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[mirror_ubuntu-bionic-kernel.git] / net / netfilter / nfnetlink_log.c
1 /*
2 * This is a module which is used for logging packets to userspace via
3 * nfetlink.
4 *
5 * (C) 2005 by Harald Welte <laforge@netfilter.org>
6 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
7 *
8 * Based on the old ipv4-only ipt_ULOG.c:
9 * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
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 <net/netlink.h>
24 #include <linux/netfilter/nfnetlink.h>
25 #include <linux/netfilter/nfnetlink_log.h>
26 #include <linux/spinlock.h>
27 #include <linux/sysctl.h>
28 #include <linux/proc_fs.h>
29 #include <linux/security.h>
30 #include <linux/list.h>
31 #include <linux/jhash.h>
32 #include <linux/random.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 #include <net/netfilter/nfnetlink_log.h>
38
39 #include <linux/atomic.h>
40
41 #ifdef CONFIG_BRIDGE_NETFILTER
42 #include "../bridge/br_private.h"
43 #endif
44
45 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
46 #define NFULNL_TIMEOUT_DEFAULT 100 /* every second */
47 #define NFULNL_QTHRESH_DEFAULT 100 /* 100 packets */
48 #define NFULNL_COPY_RANGE_MAX 0xFFFF /* max packet size is limited by 16-bit struct nfattr nfa_len field */
49
50 #define PRINTR(x, args...) do { if (net_ratelimit()) \
51 printk(x, ## args); } while (0);
52
53 struct nfulnl_instance {
54 struct hlist_node hlist; /* global list of instances */
55 spinlock_t lock;
56 atomic_t use; /* use count */
57
58 unsigned int qlen; /* number of nlmsgs in skb */
59 struct sk_buff *skb; /* pre-allocatd skb */
60 struct timer_list timer;
61 struct net *net;
62 struct user_namespace *peer_user_ns; /* User namespace of the peer process */
63 int peer_portid; /* PORTID of the peer process */
64
65 /* configurable parameters */
66 unsigned int flushtimeout; /* timeout until queue flush */
67 unsigned int nlbufsiz; /* netlink buffer allocation size */
68 unsigned int qthreshold; /* threshold of the queue */
69 u_int32_t copy_range;
70 u_int32_t seq; /* instance-local sequential counter */
71 u_int16_t group_num; /* number of this queue */
72 u_int16_t flags;
73 u_int8_t copy_mode;
74 struct rcu_head rcu;
75 };
76
77 #define INSTANCE_BUCKETS 16
78 static unsigned int hash_init;
79
80 static int nfnl_log_net_id __read_mostly;
81
82 struct nfnl_log_net {
83 spinlock_t instances_lock;
84 struct hlist_head instance_table[INSTANCE_BUCKETS];
85 atomic_t global_seq;
86 };
87
88 static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
89 {
90 return net_generic(net, nfnl_log_net_id);
91 }
92
93 static inline u_int8_t instance_hashfn(u_int16_t group_num)
94 {
95 return ((group_num & 0xff) % INSTANCE_BUCKETS);
96 }
97
98 static struct nfulnl_instance *
99 __instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
100 {
101 struct hlist_head *head;
102 struct nfulnl_instance *inst;
103
104 head = &log->instance_table[instance_hashfn(group_num)];
105 hlist_for_each_entry_rcu(inst, head, hlist) {
106 if (inst->group_num == group_num)
107 return inst;
108 }
109 return NULL;
110 }
111
112 static inline void
113 instance_get(struct nfulnl_instance *inst)
114 {
115 atomic_inc(&inst->use);
116 }
117
118 static struct nfulnl_instance *
119 instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
120 {
121 struct nfulnl_instance *inst;
122
123 rcu_read_lock_bh();
124 inst = __instance_lookup(log, group_num);
125 if (inst && !atomic_inc_not_zero(&inst->use))
126 inst = NULL;
127 rcu_read_unlock_bh();
128
129 return inst;
130 }
131
132 static void nfulnl_instance_free_rcu(struct rcu_head *head)
133 {
134 struct nfulnl_instance *inst =
135 container_of(head, struct nfulnl_instance, rcu);
136
137 put_net(inst->net);
