From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH 3/3] netfilter: ebtables: Fix extension lookup with identical name Date: Thu, 14 Apr 2016 00:54:54 +0200 Message-ID: <1460588094-3933-4-git-send-email-pablo@netfilter.org> References: <1460588094-3933-1-git-send-email-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: In-Reply-To: <1460588094-3933-1-git-send-email-pablo@netfilter.org> Sender: netfilter-devel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Phil Sutter If a requested extension exists as module and is not loaded, ebt_check_match() might accidentally use an NFPROTO_UNSPEC one with same name and fail. Reproduced with limit match: Given xt_limit and ebt_limit both built as module, the following would fail: modprobe xt_limit ebtables -I INPUT --limit 1/s -j ACCEPT The fix is to make ebt_check_match() distrust a found NFPROTO_UNSPEC extension and retry after requesting an appropriate module. Cc: Florian Westphal Signed-off-by: Phil Sutter Acked-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebtables.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 8570bc7..5a61f35 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -370,7 +370,11 @@ ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par, left - sizeof(struct ebt_entry_match) < m->match_size) return -EINVAL; - match = xt_request_find_match(NFPROTO_BRIDGE, m->u.name, 0); + match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0); + if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) { + request_module("ebt_%s", m->u.name); + match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0); + } if (IS_ERR(match)) return PTR_ERR(match); m->u.match = match; -- 2.1.4