OPP: Restrict file based URI access to external storage

Change-Id: Icad55763f2478586544a4bbd233b820c7f69b658
diff --git a/src/com/android/bluetooth/opp/BluetoothOppHandoverReceiver.java b/src/com/android/bluetooth/opp/BluetoothOppHandoverReceiver.java
index 3553d34..4f03c96 100644
--- a/src/com/android/bluetooth/opp/BluetoothOppHandoverReceiver.java
+++ b/src/com/android/bluetooth/opp/BluetoothOppHandoverReceiver.java
@@ -59,7 +59,7 @@
                 Thread t = new Thread(new Runnable() {
                     public void run() {
                         BluetoothOppManager.getInstance(context).saveSendingFileInfo(finalType,
-                            finalUris, true);
+                                finalUris, true /* isHandover */, true /* fromExternal */);
                         BluetoothOppManager.getInstance(context).startTransfer(device);
                     }
                 });
diff --git a/src/com/android/bluetooth/opp/BluetoothOppLauncherActivity.java b/src/com/android/bluetooth/opp/BluetoothOppLauncherActivity.java
index 0d4b5b2..c298745 100644
--- a/src/com/android/bluetooth/opp/BluetoothOppLauncherActivity.java
+++ b/src/com/android/bluetooth/opp/BluetoothOppLauncherActivity.java
@@ -112,7 +112,8 @@
                     Thread t = new Thread(new Runnable() {
                         public void run() {
                             BluetoothOppManager.getInstance(BluetoothOppLauncherActivity.this)
-                                .saveSendingFileInfo(type,stream.toString(), false);
+                                .saveSendingFileInfo(type,stream.toString(),
+                                    false /* isHandover */, true /* fromExternal */);
                             //Done getting file info..Launch device picker and finish this activity
                             launchDevicePicker();
                             finish();
@@ -128,7 +129,8 @@
                         Thread t = new Thread(new Runnable() {
                             public void run() {
                                 BluetoothOppManager.getInstance(BluetoothOppLauncherActivity.this)
-                                    .saveSendingFileInfo(type,fileUri.toString(), false);
+                                    .saveSendingFileInfo(type,fileUri.toString(),
+                                        false /* isHandover */, false /* fromExternal */);
                                 //Done getting file info..Launch device picker
                                 //and finish this activity
                                 launchDevicePicker();
@@ -156,7 +158,8 @@
                     Thread t = new Thread(new Runnable() {
                         public void run() {
                             BluetoothOppManager.getInstance(BluetoothOppLauncherActivity.this)
-                                .saveSendingFileInfo(mimeType,uris, false);
+                                .saveSendingFileInfo(mimeType,uris,
+                                    false /* isHandover */, true /* fromExternal */);
                             //Done getting file info..Launch device picker
                             //and finish this activity
                             launchDevicePicker();
diff --git a/src/com/android/bluetooth/opp/BluetoothOppManager.java b/src/com/android/bluetooth/opp/BluetoothOppManager.java
index dd8efe0..39929aa 100644
--- a/src/com/android/bluetooth/opp/BluetoothOppManager.java
+++ b/src/com/android/bluetooth/opp/BluetoothOppManager.java
@@ -246,28 +246,32 @@
         if (V) Log.v(TAG, "Application data stored to SharedPreference! ");
     }
 
-    public void saveSendingFileInfo(String mimeType, String uriString, boolean isHandover) {
+    public void saveSendingFileInfo(String mimeType, String uriString, boolean isHandover,
+            boolean fromExternal) {
         synchronized (BluetoothOppManager.this) {
             mMultipleFlag = false;
             mMimeTypeOfSendingFile = mimeType;
             mUriOfSendingFile = uriString;
             mIsHandoverInitiated = isHandover;
             Uri uri = Uri.parse(uriString);
-            BluetoothOppUtility.putSendFileInfo(uri,
-                    BluetoothOppSendFileInfo.generateFileInfo(mContext, uri, mimeType));
+            BluetoothOppUtility.putSendFileInfo(
+                    uri, BluetoothOppSendFileInfo.generateFileInfo(
+                                 mContext, uri, mimeType, fromExternal));
             storeApplicationData();
         }
     }
 