138 kfree(inst);
139 module_put(THIS_MODULE);
140 }
141
142 static void
143 instance_put(struct nfulnl_instance *inst)
144 {
145 if (inst && atomic_dec_and_test(&inst->use))
146 call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
147 }
148
149 static void nfulnl_timer(unsigned long data);
150
151 static struct nfulnl_instance *
152 instance_create(struct net *net, u_int16_t group_num,
153 int portid, struct user_namespace *user_ns)
154 {
155 struct nfulnl_instance *inst;
156 struct nfnl_log_net *log = nfnl_log_pernet(net);
157 int err;
158
159 spin_lock_bh(&log->instances_lock);
160 if (__instance_lookup(log, group_num)) {
161 err = -EEXIST;
162 goto out_unlock;
163 }
164
165 inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
166 if (!inst) {
167 err = -ENOMEM;
168 goto out_unlock;
169 }
170
171 if (!try_module_get(THIS_MODULE)) {
172 kfree(inst);
173 err = -EAGAIN;
174 goto out_unlock;
175 }
176
177 INIT_HLIST_NODE(&inst->hlist);
178 spin_lock_init(&inst->lock);
179 /* needs to be two, since we _put() after creation */
180 atomic_set(&inst->use, 2);
181
182 setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
183
184 inst->net = get_net(net);
185 inst->peer_user_ns = user_ns;
186 inst->peer_portid = portid;
187 inst->group_num = group_num;
188
189 inst->qthreshold = NFULNL_QTHRESH_DEFAULT;
190 inst->flushtimeout = NFULNL_TIMEOUT_DEFAULT;
191 inst->nlbufsiz = NFULNL_NLBUFSIZ_DEFAULT;
192 inst->copy_mode = NFULNL_COPY_PACKET;
193 inst->copy_range = NFULNL_COPY_RANGE_MAX;
194
195 hlist_add_head_rcu(&inst->hlist,
196 &log->instance_table[instance_hashfn(group_num)]);
197
198
199 spin_unlock_bh(&log->instances_lock);
200
201 return inst;
202
203 out_unlock:
204 spin_unlock_bh(&log->instances_lock);
205 return ERR_PTR(err);
206 }
207
208 static void __nfulnl_flush(struct nfulnl_instance *inst);
209
210 /* called with BH disabled */
211 static void
212 __instance_destroy(struct nfulnl_instance *inst)
213 {
214 /* first pull it out of the global list */
215 hlist_del_rcu(&inst->hlist);
216
217 /* then flush all pending packets from skb */
218
219 spin_lock(&inst->lock);
220
221 /* lockless readers wont be able to use us */
222 inst->copy_mode = NFULNL_COPY_DISABLED;
223
224 if (inst->skb)
225 __nfulnl_flush(inst);
226 spin_unlock(&inst->lock);
227
228 /* and finally put the refcount */
229 instance_put(inst);
230 }
231
232 static inline void
233 instance_destroy(struct nfnl_log_net *log,
234 struct nfulnl_instance *inst)
235 {
236 spin_lock_bh(&log->instances_lock);
237 __instance_destroy(inst);
238 spin_unlock_bh(&log->instances_lock);
239 }
240
241 static int
242 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
243 unsigned int range)
244 {
245 int status = 0;
246
247 spin_lock_bh(&inst->lock);
248
249 switch (mode) {
250 case NFULNL_COPY_NONE:
251 case NFULNL_COPY_META:
252 inst->copy_mode = mode;
253 inst->copy_range = 0;
254 break;
255
256 case NFULNL_COPY_PACKET:
257 inst->copy_mode = mode;
258 inst->copy_range = min_t(unsigned int,
259 range, NFULNL_COPY_RANGE_MAX);
260 break;
261
262 default:
263 status = -EINVAL;
264 break;
265 }
266
267 spin_unlock_bh(&inst->lock);
268
269 return status;
270 }
271
272 static int
273 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
274 {
275 int status;
276
277 spin_lock_bh(&inst->lock);
278 if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
279 status = -ERANGE;
280 else if (nlbufsiz > 131072)
281 status = -ERANGE;
282 else {
283 inst->nlbufsiz = nlbufsiz;
284 status = 0;
285 }
286 spin_unlock_bh(&inst->lock);
287
288 return status;
289 }
290
291 static int
292 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
293 {
294 spin_lock_bh(&inst->lock);
295 inst->flushtimeout = timeout;
296 spin_unlock_bh(&inst->lock);
