1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Handle firewalling
4 * Linux ethernet bridge
5 *
6 * Authors:
7 * Lennert Buytenhek <buytenh@gnu.org>
8 * Bart De Schuymer <bdschuym@pandora.be>
9 *
10 * Lennert dedicates this file to Kerstin Wurdinger.
11 */
12
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/ip.h>
17 #include <linux/netdevice.h>
18 #include <linux/skbuff.h>
19 #include <linux/if_arp.h>
20 #include <linux/if_ether.h>
21 #include <linux/if_vlan.h>
22 #include <linux/if_pppox.h>
23 #include <linux/ppp_defs.h>
24 #include <linux/netfilter_bridge.h>
25 #include <uapi/linux/netfilter_bridge.h>
26 #include <linux/netfilter_ipv4.h>
27 #include <linux/netfilter_ipv6.h>
28 #include <linux/netfilter_arp.h>
29 #include <linux/in_route.h>
30 #include <linux/rculist.h>
31 #include <linux/inetdevice.h>
32
33 #include <net/ip.h>
34 #include <net/ipv6.h>
35 #include <net/addrconf.h>
36 #include <net/dst_metadata.h>
37 #include <net/route.h>
38 #include <net/netfilter/br_netfilter.h>
39 #include <net/netns/generic.h>
40 #include <net/inet_dscp.h>
41
42 #include <linux/uaccess.h>
43 #include "br_private.h"
44 #ifdef CONFIG_SYSCTL
45 #include <linux/sysctl.h>
46 #endif
47
48 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
49 #include <net/netfilter/nf_conntrack_core.h>
50 #endif
51
52 static unsigned int brnf_net_id __read_mostly;
53
54 struct brnf_net {
55 bool enabled;
56
57 #ifdef CONFIG_SYSCTL
58 struct ctl_table_header *ctl_hdr;
59 #endif
60
61 /* default value is 1 */
62 int call_iptables;
63 int call_ip6tables;
64 int call_arptables;
65
66 /* default value is 0 */
67 int filter_vlan_tagged;
68 int filter_pppoe_tagged;
69 int pass_vlan_indev;
70 };
71
72 #define IS_IP(skb) \
73 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IP))
74
75 #define IS_IPV6(skb) \
76 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_IPV6))
77
78 #define IS_ARP(skb) \
79 (!skb_vlan_tag_present(skb) && skb->protocol == htons(ETH_P_ARP))
80
vlan_proto(const struct sk_buff * skb)81 static inline __be16 vlan_proto(const struct sk_buff *skb)
82 {
83 if (skb_vlan_tag_present(skb))
84 return skb->protocol;
85 else if (skb->protocol == htons(ETH_P_8021Q))
86 return vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
87 else
88 return 0;
89 }
90
is_vlan_ip(const struct sk_buff * skb,const struct net * net)91 static inline bool is_vlan_ip(const struct sk_buff *skb, const struct net *net)
92 {
93 struct brnf_net *brnet = net_generic(net, brnf_net_id);
94
95 return vlan_proto(skb) == htons(ETH_P_IP) && brnet->filter_vlan_tagged;
96 }
97
is_vlan_ipv6(const struct sk_buff * skb,const struct net * net)98 static inline bool is_vlan_ipv6(const struct sk_buff *skb,
99 const struct net *net)
100 {
101 struct brnf_net *brnet = net_generic(net, brnf_net_id);
102
103 return vlan_proto(skb) == htons(ETH_P_IPV6) &&
104 brnet->filter_vlan_tagged;
105 }
106
is_vlan_arp(const struct sk_buff * skb,const struct net * net)107 static inline bool is_vlan_arp(const struct sk_buff *skb, const struct net *net)
108 {
109 struct brnf_net *brnet = net_generic(net, brnf_net_id);
110
111 return vlan_proto(skb) == htons(ETH_P_ARP) && brnet->filter_vlan_tagged;
112 }
113
pppoe_proto(const struct sk_buff * skb)114 static inline __be16 pppoe_proto(const struct sk_buff *skb)
115 {
116 return *((__be16 *)(skb_mac_header(skb) + ETH_HLEN +
117 sizeof(struct pppoe_hdr)));
118 }
119
is_pppoe_ip(const struct sk_buff * skb,const struct net * net)120 static inline bool is_pppoe_ip(const struct sk_buff *skb, const struct net *net)
121 {
122 struct brnf_net *brnet = net_generic(net, brnf_net_id);
123
124 return skb->protocol == htons(ETH_P_PPP_SES) &&
125 pppoe_proto(skb) == htons(PPP_IP) && brnet->filter_pppoe_tagged;
126 }
127
is_pppoe_ipv6(const struct sk_buff * skb,const struct net * net)128 static inline bool is_pppoe_ipv6(const struct sk_buff *skb,
129 const struct net *net)
130 {
131 struct brnf_net *brnet = net_generic(net, brnf_net_id);
132
133 return skb->protocol == htons(ETH_P_PPP_SES) &&
134 pppoe_proto(skb) == htons(PPP_IPV6) &&
135 brnet->filter_pppoe_tagged;
136 }
137
138 /* largest possible L2 header, see br_nf_dev_queue_xmit() */
139 #define NF_BRIDGE_MAX_MAC_HEADER_LENGTH (PPPOE_SES_HLEN + ETH_HLEN)
140
141 struct brnf_frag_data {
142 local_lock_t bh_lock;
143 char mac[NF_BRIDGE_MAX_MAC_HEADER_LENGTH];
144 u8 encap_size;
145 u8 size;
146 u16 vlan_tci;
147 __be16 vlan_proto;
148 };
149
150 static DEFINE_PER_CPU(struct brnf_frag_data, brnf_frag_data_storage) = {
151 .bh_lock = INIT_LOCAL_LOCK(bh_lock),
152 };
153
nf_bridge_info_free(struct sk_buff * skb)154 static void nf_bridge_info_free(struct sk_buff *skb)
155 {
156 skb_ext_del(skb, SKB_EXT_BRIDGE_NF);
157 }
158
bridge_parent(const struct net_device * dev)159 static inline struct net_device *bridge_parent(const struct net_device *dev)
160 {
161 struct net_bridge_port *port;
162
163 port = br_port_get_rcu(dev);
164 return port ? port->br->dev : NULL;
165 }
166
nf_bridge_unshare(struct sk_buff * skb)167 static inline struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb)
168 {
169 return skb_ext_add(skb, SKB_EXT_BRIDGE_NF);
170 }
171
nf_bridge_encap_header_len(const struct sk_buff * skb)172 unsigned int nf_bridge_encap_header_len(const struct sk_buff *skb)
173 {
174 switch (skb->protocol) {
175 case __cpu_to_be16(ETH_P_8021Q):
176 return VLAN_HLEN;
177 case __cpu_to_be16(ETH_P_PPP_SES):
178 return PPPOE_SES_HLEN;
179 default:
180 return 0;
181 }
182 }
183
nf_bridge_pull_encap_header(struct sk_buff * skb)184 static inline void nf_bridge_pull_encap_header(struct sk_buff *skb)
185 {
186 unsigned int len = nf_bridge_encap_header_len(skb);
