From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: [PATCH] netfilter: xt_recent: don't reject rule if new hitcount exceeds table max Date: Fri, 13 Feb 2015 12:47:50 +0100 Message-ID: <1423828070-10667-1-git-send-email-fw@strlen.de> Cc: chris@cvine.freeserve.co.uk, Florian Westphal To: Return-path: Received: from Chamillionaire.breakpoint.cc ([80.244.247.6]:47742 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752328AbbBMNJo (ORCPT ); Fri, 13 Feb 2015 08:09:44 -0500 Sender: netfilter-devel-owner@vger.kernel.org List-ID: given: -A INPUT -m recent --update --seconds 30 --hitcount 4 and iptables-save > foo then iptables-restore < foo will fail with: kernel: xt_recent: hitcount (4) is larger than packets to be remembered (4) for table DEFAULT Even when the check is fixed, the restore won't work if the hitcount is increased to e.g. 6, since by the time checkentry runs it will find the 'old' incarnation of the table. We can avoid this by increasing the maximum threshold silently; we only have to rm all the current entries of the table (these entries would not have enough room to handle the increased hitcount). This even makes (not-very-useful) -A INPUT -m recent --update --seconds 30 --hitcount 4 -A INPUT -m recent --update --seconds 30 --hitcount 42 work. Fixes: abc86d0f99242b7f142b (netfilter: xt_recent: relax ip_pkt_list_tot restrictions) Tracked-down-by: Chris Vine Signed-off-by: Florian Westphal --- net/netfilter/xt_recent.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index 30dbe34..45e1b30 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -378,12 +378,11 @@ static int recent_mt_check(const struct xt_mtchk_param *par, mutex_lock(&recent_mutex); t = recent_table_lookup(recent_net, info->name); if (t != NULL) { - if (info->hit_count > t->nstamps_max_mask) { - pr_info("hitcount (%u) is larger than packets to be remembered (%u) for table %s\n", - info->hit_count, t->nstamps_max_mask + 1, - info->name); - ret = -EINVAL; - goto out; + if (nstamp_mask > t->nstamps_max_mask) { + spin_lock_bh(&recent_lock); + recent_table_flush(t); + t->nstamps_max_mask = nstamp_mask; + spin_unlock_bh(&recent_lock); } t->refcnt++; -- 2.0.5