https://github.com/python/cpython/commit/57100c86baa8451a568348646834380cd42... commit: 57100c86baa8451a568348646834380cd425b858 branch: 3.10 author: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> committer: miss-islington <31488909+miss-islington@users.noreply.github.com> date: 2021-11-26T16:42:00-08:00 summary: [3.10] bpo-41735: Fix thread lock in zlib.Decompress.flush() may go wrong (GH-29587) (GH-29811) * Fix thread lock in zlib.Decompress.flush() may go wrong Getting `.unconsumed_tail` before acquiring the thread lock may mix up decompress state. (cherry picked from commit 7edb6270a78c695e4c2ae2432797dc18105374fc) Co-authored-by: Ma Lin <animalize@users.noreply.github.com> Automerge-Triggered-By: GH:gpshead files: A Misc/NEWS.d/next/Library/2021-11-16-18-13-49.bpo-41735.D72UY1.rst M Modules/zlibmodule.c diff --git a/Misc/NEWS.d/next/Library/2021-11-16-18-13-49.bpo-41735.D72UY1.rst b/Misc/NEWS.d/next/Library/2021-11-16-18-13-49.bpo-41735.D72UY1.rst new file mode 100644 index 0000000000000..101da0e9ce648 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2021-11-16-18-13-49.bpo-41735.D72UY1.rst @@ -0,0 +1 @@ +Fix thread lock in ``zlib.Decompress.flush()`` method before ``PyObject_GetBuffer``. diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c index 68de701efa45f..a6940f2fd43a3 100644 --- a/Modules/zlibmodule.c +++ b/Modules/zlibmodule.c @@ -1266,12 +1266,13 @@ zlib_Decompress_flush_impl(compobject *self, PyTypeObject *cls, return NULL; } + ENTER_ZLIB(self); + if (PyObject_GetBuffer(self->unconsumed_tail, &data, PyBUF_SIMPLE) == -1) { + LEAVE_ZLIB(self); return NULL; } - ENTER_ZLIB(self); - self->zst.next_in = data.buf; ibuflen = data.len;