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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 3/9] openvswitch: call only into reachable nf-nat code
Date: Mon, 28 Mar 2016 19:57:56 +0200
Message-ID: <1459187882-5357-4-git-send-email-pablo@netfilter.org> (raw)
In-Reply-To: <1459187882-5357-1-git-send-email-pablo@netfilter.org>

From: Arnd Bergmann <arnd@arndb.de>

The openvswitch code has gained support for calling into the
nf-nat-ipv4/ipv6 modules, however those can be loadable modules
in a configuration in which openvswitch is built-in, leading
to link errors:

net/built-in.o: In function `__ovs_ct_lookup':
:(.text+0x2cc2c8): undefined reference to `nf_nat_icmp_reply_translation'
:(.text+0x2cc66c): undefined reference to `nf_nat_icmpv6_reply_translation'

The dependency on (!NF_NAT || NF_NAT) prevents similar issues,
but NF_NAT is set to 'y' if any of the symbols selecting
it are built-in, but the link error happens when any of them
are modular.

A second issue is that even if CONFIG_NF_NAT_IPV6 is built-in,
CONFIG_NF_NAT_IPV4 might be completely disabled. This is unlikely
to be useful in practice, but the driver currently only handles
IPv6 being optional.

This patch improves the Kconfig dependency so that openvswitch
cannot be built-in if either of the two other symbols are set
to 'm', and it replaces the incorrect #ifdef in ovs_ct_nat_execute()
with two "if (IS_ENABLED())" checks that should catch all corner
cases also make the code more readable.

The same #ifdef exists ovs_ct_nat_to_attr(), where it does not
cause a link error, but for consistency I'm changing it the same
way.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 05752523e565 ("openvswitch: Interface with NAT.")
Acked-by: Joe Stringer <joe@ovn.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/openvswitch/Kconfig     |  4 +++-
 net/openvswitch/conntrack.c | 16 ++++++++--------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/net/openvswitch/Kconfig b/net/openvswitch/Kconfig
index 234a733..ce94729 100644
--- a/net/openvswitch/Kconfig
+++ b/net/openvswitch/Kconfig
@@ -7,7 +7,9 @@ config OPENVSWITCH
 	depends on INET
 	depends on !NF_CONNTRACK || \
 		   (NF_CONNTRACK && ((!NF_DEFRAG_IPV6 || NF_DEFRAG_IPV6) && \
-				     (!NF_NAT || NF_NAT)))
+				     (!NF_NAT || NF_NAT) && \
+				     (!NF_NAT_IPV4 || NF_NAT_IPV4) && \
+				     (!NF_NAT_IPV6 || NF_NAT_IPV6)))
 	select LIBCRC32C
 	select MPLS
 	select NET_MPLS_GSO
diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index 47f7c62..3797879 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -535,14 +535,15 @@ static int ovs_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
 	switch (ctinfo) {
 	case IP_CT_RELATED:
 	case IP_CT_RELATED_REPLY:
-		if (skb->protocol == htons(ETH_P_IP) &&
+		if (IS_ENABLED(CONFIG_NF_NAT_IPV4) &&
+		    skb->protocol == htons(ETH_P_IP) &&
 		    ip_hdr(skb)->protocol == IPPROTO_ICMP) {
 			if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
 							   hooknum))
 				err = NF_DROP;
 			goto push;
-#if IS_ENABLED(CONFIG_NF_NAT_IPV6)
-		} else if (skb->protocol == htons(ETH_P_IPV6)) {
+		} else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) &&
+			   skb->protocol == htons(ETH_P_IPV6)) {
 			__be16 frag_off;
 			u8 nexthdr = ipv6_hdr(skb)->nexthdr;
 			int hdrlen = ipv6_skip_exthdr(skb,
@@ -557,7 +558,6 @@ static int ovs_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
 					err = NF_DROP;
 				goto push;
 			}
-#endif
 		}
 		/* Non-ICMP, fall thru to initialize if needed. */
 	case IP_CT_NEW:
@@ -1239,7 +1239,8 @@ static bool ovs_ct_nat_to_attr(const struct ovs_conntrack_info *info,
 	}
 
 	if (info->range.flags & NF_NAT_RANGE_MAP_IPS) {
-		if (info->family == NFPROTO_IPV4) {
+		if (IS_ENABLED(CONFIG_NF_NAT_IPV4) &&
+		    info->family == NFPROTO_IPV4) {
 			if (nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MIN,
 					    info->range.min_addr.ip) ||
 			    (info->range.max_addr.ip
@@ -1247,8 +1248,8 @@ static bool ovs_ct_nat_to_attr(const struct ovs_conntrack_info *info,
 			     (nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MAX,
 					      info->range.max_addr.ip))))
 				return false;
-#if IS_ENABLED(CONFIG_NF_NAT_IPV6)
-		} else if (info->family == NFPROTO_IPV6) {
+		} else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) &&
+			   info->family == NFPROTO_IPV6) {
 			if (nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MIN,
 					     &info->range.min_addr.in6) ||
 			    (memcmp(&info->range.max_addr.in6,
@@ -1257,7 +1258,6 @@ static bool ovs_ct_nat_to_attr(const struct ovs_conntrack_info *info,
 			     (nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MAX,
 					       &info->range.max_addr.in6))))
 				return false;
-#endif
 		} else {
 			return false;
 		}
-- 
2.1.4

  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-28 17:57 [PATCH 0/9] Netfilter fixes for net Pablo Neira Ayuso
2016-03-28 17:57 ` [PATCH 1/9] netfilter: ipset: fix race condition in ipset save, swap and delete Pablo Neira Ayuso
2016-03-28 17:57 ` [PATCH 2/9] openvswitch: Fix checking for new expected connections Pablo Neira Ayuso
2016-03-28 17:57 ` Pablo Neira Ayuso [this message]
2016-03-28 17:57 ` [PATCH 4/9] netfilter: x_tables: validate e->target_offset early Pablo Neira Ayuso
2016-03-28 17:57 ` [PATCH 5/9] netfilter: x_tables: make sure e->next_offset covers remaining blob size Pablo Neira Ayuso
2016-03-28 17:57 ` [PATCH 6/9] netfilter: x_tables: fix unconditional helper Pablo Neira Ayuso
2016-03-28 17:58 ` [PATCH 7/9] netfilter: nfnetlink_queue: honor NFQA_CFG_F_FAIL_OPEN when netlink unicast fails Pablo Neira Ayuso
2016-03-28 17:58 ` [PATCH 8/9] netfilter: x_tables: enforce nul-terminated table name from getsockopt GET_ENTRIES Pablo Neira Ayuso
2016-03-28 17:58 ` [PATCH 9/9] netfilter: ipv4: fix NULL dereference Pablo Neira Ayuso
2016-03-28 19:43 ` [PATCH 0/9] Netfilter fixes for net David Miller

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