XML.php

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<?php
namespace SimpleSAML\Utils;

use SimpleSAML\Logger;
use SimpleSAML\XML\Errors;

class XML
{

    public static function checkSAMLMessage($message, $type)
    {
        $allowed_types = array('saml20', 'saml11', 'saml-meta');
        if (!(is_string($message) && in_array($type, $allowed_types, true))) {
            throw new \InvalidArgumentException('Invalid input parameters.');
        }

        // a SAML message should not contain a doctype-declaration
        if (strpos($message, '<!DOCTYPE') !== false) {
            throw new \SimpleSAML_Error_Exception('XML contained a doctype declaration.');
        }

        // see if debugging is enabled for XML validation
        $debug = \SimpleSAML_Configuration::getInstance()->getArrayize('debug', array('validatexml' => false));
        $enabled = \SimpleSAML_Configuration::getInstance()->getBoolean('debug.validatexml', false);

        if (!(in_array('validatexml', $debug, true) // implicitly enabled
              || (array_key_exists('validatexml', $debug) && $debug['validatexml'] === true) // explicitly enabled
              // TODO: deprecate this option and remove it in 2.0
              || $enabled // old 'debug.validatexml' configuration option
        )) {
            // XML validation is disabled
            return;
        }

        $result = true;
        switch ($type) {
            case 'saml11':
                $result = self::isValid($message, 'oasis-sstc-saml-schema-protocol-1.1.xsd');
                break;
            case 'saml20':
                $result = self::isValid($message, 'saml-schema-protocol-2.0.xsd');
                break;
            case 'saml-meta':
                $result = self::isValid($message, 'saml-schema-metadata-2.0.xsd');
        }
        if ($result !== true) {
            Logger::warning($result);
        }
    }


    public static function debugSAMLMessage($message, $type)
    {
        if (!(is_string($type) && (is_string($message) || $message instanceof \DOMElement))) {
            throw new \InvalidArgumentException('Invalid input parameters.');
        }

        // see if debugging is enabled for SAML messages
        $debug = \SimpleSAML_Configuration::getInstance()->getArrayize('debug', array('saml' => false));

        if (!(in_array('saml', $debug, true) // implicitly enabled
              || (array_key_exists('saml', $debug) && $debug['saml'] === true) // explicitly enabled
              // TODO: deprecate the old style and remove it in 2.0
              || (array_key_exists(0, $debug) && $debug[0] === true) // old style 'debug'
        )) {
            // debugging messages is disabled
            return;
        }

        if ($message instanceof \DOMElement) {
            $message = $message->ownerDocument->saveXML($message);
        }

        switch ($type) {
            case 'in':
                Logger::debug('Received message:');
                break;
            case 'out':
                Logger::debug('Sending message:');
                break;
            case 'decrypt':
                Logger::debug('Decrypted message:');
                break;
            case 'encrypt':
                Logger::debug('Encrypted message:');
                break;
            default:
                assert(false);
        }

        $str = self::formatXMLString($message);
        foreach (explode("\n", $str) as $line) {
            Logger::debug($line);
        }
    }


    public static function formatDOMElement(\DOMNode $root, $indentBase = '')
    {
        if (!is_string($indentBase)) {
            throw new \InvalidArgumentException('Invalid input parameters');
        }

        // check what this element contains
        $fullText = ''; // all text in this element
        $textNodes = array(); // text nodes which should be deleted
        $childNodes = array(); // other child nodes
        for ($i = 0; $i < $root->childNodes->length; $i++) {
            $child = $root->childNodes->item($i);

            if ($child instanceof \DOMText) {
                $textNodes[] = $child;
                $fullText .= $child->wholeText;
            } elseif ($child instanceof \DOMComment || $child instanceof \DOMElement) {
                $childNodes[] = $child;
            } else {
                // unknown node type. We don't know how to format this
                return;
            }
        }

        $fullText = trim($fullText);
        if (strlen($fullText) > 0) {
            // we contain textelf
            $hasText = true;
        } else {
            $hasText = false;
        }

        $hasChildNode = (count($childNodes) > 0);

        if ($hasText && $hasChildNode) {
            // element contains both text and child nodes - we don't know how to format this one
            return;
        }

        // remove text nodes
        foreach ($textNodes as $node) {
            $root->removeChild($node);
        }

        if ($hasText) {
            // only text - add a single text node to the element with the full text
            $root->appendChild(new \DOMText($fullText));
            return;
        }

        if (!$hasChildNode) {
            // empty node. Nothing to do
            return;
        }

