python3-aiohttp: fix CVE-2026-111066

Backport the multipart descriptor-exhaustion fix [1] to aiohttp 3.13.5. Spool small file parts in memory and count raw multipart bytes, including headers, against client_max_size. Include the upstream descriptor-test correction [2] so unrelated file descriptors do not make the regression test unreliable. Adapt the HTTP 413 constructor and retain the existing read size. The vulnerability and fixed release are documented in [3]. [1] https://github.com/aio-libs/aiohttp/commit/2d94633b7f1b4c1ba07d647b629a8440652b2d09 [2] https://github.com/aio-libs/aiohttp/commit/011c08204197beba8281911907b59ffcecea1413 [3] https://github.com/aio-libs/aiohttp/security/advisories/GHSA-9xw5-w5jj-pvcg Signed-off-by: Darsh Kelaiya <dkelaiya@cisco.com> Signed-off-by: Anuj Mittal <anuj.mittal@oss.qualcomm.com>
2026-11-14 03:57:15 +00:00 · 2026-11-09 09:10:47 +05:30
1 parent 45251809f1
commit ba8d0af836
@@ -0,0 +1,400 @@
+From 2d94633b7f1b4c1ba07d647b629a8440652b2d09 Mon Sep 17 00:00:00 2001
+From: Sam Bull <git@sambull.org>
+Date: Tue, 18 Aug 2026 21:54:45 +0100
+Subject: [PATCH] Reduce number of file descriptors needed in multipart
+ messages (#13426) (#13475)
+
+(cherry picked from commit c92ed4c48dafd40d5ed4c86587af9e081ac7d971)
+
+CVE: CVE-2026-111066
+Upstream-Status: Backport [https://github.com/aio-libs/aiohttp/commit/2d94633b7f1b4c1ba07d647b629a8440652b2d09]
+
+Backport Changes:
+- Pass the raw payload size to the older HTTP 413 constructor and
+  update the existing test to match upstream's size-limit assertion.
+- Keep the existing type annotations and surrounding test signatures.
+
+Signed-off-by: Darsh Kelaiya <dkelaiya@cisco.com>
+---
+ CHANGES/13426.bugfix.rst     |   1 +
+ aiohttp/web_request.py       |  96 +++++++++++++++-----
+ tests/test_web_functional.py | 167 ++++++++++++++++++++++++++++++++++-
+ 3 files changed, 237 insertions(+), 27 deletions(-)
+ create mode 100644 CHANGES/13426.bugfix.rst
+
+diff --git a/CHANGES/13426.bugfix.rst b/CHANGES/13426.bugfix.rst
+new file mode 100644
+index 0000000..8b9ee29
+--- /dev/null
+++ b/CHANGES/13426.bugfix.rst
+@@ -0,0 +1 @@
+Switched multipart handling to use spooled temporary files to reduce number of file descriptors needed -- by :user:`Dreamsorcerer`.
+diff --git a/aiohttp/web_request.py b/aiohttp/web_request.py
+index f2d4c51..e978b2a 100644
+--- a/aiohttp/web_request.py
+++ b/aiohttp/web_request.py
+@@ -4,11 +4,12 @@ import io
+ import re
+ import socket
+ import string
+-import tempfile
+import sys
+ import types
+ import warnings
+ from types import MappingProxyType
+ from typing import (
+    IO,
+     TYPE_CHECKING,
+     Any,
+     Dict,
+@@ -64,6 +65,30 @@ from .typedefs import (
+ from .web_exceptions import HTTPRequestEntityTooLarge
+ from .web_response import StreamResponse
+ 
+if sys.version_info >= (3, 11):
+    from tempfile import SpooledTemporaryFile
+else:
+    import tempfile
+
+    class SpooledTemporaryFile(tempfile.SpooledTemporaryFile[bytes], io.IOBase):
+        """Make the spooled file satisfy the documented `FileField.file` type.
+
+        `tempfile.SpooledTemporaryFile` only became an `io.IOBase` subclass in
+        3.11 (python/cpython#70363), and never grew the three capability
+        predicates before then. Both underlying files (`io.BytesIO` before
+        rollover, a `w+b` temp file after) are readable, writable and seekable.
