linux-kernel - Re: [PATCH 9/9] make net/core/scm.c uid comparisons user namespace aware

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Date:	Tue, 18 Oct 2011 23:22:42 +0000
From:	"Serge E. Hallyn" <serge@...lyn.com>
To:	Joe Perches <joe@...ches.com>
Cc:	linux-kernel@...r.kernel.org, ebiederm@...ssion.com,
	akpm@...ux-foundation.org, oleg@...hat.com, richard@....at,
	mikevs@...all.net, segoon@...nwall.com, gregkh@...e.de,
	dhowells@...hat.com, eparis@...hat.com,
	"Serge E. Hallyn" <serge.hallyn@...onical.com>,
	netdev@...r.kernel.org
Subject: Re: [PATCH 9/9] make net/core/scm.c uid comparisons user namespace
 aware

Quoting Joe Perches (joe@...ches.com):
> On Tue, 2011-10-18 at 21:54 +0000, Serge Hallyn wrote:
> > From: "Serge E. Hallyn" <serge.hallyn@...onical.com>
> 
> Hi Serge.
> 
> Just some trivial style notes.
> 
> > Currently uids are compared without regard for the user namespace.
> > Fix that to prevent tasks in a different user namespace from
> > wrongly matching on SCM_CREDENTIALS.
> []
> > diff --git a/net/core/scm.c b/net/core/scm.c
> 
> > -static __inline__ int scm_check_creds(struct ucred *creds)
> > +static __inline__ bool uidequiv(const struct cred *src, struct ucred *tgt,
> > +			       struct user_namespace *ns)
> 
> Perhaps inline is better than __inline__ and do these
> functions really need to be marked inline at all?

Dunno, I was just sticking with the current style.

> > +{
> > +	if (src->user_ns != ns)
> > +		goto check_capable;
> > +	if (src->uid == tgt->uid || src->euid == tgt->uid ||
> > +	    src->suid == tgt->uid)
> 
> Perhaps this is less prone to typo errors and are a bit
> more readable as:
> 
> 	if (tgt->uid == src->uid ||
> 	    tgt->uid == src->euid ||
> 	    tgt->uid == src->suid)

I do like that better.

thanks,
-serge
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