        /* Element contains only child nodes - add indentation before each one, and
         * format child elements.
         */
        $childIndentation = $indentBase.'  ';
        foreach ($childNodes as $node) {
            // add indentation before node
            $root->insertBefore(new \DOMText("\n".$childIndentation), $node);

            // format child elements
            if ($node instanceof \DOMElement) {
                self::formatDOMElement($node, $childIndentation);
            }
        }

        // add indentation before closing tag
        $root->appendChild(new \DOMText("\n".$indentBase));
    }


    public static function formatXMLString($xml, $indentBase = '')
    {
        if (!is_string($xml) || !is_string($indentBase)) {
            throw new \InvalidArgumentException('Invalid input parameters');
        }

        try {
            $doc = \SAML2\DOMDocumentFactory::fromString($xml);
        } catch (\Exception $e) {
            throw new \DOMException('Error parsing XML string.');
        }

        $root = $doc->firstChild;
        self::formatDOMElement($root, $indentBase);

        return $doc->saveXML($root);
    }


    public static function getDOMChildren(\DOMNode $element, $localName, $namespaceURI)
    {
        if (!is_string($localName) || !is_string($namespaceURI)) {
            throw new \InvalidArgumentException('Invalid input parameters.');
        }

        $ret = array();

        for ($i = 0; $i < $element->childNodes->length; $i++) {
            $child = $element->childNodes->item($i);

            // skip text nodes and comment elements
            if ($child instanceof \DOMText || $child instanceof \DOMComment) {
                continue;
            }

            if (self::isDOMNodeOfType($child, $localName, $namespaceURI) === true) {
                $ret[] = $child;
            }
        }

        return $ret;
    }


    public static function getDOMText(\DOMElement $element)
    {
        $txt = '';

        for ($i = 0; $i < $element->childNodes->length; $i++) {
            $child = $element->childNodes->item($i);
            if (!($child instanceof \DOMText)) {
                throw new \SimpleSAML_Error_Exception($element->localName.' contained a non-text child node.');
            }

            $txt .= $child->wholeText;
        }

        $txt = trim($txt);
        return $txt;
    }


    public static function isDOMNodeOfType(\DOMNode $element, $name, $nsURI)
    {
        if (!is_string($name) || !is_string($nsURI) || strlen($nsURI) === 0) {
            // most likely a comment-node
            return false;
        }

        // check if the namespace is a shortcut, and expand it if it is
        if ($nsURI[0] === '@') {
            // the defined shortcuts
            $shortcuts = array(
                '@ds'      => 'http://www.w3.org/2000/09/xmldsig#',
                '@md'      => 'urn:oasis:names:tc:SAML:2.0:metadata',
                '@saml1'   => 'urn:oasis:names:tc:SAML:1.0:assertion',
                '@saml1md' => 'urn:oasis:names:tc:SAML:profiles:v1metadata',
                '@saml1p'  => 'urn:oasis:names:tc:SAML:1.0:protocol',
                '@saml2'   => 'urn:oasis:names:tc:SAML:2.0:assertion',
                '@saml2p'  => 'urn:oasis:names:tc:SAML:2.0:protocol',
                '@shibmd'  => 'urn:mace:shibboleth:metadata:1.0',
            );

            // check if it is a valid shortcut
            if (!array_key_exists($nsURI, $shortcuts)) {
                throw new \InvalidArgumentException('Unknown namespace shortcut: '.$nsURI);
            }

            // expand the shortcut
            $nsURI = $shortcuts[$nsURI];
        }
        if ($element->localName !== $name) {
            return false;
        }
        if ($element->namespaceURI !== $nsURI) {
            return false;
        }
        return true;
    }


    public static function isValid($xml, $schema)
    {
        if (!(is_string($schema) && (is_string($xml) || $xml instanceof \DOMDocument))) {
            throw new \InvalidArgumentException('Invalid input parameters.');
        }

        Errors::begin();

        if ($xml instanceof \DOMDocument) {
            $dom = $xml;
            $res = true;
        } else {
            try {
                $dom = \SAML2\DOMDocumentFactory::fromString($xml);
                $res = true;
            } catch (\Exception $e) {
                $res = false;
            }
        }

        if ($res) {
            $config = \SimpleSAML_Configuration::getInstance();
            $schemaPath = $config->resolvePath('schemas');
            $schemaPath .= './';
            $schemaFile = $schemaPath.$schema;

            $res = $dom->schemaValidate($schemaFile);
            if ($res) {
                Errors::end();
                return true;
            }

            $errorText = "Schema validation failed on XML string:\n";
        } else {
            $errorText = "Failed to parse XML string for schema validation:\n";
        }

        $errors = Errors::end();
        $errorText .= Errors::formatErrors($errors);

        return $errorText;
    }
}