+        """
+
+        def readable(self) -> bool:
+            return True
+
+        def writable(self) -> bool:
+            return True
+
+        def seekable(self) -> bool:
+            return True
+
+
+ __all__ = ("BaseRequest", "FileField", "Request")
+ 
+ 
+@@ -73,11 +98,18 @@ if TYPE_CHECKING:
+     from .web_urldispatcher import UrlMappingMatchInfo
+ 
+ 
+# Multipart file parts are buffered in memory and only spilled to a temporary
+# file once they outgrow this size. A temp file per part would let a body made
+# of many tiny parts exhaust the process's file descriptors; spooling bounds
+# that at ``client_max_size // _FILE_SPOOL_MAX_SIZE`` descriptors per request.
+_FILE_SPOOL_MAX_SIZE: Final[int] = 1024**2
+
+
+ @attr.s(auto_attribs=True, frozen=True, slots=True)
+ class FileField:
+     name: str
+     filename: str
+-    file: io.BufferedReader
+    file: IO[bytes]
+     content_type: str
+     headers: CIMultiDictProxy[str]
+ 
+@@ -726,8 +758,15 @@ class BaseRequest(MutableMapping[str, Any], HeadersMixin):
+             multipart = await self.multipart()
+             max_size = self._client_max_size
+ 
+-            size = 0
+            payload = self._payload
+             while (field := await multipart.next()) is not None:
+                # This check is needed for empty payloads, which still add
+                # overhead without entering the loop and the check below.
+                if 0 < max_size < payload.total_bytes:
+                    raise HTTPRequestEntityTooLarge(
+                        max_size=max_size, actual_size=payload.total_bytes
+                    )
+
+                 field_ct = field.headers.get(hdrs.CONTENT_TYPE)
+ 
+                 if isinstance(field, BodyPartReader):
+@@ -739,22 +778,37 @@ class BaseRequest(MutableMapping[str, Any], HeadersMixin):
+                     # present.
+                     # https://tools.ietf.org/html/rfc7578#section-4.4
+                     if field.filename:
+-                        # store file in temp file
+-                        tmp = await self._loop.run_in_executor(
+-                            None, tempfile.TemporaryFile
+-                        )
+                        tmp = SpooledTemporaryFile(_FILE_SPOOL_MAX_SIZE)
+                        # rolled means the temp file now uses the disk, at
+                        # which point we want to run in the executor.
+                        rolled = False
+                         while chunk := await field.read_chunk(size=2**18):
+                            # Bounds one part, mid-read.
+                            if 0 < max_size < payload.total_bytes:
+                                if rolled:
+                                    await self._loop.run_in_executor(None, tmp.close)
+                                else:
+                                    tmp.close()
+                                raise HTTPRequestEntityTooLarge(
+                                    max_size=max_size, actual_size=payload.total_bytes
+                                )
+                             async for decoded_chunk in field.decode_iter(chunk):
+-                                await self._loop.run_in_executor(
+-                                    None, tmp.write, decoded_chunk
+                                # Update before writing, so we know if next
+                                # write is going to hit the disk.
