Decode auth payload that uses digital signature

This commit:
- Create IkeAuthDigitalSignPayload for payload that uses digital
  signature
- Decode auth payload that uses RSA signature for IKE auth
- Decode auth payload that uses generic digital signature for
  IKE auth

Bug: 122688641
Test: FrameworksIkeTests IkeAuthDigitalSignPayloadTest
      HexUtilsTest
Change-Id: Ie2363ee848d33511eb3e6bb94e955d996b0d22d1

3 files changed, 66 insertions, 5 deletions

diff --git a/tests/iketests/src/java/com/android/ike/ikev2/message/IkeAuthDigitalSignPayloadTest.java b/tests/iketests/src/java/com/android/ike/ikev2/message/IkeAuthDigitalSignPayloadTest.java
new file mode 100644
index 00000000..a2c4d1f0
--- /dev/null
+++ b/tests/iketests/src/java/com/android/ike/ikev2/message/IkeAuthDigitalSignPayloadTest.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2019 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 com.android.ike.ikev2.message;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public final class IkeAuthDigitalSignPayloadTest {
+
+    private static final String AUTH_PAYLOAD_BODY_GENERIC_DIGITAL_SIGN_HEX_STRING =
+            "0e0000000f300d06092a864886f70d01010b05007b2f4456878b1344e803f094"
+                    + "159a59361bc639071b69de41915452c478b77a46ce4a2c96ddc7ba2c18d08406"
+                    + "50ce51c77124605423a2f75d8ed4b5a1ec5944c3396221a39e25def09abe5c9f"
+                    + "6d9cd70e8f6254d4c835015256c9d6c26f0c6d31ac96a2ed802ccb16e48e7ff3"
+                    + "daf736221b18c2a972130a69edb197a505a312882baed95d38a47bf6784533f2"
+                    + "ffee671d742b5ae463216e46ef970ee6a335ffb3fc9c170a680fb802bb950cb0"
+                    + "5601339be8869a73f8f85254d792b6e91697d8893ccd34b5fb6aad6268c4ab0f"
+                    + "9ead7b3f8a4a255e1b2eabfa3da0de284f3954cf49271918dd2d2db95c8e7812"
+                    + "9aea77e5761ac5683a0b5af300ceb52f5e8d8168";
+    // TODO: Build a RSA_SHA1 signature and add tests for it.
+
+    @Test
+    public void testDecodeGenericDigitalSignPayload() throws Exception {
+        byte[] inputPacket =
+                TestUtils.hexStringToByteArray(AUTH_PAYLOAD_BODY_GENERIC_DIGITAL_SIGN_HEX_STRING);
+        IkeAuthPayload payload = IkeAuthPayload.getIkeAuthPayload(false, inputPacket);
+
+        assertTrue(payload instanceof IkeAuthDigitalSignPayload);
+        IkeAuthDigitalSignPayload dsPayload = (IkeAuthDigitalSignPayload) payload;
+        assertEquals(
+                IkeAuthDigitalSignPayload.SIGNATURE_ALGO_RSA_SHA2_256,
+                dsPayload.signatureAlgoAndHash);
+    }
+}
diff --git a/tests/iketests/src/java/com/android/ike/ikev2/message/IkeNoncePayloadTest.java b/tests/iketests/src/java/com/android/ike/ikev2/message/IkeNoncePayloadTest.java
index a15507c5..f4e4a984 100644
--- a/tests/iketests/src/java/com/android/ike/ikev2/message/IkeNoncePayloadTest.java
+++ b/tests/iketests/src/java/com/android/ike/ikev2/message/IkeNoncePayloadTest.java
@@ -41,7 +41,7 @@ public final class IkeNoncePayloadTest {
         payload.encodeToByteBuffer(NEXT_PAYLOAD_TYPE, byteBuffer);
 
         byte[] expectedNoncePayload =
-        TestUtils.hexStringToByteArray(NONCE_PAYLOAD_RAW_HEX_STRING);
+                TestUtils.hexStringToByteArray(NONCE_PAYLOAD_RAW_HEX_STRING);
         assertArrayEquals(expectedNoncePayload, byteBuffer.array());
     }
 }
diff --git a/tests/iketests/src/java/com/android/ike/ikev2/message/TestUtils.java b/tests/iketests/src/java/com/android/ike/ikev2/message/TestUtils.java
index d1c82ddd..e77e799d 100644
--- a/tests/iketests/src/java/com/android/ike/ikev2/message/TestUtils.java
+++ b/tests/iketests/src/java/com/android/ike/ikev2/message/TestUtils.java
@@ -16,15 +16,26 @@
 
 package com.android.ike.ikev2.message;
 
+/** TestUtils provides utility methods for parsing Hex String */
 public final class TestUtils {
-    static byte[] hexStringToByteArray(String s) {
-        int len = s.length();
+    /**
+     * Converts the unsigned Hex String to a byte array.
+     *
+     * @param hexString hex representation of an unsigned value.
+     * @return the converted byte array.
+     * @throws IllegalArgumentException when length of Hex String is an odd number.
+     */
+    public static byte[] hexStringToByteArray(String hexString) throws IllegalArgumentException {
+        int len = hexString.length();
+        if (len % 2 != 0) {
+            throw new IllegalArgumentException("Invalid Hex String");
+        }
         byte[] data = new byte[len / 2];
         for (int i = 0; i < len; i += 2) {
             data[i / 2] =
                     (byte)
-                            ((Character.digit(s.charAt(i), 16) << 4)
-                                    + Character.digit(s.charAt(i + 1), 16));
+                            ((Character.digit(hexString.charAt(i), 16) << 4)
+                                    + Character.digit(hexString.charAt(i + 1), 16));
         }
         return data;
     }