public override void LoadInnerXml(XmlNodeList nodeList)
{
if (nodeList == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_UnknownTransform);
}
ExceptUris.Clear();
foreach (XmlNode node in nodeList)
{
XmlElement elem = node as XmlElement;
if (elem != null)
{
if (elem.LocalName == "Except" && elem.NamespaceURI == XmlDecryptionTransformNamespaceUrl)
{
// the Uri is required
string uri = Utils.GetAttribute(elem, "URI", XmlDecryptionTransformNamespaceUrl);
if (uri == null || uri.Length == 0 || uri[0] != '#')
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_UriRequired);
}
if (!Utils.VerifyAttributes(elem, "URI"))
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_UnknownTransform);
}
string idref = Utils.ExtractIdFromLocalUri(uri);
ExceptUris.Add(idref);
}
else
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_UnknownTransform);
}
}
}
}
private int GetReferenceLevel(int index, ArrayList references)
{
if (_refProcessed[index])
{
return(_refLevelCache[index]);
}
_refProcessed[index] = true;
Reference reference = (Reference)references[index];
if (reference.Uri == null || reference.Uri.Length == 0 || (reference.Uri.Length > 0 && reference.Uri[0] != '#'))
{
_refLevelCache[index] = 0;
return(0);
}
if (reference.Uri.Length > 0 && reference.Uri[0] == '#')
{
string idref = Utils.ExtractIdFromLocalUri(reference.Uri);
if (idref == "xpointer(/)")
{
_refLevelCache[index] = 0;
return(0);
}
// If this is pointing to another reference
for (int j = 0; j < references.Count; ++j)
{
if (((Reference)references[j]).Id == idref)
{
_refLevelCache[index] = GetReferenceLevel(j, references) + 1;
return(_refLevelCache[index]);
}
}
// Then the reference points to an object tag
_refLevelCache[index] = 0;
return(0);
}
// Malformed reference
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_InvalidReference);
}
// Try to decrypt the EncryptedKey given the key mapping
public virtual byte[] DecryptEncryptedKey(EncryptedKey encryptedKey, RsaKeyParameters privateKey = null)
{
if (encryptedKey == null)
{
throw new ArgumentNullException(nameof(encryptedKey));
}
if (encryptedKey.KeyInfo == null)
{
return(null);
}
IEnumerator keyInfoEnum = encryptedKey.KeyInfo.GetEnumerator();
KeyInfoName kiName;
KeyInfoX509Data kiX509Data;
KeyInfoRetrievalMethod kiRetrievalMethod;
KeyInfoEncryptedKey kiEncKey;
EncryptedKey ek = null;
bool fOAEP = false;
while (keyInfoEnum.MoveNext())
{
kiName = keyInfoEnum.Current as KeyInfoName;
if (kiName != null)
{
// Get the decryption key from the key mapping
string keyName = kiName.Value;
object kek = _keyNameMapping[keyName];
if (kek != null)
{
if (encryptedKey.CipherData == null || encryptedKey.CipherData.CipherValue == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_MissingAlgorithm);
}
// kek is either a SymmetricAlgorithm or an RSA key, otherwise, we wouldn't be able to insert it in the hash table
if (kek is KeyParameter kp)
{
return(EncryptedXml.DecryptKey(encryptedKey.CipherData.CipherValue, kp));
}
else if (kek is ParametersWithIV piv)
{
return(EncryptedXml.DecryptKey(encryptedKey.CipherData.CipherValue, piv.Parameters as KeyParameter));
}
// kek is an RSA key: get fOAEP from the algorithm, default to false
fOAEP = (encryptedKey.EncryptionMethod != null && encryptedKey.EncryptionMethod.KeyAlgorithm == EncryptedXml.XmlEncRSAOAEPUrl);
return(EncryptedXml.DecryptKey(encryptedKey.CipherData.CipherValue, (RsaKeyParameters)kek, fOAEP));
}
break;
}
kiX509Data = keyInfoEnum.Current as KeyInfoX509Data;
if (kiX509Data != null)
{
IList <X509Certificate> collection = Utils.BuildBagOfCerts(kiX509Data, CertUsageType.Decryption);
foreach (X509Certificate certificate in collection)
