On 04/17/2012 02:10 PM, Matthias Runge wrote:

On 17/04/12 19:43, Adam Young wrote:

...

While looking into EPEL support for Openstack, we came across the issue that EPEL ships with 1.2.7 and Openstack expects 1.3. Upon looking at https://docs.djangoproject.com/en/1.3/releases/1.3/#backwards-incompatible-c...

I see that one of the major differences is protection against XSRF. This alone is sufficient reason to upgrade.

Installing an RPM from the Sourceforge site worked well with Openstack, so it seems to fit our needs as well.

Are there any objections to upgrading EPEL's version of Django To the latest?

Umh, my fault. I'm planning to upgrade django for epel6 to version 1.3.x since two weeks now; sadly, real life kept me really busy.

There have been some requests to upgrade to version 1.4 (to skip 1.3.x). I'm aware of at least one application, which would break, if we upgrade to django-1,4: reviewboard. So, I'd do an update to django-1.3.1 in the next few days. An additional reason to upgrade is, that django developers only support the two latest versions, so 1.2.7 is not actively maintained any more.

If you can provide a 1.4 RPM, I am willing to test Openstack against it. I suspect we can move to that more slowly, but we'll be ahead of the curve.

On 17/04/12 21:29, Adam Young wrote:

If you can provide a 1.4 RPM, I am willing to test Openstack against it. I suspect we can move to that more slowly, but we'll be ahead of the curve.

Ok, could you please try this one here:

http://www.matthias-runge.de/fedora/Django-1.4-2.el6.noarch.rpm

-docs: http://www.matthias-runge.de/fedora/Django-doc-1.4-2.el6.noarch.rpm

and (for anyone interested:)

http://www.matthias-runge.de/fedora/Django-1.4-2.el6.src.rpm

(all of them taken from f17).

Matthias

On Tue, 2012-04-17 at 20:10 +0200, Matthias Runge wrote:

On 17/04/12 19:43, Adam Young wrote:

...

While looking into EPEL support for Openstack, we came across the issue that EPEL ships with 1.2.7 and Openstack expects 1.3. Upon looking at https://docs.djangoproject.com/en/1.3/releases/1.3/#backwards-incompatible-c... I see that one of the major differences is protection against XSRF. This alone is sufficient reason to upgrade.

Installing an RPM from the Sourceforge site worked well with Openstack, so it seems to fit our needs as well.

Are there any objections to upgrading EPEL's version of Django To the latest?

Umh, my fault. I'm planning to upgrade django for epel6 to version 1.3.x since two weeks now; sadly, real life kept me really busy.

There have been some requests to upgrade to version 1.4 (to skip 1.3.x). I'm aware of at least one application, which would break, if we upgrade to django-1,4: reviewboard. So, I'd do an update to django-1.3.1 in the next few days. An additional reason to upgrade is, that django developers only support the two latest versions, so 1.2.7 is not actively maintained any more.

Yes, ReviewBoard currently cannot work with Django 1.4. This is a known issue and last I heard probably won't be fixed until ReviewBoard 1.7.0 (not yet in beta release).

However, now that your 1.3.1 packages are in updates-testing, I have been able to package up ReviewBoard 1.6.5 which requires Django 1.3, so thanks for that. :) There are a lot of improvements in the 1.6.x series that I think people will like.

https://admin.fedoraproject.org/updates/django-evolution-0.6.7-1.el6,python-...

On Fri, Apr 20, 2012 at 09:42:26AM -0400, Adam Young wrote:

One caveat. Any DJango app (Probably most Python wsgi apps, actually) is going to give an AVC Denial warning upon startup.

Only a denial? ;-) Do you have selinux in permissive?

DJango imports Python's UUID module which in turn imports ctypes. Ctypes does dynamic code generation, specifically by writing a file andd then trying to execute it, which, as you can imagine, is a pretty big security hole. Let the wsgi community know that, until we have that fixed, we should not attempt to get rid of the AVC denial warning message, but instead should push on the Python upstread to get a fix in. Yes, David Malcolm is aware of it.

https://bugzilla.redhat.com/show_bug.cgi?id=814391

That's sorta a duplicate of this bug; https://bugzilla.redhat.com/show_bug.cgi?id=582009

(AFAICS, they're the same, but yours is against RHEL and mine is against Fedora).

I discussed it with dmalcolm when I opened it in 2010 -- it's not easily solvable.

* By its nature, libffi needs to generate code that it then executes. * Because python is interpreted, selinux has no transition to tell it that this is a specific program that needs to be able to write and execute specific files * Because the python interpreter is being embedded inside of apache, selinux has no way of differentiating it from any other piece of apache.

The way out that I suggested in 2010 was to have a search path. Python would loop through the search path to find which directory it could use to write its temporary files for ffi. We'd need a way to set this path when applications start up (maybe in their httpd.conf) as mod_wsgi allows applications to run as different users than apache (which means that each wsgi application might need a different ffi directory). The sysadmin or wsgi application package would be responsible for creating the ffi directory and setting the appropriate selinux context on it.

dmalcolm might not have liked that idea because of all the visible changes it would have to do (configuring the directories to search). Or it might just have been too much time to expend. I'm not sure.

btw, the workaround is to set httpd_tmp_exec --> on

-Toshio

On Fri, Apr 20, 2012 at 12:16:34PM -0400, Adam Young wrote:

On 04/20/2012 10:47 AM, Toshio Kuratomi wrote:

On Fri, Apr 20, 2012 at 09:42:26AM -0400, Adam Young wrote:

    One caveat.   Any DJango app (Probably most Python wsgi apps, actually) is
    going to give an AVC Denial warning upon startup.