187
188 skb_pull(skb, len);
189 skb->network_header += len;
190 }
191
nf_bridge_pull_encap_header_rcsum(struct sk_buff * skb)192 static inline void nf_bridge_pull_encap_header_rcsum(struct sk_buff *skb)
193 {
194 unsigned int len = nf_bridge_encap_header_len(skb);
195
196 skb_pull_rcsum(skb, len);
197 skb->network_header += len;
198 }
199
200 /* When handing a packet over to the IP layer
201 * check whether we have a skb that is in the
202 * expected format
203 */
204
br_validate_ipv4(struct net * net,struct sk_buff * skb)205 static int br_validate_ipv4(struct net *net, struct sk_buff *skb)
206 {
207 const struct iphdr *iph;
208 u32 len;
209
210 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
211 goto inhdr_error;
212
213 iph = ip_hdr(skb);
214
215 /* Basic sanity checks */
216 if (iph->ihl < 5 || iph->version != 4)
217 goto inhdr_error;
218
219 if (!pskb_may_pull(skb, iph->ihl*4))
220 goto inhdr_error;
221
222 iph = ip_hdr(skb);
223 if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
224 goto csum_error;
225
226 len = skb_ip_totlen(skb);
227 if (skb->len < len) {
228 __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS);
229 goto drop;
230 } else if (len < (iph->ihl*4))
231 goto inhdr_error;
232
233 if (pskb_trim_rcsum(skb, len)) {
234 __IP_INC_STATS(net, IPSTATS_MIB_INDISCARDS);
235 goto drop;
236 }
237
238 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
239 /* We should really parse IP options here but until
240 * somebody who actually uses IP options complains to
241 * us we'll just silently ignore the options because
242 * we're lazy!
243 */
244 return 0;
245
246 csum_error:
247 __IP_INC_STATS(net, IPSTATS_MIB_CSUMERRORS);
248 inhdr_error:
249 __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS);
250 drop:
251 return -1;
252 }
253
nf_bridge_update_protocol(struct sk_buff * skb)254 void nf_bridge_update_protocol(struct sk_buff *skb)
255 {
256 const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
257
258 switch (nf_bridge->orig_proto) {
259 case BRNF_PROTO_8021Q:
260 skb->protocol = htons(ETH_P_8021Q);
261 break;
262 case BRNF_PROTO_PPPOE:
263 skb->protocol = htons(ETH_P_PPP_SES);
264 break;
265 case BRNF_PROTO_UNCHANGED:
266 break;
267 }
268 }
269
270 /* Obtain the correct destination MAC address, while preserving the original
271 * source MAC address. If we already know this address, we just copy it. If we
272 * don't, we use the neighbour framework to find out. In both cases, we make
273 * sure that br_handle_frame_finish() is called afterwards.
274 */
br_nf_pre_routing_finish_bridge(struct net * net,struct sock * sk,struct sk_buff * skb)275 int br_nf_pre_routing_finish_bridge(struct net *net, struct sock *sk, struct sk_buff *skb)
276 {
277 struct neighbour *neigh;
278 struct dst_entry *dst;
279
280 skb->dev = bridge_parent(skb->dev);
281 if (!skb->dev)
282 goto free_skb;
283 dst = skb_dst(skb);
284 neigh = dst_neigh_lookup_skb(dst, skb);
285 if (neigh) {
286 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
287 int ret;
288
289 if ((READ_ONCE(neigh->nud_state) & NUD_CONNECTED) &&
290 READ_ONCE(neigh->hh.hh_len)) {
291 struct net_device *br_indev;
292
293 br_indev = nf_bridge_get_physindev(skb, net);
294 if (!br_indev) {
295 neigh_release(neigh);
296 goto free_skb;
297 }
298
299 neigh_hh_bridge(&neigh->hh, skb);
300 skb->dev = br_indev;
301
302 ret = br_handle_frame_finish(net, sk, skb);
303 } else {
304 /* the neighbour function below overwrites the complete
305 * MAC header, so we save the Ethernet source address and
306 * protocol number.
307 */
308 skb_copy_from_linear_data_offset(skb,
309 -(ETH_HLEN-ETH_ALEN),
310 nf_bridge->neigh_header,
311 ETH_HLEN-ETH_ALEN);
312 /* tell br_dev_xmit to continue with forwarding */
313 nf_bridge->bridged_dnat = 1;
314 /* FIXME Need to refragment */
315 ret = READ_ONCE(neigh->output)(neigh, skb);
316 }
317 neigh_release(neigh);
318 return ret;
319 }
320 free_skb:
321 kfree_skb(skb);
322 return 0;
323 }
324
325 static inline bool
br_nf_ipv4_daddr_was_changed(const struct sk_buff * skb,const struct nf_bridge_info * nf_bridge)326 br_nf_ipv4_daddr_was_changed(const struct sk_buff *skb,
327 const struct nf_bridge_info *nf_bridge)
328 {
329 return ip_hdr(skb)->daddr != nf_bridge->ipv4_daddr;
330 }
331
332 /* This requires some explaining. If DNAT has taken place,
333 * we will need to fix up the destination Ethernet address.
334 * This is also true when SNAT takes place (for the reply direction).
335 *
336 * There are two cases to consider:
337 * 1. The packet was DNAT'ed to a device in the same bridge
338 * port group as it was received on. We can still bridge
339 * the packet.
340 * 2. The packet was DNAT'ed to a different device, either
341 * a non-bridged device or another bridge port group.
342 * The packet will need to be routed.
343 *
344 * The correct way of distinguishing between these two cases is to
345 * call ip_route_input() and to look at skb->dst->dev, which is
346 * changed to the destination device if ip_route_input() succeeds.
347 *
348 * Let's first consider the case that ip_route_input() succeeds:
349 *
350 * If the output device equals the logical bridge device the packet
351 * came in on, we can consider this bridging. The corresponding MAC
352 * address will be obtained in br_nf_pre_routing_finish_bridge.
353 * Otherwise, the packet is considered to be routed and we just
354 * change the destination MAC address so that the packet will
355 * later be passed up to the IP stack to be routed. For a redirected
356 * packet, ip_route_input() will give back the localhost as output device,
357 * which differs from the bridge device.
