XML Key loading tweaks

phpseclib/Crypt/DSA/Formats/Keys/XML.php

@@ -23,6 +23,7 @@ namespace phpseclib3\Crypt\DSA\Formats\Keys;
 
 use ParagonIE\ConstantTime\Base64;
 use phpseclib3\Common\Functions\Strings;
+use phpseclib3\Exception\BadConfigurationException;
 use phpseclib3\Math\BigInteger;
 
 /**
@@ -48,6 +49,10 @@ abstract class XML
             throw new \UnexpectedValueException('Key should be a string - not a ' . gettype($key));
         }
 
+        if (!class_exists('DOMDocument')) {
+            throw new BadConfigurationException('The dom extension is not setup correctly on this system');
+        }
+
         $use_errors = libxml_use_internal_errors(true);
 
         $dom = new \DOMDocument();
@@ -55,6 +60,7 @@ abstract class XML
             $key = '<xml>' . $key . '</xml>';
         }
         if (!$dom->loadXML($key)) {
+            libxml_use_internal_errors($use_errors);
             throw new \UnexpectedValueException('Key does not appear to contain XML');
         }
         $xpath = new \DOMXPath($dom);

phpseclib/Crypt/EC/Formats/Keys/XML.php

@@ -26,6 +26,7 @@ use phpseclib3\Crypt\EC\BaseCurves\Base as BaseCurve;
 use phpseclib3\Crypt\EC\BaseCurves\Montgomery as MontgomeryCurve;
 use phpseclib3\Crypt\EC\BaseCurves\Prime as PrimeCurve;
 use phpseclib3\Crypt\EC\BaseCurves\TwistedEdwards as TwistedEdwardsCurve;
+use phpseclib3\Exception\BadConfigurationException;
 use phpseclib3\Exception\UnsupportedCurveException;
 use phpseclib3\Math\BigInteger;
 
@@ -70,6 +71,10 @@ abstract class XML
             throw new \UnexpectedValueException('Key should be a string - not a ' . gettype($key));
         }
 
+        if (!class_exists('DOMDocument')) {
+            throw new BadConfigurationException('The dom extension is not setup correctly on this system');
+        }
+
         $use_errors = libxml_use_internal_errors(true);
 
         $temp = self::isolateNamespace($key, 'http://www.w3.org/2009/xmldsig11#');

phpseclib/Crypt/RSA/Formats/Keys/XML.php

@@ -24,6 +24,7 @@ namespace phpseclib3\Crypt\RSA\Formats\Keys;
 
 use ParagonIE\ConstantTime\Base64;
 use phpseclib3\Common\Functions\Strings;
+use phpseclib3\Exception\BadConfigurationException;
 use phpseclib3\Exception\UnsupportedFormatException;
 use phpseclib3\Math\BigInteger;
 
@@ -50,6 +51,10 @@ abstract class XML
             throw new \UnexpectedValueException('Key should be a string - not a ' . gettype($key));
         }
 
+        if (!class_exists('DOMDocument')) {
+            throw new BadConfigurationException('The dom extension is not setup correctly on this system');
+        }
+
         $components = [
             'isPublicKey' => false,
             'primes' => [],
@@ -64,6 +69,7 @@ abstract class XML
             $key = '<xml>' . $key . '</xml>';
         }
         if (!$dom->loadXML($key)) {
+            libxml_use_internal_errors($use_errors);
             throw new \UnexpectedValueException('Key does not appear to contain XML');
         }
         $xpath = new \DOMXPath($dom);