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Linux 6.14-rc1
[linux.git] / net / netfilter / nfnetlink_log.c
blob134e05d31061e4b6daa977cb47084f0da20f697c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * This is a module which is used for logging packets to userspace via
4 * nfetlink.
5 *
6 * (C) 2005 by Harald Welte <laforge@netfilter.org>
7 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
8 *
9 * Based on the old ipv4-only ipt_ULOG.c:
10 * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
11 */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/module.h>
16 #include <linux/skbuff.h>
17 #include <linux/if_arp.h>
18 #include <linux/init.h>
19 #include <linux/ip.h>
20 #include <linux/ipv6.h>
21 #include <linux/netdevice.h>
22 #include <linux/netfilter.h>
23 #include <linux/netfilter_bridge.h>
24 #include <net/netlink.h>
25 #include <linux/netfilter/nfnetlink.h>
26 #include <linux/netfilter/nfnetlink_log.h>
27 #include <linux/netfilter/nf_conntrack_common.h>
28 #include <linux/spinlock.h>
29 #include <linux/sysctl.h>
30 #include <linux/proc_fs.h>
31 #include <linux/security.h>
32 #include <linux/list.h>
33 #include <linux/slab.h>
34 #include <net/sock.h>
35 #include <net/netfilter/nf_log.h>
36 #include <net/netns/generic.h>
37
38 #include <linux/atomic.h>
39 #include <linux/refcount.h>
40
41
42 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
43 #include "../bridge/br_private.h"
44 #endif
45
46 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
47 #include <net/netfilter/nf_conntrack.h>
48 #endif
49
50 #define NFULNL_COPY_DISABLED 0xff
51 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
52 #define NFULNL_TIMEOUT_DEFAULT 100 /* every second */
53 #define NFULNL_QTHRESH_DEFAULT 100 /* 100 packets */
54 /* max packet size is limited by 16-bit struct nfattr nfa_len field */
55 #define NFULNL_COPY_RANGE_MAX (0xFFFF - NLA_HDRLEN)
56
57 #define PRINTR(x, args...) do { if (net_ratelimit()) \
58 printk(x, ## args); } while (0);
59
60 struct nfulnl_instance {
61 struct hlist_node hlist; /* global list of instances */
62 spinlock_t lock;
63 refcount_t use; /* use count */
64
65 unsigned int qlen; /* number of nlmsgs in skb */
66 struct sk_buff *skb; /* pre-allocatd skb */
67 struct timer_list timer;
68 struct net *net;
69 netns_tracker ns_tracker;
70 struct user_namespace *peer_user_ns; /* User namespace of the peer process */
71 u32 peer_portid; /* PORTID of the peer process */
72
73 /* configurable parameters */
74 unsigned int flushtimeout; /* timeout until queue flush */
75 unsigned int nlbufsiz; /* netlink buffer allocation size */
76 unsigned int qthreshold; /* threshold of the queue */
77 u_int32_t copy_range;
78 u_int32_t seq; /* instance-local sequential counter */
79 u_int16_t group_num; /* number of this queue */
80 u_int16_t flags;
81 u_int8_t copy_mode;
82 struct rcu_head rcu;
83 };
84
85 #define INSTANCE_BUCKETS 16
86
87 static unsigned int nfnl_log_net_id __read_mostly;
88
89 struct nfnl_log_net {
90 spinlock_t instances_lock;
91 struct hlist_head instance_table[INSTANCE_BUCKETS];
92 atomic_t global_seq;
93 };
94
95 static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
96 {
97 return net_generic(net, nfnl_log_net_id);
98 }
99
100 static inline u_int8_t instance_hashfn(u_int16_t group_num)
101 {
102 return ((group_num & 0xff) % INSTANCE_BUCKETS);
103 }
104
105 static struct nfulnl_instance *
106 __instance_lookup(const struct nfnl_log_net *log, u16 group_num)
107 {
108 const struct hlist_head *head;
109 struct nfulnl_instance *inst;
110
111 head = &log->instance_table[instance_hashfn(group_num)];
112 hlist_for_each_entry_rcu(inst, head, hlist) {
113 if (inst->group_num == group_num)
114 return inst;
115 }
116 return NULL;
117 }
118
119 static inline void
120 instance_get(struct nfulnl_instance *inst)
121 {
122 refcount_inc(&inst->use);
123 }
124
125 static struct nfulnl_instance *
126 instance_lookup_get_rcu(const struct nfnl_log_net *log, u16 group_num)
127 {
128 struct nfulnl_instance *inst;
129
130 inst = __instance_lookup(log, group_num);
131 if (inst && !refcount_inc_not_zero(&inst->use))
132 inst = NULL;
133
134 return inst;
135 }
136
137 static struct nfulnl_instance *
138 instance_lookup_get(const struct nfnl_log_net *log, u16 group_num)
139 {
140 struct nfulnl_instance *inst;
141
142 rcu_read_lock();
143 inst = instance_lookup_get_rcu(log, group_num);
144 rcu_read_unlock();
145
146 return inst;
147 }
148
149 static void nfulnl_instance_free_rcu(struct rcu_head *head)