358 *
359 * Let's now consider the case that ip_route_input() fails:
360 *
361 * This can be because the destination address is martian, in which case
362 * the packet will be dropped.
363 * If IP forwarding is disabled, ip_route_input() will fail, while
364 * ip_route_output_key() can return success. The source
365 * address for ip_route_output_key() is set to zero, so ip_route_output_key()
366 * thinks we're handling a locally generated packet and won't care
367 * if IP forwarding is enabled. If the output device equals the logical bridge
368 * device, we proceed as if ip_route_input() succeeded. If it differs from the
369 * logical bridge port or if ip_route_output_key() fails we drop the packet.
370 */
br_nf_pre_routing_finish(struct net * net,struct sock * sk,struct sk_buff * skb)371 static int br_nf_pre_routing_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
372 {
373 struct net_device *dev = skb->dev, *br_indev;
374 struct iphdr *iph = ip_hdr(skb);
375 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
376 struct rtable *rt;
377 int err;
378
379 br_indev = nf_bridge_get_physindev(skb, net);
380 if (!br_indev) {
381 kfree_skb(skb);
382 return 0;
383 }
384
385 nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
386
387 if (nf_bridge->pkt_otherhost) {
388 skb->pkt_type = PACKET_OTHERHOST;
389 nf_bridge->pkt_otherhost = false;
390 }
391 nf_bridge->in_prerouting = 0;
392 if (br_nf_ipv4_daddr_was_changed(skb, nf_bridge)) {
393 if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
394 struct in_device *in_dev = __in_dev_get_rcu(dev);
395
396 /* If err equals -EHOSTUNREACH the error is due to a
397 * martian destination or due to the fact that
398 * forwarding is disabled. For most martian packets,
399 * ip_route_output_key() will fail. It won't fail for 2 types of
400 * martian destinations: loopback destinations and destination
401 * 0.0.0.0. In both cases the packet will be dropped because the
402 * destination is the loopback device and not the bridge. */
403 if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev))
404 goto free_skb;
405
406 rt = ip_route_output(net, iph->daddr, 0,
407 iph->tos & INET_DSCP_MASK, 0,
408 RT_SCOPE_UNIVERSE);
409 if (!IS_ERR(rt)) {
410 /* - Bridged-and-DNAT'ed traffic doesn't
411 * require ip_forwarding. */
412 if (rt->dst.dev == dev) {
413 skb_dst_drop(skb);
414 skb_dst_set(skb, &rt->dst);
415 goto bridged_dnat;
416 }
417 ip_rt_put(rt);
418 }
419 free_skb:
420 kfree_skb(skb);
421 return 0;
422 } else {
423 if (skb_dst(skb)->dev == dev) {
424 bridged_dnat:
425 skb->dev = br_indev;
426 nf_bridge_update_protocol(skb);
427 nf_bridge_push_encap_header(skb);
428 br_nf_hook_thresh(NF_BR_PRE_ROUTING,
429 net, sk, skb, skb->dev,
430 NULL,
431 br_nf_pre_routing_finish_bridge);
432 return 0;
433 }
434 ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);
435 skb->pkt_type = PACKET_HOST;
436 }
437 } else {
438 rt = bridge_parent_rtable(br_indev);
439 if (!rt) {
440 kfree_skb(skb);
441 return 0;
442 }
443 skb_dst_drop(skb);
444 skb_dst_set_noref(skb, &rt->dst);
445 }
446
447 skb->dev = br_indev;
448 nf_bridge_update_protocol(skb);
449 nf_bridge_push_encap_header(skb);
450 br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb, skb->dev, NULL,
451 br_handle_frame_finish);
452 return 0;
453 }
454
brnf_get_logical_dev(struct sk_buff * skb,const struct net_device * dev,const struct net * net)455 static struct net_device *brnf_get_logical_dev(struct sk_buff *skb,
456 const struct net_device *dev,
457 const struct net *net)
458 {
459 struct net_device *vlan, *br;
460 struct brnf_net *brnet = net_generic(net, brnf_net_id);
461
462 br = bridge_parent(dev);
463
464 if (brnet->pass_vlan_indev == 0 || !skb_vlan_tag_present(skb))
465 return br;
466
467 vlan = __vlan_find_dev_deep_rcu(br, skb->vlan_proto,
468 skb_vlan_tag_get(skb) & VLAN_VID_MASK);
469
470 return vlan ? vlan : br;
471 }
472
473 /* Some common code for IPv4/IPv6 */
setup_pre_routing(struct sk_buff * skb,const struct net * net)474 struct net_device *setup_pre_routing(struct sk_buff *skb, const struct net *net)
475 {
476 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
477
478 if (skb->pkt_type == PACKET_OTHERHOST) {
479 skb->pkt_type = PACKET_HOST;
480 nf_bridge->pkt_otherhost = true;
481 }
482
483 nf_bridge->in_prerouting = 1;
484 nf_bridge->physinif = skb->dev->ifindex;
485 skb->dev = brnf_get_logical_dev(skb, skb->dev, net);
486
487 if (skb->protocol == htons(ETH_P_8021Q))
488 nf_bridge->orig_proto = BRNF_PROTO_8021Q;
489 else if (skb->protocol == htons(ETH_P_PPP_SES))
490 nf_bridge->orig_proto = BRNF_PROTO_PPPOE;
491
492 /* Must drop socket now because of tproxy. */
493 skb_orphan(skb);
494 return skb->dev;
495 }
496
497 /* Direct IPv6 traffic to br_nf_pre_routing_ipv6.
498 * Replicate the checks that IPv4 does on packet reception.
