Re: [PATCH iptables] libxt_cgroup2: add support for cgroup2 path matching

From: Tejun Heo
Date: Tue Nov 17 2015 - 18:10:03 EST


Hello,

On Wed, Nov 18, 2015 at 12:02:01AM +0100, Jan Engelhardt wrote:
> On Tuesday 2015-11-17 20:42, Tejun Heo wrote:
> >+static void cgroup2_save(const void *ip, const struct xt_entry_match *match)
> >+{
> >+ const struct xt_cgroup2_info *info = (void *)match->data;
> >+
> >+ printf("%s --path %s", info->invert ? " !" : "", info->path);
> >+}
>
> Can cgroup path names contain anything fancy, like spaces, backslashes, etc.?
> If so, xtables_save_string() will be needed here.

Will update.

> >+static struct xtables_match cgroup2_match = {
> >+ .family = NFPROTO_UNSPEC,
> >+ .name = "cgroup2",
> >+ .version = XTABLES_VERSION,
> >+ .size = XT_ALIGN(sizeof(struct xt_cgroup2_info)),
> >+ .userspacesize = XT_ALIGN(sizeof(struct xt_cgroup2_info)),
>
> userspacesize must not include xt_cgroup2_info.priv.
> Change to offsetof(...), cf. other .c modules which do this.

Ah, okay.

...
> >+\fBIMPORTANT\fP: when being used in the INPUT chain, the cgroup2
> >+matcher is currently only of limited functionality, meaning it
> >+will only match on packets that are processed for local sockets
> >+through early socket demuxing. Therefore, general usage on the
> >+INPUT chain is disadviced unless the implications are well
>
> is disadviced (sic) -> is not advised

Will update. That's copied verbatim from xt_cgroup tho. Will create
a patch to update that too.

Thanks.

--
tejun
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