From 378e9ad73784c5edcadf5350b776b4792876e3ea Mon Sep 17 00:00:00 2001 From: animalize Date: Mon, 7 Sep 2020 21:52:02 +0800 Subject: [PATCH] Fix thread locks in zlib module may go wrong in rare case Setting `next_in` before acquiring the thread lock may mix up compress/decompress state in other threads. --- .../next/Library/2020-09-07-21-51-17.bpo-41735.NKqGKy.rst | 1 + Modules/zlibmodule.c | 8 ++++---- 2 files changed, 5 insertions(+), 4 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2020-09-07-21-51-17.bpo-41735.NKqGKy.rst diff --git a/Misc/NEWS.d/next/Library/2020-09-07-21-51-17.bpo-41735.NKqGKy.rst b/Misc/NEWS.d/next/Library/2020-09-07-21-51-17.bpo-41735.NKqGKy.rst new file mode 100644 index 00000000000..9e36435a364 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-09-07-21-51-17.bpo-41735.NKqGKy.rst @@ -0,0 +1 @@ +Fix thread locks in zlib module may go wrong in rare case. Patch by Ma Lin. diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c index a3d9ed6646d..d6b6b01d89a 100644 --- a/Modules/zlibmodule.c +++ b/Modules/zlibmodule.c @@ -653,11 +653,11 @@ zlib_Compress_compress_impl(compobject *self, Py_buffer *data) Py_ssize_t ibuflen, obuflen = DEF_BUF_SIZE; int err; + ENTER_ZLIB(self); + self->zst.next_in = data->buf; ibuflen = data->len; - ENTER_ZLIB(self); - do { arrange_input_buffer(&self->zst, &ibuflen); @@ -771,6 +771,8 @@ zlib_Decompress_decompress_impl(compobject *self, Py_buffer *data, else hard_limit = max_length; + ENTER_ZLIB(self); + self->zst.next_in = data->buf; ibuflen = data->len; @@ -778,8 +780,6 @@ zlib_Decompress_decompress_impl(compobject *self, Py_buffer *data, if (max_length && obuflen > max_length) obuflen = max_length; - ENTER_ZLIB(self); - do { arrange_input_buffer(&self->zst, &ibuflen);