File CVE-2022-48560-after-free-heappushpop.patch of Package python

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File CVE-2022-48560-after-free-heappushpop.patch of Package python (Revision 6a0e3499b6384cfbaba86d9162f9ae18)

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From 5179d30710e6185dc7e6a6098ab23fe068b0d85b Mon Sep 17 00:00:00 2001
From: Lumir Balhar <lbalhar@redhat.com>
Date: Thu, 23 Nov 2023 13:25:44 +0100
Subject: [PATCH] 00408-cve-2022-48560.patch
MIME-Version: 1.0
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Security fix for CVE-2022-48560: python3: use after free in heappushpop()
of heapq module
Resolved upstream: https://github.com/python/cpython/issues/83602

Backported from Python 3.6.11.

Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
Co-authored-by: Lumír Balhar <lbalhar@redhat.com>
---
 Lib/test/test_heapq.py |   32 ++++++++++++++++++++++++++++++++
 Modules/_heapqmodule.c |   31 ++++++++++++++++++++++++-------
 2 files changed, 56 insertions(+), 7 deletions(-)

--- a/Lib/test/test_heapq.py
+++ b/Lib/test/test_heapq.py
@@ -396,6 +396,38 @@ class TestErrorHandling(TestCase):
         with self.assertRaises((IndexError, RuntimeError)):
             self.module.heappop(heap)
 
+    def test_comparison_operator_modifiying_heap(self):
+        # See bpo-39421: Strong references need to be taken
+        # when comparing objects as they can alter the heap
+        class EvilClass(int):
+            def __lt__(self, o):
+                heap[:] = []
+                return NotImplemented
+
+        heap = []
+        self.module.heappush(heap, EvilClass(0))
+        self.assertRaises(IndexError, self.module.heappushpop, heap, 1)
+
+    def test_comparison_operator_modifiying_heap_two_heaps(self):
+
+        class h(int):
+            def __lt__(self, o):
+                list2[:] = []
+                return NotImplemented
+
+        class g(int):
+            def __lt__(self, o):
+                list1[:] = []
+                return NotImplemented
+
+        list1, list2 = [], []
+
+        self.module.heappush(list1, h(0))
+        self.module.heappush(list2, g(0))
+
+        self.assertRaises((IndexError, RuntimeError), self.module.heappush, list1, g(1))
+        self.assertRaises((IndexError, RuntimeError), self.module.heappush, list2, h(1))
+
 
 class TestErrorHandlingPython(TestErrorHandling):
     module = py_heapq
--- a/Modules/_heapqmodule.c
+++ b/Modules/_heapqmodule.c
@@ -52,7 +52,11 @@ _siftdown(PyListObject *heap, Py_ssize_t
     while (pos > startpos) {
         parentpos = (pos - 1) >> 1;
         parent = PyList_GET_ITEM(heap, parentpos);
+        Py_INCREF(newitem);
+        Py_INCREF(parent);
         cmp = cmp_lt(newitem, parent);
+        Py_DECREF(parent);
+        Py_DECREF(newitem);
         if (cmp == -1)
             return -1;
         if (size != PyList_GET_SIZE(heap)) {
@@ -93,9 +97,13 @@ _siftup(PyListObject *heap, Py_ssize_t p
         childpos = 2*pos + 1;    /* leftmost child position  */
         rightpos = childpos + 1;
         if (rightpos < endpos) {
-            cmp = cmp_lt(
-                PyList_GET_ITEM(heap, childpos),
-                PyList_GET_ITEM(heap, rightpos));
+            PyObject* a = PyList_GET_ITEM(heap, childpos);
+            PyObject* b = PyList_GET_ITEM(heap, rightpos);
+            Py_INCREF(a);
+            Py_INCREF(b);
+            cmp = cmp_lt(a, b);
+            Py_DECREF(a);
+            Py_DECREF(b);
             if (cmp == -1)
                 return -1;
             if (cmp == 0)
@@ -236,7 +244,10 @@ heappushpop(PyObject *self, PyObject *ar
         return item;
     }
 
-    cmp = cmp_lt(PyList_GET_ITEM(heap, 0), item);
+    PyObject* top = PyList_GET_ITEM(heap, 0);
+    Py_INCREF(top);
+    cmp = cmp_lt(top, item);
+    Py_DECREF(top);
     if (cmp == -1)
         return NULL;
     if (cmp == 0) {
@@ -395,7 +406,9 @@ _siftdownmax(PyListObject *heap, Py_ssiz
     while (pos > startpos){
         parentpos = (pos - 1) >> 1;
         parent = PyList_GET_ITEM(heap, parentpos);
+        Py_INCREF(parent);
         cmp = cmp_lt(parent, newitem);
+        Py_DECREF(parent);
         if (cmp == -1) {
             Py_DECREF(newitem);
             return -1;
@@ -436,9 +449,13 @@ _siftupmax(PyListObject *heap, Py_ssize_
         childpos = 2*pos + 1;    /* leftmost child position  */
         rightpos = childpos + 1;
         if (rightpos < endpos) {
-            cmp = cmp_lt(
-                PyList_GET_ITEM(heap, rightpos),
-                PyList_GET_ITEM(heap, childpos));
+            PyObject* a = PyList_GET_ITEM(heap, rightpos);
+            PyObject* b = PyList_GET_ITEM(heap, childpos);
+            Py_INCREF(a);
+            Py_INCREF(b);
+            cmp = cmp_lt(a, b);
+            Py_DECREF(a);
+            Py_DECREF(b);
             if (cmp == -1) {
                 Py_DECREF(newitem);
                 return -1;

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