499 * Set skb->dev to the bridge device (i.e. parent of the
500 * receiving device) to make netfilter happy, the REDIRECT
501 * target in particular. Save the original destination IP
502 * address to be able to detect DNAT afterwards. */
br_nf_pre_routing(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)503 static unsigned int br_nf_pre_routing(void *priv,
504 struct sk_buff *skb,
505 const struct nf_hook_state *state)
506 {
507 struct nf_bridge_info *nf_bridge;
508 struct net_bridge_port *p;
509 struct net_bridge *br;
510 __u32 len = nf_bridge_encap_header_len(skb);
511 struct brnf_net *brnet;
512
513 if (unlikely(!pskb_may_pull(skb, len)))
514 return NF_DROP_REASON(skb, SKB_DROP_REASON_PKT_TOO_SMALL, 0);
515
516 p = br_port_get_rcu(state->in);
517 if (p == NULL)
518 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
519 br = p->br;
520
521 brnet = net_generic(state->net, brnf_net_id);
522 if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
523 is_pppoe_ipv6(skb, state->net)) {
524 if (!brnet->call_ip6tables &&
525 !br_opt_get(br, BROPT_NF_CALL_IP6TABLES))
526 return NF_ACCEPT;
527 if (!ipv6_mod_enabled()) {
528 pr_warn_once("Module ipv6 is disabled, so call_ip6tables is not supported.");
529 return NF_DROP_REASON(skb, SKB_DROP_REASON_IPV6DISABLED, 0);
530 }
531
532 nf_bridge_pull_encap_header_rcsum(skb);
533 return br_nf_pre_routing_ipv6(priv, skb, state);
534 }
535
536 if (!brnet->call_iptables && !br_opt_get(br, BROPT_NF_CALL_IPTABLES))
537 return NF_ACCEPT;
538
539 if (!IS_IP(skb) && !is_vlan_ip(skb, state->net) &&
540 !is_pppoe_ip(skb, state->net))
541 return NF_ACCEPT;
542
543 nf_bridge_pull_encap_header_rcsum(skb);
544
545 if (br_validate_ipv4(state->net, skb))
546 return NF_DROP_REASON(skb, SKB_DROP_REASON_IP_INHDR, 0);
547
548 if (!nf_bridge_alloc(skb))
549 return NF_DROP_REASON(skb, SKB_DROP_REASON_NOMEM, 0);
550 if (!setup_pre_routing(skb, state->net))
551 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
552
553 nf_bridge = nf_bridge_info_get(skb);
554 nf_bridge->ipv4_daddr = ip_hdr(skb)->daddr;
555
556 skb->protocol = htons(ETH_P_IP);
557 skb->transport_header = skb->network_header + ip_hdr(skb)->ihl * 4;
558
559 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, state->net, state->sk, skb,
560 skb->dev, NULL,
561 br_nf_pre_routing_finish);
562
563 return NF_STOLEN;
564 }
565
566 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
567 /* conntracks' nf_confirm logic cannot handle cloned skbs referencing
568 * the same nf_conn entry, which will happen for multicast (broadcast)
569 * Frames on bridges.
570 *
571 * Example:
572 * macvlan0
573 * br0
574 * ethX ethY
575 *
576 * ethX (or Y) receives multicast or broadcast packet containing
577 * an IP packet, not yet in conntrack table.
578 *
579 * 1. skb passes through bridge and fake-ip (br_netfilter)Prerouting.
580 * -> skb->_nfct now references a unconfirmed entry
581 * 2. skb is broad/mcast packet. bridge now passes clones out on each bridge
582 * interface.
583 * 3. skb gets passed up the stack.
584 * 4. In macvlan case, macvlan driver retains clone(s) of the mcast skb
585 * and schedules a work queue to send them out on the lower devices.
586 *
587 * The clone skb->_nfct is not a copy, it is the same entry as the
588 * original skb. The macvlan rx handler then returns RX_HANDLER_PASS.
589 * 5. Normal conntrack hooks (in NF_INET_LOCAL_IN) confirm the orig skb.
590 *
591 * The Macvlan broadcast worker and normal confirm path will race.
592 *
593 * This race will not happen if step 2 already confirmed a clone. In that
594 * case later steps perform skb_clone() with skb->_nfct already confirmed (in
595 * hash table). This works fine.
596 *
597 * But such confirmation won't happen when eb/ip/nftables rules dropped the
598 * packets before they reached the nf_confirm step in postrouting.
599 *
600 * Work around this problem by explicit confirmation of the entry at
601 * LOCAL_IN time, before upper layer has a chance to clone the unconfirmed
602 * entry.
603 *
604 */
br_nf_local_in(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)605 static unsigned int br_nf_local_in(void *priv,
606 struct sk_buff *skb,
607 const struct nf_hook_state *state)
608 {
609 bool promisc = BR_INPUT_SKB_CB(skb)->promisc;
610 struct nf_conntrack *nfct = skb_nfct(skb);
611 const struct nf_ct_hook *ct_hook;
612 struct nf_conn *ct;
613 int ret;
614
615 if (promisc) {
616 nf_reset_ct(skb);
617 return NF_ACCEPT;
618 }
619
620 if (!nfct || skb->pkt_type == PACKET_HOST)
621 return NF_ACCEPT;
622
623 ct = container_of(nfct, struct nf_conn, ct_general);
624 if (likely(nf_ct_is_confirmed(ct)))
625 return NF_ACCEPT;
626
627 if (WARN_ON_ONCE(refcount_read(&nfct->use) != 1)) {
628 nf_reset_ct(skb);
629 return NF_ACCEPT;
630 }
631
632 WARN_ON_ONCE(skb_shared(skb));
633
634 /* We can't call nf_confirm here, it would create a dependency
635 * on nf_conntrack module.
