[Python-checkins] [3.12] gh-105375: Improve _pickle error handling (#105475) (#105584)

Fri Jun 9 14:08:39 EDT 2023

https://github.com/python/cpython/commit/04b76ece7f92bd7e46ca2f3b46e7a42cfd75fa05
commit: 04b76ece7f92bd7e46ca2f3b46e7a42cfd75fa05
branch: 3.12
author: Erlend E. Aasland <erlend.aasland at protonmail.com>
committer: erlend-aasland <erlend.aasland at protonmail.com>
date: 2023年06月09日T18:08:32Z
summary:
[3.12] gh-105375: Improve _pickle error handling (#105475) (#105584)
(cherry picked from commit 89aac6f6b7b3af046ec137121c90732289e79efc)
Error handling was deferred in some cases, which could potentially lead
to exceptions being overwritten.
files:
A Misc/NEWS.d/next/Library/2023-06-08-08-58-36.gh-issue-105375.bTcqS9.rst
M Modules/_pickle.c

diff --git a/Misc/NEWS.d/next/Library/2023-06-08-08-58-36.gh-issue-105375.bTcqS9.rst b/Misc/NEWS.d/next/Library/2023-06-08-08-58-36.gh-issue-105375.bTcqS9.rst
new file mode 100644
index 0000000000000..3030477c8245b
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-06-08-08-58-36.gh-issue-105375.bTcqS9.rst
@@ -0,0 +1 @@
+Fix bugs in :mod:`pickle` where exceptions could be overwritten.
diff --git a/Modules/_pickle.c b/Modules/_pickle.c
index bf7ecae0cc0e5..d6a273b1044e4 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -1168,10 +1168,13 @@ _Pickler_New(PickleState *st)
 self->reducer_override = NULL;
 
 self->memo = PyMemoTable_New();
+ if (self->memo == NULL) {
+ Py_DECREF(self);
+ return NULL;
+ }
 self->output_buffer = PyBytes_FromStringAndSize(NULL,
 self->max_output_len);
-
- if (self->memo == NULL || self->output_buffer == NULL) {
+ if (self->output_buffer == NULL) {
 Py_DECREF(self);
 return NULL;
 }
@@ -1654,9 +1657,12 @@ _Unpickler_New(PyObject *module)
 self->memo_size = 32;
 self->memo_len = 0;
 self->memo = _Unpickler_NewMemo(self->memo_size);
+ if (self->memo == NULL) {
+ Py_DECREF(self);
+ return NULL;
+ }
 self->stack = (Pdata *)Pdata_New(st);
-
- if (self->memo == NULL || self->stack == NULL) {
+ if (self->stack == NULL) {
 Py_DECREF(self);
 return NULL;
 }
@@ -4834,11 +4840,12 @@ _pickle_PicklerMemoProxy_copy_impl(PicklerMemoProxyObject *self)
 PyObject *key, *value;
 
 key = PyLong_FromVoidPtr(entry.me_key);
+ if (key == NULL) {
+ goto error;
+ }
 value = Py_BuildValue("nO", entry.me_value, entry.me_key);
-
- if (key == NULL || value == NULL) {
- Py_XDECREF(key);
- Py_XDECREF(value);
+ if (value == NULL) {
+ Py_DECREF(key);
 goto error;
 }
 status = PyDict_SetItem(new_memo, key, value);
@@ -5994,12 +6001,20 @@ load_stack_global(PickleState *st, UnpicklerObject *self)
 PyObject *global_name;
 
 PDATA_POP(st, self->stack, global_name);
+ if (global_name == NULL) {
+ return -1;
+ }
 PDATA_POP(st, self->stack, module_name);
- if (module_name == NULL || !PyUnicode_CheckExact(module_name) ||
- global_name == NULL || !PyUnicode_CheckExact(global_name)) {
+ if (module_name == NULL) {
+ Py_DECREF(global_name);
+ return -1;
+ }
+ if (!PyUnicode_CheckExact(module_name) ||
+ !PyUnicode_CheckExact(global_name))
+ {
 PyErr_SetString(st->UnpicklingError, "STACK_GLOBAL requires str");
- Py_XDECREF(global_name);
- Py_XDECREF(module_name);
+ Py_DECREF(global_name);
+ Py_DECREF(module_name);
 return -1;
 }
 global = find_class(self, module_name, global_name);