150 {
151 struct nfulnl_instance *inst =
152 container_of(head, struct nfulnl_instance, rcu);
153
154 put_net_track(inst->net, &inst->ns_tracker);
155 kfree(inst);
156 module_put(THIS_MODULE);
157 }
158
159 static void
160 instance_put(struct nfulnl_instance *inst)
161 {
162 if (inst && refcount_dec_and_test(&inst->use))
163 call_rcu(&inst->rcu, nfulnl_instance_free_rcu);
164 }
165
166 static void nfulnl_timer(struct timer_list *t);
167
168 static struct nfulnl_instance *
169 instance_create(struct net *net, u_int16_t group_num,
170 u32 portid, struct user_namespace *user_ns)
171 {
172 struct nfulnl_instance *inst;
173 struct nfnl_log_net *log = nfnl_log_pernet(net);
174 int err;
175
176 spin_lock_bh(&log->instances_lock);
177 if (__instance_lookup(log, group_num)) {
178 err = -EEXIST;
179 goto out_unlock;
180 }
181
182 inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
183 if (!inst) {
184 err = -ENOMEM;
185 goto out_unlock;
186 }
187
188 if (!try_module_get(THIS_MODULE)) {
189 kfree(inst);
190 err = -EAGAIN;
191 goto out_unlock;
192 }
193
194 INIT_HLIST_NODE(&inst->hlist);
195 spin_lock_init(&inst->lock);
196 /* needs to be two, since we _put() after creation */
197 refcount_set(&inst->use, 2);
198
199 timer_setup(&inst->timer, nfulnl_timer, 0);
200
201 inst->net = get_net_track(net, &inst->ns_tracker, GFP_ATOMIC);
202 inst->peer_user_ns = user_ns;
203 inst->peer_portid = portid;
204 inst->group_num = group_num;
205
206 inst->qthreshold = NFULNL_QTHRESH_DEFAULT;
207 inst->flushtimeout = NFULNL_TIMEOUT_DEFAULT;
208 inst->nlbufsiz = NFULNL_NLBUFSIZ_DEFAULT;
209 inst->copy_mode = NFULNL_COPY_PACKET;
210 inst->copy_range = NFULNL_COPY_RANGE_MAX;
211
212 hlist_add_head_rcu(&inst->hlist,
213 &log->instance_table[instance_hashfn(group_num)]);
214
215
216 spin_unlock_bh(&log->instances_lock);
217
218 return inst;
219
220 out_unlock:
221 spin_unlock_bh(&log->instances_lock);
222 return ERR_PTR(err);
223 }
224
225 static void __nfulnl_flush(struct nfulnl_instance *inst);
226
227 /* called with BH disabled */
228 static void
229 __instance_destroy(struct nfulnl_instance *inst)
230 {
231 /* first pull it out of the global list */
232 hlist_del_rcu(&inst->hlist);
233
234 /* then flush all pending packets from skb */
235
236 spin_lock(&inst->lock);
237
238 /* lockless readers wont be able to use us */
239 inst->copy_mode = NFULNL_COPY_DISABLED;
240
241 if (inst->skb)
242 __nfulnl_flush(inst);
243 spin_unlock(&inst->lock);
244
245 /* and finally put the refcount */
246 instance_put(inst);
247 }
248
249 static inline void
250 instance_destroy(struct nfnl_log_net *log,
251 struct nfulnl_instance *inst)
252 {
253 spin_lock_bh(&log->instances_lock);
254 __instance_destroy(inst);
255 spin_unlock_bh(&log->instances_lock);
256 }
257
258 static int
259 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
260 unsigned int range)
261 {
262 int status = 0;
263
264 spin_lock_bh(&inst->lock);
265
266 switch (mode) {
267 case NFULNL_COPY_NONE:
268 case NFULNL_COPY_META:
269 inst->copy_mode = mode;
270 inst->copy_range = 0;
271 break;
272
273 case NFULNL_COPY_PACKET:
274 inst->copy_mode = mode;
275 if (range == 0)
276 range = NFULNL_COPY_RANGE_MAX;
277 inst->copy_range = min_t(unsigned int,
278 range, NFULNL_COPY_RANGE_MAX);
279 break;
280
281 default:
282 status = -EINVAL;
283 break;
284 }
285
286 spin_unlock_bh(&inst->lock);
287
288 return status;
289 }
290
291 static int
292 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
293 {
294 int status;
295
296 spin_lock_bh(&inst->lock);
297 if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
298 status = -ERANGE;
299 else if (nlbufsiz > 131072)
300 status = -ERANGE;
301 else {
302 inst->nlbufsiz = nlbufsiz;
303 status = 0;
304 }
305 spin_unlock_bh(&inst->lock);
306
307 return status;
308 }
309
310 static void
311 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
312 {
313 spin_lock_bh(&inst->lock);
314 inst->flushtimeout = timeout;
315 spin_unlock_bh(&inst->lock);
316 }
317
318 static void
319 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
320 {
321 spin_lock_bh(&inst->lock);
322 inst->qthreshold = qthresh;
323 spin_unlock_bh(&inst->lock);
324 }
325
326 static int
327 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
328 {
329 spin_lock_bh(&inst->lock);
330 inst->flags = flags;
331 spin_unlock_bh(&inst->lock);
332
333 return 0;
334 }
335
336 static struct sk_buff *
337 nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
338 unsigned int pkt_size)
339 {
