linux-kernel - Re: [PATCH 6/7] user namespaces: convert all capable checks in kernel/sys.c

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20110110225642.GB18944@localhost>
Date:	Mon, 10 Jan 2011 16:56:42 -0600
From:	Serge Hallyn <serge.hallyn@...onical.com>
To:	Bastian Blank <bastian@...di.eu.org>,
	"Serge E. Hallyn" <serge@...lyn.com>,
	containers@...ts.linux-foundation.org,
	kernel list <linux-kernel@...r.kernel.org>,
	LSM <linux-security-module@...r.kernel.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Kees Cook <kees.cook@...onical.com>,
	Alexey Dobriyan <adobriyan@...il.com>,
	Michael Kerrisk <mtk.manpages@...il.com>
Subject: Re: [PATCH 6/7] user namespaces: convert all capable checks in
 kernel/sys.c

Quoting Bastian Blank (bastian@...di.eu.org):
> On Mon, Jan 10, 2011 at 09:14:07PM +0000, Serge E. Hallyn wrote:
> > -	if (pcred->uid  != cred->euid &&
> > -	    pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
> > +	if (pcred->user->user_ns != cred->user->user_ns &&
> > +	    pcred->uid  != cred->euid &&
> > +	    pcred->euid != cred->euid &&
> > +	    !ns_capable(pcred->user->user_ns, CAP_SYS_NICE)) {
> 
> I don't think this is correct. This would not error out if the both
> userns are the same. Because the same patern (check uid if same userns,
> otherwise only capability) shows up in several parts of the code, maybe
> this should be factored out.

Yes, I'm really not sure what I was thinking here.  Thanks!

> > @@ -496,7 +498,7 @@ SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
> >  	if (rgid != (gid_t) -1) {
> >  		if (old->gid == rgid ||
> >  		    old->egid == rgid ||
> > -		    capable(CAP_SETGID))
> > +		    ns_capable(current_user_ns(), CAP_SETGID))
> 
> Would it not possible to add another function (nsown_capable?) that
> checks against the own userns?

Good idea, I'll add that one.

thanks,
-serge
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/