From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liping Zhang Subject: [PATCH nf V3] netfilter: nf_ct_helper: permit cthelpers with different names via nfnetlink Date: Sat, 15 Apr 2017 19:27:42 +0800 Message-ID: <1492255662-57602-1-git-send-email-zlpnobody@163.com> Cc: netfilter-devel@vger.kernel.org, Liping Zhang To: pablo@netfilter.org Return-path: Received: from m12-16.163.com ([220.181.12.16]:58568 "EHLO m12-16.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752497AbdDOL2T (ORCPT ); Sat, 15 Apr 2017 07:28:19 -0400 Sender: netfilter-devel-owner@vger.kernel.org List-ID: From: Liping Zhang cthelpers added via nfnetlink may have the same tuple, i.e. except for the l3proto and l4proto, other fields are all zero. So even with the different names, we will also fail to add them: # nfct helper add ssdp inet udp # nfct helper add tftp inet udp nfct v1.4.3: netlink error: File exists So in order to avoid unpredictable behaviour, we should: 1. cthelpers can be selected by nft ct helper obj or xt_CT target, so report error if duplicated { name, l3proto, l4proto } tuple exist. 2. cthelpers can be selected by nf_ct_tuple_src_mask_cmp when nf_ct_auto_assign_helper is enabled, so also report error if duplicated { l3proto, l4proto, src-port } tuple exist. Also note, if the cthelper is added from userspace, then the src-port will always be zero, it's invalid for nf_ct_auto_assign_helper, so there's no need to check the second point listed above. Fixes: 893e093c786c ("netfilter: nf_ct_helper: bail out on duplicated helpers") Signed-off-by: Liping Zhang --- V3: no changes, rebase on nf.git and resubmit V2: drop to use __nf_conntrack_helper_find, per Pablo net/netfilter/nf_conntrack_helper.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c index 4eeb341..99bcd44 100644 --- a/net/netfilter/nf_conntrack_helper.c +++ b/net/netfilter/nf_conntrack_helper.c @@ -386,17 +386,33 @@ int nf_conntrack_helper_register(struct nf_conntrack_helper *me) struct nf_conntrack_tuple_mask mask = { .src.u.all = htons(0xFFFF) }; unsigned int h = helper_hash(&me->tuple); struct nf_conntrack_helper *cur; - int ret = 0; + int ret = 0, i; BUG_ON(me->expect_policy == NULL); BUG_ON(me->expect_class_max >= NF_CT_MAX_EXPECT_CLASSES); BUG_ON(strlen(me->name) > NF_CT_HELPER_NAME_LEN - 1); mutex_lock(&nf_ct_helper_mutex); - hlist_for_each_entry(cur, &nf_ct_helper_hash[h], hnode) { - if (nf_ct_tuple_src_mask_cmp(&cur->tuple, &me->tuple, &mask)) { - ret = -EEXIST; - goto out; + for (i = 0; i < nf_ct_helper_hsize; i++) { + hlist_for_each_entry(cur, &nf_ct_helper_hash[i], hnode) { + if (!strcmp(cur->name, me->name) && + (cur->tuple.src.l3num == NFPROTO_UNSPEC || + cur->tuple.src.l3num == me->tuple.src.l3num) && + cur->tuple.dst.protonum == me->tuple.dst.protonum) { + ret = -EEXIST; + goto out; + } + } + } + + /* avoid unpredictable behaviour for auto_assign_helper */ + if (!(me->flags & NF_CT_HELPER_F_USERSPACE)) { + hlist_for_each_entry(cur, &nf_ct_helper_hash[h], hnode) { + if (nf_ct_tuple_src_mask_cmp(&cur->tuple, &me->tuple, + &mask)) { + ret = -EEXIST; + goto out; + } } } hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]); -- 2.5.5