340 struct sk_buff *skb;
341 unsigned int n;
342
343 /* alloc skb which should be big enough for a whole multipart
344 * message. WARNING: has to be <= 128k due to slab restrictions */
345
346 n = max(inst_size, pkt_size);
347 skb = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN);
348 if (!skb) {
349 if (n > pkt_size) {
350 /* try to allocate only as much as we need for current
351 * packet */
352
353 skb = alloc_skb(pkt_size, GFP_ATOMIC);
354 }
355 }
356
357 return skb;
358 }
359
360 static void
361 __nfulnl_send(struct nfulnl_instance *inst)
362 {
363 if (inst->qlen > 1) {
364 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
365 NLMSG_DONE,
366 sizeof(struct nfgenmsg),
367 0);
368 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
369 inst->skb->len, skb_tailroom(inst->skb))) {
370 kfree_skb(inst->skb);
371 goto out;
372 }
373 }
374 nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid);
375 out:
376 inst->qlen = 0;
377 inst->skb = NULL;
378 }
379
380 static void
381 __nfulnl_flush(struct nfulnl_instance *inst)
382 {
383 /* timer holds a reference */
384 if (del_timer(&inst->timer))
385 instance_put(inst);
386 if (inst->skb)
387 __nfulnl_send(inst);
388 }
389
390 static void
391 nfulnl_timer(struct timer_list *t)
392 {
393 struct nfulnl_instance *inst = from_timer(inst, t, timer);
394
395 spin_lock_bh(&inst->lock);
396 if (inst->skb)
397 __nfulnl_send(inst);
398 spin_unlock_bh(&inst->lock);
399 instance_put(inst);
400 }
401
402 static u32 nfulnl_get_bridge_size(const struct sk_buff *skb)
403 {
404 u32 size = 0;
405
406 if (!skb_mac_header_was_set(skb))
407 return 0;
408
409 if (skb_vlan_tag_present(skb)) {
410 size += nla_total_size(0); /* nested */
411 size += nla_total_size(sizeof(u16)); /* id */
412 size += nla_total_size(sizeof(u16)); /* tag */
413 }
414
415 if (skb->network_header > skb->mac_header)
416 size += nla_total_size(skb->network_header - skb->mac_header);
417
418 return size;
419 }
420
421 static int nfulnl_put_bridge(struct nfulnl_instance *inst, const struct sk_buff *skb)
422 {
423 if (!skb_mac_header_was_set(skb))
424 return 0;
425
426 if (skb_vlan_tag_present(skb)) {
427 struct nlattr *nest;
428
429 nest = nla_nest_start(inst->skb, NFULA_VLAN);
430 if (!nest)
431 goto nla_put_failure;
432
433 if (nla_put_be16(inst->skb, NFULA_VLAN_TCI, htons(skb->vlan_tci)) ||
434 nla_put_be16(inst->skb, NFULA_VLAN_PROTO, skb->vlan_proto))
435 goto nla_put_failure;
436
437 nla_nest_end(inst->skb, nest);
438 }
439
440 if (skb->mac_header < skb->network_header) {
441 int len = (int)(skb->network_header - skb->mac_header);
442
443 if (nla_put(inst->skb, NFULA_L2HDR, len, skb_mac_header(skb)))
444 goto nla_put_failure;
445 }
446
447 return 0;
448
449 nla_put_failure:
450 return -1;
451 }
452
453 /* This is an inline function, we don't really care about a long
454 * list of arguments */
455 static inline int
456 __build_packet_message(struct nfnl_log_net *log,
457 struct nfulnl_instance *inst,
458 const struct sk_buff *skb,
459 unsigned int data_len,
460 u_int8_t pf,
461 unsigned int hooknum,
462 const struct net_device *indev,
463 const struct net_device *outdev,
464 const char *prefix, unsigned int plen,
465 const struct nfnl_ct_hook *nfnl_ct,
466 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
467 {
468 struct nfulnl_msg_packet_hdr pmsg;
469 struct nlmsghdr *nlh;
470 sk_buff_data_t old_tail = inst->skb->tail;
471 struct sock *sk;
472 const unsigned char *hwhdrp;
473
474 nlh = nfnl_msg_put(inst->skb, 0, 0,
475 nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET),
476 0, pf, NFNETLINK_V0, htons(inst->group_num));
477 if (!nlh)
478 return -1;
479
480 memset(&pmsg, 0, sizeof(pmsg));
481 pmsg.hw_protocol = skb->protocol;
482 pmsg.hook = hooknum;
483
484 if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
485 goto nla_put_failure;
486
487 if (prefix &&
488 nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
489 goto nla_put_failure;
490
491 if (indev) {
492 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
493 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
494 htonl(indev->ifindex)))
495 goto nla_put_failure;
496 #else
497 if (pf == PF_BRIDGE) {
498 /* Case 1: outdev is physical input device, we need to
499 * look for bridge group (when called from
500 * netfilter_bridge) */
501 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
502 htonl(indev->ifindex)) ||
503 /* this is the bridge group "brX" */
504 /* rcu_read_lock()ed by nf_hook_thresh or
505 * nf_log_packet.
