xmltooling/encryption/impl/Decrypter.cpp

   1 /*
   2  *  Copyright 2001-2007 Internet2
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 /**
  18  * Decrypter.cpp
  19  *
  20  * Methods for decrypting XMLObjects and other data.
  21  */
  22
  23 #include "internal.h"
  24 #include "logging.h"
  25 #include "encryption/Decrypter.h"
  26 #include "encryption/EncryptedKeyResolver.h"
  27 #include "security/Credential.h"
  28 #include "security/CredentialCriteria.h"
  29 #include "security/CredentialResolver.h"
  30
  31 #include <xsec/enc/XSECCryptoException.hpp>
  32 #include <xsec/framework/XSECException.hpp>
  33 #include <xsec/framework/XSECAlgorithmMapper.hpp>
  34 #include <xsec/framework/XSECAlgorithmHandler.hpp>
  35 #include <xsec/utils/XSECBinTXFMInputStream.hpp>
  36 #include <xsec/xenc/XENCEncryptedData.hpp>
  37 #include <xsec/xenc/XENCEncryptedKey.hpp>
  38
  39 using namespace xmlencryption;
  40 using namespace xmlsignature;
  41 using namespace xmltooling;
  42 using namespace std;
  43
  44 Decrypter::~Decrypter()
  45 {
  46     if (m_cipher)
  47         XMLToolingInternalConfig::getInternalConfig().m_xsecProvider->releaseCipher(m_cipher);
  48 }
  49
  50 DOMDocumentFragment* Decrypter::decryptData(const EncryptedData& encryptedData, XSECCryptoKey* key)
  51 {
  52     if (encryptedData.getDOM()==NULL)
  53         throw DecryptionException("The object must be marshalled before decryption.");
  54
  55     // We can reuse the cipher object if the document hasn't changed.
  56
  57     if (m_cipher && m_cipher->getDocument()!=encryptedData.getDOM()->getOwnerDocument()) {
  58         XMLToolingInternalConfig::getInternalConfig().m_xsecProvider->releaseCipher(m_cipher);
  59         m_cipher=NULL;
  60     }
  61
  62     if (!m_cipher)
  63         m_cipher=XMLToolingInternalConfig::getInternalConfig().m_xsecProvider->newCipher(encryptedData.getDOM()->getOwnerDocument());
  64
  65     try {
  66         m_cipher->setKey(key->clone());
  67         DOMNode* ret=m_cipher->decryptElementDetached(encryptedData.getDOM());
  68         if (ret->getNodeType()!=DOMNode::DOCUMENT_FRAGMENT_NODE) {
  69             ret->release();
  70             throw DecryptionException("Decryption operation did not result in DocumentFragment.");
  71         }
  72         return static_cast<DOMDocumentFragment*>(ret);
  73     }
  74     catch(XSECException& e) {
  75         auto_ptr_char temp(e.getMsg());
  76         throw DecryptionException(string("XMLSecurity exception while decrypting: ") + temp.get());
  77     }
  78     catch(XSECCryptoException& e) {
  79         throw DecryptionException(string("XMLSecurity exception while decrypting: ") + e.getMsg());
  80     }
  81 }
  82
  83 DOMDocumentFragment* Decrypter::decryptData(const EncryptedData& encryptedData, const XMLCh* recipient)
  84 {
  85     if (!m_credResolver)
  86         throw DecryptionException("No CredentialResolver supplied to provide decryption keys.");
  87
  88     // Resolve a decryption key directly.
  89     vector<const Credential*> creds;
  90     int types = CredentialCriteria::KEYINFO_EXTRACTION_KEY | CredentialCriteria::KEYINFO_EXTRACTION_KEYNAMES;
  91     if (m_criteria) {
  92         m_criteria->setUsage(Credential::ENCRYPTION_CREDENTIAL);
  93         m_criteria->setKeyInfo(encryptedData.getKeyInfo(), types);
  94         const EncryptionMethod* meth = encryptedData.getEncryptionMethod();
  95         if (meth)
  96             m_criteria->setXMLAlgorithm(meth->getAlgorithm());
  97         m_credResolver->resolve(creds,m_criteria);
  98     }
  99     else {
 100         CredentialCriteria criteria;
 101         criteria.setUsage(Credential::ENCRYPTION_CREDENTIAL);
 102         criteria.setKeyInfo(encryptedData.getKeyInfo(), types);
 103         const EncryptionMethod* meth = encryptedData.getEncryptionMethod();
 104         if (meth)
 105             criteria.setXMLAlgorithm(meth->getAlgorithm());
 106         m_credResolver->resolve(creds,&criteria);
 107     }
 108
 109     // Loop over them and try each one.
 110     XSECCryptoKey* key;
 111     for (vector<const Credential*>::const_iterator cred = creds.begin(); cred!=creds.end(); ++cred) {
 112         try {
 113             key = (*cred)->getPrivateKey();
 114             if (!key)
 115                 continue;
 116             return decryptData(encryptedData, key);
 117         }
 118         catch(DecryptionException& ex) {
 119             logging::Category::getInstance(XMLTOOLING_LOGCAT".Decrypter").warn(ex.what());
 120         }
 121     }
 122
 123     // We need to find an encrypted decryption key somewhere. We'll need the underlying algorithm...
