[Python-Dev] PEP 3147, __pycache__ directories and umask

Greg Ewing greg.ewing at canterbury.ac.nz
Tue Mar 23 00:58:16 CET 2010

Antoine Pitrou wrote:

> In light of this issue, I'm -0.5 on __pycache__ becoming the default caching
> mechanism. The directory ownership/permissions issue is too much of a mess,
> especially for Web applications (think __pycache__ files created by the Apache
> user).

Doesn't the existing .pyc mechanism have the same problem? Seems
to me it's just as insecure to allow the Apache user to create
.pyc files, since an attacker could overwrite them with arbitrary

The only safe way is to pre-compile under a different user and
make everything read-only to Apache. The same thing would apply
under the __pycache__ regime.

> Actually, __pycache__ creation doesn't have to be part of the import mechanism.
> It can be part of distutils instead (or whatever third-party tool

What about development, or if a user installs by dragging into
site-packages instead of using an installer? I don't like the
idea of being required to use an installation tool in order to
get .pyc files.


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