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[mirror_ubuntu-zesty-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
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18 #include <linux/module.h>
19 #include <linux/skbuff.h>
20 #include <linux/if_arp.h>
21 #include <linux/init.h>
22 #include <linux/ip.h>
23 #include <linux/ipv6.h>
24 #include <linux/netdevice.h>
25 #include <linux/netfilter.h>
26 #include <linux/netfilter_bridge.h>
27 #include <net/netlink.h>
28 #include <linux/netfilter/nfnetlink.h>
29 #include <linux/netfilter/nfnetlink_log.h>
30 #include <linux/netfilter/nf_conntrack_common.h>
31 #include <linux/spinlock.h>
32 #include <linux/sysctl.h>
33 #include <linux/proc_fs.h>
34 #include <linux/security.h>
35 #include <linux/list.h>
36 #include <linux/slab.h>
37 #include <net/sock.h>
38 #include <net/netfilter/nf_log.h>
39 #include <net/netns/generic.h>
40 #include <net/netfilter/nfnetlink_log.h>
41
42 #include <linux/atomic.h>
43
44 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
45 #include "../bridge/br_private.h"
46 #endif
47
48 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
49 #define NFULNL_TIMEOUT_DEFAULT 100 /* every second */
50 #define NFULNL_QTHRESH_DEFAULT 100 /* 100 packets */
51 /* max packet size is limited by 16-bit struct nfattr nfa_len field */
52 #define NFULNL_COPY_RANGE_MAX (0xFFFF - NLA_HDRLEN)
53
54 #define PRINTR(x, args...) do { if (net_ratelimit()) \
55 printk(x, ## args); } while (0);
56
57 struct nfulnl_instance {
58 struct hlist_node hlist; /* global list of instances */
59 spinlock_t lock;
60 atomic_t use; /* use count */
61
62 unsigned int qlen; /* number of nlmsgs in skb */
63 struct sk_buff *skb; /* pre-allocatd skb */
64 struct timer_list timer;
65 struct net *net;
66 struct user_namespace *peer_user_ns; /* User namespace of the peer process */
67 u32 peer_portid; /* PORTID of the peer process */
68
69 /* configurable parameters */
70 unsigned int flushtimeout; /* timeout until queue flush */
71 unsigned int nlbufsiz; /* netlink buffer allocation size */
72 unsigned int qthreshold; /* threshold of the queue */
73 u_int32_t copy_range;
74 u_int32_t seq; /* instance-local sequential counter */
75 u_int16_t group_num; /* number of this queue */
76 u_int16_t flags;
77 u_int8_t copy_mode;
78 struct rcu_head rcu;
79 };
80
81 #define INSTANCE_BUCKETS 16
82
83 static int nfnl_log_net_id __read_mostly;
84
85 struct nfnl_log_net {
86 spinlock_t instances_lock;
87 struct hlist_head instance_table[INSTANCE_BUCKETS];
88 atomic_t global_seq;
89 };
90
91 static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
92 {
93 return net_generic(net, nfnl_log_net_id);
94 }
95
96 static inline u_int8_t instance_hashfn(u_int16_t group_num)
97 {
98 return ((group_num & 0xff) % INSTANCE_BUCKETS);
99 }
100
101 static struct nfulnl_instance *
102 __instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
103 {
104 struct hlist_head *head;
105 struct nfulnl_instance *inst;
106
107 head = &log->instance_table[instance_hashfn(group_num)];
108 hlist_for_each_entry_rcu(inst, head, hlist) {
109 if (inst->group_num == group_num)
110 return inst;
111 }
112 return NULL;
113 }
114
115 static inline void
116 instance_get(struct nfulnl_instance *inst)
117 {
118 atomic_inc(&inst->use);
119 }
120
121 static struct nfulnl_instance *
122 instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
123 {
124 struct nfulnl_instance *inst;
125
126 rcu_read_lock_bh();
127 inst = __instance_lookup(log, group_num);
128 if (inst && !atomic_inc_not_zero(&inst->use))
129 inst = NULL;
130 rcu_read_unlock_bh();
131
132 return inst;
133 }
134
135 static void nfulnl_instance_free_rcu(struct rcu_head *head)
136 {
137 struct nfulnl_instance *inst =
138 container_of(head, struct nfulnl_instance, rcu);
139
140 put_net(inst->net);
141 kfree(inst);
142 module_put(THIS_MODULE);
143 }
144
145 static void
146 instance_put(struct nfulnl_instance *inst)
