ARC-1215: Get Keycloak GesundheitsID fit for the public (#6)

* ARC-1215: Add codeowners and license

* ARC-1215: Moar coverage

CODEOWNERS

@@ -0,0 +1 @@
+*       thomas.richner@oviva.com michele.albanese@oviva.com

LICENSE

@@ -0,0 +1,201 @@
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gesundheitsid/src/main/java/com/oviva/gesundheitsid/fedclient/FederationExceptions.java

@@ -50,6 +50,15 @@ public static RuntimeException entityStatementBadSignature(String sub) {
     return new RuntimeException("entity statement of '%s' has a bad signature".formatted(sub));
   }
 
+  public static RuntimeException federationStatementTimeNotValid(String sub) {
+    return new RuntimeException(
+        "federation statement of '%s' expired or not yet valid".formatted(sub));
+  }
+
+  public static RuntimeException federationStatementBadSignature(String sub) {
+    return new RuntimeException("federation statement of '%s' has a bad signature".formatted(sub));
+  }
+
   public static RuntimeException untrustedFederationStatement(String sub) {
     return new RuntimeException("federation statement untrusted: sub=%s".formatted(sub));
   }

gesundheitsid/src/main/java/com/oviva/gesundheitsid/fedclient/FederationMasterClientImpl.java

@@ -1,9 +1,11 @@
 package com.oviva.gesundheitsid.fedclient;
 
+import com.nimbusds.jose.jwk.JWKSet;
 import com.oviva.gesundheitsid.fedclient.api.EntityStatement;
 import com.oviva.gesundheitsid.fedclient.api.EntityStatementJWS;
 import com.oviva.gesundheitsid.fedclient.api.FederationApiClient;
 import com.oviva.gesundheitsid.fedclient.api.IdpList.IdpEntity;
+import edu.umd.cs.findbugs.annotations.NonNull;
 import java.net.URI;
 import java.time.Clock;
 import java.util.List;
@@ -36,28 +38,31 @@ public EntityStatementJWS establishIdpTrust(URI issuer) {
 
     var trustedFederationStatement = fetchTrustedFederationStatement(issuer);
 
-    if (!trustedFederationStatement.isValidAt(clock.instant())) {
-      throw FederationExceptions.entityStatementTimeNotValid(
-          trustedFederationStatement.body().sub());
-    }
-
     // the federation statement from the master will establish trust in the JWKS and the issuer URL
     // of the idp,
     // we still need to fetch the entity configuration directly afterward to get the full
     // entity statement
 
-    var idpEntitytStatement = apiClient.fetchEntityConfiguration(issuer);
-    if (!idpEntitytStatement.verifySignature(trustedFederationStatement.body().jwks())) {
-      throw FederationExceptions.untrustedFederationStatement(
-          trustedFederationStatement.body().sub());
+    return fetchTrustedEntityConfiguration(issuer, trustedFederationStatement.body().jwks());
+  }
+
+  private EntityStatementJWS fetchTrustedEntityConfiguration(@NonNull URI sub, JWKSet trustStore) {
+
+    var trustedEntityConfiguration = apiClient.fetchEntityConfiguration(sub);
+    if (!trustedEntityConfiguration.isValidAt(clock.instant())) {
+      throw FederationExceptions.entityStatementTimeNotValid(sub.toString());
+    }
+
+    if (!trustedEntityConfiguration.verifySignature(trustStore)) {
+      throw FederationExceptions.untrustedFederationStatement(sub.toString());
     }
 
-    if (!idpEntitytStatement.isValidAt(clock.instant())) {
-      throw FederationExceptions.entityStatementTimeNotValid(
-          trustedFederationStatement.body().sub());
+    if (!trustStore.equals(trustedEntityConfiguration.body().jwks())
+        && !trustedEntityConfiguration.verifySelfSigned()) {
+      throw FederationExceptions.entityStatementBadSignature(sub.toString());
     }
 
-    return idpEntitytStatement;
+    return trustedEntityConfiguration;
   }
 
   private EntityStatementJWS fetchTrustedFederationStatement(URI issuer) {
@@ -66,12 +71,23 @@ private EntityStatementJWS fetchTrustedFederationStatement(URI issuer) {
 
     var federationFetchEndpoint = getFederationFetchEndpoint(masterEntityConfiguration.body());
 