{
if (privateKey != null)
{
if (encryptedKey.CipherData == null || encryptedKey.CipherData.CipherValue == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_MissingAlgorithm);
}
fOAEP = (encryptedKey.EncryptionMethod != null && encryptedKey.EncryptionMethod.KeyAlgorithm == EncryptedXml.XmlEncRSAOAEPUrl);
return(EncryptedXml.DecryptKey(encryptedKey.CipherData.CipherValue, privateKey, fOAEP));
}
}
break;
}
kiRetrievalMethod = keyInfoEnum.Current as KeyInfoRetrievalMethod;
if (kiRetrievalMethod != null)
{
string idref = Utils.ExtractIdFromLocalUri(kiRetrievalMethod.Uri);
ek = new EncryptedKey();
ek.LoadXml(GetIdElement(_document, idref));
try
{
//Following checks if XML dsig processing is in loop and within the limit defined by machine
// admin or developer. Once the recursion depth crosses the defined limit it will throw exception.
_xmlDsigSearchDepthCounter++;
if (IsOverXmlDsigRecursionLimit())
{
//Throw exception once recursion limit is hit.
throw new CryptoSignedXmlRecursionException();
}
else
{
return(DecryptEncryptedKey(ek, privateKey));
}
}
finally
{
_xmlDsigSearchDepthCounter--;
}
}
kiEncKey = keyInfoEnum.Current as KeyInfoEncryptedKey;
if (kiEncKey != null)
{
ek = kiEncKey.EncryptedKey;
// recursively process EncryptedKey elements
byte[] encryptionKey = DecryptEncryptedKey(ek, privateKey);
if (encryptionKey != null)
{
// this is a symmetric algorithm for sure
IBlockCipher blockSymAlg = CryptoHelpers.CreateFromName <IBlockCipher>(encryptedKey.EncryptionMethod.KeyAlgorithm);
if (blockSymAlg == null)
{
IBufferedCipher bufferedSymAlg = CryptoHelpers.CreateFromName <IBufferedCipher>(encryptedKey.EncryptionMethod.KeyAlgorithm);
if (bufferedSymAlg == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_MissingAlgorithm);
}
}
if (encryptedKey.CipherData == null || encryptedKey.CipherData.CipherValue == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_MissingAlgorithm);
}
return(EncryptedXml.DecryptKey(encryptedKey.CipherData.CipherValue, new KeyParameter(encryptionKey)));
}
}
}
return(null);
}
// default behaviour is to look for keys defined by an EncryptedKey clause
// either directly or through a KeyInfoRetrievalMethod, and key names in the key mapping
public virtual ICipherParameters GetDecryptionKey(EncryptedData encryptedData, string symmetricAlgorithmUri)
{
if (encryptedData == null)
{
throw new ArgumentNullException(nameof(encryptedData));
}
if (encryptedData.KeyInfo == null)
{
return(null);
}
IEnumerator keyInfoEnum = encryptedData.KeyInfo.GetEnumerator();
KeyInfoRetrievalMethod kiRetrievalMethod;
KeyInfoName kiName;
KeyInfoEncryptedKey kiEncKey;
EncryptedKey ek = null;
while (keyInfoEnum.MoveNext())
{
kiName = keyInfoEnum.Current as KeyInfoName;
if (kiName != null)
{
// Get the decryption key from the key mapping
string keyName = kiName.Value;
if (_keyNameMapping[keyName] as ICipherParameters != null)
{
return((ICipherParameters)_keyNameMapping[keyName]);
}
// try to get it from a CarriedKeyName
XmlNamespaceManager nsm = new XmlNamespaceManager(_document.NameTable);
nsm.AddNamespace("enc", EncryptedXml.XmlEncNamespaceUrl);
XmlNodeList encryptedKeyList = _document.SelectNodes("//enc:EncryptedKey", nsm);
if (encryptedKeyList != null)
{
foreach (XmlNode encryptedKeyNode in encryptedKeyList)
{
XmlElement encryptedKeyElement = encryptedKeyNode as XmlElement;
EncryptedKey ek1 = new EncryptedKey();
ek1.LoadXml(encryptedKeyElement);
if (ek1.CarriedKeyName == keyName && ek1.Recipient == Recipient)
{
ek = ek1;
break;
}
}
}
break;
}
kiRetrievalMethod = keyInfoEnum.Current as KeyInfoRetrievalMethod;
if (kiRetrievalMethod != null)
{
