Re: [libseccomp-discuss] ANN: libseccomp

[Paul M. <pa...@pa...>]

On Friday, April 13, 2012 11:47:08 PM Henrique de Moraes Holschuh wrote:
> On Fri, 13 Apr 2012, Paul Moore wrote:
> > the seccomp filter into the kernel.  By default libseccomp attempts to set
> > NO_NEW_PRIVS but does not fail if prctl(NO_NEW_PRIVS) returns with an
> > error;
>
> Isn't that dangerous in non-obvious ways, as in it can actually
> cause/activate/enable/open security issues on priviledged processes that
> don't expect whatever filtering seccomp will subject them to?

We could debate this point but it turns out it is a bit of a non-issue as the 
kernel code requires NO_NEW_PRIVS unless CAP_SYS_ADMIN is set; if neither 
conditions are true the seccomp filter with fail (check Will's patches).

If prctl(NO_NEW_PRIVS) fails the error is always returned, and the 
attribute/boolean to disable this functionality has been removed since it 
likely serves little purpose.

> Defaults are important, as they're what people _who don't know any better_
> are likely to use.

Agreed.  You'll never hear me argue otherwise.

-- 
paul moore
www.paul-moore.com