On 26 June 2019 19:18:35 EEST, Eyal Birger [off-list ref] wrote:

Hi Nik,

On Wed, 26 Jun 2019 18:56:14 +0300
Nikolay Aleksandrov [off-list ref] wrote:

quoted

For NFPROTO_UNSPEC xt_matches there's no way to restrict the matching
to a specific family, in order to do so we record the user-specified
family and later enforce it while doing the match.

v2: adjust changes to missing patch, was patch 04 in v1

Signed-off-by: Nikolay Aleksandrov <redacted>
---
 net/sched/em_ipt.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

..snip..

quoted

@@ -182,8 +195,8 @@ static int em_ipt_match(struct sk_buff *skb,

struct tcf_ematch *em, const struct em_ipt_match *im = (const void
*)em->data; struct xt_action_param acpar = {};
 	struct net_device *indev = NULL;
-	u8 nfproto = im->match->family;
 	struct nf_hook_state state;
+	u8 nfproto = im->nfproto;

Maybe I'm missing something now - but it's not really clear to me now
why keeping im->nfproto would be useful:

If NFPROTO_UNSPEC was provided by userspace then the actual nfproto
used
will be taken from the packet, and if NFPROTO_IPV4/IPV6 was specified
from userspace then it will equal im->match->family.

Is there any case where the resulting nfproto would differ as a result
of this patch?

Otherwise the patchset looks excellent to me.

Thanks!
Eyal.

Hi,
It's needed to limit the match only to the user-specified family
for unspec xt matches. The problem is otherwise im->match->family
stays at nfproto_unspec regardless of the user choice.

Thanks for reviewing the set. 

Cheers,
  Nik