string idref = Utils.ExtractIdFromLocalUri(kiRetrievalMethod.Uri);
ek = new EncryptedKey();
ek.LoadXml(GetIdElement(_document, idref));
break;
}
kiEncKey = keyInfoEnum.Current as KeyInfoEncryptedKey;
if (kiEncKey != null)
{
ek = kiEncKey.EncryptedKey;
break;
}
}
// if we have an EncryptedKey, decrypt to get the symmetric key
if (ek != null)
{
// now process the EncryptedKey, loop recursively
// If the Uri is not provided by the application, try to get it from the EncryptionMethod
if (symmetricAlgorithmUri == null)
{
if (encryptedData.EncryptionMethod == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_MissingAlgorithm);
}
symmetricAlgorithmUri = encryptedData.EncryptionMethod.KeyAlgorithm;
}
byte[] key = DecryptEncryptedKey(ek);
if (key == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_MissingDecryptionKey);
}
IBufferedCipher symAlg = CryptoHelpers.CreateFromName <IBufferedCipher>(symmetricAlgorithmUri);
if (symAlg == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_MissingAlgorithm);
}
KeyParameter keyParam;
if (symAlg.AlgorithmName.IndexOf("DESede", StringComparison.OrdinalIgnoreCase) >= 0)
{
keyParam = new DesEdeParameters(key);
}
else if (symAlg.AlgorithmName.IndexOf("DES", StringComparison.OrdinalIgnoreCase) >= 0)
{
keyParam = new DesParameters(key);
}
else
{
keyParam = new KeyParameter(key);
}
return(keyParam);
}
return(null);
}
//
// private methods
//
private byte[] GetCipherValue(CipherData cipherData)
{
if (cipherData == null)
{
throw new ArgumentNullException(nameof(cipherData));
}
Stream inputStream = null;
if (cipherData.CipherValue != null)
{
return(cipherData.CipherValue);
}
else if (cipherData.CipherReference != null)
{
if (cipherData.CipherReference.CipherValue != null)
{
return(cipherData.CipherReference.CipherValue);
}
Stream decInputStream = null;
if (cipherData.CipherReference.Uri == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_UriNotSupported);
}
// See if the CipherReference is a local URI
if (cipherData.CipherReference.Uri.Length == 0)
{
// self referenced Uri
string baseUri = (_document == null ? null : _document.BaseURI);
TransformChain tc = cipherData.CipherReference.TransformChain;
if (tc == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_UriNotSupported);
}
decInputStream = tc.TransformToOctetStream(_document, _xmlResolver, baseUri);
}
else if (cipherData.CipherReference.Uri[0] == '#')
{
string idref = Utils.ExtractIdFromLocalUri(cipherData.CipherReference.Uri);
// Serialize
XmlElement idElem = GetIdElement(_document, idref);
if (idElem == null || idElem.OuterXml == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_UriNotSupported);
}
inputStream = new MemoryStream(_encoding.GetBytes(idElem.OuterXml));
string baseUri = (_document == null ? null : _document.BaseURI);
TransformChain tc = cipherData.CipherReference.TransformChain;
if (tc == null)
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_UriNotSupported);
}
decInputStream = tc.TransformToOctetStream(inputStream, _xmlResolver, baseUri);
}
else
{
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_UriNotResolved, cipherData.CipherReference.Uri);
}
// read the output stream into a memory stream
byte[] cipherValue = null;
using (MemoryStream ms = new MemoryStream())
{
Utils.Pump(decInputStream, ms);
cipherValue = ms.ToArray();
// Close the stream and return
if (inputStream != null)
{
inputStream.Close();
}
decInputStream.Close();
}
// cache the cipher value for Perf reasons in case we call this routine twice
cipherData.CipherReference.CipherValue = cipherValue;
return(cipherValue);
}
// Throw a CryptographicException if we were unable to retrieve the cipher data.
