Add X.509 Certificate Support

Closes gh-9736

Author: shazin

core/src/main/java/org/springframework/security/converter/RsaKeyConverters.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -17,10 +17,15 @@
 package org.springframework.security.converter;
 
 import java.io.BufferedReader;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.security.KeyFactory;
 import java.security.NoSuchAlgorithmException;
+import java.security.cert.CertificateException;
+import java.security.cert.CertificateFactory;
+import java.security.cert.X509Certificate;
 import java.security.interfaces.RSAPrivateKey;
 import java.security.interfaces.RSAPublicKey;
 import java.security.spec.PKCS8EncodedKeySpec;
@@ -36,6 +41,7 @@
  * Used for creating {@link java.security.Key} converter instances
  *
  * @author Josh Cummings
+ * @author Shazin Sadakath
  * @since 5.2
  */
 public final class RsaKeyConverters {
@@ -50,6 +56,10 @@ public final class RsaKeyConverters {
 
 	private static final String X509_PEM_FOOTER = DASHES + "END PUBLIC KEY" + DASHES;
 
+	private static final String X509_CERT_HEADER = DASHES + "BEGIN CERTIFICATE" + DASHES;
+
+	private static final String X509_CERT_FOOTER = DASHES + "END CERTIFICATE" + DASHES;
+
 	private RsaKeyConverters() {
 	}
 
@@ -91,8 +101,8 @@ public static Converter<InputStream, RSAPrivateKey> pkcs8() {
 	}
 
 	/**
-	 * Construct a {@link Converter} for converting a PEM-encoded X.509 RSA Public Key
-	 * into a {@link RSAPublicKey}.
+	 * Construct a {@link Converter} for converting a PEM-encoded X.509 RSA Public Key or
+	 * X.509 Certificate into a {@link RSAPublicKey}.
 	 *
 	 * This converter does not close the {@link InputStream} in order to avoid making
 	 * non-portable assumptions about the streams' origin and further use.
@@ -101,27 +111,52 @@ public static Converter<InputStream, RSAPrivateKey> pkcs8() {
 	 */
 	public static Converter<InputStream, RSAPublicKey> x509() {
 		KeyFactory keyFactory = rsaFactory();
+		CertificateFactory certificateFactory = x509CertificateFactory();
 		return (source) -> {
 			List<String> lines = readAllLines(source);
-			Assert.isTrue(!lines.isEmpty() && lines.get(0).startsWith(X509_PEM_HEADER),
-					"Key is not in PEM-encoded X.509 format, please check that the header begins with -----"
-							+ X509_PEM_HEADER + "-----");
+			Assert.isTrue(
+					!lines.isEmpty()
+							&& (lines.get(0).startsWith(X509_PEM_HEADER) || lines.get(0).startsWith(X509_CERT_HEADER)),
+					"Key is not in PEM-encoded X.509 format or a valid X.509 certificate, please check that the header begins with "
+							+ X509_PEM_HEADER + " or " + X509_CERT_HEADER);
 			StringBuilder base64Encoded = new StringBuilder();
 			for (String line : lines) {
-				if (RsaKeyConverters.isNotX509Wrapper(line)) {
+				if (RsaKeyConverters.isNotX509PemWrapper(line) && isNotX509CertificateWrapper(line)) {
 					base64Encoded.append(line);
 				}
 			}
 			byte[] x509 = Base64.getDecoder().decode(base64Encoded.toString());
-			try {
-				return (RSAPublicKey) keyFactory.generatePublic(new X509EncodedKeySpec(x509));
+			if (lines.get(0).startsWith(X509_PEM_HEADER)) {
+				try {
+					return (RSAPublicKey) keyFactory.generatePublic(new X509EncodedKeySpec(x509));
+				}
+				catch (Exception ex) {
+					throw new IllegalArgumentException(ex);
+				}
 			}
-			catch (Exception ex) {
-				throw new IllegalArgumentException(ex);
+			if (lines.get(0).startsWith(X509_CERT_HEADER)) {
+				try (InputStream x509CertStream = new ByteArrayInputStream(x509)) {
+					X509Certificate certificate = (X509Certificate) certificateFactory
+							.generateCertificate(x509CertStream);
+					return (RSAPublicKey) certificate.getPublicKey();
+				}
+				catch (CertificateException | IOException ex) {
+					throw new IllegalArgumentException(ex);
+				}
 			}
+			return null;
 		};
 	}
 
