From: Florian Westphal <f...@strlen.de>
nf_defrag modules for ipv4 and ipv6 export an empty stub function.
Any module that needs the defragmentation hooks registered simply 'calls'
this empty function to create a phony module dependency -- modprobe will
then load the defrag module too.
This extends netfilter ipv4/ipv6 defragmentation modules to delay the hook
registration until the functionality is requested within a network namespace
instead of module load time for all namespaces.
Hooks are only un-registered on module unload or when a namespace that used
such defrag functionality exits.
We have to use struct net for this as the register hooks can be called
before netns initialization here from the ipv4/ipv6 conntrack module
init path.
There is no unregister functionality support, defrag will always be
active once it was requested inside a net namespace.
The reason is that defrag has impact on nft and iptables rulesets
(without defrag we might see framents).
Signed-off-by: Florian Westphal <f...@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
include/net/netfilter/ipv4/nf_defrag_ipv4.h | 3 +-
include/net/netfilter/ipv6/nf_defrag_ipv6.h | 3 +-
include/net/netns/netfilter.h | 6 ++++
net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c | 7 ++++-
net/ipv4/netfilter/nf_defrag_ipv4.c | 41 +++++++++++++++++++++++--
net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c | 7 ++++-
net/ipv6/netfilter/nf_defrag_ipv6_hooks.c | 42 +++++++++++++++++++++++---
net/netfilter/xt_TPROXY.c | 15 ++++++---
net/netfilter/xt_socket.c | 33 +++++++++++++++++---
9 files changed, 136 insertions(+), 21 deletions(-)
diff --git a/include/net/netfilter/ipv4/nf_defrag_ipv4.h
b/include/net/netfilter/ipv4/nf_defrag_ipv4.h
index f01ef208dff6..db405f70e538 100644
--- a/include/net/netfilter/ipv4/nf_defrag_ipv4.h
+++ b/include/net/netfilter/ipv4/nf_defrag_ipv4.h
@@ -1,6 +1,7 @@
#ifndef _NF_DEFRAG_IPV4_H
#define _NF_DEFRAG_IPV4_H
-void nf_defrag_ipv4_enable(void);
+struct net;
+int nf_defrag_ipv4_enable(struct net *);
#endif /* _NF_DEFRAG_IPV4_H */
diff --git a/include/net/netfilter/ipv6/nf_defrag_ipv6.h
b/include/net/netfilter/ipv6/nf_defrag_ipv6.h
index ddf162f7966f..7664efe37974 100644
--- a/include/net/netfilter/ipv6/nf_defrag_ipv6.h
+++ b/include/net/netfilter/ipv6/nf_defrag_ipv6.h
@@ -1,7 +1,8 @@
#ifndef _NF_DEFRAG_IPV6_H
#define _NF_DEFRAG_IPV6_H
-void nf_defrag_ipv6_enable(void);
+struct net;
+int nf_defrag_ipv6_enable(struct net *);
int nf_ct_frag6_init(void);
void nf_ct_frag6_cleanup(void);
diff --git a/include/net/netns/netfilter.h b/include/net/netns/netfilter.h
index 58487b1cc99a..cea396b53a60 100644
--- a/include/net/netns/netfilter.h
+++ b/include/net/netns/netfilter.h
@@ -17,5 +17,11 @@ struct netns_nf {
struct ctl_table_header *nf_log_dir_header;
#endif
struct nf_hook_entry __rcu *hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
+#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
+ bool defrag_ipv4;
+#endif
+#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
+ bool defrag_ipv6;
+#endif
};
#endif
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
index 6f375443a74b..fcfd071f4705 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
@@ -325,6 +325,12 @@ static int ipv4_hooks_register(struct net *net)
if (cnet->users > 1)
goto out_unlock;
+ err = nf_defrag_ipv4_enable(net);
+ if (err) {
+ cnet->users = 0;
+ goto out_unlock;
+ }
+
err = nf_register_net_hooks(net, ipv4_conntrack_ops,
ARRAY_SIZE(ipv4_conntrack_ops));
@@ -422,7 +428,6 @@ static int __init nf_conntrack_l3proto_ipv4_init(void)
int ret = 0;
need_conntrack();
- nf_defrag_ipv4_enable();
ret = nf_register_sockopt(&so_getorigdst);
if (ret < 0) {
diff --git a/net/ipv4/netfilter/nf_defrag_ipv4.c
b/net/ipv4/netfilter/nf_defrag_ipv4.c
index d88da36b383c..49bd6a54404f 100644