throw new System.Security.Cryptography.CryptographicException(SR.Cryptography_Xml_MissingCipherData);
}
// default behaviour is to look for keys defined by an EncryptedKey clause
// either directly or through a KeyInfoRetrievalMethod, and key names in the key mapping
public virtual SymmetricAlgorithm GetDecryptionKey(EncryptedData encryptedData, string symmetricAlgorithmUri)
{
if (encryptedData == null)
{
throw new ArgumentNullException("encryptedData");
}
if (encryptedData.KeyInfo == null)
{
return(null);
}
IEnumerator keyInfoEnum = encryptedData.KeyInfo.GetEnumerator();
KeyInfoRetrievalMethod kiRetrievalMethod;
KeyInfoName kiName;
KeyInfoEncryptedKey kiEncKey;
EncryptedKey ek = null;
while (keyInfoEnum.MoveNext())
{
kiName = keyInfoEnum.Current as KeyInfoName;
if (kiName != null)
{
// Get the decryption key from the key mapping
string keyName = kiName.Value;
if ((SymmetricAlgorithm)_keyNameMapping[keyName] != null)
{
return((SymmetricAlgorithm)_keyNameMapping[keyName]);
}
// try to get it from a CarriedKeyName
XmlNamespaceManager nsm = new XmlNamespaceManager(_document.NameTable);
nsm.AddNamespace("enc", EncryptedXml.XmlEncNamespaceUrl);
XmlNodeList encryptedKeyList = _document.SelectNodes("//enc:EncryptedKey", nsm);
if (encryptedKeyList != null)
{
foreach (XmlNode encryptedKeyNode in encryptedKeyList)
{
XmlElement encryptedKeyElement = encryptedKeyNode as XmlElement;
EncryptedKey ek1 = new EncryptedKey();
ek1.LoadXml(encryptedKeyElement);
if (ek1.CarriedKeyName == keyName && ek1.Recipient == Recipient)
{
ek = ek1;
break;
}
}
}
break;
}
kiRetrievalMethod = keyInfoEnum.Current as KeyInfoRetrievalMethod;
if (kiRetrievalMethod != null)
{
string idref = Utils.ExtractIdFromLocalUri(kiRetrievalMethod.Uri);
ek = new EncryptedKey();
ek.LoadXml(GetIdElement(_document, idref));
break;
}
kiEncKey = keyInfoEnum.Current as KeyInfoEncryptedKey;
if (kiEncKey != null)
{
ek = kiEncKey.EncryptedKey;
break;
}
}
// if we have an EncryptedKey, decrypt to get the symmetric key
if (ek != null)
{
// now process the EncryptedKey, loop recursively
// If the Uri is not provided by the application, try to get it from the EncryptionMethod
if (symmetricAlgorithmUri == null)
{
if (encryptedData.EncryptionMethod == null)
{
throw new CryptographicException(SR.Cryptography_Xml_MissingAlgorithm);
}
symmetricAlgorithmUri = encryptedData.EncryptionMethod.KeyAlgorithm;
}
byte[] key = DecryptEncryptedKey(ek);
if (key == null)
{
throw new CryptographicException(SR.Cryptography_Xml_MissingDecryptionKey);
}
SymmetricAlgorithm symAlg = (SymmetricAlgorithm)CryptoHelpers.CreateFromName(symmetricAlgorithmUri);
symAlg.Key = key;
return(symAlg);
}
return(null);
}
