Some questions about /dev/twe* and selinux context

[Ken YANG]

Ali Nebi wrote:
> Hi all,
> 
> i have some problems with selinux context about /dev/twe*
> 
> I get these messages: 
> 
> Aug 28 08:41:19 w3host kernel: audit(1188283279.352:167): avc:  denied
> { getattr } for  pid=2512 comm="smartd" name="twe0" dev=tmpfs ino=10268
> scontext=system_u:system_r:fsdaem
> on_t:s0 tcontext=system_u:object_r:device_t:s0 tclass=chr_file
> Aug 28 08:41:19 w3host kernel: audit(1188283279.388:168): avc:  denied
> { read } for  pid=2512 comm="smartd" name="twe0" dev=tmpfs ino=10268
> scontext=system_u:system_r:fsdaemon_
> t:s0 tcontext=system_u:object_r:device_t:s0 tclass=chr_file
> Aug 28 08:41:19 w3host kernel: audit(1188283279.445:169): avc:  denied
> { ioctl } for  pid=2512 comm="smartd" name="twe0" dev=tmpfs ino=10268
> scontext=system_u:system_r:fsdaemon
> _t:s0 tcontext=system_u:object_r:device_t:s0 tclass=chr_file
> 
> I know that /dev/twe* must have fixed_disk_device_t context.
> 
> When i fix it with chcon -t fixed_disk_device_t /dev/twe* the avc stop
> to audit for this. Everything works ok. When i restarted the system, the
> context changed to device_t again. I wrote in rc.local the command to
> change cotentext, but it returned me "no such file or directory". I know
> that twe* devices are created automatically on boot, so let's say that
> this is no problem. I decided to use semanage to add rule for /dev/twe*
> like this:
> /usr/sbin/semanage fcontext -a -f -c -t fixed_disk_device_t "/dev/twe*"
> 
> After reboot, the result was the same, the context is device_t :( 
> When i used restorecon command:
> /sbin/restorecon /dev/twe* 
> it changed the context to fixed_disk_device_t
> 
> So the questions are:
> 
> 1. Where i make mistake

i have not these device files, but as you said, they are created
automatically, so the content of file_contexts is useless in
this situation, except that the program restorecon after creation

> 2. What can i do to fix this problem ? 

two methods, one is modify the program as what i mentioned above.
vmware had similar problems, which can resolved by modifying
net-service.sh.

another method is to write policy, using Transition-based rules,
so the files will be labeled rightly after creating. IIRC, "/dev"
is tmpfs_t, so you should use Transition-based

> 
> Regards, Ali Nebi!
> 
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