Fix keylog being asked with Pcapng file

On newer Android versions, the uri does not contain the ".pcapng" extension See #351
emanuele-f · Jun 16, 2024 · 8ab44d0 · 8ab44d0
1 parent 754c657
commit 8ab44d0
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Showing 2 changed files with 20 additions and 4 deletions.
diff --git a/app/src/main/java/com/emanuelef/remote_capture/Utils.java b/app/src/main/java/com/emanuelef/remote_capture/Utils.java
@@ -102,6 +102,7 @@
 import java.io.BufferedOutputStream;
 import java.io.ByteArrayInputStream;
 import java.io.Closeable;
+import java.io.DataInputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
@@ -142,8 +143,6 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.zip.GZIPInputStream;
-import java.util.zip.ZipEntry;
-import java.util.zip.ZipInputStream;
 
 import javax.net.ssl.HttpsURLConnection;
 
@@ -1789,4 +1788,21 @@ public static boolean isReadable(String path) {
             return false;
         }
     }
+
+    public static boolean isPcapng(Context ctx, Uri uri) {
+        try (InputStream in_stream = ctx.getContentResolver().openInputStream(uri)) {
+            try (DataInputStream data_in = new DataInputStream(in_stream)) {
+                int block_type = data_in.readInt();
+                data_in.skipBytes(4);
+                int magic = data_in.readInt();
+
+                return ((block_type == 0x0A0D0D0A) &&
+                        ((magic == 0x1a2b3c4d) || (magic == 0x4d3c2b1a)));
+            }
+        } catch (IOException e) {
+            Log.w(TAG, "Reading " + uri + " failed: " + e);
+        }
+
+        return false;
+    }
 }
diff --git a/app/src/main/java/com/emanuelef/remote_capture/activities/MainActivity.java b/app/src/main/java/com/emanuelef/remote_capture/activities/MainActivity.java
@@ -920,14 +920,14 @@ private void pcapFileOpenResult(final ActivityResult result) {
 
             Log.d(TAG, "pcapFileOpenResult: " + uri);
             if (mOpenPcapDecrypt &&
-                    (!mIab.isPurchased(Billing.PCAPNG_SKU) || !uri.toString().endsWith(".pcapng"))
+                    (!mIab.isPurchased(Billing.PCAPNG_SKU) || !Utils.isPcapng(this, uri))
             ) {
                 // Ask to select the keylog
                 Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
                 intent.addCategory(Intent.CATEGORY_OPENABLE);
                 intent.setType("*/*");
 
-                Log.d(TAG, "pcapFileOpenResult: launching dialog");
+                Log.i(TAG, "separate keylog file needed, launching dialog");
                 mPcapUri = uri;
                 Utils.showToast(this, R.string.select_the_keylog_file);
                 Utils.launchFileDialog(this, intent, keylogFileOpenLauncher);