147 {
148 if (inst && atomic_dec_and_test(&inst->use))
149 call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
150 }
151
152 static void nfulnl_timer(unsigned long data);
153
154 static struct nfulnl_instance *
155 instance_create(struct net *net, u_int16_t group_num,
156 u32 portid, struct user_namespace *user_ns)
157 {
158 struct nfulnl_instance *inst;
159 struct nfnl_log_net *log = nfnl_log_pernet(net);
160 int err;
161
162 spin_lock_bh(&log->instances_lock);
163 if (__instance_lookup(log, group_num)) {
164 err = -EEXIST;
165 goto out_unlock;
166 }
167
168 inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
169 if (!inst) {
170 err = -ENOMEM;
171 goto out_unlock;
172 }
173
174 if (!try_module_get(THIS_MODULE)) {
175 kfree(inst);
176 err = -EAGAIN;
177 goto out_unlock;
178 }
179
180 INIT_HLIST_NODE(&inst->hlist);
181 spin_lock_init(&inst->lock);
182 /* needs to be two, since we _put() after creation */
183 atomic_set(&inst->use, 2);
184
185 setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
186
187 inst->net = get_net(net);
188 inst->peer_user_ns = user_ns;
189 inst->peer_portid = portid;
190 inst->group_num = group_num;
191
192 inst->qthreshold = NFULNL_QTHRESH_DEFAULT;
193 inst->flushtimeout = NFULNL_TIMEOUT_DEFAULT;
194 inst->nlbufsiz = NFULNL_NLBUFSIZ_DEFAULT;
195 inst->copy_mode = NFULNL_COPY_PACKET;
196 inst->copy_range = NFULNL_COPY_RANGE_MAX;
197
198 hlist_add_head_rcu(&inst->hlist,
199 &log->instance_table[instance_hashfn(group_num)]);
200
201
202 spin_unlock_bh(&log->instances_lock);
203
204 return inst;
205
206 out_unlock:
207 spin_unlock_bh(&log->instances_lock);
208 return ERR_PTR(err);
209 }
210
211 static void __nfulnl_flush(struct nfulnl_instance *inst);
212
213 /* called with BH disabled */
214 static void
215 __instance_destroy(struct nfulnl_instance *inst)
216 {
217 /* first pull it out of the global list */
218 hlist_del_rcu(&inst->hlist);
219
220 /* then flush all pending packets from skb */
221
222 spin_lock(&inst->lock);
223
224 /* lockless readers wont be able to use us */
225 inst->copy_mode = NFULNL_COPY_DISABLED;
226
227 if (inst->skb)
228 __nfulnl_flush(inst);
229 spin_unlock(&inst->lock);
230
231 /* and finally put the refcount */
232 instance_put(inst);
233 }
234
235 static inline void
236 instance_destroy(struct nfnl_log_net *log,
237 struct nfulnl_instance *inst)
238 {
239 spin_lock_bh(&log->instances_lock);
240 __instance_destroy(inst);
241 spin_unlock_bh(&log->instances_lock);
242 }
243
244 static int
245 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
246 unsigned int range)
247 {
248 int status = 0;
249
250 spin_lock_bh(&inst->lock);
251
252 switch (mode) {
253 case NFULNL_COPY_NONE:
254 case NFULNL_COPY_META:
255 inst->copy_mode = mode;
256 inst->copy_range = 0;
257 break;
258
259 case NFULNL_COPY_PACKET:
260 inst->copy_mode = mode;
261 if (range == 0)
262 range = NFULNL_COPY_RANGE_MAX;
263 inst->copy_range = min_t(unsigned int,
264 range, NFULNL_COPY_RANGE_MAX);
265 break;
266
267 default:
268 status = -EINVAL;
269 break;
270 }
271
272 spin_unlock_bh(&inst->lock);
273
274 return status;
275 }
276
277 static int
278 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
279 {
280 int status;
281
282 spin_lock_bh(&inst->lock);
283 if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
284 status = -ERANGE;
285 else if (nlbufsiz > 131072)
286 status = -ERANGE;
287 else {
288 inst->nlbufsiz = nlbufsiz;
289 status = 0;
290 }
291 spin_unlock_bh(&inst->lock);
292
293 return status;
294 }
295
296 static void
297 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
298 {
299 spin_lock_bh(&inst->lock);
300 inst->flushtimeout = timeout;
301 spin_unlock_bh(&inst->lock);
302 }
303
304 static void
305 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
306 {
307 spin_lock_bh(&inst->lock);
308 inst->qthreshold = qthresh;
309 spin_unlock_bh(&inst->lock);
310 }
311
312 static int