506 */
507 nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
508 htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
509 goto nla_put_failure;
510 } else {
511 int physinif;
512
513 /* Case 2: indev is bridge group, we need to look for
514 * physical device (when called from ipv4) */
515 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
516 htonl(indev->ifindex)))
517 goto nla_put_failure;
518
519 physinif = nf_bridge_get_physinif(skb);
520 if (physinif &&
521 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
522 htonl(physinif)))
523 goto nla_put_failure;
524 }
525 #endif
526 }
527
528 if (outdev) {
529 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
530 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
531 htonl(outdev->ifindex)))
532 goto nla_put_failure;
533 #else
534 if (pf == PF_BRIDGE) {
535 /* Case 1: outdev is physical output device, we need to
536 * look for bridge group (when called from
537 * netfilter_bridge) */
538 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
539 htonl(outdev->ifindex)) ||
540 /* this is the bridge group "brX" */
541 /* rcu_read_lock()ed by nf_hook_thresh or
542 * nf_log_packet.
543 */
544 nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
545 htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
546 goto nla_put_failure;
547 } else {
548 struct net_device *physoutdev;
549
550 /* Case 2: indev is a bridge group, we need to look
551 * for physical device (when called from ipv4) */
552 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
553 htonl(outdev->ifindex)))
554 goto nla_put_failure;
555
556 physoutdev = nf_bridge_get_physoutdev(skb);
557 if (physoutdev &&
558 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
559 htonl(physoutdev->ifindex)))
560 goto nla_put_failure;
561 }
562 #endif
563 }
564
565 if (skb->mark &&
566 nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
567 goto nla_put_failure;
568
569 if (indev && skb->dev &&
570 skb_mac_header_was_set(skb) &&
571 skb_mac_header_len(skb) != 0) {
572 struct nfulnl_msg_packet_hw phw;
573 int len;
574
575 memset(&phw, 0, sizeof(phw));
576 len = dev_parse_header(skb, phw.hw_addr);
577 if (len > 0) {
578 phw.hw_addrlen = htons(len);
579 if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
580 goto nla_put_failure;
581 }
582 }
583
584 if (indev && skb_mac_header_was_set(skb)) {
585 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
586 nla_put_be16(inst->skb, NFULA_HWLEN,
587 htons(skb->dev->hard_header_len)))
588 goto nla_put_failure;
589
590 hwhdrp = skb_mac_header(skb);
591
592 if (skb->dev->type == ARPHRD_SIT)
593 hwhdrp -= ETH_HLEN;
594
595 if (hwhdrp >= skb->head &&
596 nla_put(inst->skb, NFULA_HWHEADER,
597 skb->dev->hard_header_len, hwhdrp))
598 goto nla_put_failure;
599 }
600
601 if (hooknum <= NF_INET_FORWARD) {
602 struct timespec64 kts = ktime_to_timespec64(skb_tstamp_cond(skb, true));
603 struct nfulnl_msg_packet_timestamp ts;
604 ts.sec = cpu_to_be64(kts.tv_sec);
605 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
606
607 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
608 goto nla_put_failure;
609 }
610
611 /* UID */
612 sk = skb->sk;
613 if (sk && sk_fullsock(sk)) {
614 read_lock_bh(&sk->sk_callback_lock);
615 if (sk->sk_socket && sk->sk_socket->file) {
616 struct file *file = sk->sk_socket->file;
617 const struct cred *cred = file->f_cred;
618 struct user_namespace *user_ns = inst->peer_user_ns;
619 __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
620 __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
621 read_unlock_bh(&sk->sk_callback_lock);
622 if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
623 nla_put_be32(inst->skb, NFULA_GID, gid))
624 goto nla_put_failure;
625 } else
626 read_unlock_bh(&sk->sk_callback_lock);
627 }
628
629 /* local sequence number */
630 if ((inst->flags & NFULNL_CFG_F_SEQ) &&
631 nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
632 goto nla_put_failure;
633
634 /* global sequence number */
635 if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
636 nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
