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             Category& m_log;
  80         };
  81
  82         MetadataFilter* SAML_DLLLOCAL SignatureMetadataFilterFactory(const DOMElement* const & e)
  83         {
  84             return new SignatureMetadataFilter(e);
  85         }
  86
  87     };
  88 };
  89
  90 static const XMLCh _TrustEngine[] =         UNICODE_LITERAL_11(T,r,u,s,t,E,n,g,i,n,e);
  91 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);
  92 static const XMLCh type[] =                 UNICODE_LITERAL_4(t,y,p,e);
  93 static const XMLCh certificate[] =          UNICODE_LITERAL_11(c,e,r,t,i,f,i,c,a,t,e);
  94 static const XMLCh Certificate[] =          UNICODE_LITERAL_11(C,e,r,t,i,f,i,c,a,t,e);
  95 static const XMLCh Path[] =                 UNICODE_LITERAL_4(P,a,t,h);
  96
  97 SignatureMetadataFilter::SignatureMetadataFilter(const DOMElement* e)
  98     : m_credResolver(NULL), m_trust(NULL), m_log(Category::getInstance(SAML_LOGCAT".MetadataFilter.Signature"))
  99 {
 100     if (e && e->hasAttributeNS(NULL,certificate)) {
 101         // Use a file-based credential resolver rooted here.
 102         m_credResolver = XMLToolingConfig::getConfig().CredentialResolverManager.newPlugin(FILESYSTEM_CREDENTIAL_RESOLVER,e);
 103         return;
 104     }
 105
 106     DOMElement* sub = e ? XMLHelper::getFirstChildElement(e, _CredentialResolver) : NULL;
 107     auto_ptr_char t(sub ? sub->getAttributeNS(NULL,type) : NULL);
 108     if (t.get()) {
 109         m_credResolver = XMLToolingConfig::getConfig().CredentialResolverManager.newPlugin(t.get(),sub);
 110         return;
 111     }
 112
 113     sub = e ? XMLHelper::getFirstChildElement(e, _TrustEngine) : NULL;
 114     auto_ptr_char t2(sub ? sub->getAttributeNS(NULL,type) : NULL);
 115     if (t2.get()) {
 116         TrustEngine* trust = XMLToolingConfig::getConfig().TrustEngineManager.newPlugin(t2.get(),sub);
 117         if (!(m_trust = dynamic_cast<SignatureTrustEngine*>(trust))) {
 118             delete trust;
 119             throw MetadataFilterException("TrustEngine-based SignatureMetadataFilter requires a SignatureTrustEngine plugin.");
 120         }
 121         return;
 122     }
 123
 124     throw MetadataFilterException("SignatureMetadataFilter configuration requires <CredentialResolver> or <TrustEngine> element.");
 125 }
 126
 127 void SignatureMetadataFilter::doFilter(XMLObject& xmlObject) const
 128 {
 129 #ifdef _DEBUG
 130     NDC ndc("doFilter");
 131 #endif
 132
 133     try {
 134         EntitiesDescriptor& entities = dynamic_cast<EntitiesDescriptor&>(xmlObject);
 135         doFilter(entities, true);
 136         return;
 137     }
 138     catch (bad_cast) {
 139     }
 140     catch (exception& ex) {
 141         m_log.warn("filtering out group at root of instance after failed signature check: ", ex.what());
 142         throw MetadataFilterException("SignatureMetadataFilter unable to verify signature at root of metadata instance.");
 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         return;
 151     }
 152     catch (bad_cast) {
 153     }
 154     catch (exception& ex) {
 155         m_log.warn("filtering out entity at root of instance after failed signature check: ", ex.what());
 156         throw MetadataFilterException("SignatureMetadataFilter unable to verify signature at root of metadata instance.");
 157     }
 158
 159     throw MetadataFilterException("SignatureMetadataFilter was given an improper metadata instance to filter.");
 160 }
 161
 162 void SignatureMetadataFilter::doFilter(EntitiesDescriptor& entities, bool rootObject) const
 163 {
 164     Signature* sig = entities.getSignature();
 165     if (!sig && rootObject)
 166         throw MetadataFilterException("Root metadata element was unsigned.");
 167     verifySignature(sig, entities.getName());
 168
 169     VectorOf(EntityDescriptor) v=entities.getEntityDescriptors();
 170     for (VectorOf(EntityDescriptor)::size_type i=0; i<v.size(); ) {
 171         try {
 172             verifySignature(v[i]->getSignature(), v[i]->getEntityID());
 173             i++;
 174         }
 175         catch (exception& e) {
 176             auto_ptr_char id(v[i]->getEntityID());
 177             m_log.warn("filtering out entity (%s) after failed signature check: ", id.get(), e.what());
 178             v.erase(v.begin() + i);
 179         }
 180     }
 181
 182     VectorOf(EntitiesDescriptor) w=entities.getEntitiesDescriptors();
 183     for (VectorOf(EntitiesDescriptor)::size_type j=0; j<w.size(); ) {
 184         try {
 185             doFilter(*w[j], false);
 186             j++;
 187         }
 188         catch (exception& e) {
 189             auto_ptr_char name(w[j]->getName());
 190             m_log.warn("filtering out group (%s) after failed signature check: ", name.get(), e.what());
 191             w.erase(w.begin() + j);
 192         }
 193     }
 194 }
 195
 196 void SignatureMetadataFilter::verifySignature(Signature* sig, const XMLCh* peerName) const
 197 {
 198     if (!sig)
 199         return;
 200
 201     m_profileValidator.validate(sig);
 202
 203     // Set up criteria.
 204     CredentialCriteria cc;
 205     cc.setUsage(Credential::SIGNING_CREDENTIAL);
 206     cc.setSignature(*sig, CredentialCriteria::KEYINFO_EXTRACTION_KEY);
 207     if (peerName) {
 208         auto_ptr_char pname(peerName);
 209         cc.setPeerName(pname.get());
 210     }
 211
 212     if (m_credResolver) {
 213         Locker locker(m_credResolver);
 214         vector<const Credential*> creds;
 215         if (m_credResolver->resolve(creds,&cc)) {
 216             SignatureValidator sigValidator;
 217             for (vector<const Credential*>::const_iterator i = creds.begin(); i != creds.end(); ++i) {
 218                 try {
 219                     sigValidator.setCredential(*i);
 220                     sigValidator.validate(sig);
 221                     return; // success!
 222                 }
 223                 catch (exception&) {
 224                 }
 225             }
 226             throw MetadataFilterException("CredentialResolver did not supply a successful verification key.");
 227         }
 228         else {
 229             throw MetadataFilterException("CredentialResolver did not supply a successful verification key.");
 230         }
 231     }
 232     else if (m_trust) {
 233         DummyCredentialResolver dummy;
 234         if (m_trust->validate(*sig, dummy, &cc))
 235             return;
 236         throw MetadataFilterException("TrustEngine unable to verify signature.");
 237     }
 238
 239     throw MetadataFilterException("Unable to verify signature.");
 240 }