636 */
637 ct_hook = rcu_dereference(nf_ct_hook);
638 if (!ct_hook) {
639 skb->_nfct = 0ul;
640 nf_conntrack_put(nfct);
641 return NF_ACCEPT;
642 }
643
644 nf_bridge_pull_encap_header(skb);
645 ret = ct_hook->confirm(skb);
646 switch (ret & NF_VERDICT_MASK) {
647 case NF_STOLEN:
648 return NF_STOLEN;
649 default:
650 nf_bridge_push_encap_header(skb);
651 break;
652 }
653
654 ct = container_of(nfct, struct nf_conn, ct_general);
655 WARN_ON_ONCE(!nf_ct_is_confirmed(ct));
656
657 return ret;
658 }
659 #endif
660
661 /* PF_BRIDGE/FORWARD *************************************************/
br_nf_forward_finish(struct net * net,struct sock * sk,struct sk_buff * skb)662 static int br_nf_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
663 {
664 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
665 struct net_device *in;
666
667 if (!IS_ARP(skb) && !is_vlan_arp(skb, net)) {
668
669 if (skb->protocol == htons(ETH_P_IP))
670 nf_bridge->frag_max_size = IPCB(skb)->frag_max_size;
671
672 if (skb->protocol == htons(ETH_P_IPV6))
673 nf_bridge->frag_max_size = IP6CB(skb)->frag_max_size;
674
675 in = nf_bridge_get_physindev(skb, net);
676 if (!in) {
677 kfree_skb(skb);
678 return 0;
679 }
680 if (nf_bridge->pkt_otherhost) {
681 skb->pkt_type = PACKET_OTHERHOST;
682 nf_bridge->pkt_otherhost = false;
683 }
684 nf_bridge_update_protocol(skb);
685 } else {
686 in = *((struct net_device **)(skb->cb));
687 }
688 nf_bridge_push_encap_header(skb);
689
690 br_nf_hook_thresh(NF_BR_FORWARD, net, sk, skb, in, skb->dev,
691 br_forward_finish);
692 return 0;
693 }
694
695
br_nf_forward_ip(struct sk_buff * skb,const struct nf_hook_state * state,u8 pf)696 static unsigned int br_nf_forward_ip(struct sk_buff *skb,
697 const struct nf_hook_state *state,
698 u8 pf)
699 {
700 struct nf_bridge_info *nf_bridge;
701 struct net_device *parent;
702
703 nf_bridge = nf_bridge_info_get(skb);
704 if (!nf_bridge)
705 return NF_ACCEPT;
706
707 /* Need exclusive nf_bridge_info since we might have multiple
708 * different physoutdevs. */
709 if (!nf_bridge_unshare(skb))
710 return NF_DROP_REASON(skb, SKB_DROP_REASON_NOMEM, 0);
711
712 nf_bridge = nf_bridge_info_get(skb);
713 if (!nf_bridge)
714 return NF_DROP_REASON(skb, SKB_DROP_REASON_NOMEM, 0);
715
716 parent = bridge_parent(state->out);
717 if (!parent)
718 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
719
720 nf_bridge_pull_encap_header(skb);
721
722 if (skb->pkt_type == PACKET_OTHERHOST) {
723 skb->pkt_type = PACKET_HOST;
724 nf_bridge->pkt_otherhost = true;
725 }
726
727 if (pf == NFPROTO_IPV4) {
728 if (br_validate_ipv4(state->net, skb))
729 return NF_DROP_REASON(skb, SKB_DROP_REASON_IP_INHDR, 0);
730 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
731 skb->protocol = htons(ETH_P_IP);
732 } else if (pf == NFPROTO_IPV6) {
733 if (br_validate_ipv6(state->net, skb))
734 return NF_DROP_REASON(skb, SKB_DROP_REASON_IP_INHDR, 0);
735 IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
736 skb->protocol = htons(ETH_P_IPV6);
737 } else {
738 WARN_ON_ONCE(1);
739 return NF_DROP;
740 }
741
742 nf_bridge->physoutdev = skb->dev;
743
744 NF_HOOK(pf, NF_INET_FORWARD, state->net, NULL, skb,
745 brnf_get_logical_dev(skb, state->in, state->net),
746 parent, br_nf_forward_finish);
747
748 return NF_STOLEN;
749 }
750
br_nf_forward_arp(struct sk_buff * skb,const struct nf_hook_state * state)751 static unsigned int br_nf_forward_arp(struct sk_buff *skb,
752 const struct nf_hook_state *state)
753 {
754 struct net_bridge_port *p;
755 struct net_bridge *br;
756 struct net_device **d = (struct net_device **)(skb->cb);
757 struct brnf_net *brnet;
758
759 p = br_port_get_rcu(state->out);
760 if (p == NULL)
761 return NF_ACCEPT;
762 br = p->br;
763
764 brnet = net_generic(state->net, brnf_net_id);
765 if (!brnet->call_arptables && !br_opt_get(br, BROPT_NF_CALL_ARPTABLES))
766 return NF_ACCEPT;
767
768 if (is_vlan_arp(skb, state->net))
769 nf_bridge_pull_encap_header(skb);
770
771 if (unlikely(!pskb_may_pull(skb, sizeof(struct arphdr))))
772 return NF_DROP_REASON(skb, SKB_DROP_REASON_PKT_TOO_SMALL, 0);
773
774 if (arp_hdr(skb)->ar_pln != 4) {
775 if (is_vlan_arp(skb, state->net))
776 nf_bridge_push_encap_header(skb);
777 return NF_ACCEPT;
778 }
779 *d = state->in;
780 NF_HOOK(NFPROTO_ARP, NF_ARP_FORWARD, state->net, state->sk, skb,
781 state->in, state->out, br_nf_forward_finish);
782
783 return NF_STOLEN;
784 }
785
786 /* This is the 'purely bridged' case. For IP, we pass the packet to
787 * netfilter with indev and outdev set to the bridge device,
788 * but we are still able to filter on the 'real' indev/outdev
789 * because of the physdev module. For ARP, indev and outdev are the
790 * bridge ports.
791 */
br_nf_forward(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)792 static unsigned int br_nf_forward(void *priv,
793 struct sk_buff *skb,
794 const struct nf_hook_state *state)
795 {
796 if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
797 is_pppoe_ip(skb, state->net))
798 return br_nf_forward_ip(skb, state, NFPROTO_IPV4);
799 if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
800 is_pppoe_ipv6(skb, state->net))
801 return br_nf_forward_ip(skb, state, NFPROTO_IPV6);
802 if (IS_ARP(skb) || is_vlan_arp(skb, state->net))
803 return br_nf_forward_arp(skb, state);
804
805 return NF_ACCEPT;
806 }
807
br_nf_push_frag_xmit(struct net * net,struct sock * sk,struct sk_buff * skb)808 static int br_nf_push_frag_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
809 {
810 struct brnf_frag_data *data;
811 int err;
812
813 data = this_cpu_ptr(&brnf_frag_data_storage);
814 err = skb_cow_head(skb, data->size);
815
816 if (err) {
817 kfree_skb(skb);
818 return 0;
819 }
820
821 if (data->vlan_proto)
822 __vlan_hwaccel_put_tag(skb, data->vlan_proto, data->vlan_tci);
823
824 skb_copy_to_linear_data_offset(skb, -data->size, data->mac, data->size);
825 __skb_push(skb, data->encap_size);
826
827 nf_bridge_info_free(skb);
828 return br_dev_queue_push_xmit(net, sk, skb);
829 }
830
831 static int
br_nf_ip_fragment(struct net * net,struct sock * sk,struct sk_buff * skb,int (* output)(struct net *,struct sock *,struct sk_buff *))832 br_nf_ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
833 int (*output)(struct net *, struct sock *, struct sk_buff *))
834 {
835 unsigned int mtu = ip_skb_dst_mtu(sk, skb);
836 struct iphdr *iph = ip_hdr(skb);
837
838 if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
839 (IPCB(skb)->frag_max_size &&
840 IPCB(skb)->frag_max_size > mtu))) {
841 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
842 kfree_skb(skb);
843 return -EMSGSIZE;
844 }
845
846 return ip_do_fragment(net, sk, skb, output);
847 }
848
nf_bridge_mtu_reduction(const struct sk_buff * skb)849 static unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
850 {
851 const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
852
853 if (nf_bridge->orig_proto == BRNF_PROTO_PPPOE)
854 return PPPOE_SES_HLEN;
855 return 0;
856 }
857
br_nf_dev_queue_xmit(struct net * net,struct sock * sk,struct sk_buff * skb)858 static int br_nf_dev_queue_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
859 {
860 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
861 unsigned int mtu, mtu_reserved;
862 int ret;
863
864 mtu_reserved = nf_bridge_mtu_reduction(skb);
865 mtu = skb->dev->mtu;
866
867 if (nf_bridge->pkt_otherhost) {
868 skb->pkt_type = PACKET_OTHERHOST;
869 nf_bridge->pkt_otherhost = false;
870 }
871
872 if (nf_bridge->frag_max_size && nf_bridge->frag_max_size < mtu)
873 mtu = nf_bridge->frag_max_size;
874
875 nf_bridge_update_protocol(skb);
876 nf_bridge_push_encap_header(skb);
877
878 if (skb_is_gso(skb) || skb->len + mtu_reserved <= mtu) {
879 nf_bridge_info_free(skb);
880 return br_dev_queue_push_xmit(net, sk, skb);
881 }
882
883 /* Fragmentation on metadata/template dst is not supported */
884 if (unlikely(!skb_valid_dst(skb)))
885 goto drop;
886
887 /* This is wrong! We should preserve the original fragment
888 * boundaries by preserving frag_list rather than refragmenting.
