Re: xt_recent broken in kernel 3.19.0 + PATCH

On Thu, 12 Feb 2015 10:26:16 +0000
Chris Vine [off-list ref] wrote:

On Thu, 12 Feb 2015 09:35:33 +0100
Florian Westphal [off-list ref] wrote:

quoted

Cong Wang [off-list ref] wrote:

quoted

(Cc'ing netdev and netfilter-devel lists)

Thanks for forwarding.

quoted

quoted

Chris Vine [off-list ref] wrote:

quoted

  iptables -D SSH_CHAIN -m conntrack --ctstate NEW \
    -m recent --update --seconds $SSH_LOGIN_PERIOD --hitcount
$SSH_TRIES -j DROP

--- linux-3.19.0/net/netfilter/xt_recent.c~     2015-02-10

09:18:44.657376355 +0000 +++
linux-3.19.0/net/netfilter/xt_recent.c      2015-02-11
17:58:33.311608835 +0000 @@ -378,7 +378,7 @@
mutex_lock(&recent_mutex); t = recent_table_lookup(recent_net,
info->name); if (t != NULL) {
-               if (info->hit_count > t->nstamps_max_mask) {
+               if (info->hit_count > t->nstamps_max_mask + 1) {

Looks good. Chris, could you formally submit this patch to
netfilter-devel@vger.kernel.org?

Thanks!

Done.

On further testing I see that that patch only solves the problem if
SSH_TRIES is set to a power of two boundary.  You still get an error
loading the rule if it is anything else.  I think there is something
wrong with the nstamp_mask heuristic which is used here.

Chris