PyYAML/CVE-2020-14343.patch

From 7adc0db3f613a82669f2b168edd98379b83adb3c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ingy=20d=C3=B6t=20Net?= <ingy@ingy.net>
Date: Sat, 9 Jan 2021 10:53:23 -0500
Subject: [PATCH] Fix for CVE-2020-14343

Per suggestion https://github.com/yaml/pyyaml/issues/420#issuecomment-663888344
move a few constructors from full_load to unsafe_load.
---
 lib/yaml/constructor.py      | 24 ++++++++++++------------
 lib3/yaml/constructor.py     | 24 ++++++++++++------------
 tests/lib/test_recursive.py  |  2 +-
 tests/lib3/test_recursive.py |  2 +-
 4 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/lib/yaml/constructor.py b/lib/yaml/constructor.py
index 794681cb..c42ee344 100644
--- a/lib/yaml/constructor.py
+++ b/lib/yaml/constructor.py
@@ -722,18 +722,6 @@ def construct_python_object_new(self, suffix, node):
     u'tag:yaml.org,2002:python/name:',
     FullConstructor.construct_python_name)
 
-FullConstructor.add_multi_constructor(
-    u'tag:yaml.org,2002:python/module:',
-    FullConstructor.construct_python_module)
-
-FullConstructor.add_multi_constructor(
-    u'tag:yaml.org,2002:python/object:',
-    FullConstructor.construct_python_object)
-
-FullConstructor.add_multi_constructor(
-    u'tag:yaml.org,2002:python/object/new:',
-    FullConstructor.construct_python_object_new)
-
 class UnsafeConstructor(FullConstructor):
 
     def find_python_module(self, name, mark):
@@ -750,6 +738,18 @@ def set_python_instance_state(self, instance, state):
         return super(UnsafeConstructor, self).set_python_instance_state(
             instance, state, unsafe=True)
 
+UnsafeConstructor.add_multi_constructor(
+    u'tag:yaml.org,2002:python/module:',
+    UnsafeConstructor.construct_python_module)
+
+UnsafeConstructor.add_multi_constructor(
+    u'tag:yaml.org,2002:python/object:',
+    UnsafeConstructor.construct_python_object)
+
+UnsafeConstructor.add_multi_constructor(
+    u'tag:yaml.org,2002:python/object/new:',
+    UnsafeConstructor.construct_python_object_new)
+
 UnsafeConstructor.add_multi_constructor(
     u'tag:yaml.org,2002:python/object/apply:',
     UnsafeConstructor.construct_python_object_apply)
diff --git a/lib3/yaml/constructor.py b/lib3/yaml/constructor.py
index 1948b125..619acd30 100644
--- a/lib3/yaml/constructor.py
+++ b/lib3/yaml/constructor.py
@@ -710,18 +710,6 @@ def construct_python_object_new(self, suffix, node):
     'tag:yaml.org,2002:python/name:',
     FullConstructor.construct_python_name)
 
-FullConstructor.add_multi_constructor(
-    'tag:yaml.org,2002:python/module:',
-    FullConstructor.construct_python_module)
-
-FullConstructor.add_multi_constructor(
-    'tag:yaml.org,2002:python/object:',
-    FullConstructor.construct_python_object)
-
-FullConstructor.add_multi_constructor(
-    'tag:yaml.org,2002:python/object/new:',
-    FullConstructor.construct_python_object_new)
-
 class UnsafeConstructor(FullConstructor):
 
     def find_python_module(self, name, mark):
@@ -738,6 +726,18 @@ def set_python_instance_state(self, instance, state):
         return super(UnsafeConstructor, self).set_python_instance_state(
             instance, state, unsafe=True)
 
+UnsafeConstructor.add_multi_constructor(
+    'tag:yaml.org,2002:python/module:',
+    UnsafeConstructor.construct_python_module)
+
+UnsafeConstructor.add_multi_constructor(
+    'tag:yaml.org,2002:python/object:',
+    UnsafeConstructor.construct_python_object)
+
+UnsafeConstructor.add_multi_constructor(
+    'tag:yaml.org,2002:python/object/new:',
+    UnsafeConstructor.construct_python_object_new)
+
 UnsafeConstructor.add_multi_constructor(
     'tag:yaml.org,2002:python/object/apply:',
     UnsafeConstructor.construct_python_object_apply)
diff --git a/tests/lib/test_recursive.py b/tests/lib/test_recursive.py
index 312204ea..04c57985 100644
--- a/tests/lib/test_recursive.py
+++ b/tests/lib/test_recursive.py
@@ -30,7 +30,7 @@ def test_recursive(recursive_filename, verbose=False):
     output2 = None
     try:
         output1 = yaml.dump(value1)
-        value2 = yaml.load(output1, yaml.FullLoader)
+        value2 = yaml.load(output1, yaml.UnsafeLoader)
         output2 = yaml.dump(value2)
         assert output1 == output2, (output1, output2)
     finally:
diff --git a/tests/lib3/test_recursive.py b/tests/lib3/test_recursive.py
index 74c2ee65..08042c81 100644
--- a/tests/lib3/test_recursive.py
+++ b/tests/lib3/test_recursive.py
@@ -31,7 +31,7 @@ def test_recursive(recursive_filename, verbose=False):
     output2 = None
     try:
         output1 = yaml.dump(value1)
-        value2 = yaml.full_load(output1)
+        value2 = yaml.unsafe_load(output1)
         output2 = yaml.dump(value2)
         assert output1 == output2, (output1, output2)
     finally: