path: root/meta-python/recipes-devtools/python/python3-aiohttp/CVE-2025-69229-2.patch

From e124809ca5f17e608c09fc79423f9c357208a3c5 Mon Sep 17 00:00:00 2001
From: Gyorgy Sarvari <skandigraun@gmail.com>
Date: Sat, 3 Jan 2026 15:23:14 +0000
Subject: [PATCH 2/2] Limit number of chunks before pausing reading (#11894)
 (#11916)

From: Sam Bull <git@sambull.org>

(cherry picked from commit 1e4120e87daec963c67f956111e6bca44d7c3dea)

Co-authored-by: J. Nick Koston <nick@koston.org>

CVE: CVE-2025-69229
Upstream-Status: Backport [https://github.com/aio-libs/aiohttp/commit/4ed97a4e46eaf61bd0f05063245f613469700229]
Signed-off-by: Gyorgy Sarvari <skandigraun@gmail.com>
---
 aiohttp/streams.py    |  25 ++++++-
 tests/test_streams.py | 170 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 194 insertions(+), 1 deletion(-)

diff --git a/aiohttp/streams.py b/aiohttp/streams.py
index 108257e..9329534 100644
--- a/aiohttp/streams.py
+++ b/aiohttp/streams.py
@@ -116,6 +116,8 @@ class StreamReader(AsyncStreamReaderMixin):
         "_protocol",
         "_low_water",
         "_high_water",
+        "_low_water_chunks",
+        "_high_water_chunks",
         "_loop",
         "_size",
         "_cursor",
@@ -145,6 +147,11 @@ class StreamReader(AsyncStreamReaderMixin):
         self._high_water = limit * 2
         if loop is None:
             loop = asyncio.get_event_loop()
+        # Ensure high_water_chunks >= 3 so it's always > low_water_chunks.
+        self._high_water_chunks = max(3, limit // 4)
+        # Use max(2, ...) because there's always at least 1 chunk split remaining
+        # (the current position), so we need low_water >= 2 to allow resume.
+        self._low_water_chunks = max(2, self._high_water_chunks // 2)
         self._loop = loop
         self._size = 0
         self._cursor = 0
@@ -321,6 +328,15 @@ class StreamReader(AsyncStreamReaderMixin):
 
         self._http_chunk_splits.append(self.total_bytes)
 
+        # If we get too many small chunks before self._high_water is reached, then any
+        # .read() call becomes computationally expensive, and could block the event loop
+        # for too long, hence an additional self._high_water_chunks here.
+        if (
+            len(self._http_chunk_splits) > self._high_water_chunks
+            and not self._protocol._reading_paused
+        ):
+            self._protocol.pause_reading()
+
         # wake up readchunk when end of http chunk received
         waiter = self._waiter
         if waiter is not None:
@@ -529,7 +545,14 @@ class StreamReader(AsyncStreamReaderMixin):
         while chunk_splits and chunk_splits[0] < self._cursor:
             chunk_splits.popleft()
 
-        if self._size < self._low_water and self._protocol._reading_paused:
+        if (
+            self._protocol._reading_paused
+            and self._size < self._low_water
+            and (
+                self._http_chunk_splits is None
+                or len(self._http_chunk_splits) < self._low_water_chunks
+            )
+        ):
             self._protocol.resume_reading()
         return data
 
diff --git a/tests/test_streams.py b/tests/test_streams.py
index 1b65f77..c5bc671 100644
--- a/tests/test_streams.py
+++ b/tests/test_streams.py
@@ -1552,3 +1552,173 @@ async def test_stream_reader_iter_chunks_chunked_encoding(protocol) -> None:
 