--- a/net/ipv4/netfilter/nf_defrag_ipv4.c
+++ b/net/ipv4/netfilter/nf_defrag_ipv4.c
@@ -11,6 +11,7 @@
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
+#include <net/netns/generic.h>
#include <net/route.h>
#include <net/ip.h>
@@ -22,6 +23,8 @@
#endif
#include <net/netfilter/nf_conntrack_zones.h>
+static DEFINE_MUTEX(defrag4_mutex);
+
static int nf_ct_ipv4_gather_frags(struct net *net, struct sk_buff *skb,
u_int32_t user)
{
@@ -102,18 +105,50 @@ static struct nf_hook_ops ipv4_defrag_ops[] = {
},
};
+static void __net_exit defrag4_net_exit(struct net *net)
+{
+ if (net->nf.defrag_ipv4) {
+ nf_unregister_net_hooks(net, ipv4_defrag_ops,
+ ARRAY_SIZE(ipv4_defrag_ops));
+ net->nf.defrag_ipv4 = false;
+ }
+}
+
+static struct pernet_operations defrag4_net_ops = {
+ .exit = defrag4_net_exit,
+};
+
static int __init nf_defrag_init(void)
{
- return nf_register_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
+ return register_pernet_subsys(&defrag4_net_ops);
}
static void __exit nf_defrag_fini(void)
{
- nf_unregister_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
+ unregister_pernet_subsys(&defrag4_net_ops);
}
-void nf_defrag_ipv4_enable(void)
+int nf_defrag_ipv4_enable(struct net *net)
{
+ int err = 0;
+
+ might_sleep();
+
+ if (net->nf.defrag_ipv4)
+ return 0;
+
+ mutex_lock(&defrag4_mutex);
+ if (net->nf.defrag_ipv4)
+ goto out_unlock;
+
+ err = nf_register_net_hooks(net, ipv4_defrag_ops,
+ ARRAY_SIZE(ipv4_defrag_ops));
+ if (err == 0)
+ net->nf.defrag_ipv4 = true;
+
+ out_unlock:
+ mutex_unlock(&defrag4_mutex);
+ return err;
}
EXPORT_SYMBOL_GPL(nf_defrag_ipv4_enable);
diff --git a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
index 72fe48075b7f..4e3402486833 100644
--- a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
+++ b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
@@ -325,6 +325,12 @@ static int ipv6_hooks_register(struct net *net)
if (cnet->users > 1)
goto out_unlock;
+ err = nf_defrag_ipv6_enable(net);
+ if (err < 0) {
+ cnet->users = 0;
+ goto out_unlock;
+ }
+
err = nf_register_net_hooks(net, ipv6_conntrack_ops,
ARRAY_SIZE(ipv6_conntrack_ops));
if (err)
@@ -427,7 +433,6 @@ static int __init nf_conntrack_l3proto_ipv6_init(void)
int ret = 0;
need_conntrack();
- nf_defrag_ipv6_enable();
ret = nf_register_sockopt(&so_getorigdst6);
if (ret < 0) {
diff --git a/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c
b/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c
index f06b0471f39f..8e0bdd058787 100644
--- a/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c
+++ b/net/ipv6/netfilter/nf_defrag_ipv6_hooks.c
@@ -30,6 +30,8 @@
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
+static DEFINE_MUTEX(defrag6_mutex);
+
static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum,
struct sk_buff *skb)
{
@@ -87,6 +89,19 @@ static struct nf_hook_ops ipv6_defrag_ops[] = {
},
};
+static void __net_exit defrag6_net_exit(struct net *net)
+{
+ if (net->nf.defrag_ipv6) {
+ nf_unregister_net_hooks(net, ipv6_defrag_ops,
+ ARRAY_SIZE(ipv6_defrag_ops));
+ net->nf.defrag_ipv6 = false;
+ }
+}
+
+static struct pernet_operations defrag6_net_ops = {
+ .exit = defrag6_net_exit,
+};
+
static int __init nf_defrag_init(void)
{
int ret = 0;
@@ -96,9 +111,9 @@ static int __init nf_defrag_init(void)
pr_err("nf_defrag_ipv6: can't initialize frag6.\n");
return ret;
}
- ret = nf_register_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
+ ret = register_pernet_subsys(&defrag6_net_ops);
if (ret < 0) {
- pr_err("nf_defrag_ipv6: can't register hooks\n");
+ pr_err("nf_defrag_ipv6: can't register pernet ops\n");
goto cleanup_frag6;
}
return ret;
@@ -111,12 +126,31 @@ static int __init nf_defrag_init(void)
static void __exit nf_defrag_fini(void)
{
- nf_unregister_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
+ unregister_pernet_subsys(&defrag6_net_ops);