889 */
890 if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV4) &&
891 skb->protocol == htons(ETH_P_IP)) {
892 struct brnf_frag_data *data;
893
894 if (br_validate_ipv4(net, skb))
895 goto drop;
896
897 IPCB(skb)->frag_max_size = nf_bridge->frag_max_size;
898
899 local_lock_nested_bh(&brnf_frag_data_storage.bh_lock);
900 data = this_cpu_ptr(&brnf_frag_data_storage);
901
902 if (skb_vlan_tag_present(skb)) {
903 data->vlan_tci = skb->vlan_tci;
904 data->vlan_proto = skb->vlan_proto;
905 } else {
906 data->vlan_proto = 0;
907 }
908
909 data->encap_size = nf_bridge_encap_header_len(skb);
910 data->size = ETH_HLEN + data->encap_size;
911
912 skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
913 data->size);
914
915 ret = br_nf_ip_fragment(net, sk, skb, br_nf_push_frag_xmit);
916 local_unlock_nested_bh(&brnf_frag_data_storage.bh_lock);
917 return ret;
918 }
919 if (IS_ENABLED(CONFIG_NF_DEFRAG_IPV6) &&
920 skb->protocol == htons(ETH_P_IPV6)) {
921 const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
922 struct brnf_frag_data *data;
923
924 if (br_validate_ipv6(net, skb))
925 goto drop;
926
927 IP6CB(skb)->frag_max_size = nf_bridge->frag_max_size;
928
929 local_lock_nested_bh(&brnf_frag_data_storage.bh_lock);
930 data = this_cpu_ptr(&brnf_frag_data_storage);
931 data->encap_size = nf_bridge_encap_header_len(skb);
932 data->size = ETH_HLEN + data->encap_size;
933
934 skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
935 data->size);
936
937 if (v6ops) {
938 ret = v6ops->fragment(net, sk, skb, br_nf_push_frag_xmit);
939 local_unlock_nested_bh(&brnf_frag_data_storage.bh_lock);
940 return ret;
941 }
942 local_unlock_nested_bh(&brnf_frag_data_storage.bh_lock);
943
944 kfree_skb(skb);
945 return -EMSGSIZE;
946 }
947 nf_bridge_info_free(skb);
948 return br_dev_queue_push_xmit(net, sk, skb);
949 drop:
950 kfree_skb(skb);
951 return 0;
952 }
953
954 /* PF_BRIDGE/POST_ROUTING ********************************************/
br_nf_post_routing(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)955 static unsigned int br_nf_post_routing(void *priv,
956 struct sk_buff *skb,
957 const struct nf_hook_state *state)
958 {
959 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
960 struct net_device *realoutdev = bridge_parent(skb->dev);
961 u_int8_t pf;
962
963 /* if nf_bridge is set, but ->physoutdev is NULL, this packet came in
964 * on a bridge, but was delivered locally and is now being routed:
965 *
966 * POST_ROUTING was already invoked from the ip stack.
967 */
968 if (!nf_bridge || !nf_bridge->physoutdev)
969 return NF_ACCEPT;
970
971 if (!realoutdev)
972 return NF_DROP_REASON(skb, SKB_DROP_REASON_DEV_READY, 0);
973
974 if (IS_IP(skb) || is_vlan_ip(skb, state->net) ||
975 is_pppoe_ip(skb, state->net))
976 pf = NFPROTO_IPV4;
977 else if (IS_IPV6(skb) || is_vlan_ipv6(skb, state->net) ||
978 is_pppoe_ipv6(skb, state->net))
979 pf = NFPROTO_IPV6;
980 else
981 return NF_ACCEPT;
982
983 if (skb->pkt_type == PACKET_OTHERHOST) {
984 skb->pkt_type = PACKET_HOST;
985 nf_bridge->pkt_otherhost = true;
986 }
987
988 nf_bridge_pull_encap_header(skb);
989 if (pf == NFPROTO_IPV4)
990 skb->protocol = htons(ETH_P_IP);
991 else
992 skb->protocol = htons(ETH_P_IPV6);
993
994 NF_HOOK(pf, NF_INET_POST_ROUTING, state->net, state->sk, skb,
995 NULL, realoutdev,
996 br_nf_dev_queue_xmit);
997
998 return NF_STOLEN;
999 }
1000
1001 /* IP/SABOTAGE *****************************************************/
1002 /* Don't hand locally destined packets to PF_INET(6)/PRE_ROUTING
1003 * for the second time. */
ip_sabotage_in(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)1004 static unsigned int ip_sabotage_in(void *priv,
1005 struct sk_buff *skb,
1006 const struct nf_hook_state *state)
1007 {
1008 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
1009
1010 if (nf_bridge) {
1011 if (nf_bridge->sabotage_in_done)
1012 return NF_ACCEPT;
1013
1014 if (!nf_bridge->in_prerouting &&
1015 !netif_is_l3_master(skb->dev) &&
1016 !netif_is_l3_slave(skb->dev)) {
1017 nf_bridge->sabotage_in_done = 1;
1018 state->okfn(state->net, state->sk, skb);
1019 return NF_STOLEN;
1020 }
1021 }
1022
1023 return NF_ACCEPT;
1024 }
1025
1026 /* This is called when br_netfilter has called into iptables/netfilter,
1027 * and DNAT has taken place on a bridge-forwarded packet.
