From bcf4934288402be3464110109a4dae3bd6fb3e93 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Tue, 12 Apr 2016 01:31:14 +0200 Subject: [PATCH] netfilter: ebtables: Fix extension lookup with identical name 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 8570bc7744c2..5a61f35412a0 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;