+                                rolled = rolled or (
+                                    tmp.tell() + len(decoded_chunk)
+                                    > _FILE_SPOOL_MAX_SIZE
+                                 )
+-                                size += len(decoded_chunk)
+-                                if 0 < max_size < size:
+-                                    await self._loop.run_in_executor(None, tmp.close)
+-                                    raise HTTPRequestEntityTooLarge(
+-                                        max_size=max_size, actual_size=size
+                                if rolled:
+                                    await self._loop.run_in_executor(
+                                        None, tmp.write, decoded_chunk
+                                     )
+-                        await self._loop.run_in_executor(None, tmp.seek, 0)
+                                else:
+                                    tmp.write(decoded_chunk)
+                        if rolled:
+                            await self._loop.run_in_executor(None, tmp.seek, 0)
+                        else:
+                            tmp.seek(0)
+ 
+                         if field_ct is None:
+                             field_ct = "application/octet-stream"
+@@ -762,7 +816,7 @@ class BaseRequest(MutableMapping[str, Any], HeadersMixin):
+                         ff = FileField(
+                             field.name,
+                             field.filename,
+-                            cast(io.BufferedReader, tmp),
+                            tmp,
+                             field_ct,
+                             field.headers,
+                         )
+@@ -771,10 +825,9 @@ class BaseRequest(MutableMapping[str, Any], HeadersMixin):
+                         # deal with ordinary data
+                         raw_data = bytearray()
+                         while chunk := await field.read_chunk():
+-                            size += len(chunk)
+-                            if 0 < max_size < size:
+                            if 0 < max_size < payload.total_bytes:
+                                 raise HTTPRequestEntityTooLarge(
+-                                    max_size=max_size, actual_size=size
+                                    max_size=max_size, actual_size=payload.total_bytes
+                                 )
+                             raw_data.extend(chunk)
+ 
+@@ -843,10 +896,7 @@ class BaseRequest(MutableMapping[str, Any], HeadersMixin):
+         if self._post is None or self.content_type != "multipart/form-data":
+             return
+ 
+-        # NOTE: Release file descriptors for the
+-        # NOTE: `tempfile.Temporaryfile`-created `_io.BufferedRandom`
+-        # NOTE: instances of files sent within multipart request body
+-        # NOTE: via HTTP POST request.
+        # Release the temp files created within multipart request body.
+         for file_name, file_field_object in self._post.items():
+             if isinstance(file_field_object, FileField):
+                 file_field_object.file.close()
+diff --git a/tests/test_web_functional.py b/tests/test_web_functional.py
+index 0d2824a..a314d9b 100644
+--- a/tests/test_web_functional.py
+++ b/tests/test_web_functional.py
+@@ -1,6 +1,8 @@
+ import asyncio
+import base64
+ import io
+ import json
+import os
+ import pathlib
+ import socket
+ import sys
+@@ -29,6 +31,7 @@ from aiohttp.pytest_plugin import AiohttpClient, AiohttpServer
+ from aiohttp.streams import StreamReader
+ from aiohttp.typedefs import Handler
+ from aiohttp.web_protocol import MAX_MSG_QUEUE_SIZE, RequestHandler
+from aiohttp.web_request import _FILE_SPOOL_MAX_SIZE
+ 
+ try:
+     import brotlicffi as brotli
+@@ -2023,10 +2026,7 @@ async def test_post_max_client_size(aiohttp_client) -> None:
+ 
+         assert 413 == resp.status
+         resp_text = await resp.text()
+-        assert (
+-            "Maximum request body size 10 exceeded, "
+-            "actual body size 1024" in resp_text
+-        )
+        assert "Maximum request body size 10 exceeded" in resp_text
+         data["file"].close()
+ 
+         await resp.release()
+@@ -2050,6 +2050,165 @@ async def test_post_max_client_size_for_file(aiohttp_client) -> None:
+     await resp.release()
+ 
+ 
+def _multipart_file_parts(count: int, body: bytes = b"") -> bytes:
+    """Raw multipart/form-data body of ``count`` file parts, boundary ``b``."""
+    return (
+        b"".join(
+            b'--b\r\nContent-Disposition: form-data; name="f%d"; '
+            b'filename="x"\r\n\r\n' % index + body + b"\r\n"
+            for index in range(count)
+        )
+        + b"--b--\r\n"
+    )
+
+
+async def test_post_max_client_size_counts_multipart_headers(
+    aiohttp_client: AiohttpClient,
+) -> None:
+    async def handler(request: web.Request) -> NoReturn:
+        await request.post()
+        assert False
+
+    app = web.Application(client_max_size=1)
+    app.router.add_post("/", handler)
+    client = await aiohttp_client(app)
+
+    body = _multipart_file_parts(55)
+    assert len(body) > 1
+    async with client.post(
+        "/", data=body, headers={CONTENT_TYPE: "multipart/form-data; boundary=b"}
+    ) as resp:
+        assert resp.status == 413
+
+
+@pytest.mark.parametrize(
+    "max_size",
+    (_FILE_SPOOL_MAX_SIZE, 2 * _FILE_SPOOL_MAX_SIZE),
+    ids=("spooled", "rolled-over"),
+)
+async def test_post_max_client_size_within_single_part(
+    aiohttp_client: AiohttpClient, max_size: int
+) -> None:
+    async def handler(request: web.Request) -> NoReturn:
+        await request.post()
+        assert False
+
+    app = web.Application(client_max_size=max_size)
+    app.router.add_post("/", handler)
+    client = await aiohttp_client(app)
+
+    # A sole oversized part is never followed by a boundary, so only the
+    # per-chunk check can reject it, and it must do so before buffering. The
+    # larger limit lets the part reach the disk first, so the spool is then
+    # closed off the event loop too.