1028 *
1029 * neigh->output has created a new MAC header, with local br0 MAC
1030 * as saddr.
1031 *
1032 * This restores the original MAC saddr of the bridged packet
1033 * before invoking bridge forward logic to transmit the packet.
1034 */
br_nf_pre_routing_finish_bridge_slow(struct sk_buff * skb)1035 static void br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
1036 {
1037 struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
1038 struct net_device *br_indev;
1039
1040 br_indev = nf_bridge_get_physindev(skb, dev_net(skb->dev));
1041 if (!br_indev) {
1042 kfree_skb(skb);
1043 return;
1044 }
1045
1046 skb_pull(skb, ETH_HLEN);
1047 nf_bridge->bridged_dnat = 0;
1048
1049 BUILD_BUG_ON(sizeof(nf_bridge->neigh_header) != (ETH_HLEN - ETH_ALEN));
1050
1051 skb_copy_to_linear_data_offset(skb, -(ETH_HLEN - ETH_ALEN),
1052 nf_bridge->neigh_header,
1053 ETH_HLEN - ETH_ALEN);
1054 skb->dev = br_indev;
1055
1056 nf_bridge->physoutdev = NULL;
1057 br_handle_frame_finish(dev_net(skb->dev), NULL, skb);
1058 }
1059
br_nf_dev_xmit(struct sk_buff * skb)1060 static int br_nf_dev_xmit(struct sk_buff *skb)
1061 {
1062 const struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
1063
1064 if (nf_bridge && nf_bridge->bridged_dnat) {
1065 br_nf_pre_routing_finish_bridge_slow(skb);
1066 return 1;
1067 }
1068 return 0;
1069 }
1070
1071 static const struct nf_br_ops br_ops = {
1072 .br_dev_xmit_hook = br_nf_dev_xmit,
1073 };
1074
1075 /* For br_nf_post_routing, we need (prio = NF_BR_PRI_LAST), because
1076 * br_dev_queue_push_xmit is called afterwards */
1077 static const struct nf_hook_ops br_nf_ops[] = {
1078 {
1079 .hook = br_nf_pre_routing,
1080 .pf = NFPROTO_BRIDGE,
1081 .hooknum = NF_BR_PRE_ROUTING,
1082 .priority = NF_BR_PRI_BRNF,
1083 },
1084 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
1085 {
1086 .hook = br_nf_local_in,
1087 .pf = NFPROTO_BRIDGE,
1088 .hooknum = NF_BR_LOCAL_IN,
1089 .priority = NF_BR_PRI_LAST,
1090 },
1091 #endif
1092 {
1093 .hook = br_nf_forward,
1094 .pf = NFPROTO_BRIDGE,
1095 .hooknum = NF_BR_FORWARD,
1096 .priority = NF_BR_PRI_BRNF,
1097 },
1098 {
1099 .hook = br_nf_post_routing,
1100 .pf = NFPROTO_BRIDGE,
1101 .hooknum = NF_BR_POST_ROUTING,
1102 .priority = NF_BR_PRI_LAST,
1103 },
1104 {
1105 .hook = ip_sabotage_in,
1106 .pf = NFPROTO_IPV4,
1107 .hooknum = NF_INET_PRE_ROUTING,
1108 .priority = NF_IP_PRI_FIRST,
1109 },
1110 {
1111 .hook = ip_sabotage_in,
1112 .pf = NFPROTO_IPV6,
1113 .hooknum = NF_INET_PRE_ROUTING,
1114 .priority = NF_IP6_PRI_FIRST,
1115 },
1116 };
1117
brnf_device_event(struct notifier_block * unused,unsigned long event,void * ptr)1118 static int brnf_device_event(struct notifier_block *unused, unsigned long event,
1119 void *ptr)
1120 {
1121 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1122 struct brnf_net *brnet;
1123 struct net *net;
1124 int ret;
1125
1126 if (event != NETDEV_REGISTER || !netif_is_bridge_master(dev))
1127 return NOTIFY_DONE;
1128
1129 ASSERT_RTNL();
1130
1131 net = dev_net(dev);
1132 brnet = net_generic(net, brnf_net_id);
1133 if (brnet->enabled)
1134 return NOTIFY_OK;
1135
1136 ret = nf_register_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
1137 if (ret)
1138 return NOTIFY_BAD;
1139
1140 brnet->enabled = true;
1141 return NOTIFY_OK;
1142 }
1143
1144 static struct notifier_block brnf_notifier __read_mostly = {
1145 .notifier_call = brnf_device_event,
1146 };
1147
1148 /* recursively invokes nf_hook_slow (again), skipping already-called
1149 * hooks (< NF_BR_PRI_BRNF).
1150 *
1151 * Called with rcu read lock held.
1152 */
br_nf_hook_thresh(unsigned int hook,struct net * net,struct sock * sk,struct sk_buff * skb,struct net_device * indev,struct net_device * outdev,int (* okfn)(struct net *,struct sock *,struct sk_buff *))1153 int br_nf_hook_thresh(unsigned int hook, struct net *net,
1154 struct sock *sk, struct sk_buff *skb,
1155 struct net_device *indev,
1156 struct net_device *outdev,
1157 int (*okfn)(struct net *, struct sock *,
1158 struct sk_buff *))
1159 {
1160 const struct nf_hook_entries *e;
1161 struct nf_hook_state state;
1162 struct nf_hook_ops **ops;
1163 unsigned int i;
1164 int ret;
1165
1166 e = rcu_dereference(net->nf.hooks_bridge[hook]);
1167 if (!e)
1168 return okfn(net, sk, skb);
1169
1170 ops = nf_hook_entries_get_hook_ops(e);
1171 for (i = 0; i < e->num_hook_entries; i++) {
1172 /* These hooks have already been called */
1173 if (ops[i]->priority < NF_BR_PRI_BRNF)
1174 continue;
1175
1176 /* These hooks have not been called yet, run them. */
1177 if (ops[i]->priority > NF_BR_PRI_BRNF)
1178 break;
1179
1180 /* take a closer look at NF_BR_PRI_BRNF. */
1181 if (ops[i]->hook == br_nf_pre_routing) {
1182 /* This hook diverted the skb to this function,
1183 * hooks after this have not been run yet.
