Add test for CVE-2022-21699

IPython/tests/cve.py

@@ -0,0 +1,56 b''
+"""
+Test that CVEs stay fixed. 
+"""
+
+from IPython.utils.tempdir import TemporaryDirectory, TemporaryWorkingDirectory
+from pathlib import Path
+import random
+import sys
+import os
+import string
+import subprocess
+import time
+
+def test_cve_2022_21699():
+    """
+    Here we test CVE-2022-21699.
+
+    We create a temporary directory, cd into it. 
+    Make a profile file that should not be executed and start IPython in a subprocess, 
+    checking for the value.
+
+
+
+    """
+
+    dangerous_profile_dir = Path('profile_default')
+
+    dangerous_startup_dir = dangerous_profile_dir / 'startup'
+    dangerous_expected = 'CVE-2022-21699-'+''.join([random.choice(string.ascii_letters) for i in range(10)])
+
+    with TemporaryWorkingDirectory() as t:
+        dangerous_startup_dir.mkdir(parents=True)
+        (dangerous_startup_dir/ 'foo.py').write_text(f'print("{dangerous_expected}")')
+        # 1 sec to make sure FS is flushed.
+        #time.sleep(1)
+        cmd = [sys.executable,'-m', 'IPython']
+        env = os.environ.copy()
+        env['IPY_TEST_SIMPLE_PROMPT'] = '1'
+
+
+        # First we fake old behavior, making sure the profile is/was actually dangerous
+        p_dangerous = subprocess.Popen(cmd + [f'--profile-dir={dangerous_profile_dir}'], env=env, stdin=subprocess.PIPE,
+                stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        out_dangerous, err_dangerouns = p_dangerous.communicate(b"exit\r")
+        assert dangerous_expected in out_dangerous.decode()
+
+        # Now that we know it _would_ have been dangerous, we test it's not loaded
+        p = subprocess.Popen(cmd, env=env, stdin=subprocess.PIPE,
+                stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        out, err = p.communicate(b"exit\r")
+        assert b'IPython' in out
+        assert dangerous_expected not in out.decode()
+        assert err == b''
+
+
+