Writing Files with Django Under SELinux

Abstract
Playing about with Django’s excellent admin interface this morning I came across a little problem that I am sure others will find if using Django in an SELinux environment. This concerns the ability to upload files to a server – in my case using Apache, mod_wsgi (not in daemon mode), and Fedora 10 with SELinux running.

Method
I was getting a [Errno 13] Permission denied error when trying to upload a file – pretty obvious that the server wasn’t happy about something there then. First of all I decided to check and see which user Apache was running – a convenient way to do this is to use the top command. Once in there, type u followed by apache (the apache process owner in my case) and this exposes only running processes by apache.

top - 12:33:00 up 24 min,  1 user,  load average: 0.00, 0.00, 0.00
Tasks:  93 total,   1 running,  92 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0%us,  0.3%sy,  0.0%ni, 99.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:    254128k total,   139884k used,   114244k free,     5536k buffers
Swap:   524280k total,        0k used,   524280k free,    51376k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 1870 apache    20   0 38604  16m 4664 S  0.0  6.6   0:00.53 httpd
 ...

That was fine then – next to check the directory I was trying to upload files to:

[user@lapwing media]$ ls -l
drwxr--r-- 2 apache apache    4096 2009-05-22 12:16 images

Also looked ok – one last thing to check…
SELinux…
Yes, the old SELinux chestnut again… I solved this by changing the directory SELinux context:

[root@lapwing media]# chcon -t tmp_t images

Then check

[root@lapwing media]# ls -dZ images/
drwxr--r--  apache apache system_u:object_r:tmp_t:s0       images/

Tried the upload again – this time it worked.