Rename KeyVerifier to CertificateMatcher

Rename `KeyVerifier` to `CertificateMatcher` and refactor some
of the internals. This commit also adds test helper classes to
help simplify some of the tests.

See gh-38173

Author: philwebb

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ssl/CertificateMatcher.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.autoconfigure.ssl;
+
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+import java.security.Signature;
+import java.security.SignatureException;
+import java.security.cert.Certificate;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Helper used to match certificates against a {@link PrivateKey}.
+ *
+ * @author Moritz Halbritter
+ * @author Phillip Webb
+ */
+class CertificateMatcher {
+
+	private static final byte[] DATA = new byte[256];
+	static {
+		for (int i = 0; i < DATA.length; i++) {
+			DATA[i] = (byte) i;
+		}
+	}
+
+	private final PrivateKey privateKey;
+
+	private final Signature signature;
+
+	private final byte[] generatedSignature;
+
+	CertificateMatcher(PrivateKey privateKey) {
+		this.privateKey = privateKey;
+		this.signature = createSignature(privateKey);
+		this.generatedSignature = sign(this.signature, privateKey);
+	}
+
+	private Signature createSignature(PrivateKey privateKey) {
+		try {
+			String algorithm = getSignatureAlgorithm(this.privateKey);
+			return (algorithm != null) ? Signature.getInstance(algorithm) : null;
+		}
+		catch (NoSuchAlgorithmException ex) {
+			return null;
+		}
+	}
+
+	private static String getSignatureAlgorithm(PrivateKey privateKey) {
+		// https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#signature-algorithms
+		// https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#keypairgenerator-algorithms
+		return switch (privateKey.getAlgorithm()) {
+			case "RSA" -> "SHA256withRSA";
+			case "DSA" -> "SHA256withDSA";
+			case "EC" -> "SHA256withECDSA";
+			case "EdDSA" -> "EdDSA";
+			default -> null;
+		};
+	}
+
+	boolean matchesAny(List<? extends Certificate> certificates) {
+		return (this.generatedSignature != null) && certificates.stream().anyMatch(this::matches);
+	}
+
+	boolean matches(Certificate certificate) {
+		return matches(certificate.getPublicKey());
+	}
+
+	private boolean matches(PublicKey publicKey) {
+		return (this.generatedSignature != null)
+				&& Objects.equals(this.privateKey.getAlgorithm(), publicKey.getAlgorithm()) && verify(publicKey);
+	}
+
+	private boolean verify(PublicKey publicKey) {
+		try {
+			this.signature.initVerify(publicKey);
+			this.signature.update(DATA);
+			return this.signature.verify(this.generatedSignature);
+		}
+		catch (InvalidKeyException | SignatureException ex) {
+			return false;
+		}
+	}
+
+	private static byte[] sign(Signature signature, PrivateKey privateKey) {
+		try {
+			signature.initSign(privateKey);
+			signature.update(DATA);
+			return signature.sign();
+		}
+		catch (InvalidKeyException | SignatureException ex) {
+			return null;
+		}
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ssl/KeyVerifier.java

@@ -18,7 +18,6 @@
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
-import java.security.cert.X509Certificate;
 
 import org.springframework.boot.autoconfigure.ssl.SslBundleProperties.Key;
 import org.springframework.boot.ssl.SslBundle;
@@ -31,6 +30,7 @@
 import org.springframework.boot.ssl.pem.PemSslStore;
 import org.springframework.boot.ssl.pem.PemSslStoreBundle;
 import org.springframework.boot.ssl.pem.PemSslStoreDetails;
+import org.springframework.util.Assert;
 
 /**
  * {@link SslBundle} backed by {@link JksSslBundleProperties} or
@@ -122,7 +122,9 @@ private static PemSslStore asPemSslStore(PemSslBundleProperties.Store properties
 			PemSslStoreDetails details = asStoreDetails(properties, alias);
 			PemSslStore pemSslStore = PemSslStore.load(details);
 			if (properties.isVerifyKeys()) {
-				verifyPemSslStoreKeys(pemSslStore);
+				CertificateMatcher certificateMatcher = new CertificateMatcher(pemSslStore.privateKey());
+				Assert.state(certificateMatcher.matchesAny(pemSslStore.certificates()),
+						"Private key matches none of the certificates in the chain");
 			}
 			return pemSslStore;
 		}
@@ -131,17 +133,6 @@ private static PemSslStore asPemSslStore(PemSslBundleProperties.Store properties
 		}
 	}
 
-	private static void verifyPemSslStoreKeys(PemSslStore pemSslStore) {
-		KeyVerifier keyVerifier = new KeyVerifier();
-		for (X509Certificate certificate : pemSslStore.certificates()) {
-			KeyVerifier.Result result = keyVerifier.matches(pemSslStore.privateKey(), certificate.getPublicKey());
-			if (result == KeyVerifier.Result.YES) {
-				return;
-			}
-		}
-		throw new IllegalStateException("Private key matches none of the certificates in the chain");
-	}
-
 	private static PemSslStoreDetails asStoreDetails(PemSslBundleProperties.Store properties, String alias) {
 		return new PemSslStoreDetails(properties.getType(), alias, null, properties.getCertificate(),
 				properties.getPrivateKey(), properties.getPrivateKeyPassword());

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ssl/PropertiesSslBundle.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.autoconfigure.ssl;
+
+import java.security.cert.Certificate;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link CertificateMatcher}.
+ *
+ * @author Moritz Halbritter
+ * @author Phillip Webb
+ */
+class CertificateMatcherTests {
+
+	@CertificateMatchingTest
+	void matchesWhenMatchReturnsTrue(CertificateMatchingTestSource source) {
+		CertificateMatcher matcher = new CertificateMatcher(source.privateKey());
+		assertThat(matcher.matches(source.matchingCertificate())).isTrue();
+	}
+
+	@CertificateMatchingTest
+	void matchesWhenNoMatchReturnsFalse(CertificateMatchingTestSource source) {
+		CertificateMatcher matcher = new CertificateMatcher(source.privateKey());
+		for (Certificate nonMatchingCertificate : source.nonMatchingCertificates()) {
+			assertThat(matcher.matches(nonMatchingCertificate)).isFalse();
+		}
+	}
+
+	@CertificateMatchingTest
+	void matchesAnyWhenNoneMatchReturnsFalse(CertificateMatchingTestSource source) {
+		CertificateMatcher matcher = new CertificateMatcher(source.privateKey());
+		assertThat(matcher.matchesAny(source.nonMatchingCertificates())).isFalse();
+	}
+
+	@CertificateMatchingTest
+	void matchesAnyWhenOneMatchesReturnsTrue(CertificateMatchingTestSource source) {
+		CertificateMatcher matcher = new CertificateMatcher(source.privateKey());
+		List<Certificate> certificates = new ArrayList<>(source.nonMatchingCertificates());
+		certificates.add(source.matchingCertificate());
+		assertThat(matcher.matchesAny(certificates)).isTrue();
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/ssl/CertificateMatcherTests.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2012-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.autoconfigure.ssl;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+/**
+ * Annotation for a {@code ParameterizedTest @ParameterizedTest} with a
+ * {@link CertificateMatchingTestSource} parameter.
+ *
+ * @author Phillip Webb
+ */
+@Target({ ElementType.ANNOTATION_TYPE, ElementType.METHOD })
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@ParameterizedTest(name = "{0}")
+@MethodSource("org.springframework.boot.autoconfigure.ssl.CertificateMatchingTestSource#create")
+public @interface CertificateMatchingTest {
+
+}