313 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
314 {
315 spin_lock_bh(&inst->lock);
316 inst->flags = flags;
317 spin_unlock_bh(&inst->lock);
318
319 return 0;
320 }
321
322 static struct sk_buff *
323 nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
324 unsigned int pkt_size)
325 {
326 struct sk_buff *skb;
327 unsigned int n;
328
329 /* alloc skb which should be big enough for a whole multipart
330 * message. WARNING: has to be <= 128k due to slab restrictions */
331
332 n = max(inst_size, pkt_size);
333 skb = alloc_skb(n, GFP_ATOMIC);
334 if (!skb) {
335 if (n > pkt_size) {
336 /* try to allocate only as much as we need for current
337 * packet */
338
339 skb = alloc_skb(pkt_size, GFP_ATOMIC);
340 }
341 }
342
343 return skb;
344 }
345
346 static void
347 __nfulnl_send(struct nfulnl_instance *inst)
348 {
349 if (inst->qlen > 1) {
350 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
351 NLMSG_DONE,
352 sizeof(struct nfgenmsg),
353 0);
354 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
355 inst->skb->len, skb_tailroom(inst->skb))) {
356 kfree_skb(inst->skb);
357 goto out;
358 }
359 }
360 nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
361 MSG_DONTWAIT);
362 out:
363 inst->qlen = 0;
364 inst->skb = NULL;
365 }
366
367 static void
368 __nfulnl_flush(struct nfulnl_instance *inst)
369 {
370 /* timer holds a reference */
371 if (del_timer(&inst->timer))
372 instance_put(inst);
373 if (inst->skb)
374 __nfulnl_send(inst);
375 }
376
377 static void
378 nfulnl_timer(unsigned long data)
379 {
380 struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
381
382 spin_lock_bh(&inst->lock);
383 if (inst->skb)
384 __nfulnl_send(inst);
385 spin_unlock_bh(&inst->lock);
386 instance_put(inst);
387 }
388
389 /* This is an inline function, we don't really care about a long
390 * list of arguments */
391 static inline int
392 __build_packet_message(struct nfnl_log_net *log,
393 struct nfulnl_instance *inst,
394 const struct sk_buff *skb,
395 unsigned int data_len,
396 u_int8_t pf,
397 unsigned int hooknum,
398 const struct net_device *indev,
399 const struct net_device *outdev,
400 const char *prefix, unsigned int plen,
401 const struct nfnl_ct_hook *nfnl_ct,
402 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
403 {
404 struct nfulnl_msg_packet_hdr pmsg;
405 struct nlmsghdr *nlh;
406 struct nfgenmsg *nfmsg;
407 sk_buff_data_t old_tail = inst->skb->tail;
408 struct sock *sk;
409 const unsigned char *hwhdrp;
410
411 nlh = nlmsg_put(inst->skb, 0, 0,
412 NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
413 sizeof(struct nfgenmsg), 0);
414 if (!nlh)
415 return -1;
416 nfmsg = nlmsg_data(nlh);
417 nfmsg->nfgen_family = pf;
418 nfmsg->version = NFNETLINK_V0;
419 nfmsg->res_id = htons(inst->group_num);
420
421 memset(&pmsg, 0, sizeof(pmsg));
422 pmsg.hw_protocol = skb->protocol;
423 pmsg.hook = hooknum;
424
425 if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
426 goto nla_put_failure;
427
428 if (prefix &&
429 nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
430 goto nla_put_failure;
431
432 if (indev) {
433 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
434 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
435 htonl(indev->ifindex)))
436 goto nla_put_failure;
437 #else
438 if (pf == PF_BRIDGE) {
439 /* Case 1: outdev is physical input device, we need to
440 * look for bridge group (when called from
441 * netfilter_bridge) */
442 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
443 htonl(indev->ifindex)) ||
444 /* this is the bridge group "brX" */
445 /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
446 nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
447 htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
448 goto nla_put_failure;
449 } else {
450 struct net_device *physindev;
451
452 /* Case 2: indev is bridge group, we need to look for
453 * physical device (when called from ipv4) */
