mobile: use GMT timezone in filenames to prevent leaking user location (#1837)

* ios: use GMT timezone in filenames to prevent leaking user location

* android: use GMT timestamp in generated file names

apps/android/app/src/main/java/chat/simplex/app/views/helpers/RecAndPlay.kt

@@ -50,8 +50,8 @@ class RecorderNative(private val recordedBytesLimit: Long): Recorder {
     rec.setAudioEncodingBitRate(16000)
     rec.setMaxDuration(MAX_VOICE_MILLIS_FOR_SENDING)
     rec.setMaxFileSize(recordedBytesLimit)
-    val timestamp = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(Date())
-    val path = getAppFilePath(SimplexApp.context, uniqueCombine(SimplexApp.context, getAppFilePath(SimplexApp.context, "voice_${timestamp}.m4a")))
+    val fileToSave = generateNewFileName(SimplexApp.context, "voice", "m4a")
+    val path = getAppFilePath(SimplexApp.context, fileToSave)
     filePath = path
     rec.setOutputFile(path)
     rec.prepare()

apps/android/app/src/main/java/chat/simplex/app/views/helpers/Util.kt

@@ -331,8 +331,7 @@ fun saveImage(context: Context, image: Bitmap): String? {
   return try {
     val ext = if (image.hasAlpha()) "png" else "jpg"
     val dataResized = resizeImageToDataSize(image, ext == "png", maxDataSize = MAX_IMAGE_SIZE)
-    val timestamp = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(Date())
-    val fileToSave = uniqueCombine(context, "IMG_${timestamp}.$ext")
+    val fileToSave = generateNewFileName(context, "IMG", ext)
     val file = File(getAppFilePath(context, fileToSave))
     val output = FileOutputStream(file)
     dataResized.writeTo(output)
@@ -355,8 +354,7 @@ fun saveAnimImage(context: Context, uri: Uri): String? {
     }
     // Just in case the image has a strange extension
     if (ext.length < 3 || ext.length > 4) ext = "gif"
-    val timestamp = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(Date())
-    val fileToSave = uniqueCombine(context, "IMG_${timestamp}.$ext")
+    val fileToSave = generateNewFileName(context, "IMG", ext)
     val file = File(getAppFilePath(context, fileToSave))
     val output = FileOutputStream(file)
     context.contentResolver.openInputStream(uri)!!.use { input ->
@@ -390,15 +388,23 @@ fun saveFileFromUri(context: Context, uri: Uri): String? {
   }
 }
 
+fun generateNewFileName(context: Context, prefix: String, ext: String): String {
+  val sdf = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US)
+  sdf.timeZone = TimeZone.getTimeZone("GMT")
+  val timestamp = sdf.format(Date())
+  return uniqueCombine(context, "${prefix}_$timestamp.$ext")
+}
+
 fun uniqueCombine(context: Context, fileName: String): String {
-  fun tryCombine(fileName: String, n: Int): String {
-    val name = File(fileName).nameWithoutExtension
-    val ext = File(fileName).extension
+  val orig = File(fileName)
+  val name = orig.nameWithoutExtension
+  val ext = orig.extension
+  fun tryCombine(n: Int): String {
     val suffix = if (n == 0) "" else "_$n"
     val f = "$name$suffix.$ext"
-    return if (File(getAppFilePath(context, f)).exists()) tryCombine(fileName, n + 1) else f
+    return if (File(getAppFilePath(context, f)).exists()) tryCombine(n + 1) else f
   }
-  return tryCombine(fileName, 0)
+  return tryCombine(0)
 }
 
 fun formatBytes(bytes: Long): String {

apps/ios/Shared/Model/ImageUtils.swift

@@ -165,8 +165,7 @@ func saveFileFromURL(_ url: URL) -> String? {
 }
 
 func generateNewFileName(_ prefix: String, _ ext: String) -> String {
-    let fileName = uniqueCombine("\(prefix)_\(getTimestamp()).\(ext)")
-    return fileName
+    uniqueCombine("\(prefix)_\(getTimestamp()).\(ext)")
 }
 
 private func uniqueCombine(_ fileName: String) -> String {
@@ -191,6 +190,7 @@ private func getTimestamp() -> String {
         df = DateFormatter()
         df.dateFormat = "yyyyMMdd_HHmmss"
         df.locale = Locale(identifier: "US")
+        df.timeZone = TimeZone(secondsFromGMT: 0)
         tsFormatter = df
     }
     return df.string(from: Date())

apps/ios/Shared/Views/Chat/ComposeMessage/ComposeView.swift

@@ -553,14 +553,16 @@ struct ComposeView: View {
                 sent = await send(checkLinkPreview(), quoted: quoted, live: live)
             case let .imagePreviews(imagePreviews: images):
                 let last = min(chosenImages.count, images.count) - 1
-                for i in 0..<last {
-                    if let savedFile = saveAnyImage(chosenImages[i]) {
-                        _ = await send(.image(text: "", image: images[i]), quoted: nil, file: savedFile)
+                if last >= 0 {
+                    for i in 0..<last {
+                        if let savedFile = saveAnyImage(chosenImages[i]) {
+                            _ = await send(.image(text: "", image: images[i]), quoted: nil, file: savedFile)
+                        }
+                        _ = try? await Task.sleep(nanoseconds: 100_000000)
+                    }
+                    if let savedFile = saveAnyImage(chosenImages[last]) {
+                        sent = await send(.image(text: msgText, image: images[last]), quoted: quoted, file: savedFile, live: live)
                     }
-                    _ = try? await Task.sleep(nanoseconds: 100_000000)
-                }
-                if let savedFile = saveAnyImage(chosenImages[last]) {
-                    sent = await send(.image(text: msgText, image: images[last]), quoted: quoted, file: savedFile, live: live)
                 }
                 if sent == nil {
                     sent = await send(.text(msgText), quoted: quoted, live: live)