MAP Client BMessage parser length

Validate and catch errors in the BMessage pertaining to erroneous
length.

Bug: 123244713
Test: atest BmessageTest
Change-Id: Ie9101e0be12d627a6fd3cec73eec9b977d8d40bb
(cherry picked from commit a353a95c230b5546a17daea10390fbd4be0f9e63)

Merged-In: Ie9101e0be12d627a6fd3cec73eec9b977d8d40bb
Change-Id: Ie83f30e898d0f81eb81100fdb70859f92680d167
diff --git a/src/com/android/bluetooth/mapclient/obex/BmessageParser.java b/src/com/android/bluetooth/mapclient/obex/BmessageParser.java
index 2705e34..5b844dc 100644
--- a/src/com/android/bluetooth/mapclient/obex/BmessageParser.java
+++ b/src/com/android/bluetooth/mapclient/obex/BmessageParser.java
@@ -309,6 +309,12 @@
         String remng = mParser.remaining();
         byte[] data = remng.getBytes();
 
+        if (offset < 0 || offset > data.length) {
+            /* Handle possible exception for incorrect LENGTH value
+             * from MSE while parsing end of props */
+            throw new ParseException("Invalid LENGTH value", mParser.pos());
+        }
+
         /* restart parsing from after 'message'<CRLF> */
         mParser = new BmsgTokenizer(new String(data, offset, data.length - offset), restartPos);
 
diff --git a/tests/unit/src/com/android/bluetooth/mapclient/BmessageTest.java b/tests/unit/src/com/android/bluetooth/mapclient/BmessageTest.java
new file mode 100644
index 0000000..acd05ed
--- /dev/null
+++ b/tests/unit/src/com/android/bluetooth/mapclient/BmessageTest.java
@@ -0,0 +1,96 @@
+/*
+ * 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.bluetooth.mapclient;
+
+import static org.mockito.Mockito.*;
+
+import androidx.test.filters.MediumTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@MediumTest
+@RunWith(AndroidJUnit4.class)
+public class BmessageTest {
+    private static final String TAG = BmessageTest.class.getSimpleName();
+    private static final String SIMPLE_MMS_MESSAGE =
+            "BEGIN:BMSG\r\nVERSION:1.0\r\nSTATUS:READ\r\nTYPE:MMS\r\nFOLDER:null\r\nBEGIN:BENV\r\n"
+            + "BEGIN:VCARD\r\nVERSION:2.1\r\nN:null;;;;\r\nTEL:555-5555\r\nEND:VCARD\r\n"
+            + "BEGIN:BBODY\r\nLENGTH:39\r\nBEGIN:MSG\r\nThis is a new msg\r\nEND:MSG\r\n"
+            + "END:BBODY\r\nEND:BENV\r\nEND:BMSG\r\n";
+
+    private static final String NO_END_MESSAGE =
+            "BEGIN:BMSG\r\nVERSION:1.0\r\nSTATUS:READ\r\nTYPE:MMS\r\nFOLDER:null\r\nBEGIN:BENV\r\n"
+            + "BEGIN:VCARD\r\nVERSION:2.1\r\nN:null;;;;\r\nTEL:555-5555\r\nEND:VCARD\r\n"
+            + "BEGIN:BBODY\r\nLENGTH:39\r\nBEGIN:MSG\r\nThis is a new msg\r\n";
+
+    private static final String WRONG_LENGTH_MESSAGE =
+            "BEGIN:BMSG\r\nVERSION:1.0\r\nSTATUS:READ\r\nTYPE:MMS\r\nFOLDER:null\r\nBEGIN:BENV\r\n"
+            + "BEGIN:VCARD\r\nVERSION:2.1\r\nN:null;;;;\r\nTEL:555-5555\r\nEND:VCARD\r\n"
+            + "BEGIN:BBODY\r\nLENGTH:200\r\nBEGIN:MSG\r\nThis is a new msg\r\nEND:MSG\r\n"
+            + "END:BBODY\r\nEND:BENV\r\nEND:BMSG\r\n";
+
+    private static final String NO_BODY_MESSAGE =
+            "BEGIN:BMSG\r\nVERSION:1.0\r\nSTATUS:READ\r\nTYPE:MMS\r\nFOLDER:null\r\nBEGIN:BENV\r\n"
+            + "BEGIN:VCARD\r\nVERSION:2.1\r\nN:null;;;;\r\nTEL:555-5555\r\nEND:VCARD\r\n"
+            + "BEGIN:BBODY\r\nLENGTH:\r\n";
+
+    private static final String NEGATIVE_LENGTH_MESSAGE =
+            "BEGIN:BMSG\r\nVERSION:1.0\r\nSTATUS:READ\r\nTYPE:MMS\r\nFOLDER:null\r\nBEGIN:BENV\r\n"
+            + "BEGIN:VCARD\r\nVERSION:2.1\r\nN:null;;;;\r\nTEL:555-5555\r\nEND:VCARD\r\n"
+            + "BEGIN:BBODY\r\nLENGTH:-1\r\nBEGIN:MSG\r\nThis is a new msg\r\nEND:MSG\r\n"
+            + "END:BBODY\r\nEND:BENV\r\nEND:BMSG\r\n";
+
+    @Test
+    public void testNormalMessages() {
+        Bmessage message = BmessageParser.createBmessage(SIMPLE_MMS_MESSAGE);
+        Assert.assertNotNull(message);
+    }
+
+    @Test
+    public void testParseWrongLengthMessage() {
+        Bmessage message = BmessageParser.createBmessage(WRONG_LENGTH_MESSAGE);
+        Assert.assertNull(message);
+    }
+
+    @Test
+    public void testParseNoEndMessage() {
+        Bmessage message = BmessageParser.createBmessage(NO_END_MESSAGE);
+        Assert.assertNull(message);
+    }
+
+    @Test
+    public void testParseReallyLongMessage() {
+        String testMessage = new String(new char[68048]).replace('\0', 'A');
+        Bmessage message = BmessageParser.createBmessage(testMessage);
+        Assert.assertNull(message);
+    }
+
+    @Test
+    public void testNoBodyMessage() {
+        Bmessage message = BmessageParser.createBmessage(NO_BODY_MESSAGE);
+        Assert.assertNull(message);
+    }
+
+    @Test
+    public void testNegativeLengthMessage() {
+        Bmessage message = BmessageParser.createBmessage(NEGATIVE_LENGTH_MESSAGE);
+        Assert.assertNull(message);
+    }
+}