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Posted to dev@sling.apache.org by GitBox <gi...@apache.org> on 2022/09/08 08:06:48 UTC
[GitHub] [sling-org-apache-sling-xss] nonanalou commented on a diff in pull request #28: SLING-7231 Move to owasp sanitizer library
nonanalou commented on code in PR #28:
URL: https://github.com/apache/sling-org-apache-sling-xss/pull/28#discussion_r965637546
##########
src/main/java/org/apache/sling/xss/impl/style/BatikCssCleaner.java:
##########
@@ -0,0 +1,82 @@
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ ~ Licensed to the Apache Software Foundation (ASF) under one
+ ~ or more contributor license agreements. See the NOTICE file
+ ~ distributed with this work for additional information
+ ~ regarding copyright ownership. 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.
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+package org.apache.sling.xss.impl.style;
+
+import java.io.IOException;
+import java.io.StringReader;
+
+import org.apache.batik.css.parser.Parser;
+import org.apache.sling.xss.impl.xml.AntiSamyPolicy.CssPolicy;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.w3c.css.sac.CSSException;
+import org.w3c.css.sac.InputSource;
+
+public class BatikCssCleaner {
+
+ private final Logger logger = LoggerFactory.getLogger(getClass());
+ private final CssPolicy cssPolicy;
+
+ private static final String CDATA_PRE = "<![CDATA[";
+ private static final String CDATA_POST = "]]>";
+
+ public BatikCssCleaner(CssPolicy cssPolicy) {
+ this.cssPolicy = cssPolicy;
+ }
+
+ /**
+ * Parses a CSS stylesheet and returns it in a safe form
+ *
+ * @param untrustedCss a complete CSS stylesheet
+ * @return the cleaned CSS stylesheet text
+ */
+ public String cleanStylesheet(String untrustedCss) {
+ try {
+ if ( untrustedCss.startsWith(CDATA_PRE) && untrustedCss.endsWith(CDATA_POST) )
+ untrustedCss = untrustedCss.substring(CDATA_PRE.length(), untrustedCss.length() - CDATA_POST.length());
+ Parser parser = new Parser();
+ ValidatingDocumentHandler handler = new ValidatingDocumentHandler(cssPolicy, false);
+ parser.setDocumentHandler(handler);
+ parser.parseStyleSheet(new InputSource(new StringReader(untrustedCss)));
+ return handler.getValidCss();
+ } catch (CSSException | IOException e) {
+ logger.debug("Unexpected error while cleaning stylesheet", e);
Review Comment:
This method is called, by the [CSSValidator newCssAttributePolicy Method](https://github.com/apache/sling-org-apache-sling-xss/pull/28/files#diff-6abfffeec1aa36d3bbef5bb53c2a5ace07f61bab8c38b34a5bf11002f8457d4eR45).
And this is an Override of the[ AttributePolicy apply Method](https://github.com/OWASP/java-html-sanitizer/blob/main/src/main/java/org/owasp/html/AttributePolicy.java#L59), which I did not write.
Should i catch it instead in the CSSValidator class?
##########
src/main/java/org/apache/sling/xss/impl/style/BatikCssCleaner.java:
##########
@@ -0,0 +1,82 @@
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ ~ Licensed to the Apache Software Foundation (ASF) under one
+ ~ or more contributor license agreements. See the NOTICE file
+ ~ distributed with this work for additional information
+ ~ regarding copyright ownership. 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.
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+package org.apache.sling.xss.impl.style;
+
+import java.io.IOException;
+import java.io.StringReader;
+
+import org.apache.batik.css.parser.Parser;
+import org.apache.sling.xss.impl.xml.AntiSamyPolicy.CssPolicy;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.w3c.css.sac.CSSException;
+import org.w3c.css.sac.InputSource;
+
+public class BatikCssCleaner {
+
+ private final Logger logger = LoggerFactory.getLogger(getClass());
+ private final CssPolicy cssPolicy;
+
+ private static final String CDATA_PRE = "<![CDATA[";
+ private static final String CDATA_POST = "]]>";
+
+ public BatikCssCleaner(CssPolicy cssPolicy) {
+ this.cssPolicy = cssPolicy;
+ }
+
+ /**
+ * Parses a CSS stylesheet and returns it in a safe form
+ *
+ * @param untrustedCss a complete CSS stylesheet
+ * @return the cleaned CSS stylesheet text
+ */
+ public String cleanStylesheet(String untrustedCss) {
+ try {
+ if ( untrustedCss.startsWith(CDATA_PRE) && untrustedCss.endsWith(CDATA_POST) )
+ untrustedCss = untrustedCss.substring(CDATA_PRE.length(), untrustedCss.length() - CDATA_POST.length());
+ Parser parser = new Parser();
+ ValidatingDocumentHandler handler = new ValidatingDocumentHandler(cssPolicy, false);
+ parser.setDocumentHandler(handler);
+ parser.parseStyleSheet(new InputSource(new StringReader(untrustedCss)));
+ return handler.getValidCss();
+ } catch (CSSException | IOException e) {
+ logger.debug("Unexpected error while cleaning stylesheet", e);
+ return "";
+ }
+ }
+
+ /**
+ * Parses a CSS style declaration (i.e. the text of a <tt>style</tt> attribute) and returns it in a safe form
+ *
+ * @param untrustedCss a css style declaration
+ * @return the cleaned CSS style declaration
+ */
+ public String cleanStyleDeclaration(String untrustedCss) {
+ try {
+ Parser parser = new Parser();
+ ValidatingDocumentHandler handler = new ValidatingDocumentHandler(cssPolicy, true);
+ parser.setDocumentHandler(handler);
+ parser.parseStyleDeclaration(new InputSource(new StringReader(untrustedCss)));
+ return handler.getValidCss();
+ } catch (CSSException | IOException e) {
+ logger.debug("Unexpected error while cleaning style declaration", e);
Review Comment:
What do you mean with Exception handling? Do you mean logger.error() instead of logger.debug()?
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