297
298 return 0;
299 }
300
301 static int
302 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
303 {
304 spin_lock_bh(&inst->lock);
305 inst->qthreshold = qthresh;
306 spin_unlock_bh(&inst->lock);
307
308 return 0;
309 }
310
311 static int
312 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
313 {
314 spin_lock_bh(&inst->lock);
315 inst->flags = flags;
316 spin_unlock_bh(&inst->lock);
317
318 return 0;
319 }
320
321 static struct sk_buff *
322 nfulnl_alloc_skb(u32 peer_portid, unsigned int inst_size, unsigned int pkt_size)
323 {
324 struct sk_buff *skb;
325 unsigned int n;
326
327 /* alloc skb which should be big enough for a whole multipart
328 * message. WARNING: has to be <= 128k due to slab restrictions */
329
330 n = max(inst_size, pkt_size);
331 skb = nfnetlink_alloc_skb(&init_net, n, peer_portid, GFP_ATOMIC);
332 if (!skb) {
333 if (n > pkt_size) {
334 /* try to allocate only as much as we need for current
335 * packet */
336
337 skb = nfnetlink_alloc_skb(&init_net, pkt_size,
338 peer_portid, GFP_ATOMIC);
339 if (!skb)
340 pr_err("nfnetlink_log: can't even alloc %u bytes\n",
341 pkt_size);
342 }
343 }
344
345 return skb;
346 }
347
348 static int
349 __nfulnl_send(struct nfulnl_instance *inst)
350 {
351 int status = -1;
352
353 if (inst->qlen > 1) {
354 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
355 NLMSG_DONE,
356 sizeof(struct nfgenmsg),
357 0);
358 if (!nlh)
359 goto out;
360 }
361 status = nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
362 MSG_DONTWAIT);
363
364 inst->qlen = 0;
365 inst->skb = NULL;
366 out:
367 return status;
368 }
369
370 static void
371 __nfulnl_flush(struct nfulnl_instance *inst)
372 {
373 /* timer holds a reference */
374 if (del_timer(&inst->timer))
375 instance_put(inst);
376 if (inst->skb)
377 __nfulnl_send(inst);
378 }
379
380 static void
381 nfulnl_timer(unsigned long data)
382 {
383 struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
384
385 spin_lock_bh(&inst->lock);
386 if (inst->skb)
387 __nfulnl_send(inst);
388 spin_unlock_bh(&inst->lock);
389 instance_put(inst);
390 }
391
392 /* This is an inline function, we don't really care about a long
393 * list of arguments */
394 static inline int
395 __build_packet_message(struct nfnl_log_net *log,
396 struct nfulnl_instance *inst,
397 const struct sk_buff *skb,
398 unsigned int data_len,
399 u_int8_t pf,
400 unsigned int hooknum,
401 const struct net_device *indev,
402 const struct net_device *outdev,
403 const char *prefix, unsigned int plen)
404 {
405 struct nfulnl_msg_packet_hdr pmsg;
406 struct nlmsghdr *nlh;
407 struct nfgenmsg *nfmsg;
408 sk_buff_data_t old_tail = inst->skb->tail;
409 struct sock *sk;
410 const unsigned char *hwhdrp;
411
412 nlh = nlmsg_put(inst->skb, 0, 0,
413 NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
414 sizeof(struct nfgenmsg), 0);
415 if (!nlh)
416 return -1;
417 nfmsg = nlmsg_data(nlh);
418 nfmsg->nfgen_family = pf;
419 nfmsg->version = NFNETLINK_V0;
420 nfmsg->res_id = htons(inst->group_num);
421
422 memset(&pmsg, 0, sizeof(pmsg));
423 pmsg.hw_protocol = skb->protocol;
424 pmsg.hook = hooknum;
425
426 if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
427 goto nla_put_failure;
428
429 if (prefix &&
430 nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
431 goto nla_put_failure;
432
433 if (indev) {
434 #ifndef CONFIG_BRIDGE_NETFILTER
435 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
436 htonl(indev->ifindex)))
437 goto nla_put_failure;
438 #else
439 if (pf == PF_BRIDGE) {
440 /* Case 1: outdev is physical input device, we need to
441 * look for bridge group (when called from
442 * netfilter_bridge) */
443 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
444 htonl(indev->ifindex)) ||
