MD5 is broken sometimes, an option to use SHA would be appreciated.

[pol@…]

Machine Info:
Debian Linux 2.4.26-1-386
mod_python 3.1
Apache2
Python 2.3

Description:
Apparently my version of mod_python is not generating md5 strings well. As a result, the session was throwing a "Suspicious Operation" exception when checking for cookie tampering. I am not the first person that this has happened to.

The follwing fixed the problem:
Modify contrib/sessions/models.py and contrib/admin/views/decorators.py

• Import sha and change *md5* to *sha*
• Change encoded_data[:-32], encoded_data[-32:] to encoded_data[:-40], encoded_data[-40:]

Suggestion:
Add a SESSION_KEY_TYPE var to settings.py that allows the user to specify md5 or sha session keys.

[nikl@…]

the topic has been brought up on the mailinglists, e.g.:

​http://groups.google.com/group/django-users/browse_thread/thread/360d5b76ea2c614a/9e36f023614f8baf
​http://groups.google.com/group/django-users/browse_thread/thread/eeb44c894342d6f7/4b951b6d3a8644dd
​http://modpython.org/pipermail/mod_python/2006-June/021482.html

I'd like to propose that the hashing algorithm should be put somewhere else with the possibility to set the preferred hashing algorithm generally - since this is used in this several situations (sessions, postdata, comments,..). possibly something along the lines of the attached patch?

[nikl@…]

svn diff of the changed files

[nikl@…]

i had put this is in django/utils/hashes.py

[nikl@…]

for anybody who's also experiencing this problem, Alain Tesio mentioned
another odd factor and its workaround on the modpy-mailinglist:

​http://modpython.org/pipermail/mod_python/2006-July/021544.html

[Paul Egges]

I had the same problem, and a similar solution, instead of dumping the md5 I just test to see if it is working properly by

if (md5.new('testencrypt').hexdigest()!='17500f56515d37cd65a68aca1b4679a6')

If it fails then I use sha, if it passes I use md5.

[Chris Beaven]

From nikl's comment, this looks like it's caused by another library being installed: libmhash2, not a Django problem.

Still, if it's a problem then perhaps we should have a work around?

[James Bennett]

Since this appears to be caused by a third-party library breaking things that are out of our control, I'm going to mark invalid.