Re: [Xenomai-help] Xenomai and capabilities

[Jan Kiszka <jan.kiszka@domain.hid>]

Am 11.10.2010 18:11, Anders Blomdell wrote:
> We are planning to extend our use of xenomai to a wider audience at our
> department, and therefore I would like to know which is the better way to let
> users run xenomai programs with a minimum of system privileges, the
> possibilities I can see are:
> 
> 1. Let the user run anything as root; simple but obviously a security nightmare.
> 2. Write a suid program that let's its children inherit the right capabilities
> and then does a seteuid and does an execve; unfortunately this implies that the
> program that is execve'd has the right capabilties set [which has to be done by
> the suid program as well], and this can only be done on filesystems that can
> have extended attributes (i.e. no FAT, NFS, etc).
> 3. Write a suid program that drops all unneeded privileges and then use dlopen
> and friends to execute the user code.
> 
> I guess that there exists better ways, so somebody please enlighten me.
> 

A bit better, but not perfect:

http://www.xenomai.org/index.php/Non-root_RT

Combining this with mediated hardware access (robust drivers) and
enabling the Xenomai watchdog should provide a reasonably safe&secure
environment.

Jan


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