From 11b342f3a9501a9f88a1d98f185ef0968fac312d Mon Sep 17 00:00:00 2001
From: "B. Petersen" <r10s@b44t.com>
Date: Thu, 26 Jul 2018 02:36:04 +0200
Subject: [PATCH] track a list of shared files

add message

do not export provider, we grant access explicitly
---
 MessengerProj/src/main/AndroidManifest.xml                 | 7 ++++++-
 .../src/main/java/com/b44t/messenger/AndroidUtilities.java | 4 ++++
 .../com/b44t/messenger/AttachmentsContentProvider.java     | 7 ++++++-
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/MessengerProj/src/main/AndroidManifest.xml b/MessengerProj/src/main/AndroidManifest.xml
index c9c460cbe..0cd103d1c 100644
--- a/MessengerProj/src/main/AndroidManifest.xml
+++ b/MessengerProj/src/main/AndroidManifest.xml
@@ -227,7 +227,12 @@
 
         <receiver android:name=".NotificationDismissReceiver" android:exported="false"/>
 
-        <provider android:name=".AttachmentsContentProvider" android:authorities="${applicationId}.attachments" android:exported="true" />
+        <provider
+            android:name=".AttachmentsContentProvider"
+            android:authorities="${applicationId}.attachments"
+            android:grantUriPermissions="true"
+            android:exported="false">
+        </provider>
 
         <provider
             android:name="android.support.v4.content.FileProvider"
diff --git a/MessengerProj/src/main/java/com/b44t/messenger/AndroidUtilities.java b/MessengerProj/src/main/java/com/b44t/messenger/AndroidUtilities.java
index 349cdc15e..d5d17d7f2 100644
--- a/MessengerProj/src/main/java/com/b44t/messenger/AndroidUtilities.java
+++ b/MessengerProj/src/main/java/com/b44t/messenger/AndroidUtilities.java
@@ -80,6 +80,7 @@ import java.nio.channels.FileChannel;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Date;
+import java.util.HashMap;
 import java.util.Locale;
 
 public class AndroidUtilities {
@@ -817,6 +818,8 @@ public class AndroidUtilities {
         return mimeType;
     }
 
+    public static HashMap<String, Integer> sharedFiles = new HashMap<>();
+
     public static void openForViewOrShare(Activity activity, int msg_id, String cmd)
     {
         MrMsg msg = MrMailbox.getMsg(msg_id);
@@ -832,6 +835,7 @@ public class AndroidUtilities {
             Uri uri;
             if (path.startsWith(MrMailbox.getBlobdir())) {
                 uri = Uri.parse("content://" + BuildConfig.APPLICATION_ID + ".attachments/" + file.getName());
+                sharedFiles.put("/"+file.getName(), 1); // as different Android version handle uris in putExtra differently, we also check them on our own
             } else {
                 if (Build.VERSION.SDK_INT >= 24) {
                     uri = FileProvider.getUriForFile(activity, BuildConfig.APPLICATION_ID + ".provider", file);
diff --git a/MessengerProj/src/main/java/com/b44t/messenger/AttachmentsContentProvider.java b/MessengerProj/src/main/java/com/b44t/messenger/AttachmentsContentProvider.java
index 3d4493020..720b5eeb5 100644
--- a/MessengerProj/src/main/java/com/b44t/messenger/AttachmentsContentProvider.java
+++ b/MessengerProj/src/main/java/com/b44t/messenger/AttachmentsContentProvider.java
@@ -48,7 +48,12 @@ public class AttachmentsContentProvider extends ContentProvider {
 
     @Override
     public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
-        File privateFile = new File(MrMailbox.getBlobdir(), uri.getPath());
+        String path = uri.getPath();
+        if (!AndroidUtilities.sharedFiles.containsKey(path)) {
+            throw new FileNotFoundException("File was not shared before.");
+        }
+
+        File privateFile = new File(MrMailbox.getBlobdir(), path);
         return ParcelFileDescriptor.open(privateFile, ParcelFileDescriptor.MODE_READ_ONLY);
     }