saml/saml2/core/impl/Assertions.cpp

   1 /*
   2  *  Copyright 2001-2009 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
  38 #include <xsec/utils/XSECPlatformUtils.hpp>
  39
  40 using namespace opensaml::saml2md;
  41 using namespace opensaml::saml2;
  42 using namespace xmlencryption;
  43 using namespace xmlsignature;
  44 using namespace xmltooling;
  45 using namespace std;
  46
  47 void EncryptedElementType::encrypt(
  48     const EncryptableObject& xmlObject,
  49     const MetadataProvider& metadataProvider,
  50     MetadataCredentialCriteria& criteria,
  51     bool compact,
  52     const XMLCh* algorithm
  53     )
  54 {
  55     // With one recipient, we let the library generate the encryption key for us.
  56     // Get the key encryption key to use.
  57     criteria.setUsage(Credential::ENCRYPTION_CREDENTIAL);
  58     const Credential* KEK = metadataProvider.resolve(&criteria);
  59     if (!KEK)
  60         throw EncryptionException("No key encryption credential found.");
  61
  62     // Try and find EncryptionMethod information surrounding the credential.
  63     const MetadataCredentialContext* metaCtx = dynamic_cast<const MetadataCredentialContext*>(KEK->getCredentalContext());
  64     if (metaCtx) {
  65         const vector<EncryptionMethod*> encMethods = metaCtx->getKeyDescriptor().getEncryptionMethods();
  66         if (!encMethods.empty())
  67             algorithm = encMethods.front()->getAlgorithm();
  68     }
  69
  70     if (!algorithm || !*algorithm)
  71         algorithm = DSIGConstants::s_unicodeStrURIAES256_CBC;
  72
  73     Encrypter encrypter;
  74     Encrypter::EncryptionParams ep(algorithm, NULL, 0, NULL, compact);
  75     Encrypter::KeyEncryptionParams kep(*KEK);
  76     setEncryptedData(encrypter.encryptElement(xmlObject.getDOM(),ep,&kep));
  77 }
  78
  79 void EncryptedElementType::encrypt(
  80     const EncryptableObject& xmlObject,
  81     const vector< pair<const MetadataProvider*, MetadataCredentialCriteria*> >& recipients,
  82     bool compact,
  83     const XMLCh* algorithm
  84     )
  85 {
  86     // With multiple recipients, we have to generate an encryption key and then multicast it,
  87     // so we need to split the encryption and key wrapping steps.
  88     if (!algorithm || !*algorithm)
  89         algorithm = DSIGConstants::s_unicodeStrURIAES256_CBC;
  90
  91     // Generate a random key.
  92     unsigned char keyBuffer[32];
  93     if (XSECPlatformUtils::g_cryptoProvider->getRandom(keyBuffer,32)<32)
  94         throw EncryptionException("Unable to generate encryption key; was PRNG seeded?");
  95     Encrypter encrypter;
  96     Encrypter::EncryptionParams ep(algorithm, keyBuffer, 32, NULL, compact);
  97     setEncryptedData(encrypter.encryptElement(xmlObject.getDOM(),ep));
  98     getEncryptedData()->setId(SAMLConfig::getConfig().generateIdentifier());
  99
 100     // Generate a uniquely named KeyInfo.
 101     KeyInfo* keyInfo = KeyInfoBuilder::buildKeyInfo();
 102     getEncryptedData()->setKeyInfo(keyInfo);
 103     KeyName* carriedName = KeyNameBuilder::buildKeyName();
 104     keyInfo->getKeyNames().push_back(carriedName);
 105     carriedName->setName(SAMLConfig::getConfig().generateIdentifier());
 106
 107     VectorOf(EncryptedKey) keys = getEncryptedKeys();
 108
 109     // Now we encrypt the key for each recipient.
 110     for (vector< pair<const MetadataProvider*, MetadataCredentialCriteria*> >::const_iterator r = recipients.begin(); r!=recipients.end(); ++r) {
 111         // Get key encryption key to use.
 112         r->second->setUsage(Credential::ENCRYPTION_CREDENTIAL);
 113         const Credential* KEK = r->first->resolve(r->second);
 114         if (!KEK) {
 115             auto_ptr_char name(dynamic_cast<const EntityDescriptor*>(r->second->getRole().getParent())->getEntityID());
 116             logging::Category::getInstance(SAML_LOGCAT".Encryption").warn("No key encryption credential found for (%s).", name.get());
 117             continue;
 118         }
 119
 120         // Encrypt the key and add it to the message.
 121         Encrypter::KeyEncryptionParams kep(
 122             *KEK, Encrypter::getKeyTransportAlgorithm(*KEK, algorithm),
 123             dynamic_cast<const EntityDescriptor*>(r->second->getRole().getParent())->getEntityID()
 124             );
 125         EncryptedKey* encryptedKey = encrypter.encryptKey(keyBuffer, ep.m_keyBufferSize, kep, compact);
 126         keys.push_back(encryptedKey);
 127         if (keys.size()>1) {
 128             // Copy details from the other key.
 129             encryptedKey->setCarriedKeyName(keys.front()->getCarriedKeyName()->cloneCarriedKeyName());
 130             encryptedKey->setReferenceList(keys.front()->getReferenceList()->cloneReferenceList());
 131         }
 132         else {
 133             // Attach the carried key name.
 134             CarriedKeyName* carried = CarriedKeyNameBuilder::buildCarriedKeyName();
 135             carried->setName(carriedName->getName());
 136             encryptedKey->setCarriedKeyName(carried);
 137
 138             // Attach a back-reference to the data.
 139             ReferenceList* reflist = ReferenceListBuilder::buildReferenceList();
 140             encryptedKey->setReferenceList(reflist);
 141             DataReference* dataref = DataReferenceBuilder::buildDataReference();
 142             reflist->getDataReferences().push_back(dataref);
 143             XMLCh* uri = new XMLCh[XMLString::stringLen(getEncryptedData()->getId()) + 2];
 144             *uri = chPound;
 145             *(uri+1) = chNull;
 146             XMLString::catString(uri, getEncryptedData()->getId());
 147             dataref->setURI(uri);
 148             delete[] uri;
 149         }
 150     }
 151 }
 152
 153 XMLObject* EncryptedElementType::decrypt(const CredentialResolver& credResolver, const XMLCh* recipient, CredentialCriteria* criteria) const
 154 {
 155     if (!getEncryptedData())
 156         throw DecryptionException("No encrypted data present.");
 157     EncryptedKeyResolver ekr(*this);
 158     Decrypter decrypter(&credResolver, criteria, &ekr);
 159     DOMDocumentFragment* frag = decrypter.decryptData(*getEncryptedData(), recipient);
 160     if (frag->hasChildNodes() && frag->getFirstChild()==frag->getLastChild()) {
 161         DOMNode* plaintext=frag->getFirstChild();
 162         if (plaintext->getNodeType()==DOMNode::ELEMENT_NODE) {
 163             // Import the tree into a new Document that we can bind to the unmarshalled object.
 164             XercesJanitor<DOMDocument> newdoc(XMLToolingConfig::getConfig().getParser().newDocument());
 165             DOMElement* treecopy = static_cast<DOMElement*>(newdoc->importNode(plaintext, true));
 166             newdoc->appendChild(treecopy);
 167             auto_ptr<XMLObject> ret(XMLObjectBuilder::buildOneFromElement(treecopy, true));
 168             newdoc.release();
 169             return ret.release();
 170         }
 171     }
 172     frag->release();
 173     throw DecryptionException("Decryption did not result in a single element.");
 174 }