Conscrypt: correct key selection with no sigAlg

The KeyManagerImpl was changed to support the "EC_EC" and "EC_RSA" key
types in the StandardNames document. The intention of those aliases are
to require a certain signature type. If it is missing, it should accept
any signature type as before. However, it was erroneously requiring the
same signature type as the key type if it was missing. This causes RSA
client certificates signed by an EC key, for instance, to fail.

Bug: 10966884
Change-Id: I298bf65ac4c607ae13e24b44fb1b52ec341f9fcf

crypto/src/main/java/org/conscrypt/KeyManagerImpl.java

@@ -161,11 +161,11 @@ public class KeyManagerImpl extends X509ExtendedKeyManager {
                 if (keyAlgorithm == null) {
                     continue;
                 }
-                String sigAlgorithm;
+                final String sigAlgorithm;
                 // handle cases like EC_EC and EC_RSA
                 int index = keyAlgorithm.indexOf('_');
                 if (index == -1) {
-                    sigAlgorithm = keyAlgorithm;
+                    sigAlgorithm = null;
                 } else {
                     sigAlgorithm = keyAlgorithm.substring(index + 1);
                     keyAlgorithm = keyAlgorithm.substring(0, index);
@@ -181,7 +181,8 @@ public class KeyManagerImpl extends X509ExtendedKeyManager {
                  * "SHA1WithECDSA" or simply "ECDSA".
                  */
                 // sig algorithm does not match
-                if (certSigAlg != null && !certSigAlg.contains(sigAlgorithm)) {
+                if (sigAlgorithm != null && certSigAlg != null
+                        && !certSigAlg.contains(sigAlgorithm)) {
                     continue;
                 }
                 // no issuers to match, just add to return list and continue

luni/src/test/java/libcore/javax/net/ssl/X509KeyManagerTest.java

+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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 libcore.javax.net.ssl;
+
+import javax.net.ssl.KeyManager;
+import javax.net.ssl.KeyManagerFactory;
+import javax.net.ssl.X509KeyManager;
+
+import junit.framework.TestCase;
+import libcore.java.security.TestKeyStore;
+
+public class X509KeyManagerTest extends TestCase {
+    /**
+     * Tests whether the key manager will select the right key when the CA is of
+     * one key type and the client is of a possibly different key type.
+     *
+     * <p>There was a bug where EC was being interpreted as EC_EC and only
+     * accepting EC signatures when it should accept any signature type.
+     */
+    public void testChooseClientAlias_Combinations() throws Exception {
+        test_ChooseClientAlias_KeyType("RSA", "RSA", "RSA", true);
+        test_ChooseClientAlias_KeyType("RSA", "EC", "RSA", true);
+        test_ChooseClientAlias_KeyType("RSA", "EC", "EC", false);
+
+        test_ChooseClientAlias_KeyType("EC", "RSA", "EC_RSA", true);
+        test_ChooseClientAlias_KeyType("EC", "EC", "EC_RSA", false);
+
+        test_ChooseClientAlias_KeyType("EC", "EC", "EC_EC", true);
+        test_ChooseClientAlias_KeyType("EC", "RSA", "EC_EC", false);
+
+        test_ChooseClientAlias_KeyType("EC", "RSA", "RSA", false);
+    }
+
+    private void test_ChooseClientAlias_KeyType(String clientKeyType, String caKeyType,
+            String selectedKeyType, boolean succeeds) throws Exception {
+        TestKeyStore ca = new TestKeyStore.Builder()
+                .keyAlgorithms(caKeyType)
+                .build();
+        TestKeyStore client = new TestKeyStore.Builder().keyAlgorithms(clientKeyType)
+                .signer(ca.getPrivateKey(caKeyType, caKeyType))
+                .build();
+
+        KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory
+                .getDefaultAlgorithm());
+        kmf.init(client.keyStore, client.keyPassword);
+
+        String[] keyTypes = new String[] { selectedKeyType };
+        KeyManager[] managers = kmf.getKeyManagers();
+        for (KeyManager manager : managers) {
+            if (manager instanceof X509KeyManager) {
+                String alias = ((X509KeyManager) manager).chooseClientAlias(keyTypes, null, null);
+                if (succeeds) {
+                    assertNotNull(alias);
+                } else {
+                    assertNull(alias);
+                }
+            }
+        }
+    }
+}