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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 <[email protected]>
7 * (C) 2006-2012 Patrick McHardy <[email protected]>
8 *
9 * Based on the old ipv4-only ipt_ULOG.c:
10 * (C) 2000-2004 by Harald Welte <[email protected]>
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
60struct nfulnl_instance {
61 struct hlist_node hlist; /* global list of instances */
62 spinlock_t lock;
63 refcount_t use; /* use count */
64
65 unsigned int qlen; /* number of nlmsgs in skb */
66 struct sk_buff *skb; /* pre-allocatd skb */
67 struct timer_list timer;
68 struct net *net;
69 netns_tracker ns_tracker;
70 struct user_namespace *peer_user_ns; /* User namespace of the peer process */
71 u32 peer_portid; /* PORTID of the peer process */
72
73 /* configurable parameters */
74 unsigned int flushtimeout; /* timeout until queue flush */
75 unsigned int nlbufsiz; /* netlink buffer allocation size */
76 unsigned int qthreshold; /* threshold of the queue */
77 u_int32_t copy_range;
78 u_int32_t seq; /* instance-local sequential counter */
79 u_int16_t group_num; /* number of this queue */
80 u_int16_t flags;
81 u_int8_t copy_mode;
82 struct rcu_head rcu;
83};
84
85#define INSTANCE_BUCKETS 16
86
87static unsigned int nfnl_log_net_id __read_mostly;
88
89struct nfnl_log_net {
90 spinlock_t instances_lock;
91 struct hlist_head instance_table[INSTANCE_BUCKETS];
92 atomic_t global_seq;
93};
94
95static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
96{
97 return net_generic(net, nfnl_log_net_id);
98}
99
100static inline u_int8_t instance_hashfn(u_int16_t group_num)
101{
102 return ((group_num & 0xff) % INSTANCE_BUCKETS);
103}
104
105static struct nfulnl_instance *
106__instance_lookup(const struct nfnl_log_net *log, u16 group_num)
107{
108 const struct hlist_head *head;
109 struct nfulnl_instance *inst;
110
111 head = &log->instance_table[instance_hashfn(group_num)];
112 hlist_for_each_entry_rcu(inst, head, hlist) {
113 if (inst->group_num == group_num)
114 return inst;
115 }
116 return NULL;
117}
118
119static inline void
120instance_get(struct nfulnl_instance *inst)
121{
122 refcount_inc(&inst->use);
123}
124
125static struct nfulnl_instance *
126instance_lookup_get_rcu(const struct nfnl_log_net *log, u16 group_num)
127{
128 struct nfulnl_instance *inst;
129
130 inst = __instance_lookup(log, group_num);
131 if (inst && !refcount_inc_not_zero(&inst->use))
132 inst = NULL;
133
134 return inst;
135}
136
137static struct nfulnl_instance *
138instance_lookup_get(const struct nfnl_log_net *log, u16 group_num)
139{
140 struct nfulnl_instance *inst;
141
142 rcu_read_lock();
143 inst = instance_lookup_get_rcu(log, group_num);
144 rcu_read_unlock();
145
146 return inst;
147}
148
149static void nfulnl_instance_free_rcu(struct rcu_head *head)
150{
151 struct nfulnl_instance *inst =
152 container_of(head, struct nfulnl_instance, rcu);
153
154 put_net_track(inst->net, &inst->ns_tracker);
155 kfree(inst);
156 module_put(THIS_MODULE);
157}
158
159static void
160instance_put(struct nfulnl_instance *inst)
161{
162 if (inst && refcount_dec_and_test(&inst->use))
163 call_rcu(&inst->rcu, nfulnl_instance_free_rcu);
164}
165
166static void nfulnl_timer(struct timer_list *t);
167
168static struct nfulnl_instance *
169instance_create(struct net *net, u_int16_t group_num,
170 u32 portid, struct user_namespace *user_ns)
171{
172 struct nfulnl_instance *inst;
173 struct nfnl_log_net *log = nfnl_log_pernet(net);
174 int err;
175
176 spin_lock_bh(&log->instances_lock);
177 if (__instance_lookup(log, group_num)) {
178 err = -EEXIST;
179 goto out_unlock;
180 }
181
182 inst = kzalloc_obj(*inst, GFP_ATOMIC);
183 if (!inst) {
184 err = -ENOMEM;
185 goto out_unlock;
186 }
187
188 if (!try_module_get(THIS_MODULE)) {
189 kfree(inst);
190 err = -EAGAIN;
191 goto out_unlock;
192 }
193
194 INIT_HLIST_NODE(&inst->hlist);
195 spin_lock_init(&inst->lock);
196 /* needs to be two, since we _put() after creation */
