gh-95231: Disable md5 & crypt modules if FIPS is enabled (GH-94742)

If kernel fips is enabled, we get permission error upon doing
`import crypt`. So, if kernel fips is enabled, disable the
unallowed hashing methods.

Python 3.9.1 (default, May 10 2022, 11:36:26)
[GCC 10.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import crypt
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.9/crypt.py", line 117, in <module>
    _add_method('MD5', '1', 8, 34)
  File "/usr/lib/python3.9/crypt.py", line 94, in _add_method
    result = crypt('', salt)
  File "/usr/lib/python3.9/crypt.py", line 82, in crypt
    return _crypt.crypt(word, salt)
PermissionError: [Errno 1] Operation not permitted

Signed-off-by: Shreenidhi Shedi <[email protected]>
(cherry picked from commit 2fa03b1)

Co-authored-by: Shreenidhi Shedi <[email protected]>

Author: miss-islington

Lib/crypt.py

@@ -98,7 +98,7 @@ def _add_method(name, *args, rounds=None):
         result = crypt('', salt)
     except OSError as e:
         # Not all libc libraries support all encryption methods.
-        if e.errno == errno.EINVAL:
+        if e.errno in {errno.EINVAL, errno.EPERM, errno.ENOSYS}:
             return False
         raise
     if result and len(result) == method.total_size:

Misc/NEWS.d/next/Library/2022-07-25-15-45-06.gh-issue-95231.i807-g.rst

@@ -0,0 +1,3 @@
+Fail gracefully if :data:`~errno.EPERM` or :data:`~errno.ENOSYS` is raised when loading
+:mod:`crypt` methods. This may happen when trying to load ``MD5`` on a Linux kernel
+with :abbr:`FIPS (Federal Information Processing Standard)` enabled.