445 /* this is the bridge group "brX" */
446 /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
447 nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
448 htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
449 goto nla_put_failure;
450 } else {
451 /* Case 2: indev is bridge group, we need to look for
452 * physical device (when called from ipv4) */
453 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
454 htonl(indev->ifindex)))
455 goto nla_put_failure;
456 if (skb->nf_bridge && skb->nf_bridge->physindev &&
457 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
458 htonl(skb->nf_bridge->physindev->ifindex)))
459 goto nla_put_failure;
460 }
461 #endif
462 }
463
464 if (outdev) {
465 #ifndef CONFIG_BRIDGE_NETFILTER
466 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
467 htonl(outdev->ifindex)))
468 goto nla_put_failure;
469 #else
470 if (pf == PF_BRIDGE) {
471 /* Case 1: outdev is physical output device, we need to
472 * look for bridge group (when called from
473 * netfilter_bridge) */
474 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
475 htonl(outdev->ifindex)) ||
476 /* this is the bridge group "brX" */
477 /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
478 nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
479 htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
480 goto nla_put_failure;
481 } else {
482 /* Case 2: indev is a bridge group, we need to look
483 * for physical device (when called from ipv4) */
484 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
485 htonl(outdev->ifindex)))
486 goto nla_put_failure;
487 if (skb->nf_bridge && skb->nf_bridge->physoutdev &&
488 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
489 htonl(skb->nf_bridge->physoutdev->ifindex)))
490 goto nla_put_failure;
491 }
492 #endif
493 }
494
495 if (skb->mark &&
496 nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
497 goto nla_put_failure;
498
499 if (indev && skb->dev &&
500 skb->mac_header != skb->network_header) {
501 struct nfulnl_msg_packet_hw phw;
502 int len;
503
504 memset(&phw, 0, sizeof(phw));
505 len = dev_parse_header(skb, phw.hw_addr);
506 if (len > 0) {
507 phw.hw_addrlen = htons(len);
508 if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
509 goto nla_put_failure;
510 }
511 }
512
513 if (indev && skb_mac_header_was_set(skb)) {
514 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
515 nla_put_be16(inst->skb, NFULA_HWLEN,
516 htons(skb->dev->hard_header_len)))
517 goto nla_put_failure;
518
519 hwhdrp = skb_mac_header(skb);
520
521 if (skb->dev->type == ARPHRD_SIT)
522 hwhdrp -= ETH_HLEN;
523
524 if (hwhdrp >= skb->head &&
525 nla_put(inst->skb, NFULA_HWHEADER,
526 skb->dev->hard_header_len, hwhdrp))
527 goto nla_put_failure;
528 }
529
530 if (skb->tstamp.tv64) {
531 struct nfulnl_msg_packet_timestamp ts;
532 struct timeval tv = ktime_to_timeval(skb->tstamp);
533 ts.sec = cpu_to_be64(tv.tv_sec);
534 ts.usec = cpu_to_be64(tv.tv_usec);
535
536 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
537 goto nla_put_failure;
538 }
539
540 /* UID */
541 sk = skb->sk;
542 if (sk && sk->sk_state != TCP_TIME_WAIT) {
543 read_lock_bh(&sk->sk_callback_lock);
544 if (sk->sk_socket && sk->sk_socket->file) {
545 struct file *file = sk->sk_socket->file;
546 const struct cred *cred = file->f_cred;
547 struct user_namespace *user_ns = inst->peer_user_ns;
548 __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
549 __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
550 read_unlock_bh(&sk->sk_callback_lock);
551 if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
552 nla_put_be32(inst->skb, NFULA_GID, gid))
553 goto nla_put_failure;
554 } else
555 read_unlock_bh(&sk->sk_callback_lock);
556 }
557
558 /* local sequence number */
