Parse PEM Key files leniantly (#33173)

Allow for extra non-whitespace before the Header of PEM encoded
key files.

Resolves #33168

Author: jkakavas

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ssl/PemUtils.java

@@ -58,6 +58,7 @@ public class PemUtils {
     private static final String OPENSSL_EC_FOOTER = "-----END EC PRIVATE KEY-----";
     private static final String OPENSSL_EC_PARAMS_HEADER = "-----BEGIN EC PARAMETERS-----";
     private static final String OPENSSL_EC_PARAMS_FOOTER = "-----END EC PARAMETERS-----";
+    private static final String HEADER = "-----BEGIN";
 
     private PemUtils() {
         throw new IllegalStateException("Utility class should not be instantiated");
@@ -74,6 +75,9 @@ private PemUtils() {
     public static PrivateKey readPrivateKey(Path keyPath, Supplier<char[]> passwordSupplier) {
         try (BufferedReader bReader = Files.newBufferedReader(keyPath, StandardCharsets.UTF_8)) {
             String line = bReader.readLine();
+            while (null != line && line.startsWith(HEADER) == false){
+                line = bReader.readLine();
+            }
             if (null == line) {
                 throw new IllegalStateException("Error parsing Private Key from: " + keyPath.toString() + ". File is empty");
             }

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ssl/PemUtilsTests.java

@@ -32,6 +32,16 @@ public void testReadPKCS8RsaKey() throws Exception {
         assertThat(privateKey, equalTo(key));
     }
 
+    public void testReadPKCS8RsaKeyWithBagAttrs() throws Exception {
+        Key key = getKeyFromKeystore("RSA");
+        assertThat(key, notNullValue());
+        assertThat(key, instanceOf(PrivateKey.class));
+        PrivateKey privateKey = PemUtils.readPrivateKey(getDataPath
+                ("/org/elasticsearch/xpack/security/transport/ssl/certs/simple/testnode_with_bagattrs.pem"), ""::toCharArray);
+        assertThat(privateKey, notNullValue());
+        assertThat(privateKey, equalTo(key));
+    }
+
     public void testReadPKCS8DsaKey() throws Exception {
         Key key = getKeyFromKeystore("DSA");
         assertThat(key, notNullValue());

x-pack/plugin/core/src/test/resources/org/elasticsearch/xpack/security/transport/ssl/certs/simple/testnode_with_bagattrs.pem

@@ -0,0 +1,32 @@
+Bag Attributes
+    friendlyName: testnode_rsa
+    localKeyID: 54 69 6D 65 20 31 35 32 35 33 33 36 38 32 39 33 39 37 
+Key Attributes: <No Attributes>
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----