 124     const XMLCh* algorithm=
 125         encryptedData.getEncryptionMethod() ? encryptedData.getEncryptionMethod()->getAlgorithm() : NULL;
 126     if (!algorithm)
 127         throw DecryptionException("No EncryptionMethod/@Algorithm set, key decryption cannot proceed.");
 128
 129     // Check for external resolver.
 130     const EncryptedKey* encKey=NULL;
 131     if (m_EKResolver)
 132         encKey = m_EKResolver->resolveKey(encryptedData, recipient);
 133     else {
 134         EncryptedKeyResolver ekr;
 135         encKey = ekr.resolveKey(encryptedData, recipient);
 136     }
 137
 138     if (!encKey)
 139         throw DecryptionException("Unable to locate an encrypted key.");
 140
 141     auto_ptr<XSECCryptoKey> keywrapper(decryptKey(*encKey, algorithm));
 142     if (!keywrapper.get())
 143         throw DecryptionException("Unable to decrypt the encrypted key.");
 144     return decryptData(encryptedData, keywrapper.get());
 145 }
 146
 147 void Decrypter::decryptData(ostream& out, const EncryptedData& encryptedData, XSECCryptoKey* key)
 148 {
 149     if (encryptedData.getDOM()==NULL)
 150         throw DecryptionException("The object must be marshalled before decryption.");
 151
 152     // We can reuse the cipher object if the document hasn't changed.
 153
 154     if (m_cipher && m_cipher->getDocument()!=encryptedData.getDOM()->getOwnerDocument()) {
 155         XMLToolingInternalConfig::getInternalConfig().m_xsecProvider->releaseCipher(m_cipher);
 156         m_cipher=NULL;
 157     }
 158
 159     if (!m_cipher)
 160         m_cipher=XMLToolingInternalConfig::getInternalConfig().m_xsecProvider->newCipher(encryptedData.getDOM()->getOwnerDocument());
 161
 162     try {
 163         m_cipher->setKey(key->clone());
 164         auto_ptr<XSECBinTXFMInputStream> in(m_cipher->decryptToBinInputStream(encryptedData.getDOM()));
 165
 166         XMLByte buf[8192];
 167         unsigned int count = in->readBytes(buf, sizeof(buf));
 168         while (count > 0)
 169             out.write(reinterpret_cast<char*>(buf),count);
 170     }
 171     catch(XSECException& e) {
 172         auto_ptr_char temp(e.getMsg());
 173         throw DecryptionException(string("XMLSecurity exception while decrypting: ") + temp.get());
 174     }
 175     catch(XSECCryptoException& e) {
 176         throw DecryptionException(string("XMLSecurity exception while decrypting: ") + e.getMsg());
 177     }
 178 }
 179
 180 void Decrypter::decryptData(ostream& out, const EncryptedData& encryptedData, const XMLCh* recipient)
 181 {
 182     if (!m_credResolver)
 183         throw DecryptionException("No CredentialResolver supplied to provide decryption keys.");
 184
 185     // Resolve a decryption key directly.
 186     vector<const Credential*> creds;
 187     int types = CredentialCriteria::KEYINFO_EXTRACTION_KEY | CredentialCriteria::KEYINFO_EXTRACTION_KEYNAMES;
 188     if (m_criteria) {
 189         m_criteria->setUsage(Credential::ENCRYPTION_CREDENTIAL);
 190         m_criteria->setKeyInfo(encryptedData.getKeyInfo(), types);
 191         const EncryptionMethod* meth = encryptedData.getEncryptionMethod();
 192         if (meth)
 193             m_criteria->setXMLAlgorithm(meth->getAlgorithm());
 194         m_credResolver->resolve(creds,m_criteria);
 195     }
 196     else {
 197         CredentialCriteria criteria;
 198         criteria.setUsage(Credential::ENCRYPTION_CREDENTIAL);
 199         criteria.setKeyInfo(encryptedData.getKeyInfo(), types);
 200         const EncryptionMethod* meth = encryptedData.getEncryptionMethod();
 201         if (meth)
 202             criteria.setXMLAlgorithm(meth->getAlgorithm());
 203         m_credResolver->resolve(creds,&criteria);
 204     }
 205
 206     // Loop over them and try each one.
 207     XSECCryptoKey* key;
 208     for (vector<const Credential*>::const_iterator cred = creds.begin(); cred!=creds.end(); ++cred) {
 209         try {
 210             key = (*cred)->getPrivateKey();
 211             if (!key)
 212                 continue;
 213             return decryptData(out, encryptedData, key);
 214         }
 215         catch(DecryptionException& ex) {
 216             logging::Category::getInstance(XMLTOOLING_LOGCAT".Decrypter").warn(ex.what());
 217         }
 218     }
 219
 220     // We need to find an encrypted decryption key somewhere. We'll need the underlying algorithm...
