saml/saml2/metadata/impl/SignatureMetadataFilter.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  * SignatureMetadataFilter.cpp
  19  *
  20  * Filters out unsigned or mis-signed elements.
  21  */
  22
  23 #include "internal.h"
  24 #include "saml2/metadata/Metadata.h"
  25 #include "saml2/metadata/MetadataFilter.h"
  26 #include "signature/SignatureProfileValidator.h"
  27
  28 #include <xmltooling/logging.h>
  29 #include <xmltooling/security/Credential.h>
  30 #include <xmltooling/security/CredentialCriteria.h>
  31 #include <xmltooling/security/CredentialResolver.h>
  32 #include <xmltooling/security/SignatureTrustEngine.h>
  33 #include <xmltooling/signature/SignatureValidator.h>
  34 #include <xmltooling/util/NDC.h>
  35
  36 using namespace opensaml::saml2md;
  37 using namespace opensaml;
  38 using namespace xmlsignature;
  39 using namespace xmltooling::logging;
  40 using namespace xmltooling;
  41 using namespace std;
  42
  43 namespace opensaml {
  44     namespace saml2md {
  45
  46         class SAML_DLLLOCAL DummyCredentialResolver : public CredentialResolver
  47         {
  48         public:
  49             DummyCredentialResolver() {}
  50             ~DummyCredentialResolver() {}
  51
  52             Lockable* lock() {return this;}
  53             void unlock() {}
  54
  55             const Credential* resolve(const CredentialCriteria* criteria=NULL) const {return NULL;}
  56             vector<const Credential*>::size_type resolve(
  57                 vector<const Credential*>& results, const CredentialCriteria* criteria=NULL
  58                 ) const {return 0;}
  59         };
  60
  61         class SAML_DLLLOCAL SignatureMetadataFilter : public MetadataFilter
  62         {
  63         public:
  64             SignatureMetadataFilter(const DOMElement* e);
  65             ~SignatureMetadataFilter() {
  66                 delete m_credResolver;
  67             }
  68
  69             const char* getId() const { return SIGNATURE_METADATA_FILTER; }
  70             void doFilter(XMLObject& xmlObject) const;
  71
  72         private:
  73             void doFilter(EntitiesDescriptor& entities, bool rootObject=false) const;
  74             void verifySignature(Signature* sig, const XMLCh* peerName) const;
  75
  76             CredentialResolver* m_credResolver;
  77             SignatureTrustEngine* m_trust;
  78             SignatureProfileValidator m_profileValidator;
  79         };
  80
  81         MetadataFilter* SAML_DLLLOCAL SignatureMetadataFilterFactory(const DOMElement* const & e)
  82         {
  83             return new SignatureMetadataFilter(e);
  84         }
  85
  86     };
  87 };
  88
  89 static const XMLCh _TrustEngine[] =         UNICODE_LITERAL_11(T,r,u,s,t,E,n,g,i,n,e);
  90 static const XMLCh _CredentialResolver[] =  UNICODE_LITERAL_18(C,r,e,d,e,n,t,i,a,l,R,e,s,o,l,v,e,r);
  91 static const XMLCh type[] =                 UNICODE_LITERAL_4(t,y,p,e);
  92 static const XMLCh certificate[] =          UNICODE_LITERAL_11(c,e,r,t,i,f,i,c,a,t,e);
  93 static const XMLCh Certificate[] =          UNICODE_LITERAL_11(C,e,r,t,i,f,i,c,a,t,e);
  94 static const XMLCh Path[] =                 UNICODE_LITERAL_4(P,a,t,h);
  95
  96 SignatureMetadataFilter::SignatureMetadataFilter(const DOMElement* e) : m_credResolver(NULL), m_trust(NULL)
  97 {
  98     if (e && e->hasAttributeNS(NULL,certificate)) {
  99         // Dummy up a file resolver.
