1 files changed, 85 insertions, 0 deletions
diff --git a/security-utils/src/main/java/com/yahoo/security/tls/PeerAuthorizer.java b/security-utils/src/main/java/com/yahoo/security/tls/PeerAuthorizer.java
new file mode 100644
index 00000000000..e026c611d0c
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+++ b/security-utils/src/main/java/com/yahoo/security/tls/PeerAuthorizer.java
@@ -0,0 +1,85 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.security.tls;
+
+import com.yahoo.security.SubjectAlternativeName;
+import com.yahoo.security.X509CertificateUtils;
+
+import java.security.cert.X509Certificate;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import java.util.logging.Logger;
+
+import static com.yahoo.security.SubjectAlternativeName.Type.DNS_NAME;
+import static com.yahoo.security.SubjectAlternativeName.Type.IP_ADDRESS;
+import static com.yahoo.security.SubjectAlternativeName.Type.UNIFORM_RESOURCE_IDENTIFIER;
+import static java.util.stream.Collectors.toList;
+
+/**
+ * Uses rules from {@link AuthorizedPeers} to evaluate X509 certificates
+ *
+ * @author bjorncs
+ */
+public class PeerAuthorizer {
+
+    private static final Logger log = Logger.getLogger(PeerAuthorizer.class.getName());
+
+    private final AuthorizedPeers authorizedPeers;
+
+    public PeerAuthorizer(AuthorizedPeers authorizedPeers) {
+        this.authorizedPeers = authorizedPeers;
+    }
+
+
+    public ConnectionAuthContext authorizePeer(X509Certificate cert) { return authorizePeer(List.of(cert)); }
+
+    public ConnectionAuthContext authorizePeer(List<X509Certificate> certChain) {
+        if (authorizedPeers.isEmpty()) {
+            return new ConnectionAuthContext(certChain, CapabilitySet.all(), Set.of());
+        }
+        X509Certificate cert = certChain.get(0);
+        Set<String> matchedPolicies = new HashSet<>();
+        Set<CapabilitySet> grantedCapabilities = new HashSet<>();
+        String cn = getCommonName(cert).orElse(null);
+        List<String> sans = getSubjectAlternativeNames(cert);
+        log.fine(() -> String.format("Subject info from x509 certificate: CN=[%s], 'SAN=%s", cn, sans));
+        for (PeerPolicy peerPolicy : authorizedPeers.peerPolicies()) {
+            if (matchesPolicy(peerPolicy, cn, sans)) {
+                matchedPolicies.add(peerPolicy.policyName());
+                grantedCapabilities.add(peerPolicy.capabilities());
+            }
+        }
+        return new ConnectionAuthContext(certChain, CapabilitySet.unionOf(grantedCapabilities), matchedPolicies);
+    }
+
+    private static boolean matchesPolicy(PeerPolicy peerPolicy, String cn, List<String> sans) {
+        return peerPolicy.requiredCredentials().stream()
+                .allMatch(requiredCredential -> matchesRequiredCredentials(requiredCredential, cn, sans));
+    }
+
+    private static boolean matchesRequiredCredentials(RequiredPeerCredential requiredCredential, String cn, List<String> sans) {
+        switch (requiredCredential.field()) {
+            case CN:
+                return cn != null && requiredCredential.pattern().matches(cn);
+            case SAN_DNS:
+            case SAN_URI:
+                return sans.stream()
+                        .anyMatch(san -> requiredCredential.pattern().matches(san));
+            default:
+                throw new RuntimeException("Unknown field: " + requiredCredential.field());
+        }
+    }
+
+    private static Optional<String> getCommonName(X509Certificate peerCertificate) {
+        return X509CertificateUtils.getSubjectCommonNames(peerCertificate).stream()
+                .findFirst();
+    }
+
+    private static List<String> getSubjectAlternativeNames(X509Certificate peerCertificate) {
+        return X509CertificateUtils.getSubjectAlternativeNames(peerCertificate).stream()
+                .filter(san -> san.getType() == DNS_NAME || san.getType() == IP_ADDRESS || san.getType() == UNIFORM_RESOURCE_IDENTIFIER)
+                .map(SubjectAlternativeName::getValue)
+                .collect(toList());
+    }
+}