[PATCH 5.4 130/214] netfilter: avoid ipv6 -> nf_defrag_ipv6 module dependency

Greg Kroah-Hartman
2020-09-01T16:18:47Z

From: Florian Westphal <fw@strlen.de>

[ Upstream commit 2404b73c3f1a5f15726c6ecd226b56f6f992767f ]

nf_ct_frag6_gather is part of nf_defrag_ipv6.ko, not ipv6 core.

The current use of the netfilter ipv6 stub indirections causes a module
dependency between ipv6 and nf_defrag_ipv6.

This prevents nf_defrag_ipv6 module from being removed because ipv6 can't
be unloaded.

Remove the indirection and always use a direct call. This creates a
depency from nf_conntrack_bridge to nf_defrag_ipv6 instead:

modinfo nf_conntrack
depends: nf_conntrack,nf_defrag_ipv6,bridge

.. and nf_conntrack already depends on nf_defrag_ipv6 anyway.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/netfilter_ipv6.h | 18 ------------------
net/bridge/netfilter/nf_conntrack_bridge.c | 8 ++++++--
net/ipv6/netfilter.c | 3 ---
3 files changed, 6 insertions(+), 23 deletions(-)

diff --git a/include/linux/netfilter_ipv6.h b/include/linux/netfilter_ipv6.h
index aac42c28fe62d..9b67394471e1c 100644
--- a/include/linux/netfilter_ipv6.h
+++ b/include/linux/netfilter_ipv6.h
@@ -58,7 +58,6 @@ struct nf_ipv6_ops {
int (*output)(struct net *, struct sock *, struct sk_buff *));
int (*reroute)(struct sk_buff *skb, const struct nf_queue_entry *entry);
#if IS_MODULE(CONFIG_IPV6)
- int (*br_defrag)(struct net *net, struct sk_buff *skb, u32 user);
int (*br_fragment)(struct net *net, struct sock *sk,
struct sk_buff *skb,
struct nf_bridge_frag_data *data,
@@ -117,23 +116,6 @@ static inline int nf_ip6_route(struct net *net, struct dst_entry **dst,

#include <net/netfilter/ipv6/nf_defrag_ipv6.h>

-static inline int nf_ipv6_br_defrag(struct net *net, struct sk_buff *skb,
- u32 user)
-{
-#if IS_MODULE(CONFIG_IPV6)
- const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
-
- if (!v6_ops)
- return 1;
-
- return v6_ops->br_defrag(net, skb, user);
-#elif IS_BUILTIN(CONFIG_IPV6)
- return nf_ct_frag6_gather(net, skb, user);
-#else
- return 1;
-#endif
-}
-
int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
struct nf_bridge_frag_data *data,
int (*output)(struct net *, struct sock *sk,
diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c
index 8096732223828..8d033a75a766e 100644
--- a/net/bridge/netfilter/nf_conntrack_bridge.c
+++ b/net/bridge/netfilter/nf_conntrack_bridge.c
@@ -168,6 +168,7 @@ static unsigned int nf_ct_br_defrag4(struct sk_buff *skb,
static unsigned int nf_ct_br_defrag6(struct sk_buff *skb,
const struct nf_hook_state *state)
{
+#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
u16 zone_id = NF_CT_DEFAULT_ZONE_ID;
enum ip_conntrack_info ctinfo;
struct br_input_skb_cb cb;
@@ -180,14 +181,17 @@ static unsigned int nf_ct_br_defrag6(struct sk_buff *skb,

br_skb_cb_save(skb, &cb, sizeof(struct inet6_skb_parm));

- err = nf_ipv6_br_defrag(state->net, skb,
- IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id);
+ err = nf_ct_frag6_gather(state->net, skb,
+ IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id);
/* queued */
if (err == -EINPROGRESS)
return NF_STOLEN;

br_skb_cb_restore(skb, &cb, IP6CB(skb)->frag_max_size);
return err == 0 ? NF_ACCEPT : NF_DROP;
+#else
+ return NF_ACCEPT;
+#endif
}

static int nf_ct_br_ip_check(const struct sk_buff *skb)
diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c
index 409e79b84a830..6d0e942d082d4 100644
--- a/net/ipv6/netfilter.c
+++ b/net/ipv6/netfilter.c
@@ -245,9 +245,6 @@ static const struct nf_ipv6_ops ipv6ops = {
.route_input = ip6_route_input,
.fragment = ip6_fragment,
.reroute = nf_ip6_reroute,
-#if IS_MODULE(CONFIG_IPV6) && IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
- .br_defrag = nf_ct_frag6_gather,
-#endif
#if IS_MODULE(CONFIG_IPV6)
.br_fragment = br_ip6_fragment,
#endif
--
2.25.1