+	private static CertificateFactory x509CertificateFactory() {
+		try {
+			return CertificateFactory.getInstance("X.509");
+		}
+		catch (CertificateException ex) {
+			throw new IllegalArgumentException(ex);
+		}
+	}
+
 	private static List<String> readAllLines(InputStream source) {
 		BufferedReader reader = new BufferedReader(new InputStreamReader(source));
 		return reader.lines().collect(Collectors.toList());
@@ -140,8 +175,12 @@ private static boolean isNotPkcs8Wrapper(String line) {
 		return !PKCS8_PEM_HEADER.equals(line) && !PKCS8_PEM_FOOTER.equals(line);
 	}
 
-	private static boolean isNotX509Wrapper(String line) {
+	private static boolean isNotX509PemWrapper(String line) {
 		return !X509_PEM_HEADER.equals(line) && !X509_PEM_FOOTER.equals(line);
 	}
 
+	private static boolean isNotX509CertificateWrapper(String line) {
+		return !X509_CERT_HEADER.equals(line) && !X509_CERT_FOOTER.equals(line);
+	}
+
 }

core/src/test/java/org/springframework/security/converter/RsaKeyConvertersTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -93,6 +93,20 @@ public class RsaKeyConvertersTests {
 			+ "-----END PUBLIC KEY-----";
 	// @formatter:on
 
+	// @formatter:off
+	private static final String X509_CERTIFICATE = "-----BEGIN CERTIFICATE-----\n" +
+			"MIIBqDCCARECBgF5zJA6MjANBgkqhkiG9w0BAQsFADAaMRgwFgYDVQQDEw9TaGF6\n" +
+			"aW4gU2FkYWthdGgwHhcNMjEwNjAxMTE1MTE0WhcNMjEwNTE3MjAwOTI1WjAaMRgw\n" +
+			"FgYDVQQDEw9TaGF6aW4gU2FkYWthdGgwgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJ\n" +
+			"AoGBAKsKpS6sliNSri3koOAgzS7Nz2cpl0tGpNP3GPuUYVMP4MA0LJ2+blxjxUcn\n" +
+			"oIajtaf9HljFetKVjyARp1zjZ3Oxm//lfmyqqI5KDUjqe5J2rdtbdFCH9FXUEoGD\n" +
+			"mu2ameR9lAfxtaGI58DGS9uJ5hvGJoIvLiaDUfv1qZ+kIwG7AgMBAAEwDQYJKoZI\n" +
+			"hvcNAQELBQADgYEAWdIIi4cGPod5O/V7K0QSTXZRLRIKFQ7qhn5XTNlMUnFnwp7c\n" +
+			"8O8EsOiCKAZeVvgRnurFkxAlVnpxmdktZ9j+mv2mrMGKJxYkZcBkFh++DRixpY8N\n" +
+			"zBLbxZJ9kcOHWWDA602FMbNIEL1OiHrfggsPk3sckSaSg4d7UoP9T6+uqq8=\n" +
+			"-----END CERTIFICATE-----";
+	// @formatter:on
+
 	private static final String MALFORMED_X509_KEY = "malformed";
 
 	private final Converter<InputStream, RSAPublicKey> x509 = RsaKeyConverters.x509();
@@ -112,11 +126,17 @@ public void pkcs8WhenConvertingPkcs1PrivateKeyThenIllegalArgumentException() {
 	}
 
 	@Test
-	public void x509WhenConverteringX509PublicKeyThenOk() {
+	public void x509WhenConvertingX509PublicKeyThenOk() {
 		RSAPublicKey key = this.x509.convert(toInputStream(X509_PUBLIC_KEY));
 		Assertions.assertThat(key.getModulus().bitLength()).isEqualTo(1024);
 	}
 
+	@Test
+	public void x509WhenConvertingX509CertificateThenOk() {
+		RSAPublicKey key = this.x509.convert(toInputStream(X509_CERTIFICATE));
+		Assertions.assertThat(key.getModulus().bitLength()).isEqualTo(1024);
+	}
+
 	@Test
 	public void x509WhenConvertingDerEncodedX509PublicKeyThenIllegalArgumentException() {
 		assertThatIllegalArgumentException().isThrownBy(() -> this.x509.convert(toInputStream(MALFORMED_X509_KEY)));