197 refcount_set(&inst->use, 2);
198
199 timer_setup(&inst->timer, nfulnl_timer, 0);
200
201 inst->net = get_net_track(net, &inst->ns_tracker, GFP_ATOMIC);
202 inst->peer_user_ns = user_ns;
203 inst->peer_portid = portid;
204 inst->group_num = group_num;
205
206 inst->qthreshold = NFULNL_QTHRESH_DEFAULT;
207 inst->flushtimeout = NFULNL_TIMEOUT_DEFAULT;
208 inst->nlbufsiz = NFULNL_NLBUFSIZ_DEFAULT;
209 inst->copy_mode = NFULNL_COPY_PACKET;
210 inst->copy_range = NFULNL_COPY_RANGE_MAX;
211
212 hlist_add_head_rcu(&inst->hlist,
213 &log->instance_table[instance_hashfn(group_num)]);
214
215
216 spin_unlock_bh(&log->instances_lock);
217
218 return inst;
219
220out_unlock:
221 spin_unlock_bh(&log->instances_lock);
222 return ERR_PTR(err);
223}
224
225static void __nfulnl_flush(struct nfulnl_instance *inst);
226
227/* called with BH disabled */
228static void
229__instance_destroy(struct nfulnl_instance *inst)
230{
231 spin_lock(&inst->lock);
232 if (inst->copy_mode == NFULNL_COPY_DISABLED) {
233 /* attempt to UNBIND a queue already pending
234 * destruction via netlink close event. Ignore.
235 */
236 spin_unlock(&inst->lock);
237 return;
238 }
239
240 /* first pull it out of the global list */
241 hlist_del_rcu(&inst->hlist);
242
243 /* lockless readers wont be able to use us */
244 inst->copy_mode = NFULNL_COPY_DISABLED;
245
246 if (inst->skb)
247 __nfulnl_flush(inst);
248 spin_unlock(&inst->lock);
249
250 /* and finally put the refcount */
251 instance_put(inst);
252}
253
254static inline void
255instance_destroy(struct nfnl_log_net *log,
256 struct nfulnl_instance *inst)
257{
258 spin_lock_bh(&log->instances_lock);
259 __instance_destroy(inst);
260 spin_unlock_bh(&log->instances_lock);
261}
262
263static int
264nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
265 unsigned int range)
266{
267 int status = 0;
268
269 spin_lock_bh(&inst->lock);
270
271 switch (mode) {
272 case NFULNL_COPY_NONE:
273 case NFULNL_COPY_META:
274 inst->copy_mode = mode;
275 inst->copy_range = 0;
276 break;
277
278 case NFULNL_COPY_PACKET:
279 inst->copy_mode = mode;
280 if (range == 0)
281 range = NFULNL_COPY_RANGE_MAX;
282 inst->copy_range = min_t(unsigned int,
283 range, NFULNL_COPY_RANGE_MAX);
284 break;
285
286 default:
287 status = -EINVAL;
288 break;
289 }
290
291 spin_unlock_bh(&inst->lock);
292
293 return status;
294}
295
296static int
297nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
298{
299 int status;
300
301 spin_lock_bh(&inst->lock);
302 if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
303 status = -ERANGE;
304 else if (nlbufsiz > 131072)
305 status = -ERANGE;
306 else {
307 inst->nlbufsiz = nlbufsiz;
308 status = 0;
309 }
310 spin_unlock_bh(&inst->lock);
311
312 return status;
313}
314
315static void
316nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
317{
318 spin_lock_bh(&inst->lock);
319 inst->flushtimeout = timeout;
320 spin_unlock_bh(&inst->lock);
321}
322
323static void
324nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
325{
326 spin_lock_bh(&inst->lock);
327 inst->qthreshold = qthresh;
328 spin_unlock_bh(&inst->lock);
329}
330
331static int
332nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
333{
334 spin_lock_bh(&inst->lock);
335 inst->flags = flags;
336 spin_unlock_bh(&inst->lock);
337
338 return 0;
339}
340
341static struct sk_buff *
342nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
343 unsigned int pkt_size)
344{
345 struct sk_buff *skb;
346 unsigned int n;
347
348 /* alloc skb which should be big enough for a whole multipart
349 * message. WARNING: has to be <= 128k due to slab restrictions */
350
351 n = max(inst_size, pkt_size);
352 skb = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN);
353 if (!skb) {
354 if (n > pkt_size) {
355 /* try to allocate only as much as we need for current
356 * packet */
357
358 skb = alloc_skb(pkt_size, GFP_ATOMIC);
359 }
360 }
361
362 return skb;
363}
364
365static void
366__nfulnl_send(struct nfulnl_instance *inst)
367{
368 if (inst->qlen > 1) {