637 htonl(atomic_inc_return(&log->global_seq))))
638 goto nla_put_failure;
639
640 if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
641 NFULA_CT, NFULA_CT_INFO) < 0)
642 goto nla_put_failure;
643
644 if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) &&
645 nfulnl_put_bridge(inst, skb) < 0)
646 goto nla_put_failure;
647
648 if (data_len) {
649 struct nlattr *nla;
650 int size = nla_attr_size(data_len);
651
652 if (skb_tailroom(inst->skb) < nla_total_size(data_len))
653 goto nla_put_failure;
654
655 nla = skb_put(inst->skb, nla_total_size(data_len));
656 nla->nla_type = NFULA_PAYLOAD;
657 nla->nla_len = size;
658
659 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
660 BUG();
661 }
662
663 nlh->nlmsg_len = inst->skb->tail - old_tail;
664 return 0;
665
666 nla_put_failure:
667 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
668 return -1;
669 }
670
671 static const struct nf_loginfo default_loginfo = {
672 .type = NF_LOG_TYPE_ULOG,
673 .u = {
674 .ulog = {
675 .copy_len = 0xffff,
676 .group = 0,
677 .qthreshold = 1,
678 },
679 },
680 };
681
682 /* log handler for internal netfilter logging api */
683 static void
684 nfulnl_log_packet(struct net *net,
685 u_int8_t pf,
686 unsigned int hooknum,
687 const struct sk_buff *skb,
688 const struct net_device *in,
689 const struct net_device *out,
690 const struct nf_loginfo *li_user,
691 const char *prefix)
692 {
693 size_t size;
694 unsigned int data_len;
695 struct nfulnl_instance *inst;
696 const struct nf_loginfo *li;
697 unsigned int qthreshold;
698 unsigned int plen = 0;
699 struct nfnl_log_net *log = nfnl_log_pernet(net);
700 const struct nfnl_ct_hook *nfnl_ct = NULL;
701 enum ip_conntrack_info ctinfo = 0;
702 struct nf_conn *ct = NULL;
703
704 if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
705 li = li_user;
706 else
707 li = &default_loginfo;
708
709 inst = instance_lookup_get_rcu(log, li->u.ulog.group);
710 if (!inst)
711 return;
712
713 if (prefix)
714 plen = strlen(prefix) + 1;
715
716 /* FIXME: do we want to make the size calculation conditional based on
717 * what is actually present? way more branches and checks, but more
718 * memory efficient... */
719 size = nlmsg_total_size(sizeof(struct nfgenmsg))
720 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
721 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
722 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
723 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
724 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
725 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
726 #endif
727 + nla_total_size(sizeof(u_int32_t)) /* mark */
728 + nla_total_size(sizeof(u_int32_t)) /* uid */
729 + nla_total_size(sizeof(u_int32_t)) /* gid */
730 + nla_total_size(plen) /* prefix */
731 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
732 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
733 + nla_total_size(sizeof(struct nfgenmsg)); /* NLMSG_DONE */
734
735 if (in && skb_mac_header_was_set(skb)) {
736 size += nla_total_size(skb->dev->hard_header_len)
737 + nla_total_size(sizeof(u_int16_t)) /* hwtype */
738 + nla_total_size(sizeof(u_int16_t)); /* hwlen */
739 }
740
741 spin_lock_bh(&inst->lock);
742
743 if (inst->flags & NFULNL_CFG_F_SEQ)
744 size += nla_total_size(sizeof(u_int32_t));
745 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
746 size += nla_total_size(sizeof(u_int32_t));
747 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
748 if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
749 nfnl_ct = rcu_dereference(nfnl_ct_hook);
750 if (nfnl_ct != NULL) {
751 ct = nf_ct_get(skb, &ctinfo);
752 if (ct != NULL)
753 size += nfnl_ct->build_size(ct);
754 }
755 }
756 #endif
757 if (pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE)
758 size += nfulnl_get_bridge_size(skb);
759
760 qthreshold = inst->qthreshold;
761 /* per-rule qthreshold overrides per-instance */
762 if (li->u.ulog.qthreshold)
763 if (qthreshold > li->u.ulog.qthreshold)
764 qthreshold = li->u.ulog.qthreshold;
765
766
767 switch (inst->copy_mode) {
768 case NFULNL_COPY_META:
769 case NFULNL_COPY_NONE:
