Re: [PATCH 3/3] read_config: skip file/directory with unsecure permissions

[Yann Droneaud <ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>]

Hi,

Le mercredi 22 mai 2013 à 14:32 -0700, Roland Dreier a écrit :
> On Mon, May 20, 2013 at 2:43 PM, Yann Droneaud <ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org> wrote:
> > libibverbs must refuse to load arbitrary shared objects.
> >
> > This patch check the configuration directory and files for
> > - being owned by root;
> > - not being writable by others.
> 
> uverbs is an unprivileged interface.  Right now I can develop and test
> libibverbs and driver code as an unprivileged user.  If I'm
> understanding correctly, this patch would break that -- I'd have to
> install to a root-owned directory to test.
> 

I've missed this use case.
Indeed user should be able to use his own version of libibverbs and
configuration files.

> What's the exploit this protects against?

The configuration mechanism allow loading arbitrary shared object: this
should be done with care when running setuid binaries / running program
as root.

Adding some basic sanity check is welcome to protect from someone
tampering the configuration files.

I'm going to post an updated patchset which will secure (in-depth)
access to configuration files while allowing user to use their own
files.

Regards.

-- 
Yann Droneaud
OPTEYA

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