 100         DOMElement* dummy = e->getOwnerDocument()->createElementNS(NULL,_CredentialResolver);
 101         DOMElement* child = e->getOwnerDocument()->createElementNS(NULL,Certificate);
 102         dummy->appendChild(child);
 103         DOMElement* path = e->getOwnerDocument()->createElementNS(NULL,Path);
 104         child->appendChild(path);
 105         path->appendChild(e->getOwnerDocument()->createTextNode(e->getAttributeNS(NULL,certificate)));
 106         m_credResolver = XMLToolingConfig::getConfig().CredentialResolverManager.newPlugin(FILESYSTEM_CREDENTIAL_RESOLVER,dummy);
 107         return;
 108     }
 109
 110     DOMElement* sub = e ? XMLHelper::getFirstChildElement(e, _CredentialResolver) : NULL;
 111     auto_ptr_char t(sub ? sub->getAttributeNS(NULL,type) : NULL);
 112     if (t.get()) {
 113         m_credResolver = XMLToolingConfig::getConfig().CredentialResolverManager.newPlugin(t.get(),sub);
 114         return;
 115     }
 116
 117     sub = e ? XMLHelper::getFirstChildElement(e, _TrustEngine) : NULL;
 118     auto_ptr_char t2(sub ? sub->getAttributeNS(NULL,type) : NULL);
 119     if (t2.get()) {
 120         TrustEngine* trust = XMLToolingConfig::getConfig().TrustEngineManager.newPlugin(t2.get(),sub);
 121         if (!(m_trust = dynamic_cast<SignatureTrustEngine*>(trust))) {
 122             delete trust;
 123             throw MetadataFilterException("TrustEngine-based SignatureMetadataFilter requires a SignatureTrustEngine plugin.");
 124         }
 125         return;
 126     }
 127
 128     throw MetadataFilterException("SignatureMetadataFilter configuration requires <CredentialResolver> or <TrustEngine> element.");
 129 }
 130
 131 void SignatureMetadataFilter::doFilter(XMLObject& xmlObject) const
 132 {
 133 #ifdef _DEBUG
 134     NDC ndc("doFilter");
 135 #endif
 136
 137     try {
 138         EntitiesDescriptor& entities = dynamic_cast<EntitiesDescriptor&>(xmlObject);
 139         doFilter(entities, true);
 140         return;
 141     }
 142     catch (bad_cast) {
 143     }
 144
 145     try {
 146         EntityDescriptor& entity = dynamic_cast<EntityDescriptor&>(xmlObject);
 147         if (!entity.getSignature())
 148             throw MetadataFilterException("Root metadata element was unsigned.");
 149         verifySignature(entity.getSignature(), entity.getEntityID());
 150     }
 151     catch (bad_cast) {
 152     }
 153
 154     throw MetadataFilterException("SignatureMetadataFilter was given an improper metadata instance to filter.");
 155 }
 156
 157 void SignatureMetadataFilter::doFilter(EntitiesDescriptor& entities, bool rootObject) const
 158 {
 159     Category& log=Category::getInstance(SAML_LOGCAT".MetadataFilter.Signature");
 160
 161     Signature* sig = entities.getSignature();
 162     if (!sig && rootObject)
 163         throw MetadataFilterException("Root metadata element was unsigned.");
 164     verifySignature(sig, entities.getName());
 165
 166     VectorOf(EntityDescriptor) v=entities.getEntityDescriptors();
 167     for (VectorOf(EntityDescriptor)::size_type i=0; i<v.size(); ) {
 168         try {
 169             verifySignature(v[i]->getSignature(), v[i]->getEntityID());
 170             i++;
 171         }
 172         catch (exception& e) {
 173             auto_ptr_char id(v[i]->getEntityID());
 174             log.info("filtering out entity (%s) after failed signature check: ", id.get(), e.what());
 175             v.erase(v.begin() + i);
 176         }
 177     }
 178
 179     VectorOf(EntitiesDescriptor) w=entities.getEntitiesDescriptors();
 180     for (VectorOf(EntitiesDescriptor)::size_type j=0; j<w.size(); ) {
 181         try {
 182             verifySignature(w[j]->getSignature(), w[j]->getName());
 183             j++;
 184         }
 185         catch (exception& e) {
 186             auto_ptr_char name(w[j]->getName());
 187             log.info("filtering out group (%s) after failed signature check: ", name.get(), e.what());
 188             w.erase(w.begin() + j);
 189         }
 190     }
 191 }
 192
 193 void SignatureMetadataFilter::verifySignature(Signature* sig, const XMLCh* peerName) const
 194 {
 195     if (!sig)
 196         return;
 197
 198     m_profileValidator.validate(sig);
 199
 200     // Set up criteria.
 201     CredentialCriteria cc;
 202     cc.setUsage(CredentialCriteria::SIGNING_CREDENTIAL);
 203     cc.setSignature(*sig, CredentialCriteria::KEYINFO_EXTRACTION_KEY);
 204     if (peerName) {
 205         auto_ptr_char pname(peerName);
 206         cc.setPeerName(pname.get());
 207     }
 208
 209     if (m_credResolver) {
 210         Locker locker(m_credResolver);
 211         vector<const Credential*> creds;
 212         if (m_credResolver->resolve(creds,&cc)) {
 213             SignatureValidator sigValidator;
 214             for (vector<const Credential*>::const_iterator i = creds.begin(); i != creds.end(); ++i) {
 215                 try {
 216                     sigValidator.setCredential(*i);
 217                     sigValidator.validate(sig);
 218                     return; // success!
 219                 }
 220                 catch (exception&) {
 221                 }
 222             }
 223             throw MetadataFilterException("CredentialResolver did not supply a successful verification key.");
 224         }
 225         else {
 226             throw MetadataFilterException("CredentialResolver did not supply any verification keys.");
 227         }
 228     }
 229     else if (m_trust) {
 230         DummyCredentialResolver dummy;
 231         if (m_trust->validate(*sig, dummy, &cc))
 232             return;
 233         throw MetadataFilterException("TrustEngine unable to verify signature.");
 234     }
 235
 236     throw MetadataFilterException("Unable to verify signature.");
 237 }