netdev - Re: [PATCH bpf] bpf: Support sk lookup in netns with id 0

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] [day] [month] [year] [list]

Date:   Wed, 28 Nov 2018 11:24:24 -0800
From:   Joe Stringer <joe@...d.net.nz>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     Joe Stringer <joe@...d.net.nz>,
        Nicolas Dichtel <nicolas.dichtel@...nd.com>,
        David Ahern <dsahern@...il.com>, daniel@...earbox.net,
        ast@...nel.org, netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH bpf] bpf: Support sk lookup in netns with id 0

On Tue, 27 Nov 2018 at 13:12, Alexei Starovoitov
<alexei.starovoitov@...il.com> wrote:
>
> On Tue, Nov 27, 2018 at 10:01:40AM -0800, Joe Stringer wrote:
> > On Tue, 27 Nov 2018 at 06:49, Nicolas Dichtel <nicolas.dichtel@...nd.com> wrote:
> > >
> > > Le 26/11/2018 ą 23:08, David Ahern a écrit :
> > > > On 11/26/18 2:27 PM, Joe Stringer wrote:
> > > >> @@ -2405,6 +2407,9 @@ enum bpf_func_id {
> > > >>  /* BPF_FUNC_perf_event_output for sk_buff input context. */
> > > >>  #define BPF_F_CTXLEN_MASK           (0xfffffULL << 32)
> > > >>
> > > >> +/* BPF_FUNC_sk_lookup_tcp and BPF_FUNC_sk_lookup_udp flags. */
> > > >> +#define BPF_F_SK_CURRENT_NS         0x80000000 /* For netns field */
> > > >> +
> > > >
> > > > I went down the nsid road because it will be needed for other use cases
> > > > (e.g., device lookups), and we should have a general API for network
> > > > namespaces. Given that, I think the _SK should be dropped from the name.
> >
> > Fair point, I'll drop _SK from the name
> >
> > > >
> > > Would it not be possible to have a s32 instead of an u32 for the coming APIs?
> > > It would be better to match the current netlink and kernel APIs.
> >
> > Sure, I'll look into this.
> >
> > I had earlier considered whether it's worth attempting to leave the
> > upper 32 bits of this parameter open for potential future expansion,
> > but at this point I'm not taking that into consideration. If anyone
> > has preferences or thoughts on that I'd be interested to hear them.
>
> Can we keep u64 as an argument type and do
> if ((s32)netns_id < 0) {
>   net = caller_net;
> } else {
>   if (netns_id > S32_MAX)
>     goto err;
>   net = get_net_ns_by_id(caller_net, netns_id);
> }
>
> No need for extra macro in such case and passing -1 would match the rest of the kernel.
> Upper 32-bit would still be open for future expansion.

Sounds good.