+    data = FormData()
+    with io.BytesIO(b"x" * (3 * _FILE_SPOOL_MAX_SIZE)) as file_handle:
+        data.add_field("file", file_handle, filename="x.bin")
+        async with client.post("/", data=data) as resp:
+            assert resp.status == 413
+
+
+@pytest.mark.parametrize("filename", (b"", b'; filename="x"'), ids=("field", "file"))
+async def test_post_max_client_size_counts_undecoded_bytes(
+    aiohttp_client: AiohttpClient, filename: bytes
+) -> None:
+    async def handler(request: web.Request) -> NoReturn:
+        await request.post()
+        assert False
+
+    limit = 64 * 1024
+    app = web.Application(client_max_size=limit)
+    app.router.add_post("/", handler)
+    client = await aiohttp_client(app)
+
+    # base64 decodes to exactly the limit but arrives 4/3 larger. The limit is
+    # on the request body, so both kinds of part must reject it alike.
+    encoded = base64.b64encode(b"A" * limit)
+    assert len(encoded) > limit
+    body = (
+        b'--b\r\nContent-Disposition: form-data; name="f"' + filename + b"\r\n"
+        b"Content-Transfer-Encoding: base64\r\n\r\n" + encoded + b"\r\n--b--\r\n"
+    )
+    async with client.post(
+        "/", data=body, headers={CONTENT_TYPE: "multipart/form-data; boundary=b"}
+    ) as resp:
+        assert resp.status == 413
+
+
+@pytest.mark.skipif(not os.path.isdir("/dev/fd"), reason="needs /dev/fd to count fds")
+@pytest.mark.parametrize(
+    ("parts", "part_body", "expected_fds"),
+    (
+        (55, b"payload", 0),
+        (1, b"x" * (_FILE_SPOOL_MAX_SIZE + 1), 1),
+    ),
+    ids=("many-small-parts", "one-oversized-part"),
+)
+async def test_post_file_fields_descriptor_cost(
+    aiohttp_client: AiohttpClient, parts: int, part_body: bytes, expected_fds: int
+) -> None:
+    """Only a part past the spool size may cost a descriptor."""
+
+    async def handler(request: web.Request) -> web.Response:
+        before = set(await asyncio.to_thread(os.listdir, "/dev/fd"))
+        data = await request.post()
+        after = set(await asyncio.to_thread(os.listdir, "/dev/fd"))
+        assert len(data) == parts
+        return web.Response(text=str(len(after - before)))
+
+    app = web.Application(client_max_size=8 * 1024**2)
+    app.router.add_post("/", handler)
+    client = await aiohttp_client(app)
+
+    with io.BytesIO(_multipart_file_parts(parts, part_body)) as body:
+        async with client.post(
+            "/",
+            data=body,
+            headers={CONTENT_TYPE: "multipart/form-data; boundary=b"},
+        ) as resp:
+            assert resp.status == 200
+            assert await resp.text() == str(expected_fds)
+
+
+@pytest.mark.parametrize(
+    "size",
+    (
+        0,
+        1,
+        _FILE_SPOOL_MAX_SIZE - 1,
+        _FILE_SPOOL_MAX_SIZE,
+        _FILE_SPOOL_MAX_SIZE + 1,
+    ),
+)
+async def test_post_file_field_spool_rollover(
+    aiohttp_client: AiohttpClient, size: int
+) -> None:
+    """A part is byte-identical either side of the spool/temp-file boundary."""
