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