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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
CVE: CVE-2022-22817
Upstream-Status: Backport
(https://github.com/python-pillow/Pillow/pull/5923/commits/8531b01d6cdf0b70f256f93092caa2a5d91afc11)
Signed-off-by: Trevor Gamblin <trevor.gamblin@windriver.com>
---
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 e7afd1ab..25811aa8 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 7f9c88e1..06bea800 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:
--
2.33.0
|
