From ed34f4b59dce226700bf849098b367103065cc69 Mon Sep 17 00:00:00 2001
From: Björn Mattsson <bjorn@sunet.se>
Date: Fri, 13 Jan 2023 09:05:55 +0100
Subject: Added checks for invalid algorithms that UK complains about

---
 xslt/check_uk_algorithms.xsl | 195 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 195 insertions(+)
 create mode 100644 xslt/check_uk_algorithms.xsl

(limited to 'xslt/check_uk_algorithms.xsl')

diff --git a/xslt/check_uk_algorithms.xsl b/xslt/check_uk_algorithms.xsl
new file mode 100644
index 00000000..0a4c024f
--- /dev/null
+++ b/xslt/check_uk_algorithms.xsl
@@ -0,0 +1,195 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    check_uk_algorithms.xsl
+
+    Checking ruleset for cryptographic algorithms. This is named as a UK
+    ruleset because the division between acceptable and unacceptable algorithms
+    is sometimes a judgement call; however, it should be generally
+    applicable.
+
+    The best reference for *all* URIs used as algorithm identifiers is the
+    XML Security Algorithm Cross-Reference at http://www.w3.org/TR/xmlsec-algorithms/
+    Algorithm lists here are in the same order as in that document.
+
+    Author: Ian A. Young <ian@iay.org.uk>
+-->
+<xsl:stylesheet version="1.0"
+    xmlns:alg="urn:oasis:names:tc:SAML:metadata:algsupport"
+    xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+    xmlns="urn:oasis:names:tc:SAML:2.0:metadata">
+
+    <!--
+        Common support functions.
+    -->
+    <xsl:import href="check_framework.xsl"/>
+
+    <!--
+        *************************************
+        ***                               ***
+        ***   S I G N I N G M E T H O D   ***
+        ***                               ***
+        *************************************
+    -->
+
+    <!--
+        Check for known BAD SigningMethod algorithms.
+    -->
+    <xsl:template match="alg:SigningMethod[
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#rsa-md5'
+        ]">
+        <xsl:call-template name="error">
+            <xsl:with-param name="m">
+                <xsl:text>insecure algorithm in SigningMethod: '</xsl:text>
+                <xsl:value-of select="@Algorithm"/>
+                <xsl:text>'</xsl:text>
+            </xsl:with-param>
+        </xsl:call-template>
+    </xsl:template>
+
+    <!--
+        Check for known GOOD SigningMethod algorithms.
+    -->
+    <xsl:template match="alg:SigningMethod[
+        @Algorithm = 'http://www.w3.org/2000/09/xmldsig#dsa-sha1' or
+        @Algorithm = 'http://www.w3.org/2009/xmldsig11#dsa-sha256' or
+        @Algorithm = 'http://www.w3.org/2000/09/xmldsig#rsa-sha1' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha224' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha256' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha384' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#rsa-sha512' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#rsa-ripemd160' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha1' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha224' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha256' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha384' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha512'
+        ]">
+        <!-- do nothing -->
+    </xsl:template>
+
+    <!--
+        Misspelled or otherwise not known SigningMethod algorithms.
+    -->
+    <xsl:template match="alg:SigningMethod">
+        <xsl:call-template name="error">
+            <xsl:with-param name="m">
+                <xsl:text>unknown algorithm in SigningMethod: '</xsl:text>
+                <xsl:value-of select="@Algorithm"/>
+                <xsl:text>'</xsl:text>
+            </xsl:with-param>
+        </xsl:call-template>
+    </xsl:template>
+
+    <!--
+        ***********************************
+        ***                             ***
+        ***   D I G E S T M E T H O D   ***
+        ***                             ***
+        ***********************************
+    -->
+
+    <!--
+        Check for known BAD DigestMethod algorithms.
+    -->
+    <xsl:template match="alg:DigestMethod[
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#md5'
+        ]">
+        <xsl:call-template name="error">
+            <xsl:with-param name="m">
+                <xsl:text>insecure algorithm in DigestMethod: '</xsl:text>
+                <xsl:value-of select="@Algorithm"/>
+                <xsl:text>'</xsl:text>
+            </xsl:with-param>
+        </xsl:call-template>
+    </xsl:template>
+
+    <!--
+        Check for known GOOD DigestMethod algorithms.
+    -->
+    <xsl:template match="alg:DigestMethod[
+        @Algorithm = 'http://www.w3.org/2000/09/xmldsig#sha1' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#sha224' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmlenc#sha256' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmldsig-more#sha384' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmlenc#sha512' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmlenc#ripemd160'
+        ]">
+        <!-- do nothing -->
+    </xsl:template>
+
+    <!--
+        Misspelled or otherwise not known DigestMethod algorithms.
+    -->
+    <xsl:template match="alg:DigestMethod">
+        <xsl:call-template name="error">
+            <xsl:with-param name="m">
+                <xsl:text>unknown algorithm in DigestMethod: '</xsl:text>
+                <xsl:value-of select="@Algorithm"/>
+                <xsl:text>'</xsl:text>
+            </xsl:with-param>
+        </xsl:call-template>
+    </xsl:template>
+
+    <!--
+        *******************************************
+        ***                                     ***
+        ***   E N C R Y P T I O N M E T H O D   ***
+        ***                                     ***
+        *******************************************
+    -->
+
+    <!--
+        Check for known BAD EncryptionMethod algorithms.
+
+        This list is of symmetric key encryption algorithms *and*
+        key transport algorithms.
+    -->
+    <xsl:template match="md:EncryptionMethod[
+        @Algorithm = 'http://www.w3.org/2001/04/xmlenc#rsa-1_5'
+        ]">
+        <xsl:call-template name="error">
+            <xsl:with-param name="m">
+                <xsl:text>insecure algorithm in EncryptionMethod: '</xsl:text>
+                <xsl:value-of select="@Algorithm"/>
+                <xsl:text>'</xsl:text>
+            </xsl:with-param>
+        </xsl:call-template>
+    </xsl:template>
+
+    <!--
+        Check for known GOOD EncryptionMethod algorithms.
+
+        This list is of symmetric key encryption algorithms *and*
+        key transport algorithms.
+    -->
+    <xsl:template match="md:EncryptionMethod[
+        @Algorithm = 'http://www.w3.org/2001/04/xmlenc#tripledes-cbc' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmlenc#aes128-cbc' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmlenc#aes192-cbc' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmlenc#aes256-cbc' or
+        @Algorithm = 'http://www.w3.org/2009/xmlenc11#aes128-gcm' or
+        @Algorithm = 'http://www.w3.org/2009/xmlenc11#aes192-gcm' or
+        @Algorithm = 'http://www.w3.org/2009/xmlenc11#aes256-gcm' or
+        @Algorithm = 'http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p' or
+        @Algorithm = 'http://www.w3.org/2009/xmlenc11#rsa-oaep'
+        ]">
+        <!-- do nothing -->
+    </xsl:template>
+
+    <!--
+        Misspelled or otherwise not known EncryptionMethod algorithms.
+    -->
+    <xsl:template match="md:EncryptionMethod">
+        <xsl:call-template name="error">
+            <xsl:with-param name="m">
+                <xsl:text>unknown algorithm in EncryptionMethod: '</xsl:text>
+                <xsl:value-of select="@Algorithm"/>
+                <xsl:text>'</xsl:text>
+            </xsl:with-param>
+        </xsl:call-template>
+    </xsl:template>
+
+</xsl:stylesheet>
-- 
cgit v1.2.3