+    payload = (b"0123456789abcdef" * (size // 16 + 1))[:size]
+
+    async def handler(request: web.Request) -> web.Response:
+        field = (await request.post())["file"]
+        assert isinstance(field, aiohttp.web_request.FileField)
+        assert isinstance(field.file, io.IOBase)
+        assert field.file.readable()
+        assert field.file.writable()
+        assert field.file.seekable()
+        content = await asyncio.to_thread(field.file.read)
+        assert len(content) == size
+        assert content == payload
+        return web.Response()
+
+    app = web.Application(client_max_size=8 * 1024**2)
+    app.router.add_post("/", handler)
+    client = await aiohttp_client(app)
+
+    data = FormData()
+    with io.BytesIO(payload) as file_handle:
+        data.add_field("file", file_handle, filename="x.bin")
+        async with client.post("/", data=data) as resp:
+            assert resp.status == 200
+
+
+ async def test_response_with_bodypart(aiohttp_client) -> None:
+     async def handler(request):
+         reader = await request.multipart()
@@ -0,0 +1,57 @@
+From 011c08204197beba8281911907b59ffcecea1413 Mon Sep 17 00:00:00 2001
+From: "patchback[bot]" <45432694+patchback[bot]@users.noreply.github.com>
+Date: Wed, 26 Aug 2026 02:39:52 +0100
+Subject: [PATCH] [PR #13549/4602990f backport][3.14] Fix flaky descriptor test
+ (#13551)
+
+**This is a backport of PR #13549 as merged into master
+(4602990f60241f759f861a3a4c1243ba2294ab53).**
+
+Co-authored-by: Sam Bull <git@sambull.org>
+
+CVE: CVE-2026-111066
+Upstream-Status: Backport [https://github.com/aio-libs/aiohttp/commit/011c08204197beba8281911907b59ffcecea1413]
+
+Signed-off-by: Darsh Kelaiya <dkelaiya@cisco.com>
+---
+ tests/test_web_functional.py | 20 +++++++++++++++++---
+ 1 file changed, 17 insertions(+), 3 deletions(-)
+
+diff --git a/tests/test_web_functional.py b/tests/test_web_functional.py
+index a314d9b..9fafd52 100644
+--- a/tests/test_web_functional.py
+++ b/tests/test_web_functional.py
+@@ -2135,7 +2135,9 @@ async def test_post_max_client_size_counts_undecoded_bytes(
+         assert resp.status == 413
+ 
+ 
+-@pytest.mark.skipif(not os.path.isdir("/dev/fd"), reason="needs /dev/fd to count fds")
+@pytest.mark.skipif(
+    not os.path.isdir("/proc/self/fd"), reason="needs /proc/self/fd to identify fds"
+)
+ @pytest.mark.parametrize(
+     ("parts", "part_body", "expected_fds"),
+     (
+@@ -2150,8 +2152,20 @@ async def test_post_file_fields_descriptor_cost(
+     """Only a part past the spool size may cost a descriptor."""
+ 
+    def deleted_file_fds() -> set[tuple[str, str]]:
+        """(fd, symlink target) pairs for open fds backed by deleted files."""
+        fds = set()
+        for name in os.listdir("/proc/self/fd"):
+            try:
+                target = os.readlink(f"/proc/self/fd/{name}")
+            except OSError:
+                continue  # closed between listdir and readlink
+            if target.endswith("(deleted)"):
+                fds.add((name, target))
+        return fds
+
+     async def handler(request: web.Request) -> web.Response:
+-        before = set(await asyncio.to_thread(os.listdir, "/dev/fd"))
+        before = await asyncio.to_thread(deleted_file_fds)
+         data = await request.post()
+-        after = set(await asyncio.to_thread(os.listdir, "/dev/fd"))
+        after = await asyncio.to_thread(deleted_file_fds)
+         assert len(data) == parts
+         return web.Response(text=str(len(after - before)))
@@ -22,6 +22,8 @@ SRC_URI += " \
    file://CVE-2026-59881.patch \
    file://CVE-2026-69243.patch \
    file://CVE-2026-69244.patch \
+    file://CVE-2026-111066_p1.patch \
+    file://CVE-2026-111066_p2.patch \
 "

 CVE_PRODUCT = "aiohttp:aiohttp"