From a1dcf28bf93f7206f8e43d17ff3edfdbcc2ebf9b Mon Sep 17 00:00:00 2001
From: evgeny <evgeny@adaptto.ru>
Date: Thu, 29 Oct 2026 00:42:19 +0100
Subject: [PATCH] Reject malformed stream batches before mutating the playback
 queue

---
 .../com/utun/chat/data/StreamReadQueue.kt     | 18 ++++++++++++------
 .../com/utun/chat/data/StreamReadQueueTest.kt | 19 +++++++++++++++++++
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamReadQueue.kt b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamReadQueue.kt
index 51419205..42a91e56 100644
--- a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamReadQueue.kt
+++ b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamReadQueue.kt
@@ -4,7 +4,10 @@ import java.nio.ByteBuffer
 import java.nio.ByteOrder
 
 /** Ближайшие записи viewer: порядок каждого трека независим, EOF не ждёт чужой трек.
- * GAP/CLOSED отменяют прежние данные. Только player worker; ошибки логирует его владелец. */
+ * GAP/CLOSED отменяют прежние данные. add принимает до 16 BE записей (header 28 bytes + payload)
+ * и проверяет всю пачку до изменения очереди; при ошибке очередь сохраняется.
+ * take разрешает EOF обойти другой трек, сохраняя порядок собственного. Только player worker;
+ * ограничение общей очереди/backpressure задаёт caller, он же логирует исключения. */
 internal class StreamReadQueue {
     private val records = mutableListOf<ByteArray>()
     val size: Int get() = records.size
@@ -14,19 +17,22 @@ internal class StreamReadQueue {
 
     fun add(batch: ByteArray): Int {
         val input = ByteBuffer.wrap(batch).order(ByteOrder.BIG_ENDIAN)
-        var count = 0
+        val parsed = mutableListOf<ByteArray>()
         while (input.hasRemaining()) {
             check(input.remaining() >= 28) { "Truncated stream record header" }
             val start = input.position()
             val kind = batch[start].toInt()
             val length = input.getInt(start + 16)
             check(kind in 1..8 && length >= 0 && length <= input.remaining() - 28) { "Invalid stream record kind=$kind length=$length" }
-            if (kind == 3 || kind == 6) records.clear()
-            records.add(batch.copyOfRange(start, start + 28 + length))
+            check(parsed.size < 16) { "Stream batch exceeds record budget" }
+            parsed.add(batch.copyOfRange(start, start + 28 + length))
             input.position(start + 28 + length)
-            check(++count <= 16) { "Stream batch exceeds record budget" }
         }
-        return count
+        for (record in parsed) {
+            if (record[0].toInt() in listOf(3, 6)) records.clear()
+            records.add(record)
+        }
+        return parsed.size
     }
 
     fun take(video: Boolean, audio: Boolean): ByteArray? {
diff --git a/tools/chatgui-android/app/src/test/java/com/utun/chat/data/StreamReadQueueTest.kt b/tools/chatgui-android/app/src/test/java/com/utun/chat/data/StreamReadQueueTest.kt
index 33997a5f..32c9663a 100644
--- a/tools/chatgui-android/app/src/test/java/com/utun/chat/data/StreamReadQueueTest.kt
+++ b/tools/chatgui-android/app/src/test/java/com/utun/chat/data/StreamReadQueueTest.kt
@@ -52,4 +52,23 @@ class StreamReadQueueTest {
         assertArrayEquals(audio, queue.take(video = false, audio = true))
         assertArrayEquals(video, queue.take(video = true, audio = false))
     }
+
+    @Test fun malformedTailCannotApplyItsEarlierGapOrReplacePendingData() {
+        val queue = StreamReadQueue(); val original = record(1, 42)
+        queue.add(original)
+        for (invalid in listOf(record(3) + byteArrayOf(1), record(6) + record(9),
+            record(2) + record(1).also { ByteBuffer.wrap(it).putInt(16, 100) })) {
+            assertThrows(IllegalStateException::class.java) { queue.add(invalid) }
+            assertEquals(1, queue.size)
+        }
+        assertArrayEquals(original, queue.take(video = true, audio = true))
+    }
+
+    @Test fun excessiveRecordCountIsRejectedBeforeAnyChange() {
+        val queue = StreamReadQueue(); val original = record(2, 123)
+        queue.add(original)
+        val invalid = List(17) { record(3) }.fold(byteArrayOf()) { bytes, next -> bytes + next }
+        assertThrows(IllegalStateException::class.java) { queue.add(invalid) }
+        assertEquals(1, queue.size); assertArrayEquals(original, queue.take(video = true, audio = true))
+    }
 }