454 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
455 htonl(indev->ifindex)))
456 goto nla_put_failure;
457
458 physindev = nf_bridge_get_physindev(skb);
459 if (physindev &&
460 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
461 htonl(physindev->ifindex)))
462 goto nla_put_failure;
463 }
464 #endif
465 }
466
467 if (outdev) {
468 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
469 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
470 htonl(outdev->ifindex)))
471 goto nla_put_failure;
472 #else
473 if (pf == PF_BRIDGE) {
474 /* Case 1: outdev is physical output device, we need to
475 * look for bridge group (when called from
476 * netfilter_bridge) */
477 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
478 htonl(outdev->ifindex)) ||
479 /* this is the bridge group "brX" */
480 /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
481 nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
482 htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
483 goto nla_put_failure;
484 } else {
485 struct net_device *physoutdev;
486
487 /* Case 2: indev is a bridge group, we need to look
488 * for physical device (when called from ipv4) */
489 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
490 htonl(outdev->ifindex)))
491 goto nla_put_failure;
492
493 physoutdev = nf_bridge_get_physoutdev(skb);
494 if (physoutdev &&
495 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
496 htonl(physoutdev->ifindex)))
497 goto nla_put_failure;
498 }
499 #endif
500 }
501
502 if (skb->mark &&
503 nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
504 goto nla_put_failure;
505
506 if (indev && skb->dev &&
507 skb->mac_header != skb->network_header) {
508 struct nfulnl_msg_packet_hw phw;
509 int len;
510
511 memset(&phw, 0, sizeof(phw));
512 len = dev_parse_header(skb, phw.hw_addr);
513 if (len > 0) {
514 phw.hw_addrlen = htons(len);
515 if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
516 goto nla_put_failure;
517 }
518 }
519
520 if (indev && skb_mac_header_was_set(skb)) {
521 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
522 nla_put_be16(inst->skb, NFULA_HWLEN,
523 htons(skb->dev->hard_header_len)))
524 goto nla_put_failure;
525
526 hwhdrp = skb_mac_header(skb);
527
528 if (skb->dev->type == ARPHRD_SIT)
529 hwhdrp -= ETH_HLEN;
530
531 if (hwhdrp >= skb->head &&
532 nla_put(inst->skb, NFULA_HWHEADER,
533 skb->dev->hard_header_len, hwhdrp))
534 goto nla_put_failure;
535 }
536
537 if (skb->tstamp.tv64) {
538 struct nfulnl_msg_packet_timestamp ts;
539 struct timespec64 kts = ktime_to_timespec64(skb->tstamp);
540 ts.sec = cpu_to_be64(kts.tv_sec);
541 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
542
543 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
544 goto nla_put_failure;
545 }
546
547 /* UID */
548 sk = skb->sk;
549 if (sk && sk_fullsock(sk)) {
550 read_lock_bh(&sk->sk_callback_lock);
551 if (sk->sk_socket && sk->sk_socket->file) {
552 struct file *file = sk->sk_socket->file;
553 const struct cred *cred = file->f_cred;
554 struct user_namespace *user_ns = inst->peer_user_ns;
555 __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
556 __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
557 read_unlock_bh(&sk->sk_callback_lock);
558 if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
559 nla_put_be32(inst->skb, NFULA_GID, gid))
560 goto nla_put_failure;
561 } else
562 read_unlock_bh(&sk->sk_callback_lock);
563 }
564
565 /* local sequence number */
566 if ((inst->flags & NFULNL_CFG_F_SEQ) &&
567 nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
568 goto nla_put_failure;
569
570 /* global sequence number */
571 if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
572 nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
573 htonl(atomic_inc_return(&log->global_seq))))
574 goto nla_put_failure;
575
576 if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
577 NFULA_CT, NFULA_CT_INFO) < 0)
578 goto nla_put_failure;