 221     const XMLCh* algorithm=
 222         encryptedData.getEncryptionMethod() ? encryptedData.getEncryptionMethod()->getAlgorithm() : NULL;
 223     if (!algorithm)
 224         throw DecryptionException("No EncryptionMethod/@Algorithm set, key decryption cannot proceed.");
 225
 226     // Check for external resolver.
 227     const EncryptedKey* encKey=NULL;
 228     if (m_EKResolver)
 229         encKey = m_EKResolver->resolveKey(encryptedData, recipient);
 230     else {
 231         EncryptedKeyResolver ekr;
 232         encKey = ekr.resolveKey(encryptedData, recipient);
 233     }
 234
 235     if (!encKey)
 236         throw DecryptionException("Unable to locate an encrypted key.");
 237
 238     auto_ptr<XSECCryptoKey> keywrapper(decryptKey(*encKey, algorithm));
 239     if (!keywrapper.get())
 240         throw DecryptionException("Unable to decrypt the encrypted key.");
 241     decryptData(out, encryptedData, keywrapper.get());
 242 }
 243
 244 XSECCryptoKey* Decrypter::decryptKey(const EncryptedKey& encryptedKey, const XMLCh* algorithm)
 245 {
 246     if (!m_credResolver)
 247         throw DecryptionException("No CredentialResolver supplied to provide decryption keys.");
 248
 249     if (encryptedKey.getDOM()==NULL)
 250         throw DecryptionException("The object must be marshalled before decryption.");
 251
 252     XSECAlgorithmHandler* handler = XSECPlatformUtils::g_algorithmMapper->mapURIToHandler(algorithm);
 253     if (!handler)
 254         throw DecryptionException("Unrecognized algorithm, no way to build object around decrypted key.");
 255
 256     // We can reuse the cipher object if the document hasn't changed.
 257
 258     if (m_cipher && m_cipher->getDocument()!=encryptedKey.getDOM()->getOwnerDocument()) {
 259         XMLToolingInternalConfig::getInternalConfig().m_xsecProvider->releaseCipher(m_cipher);
 260         m_cipher=NULL;
 261     }
 262
 263     if (!m_cipher)
 264         m_cipher=XMLToolingInternalConfig::getInternalConfig().m_xsecProvider->newCipher(encryptedKey.getDOM()->getOwnerDocument());
 265
 266     // Resolve key decryption keys.
 267     int types = CredentialCriteria::KEYINFO_EXTRACTION_KEY | CredentialCriteria::KEYINFO_EXTRACTION_KEYNAMES;
 268     vector<const Credential*> creds;
 269     if (m_criteria) {
 270         m_criteria->setUsage(Credential::ENCRYPTION_CREDENTIAL);
 271         m_criteria->setKeyInfo(encryptedKey.getKeyInfo(), types);
 272         const EncryptionMethod* meth = encryptedKey.getEncryptionMethod();
 273         if (meth)
 274             m_criteria->setXMLAlgorithm(meth->getAlgorithm());
 275         m_credResolver->resolve(creds, m_criteria);
 276     }
 277     else {
 278         CredentialCriteria criteria;
 279         criteria.setUsage(Credential::ENCRYPTION_CREDENTIAL);
 280         criteria.setKeyInfo(encryptedKey.getKeyInfo(), types);
 281         const EncryptionMethod* meth = encryptedKey.getEncryptionMethod();
 282         if (meth)
 283             criteria.setXMLAlgorithm(meth->getAlgorithm());
 284         m_credResolver->resolve(creds, &criteria);
 285     }
 286     if (creds.empty())
 287         throw DecryptionException("Unable to resolve any key decryption keys.");
 288
 289     XMLByte buffer[1024];
 290     for (vector<const Credential*>::const_iterator cred = creds.begin(); cred!=creds.end(); ++cred) {
 291         try {
 292             if (!(*cred)->getPrivateKey())
 293                 throw DecryptionException("Credential did not contain a private key.");
 294             memset(buffer,0,sizeof(buffer));
 295             m_cipher->setKEK((*cred)->getPrivateKey()->clone());
 296
 297             try {
 298                 int keySize = m_cipher->decryptKey(encryptedKey.getDOM(), buffer, 1024);
 299                 if (keySize<=0)
 300                     throw DecryptionException("Unable to decrypt key.");
 301
 302                 // Try to wrap the key.
 303                 return handler->createKeyForURI(algorithm, buffer, keySize);
 304             }
 305             catch(XSECException& e) {
 306                 auto_ptr_char temp(e.getMsg());
 307                 throw DecryptionException(string("XMLSecurity exception while decrypting key: ") + temp.get());
 308             }
 309             catch(XSECCryptoException& e) {
 310                 throw DecryptionException(string("XMLSecurity exception while decrypting key: ") + e.getMsg());
 311             }
 312         }
 313         catch(DecryptionException& ex) {
 314             logging::Category::getInstance(XMLTOOLING_LOGCAT".Decrypter").warn(ex.what());
 315         }
 316     }
 317
 318     throw DecryptionException("Unable to decrypt key.");
 319 }