-    public void saveSendingFileInfo(String mimeType, ArrayList<Uri> uris, boolean isHandover) {
+    public void saveSendingFileInfo(String mimeType, ArrayList<Uri> uris, boolean isHandover,
+            boolean fromExternal) {
         synchronized (BluetoothOppManager.this) {
             mMultipleFlag = true;
             mMimeTypeOfSendingFiles = mimeType;
             mUrisOfSendingFiles = uris;
             mIsHandoverInitiated = isHandover;
             for (Uri uri : uris) {
-                BluetoothOppUtility.putSendFileInfo(uri,
-                        BluetoothOppSendFileInfo.generateFileInfo(mContext, uri, mimeType));
+                BluetoothOppUtility.putSendFileInfo(
+                        uri, BluetoothOppSendFileInfo.generateFileInfo(
+                                     mContext, uri, mimeType, fromExternal));
             }
             storeApplicationData();
         }
diff --git a/src/com/android/bluetooth/opp/BluetoothOppSendFileInfo.java b/src/com/android/bluetooth/opp/BluetoothOppSendFileInfo.java
index b9d2b9f..84ebc82 100644
--- a/src/com/android/bluetooth/opp/BluetoothOppSendFileInfo.java
+++ b/src/com/android/bluetooth/opp/BluetoothOppSendFileInfo.java
@@ -39,6 +39,7 @@
 import android.database.sqlite.SQLiteException;
 import android.net.Uri;
 import android.provider.OpenableColumns;
+import android.util.EventLog;
 import android.util.Log;
 
 import java.io.File;
@@ -97,8 +98,8 @@
         mStatus = status;
     }
 
-    public static BluetoothOppSendFileInfo generateFileInfo(Context context, Uri uri,
-            String type) {
+    public static BluetoothOppSendFileInfo generateFileInfo(
+            Context context, Uri uri, String type, boolean fromExternal) {
         ContentResolver contentResolver = context.getContentResolver();
         String scheme = uri.getScheme();
         String fileName = null;
@@ -140,6 +141,16 @@
                 fileName = uri.getLastPathSegment();
             }
         } else if ("file".equals(scheme)) {
+            if (uri.getPath() == null) {
+                Log.e(TAG, "Invalid URI path: " + uri);
+                return SEND_FILE_INFO_ERROR;
+            }
+            if (fromExternal && !BluetoothOppUtility.isInExternalStorageDir(uri)) {
+                EventLog.writeEvent(0x534e4554, "35310991", -1, uri.getPath());
+                Log.e(TAG,
+                        "File based URI not in Environment.getExternalStorageDirectory() is not allowed.");
+                return SEND_FILE_INFO_ERROR;
+            }
             fileName = uri.getLastPathSegment();
             contentType = type;
             File f = new File(uri.getPath());
diff --git a/src/com/android/bluetooth/opp/BluetoothOppUtility.java b/src/com/android/bluetooth/opp/BluetoothOppUtility.java
index bd671b2..6b94ab5 100644
--- a/src/com/android/bluetooth/opp/BluetoothOppUtility.java
+++ b/src/com/android/bluetooth/opp/BluetoothOppUtility.java
@@ -39,6 +39,7 @@
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
 import android.net.Uri;
+import android.content.ContentResolver;
 import android.content.ContentValues;
 import android.content.Context;
 import android.content.ActivityNotFoundException;
@@ -46,6 +47,7 @@
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
 import android.database.Cursor;
+import android.os.Environment;
 import android.util.Log;
 
 import java.io.File;
@@ -353,4 +355,40 @@
             }
         }
     }
+
+    /**
+     * Checks if the URI is in Environment.getExternalStorageDirectory() as it
+     * is the only directory that is possibly readable by both the sender and
+     * the Bluetooth process.
+     */
+    static boolean isInExternalStorageDir(Uri uri) {
+        if (!ContentResolver.SCHEME_FILE.equals(uri.getScheme())) {
+            Log.e(TAG, "Not a file URI: " + uri);
+            return false;
+        }
+        final File file = new File(uri.getCanonicalUri().getPath());
+        return isSameOrSubDirectory(Environment.getExternalStorageDirectory(), file);
+    }
+
+    /**
+     * Checks, whether the child directory is the same as, or a sub-directory of the base
+     * directory. Neither base nor child should be null.
+     */
+    static boolean isSameOrSubDirectory(File base, File child) {
+        try {
+            base = base.getCanonicalFile();
+            child = child.getCanonicalFile();
+            File parentFile = child;
+            while (parentFile != null) {
+                if (base.equals(parentFile)) {
+                    return true;
+                }
+                parentFile = parentFile.getParentFile();
+            }
+            return false;
+        } catch (IOException ex) {
+            Log.e(TAG, "Error while accessing file", ex);
+            return false;
+        }
+    }
 }