559 if ((inst->flags & NFULNL_CFG_F_SEQ) &&
560 nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
561 goto nla_put_failure;
562
563 /* global sequence number */
564 if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
565 nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
566 htonl(atomic_inc_return(&log->global_seq))))
567 goto nla_put_failure;
568
569 if (data_len) {
570 struct nlattr *nla;
571 int size = nla_attr_size(data_len);
572
573 if (skb_tailroom(inst->skb) < nla_total_size(data_len)) {
574 printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
575 return -1;
576 }
577
578 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
579 nla->nla_type = NFULA_PAYLOAD;
580 nla->nla_len = size;
581
582 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
583 BUG();
584 }
585
586 nlh->nlmsg_len = inst->skb->tail - old_tail;
587 return 0;
588
589 nla_put_failure:
590 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
591 return -1;
592 }
593
594 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
595
596 static struct nf_loginfo default_loginfo = {
597 .type = NF_LOG_TYPE_ULOG,
598 .u = {
599 .ulog = {
600 .copy_len = 0xffff,
601 .group = 0,
602 .qthreshold = 1,
603 },
604 },
605 };
606
607 /* log handler for internal netfilter logging api */
608 void
609 nfulnl_log_packet(struct net *net,
610 u_int8_t pf,
611 unsigned int hooknum,
612 const struct sk_buff *skb,
613 const struct net_device *in,
614 const struct net_device *out,
615 const struct nf_loginfo *li_user,
616 const char *prefix)
617 {
618 unsigned int size, data_len;
619 struct nfulnl_instance *inst;
620 const struct nf_loginfo *li;
621 unsigned int qthreshold;
622 unsigned int plen;
623 struct nfnl_log_net *log = nfnl_log_pernet(net);
624
625 if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
626 li = li_user;
627 else
628 li = &default_loginfo;
629
630 inst = instance_lookup_get(log, li->u.ulog.group);
631 if (!inst)
632 return;
633
634 plen = 0;
635 if (prefix)
636 plen = strlen(prefix) + 1;
637
638 /* FIXME: do we want to make the size calculation conditional based on
639 * what is actually present? way more branches and checks, but more
640 * memory efficient... */
641 size = nlmsg_total_size(sizeof(struct nfgenmsg))
642 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
643 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
644 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
645 #ifdef CONFIG_BRIDGE_NETFILTER
646 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
647 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
648 #endif
649 + nla_total_size(sizeof(u_int32_t)) /* mark */
650 + nla_total_size(sizeof(u_int32_t)) /* uid */
651 + nla_total_size(sizeof(u_int32_t)) /* gid */
652 + nla_total_size(plen) /* prefix */
653 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
654 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp));
655
656 if (in && skb_mac_header_was_set(skb)) {
657 size += nla_total_size(skb->dev->hard_header_len)
658 + nla_total_size(sizeof(u_int16_t)) /* hwtype */
659 + nla_total_size(sizeof(u_int16_t)); /* hwlen */
660 }
661
662 spin_lock_bh(&inst->lock);
663
664 if (inst->flags & NFULNL_CFG_F_SEQ)
665 size += nla_total_size(sizeof(u_int32_t));
666 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
667 size += nla_total_size(sizeof(u_int32_t));
668
669 qthreshold = inst->qthreshold;
670 /* per-rule qthreshold overrides per-instance */
671 if (li->u.ulog.qthreshold)
672 if (qthreshold > li->u.ulog.qthreshold)
673 qthreshold = li->u.ulog.qthreshold;
674
675
676 switch (inst->copy_mode) {
677 case NFULNL_COPY_META:
678 case NFULNL_COPY_NONE:
679 data_len = 0;
680 break;
681
682 case NFULNL_COPY_PACKET:
683 if (inst->copy_range == 0
684 || inst->copy_range > skb->len)