579
580 if (data_len) {
581 struct nlattr *nla;
582 int size = nla_attr_size(data_len);
583
584 if (skb_tailroom(inst->skb) < nla_total_size(data_len))
585 goto nla_put_failure;
586
587 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
588 nla->nla_type = NFULA_PAYLOAD;
589 nla->nla_len = size;
590
591 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
592 BUG();
593 }
594
595 nlh->nlmsg_len = inst->skb->tail - old_tail;
596 return 0;
597
598 nla_put_failure:
599 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
600 return -1;
601 }
602
603 static struct nf_loginfo default_loginfo = {
604 .type = NF_LOG_TYPE_ULOG,
605 .u = {
606 .ulog = {
607 .copy_len = 0xffff,
608 .group = 0,
609 .qthreshold = 1,
610 },
611 },
612 };
613
614 /* log handler for internal netfilter logging api */
615 void
616 nfulnl_log_packet(struct net *net,
617 u_int8_t pf,
618 unsigned int hooknum,
619 const struct sk_buff *skb,
620 const struct net_device *in,
621 const struct net_device *out,
622 const struct nf_loginfo *li_user,
623 const char *prefix)
624 {
625 size_t size;
626 unsigned int data_len;
627 struct nfulnl_instance *inst;
628 const struct nf_loginfo *li;
629 unsigned int qthreshold;
630 unsigned int plen;
631 struct nfnl_log_net *log = nfnl_log_pernet(net);
632 const struct nfnl_ct_hook *nfnl_ct = NULL;
633 struct nf_conn *ct = NULL;
634 enum ip_conntrack_info uninitialized_var(ctinfo);
635
636 if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
637 li = li_user;
638 else
639 li = &default_loginfo;
640
641 inst = instance_lookup_get(log, li->u.ulog.group);
642 if (!inst)
643 return;
644
645 plen = 0;
646 if (prefix)
647 plen = strlen(prefix) + 1;
648
649 /* FIXME: do we want to make the size calculation conditional based on
650 * what is actually present? way more branches and checks, but more
651 * memory efficient... */
652 size = nlmsg_total_size(sizeof(struct nfgenmsg))
653 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
654 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
655 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
656 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
657 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
658 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
659 #endif
660 + nla_total_size(sizeof(u_int32_t)) /* mark */
661 + nla_total_size(sizeof(u_int32_t)) /* uid */
662 + nla_total_size(sizeof(u_int32_t)) /* gid */
663 + nla_total_size(plen) /* prefix */
664 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
665 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
666 + nla_total_size(sizeof(struct nfgenmsg)); /* NLMSG_DONE */
667
668 if (in && skb_mac_header_was_set(skb)) {
669 size += nla_total_size(skb->dev->hard_header_len)
670 + nla_total_size(sizeof(u_int16_t)) /* hwtype */
671 + nla_total_size(sizeof(u_int16_t)); /* hwlen */
672 }
673
674 spin_lock_bh(&inst->lock);
675
676 if (inst->flags & NFULNL_CFG_F_SEQ)
677 size += nla_total_size(sizeof(u_int32_t));
678 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
679 size += nla_total_size(sizeof(u_int32_t));
680 if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
681 nfnl_ct = rcu_dereference(nfnl_ct_hook);
682 if (nfnl_ct != NULL) {
683 ct = nfnl_ct->get_ct(skb, &ctinfo);
684 if (ct != NULL)
685 size += nfnl_ct->build_size(ct);
686 }
687 }
688
689 qthreshold = inst->qthreshold;
690 /* per-rule qthreshold overrides per-instance */
691 if (li->u.ulog.qthreshold)
692 if (qthreshold > li->u.ulog.qthreshold)
693 qthreshold = li->u.ulog.qthreshold;
694
695
696 switch (inst->copy_mode) {
697 case NFULNL_COPY_META:
698 case NFULNL_COPY_NONE:
699 data_len = 0;
700 break;
701
702 case NFULNL_COPY_PACKET:
703 data_len = inst->copy_range;
704 if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) &&
705 (li->u.ulog.copy_len < data_len))
706 data_len = li->u.ulog.copy_len;
707
708 if (data_len > skb->len)
709 data_len = skb->len;
710