770 data_len = 0;
771 break;
772
773 case NFULNL_COPY_PACKET:
774 data_len = inst->copy_range;
775 if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) &&
776 (li->u.ulog.copy_len < data_len))
777 data_len = li->u.ulog.copy_len;
778
779 if (data_len > skb->len)
780 data_len = skb->len;
781
782 size += nla_total_size(data_len);
783 break;
784
785 case NFULNL_COPY_DISABLED:
786 default:
787 goto unlock_and_release;
788 }
789
790 if (inst->skb && size > skb_tailroom(inst->skb)) {
791 /* either the queue len is too high or we don't have
792 * enough room in the skb left. flush to userspace. */
793 __nfulnl_flush(inst);
794 }
795
796 if (!inst->skb) {
797 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
798 inst->nlbufsiz, size);
799 if (!inst->skb)
800 goto alloc_failure;
801 }
802
803 inst->qlen++;
804
805 __build_packet_message(log, inst, skb, data_len, pf,
806 hooknum, in, out, prefix, plen,
807 nfnl_ct, ct, ctinfo);
808
809 if (inst->qlen >= qthreshold)
810 __nfulnl_flush(inst);
811 /* timer_pending always called within inst->lock, so there
812 * is no chance of a race here */
813 else if (!timer_pending(&inst->timer)) {
814 instance_get(inst);
815 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
816 add_timer(&inst->timer);
817 }
818
819 unlock_and_release:
820 spin_unlock_bh(&inst->lock);
821 instance_put(inst);
822 return;
823
824 alloc_failure:
825 /* FIXME: statistics */
826 goto unlock_and_release;
827 }
828
829 static int
830 nfulnl_rcv_nl_event(struct notifier_block *this,
831 unsigned long event, void *ptr)
832 {
833 struct netlink_notify *n = ptr;
834 struct nfnl_log_net *log = nfnl_log_pernet(n->net);
835
836 if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
837 int i;
838
839 /* destroy all instances for this portid */
840 spin_lock_bh(&log->instances_lock);
841 for (i = 0; i < INSTANCE_BUCKETS; i++) {
842 struct hlist_node *t2;
843 struct nfulnl_instance *inst;
844 struct hlist_head *head = &log->instance_table[i];
845
846 hlist_for_each_entry_safe(inst, t2, head, hlist) {
847 if (n->portid == inst->peer_portid)
848 __instance_destroy(inst);
849 }
850 }
851 spin_unlock_bh(&log->instances_lock);
852 }
853 return NOTIFY_DONE;
854 }
855
856 static struct notifier_block nfulnl_rtnl_notifier = {
857 .notifier_call = nfulnl_rcv_nl_event,
858 };
859
860 static int nfulnl_recv_unsupp(struct sk_buff *skb, const struct nfnl_info *info,
861 const struct nlattr * const nfula[])
862 {
863 return -ENOTSUPP;
864 }
865
866 static struct nf_logger nfulnl_logger __read_mostly = {
867 .name = "nfnetlink_log",
868 .type = NF_LOG_TYPE_ULOG,
869 .logfn = nfulnl_log_packet,
870 .me = THIS_MODULE,
871 };
872
873 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
874 [NFULA_CFG_CMD] = { .len = sizeof(struct nfulnl_msg_config_cmd) },
875 [NFULA_CFG_MODE] = { .len = sizeof(struct nfulnl_msg_config_mode) },
876 [NFULA_CFG_TIMEOUT] = { .type = NLA_U32 },
877 [NFULA_CFG_QTHRESH] = { .type = NLA_U32 },
878 [NFULA_CFG_NLBUFSIZ] = { .type = NLA_U32 },
879 [NFULA_CFG_FLAGS] = { .type = NLA_U16 },
880 };
881
882 static int nfulnl_recv_config(struct sk_buff *skb, const struct nfnl_info *info,
883 const struct nlattr * const nfula[])
884 {
885 struct nfnl_log_net *log = nfnl_log_pernet(info->net);
886 u_int16_t group_num = ntohs(info->nfmsg->res_id);
887 struct nfulnl_msg_config_cmd *cmd = NULL;
888 struct nfulnl_instance *inst;
889 u16 flags = 0;
890 int ret = 0;
891
892 if (nfula[NFULA_CFG_CMD]) {
893 u_int8_t pf = info->nfmsg->nfgen_family;
894 cmd = nla_data(nfula[NFULA_CFG_CMD]);
895
896 /* Commands without queue context */
897 switch (cmd->command) {
898 case NFULNL_CFG_CMD_PF_BIND:
899 return nf_log_bind_pf(info->net, pf, &nfulnl_logger);
900 case NFULNL_CFG_CMD_PF_UNBIND:
901 nf_log_unbind_pf(info->net, pf);
902 return 0;
903 }
904 }
905
906 inst = instance_lookup_get(log, group_num);
907 if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
908 ret = -EPERM;
909 goto out_put;
910 }
911
912 /* Check if we support these flags in first place, dependencies should
913 * be there too not to break atomicity.