 def test_isinstance_check() -> None:
     assert isinstance(streams.EMPTY_PAYLOAD, streams.StreamReader)
+
+
+async def test_stream_reader_pause_on_high_water_chunks(
+    protocol: mock.Mock,
+) -> None:
+    """Test that reading is paused when chunk count exceeds high water mark."""
+    loop = asyncio.get_event_loop()
+    # Use small limit so high_water_chunks is small: limit // 4 = 10
+    stream = streams.StreamReader(protocol, limit=40, loop=loop)
+
+    assert stream._high_water_chunks == 10
+    assert stream._low_water_chunks == 5
+
+    # Feed chunks until we exceed high_water_chunks
+    for i in range(12):
+        stream.begin_http_chunk_receiving()
+        stream.feed_data(b"x")  # 1 byte per chunk
+        stream.end_http_chunk_receiving()
+
+    # pause_reading should have been called when chunk count exceeded 10
+    protocol.pause_reading.assert_called()
+
+
+async def test_stream_reader_resume_on_low_water_chunks(
+    protocol: mock.Mock,
+) -> None:
+    """Test that reading resumes when chunk count drops below low water mark."""
+    loop = asyncio.get_event_loop()
+    # Use small limit so high_water_chunks is small: limit // 4 = 10
+    stream = streams.StreamReader(protocol, limit=40, loop=loop)
+
+    assert stream._high_water_chunks == 10
+    assert stream._low_water_chunks == 5
+
+    # Feed chunks until we exceed high_water_chunks
+    for i in range(12):
+        stream.begin_http_chunk_receiving()
+        stream.feed_data(b"x")  # 1 byte per chunk
+        stream.end_http_chunk_receiving()
+
+    # Simulate that reading was paused
+    protocol._reading_paused = True
+    protocol.pause_reading.reset_mock()
+
+    # Read data to reduce both size and chunk count
+    # Reading will consume chunks and reduce _http_chunk_splits
+    data = await stream.read(10)
+    assert data == b"xxxxxxxxxx"
+
+    # resume_reading should have been called when both size and chunk count
+    # dropped below their respective low water marks
+    protocol.resume_reading.assert_called()
+
+
+async def test_stream_reader_no_resume_when_chunks_still_high(
+    protocol: mock.Mock,
+) -> None:
+    """Test that reading doesn't resume if chunk count is still above low water."""
+    loop = asyncio.get_event_loop()
+    # Use small limit so high_water_chunks is small: limit // 4 = 10
+    stream = streams.StreamReader(protocol, limit=40, loop=loop)
+
+    # Feed many chunks
+    for i in range(12):
+        stream.begin_http_chunk_receiving()
+        stream.feed_data(b"x")
+        stream.end_http_chunk_receiving()
+
+    # Simulate that reading was paused
+    protocol._reading_paused = True
+
+    # Read only a few bytes - chunk count will still be high
+    data = await stream.read(2)
+    assert data == b"xx"
+
+    # resume_reading should NOT be called because chunk count is still >= low_water_chunks
+    protocol.resume_reading.assert_not_called()
+
+
+async def test_stream_reader_read_non_chunked_response(
+    protocol: mock.Mock,
+) -> None:
+    """Test that non-chunked responses work correctly (no chunk tracking)."""
+    loop = asyncio.get_event_loop()
+    stream = streams.StreamReader(protocol, limit=40, loop=loop)
+
+    # Non-chunked: just feed data without begin/end_http_chunk_receiving
+    stream.feed_data(b"Hello World")
+
+    # _http_chunk_splits should be None for non-chunked responses
+    assert stream._http_chunk_splits is None
+
+    # Reading should work without issues
+    data = await stream.read(5)
+    assert data == b"Hello"
+
+    data = await stream.read(6)
+    assert data == b" World"
+
+
+async def test_stream_reader_resume_non_chunked_when_paused(
+    protocol: mock.Mock,
+) -> None:
+    """Test that resume works for non-chunked responses when paused due to size."""
+    loop = asyncio.get_event_loop()
+    # Small limit so we can trigger pause via size
+    stream = streams.StreamReader(protocol, limit=10, loop=loop)
+
+    # Feed data that exceeds high_water (limit * 2 = 20)
+    stream.feed_data(b"x" * 25)
+
+    # Simulate that reading was paused due to size
+    protocol._reading_paused = True
+    protocol.pause_reading.assert_called()
+
+    # Read enough to drop below low_water (limit = 10)
+    data = await stream.read(20)
+    assert data == b"x" * 20
+
+    # resume_reading should be called (size is now 5 < low_water 10)
+    protocol.resume_reading.assert_called()
+
+
+@pytest.mark.parametrize("limit", [1, 2, 4])
+async def test_stream_reader_small_limit_resumes_reading(
+    protocol: mock.Mock,
+    limit: int,
+) -> None:
+    """Test that small limits still allow resume_reading to be called.
+
+    Even with very small limits, high_water_chunks should be at least 3
+    and low_water_chunks should be at least 2, with high > low to ensure
+    proper flow control.
+    """
+    loop = asyncio.get_event_loop()
+    stream = streams.StreamReader(protocol, limit=limit, loop=loop)
+
+    # Verify minimum thresholds are enforced and high > low
+    assert stream._high_water_chunks >= 3
+    assert stream._low_water_chunks >= 2
+    assert stream._high_water_chunks > stream._low_water_chunks
+
+    # Set up pause/resume side effects
+    def pause_reading() -> None:
+        protocol._reading_paused = True
+
+    protocol.pause_reading.side_effect = pause_reading
+
+    def resume_reading() -> None:
+        protocol._reading_paused = False
+
+    protocol.resume_reading.side_effect = resume_reading
+
+    # Feed 4 chunks (triggers pause at > high_water_chunks which is >= 3)
+    for char in b"abcd":
+        stream.begin_http_chunk_receiving()
+        stream.feed_data(bytes([char]))
+        stream.end_http_chunk_receiving()
+
+    # Reading should now be paused
+    assert protocol._reading_paused is True
+    assert protocol.pause_reading.called
+
+    # Read all data - should resume (chunk count drops below low_water_chunks)
+    data = stream.read_nowait()
+    assert data == b"abcd"
+    assert stream._size == 0
+
+    protocol.resume_reading.assert_called()
+    assert protocol._reading_paused is False