Only a denial?  ;-)  Do you have selinux in permissive?

In enforcing it still gives a denial....

    DJango imports Python's UUID
    module which in turn imports ctypes.  Ctypes does dynamic code generation,
    specifically by writing a file andd then trying to execute it, which, as you
    can imagine,  is a pretty big security hole.  Let the wsgi community know that,
    until we have that fixed,  we should not attempt to get rid of the AVC denial
    warning message, but instead should push on the Python upstread to get a fix
    in.  Yes, David Malcolm is aware of it.

    https://bugzilla.redhat.com/show_bug.cgi?id=814391


That's sorta a duplicate of this bug;
https://bugzilla.redhat.com/show_bug.cgi?id=582009

(AFAICS, they're the same, but yours is against RHEL and mine is against
Fedora).

Yes, they are the same, but mine has to do with the fact that it is part of the core library calling into ctypes. They can be addressed and fixed separately.

Upstream python doesn't like ctypes because it allows python code to more easily create obscure bugs but it likes it more than the alternatives. The reason is that upstream python is very friendly to the alternate language vms/interpreters. Those alternatives often can't work with the python C-API/ABI. But they can work with ctypes.

I discussed it with dmalcolm when I opened it in 2010 -- it's not easily
solvable.

* By its nature, libffi needs to generate code that it then executes.

I think this is the crux of the matter. I do not think that libffi needs to write this code out to disk to read it back in. It would be better if it held it in memory, but even that would probably be disallowed by SELinux. I suspect that there are better ways to do this form of dynamic binding that does not require code generation.

The previous python maintainer actually wrote the patch to have it write out to disk because we have SELinux set to prevent execmem by default. Writing to disk is "better" in that it allows noexecmem by default on Fedora.

However, for libraries shipped with Fedora, there should be no need to use ctypes.

If you're talking about changing uuid into an extension module, then see above as to why that isn't an upstreamable change.

-Toshio

Hello,

I noticed that Django-1.3 has spent 14 days in the testing branch as of yesterday - do you plan to release it now, or does additional testing need to be done on it?

Thanks,

Adam Bishop Access & Identity Management Janet Direct line: +44 (0)1235 822 245 Janet, the UK’s education and research network

On 20 Apr 2012, at 19:25, David Malcolm wrote:

On Fri, 2012-04-20 at 09:37 -0700, Toshio Kuratomi wrote:

...

On Fri, Apr 20, 2012 at 12:16:34PM -0400, Adam Young wrote:

...

On 04/20/2012 10:47 AM, Toshio Kuratomi wrote:

On Fri, Apr 20, 2012 at 09:42:26AM -0400, Adam Young wrote:

   One caveat.   Any DJango app (Probably most Python wsgi apps, actually) is
   going to give an AVC Denial warning upon startup.

Only a denial? ;-) Do you have selinux in permissive?

In enforcing it still gives a denial.... DJango imports Python's UUID module which in turn imports ctypes. Ctypes does dynamic code generation, specifically by writing a file andd then trying to execute it, which, as you can imagine, is a pretty big security hole. Let the wsgi community know that, until we have that fixed, we should not attempt to get rid of the AVC denial warning message, but instead should push on the Python upstread to get a fix in. Yes, David Malcolm is aware of it.

   https://bugzilla.redhat.com/show_bug.cgi?id=814391

That's sorta a duplicate of this bug; https://bugzilla.redhat.com/show_bug.cgi?id=582009

(AFAICS, they're the same, but yours is against RHEL and mine is against Fedora).

Yes, they are the same, but mine has to do with the fact that it is part of the core library calling into ctypes. They can be addressed and fixed separately.

Upstream python doesn't like ctypes because it allows python code to more easily create obscure bugs but it likes it more than the alternatives. The reason is that upstream python is very friendly to the alternate language vms/interpreters. Those alternatives often can't work with the python C-API/ABI. But they can work with ctypes.

...

I discussed it with dmalcolm when I opened it in 2010 -- it's not easily solvable.

• By its nature, libffi needs to generate code that it then executes.

I think this is the crux of the matter. I do not think that libffi needs to write this code out to disk to read it back in. It would be better if it held it in memory, but even that would probably be disallowed by SELinux. I suspect that there are better ways to do this form of dynamic binding that does not require code generation.

The previous python maintainer actually wrote the patch to have it write out to disk because we have SELinux set to prevent execmem by default. Writing to disk is "better" in that it allows noexecmem by default on Fedora.

...

However, for libraries shipped with Fedora, there should be no need to use ctypes.

If you're talking about changing uuid into an extension module, then see above as to why that isn't an upstreamable change.

It may be possible to fix the issue with uuid with a one-line change to ctypes which makes it avoid the SELinux-unfriendly codepaths unless absolutely necessary (uuid doesn't use them): see https://bugzilla.redhat.com/show_bug.cgi?id=814391#c2

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