685 data_len = skb->len;
686 else
687 data_len = inst->copy_range;
688
689 size += nla_total_size(data_len);
690 break;
691
692 case NFULNL_COPY_DISABLED:
693 default:
694 goto unlock_and_release;
695 }
696
697 if (inst->skb &&
698 size > skb_tailroom(inst->skb) - sizeof(struct nfgenmsg)) {
699 /* either the queue len is too high or we don't have
700 * enough room in the skb left. flush to userspace. */
701 __nfulnl_flush(inst);
702 }
703
704 if (!inst->skb) {
705 inst->skb = nfulnl_alloc_skb(inst->peer_portid, inst->nlbufsiz,
706 size);
707 if (!inst->skb)
708 goto alloc_failure;
709 }
710
711 inst->qlen++;
712
713 __build_packet_message(log, inst, skb, data_len, pf,
714 hooknum, in, out, prefix, plen);
715
716 if (inst->qlen >= qthreshold)
717 __nfulnl_flush(inst);
718 /* timer_pending always called within inst->lock, so there
719 * is no chance of a race here */
720 else if (!timer_pending(&inst->timer)) {
721 instance_get(inst);
722 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
723 add_timer(&inst->timer);
724 }
725
726 unlock_and_release:
727 spin_unlock_bh(&inst->lock);
728 instance_put(inst);
729 return;
730
731 alloc_failure:
732 /* FIXME: statistics */
733 goto unlock_and_release;
734 }
735 EXPORT_SYMBOL_GPL(nfulnl_log_packet);
736
737 static int
738 nfulnl_rcv_nl_event(struct notifier_block *this,
739 unsigned long event, void *ptr)
740 {
741 struct netlink_notify *n = ptr;
742 struct nfnl_log_net *log = nfnl_log_pernet(n->net);
743
744 if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
745 int i;
746
747 /* destroy all instances for this portid */
748 spin_lock_bh(&log->instances_lock);
749 for (i = 0; i < INSTANCE_BUCKETS; i++) {
750 struct hlist_node *t2;
751 struct nfulnl_instance *inst;
752 struct hlist_head *head = &log->instance_table[i];
753
754 hlist_for_each_entry_safe(inst, t2, head, hlist) {
755 if (n->portid == inst->peer_portid)
756 __instance_destroy(inst);
757 }
758 }
759 spin_unlock_bh(&log->instances_lock);
760 }
761 return NOTIFY_DONE;
762 }
763
764 static struct notifier_block nfulnl_rtnl_notifier = {
765 .notifier_call = nfulnl_rcv_nl_event,
766 };
767
768 static int
769 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
770 const struct nlmsghdr *nlh,
771 const struct nlattr * const nfqa[])
772 {
773 return -ENOTSUPP;
774 }
775
776 static struct nf_logger nfulnl_logger __read_mostly = {
777 .name = "nfnetlink_log",
778 .logfn = &nfulnl_log_packet,
779 .me = THIS_MODULE,
780 };
781
782 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
783 [NFULA_CFG_CMD] = { .len = sizeof(struct nfulnl_msg_config_cmd) },
784 [NFULA_CFG_MODE] = { .len = sizeof(struct nfulnl_msg_config_mode) },
785 [NFULA_CFG_TIMEOUT] = { .type = NLA_U32 },
786 [NFULA_CFG_QTHRESH] = { .type = NLA_U32 },
787 [NFULA_CFG_NLBUFSIZ] = { .type = NLA_U32 },
788 [NFULA_CFG_FLAGS] = { .type = NLA_U16 },
789 };
790
791 static int
792 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
793 const struct nlmsghdr *nlh,
794 const struct nlattr * const nfula[])
795 {
796 struct nfgenmsg *nfmsg = nlmsg_data(nlh);
797 u_int16_t group_num = ntohs(nfmsg->res_id);
798 struct nfulnl_instance *inst;
799 struct nfulnl_msg_config_cmd *cmd = NULL;
800 struct net *net = sock_net(ctnl);
801 struct nfnl_log_net *log = nfnl_log_pernet(net);
802 int ret = 0;
803
804 if (nfula[NFULA_CFG_CMD]) {
805 u_int8_t pf = nfmsg->nfgen_family;
806 cmd = nla_data(nfula[NFULA_CFG_CMD]);
807
808 /* Commands without queue context */
809 switch (cmd->command) {
810 case NFULNL_CFG_CMD_PF_BIND:
811 return nf_log_bind_pf(net, pf, &nfulnl_logger);
812 case NFULNL_CFG_CMD_PF_UNBIND:
813 nf_log_unbind_pf(net, pf);
814 return 0;
815 }
816 }
817
818 inst = instance_lookup_get(log, group_num);
