From 041a1859b09b6b04e5bca0be08831555b2075539 Mon Sep 17 00:00:00 2001
From: Ian Young <ian@iay.org.uk>
Date: Tue, 10 Mar 2020 13:51:19 +0000
Subject: [PATCH] Warn and remove long imported mdui:Logo elements; initial
 threshold 50000

---
 mdx/common-beans.xml           | 22 ++++++++++
 mdx/strip-mdui-logo-length.xsl | 74 ++++++++++++++++++++++++++++++++++
 2 files changed, 96 insertions(+)
 create mode 100644 mdx/strip-mdui-logo-length.xsl

diff --git a/mdx/common-beans.xml b/mdx/common-beans.xml
index 8c2df771..12c31340 100644
--- a/mdx/common-beans.xml
+++ b/mdx/common-beans.xml
@@ -853,6 +853,22 @@
         <property name="elementName" value="UIInfo"/>
     </bean>
 
+    <!--
+        strip_mdui_logo_length
+
+        Filter out mdui:Logo elements whose text content is
+        longer than a threshold value. Add a warning to the
+        entity when this is done.
+    -->
+    <bean id="strip_mdui_logo_length" parent="mda.XSLTransformationStage"
+        p:XSLResource="classpath:strip-mdui-logo-length.xsl">
+        <property name="transformParameters">
+            <map>
+                <entry key="maxLength" value="${mdui.logo.length.remove:50000}"/>
+            </map>
+        </property>
+    </bean>
+
     <!--
         *****************************************************
         ***                                               ***
@@ -1193,12 +1209,18 @@
                     </property>
                 </bean>
 
+                <!--
+                    Stages that modify metadata come first, so that
+                    anything they remove is not checked later.
+                -->
                 <ref bean="cleanImport"/>
                 <ref bean="wrapX509Certificates"/>
                 <ref bean="stripAAMDUI"/>
                 <ref bean="stripMDUILogoHttp"/>
                 <ref bean="trimImportElementWhitespace"/>
                 <ref bean="stripEmptyExtensions"/>
+                <ref bean="strip_mdui_logo_length"/>
+
                 <ref bean="checkSchemas"/>
                 <ref bean="CHECK_std"/>
                 <ref bean="check_dup_display"/>
diff --git a/mdx/strip-mdui-logo-length.xsl b/mdx/strip-mdui-logo-length.xsl
new file mode 100644
index 00000000..18544d73
--- /dev/null
+++ b/mdx/strip-mdui-logo-length.xsl
@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    strip-mdui-logo-length.xsl
+
+    Filters out mdui:Logo elements with lengths longer than a
+    provided threshold, and warns that this has been done.
+-->
+<xsl:stylesheet version="1.0"
+    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+    xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
+    xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
+    xmlns:mdui="urn:oasis:names:tc:SAML:metadata:ui"
+    xmlns:mdxURL="xalan://uk.ac.sdss.xalan.md.URLchecker"
+    xmlns:set="http://exslt.org/sets"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="urn:oasis:names:tc:SAML:2.0:metadata">
+
+    <!--
+        Common support functions.
+    -->
+    <xsl:import href="_rules/check_framework.xsl"/>
+
+    <!--
+        maxLength
+
+        This parameter determines the maximum allowable mdui:Logo length
+        before taking action.
+    -->
+    <xsl:param name="maxLength"/>
+
+    <!-- Force UTF-8 encoding for the output. -->
+    <xsl:output omit-xml-declaration="no" method="xml" encoding="UTF-8" indent="yes"/>
+    
+    <!--
+        Match mdui:Logo elements whose string length is greater than the
+        threshold value; issue a warning for them.
+
+        Template match expressions can't include parameter references, so
+        match all mdui:Logo elements then dig in with a conditional.
+    -->
+    <xsl:template match="mdui:Logo">
+        <xsl:choose>
+            <xsl:when test="string-length(.) > $maxLength">
+                <xsl:call-template name="warning">
+                    <xsl:with-param name="m">
+                        <xsl:text>removed mdui:Logo with long contents: </xsl:text>
+                        <xsl:value-of select="string-length(.)"/>
+                        <xsl:text> > </xsl:text>
+                        <xsl:value-of select="$maxLength"/>
+                    </xsl:with-param>
+                </xsl:call-template>
+            </xsl:when>
+            <xsl:otherwise>
+                <xsl:copy>
+                    <xsl:apply-templates select="node()|@*"/>
+                </xsl:copy>
+            </xsl:otherwise>
+        </xsl:choose>
+    </xsl:template>
+
+    <!--By default, copy text blocks, comments and attributes unchanged.-->
+    <xsl:template match="text()|comment()|@*">
+        <xsl:copy/>
+    </xsl:template>
+
+    <!-- Copy all elements from the input to the output, along with their attributes and contents. -->
+    <xsl:template match="*">
+        <xsl:copy>
+            <xsl:apply-templates select="node()|@*"/>
+        </xsl:copy>
+    </xsl:template>
+    
+</xsl:stylesheet>