711 size += nla_total_size(data_len);
712 break;
713
714 case NFULNL_COPY_DISABLED:
715 default:
716 goto unlock_and_release;
717 }
718
719 if (inst->skb && size > skb_tailroom(inst->skb)) {
720 /* either the queue len is too high or we don't have
721 * enough room in the skb left. flush to userspace. */
722 __nfulnl_flush(inst);
723 }
724
725 if (!inst->skb) {
726 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
727 inst->nlbufsiz, size);
728 if (!inst->skb)
729 goto alloc_failure;
730 }
731
732 inst->qlen++;
733
734 __build_packet_message(log, inst, skb, data_len, pf,
735 hooknum, in, out, prefix, plen,
736 nfnl_ct, ct, ctinfo);
737
738 if (inst->qlen >= qthreshold)
739 __nfulnl_flush(inst);
740 /* timer_pending always called within inst->lock, so there
741 * is no chance of a race here */
742 else if (!timer_pending(&inst->timer)) {
743 instance_get(inst);
744 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
745 add_timer(&inst->timer);
746 }
747
748 unlock_and_release:
749 spin_unlock_bh(&inst->lock);
750 instance_put(inst);
751 return;
752
753 alloc_failure:
754 /* FIXME: statistics */
755 goto unlock_and_release;
756 }
757 EXPORT_SYMBOL_GPL(nfulnl_log_packet);
758
759 static int
760 nfulnl_rcv_nl_event(struct notifier_block *this,
761 unsigned long event, void *ptr)
762 {
763 struct netlink_notify *n = ptr;
764 struct nfnl_log_net *log = nfnl_log_pernet(n->net);
765
766 if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
767 int i;
768
769 /* destroy all instances for this portid */
770 spin_lock_bh(&log->instances_lock);
771 for (i = 0; i < INSTANCE_BUCKETS; i++) {
772 struct hlist_node *t2;
773 struct nfulnl_instance *inst;
774 struct hlist_head *head = &log->instance_table[i];
775
776 hlist_for_each_entry_safe(inst, t2, head, hlist) {
777 if (n->portid == inst->peer_portid)
778 __instance_destroy(inst);
779 }
780 }
781 spin_unlock_bh(&log->instances_lock);
782 }
783 return NOTIFY_DONE;
784 }
785
786 static struct notifier_block nfulnl_rtnl_notifier = {
787 .notifier_call = nfulnl_rcv_nl_event,
788 };
789
790 static int nfulnl_recv_unsupp(struct net *net, struct sock *ctnl,
791 struct sk_buff *skb, const struct nlmsghdr *nlh,
792 const struct nlattr * const nfqa[])
793 {
794 return -ENOTSUPP;
795 }
796
797 static struct nf_logger nfulnl_logger __read_mostly = {
798 .name = "nfnetlink_log",
799 .type = NF_LOG_TYPE_ULOG,
800 .logfn = &nfulnl_log_packet,
801 .me = THIS_MODULE,
802 };
803
804 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
805 [NFULA_CFG_CMD] = { .len = sizeof(struct nfulnl_msg_config_cmd) },
806 [NFULA_CFG_MODE] = { .len = sizeof(struct nfulnl_msg_config_mode) },
807 [NFULA_CFG_TIMEOUT] = { .type = NLA_U32 },
808 [NFULA_CFG_QTHRESH] = { .type = NLA_U32 },
809 [NFULA_CFG_NLBUFSIZ] = { .type = NLA_U32 },
810 [NFULA_CFG_FLAGS] = { .type = NLA_U16 },
811 };
812
813 static int nfulnl_recv_config(struct net *net, struct sock *ctnl,
814 struct sk_buff *skb, const struct nlmsghdr *nlh,
815 const struct nlattr * const nfula[])
816 {
817 struct nfgenmsg *nfmsg = nlmsg_data(nlh);
818 u_int16_t group_num = ntohs(nfmsg->res_id);
819 struct nfulnl_instance *inst;
820 struct nfulnl_msg_config_cmd *cmd = NULL;
821 struct nfnl_log_net *log = nfnl_log_pernet(net);
822 int ret = 0;
823 u16 flags = 0;
824
825 if (nfula[NFULA_CFG_CMD]) {
826 u_int8_t pf = nfmsg->nfgen_family;
827 cmd = nla_data(nfula[NFULA_CFG_CMD]);
828
829 /* Commands without queue context */
830 switch (cmd->command) {
831 case NFULNL_CFG_CMD_PF_BIND:
832 return nf_log_bind_pf(net, pf, &nfulnl_logger);
833 case NFULNL_CFG_CMD_PF_UNBIND:
834 nf_log_unbind_pf(net, pf);
835 return 0;
836 }
837 }
838
839 inst = instance_lookup_get(log, group_num);
840 if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
841 ret = -EPERM;
842 goto out_put;
843 }
844
845 /* Check if we support these flags in first place, dependencies should
846 * be there too not to break atomicity.