nf_ct_frag6_cleanup();
}
-void nf_defrag_ipv6_enable(void)
+int nf_defrag_ipv6_enable(struct net *net)
{
+ int err = 0;
+
+ might_sleep();
+
+ if (net->nf.defrag_ipv6)
+ return 0;
+
+ mutex_lock(&defrag6_mutex);
+ if (net->nf.defrag_ipv6)
+ goto out_unlock;
+
+ err = nf_register_net_hooks(net, ipv6_defrag_ops,
+ ARRAY_SIZE(ipv6_defrag_ops));
+ if (err == 0)
+ net->nf.defrag_ipv6 = true;
+
+ out_unlock:
+ mutex_unlock(&defrag6_mutex);
+ return err;
}
EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);
diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c
index dbd72cc40e42..80cb7babeb64 100644
--- a/net/netfilter/xt_TPROXY.c
+++ b/net/netfilter/xt_TPROXY.c
@@ -531,6 +531,11 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct
xt_action_param *par)
static int tproxy_tg6_check(const struct xt_tgchk_param *par)
{
const struct ip6t_ip6 *i = par->entryinfo;
+ int err;
+
+ err = nf_defrag_ipv6_enable(par->net);
+ if (err)
+ return err;
if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP) &&
!(i->invflags & IP6T_INV_PROTO))
@@ -545,6 +550,11 @@ static int tproxy_tg6_check(const struct xt_tgchk_param
*par)
static int tproxy_tg4_check(const struct xt_tgchk_param *par)
{
const struct ipt_ip *i = par->entryinfo;
+ int err;
+
+ err = nf_defrag_ipv4_enable(par->net);
+ if (err)
+ return err;
if ((i->proto == IPPROTO_TCP || i->proto == IPPROTO_UDP)
&& !(i->invflags & IPT_INV_PROTO))
@@ -596,11 +606,6 @@ static struct xt_target tproxy_tg_reg[] __read_mostly = {
static int __init tproxy_tg_init(void)
{
- nf_defrag_ipv4_enable();
-#ifdef XT_TPROXY_HAVE_IPV6
- nf_defrag_ipv6_enable();
-#endif
-
return xt_register_targets(tproxy_tg_reg, ARRAY_SIZE(tproxy_tg_reg));
}
diff --git a/net/netfilter/xt_socket.c b/net/netfilter/xt_socket.c
index 2198914707f5..770bbec878f1 100644
--- a/net/netfilter/xt_socket.c
+++ b/net/netfilter/xt_socket.c
@@ -147,9 +147,28 @@ socket_mt6_v1_v2_v3(const struct sk_buff *skb, struct
xt_action_param *par)
}
#endif
+static int socket_mt_enable_defrag(struct net *net, int family)
+{
+ switch (family) {
+ case NFPROTO_IPV4:
+ return nf_defrag_ipv4_enable(net);
+#ifdef XT_SOCKET_HAVE_IPV6
+ case NFPROTO_IPV6:
+ return nf_defrag_ipv6_enable(net);
+#endif
+ }
+ WARN_ONCE(1, "Unknown family %d\n", family);
+ return 0;
+}
+
static int socket_mt_v1_check(const struct xt_mtchk_param *par)
{
const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *)
par->matchinfo;
+ int err;
+
+ err = socket_mt_enable_defrag(par->net, par->family);
+ if (err)
+ return err;
if (info->flags & ~XT_SOCKET_FLAGS_V1) {
pr_info("unknown flags 0x%x\n", info->flags &
~XT_SOCKET_FLAGS_V1);
@@ -161,6 +180,11 @@ static int socket_mt_v1_check(const struct xt_mtchk_param
*par)
static int socket_mt_v2_check(const struct xt_mtchk_param *par)
{
const struct xt_socket_mtinfo2 *info = (struct xt_socket_mtinfo2 *)
par->matchinfo;
+ int err;
+
+ err = socket_mt_enable_defrag(par->net, par->family);
+ if (err)
+ return err;
if (info->flags & ~XT_SOCKET_FLAGS_V2) {
pr_info("unknown flags 0x%x\n", info->flags &
~XT_SOCKET_FLAGS_V2);
@@ -173,7 +197,11 @@ static int socket_mt_v3_check(const struct xt_mtchk_param
*par)
{
const struct xt_socket_mtinfo3 *info =
(struct xt_socket_mtinfo3 *)par->matchinfo;
+ int err;
+ err = socket_mt_enable_defrag(par->net, par->family);
+ if (err)
+ return err;
if (info->flags & ~XT_SOCKET_FLAGS_V3) {
pr_info("unknown flags 0x%x\n",
info->flags & ~XT_SOCKET_FLAGS_V3);
@@ -268,11 +296,6 @@ static struct xt_match socket_mt_reg[] __read_mostly = {
static int __init socket_mt_init(void)
{
- nf_defrag_ipv4_enable();
-#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
- nf_defrag_ipv6_enable();
-#endif
-
return xt_register_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
}
--
2.1.4
--
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