ppkarwasz commented on code in PR #198: URL: https://github.com/apache/roller/pull/198#discussion_r4218736314
########## app/src/main/java/org/apache/roller/weblogger/webservices/atomprotocol/RollerAtomServlet.java: ########## @@ -0,0 +1,237 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. The ASF licenses this file to You + * under the Apache License, Version 2.0 (the "License"); you may not + * use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. For additional information regarding + * copyright in this work, please see the NOTICE file in the top level + * directory of this distribution. + */ + +package org.apache.roller.weblogger.webservices.atomprotocol; + +import java.io.BufferedReader; +import java.io.ByteArrayInputStream; +import java.io.IOException; +import java.io.InputStreamReader; +import java.nio.charset.StandardCharsets; +import javax.xml.parsers.ParserConfigurationException; +import javax.servlet.ReadListener; +import javax.servlet.ServletException; +import javax.servlet.ServletInputStream; +import javax.servlet.http.HttpServletRequest; +import javax.servlet.http.HttpServletRequestWrapper; +import javax.servlet.http.HttpServletResponse; + +import com.rometools.propono.atom.server.AtomHandler; +import com.rometools.propono.atom.server.AtomServlet; +import org.apache.commons.logging.Log; +import org.apache.commons.logging.LogFactory; +import org.apache.roller.weblogger.config.WebloggerRuntimeConfig; +import org.apache.roller.weblogger.util.SecureXmlParsers; +import org.xml.sax.InputSource; +import org.xml.sax.SAXException; +import org.xml.sax.SAXParseException; +import org.xml.sax.XMLReader; +import org.xml.sax.helpers.DefaultHandler; + +/** + * Roller's AtomPub endpoint. It answers only while + * <code>webservices.enableAtomPub</code> is on, and it reads each Atom entry + * body with Roller's shared XML parser settings before the Propono servlet + * handles the request. + */ +public class RollerAtomServlet extends AtomServlet { + + private static final long serialVersionUID = 1L; + + private static final Log LOG = LogFactory.getLog(RollerAtomServlet.class); + + /** Default maximum Atom entry body size, in bytes. Media uploads are not affected. */ + static final int DEFAULT_MAX_ENTRY_BYTES = 1024 * 1024; + + static final String MAX_ENTRY_SIZE_PROPERTY = "webservices.atomPubMaxEntrySize"; + + private static final String ATOM_CONTENT_TYPE = "application/atom+xml"; + + /** + * Request attribute that carries the handler authenticated by this servlet + * to {@link RollerAtomHandlerFactory}, so Propono does not authenticate the + * request a second time. + */ + static final String HANDLER_ATTRIBUTE = RollerAtomServlet.class.getName() + ".handler"; + + @Override + protected void service(HttpServletRequest req, HttpServletResponse res) + throws ServletException, IOException { + + if (!WebloggerRuntimeConfig.getBooleanProperty("webservices.enableAtomPub")) { + LOG.debug("AtomPub service is disabled; rejecting request"); + sendText(res, HttpServletResponse.SC_NOT_FOUND, "AtomPub service is disabled"); + return; + } + + if (!carriesEntry(req)) { + forward(req, res); + return; + } + + // Authenticate before reading the body, as Propono does. + AtomHandler handler = createHandler(req, res); + if (handler.getAuthenticatedUsername() == null) { + res.setHeader("WWW-Authenticate", "BASIC realm=\"AtomPub\""); + res.sendError(HttpServletResponse.SC_UNAUTHORIZED); + return; + } + req.setAttribute(HANDLER_ATTRIBUTE, handler); + + int maxEntryBytes = maxEntryBytes(); + // Read one byte past the limit, so an oversized body can be detected. + byte[] body = req.getInputStream().readNBytes(maxEntryBytes + 1); + if (body.length > maxEntryBytes) { + sendText(res, HttpServletResponse.SC_REQUEST_ENTITY_TOO_LARGE, "Entry is too large"); + return; + } + DefaultHandler contentHandler = new DefaultHandler() { + @Override + public void error(SAXParseException e) throws SAXException { + throw e; + } + }; + XMLReader reader; + try { + reader = SecureXmlParsers.newSAXParserFactory().newSAXParser().getXMLReader(); Review Comment: _Nitpick_: I would still reject DOCTYPE explicitly here either with a `LexicalHandler` (for a personalized exception and/or Android compatibility) or `disable-doctype-decl`. The contract of `SecureXmlParsers.newSAXParserFactory()` does not need to include `DOCTYPE` rejection: any other hardening measure is good enough. In this particular case we need to reject it to workaround a problem in an upstream EOL-ed artifact. ```suggestion reader = SecureXmlParsers.newSAXParserFactory().newSAXParser().getXMLReader(); // Hardening: DOCTYPE declarations should be rejected, // regardless whether the secure reader already does it. DefaultHandler2 doctypeRefuser = new DefaultHandler2() { @Override public void startDTD(String name, String publicId, String systemId) throws SAXException { throw new SAXException("DOCTYPE is not allowed in an Atom entry"); } }; parser.setProperty("http://xml.org/sax/properties/lexical-handler";, doctypeRefuser); ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
