netdev - Re: [PATCH net-next v2 2/2] bpf: Remove the capability check for cgroup skb eBPF program

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Message-ID: <20170602015815.u4lecyfap6l6lenr@ast-mbp>
Date:   Thu, 1 Jun 2017 18:58:17 -0700
From:   Alexei Starovoitov <alexei.starovoitov@...il.com>
To:     Chenbo Feng <fengc@...gle.com>
Cc:     Chenbo Feng <chenbofeng.kernel@...il.com>, netdev@...r.kernel.org,
        David Miller <davem@...emloft.net>,
        Lorenzo Colitti <lorenzo@...gle.com>
Subject: Re: [PATCH net-next v2 2/2] bpf: Remove the capability check for
 cgroup skb eBPF program

On Thu, Jun 01, 2017 at 06:55:09PM -0700, Chenbo Feng wrote:
> On Thu, Jun 1, 2017 at 4:42 PM, Alexei Starovoitov <
> alexei.starovoitov@...il.com> wrote:
> 
> > On Wed, May 31, 2017 at 06:16:00PM -0700, Chenbo Feng wrote:
> > > From: Chenbo Feng <fengc@...gle.com>
> > >
> > > Currently loading a cgroup skb eBPF program require a CAP_SYS_ADMIN
> > > capability while attaching the program to a cgroup only requires the
> > > user have CAP_NET_ADMIN privilege. We can escape the capability
> > > check when load the program just like socket filter program to make
> > > the capability requirement consistent.
> > >
> > > Change since v1:
> > > Change the code style in order to be compliant with checkpatch.pl
> > > preference
> > >
> > > Signed-off-by: Chenbo Feng <fengc@...gle.com>
> >
> > as far as I can see they're indeed the same as socket filters, so
> > Acked-by: Alexei Starovoitov <ast@...nel.org>
> >
> > but I don't quite understand how it helps, since as you said
> > attaching such unpriv fd to cgroup still requires root.
> > Do you have more patches to follow?
> >
> > Actually not, the purpose of this patch is only to make sure if a program
> have
> CAP_NET_ADMIN but not CAP_SYS_ADMIN it can still load and attach eBPF
> programs to cgroup.

got it. Thanks