saml/saml2/core/impl/Assertions.cpp

   1 /*
   2  *  Copyright 2001-2010 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  * Assertions.cpp
  19  *
  20  * Built-in behavior for SAML 2.0 Assertion interfaces.
  21  */
  22
  23 #include "internal.h"
  24 #include "exceptions.h"
  25 #include "saml/encryption/EncryptedKeyResolver.h"
  26 #include "saml2/core/Assertions.h"
  27 #include "saml2/metadata/Metadata.h"
  28 #include "saml2/metadata/MetadataProvider.h"
  29 #include "saml2/metadata/MetadataCredentialContext.h"
  30 #include "saml2/metadata/MetadataCredentialCriteria.h"
  31
  32 #include <xmltooling/logging.h>
  33 #include <xmltooling/XMLToolingConfig.h>
  34 #include <xmltooling/encryption/Encrypter.h>
  35 #include <xmltooling/encryption/Decrypter.h>
  36 #include <xmltooling/security/Credential.h>
  37 #include <xmltooling/signature/KeyInfo.h>
  38 #include <xmltooling/util/ParserPool.h>
  39
  40 #include <xsec/utils/XSECPlatformUtils.hpp>
  41
  42 using namespace opensaml::saml2md;
  43 using namespace opensaml::saml2;
  44 using namespace xmlencryption;
  45 using namespace xmlsignature;
  46 using namespace xmltooling;
  47 using namespace std;
  48
  49 void EncryptedElementType::encrypt(
  50     const EncryptableObject& xmlObject,
  51     const MetadataProvider& metadataProvider,
  52     MetadataCredentialCriteria& criteria,
  53     bool compact,
  54     const XMLCh* algorithm
  55     )
  56 {
  57     // With one recipient, we let the library generate the encryption key for us.
  58     // Get the key encryption key to use.
  59     criteria.setUsage(Credential::ENCRYPTION_CREDENTIAL);
  60     const Credential* KEK = metadataProvider.resolve(&criteria);
  61     if (!KEK)
  62         throw EncryptionException("No key encryption credential found.");
  63
  64     // Try and find EncryptionMethod information surrounding the credential.
  65     const MetadataCredentialContext* metaCtx = dynamic_cast<const MetadataCredentialContext*>(KEK->getCredentalContext());
  66     if (metaCtx) {
  67         const vector<EncryptionMethod*> encMethods = metaCtx->getKeyDescriptor().getEncryptionMethods();
  68         if (!encMethods.empty())
  69             algorithm = encMethods.front()->getAlgorithm();
  70     }
  71
  72     if (!algorithm || !*algorithm)
  73         algorithm = DSIGConstants::s_unicodeStrURIAES256_CBC;
  74
  75     Encrypter encrypter;
  76     Encrypter::EncryptionParams ep(algorithm, NULL, 0, NULL, compact);
  77     Encrypter::KeyEncryptionParams kep(*KEK);
  78     setEncryptedData(encrypter.encryptElement(xmlObject.getDOM(),ep,&kep));
  79 }
  80
  81 void EncryptedElementType::encrypt(
  82     const EncryptableObject& xmlObject,
  83     const vector< pair<const MetadataProvider*, MetadataCredentialCriteria*> >& recipients,
  84     bool compact,
  85     const XMLCh* algorithm
  86     )
  87 {
  88     // With multiple recipients, we have to generate an encryption key and then multicast it,
  89     // so we need to split the encryption and key wrapping steps.
  90     if (!algorithm || !*algorithm)
  91         algorithm = DSIGConstants::s_unicodeStrURIAES256_CBC;
  92
  93     // Generate a random key.
  94     unsigned char keyBuffer[32];
  95     if (XSECPlatformUtils::g_cryptoProvider->getRandom(keyBuffer,32)<32)
  96         throw EncryptionException("Unable to generate encryption key; was PRNG seeded?");
  97     Encrypter encrypter;
  98     Encrypter::EncryptionParams ep(algorithm, keyBuffer, 32, NULL, compact);
  99     setEncryptedData(encrypter.encryptElement(xmlObject.getDOM(),ep));
 100     getEncryptedData()->setId(SAMLConfig::getConfig().generateIdentifier());
 101
 102     // Generate a uniquely named KeyInfo.
