From 8531b01d6cdf0b70f256f93092caa2a5d91afc11 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Sun, 2 Jan 2022 17:23:49 +1100
Subject: [PATCH] Restrict builtins for ImageMath.eval

Conflict:NA
Reference:https://github.com/python-pillow/Pillow/pull/5923/commits/8531b01d6cdf0b70f256f93092caa2a5d91afc11

---
 Tests/test_imagemath.py | 7 +++++++
 src/PIL/ImageMath.py    | 7 ++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/Tests/test_imagemath.py b/Tests/test_imagemath.py
index 2398067..8e87339 100644
--- a/Tests/test_imagemath.py
+++ b/Tests/test_imagemath.py
@@ -1,3 +1,5 @@
+import pytest
+
 from PIL import Image, ImageMath
 
 
@@ -50,6 +52,11 @@ def test_ops():
     assert pixel(ImageMath.eval("float(B)**33", images)) == "F 8589934592.0"
 
 
+def test_prevent_exec():
+    with pytest.raises(ValueError):
+        ImageMath.eval("exec('pass')")
+
+
 def test_logical():
     assert pixel(ImageMath.eval("not A", images)) == 0
     assert pixel(ImageMath.eval("A and B", images)) == "L 2"
diff --git a/src/PIL/ImageMath.py b/src/PIL/ImageMath.py
index 7f9c88e..06bea80 100644
--- a/src/PIL/ImageMath.py
+++ b/src/PIL/ImageMath.py
@@ -246,7 +246,12 @@ def eval(expression, _dict={}, **kw):
         if hasattr(v, "im"):
             args[k] = _Operand(v)
 
-    out = builtins.eval(expression, args)
+    code = compile(expression, "<string>", "eval")
+    for name in code.co_names:
+        if name not in args and name != "abs":
+            raise ValueError(f"'{name}' not allowed")
+
+    out = builtins.eval(expression, {"__builtins": {"abs": abs}}, args)
     try:
         return out.im
     except AttributeError:
-- 
2.27.0