+    return fetchTrustedFederationStatement(
+        federationFetchEndpoint, masterEntityConfiguration.body().jwks(), issuer);
+  }
+
+  private EntityStatementJWS fetchTrustedFederationStatement(
+      URI federationFetchEndpoint, JWKSet fedmasterTrustStore, URI issuer) {
+
     var federationStatement =
         apiClient.fetchFederationStatement(
             federationFetchEndpoint, fedMasterUri.toString(), issuer.toString());
 
     if (!federationStatement.isValidAt(clock.instant())) {
-      throw FederationExceptions.entityStatementTimeNotValid(federationStatement.body().sub());
+      throw FederationExceptions.federationStatementTimeNotValid(federationStatement.body().sub());
+    }
+
+    if (!federationStatement.verifySignature(fedmasterTrustStore)) {
+      throw FederationExceptions.federationStatementBadSignature(issuer.toString());
     }
 
     return federationStatement;

gesundheitsid/src/main/java/com/oviva/gesundheitsid/fedclient/api/CachedFederationApiClient.java

@@ -1,5 +1,6 @@
 package com.oviva.gesundheitsid.fedclient.api;
 
+import edu.umd.cs.findbugs.annotations.NonNull;
 import java.net.URI;
 
 /** very primitive cached client, there is no cache eviction here */
@@ -24,6 +25,7 @@ public CachedFederationApiClient(
     this.idpListCache = idpListCache;
   }
 
+  @NonNull
   @Override
   public EntityStatementJWS fetchFederationStatement(
       URI federationFetchUrl, String issuer, String subject) {
@@ -32,14 +34,15 @@ public EntityStatementJWS fetchFederationStatement(
         key, k -> delegate.fetchFederationStatement(federationFetchUrl, issuer, subject));
   }
 
+  @NonNull
   @Override
   public IdpListJWS fetchIdpList(URI idpListUrl) {
     return idpListCache.computeIfAbsent(
         idpListUrl.toString(), k -> delegate.fetchIdpList(idpListUrl));
   }
 
   @Override
-  public EntityStatementJWS fetchEntityConfiguration(URI entityUrl) {
+  public @NonNull EntityStatementJWS fetchEntityConfiguration(URI entityUrl) {
     return entityStatementCache.computeIfAbsent(
         entityUrl.toString(), k -> delegate.fetchEntityConfiguration(entityUrl));
   }

gesundheitsid/src/main/java/com/oviva/gesundheitsid/fedclient/api/EntityStatement.java

@@ -113,6 +113,10 @@ public static final class Builder {
       private String contacts;
       private String homepageUri;
 
+      private String federationFetchEndpoint;
+      private String federationListEndpoint;
+      private String idpListEndpoint;
+
       private Builder() {}
 
       public Builder name(String name) {
@@ -130,8 +134,29 @@ public Builder homepageUri(String homepageUri) {
         return this;
       }
 
+      public Builder federationFetchEndpoint(String federationFetchEndpoint) {
+        this.federationFetchEndpoint = federationFetchEndpoint;
+        return this;
+      }
+
+      public Builder federationListEndpoint(String federationListEndpoint) {
+        this.federationListEndpoint = federationListEndpoint;
+        return this;
+      }
+
+      public Builder idpListEndpoint(String idpListEndpoint) {
+        this.idpListEndpoint = idpListEndpoint;
+        return this;
+      }
+
       public FederationEntity build() {
-        return new FederationEntity(name, contacts, homepageUri, null, null, null);
+        return new FederationEntity(
+            name,
+            contacts,
+            homepageUri,
+            federationFetchEndpoint,
+            federationListEndpoint,
+            idpListEndpoint);
       }
     }
   }

gesundheitsid/src/main/java/com/oviva/gesundheitsid/fedclient/api/FederationApiClient.java

@@ -1,13 +1,17 @@
 package com.oviva.gesundheitsid.fedclient.api;
 
+import edu.umd.cs.findbugs.annotations.NonNull;
 import java.net.URI;
 
 public interface FederationApiClient {
 
+  @NonNull
   EntityStatementJWS fetchFederationStatement(
       URI federationFetchUrl, String issuer, String subject);
 
+  @NonNull
   IdpListJWS fetchIdpList(URI idpListUrl);
 
+  @NonNull
   EntityStatementJWS fetchEntityConfiguration(URI entityUrl);
 }