1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * "TEE" target extension for Xtables
4 * Copyright © Sebastian Claßen, 2007
5 * Jan Engelhardt, 2007-2010
6 *
7 * based on ipt_ROUTE.c from Cédric de Launois
8 * <delaunois@info.ucl.be>
9 */
10 #include <linux/module.h>
11 #include <linux/skbuff.h>
12 #include <linux/route.h>
13 #include <linux/netfilter/x_tables.h>
14 #include <net/net_namespace.h>
15 #include <net/netns/generic.h>
16 #include <net/route.h>
17 #include <net/netfilter/ipv4/nf_dup_ipv4.h>
18 #include <net/netfilter/ipv6/nf_dup_ipv6.h>
19 #include <linux/netfilter/xt_TEE.h>
20
21 struct xt_tee_priv {
22 struct list_head list;
23 struct xt_tee_tginfo *tginfo;
24 int oif;
25 };
26
27 static unsigned int tee_net_id __read_mostly;
28 static const union nf_inet_addr tee_zero_address;
29
30 struct tee_net {
31 struct list_head priv_list;
32 /* lock protects the priv_list */
33 struct mutex lock;
34 };
35
36 static unsigned int
tee_tg4(struct sk_buff * skb,const struct xt_action_param * par)37 tee_tg4(struct sk_buff *skb, const struct xt_action_param *par)
38 {
39 const struct xt_tee_tginfo *info = par->targinfo;
40 int oif = info->priv ? info->priv->oif : 0;
41
42 nf_dup_ipv4(xt_net(par), skb, xt_hooknum(par), &info->gw.in, oif);
43
44 return XT_CONTINUE;
45 }
46
47 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
48 static unsigned int
tee_tg6(struct sk_buff * skb,const struct xt_action_param * par)49 tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
50 {
51 const struct xt_tee_tginfo *info = par->targinfo;
52 int oif = info->priv ? info->priv->oif : 0;
53
54 nf_dup_ipv6(xt_net(par), skb, xt_hooknum(par), &info->gw.in6, oif);
55
56 return XT_CONTINUE;
57 }
58 #endif
59
tee_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)60 static int tee_netdev_event(struct notifier_block *this, unsigned long event,
61 void *ptr)
62 {
63 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
64 struct net *net = dev_net(dev);
65 struct tee_net *tn = net_generic(net, tee_net_id);
66 struct xt_tee_priv *priv;
67
68 mutex_lock(&tn->lock);
69 list_for_each_entry(priv, &tn->priv_list, list) {
70 switch (event) {
71 case NETDEV_REGISTER:
72 if (!strcmp(dev->name, priv->tginfo->oif))
73 priv->oif = dev->ifindex;
74 break;
75 case NETDEV_UNREGISTER:
76 if (dev->ifindex == priv->oif)
77 priv->oif = -1;
78 break;
79 case NETDEV_CHANGENAME:
80 if (!strcmp(dev->name, priv->tginfo->oif))
81 priv->oif = dev->ifindex;
82 else if (dev->ifindex == priv->oif)
83 priv->oif = -1;
84 break;
85 }
86 }
87 mutex_unlock(&tn->lock);
88
89 return NOTIFY_DONE;
90 }
91
tee_tg_check(const struct xt_tgchk_param * par)92 static int tee_tg_check(const struct xt_tgchk_param *par)
93 {
94 struct tee_net *tn = net_generic(par->net, tee_net_id);
95 struct xt_tee_tginfo *info = par->targinfo;
96 struct xt_tee_priv *priv;
97
98 /* 0.0.0.0 and :: not allowed */
99 if (memcmp(&info->gw, &tee_zero_address,
100 sizeof(tee_zero_address)) == 0)
101 return -EINVAL;
102
103 if (info->oif[0]) {
104 struct net_device *dev;
105
106 if (info->oif[sizeof(info->oif)-1] != '\0')
107 return -EINVAL;
108
109 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
110 if (priv == NULL)