819 if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
820 ret = -EPERM;
821 goto out_put;
822 }
823
824 if (cmd != NULL) {
825 switch (cmd->command) {
826 case NFULNL_CFG_CMD_BIND:
827 if (inst) {
828 ret = -EBUSY;
829 goto out_put;
830 }
831
832 inst = instance_create(net, group_num,
833 NETLINK_CB(skb).portid,
834 sk_user_ns(NETLINK_CB(skb).sk));
835 if (IS_ERR(inst)) {
836 ret = PTR_ERR(inst);
837 goto out;
838 }
839 break;
840 case NFULNL_CFG_CMD_UNBIND:
841 if (!inst) {
842 ret = -ENODEV;
843 goto out;
844 }
845
846 instance_destroy(log, inst);
847 goto out_put;
848 default:
849 ret = -ENOTSUPP;
850 break;
851 }
852 }
853
854 if (nfula[NFULA_CFG_MODE]) {
855 struct nfulnl_msg_config_mode *params;
856 params = nla_data(nfula[NFULA_CFG_MODE]);
857
858 if (!inst) {
859 ret = -ENODEV;
860 goto out;
861 }
862 nfulnl_set_mode(inst, params->copy_mode,
863 ntohl(params->copy_range));
864 }
865
866 if (nfula[NFULA_CFG_TIMEOUT]) {
867 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
868
869 if (!inst) {
870 ret = -ENODEV;
871 goto out;
872 }
873 nfulnl_set_timeout(inst, ntohl(timeout));
874 }
875
876 if (nfula[NFULA_CFG_NLBUFSIZ]) {
877 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
878
879 if (!inst) {
880 ret = -ENODEV;
881 goto out;
882 }
883 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
884 }
885
886 if (nfula[NFULA_CFG_QTHRESH]) {
887 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
888
889 if (!inst) {
890 ret = -ENODEV;
891 goto out;
892 }
893 nfulnl_set_qthresh(inst, ntohl(qthresh));
894 }
895
896 if (nfula[NFULA_CFG_FLAGS]) {
897 __be16 flags = nla_get_be16(nfula[NFULA_CFG_FLAGS]);
898
899 if (!inst) {
900 ret = -ENODEV;
901 goto out;
902 }
903 nfulnl_set_flags(inst, ntohs(flags));
904 }
905
906 out_put:
907 instance_put(inst);
908 out:
909 return ret;
910 }
911
912 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
913 [NFULNL_MSG_PACKET] = { .call = nfulnl_recv_unsupp,
914 .attr_count = NFULA_MAX, },
915 [NFULNL_MSG_CONFIG] = { .call = nfulnl_recv_config,
916 .attr_count = NFULA_CFG_MAX,
917 .policy = nfula_cfg_policy },
918 };
919
920 static const struct nfnetlink_subsystem nfulnl_subsys = {
921 .name = "log",
922 .subsys_id = NFNL_SUBSYS_ULOG,
923 .cb_count = NFULNL_MSG_MAX,
924 .cb = nfulnl_cb,
925 };
926
927 #ifdef CONFIG_PROC_FS
928 struct iter_state {
929 struct seq_net_private p;
930 unsigned int bucket;
931 };
932
933 static struct hlist_node *get_first(struct net *net, struct iter_state *st)
934 {
935 struct nfnl_log_net *log;
936 if (!st)
937 return NULL;
938
939 log = nfnl_log_pernet(net);
940
941 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
942 struct hlist_head *head = &log->instance_table[st->bucket];
943
944 if (!hlist_empty(head))
945 return rcu_dereference_bh(hlist_first_rcu(head));
946 }
947 return NULL;
948 }
949
950 static struct hlist_node *get_next(struct net *net, struct iter_state *st,
951 struct hlist_node *h)
952 {
953 h = rcu_dereference_bh(hlist_next_rcu(h));
954 while (!h) {
955 struct nfnl_log_net *log;
956 struct hlist_head *head;
957
958 if (++st->bucket >= INSTANCE_BUCKETS)
959 return NULL;
960
961 log = nfnl_log_pernet(net);
962 head = &log->instance_table[st->bucket];
963 h = rcu_dereference_bh(hlist_first_rcu(head));
964 }
965 return h;
966 }
967
968 static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
969 loff_t pos)
970 {
971 struct hlist_node *head;
972 head = get_first(net, st);
973
974 if (head)
975 while (pos && (head = get_next(net, st, head)))
976 pos--;
977 return pos ? NULL : head;
978 }
979
980 static void *seq_start(struct seq_file *s, loff_t *pos)
981 __acquires(rcu_bh)
982 {
983 rcu_read_lock_bh();
984 return get_idx(seq_file_net(s), s->private, *pos);
985 }
986
987 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
