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         // Use a file-based credential resolver rooted here.
 100         m_credResolver = XMLToolingConfig::getConfig().CredentialResolverManager.newPlugin(FILESYSTEM_CREDENTIAL_RESOLVER,e);
 101         return;
 102     }
 103
 104     DOMElement* sub = e ? XMLHelper::getFirstChildElement(e, _CredentialResolver) : NULL;
 105     auto_ptr_char t(sub ? sub->getAttributeNS(NULL,type) : NULL);
 106     if (t.get()) {
 107         m_credResolver = XMLToolingConfig::getConfig().CredentialResolverManager.newPlugin(t.get(),sub);
 108         return;
 109     }
 110
 111     sub = e ? XMLHelper::getFirstChildElement(e, _TrustEngine) : NULL;
 112     auto_ptr_char t2(sub ? sub->getAttributeNS(NULL,type) : NULL);
 113     if (t2.get()) {
 114         TrustEngine* trust = XMLToolingConfig::getConfig().TrustEngineManager.newPlugin(t2.get(),sub);
 115         if (!(m_trust = dynamic_cast<SignatureTrustEngine*>(trust))) {
 116             delete trust;
 117             throw MetadataFilterException("TrustEngine-based SignatureMetadataFilter requires a SignatureTrustEngine plugin.");
 118         }
 119         return;
 120     }
 121
 122     throw MetadataFilterException("SignatureMetadataFilter configuration requires <CredentialResolver> or <TrustEngine> element.");
 123 }
 124
 125 void SignatureMetadataFilter::doFilter(XMLObject& xmlObject) const
 126 {
 127 #ifdef _DEBUG
 128     NDC ndc("doFilter");
 129 #endif
 130
 131     try {
 132         EntitiesDescriptor& entities = dynamic_cast<EntitiesDescriptor&>(xmlObject);
 133         doFilter(entities, true);
 134         return;
 135     }
 136     catch (bad_cast) {
 137     }
 138
 139     try {
 140         EntityDescriptor& entity = dynamic_cast<EntityDescriptor&>(xmlObject);
 141         if (!entity.getSignature())
 142             throw MetadataFilterException("Root metadata element was unsigned.");
 143         verifySignature(entity.getSignature(), entity.getEntityID());
 144     }
 145     catch (bad_cast) {
 146     }
 147
 148     throw MetadataFilterException("SignatureMetadataFilter was given an improper metadata instance to filter.");
 149 }
 150
 151 void SignatureMetadataFilter::doFilter(EntitiesDescriptor& entities, bool rootObject) const
 152 {
 153     Category& log=Category::getInstance(SAML_LOGCAT".MetadataFilter.Signature");
 154
 155     Signature* sig = entities.getSignature();
 156     if (!sig && rootObject)
 157         throw MetadataFilterException("Root metadata element was unsigned.");
 158     verifySignature(sig, entities.getName());
 159
 160     VectorOf(EntityDescriptor) v=entities.getEntityDescriptors();
 161     for (VectorOf(EntityDescriptor)::size_type i=0; i<v.size(); ) {
 162         try {
 163             verifySignature(v[i]->getSignature(), v[i]->getEntityID());
 164             i++;
 165         }
 166         catch (exception& e) {
 167             auto_ptr_char id(v[i]->getEntityID());
 168             log.warn("filtering out entity (%s) after failed signature check: ", id.get(), e.what());
 169             v.erase(v.begin() + i);
 170         }
 171     }
 172
 173     VectorOf(EntitiesDescriptor) w=entities.getEntitiesDescriptors();
 174     for (VectorOf(EntitiesDescriptor)::size_type j=0; j<w.size(); ) {
 175         try {
 176             verifySignature(w[j]->getSignature(), w[j]->getName());
 177             j++;
 178         }
 179         catch (exception& e) {
 180             auto_ptr_char name(w[j]->getName());
 181             log.warn("filtering out group (%s) after failed signature check: ", name.get(), e.what());
 182             w.erase(w.begin() + j);
 183         }
 184     }
 185 }
 186
 187 void SignatureMetadataFilter::verifySignature(Signature* sig, const XMLCh* peerName) const
 188 {
 189     if (!sig)
 190         return;
 191
 192     m_profileValidator.validate(sig);
 193
 194     // Set up criteria.
 195     CredentialCriteria cc;
 196     cc.setUsage(Credential::SIGNING_CREDENTIAL);
 197     cc.setSignature(*sig, CredentialCriteria::KEYINFO_EXTRACTION_KEY);
 198     if (peerName) {
 199         auto_ptr_char pname(peerName);
 200         cc.setPeerName(pname.get());
 201     }
 202
 203     if (m_credResolver) {
 204         Locker locker(m_credResolver);
 205         vector<const Credential*> creds;
 206         if (m_credResolver->resolve(creds,&cc)) {
 207             SignatureValidator sigValidator;
 208             for (vector<const Credential*>::const_iterator i = creds.begin(); i != creds.end(); ++i) {
 209                 try {
 210                     sigValidator.setCredential(*i);
 211                     sigValidator.validate(sig);
 212                     return; // success!
 213                 }
 214                 catch (exception&) {
 215                 }
 216             }
 217             throw MetadataFilterException("CredentialResolver did not supply a successful verification key.");
 218         }
 219         else {
 220             throw MetadataFilterException("CredentialResolver did not supply a successful verification key.");
 221         }
 222     }
 223     else if (m_trust) {
 224         DummyCredentialResolver dummy;
 225         if (m_trust->validate(*sig, dummy, &cc))
 226             return;
 227         throw MetadataFilterException("TrustEngine unable to verify signature.");
 228     }
 229
 230     throw MetadataFilterException("Unable to verify signature.");
 231 }