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