914 */
915 if (nfula[NFULA_CFG_FLAGS]) {
916 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
917
918 if ((flags & NFULNL_CFG_F_CONNTRACK) &&
919 !rcu_access_pointer(nfnl_ct_hook)) {
920 #ifdef CONFIG_MODULES
921 nfnl_unlock(NFNL_SUBSYS_ULOG);
922 request_module("ip_conntrack_netlink");
923 nfnl_lock(NFNL_SUBSYS_ULOG);
924 if (rcu_access_pointer(nfnl_ct_hook)) {
925 ret = -EAGAIN;
926 goto out_put;
927 }
928 #endif
929 ret = -EOPNOTSUPP;
930 goto out_put;
931 }
932 }
933
934 if (cmd != NULL) {
935 switch (cmd->command) {
936 case NFULNL_CFG_CMD_BIND:
937 if (inst) {
938 ret = -EBUSY;
939 goto out_put;
940 }
941
942 inst = instance_create(info->net, group_num,
943 NETLINK_CB(skb).portid,
944 sk_user_ns(NETLINK_CB(skb).sk));
945 if (IS_ERR(inst)) {
946 ret = PTR_ERR(inst);
947 goto out;
948 }
949 break;
950 case NFULNL_CFG_CMD_UNBIND:
951 if (!inst) {
952 ret = -ENODEV;
953 goto out;
954 }
955
956 instance_destroy(log, inst);
957 goto out_put;
958 default:
959 ret = -ENOTSUPP;
960 goto out_put;
961 }
962 } else if (!inst) {
963 ret = -ENODEV;
964 goto out;
965 }
966
967 if (nfula[NFULA_CFG_MODE]) {
968 struct nfulnl_msg_config_mode *params =
969 nla_data(nfula[NFULA_CFG_MODE]);
970
971 nfulnl_set_mode(inst, params->copy_mode,
972 ntohl(params->copy_range));
973 }
974
975 if (nfula[NFULA_CFG_TIMEOUT]) {
976 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
977
978 nfulnl_set_timeout(inst, ntohl(timeout));
979 }
980
981 if (nfula[NFULA_CFG_NLBUFSIZ]) {
982 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
983
984 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
985 }
986
987 if (nfula[NFULA_CFG_QTHRESH]) {
988 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
989
990 nfulnl_set_qthresh(inst, ntohl(qthresh));
991 }
992
993 if (nfula[NFULA_CFG_FLAGS])
994 nfulnl_set_flags(inst, flags);
995
996 out_put:
997 instance_put(inst);
998 out:
999 return ret;
1000 }
1001
1002 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
1003 [NFULNL_MSG_PACKET] = {
1004 .call = nfulnl_recv_unsupp,
1005 .type = NFNL_CB_MUTEX,
1006 .attr_count = NFULA_MAX,
1007 },
1008 [NFULNL_MSG_CONFIG] = {
1009 .call = nfulnl_recv_config,
1010 .type = NFNL_CB_MUTEX,
1011 .attr_count = NFULA_CFG_MAX,
1012 .policy = nfula_cfg_policy
1013 },
1014 };
1015
1016 static const struct nfnetlink_subsystem nfulnl_subsys = {
1017 .name = "log",
1018 .subsys_id = NFNL_SUBSYS_ULOG,
1019 .cb_count = NFULNL_MSG_MAX,
1020 .cb = nfulnl_cb,
1021 };
1022
1023 #ifdef CONFIG_PROC_FS
1024 struct iter_state {
1025 struct seq_net_private p;
1026 unsigned int bucket;
1027 };
1028
1029 static struct hlist_node *get_first(struct net *net, struct iter_state *st)
1030 {
1031 struct nfnl_log_net *log;
1032 if (!st)
1033 return NULL;
1034
1035 log = nfnl_log_pernet(net);
1036
1037 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
1038 struct hlist_head *head = &log->instance_table[st->bucket];
1039
1040 if (!hlist_empty(head))
1041 return rcu_dereference(hlist_first_rcu(head));
1042 }
1043 return NULL;
1044 }
1045
1046 static struct hlist_node *get_next(struct net *net, struct iter_state *st,
1047 struct hlist_node *h)
1048 {
1049 h = rcu_dereference(hlist_next_rcu(h));
1050 while (!h) {
1051 struct nfnl_log_net *log;
1052 struct hlist_head *head;
1053
1054 if (++st->bucket >= INSTANCE_BUCKETS)
1055 return NULL;
1056
1057 log = nfnl_log_pernet(net);
1058 head = &log->instance_table[st->bucket];
1059 h = rcu_dereference(hlist_first_rcu(head));
1060 }
1061 return h;
1062 }
1063
1064 static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
1065 loff_t pos)
1066 {
1067 struct hlist_node *head;
1068 head = get_first(net, st);
1069
1070 if (head)
1071 while (pos && (head = get_next(net, st, head)))
1072 pos--;
1073 return pos ? NULL : head;
1074 }
1075
1076 static void *seq_start(struct seq_file *s, loff_t *pos)
1077 __acquires(rcu)
1078 {
1079 rcu_read_lock();
1080 return get_idx(seq_file_net(s), s->private, *pos);
1081 }
1082