988 {
989 (*pos)++;
990 return get_next(seq_file_net(s), s->private, v);
991 }
992
993 static void seq_stop(struct seq_file *s, void *v)
994 __releases(rcu_bh)
995 {
996 rcu_read_unlock_bh();
997 }
998
999 static int seq_show(struct seq_file *s, void *v)
1000 {
1001 const struct nfulnl_instance *inst = v;
1002
1003 return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
1004 inst->group_num,
1005 inst->peer_portid, inst->qlen,
1006 inst->copy_mode, inst->copy_range,
1007 inst->flushtimeout, atomic_read(&inst->use));
1008 }
1009
1010 static const struct seq_operations nful_seq_ops = {
1011 .start = seq_start,
1012 .next = seq_next,
1013 .stop = seq_stop,
1014 .show = seq_show,
1015 };
1016
1017 static int nful_open(struct inode *inode, struct file *file)
1018 {
1019 return seq_open_net(inode, file, &nful_seq_ops,
1020 sizeof(struct iter_state));
1021 }
1022
1023 static const struct file_operations nful_file_ops = {
1024 .owner = THIS_MODULE,
1025 .open = nful_open,
1026 .read = seq_read,
1027 .llseek = seq_lseek,
1028 .release = seq_release_net,
1029 };
1030
1031 #endif /* PROC_FS */
1032
1033 static int __net_init nfnl_log_net_init(struct net *net)
1034 {
1035 unsigned int i;
1036 struct nfnl_log_net *log = nfnl_log_pernet(net);
1037
1038 for (i = 0; i < INSTANCE_BUCKETS; i++)
1039 INIT_HLIST_HEAD(&log->instance_table[i]);
1040 spin_lock_init(&log->instances_lock);
1041
1042 #ifdef CONFIG_PROC_FS
1043 if (!proc_create("nfnetlink_log", 0440,
1044 net->nf.proc_netfilter, &nful_file_ops))
1045 return -ENOMEM;
1046 #endif
1047 return 0;
1048 }
1049
1050 static void __net_exit nfnl_log_net_exit(struct net *net)
1051 {
1052 #ifdef CONFIG_PROC_FS
1053 remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1054 #endif
1055 }
1056
1057 static struct pernet_operations nfnl_log_net_ops = {
1058 .init = nfnl_log_net_init,
1059 .exit = nfnl_log_net_exit,
1060 .id = &nfnl_log_net_id,
1061 .size = sizeof(struct nfnl_log_net),
1062 };
1063
1064 static int __init nfnetlink_log_init(void)
1065 {
1066 int status = -ENOMEM;
1067
1068 /* it's not really all that important to have a random value, so
1069 * we can do this from the init function, even if there hasn't
1070 * been that much entropy yet */
1071 get_random_bytes(&hash_init, sizeof(hash_init));
1072
1073 netlink_register_notifier(&nfulnl_rtnl_notifier);
1074 status = nfnetlink_subsys_register(&nfulnl_subsys);
1075 if (status < 0) {
1076 pr_err("log: failed to create netlink socket\n");
1077 goto cleanup_netlink_notifier;
1078 }
1079
1080 status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1081 if (status < 0) {
1082 pr_err("log: failed to register logger\n");
1083 goto cleanup_subsys;
1084 }
1085
1086 status = register_pernet_subsys(&nfnl_log_net_ops);
1087 if (status < 0) {
1088 pr_err("log: failed to register pernet ops\n");
1089 goto cleanup_logger;
1090 }
1091 return status;
1092
1093 cleanup_logger:
1094 nf_log_unregister(&nfulnl_logger);
1095 cleanup_subsys:
1096 nfnetlink_subsys_unregister(&nfulnl_subsys);
1097 cleanup_netlink_notifier:
1098 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1099 return status;
1100 }
1101
1102 static void __exit nfnetlink_log_fini(void)
1103 {
1104 unregister_pernet_subsys(&nfnl_log_net_ops);
1105 nf_log_unregister(&nfulnl_logger);
1106 nfnetlink_subsys_unregister(&nfulnl_subsys);
1107 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1108 }
1109
1110 MODULE_DESCRIPTION("netfilter userspace logging");
1111 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1112 MODULE_LICENSE("GPL");
1113 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1114
1115 module_init(nfnetlink_log_init);
1116 module_exit(nfnetlink_log_fini);
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