 103     KeyInfo* keyInfo = KeyInfoBuilder::buildKeyInfo();
 104     getEncryptedData()->setKeyInfo(keyInfo);
 105     KeyName* carriedName = KeyNameBuilder::buildKeyName();
 106     keyInfo->getKeyNames().push_back(carriedName);
 107     carriedName->setName(SAMLConfig::getConfig().generateIdentifier());
 108
 109     VectorOf(EncryptedKey) keys = getEncryptedKeys();
 110
 111     // Now we encrypt the key for each recipient.
 112     for (vector< pair<const MetadataProvider*, MetadataCredentialCriteria*> >::const_iterator r = recipients.begin(); r!=recipients.end(); ++r) {
 113         // Get key encryption key to use.
 114         r->second->setUsage(Credential::ENCRYPTION_CREDENTIAL);
 115         const Credential* KEK = r->first->resolve(r->second);
 116         if (!KEK) {
 117             auto_ptr_char name(dynamic_cast<const EntityDescriptor*>(r->second->getRole().getParent())->getEntityID());
 118             logging::Category::getInstance(SAML_LOGCAT".Encryption").warn("No key encryption credential found for (%s).", name.get());
 119             continue;
 120         }
 121
 122         // Encrypt the key and add it to the message.
 123         Encrypter::KeyEncryptionParams kep(
 124             *KEK, Encrypter::getKeyTransportAlgorithm(*KEK, algorithm),
 125             dynamic_cast<const EntityDescriptor*>(r->second->getRole().getParent())->getEntityID()
 126             );
 127         EncryptedKey* encryptedKey = encrypter.encryptKey(keyBuffer, ep.m_keyBufferSize, kep, compact);
 128         keys.push_back(encryptedKey);
 129         if (keys.size()>1) {
 130             // Copy details from the other key.
 131             encryptedKey->setCarriedKeyName(keys.front()->getCarriedKeyName()->cloneCarriedKeyName());
 132             encryptedKey->setReferenceList(keys.front()->getReferenceList()->cloneReferenceList());
 133         }
 134         else {
 135             // Attach the carried key name.
 136             CarriedKeyName* carried = CarriedKeyNameBuilder::buildCarriedKeyName();
 137             carried->setName(carriedName->getName());
 138             encryptedKey->setCarriedKeyName(carried);
 139
 140             // Attach a back-reference to the data.
 141             ReferenceList* reflist = ReferenceListBuilder::buildReferenceList();
 142             encryptedKey->setReferenceList(reflist);
 143             DataReference* dataref = DataReferenceBuilder::buildDataReference();
 144             reflist->getDataReferences().push_back(dataref);
 145             XMLCh* uri = new XMLCh[XMLString::stringLen(getEncryptedData()->getId()) + 2];
 146             *uri = chPound;
 147             *(uri+1) = chNull;
 148             XMLString::catString(uri, getEncryptedData()->getId());
 149             dataref->setURI(uri);
 150             delete[] uri;
 151         }
 152     }
 153 }
 154
 155 XMLObject* EncryptedElementType::decrypt(const CredentialResolver& credResolver, const XMLCh* recipient, CredentialCriteria* criteria) const
 156 {
 157     if (!getEncryptedData())
 158         throw DecryptionException("No encrypted data present.");
 159     EncryptedKeyResolver ekr(*this);
 160     Decrypter decrypter(&credResolver, criteria, &ekr);
 161     DOMDocumentFragment* frag = decrypter.decryptData(*getEncryptedData(), recipient);
 162     if (frag->hasChildNodes() && frag->getFirstChild()==frag->getLastChild()) {
 163         DOMNode* plaintext=frag->getFirstChild();
 164         if (plaintext->getNodeType()==DOMNode::ELEMENT_NODE) {
 165             // Import the tree into a new Document that we can bind to the unmarshalled object.
 166             XercesJanitor<DOMDocument> newdoc(XMLToolingConfig::getConfig().getParser().newDocument());
 167             DOMElement* treecopy;
 168             try {
 169                 treecopy = static_cast<DOMElement*>(newdoc->importNode(plaintext, true));
 170             }
 171             catch (XMLException& ex) {
 172                 frag->release();
 173                 auto_ptr_char temp(ex.getMessage());
 174                 throw DecryptionException(
 175                     string("Error importing decypted DOM into new document: ") + (temp.get() ? temp.get() : "no message")
 176                     );
 177             }
 178             frag->release();
 179             newdoc->appendChild(treecopy);
 180             auto_ptr<XMLObject> ret(XMLObjectBuilder::buildOneFromElement(treecopy, true));
 181             newdoc.release();
 182             return ret.release();
 183         }
 184     }
 185     frag->release();
 186     throw DecryptionException("Decryption did not result in a single element.");
 187 }