Messages in this thread | | | From | Paul Moore <> | Subject | Re: ANN: libseccomp | Date | Mon, 09 Apr 2012 18:46:02 -0400 |
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On Monday, April 09, 2012 04:51:30 PM Will Drewry wrote: > On Mon, Apr 9, 2012 at 4:32 PM, Paul Moore <paul@paul-moore.com> wrote: > > On Monday, April 09, 2012 12:16:30 PM Kees Cook wrote: > >> On Mon, Apr 9, 2012 at 11:58 AM, Paul Moore <paul@paul-moore.com> wrote: > >> > With the seccomp patches finally stabilizing a bit, it seems like now > >> > is a > >> > good time to announce libseccomp: a library designed to make it easier > >> > to > >> > create complex, architecture independent seccomp filters. > >> > > >> > * http://sourceforge.net/projects/libseccomp/ > >> > * git clone git://git.code.sf.net/p/libseccomp/libseccomp > >> > >> This looks really great; nice work! > > Agreed -- this is great to see!
Not as much as the actual kernel support :)
> >> I see that the arch check happens during _gen_bpf_build_bpf(), which > >> is excellent. Do you have any thoughts about including a call to > >> prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) by default as well? > > > > That is a good question, and I guess it comes down to another question of > > if anyone would want to use seccomp without NO_NEW_PRIVS. If the answer > > is no then I'm comfortable adding it into the seccomp_load() function; > > however, if the answer is yes we might want to do something different. > > > > I haven't given much thought to this yet, so if you or anyone else feels > > strongly about the issue - either pro or con - I'd appreciate hearing the > > argument. > > I guess the question is if there is an expectation that this library > be used with something like lxc, where a whole, functional system with > suid/fcaps binaries is contained. In that world, it may not be > desirable to set the nnp bit. The same is true if, for some reason, > the init task was to set a system-wide filter. > > Most likely, default use of nnp is probably "the right thing", but > it'd be nice to be able to annotate when you really want to allow > privileged contexts to set filters without nnp.
Okay, that seems reasonable: default to NO_NEW_PRIVS, but provide an override mechanism.
I've been wanting a mechanism/API for tweaking some of the default library parameters for the past few weeks, this is likely the last bit of motivation I need to start working on this. I'll look into it once the license issue is sorted.
-- paul moore www.paul-moore.com
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