847 */
848 if (nfula[NFULA_CFG_FLAGS]) {
849 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
850
851 if ((flags & NFULNL_CFG_F_CONNTRACK) &&
852 !rcu_access_pointer(nfnl_ct_hook)) {
853 #ifdef CONFIG_MODULES
854 nfnl_unlock(NFNL_SUBSYS_ULOG);
855 request_module("ip_conntrack_netlink");
856 nfnl_lock(NFNL_SUBSYS_ULOG);
857 if (rcu_access_pointer(nfnl_ct_hook)) {
858 ret = -EAGAIN;
859 goto out_put;
860 }
861 #endif
862 ret = -EOPNOTSUPP;
863 goto out_put;
864 }
865 }
866
867 if (cmd != NULL) {
868 switch (cmd->command) {
869 case NFULNL_CFG_CMD_BIND:
870 if (inst) {
871 ret = -EBUSY;
872 goto out_put;
873 }
874
875 inst = instance_create(net, group_num,
876 NETLINK_CB(skb).portid,
877 sk_user_ns(NETLINK_CB(skb).sk));
878 if (IS_ERR(inst)) {
879 ret = PTR_ERR(inst);
880 goto out;
881 }
882 break;
883 case NFULNL_CFG_CMD_UNBIND:
884 if (!inst) {
885 ret = -ENODEV;
886 goto out;
887 }
888
889 instance_destroy(log, inst);
890 goto out_put;
891 default:
892 ret = -ENOTSUPP;
893 goto out_put;
894 }
895 } else if (!inst) {
896 ret = -ENODEV;
897 goto out;
898 }
899
900 if (nfula[NFULA_CFG_MODE]) {
901 struct nfulnl_msg_config_mode *params =
902 nla_data(nfula[NFULA_CFG_MODE]);
903
904 nfulnl_set_mode(inst, params->copy_mode,
905 ntohl(params->copy_range));
906 }
907
908 if (nfula[NFULA_CFG_TIMEOUT]) {
909 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
910
911 nfulnl_set_timeout(inst, ntohl(timeout));
912 }
913
914 if (nfula[NFULA_CFG_NLBUFSIZ]) {
915 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
916
917 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
918 }
919
920 if (nfula[NFULA_CFG_QTHRESH]) {
921 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
922
923 nfulnl_set_qthresh(inst, ntohl(qthresh));
924 }
925
926 if (nfula[NFULA_CFG_FLAGS])
927 nfulnl_set_flags(inst, flags);
928
929 out_put:
930 instance_put(inst);
931 out:
932 return ret;
933 }
934
935 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
936 [NFULNL_MSG_PACKET] = { .call = nfulnl_recv_unsupp,
937 .attr_count = NFULA_MAX, },
938 [NFULNL_MSG_CONFIG] = { .call = nfulnl_recv_config,
939 .attr_count = NFULA_CFG_MAX,
940 .policy = nfula_cfg_policy },
941 };
942
943 static const struct nfnetlink_subsystem nfulnl_subsys = {
944 .name = "log",
945 .subsys_id = NFNL_SUBSYS_ULOG,
946 .cb_count = NFULNL_MSG_MAX,
947 .cb = nfulnl_cb,
948 };
949
950 #ifdef CONFIG_PROC_FS
951 struct iter_state {
952 struct seq_net_private p;
953 unsigned int bucket;
954 };
955
956 static struct hlist_node *get_first(struct net *net, struct iter_state *st)
957 {
958 struct nfnl_log_net *log;
959 if (!st)
960 return NULL;
961
962 log = nfnl_log_pernet(net);
963
964 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
965 struct hlist_head *head = &log->instance_table[st->bucket];
966
967 if (!hlist_empty(head))
968 return rcu_dereference_bh(hlist_first_rcu(head));
969 }
970 return NULL;
971 }
972
973 static struct hlist_node *get_next(struct net *net, struct iter_state *st,
974 struct hlist_node *h)
975 {
976 h = rcu_dereference_bh(hlist_next_rcu(h));
977 while (!h) {
978 struct nfnl_log_net *log;
979 struct hlist_head *head;
980
981 if (++st->bucket >= INSTANCE_BUCKETS)
982 return NULL;
983
984 log = nfnl_log_pernet(net);
985 head = &log->instance_table[st->bucket];
986 h = rcu_dereference_bh(hlist_first_rcu(head));
987 }
988 return h;
989 }
990
991 static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
992 loff_t pos)
993 {
994 struct hlist_node *head;
995 head = get_first(net, st);
996
997 if (head)
998 while (pos && (head = get_next(net, st, head)))
999 pos--;
1000 return pos ? NULL : head;
1001 }
1002
1003 static void *seq_start(struct seq_file *s, loff_t *pos)
1004 __acquires(rcu_bh)
1005 {
1006 rcu_read_lock_bh();
1007 return get_idx(seq_file_net(s), s->private, *pos);
1008 }
1009
1010 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
1011 {
1012 (*pos)++;
1013 return get_next(seq_file_net(s), s->private, v);
1014 }
1015
