaderError("Too short", "The file is too short to
be a GIF.");
+ }
+ InputStream is = data.getInputStream();
+ BufferedInputStream bis = new BufferedInputStream(is);
+ DataInputStream dis = new DataInputStream(bis);
+ try {
+ // Check the header
+ byte[] headerCheck = new byte[HEADER_SIZE];
+ dis.read(headerCheck);
+ if((!Arrays.equals(headerCheck, gif87aHeader)) &&
(!Arrays.equals(headerCheck, gif89aHeader))) {
+ throwHeaderError("Invalid header", "The file
does not contain a valid GIF header.");
+ }
+ } finally {
+ dis.close();
+ }
+ return data;
+ }
+
+ private void throwHeaderError(String shortReason, String reason) throws
DataFilterException {
+ // Throw an exception
+ String message = ERROR_MESSAGE;
+ if(reason != null) message += ' ' + reason;
+ String msg = "Not a GIF";
+ if(shortReason != null)
+ msg += " - " + shortReason;
+ throw new DataFilterException(shortReason, shortReason,
+ "<p>"+message+"</p>", new
HTMLNode("p").addChild("#", message));
+ }
+
+ public Bucket writeFilter(Bucket data, BucketFactory bf, String charset,
+ HashMap otherParams, FilterCallback cb) throws
DataFilterException,
+ IOException {
+ // TODO Auto-generated method stub
+ return null;
+ }
+
+}