111 return -ENOMEM;
112
113 priv->tginfo = info;
114 priv->oif = -1;
115 info->priv = priv;
116
117 dev = dev_get_by_name(par->net, info->oif);
118 if (dev) {
119 priv->oif = dev->ifindex;
120 dev_put(dev);
121 }
122 mutex_lock(&tn->lock);
123 list_add(&priv->list, &tn->priv_list);
124 mutex_unlock(&tn->lock);
125 } else
126 info->priv = NULL;
127
128 static_key_slow_inc(&xt_tee_enabled);
129 return 0;
130 }
131
tee_tg_destroy(const struct xt_tgdtor_param * par)132 static void tee_tg_destroy(const struct xt_tgdtor_param *par)
133 {
134 struct tee_net *tn = net_generic(par->net, tee_net_id);
135 struct xt_tee_tginfo *info = par->targinfo;
136
137 if (info->priv) {
138 mutex_lock(&tn->lock);
139 list_del(&info->priv->list);
140 mutex_unlock(&tn->lock);
141 kfree(info->priv);
142 }
143 static_key_slow_dec(&xt_tee_enabled);
144 }
145
146 static struct xt_target tee_tg_reg[] __read_mostly = {
147 {
148 .name = "TEE",
149 .revision = 1,
150 .family = NFPROTO_IPV4,
151 .target = tee_tg4,
152 .targetsize = sizeof(struct xt_tee_tginfo),
153 .usersize = offsetof(struct xt_tee_tginfo, priv),
154 .checkentry = tee_tg_check,
155 .destroy = tee_tg_destroy,
156 .me = THIS_MODULE,
157 },
158 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
159 {
160 .name = "TEE",
161 .revision = 1,
162 .family = NFPROTO_IPV6,
163 .target = tee_tg6,
164 .targetsize = sizeof(struct xt_tee_tginfo),
165 .usersize = offsetof(struct xt_tee_tginfo, priv),
166 .checkentry = tee_tg_check,
167 .destroy = tee_tg_destroy,
168 .me = THIS_MODULE,
169 },
170 #endif
171 };
172
tee_net_init(struct net * net)173 static int __net_init tee_net_init(struct net *net)
174 {
175 struct tee_net *tn = net_generic(net, tee_net_id);
176
177 INIT_LIST_HEAD(&tn->priv_list);
178 mutex_init(&tn->lock);
179 return 0;
180 }
181
182 static struct pernet_operations tee_net_ops = {
183 .init = tee_net_init,
184 .id = &tee_net_id,
185 .size = sizeof(struct tee_net),
186 };
187
188 static struct notifier_block tee_netdev_notifier = {
189 .notifier_call = tee_netdev_event,
190 };
191
tee_tg_init(void)192 static int __init tee_tg_init(void)
193 {
194 int ret;
195
196 ret = register_pernet_subsys(&tee_net_ops);
197 if (ret < 0)
198 return ret;
199
200 ret = xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
201 if (ret < 0)
202 goto cleanup_subsys;
203
204 ret = register_netdevice_notifier(&tee_netdev_notifier);
205 if (ret < 0)
206 goto unregister_targets;
207
208 return 0;
209
210 unregister_targets:
211 xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
212 cleanup_subsys:
213 unregister_pernet_subsys(&tee_net_ops);
214 return ret;
215 }
216
tee_tg_exit(void)217 static void __exit tee_tg_exit(void)
218 {
219 unregister_netdevice_notifier(&tee_netdev_notifier);
220 xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
221 unregister_pernet_subsys(&tee_net_ops);
222 }
223
224 module_init(tee_tg_init);
225 module_exit(tee_tg_exit);
226 MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
227 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
228 MODULE_DESCRIPTION("Xtables: Reroute packet copy");
229 MODULE_LICENSE("GPL");
230 MODULE_ALIAS("ipt_TEE");
231 MODULE_ALIAS("ip6t_TEE");
232