1083 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
1084 {
1085 (*pos)++;
1086 return get_next(seq_file_net(s), s->private, v);
1087 }
1088
1089 static void seq_stop(struct seq_file *s, void *v)
1090 __releases(rcu)
1091 {
1092 rcu_read_unlock();
1093 }
1094
1095 static int seq_show(struct seq_file *s, void *v)
1096 {
1097 const struct nfulnl_instance *inst = v;
1098
1099 seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1100 inst->group_num,
1101 inst->peer_portid, inst->qlen,
1102 inst->copy_mode, inst->copy_range,
1103 inst->flushtimeout, refcount_read(&inst->use));
1104
1105 return 0;
1106 }
1107
1108 static const struct seq_operations nful_seq_ops = {
1109 .start = seq_start,
1110 .next = seq_next,
1111 .stop = seq_stop,
1112 .show = seq_show,
1113 };
1114 #endif /* PROC_FS */
1115
1116 static int __net_init nfnl_log_net_init(struct net *net)
1117 {
1118 unsigned int i;
1119 struct nfnl_log_net *log = nfnl_log_pernet(net);
1120 #ifdef CONFIG_PROC_FS
1121 struct proc_dir_entry *proc;
1122 kuid_t root_uid;
1123 kgid_t root_gid;
1124 #endif
1125
1126 for (i = 0; i < INSTANCE_BUCKETS; i++)
1127 INIT_HLIST_HEAD(&log->instance_table[i]);
1128 spin_lock_init(&log->instances_lock);
1129
1130 #ifdef CONFIG_PROC_FS
1131 proc = proc_create_net("nfnetlink_log", 0440, net->nf.proc_netfilter,
1132 &nful_seq_ops, sizeof(struct iter_state));
1133 if (!proc)
1134 return -ENOMEM;
1135
1136 root_uid = make_kuid(net->user_ns, 0);
1137 root_gid = make_kgid(net->user_ns, 0);
1138 if (uid_valid(root_uid) && gid_valid(root_gid))
1139 proc_set_user(proc, root_uid, root_gid);
1140 #endif
1141 return 0;
1142 }
1143
1144 static void __net_exit nfnl_log_net_exit(struct net *net)
1145 {
1146 struct nfnl_log_net *log = nfnl_log_pernet(net);
1147 unsigned int i;
1148
1149 #ifdef CONFIG_PROC_FS
1150 remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1151 #endif
1152 nf_log_unset(net, &nfulnl_logger);
1153 for (i = 0; i < INSTANCE_BUCKETS; i++)
1154 WARN_ON_ONCE(!hlist_empty(&log->instance_table[i]));
1155 }
1156
1157 static struct pernet_operations nfnl_log_net_ops = {
1158 .init = nfnl_log_net_init,
1159 .exit = nfnl_log_net_exit,
1160 .id = &nfnl_log_net_id,
1161 .size = sizeof(struct nfnl_log_net),
1162 };
1163
1164 static int __init nfnetlink_log_init(void)
1165 {
1166 int status;
1167
1168 status = register_pernet_subsys(&nfnl_log_net_ops);
1169 if (status < 0) {
1170 pr_err("failed to register pernet ops\n");
1171 goto out;
1172 }
1173
1174 netlink_register_notifier(&nfulnl_rtnl_notifier);
1175 status = nfnetlink_subsys_register(&nfulnl_subsys);
1176 if (status < 0) {
1177 pr_err("failed to create netlink socket\n");
1178 goto cleanup_netlink_notifier;
1179 }
1180
1181 status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1182 if (status < 0) {
1183 pr_err("failed to register logger\n");
1184 goto cleanup_subsys;
1185 }
1186
1187 return status;
1188
1189 cleanup_subsys:
1190 nfnetlink_subsys_unregister(&nfulnl_subsys);
1191 cleanup_netlink_notifier:
1192 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1193 unregister_pernet_subsys(&nfnl_log_net_ops);
1194 out:
1195 return status;
1196 }
1197
1198 static void __exit nfnetlink_log_fini(void)
1199 {
1200 nfnetlink_subsys_unregister(&nfulnl_subsys);
1201 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1202 unregister_pernet_subsys(&nfnl_log_net_ops);
1203 nf_log_unregister(&nfulnl_logger);
1204 }
1205
1206 MODULE_DESCRIPTION("netfilter userspace logging");
1207 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1208 MODULE_LICENSE("GPL");
1209 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1210 MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1211 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1212 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1213 MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */
1214 MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */
1215
1216 module_init(nfnetlink_log_init);
1217 module_exit(nfnetlink_log_fini);
Linux Kernel