1184 */
1185 i++;
1186 break;
1187 }
1188 }
1189
1190 nf_hook_state_init(&state, hook, NFPROTO_BRIDGE, indev, outdev,
1191 sk, net, okfn);
1192
1193 ret = nf_hook_slow(skb, &state, e, i);
1194 if (ret == 1)
1195 ret = okfn(net, sk, skb);
1196
1197 return ret;
1198 }
1199
1200 #ifdef CONFIG_SYSCTL
1201 static
brnf_sysctl_call_tables(const struct ctl_table * ctl,int write,void * buffer,size_t * lenp,loff_t * ppos)1202 int brnf_sysctl_call_tables(const struct ctl_table *ctl, int write,
1203 void *buffer, size_t *lenp, loff_t *ppos)
1204 {
1205 int ret;
1206
1207 ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
1208
1209 if (write && *(int *)(ctl->data))
1210 *(int *)(ctl->data) = 1;
1211 return ret;
1212 }
1213
1214 static struct ctl_table brnf_table[] = {
1215 {
1216 .procname = "bridge-nf-call-arptables",
1217 .maxlen = sizeof(int),
1218 .mode = 0644,
1219 .proc_handler = brnf_sysctl_call_tables,
1220 },
1221 {
1222 .procname = "bridge-nf-call-iptables",
1223 .maxlen = sizeof(int),
1224 .mode = 0644,
1225 .proc_handler = brnf_sysctl_call_tables,
1226 },
1227 {
1228 .procname = "bridge-nf-call-ip6tables",
1229 .maxlen = sizeof(int),
1230 .mode = 0644,
1231 .proc_handler = brnf_sysctl_call_tables,
1232 },
1233 {
1234 .procname = "bridge-nf-filter-vlan-tagged",
1235 .maxlen = sizeof(int),
1236 .mode = 0644,
1237 .proc_handler = brnf_sysctl_call_tables,
1238 },
1239 {
1240 .procname = "bridge-nf-filter-pppoe-tagged",
1241 .maxlen = sizeof(int),
1242 .mode = 0644,
1243 .proc_handler = brnf_sysctl_call_tables,
1244 },
1245 {
1246 .procname = "bridge-nf-pass-vlan-input-dev",
1247 .maxlen = sizeof(int),
1248 .mode = 0644,
1249 .proc_handler = brnf_sysctl_call_tables,
1250 },
1251 };
1252
br_netfilter_sysctl_default(struct brnf_net * brnf)1253 static inline void br_netfilter_sysctl_default(struct brnf_net *brnf)
1254 {
1255 brnf->call_iptables = 1;
1256 brnf->call_ip6tables = 1;
1257 brnf->call_arptables = 1;
1258 brnf->filter_vlan_tagged = 0;
1259 brnf->filter_pppoe_tagged = 0;
1260 brnf->pass_vlan_indev = 0;
1261 }
1262
br_netfilter_sysctl_init_net(struct net * net)1263 static int br_netfilter_sysctl_init_net(struct net *net)
1264 {
1265 struct ctl_table *table = brnf_table;
1266 struct brnf_net *brnet;
1267
1268 if (!net_eq(net, &init_net)) {
1269 table = kmemdup(table, sizeof(brnf_table), GFP_KERNEL);
1270 if (!table)
1271 return -ENOMEM;
1272 }
1273
1274 brnet = net_generic(net, brnf_net_id);
1275 table[0].data = &brnet->call_arptables;
1276 table[1].data = &brnet->call_iptables;
1277 table[2].data = &brnet->call_ip6tables;
1278 table[3].data = &brnet->filter_vlan_tagged;
1279 table[4].data = &brnet->filter_pppoe_tagged;
1280 table[5].data = &brnet->pass_vlan_indev;
1281
1282 br_netfilter_sysctl_default(brnet);
1283
1284 brnet->ctl_hdr = register_net_sysctl_sz(net, "net/bridge", table,
1285 ARRAY_SIZE(brnf_table));
1286 if (!brnet->ctl_hdr) {
1287 if (!net_eq(net, &init_net))
1288 kfree(table);
1289
1290 return -ENOMEM;
1291 }
1292
1293 return 0;
1294 }
1295
br_netfilter_sysctl_exit_net(struct net * net,struct brnf_net * brnet)1296 static void br_netfilter_sysctl_exit_net(struct net *net,
1297 struct brnf_net *brnet)
1298 {
1299 const struct ctl_table *table = brnet->ctl_hdr->ctl_table_arg;
1300
1301 unregister_net_sysctl_table(brnet->ctl_hdr);
1302 if (!net_eq(net, &init_net))
1303 kfree(table);
1304 }
1305
brnf_init_net(struct net * net)1306 static int __net_init brnf_init_net(struct net *net)
1307 {
1308 return br_netfilter_sysctl_init_net(net);
1309 }
1310 #endif
1311
brnf_exit_net(struct net * net)1312 static void __net_exit brnf_exit_net(struct net *net)
1313 {
1314 struct brnf_net *brnet;
1315
1316 brnet = net_generic(net, brnf_net_id);
1317 if (brnet->enabled) {
1318 nf_unregister_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
1319 brnet->enabled = false;
1320 }
1321
1322 #ifdef CONFIG_SYSCTL
1323 br_netfilter_sysctl_exit_net(net, brnet);
1324 #endif
1325 }
1326
1327 static struct pernet_operations brnf_net_ops __read_mostly = {
1328 #ifdef CONFIG_SYSCTL
1329 .init = brnf_init_net,
1330 #endif
1331 .exit = brnf_exit_net,
1332 .id = &brnf_net_id,
1333 .size = sizeof(struct brnf_net),
1334 };
1335
br_netfilter_init(void)1336 static int __init br_netfilter_init(void)
1337 {
1338 int ret;
1339
1340 ret = register_pernet_subsys(&brnf_net_ops);
1341 if (ret < 0)
1342 return ret;
1343
1344 ret = register_netdevice_notifier(&brnf_notifier);
1345 if (ret < 0) {
1346 unregister_pernet_subsys(&brnf_net_ops);
1347 return ret;
1348 }
1349
1350 RCU_INIT_POINTER(nf_br_ops, &br_ops);
1351 printk(KERN_NOTICE "Bridge firewalling registered\n");
1352 return 0;
1353 }
1354
br_netfilter_fini(void)1355 static void __exit br_netfilter_fini(void)
1356 {
1357 RCU_INIT_POINTER(nf_br_ops, NULL);
1358 unregister_netdevice_notifier(&brnf_notifier);
1359 unregister_pernet_subsys(&brnf_net_ops);
1360 }
1361
1362 module_init(br_netfilter_init);
1363 module_exit(br_netfilter_fini);
1364
1365 MODULE_LICENSE("GPL");
1366 MODULE_AUTHOR("Lennert Buytenhek <buytenh@gnu.org>");
1367 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
1368 MODULE_DESCRIPTION("Linux ethernet netfilter firewall bridge");
1369