1016 static void seq_stop(struct seq_file *s, void *v)
1017 __releases(rcu_bh)
1018 {
1019 rcu_read_unlock_bh();
1020 }
1021
1022 static int seq_show(struct seq_file *s, void *v)
1023 {
1024 const struct nfulnl_instance *inst = v;
1025
1026 seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1027 inst->group_num,
1028 inst->peer_portid, inst->qlen,
1029 inst->copy_mode, inst->copy_range,
1030 inst->flushtimeout, atomic_read(&inst->use));
1031
1032 return 0;
1033 }
1034
1035 static const struct seq_operations nful_seq_ops = {
1036 .start = seq_start,
1037 .next = seq_next,
1038 .stop = seq_stop,
1039 .show = seq_show,
1040 };
1041
1042 static int nful_open(struct inode *inode, struct file *file)
1043 {
1044 return seq_open_net(inode, file, &nful_seq_ops,
1045 sizeof(struct iter_state));
1046 }
1047
1048 static const struct file_operations nful_file_ops = {
1049 .owner = THIS_MODULE,
1050 .open = nful_open,
1051 .read = seq_read,
1052 .llseek = seq_lseek,
1053 .release = seq_release_net,
1054 };
1055
1056 #endif /* PROC_FS */
1057
1058 static int __net_init nfnl_log_net_init(struct net *net)
1059 {
1060 unsigned int i;
1061 struct nfnl_log_net *log = nfnl_log_pernet(net);
1062 #ifdef CONFIG_PROC_FS
1063 struct proc_dir_entry *proc;
1064 kuid_t root_uid;
1065 kgid_t root_gid;
1066 #endif
1067
1068 for (i = 0; i < INSTANCE_BUCKETS; i++)
1069 INIT_HLIST_HEAD(&log->instance_table[i]);
1070 spin_lock_init(&log->instances_lock);
1071
1072 #ifdef CONFIG_PROC_FS
1073 proc = proc_create("nfnetlink_log", 0440,
1074 net->nf.proc_netfilter, &nful_file_ops);
1075 if (!proc)
1076 return -ENOMEM;
1077
1078 root_uid = make_kuid(net->user_ns, 0);
1079 root_gid = make_kgid(net->user_ns, 0);
1080 if (uid_valid(root_uid) && gid_valid(root_gid))
1081 proc_set_user(proc, root_uid, root_gid);
1082 #endif
1083 return 0;
1084 }
1085
1086 static void __net_exit nfnl_log_net_exit(struct net *net)
1087 {
1088 #ifdef CONFIG_PROC_FS
1089 remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1090 #endif
1091 nf_log_unset(net, &nfulnl_logger);
1092 }
1093
1094 static struct pernet_operations nfnl_log_net_ops = {
1095 .init = nfnl_log_net_init,
1096 .exit = nfnl_log_net_exit,
1097 .id = &nfnl_log_net_id,
1098 .size = sizeof(struct nfnl_log_net),
1099 };
1100
1101 static int __init nfnetlink_log_init(void)
1102 {
1103 int status;
1104
1105 status = register_pernet_subsys(&nfnl_log_net_ops);
1106 if (status < 0) {
1107 pr_err("failed to register pernet ops\n");
1108 goto out;
1109 }
1110
1111 netlink_register_notifier(&nfulnl_rtnl_notifier);
1112 status = nfnetlink_subsys_register(&nfulnl_subsys);
1113 if (status < 0) {
1114 pr_err("failed to create netlink socket\n");
1115 goto cleanup_netlink_notifier;
1116 }
1117
1118 status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1119 if (status < 0) {
1120 pr_err("failed to register logger\n");
1121 goto cleanup_subsys;
1122 }
1123
1124 return status;
1125
1126 cleanup_subsys:
1127 nfnetlink_subsys_unregister(&nfulnl_subsys);
1128 cleanup_netlink_notifier:
1129 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1130 unregister_pernet_subsys(&nfnl_log_net_ops);
1131 out:
1132 return status;
1133 }
1134
1135 static void __exit nfnetlink_log_fini(void)
1136 {
1137 nf_log_unregister(&nfulnl_logger);
1138 nfnetlink_subsys_unregister(&nfulnl_subsys);
1139 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1140 unregister_pernet_subsys(&nfnl_log_net_ops);
1141 }
1142
1143 MODULE_DESCRIPTION("netfilter userspace logging");
1144 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1145 MODULE_LICENSE("GPL");
1146 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1147 MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1148 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1149 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1150 MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */
1151
1152 module_init(nfnetlink_log_init);
1153 module_exit(nfnetlink_log_fini);
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