369 struct nlmsghdr *nlh = nfnl_msg_put(inst->skb, 0, 0,
370 NLMSG_DONE, 0,
371 AF_UNSPEC, NFNETLINK_V0,
372 htons(inst->group_num));
373 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
374 inst->skb->len, skb_tailroom(inst->skb))) {
375 kfree_skb(inst->skb);
376 goto out;
377 }
378 }
379 nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid);
380out:
381 inst->qlen = 0;
382 inst->skb = NULL;
383}
384
385static void
386__nfulnl_flush(struct nfulnl_instance *inst)
387{
388 /* timer holds a reference */
389 if (timer_delete(&inst->timer))
390 instance_put(inst);
391 if (inst->skb)
392 __nfulnl_send(inst);
393}
394
395static void
396nfulnl_timer(struct timer_list *t)
397{
398 struct nfulnl_instance *inst = timer_container_of(inst, t, timer);
399
400 spin_lock_bh(&inst->lock);
401 if (inst->skb)
402 __nfulnl_send(inst);
403 spin_unlock_bh(&inst->lock);
404 instance_put(inst);
405}
406
407static u32 nfulnl_get_bridge_size(const struct sk_buff *skb)
408{
409 u32 mac_len, size = 0;
410
411 if (!skb_mac_header_was_set(skb))
412 return 0;
413
414 if (skb_vlan_tag_present(skb)) {
415 size += nla_total_size(0); /* nested */
416 size += nla_total_size(sizeof(u16)); /* id */
417 size += nla_total_size(sizeof(u16)); /* tag */
418 }
419
420 mac_len = skb_mac_header_len(skb);
421 if (mac_len > 0)
422 size += nla_total_size(mac_len);
423
424 return size;
425}
426
427static int nfulnl_put_bridge(struct nfulnl_instance *inst, const struct sk_buff *skb)
428{
429 u32 mac_len;
430
431 if (!skb_mac_header_was_set(skb))
432 return 0;
433
434 if (skb_vlan_tag_present(skb)) {
435 struct nlattr *nest;
436
437 nest = nla_nest_start(inst->skb, NFULA_VLAN);
438 if (!nest)
439 goto nla_put_failure;
440
441 if (nla_put_be16(inst->skb, NFULA_VLAN_TCI, htons(skb->vlan_tci)) ||
442 nla_put_be16(inst->skb, NFULA_VLAN_PROTO, skb->vlan_proto))
443 goto nla_put_failure;
444
445 nla_nest_end(inst->skb, nest);
446 }
447
448 mac_len = skb_mac_header_len(skb);
449 if (mac_len > 0 &&
450 nla_put(inst->skb, NFULA_L2HDR, mac_len, skb_mac_header(skb)))
451 goto nla_put_failure;
452
453 return 0;
454
455nla_put_failure:
456 return -1;
457}
458
459#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
460static int nflog_put_master_ifindex(struct sk_buff *nlskb, int attr,
461 const struct net_device *dev)
462{
463 const struct net_device *upper;
464
465 if (dev && !netif_is_bridge_port(dev))
466 return 0;
467
468 upper = netdev_master_upper_dev_get_rcu((struct net_device *)dev);
469 if (upper && nla_put_be32(nlskb, attr, htonl(upper->ifindex)))
470 return -EMSGSIZE;
471
472 return 0;
473}
474#endif
475
476/* This is an inline function, we don't really care about a long
477 * list of arguments */
478static inline int
479__build_packet_message(struct nfnl_log_net *log,
480 struct nfulnl_instance *inst,
481 const struct sk_buff *skb,
482 unsigned int data_len,
483 u_int8_t pf,
484 unsigned int hooknum,
485 const struct net_device *indev,
486 const struct net_device *outdev,
487 const char *prefix, unsigned int plen,
488 const struct nfnl_ct_hook *nfnl_ct,
489 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
490{
491 struct nfulnl_msg_packet_hdr pmsg;
492 struct nlmsghdr *nlh;
493 sk_buff_data_t old_tail = inst->skb->tail;
494 struct sock *sk;
495 const unsigned char *hwhdrp;
496
497 nlh = nfnl_msg_put(inst->skb, 0, 0,
498 nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET),
499 0, pf, NFNETLINK_V0, htons(inst->group_num));
500 if (!nlh)
501 return -1;
502
503 memset(&pmsg, 0, sizeof(pmsg));
504 pmsg.hw_protocol = skb->protocol;
505 pmsg.hook = hooknum;
506
507 if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
508 goto nla_put_failure;
509
510 if (prefix &&
511 nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
512 goto nla_put_failure;
513
514 if (indev) {
515#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
516 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
517 htonl(indev->ifindex)))
518 goto nla_put_failure;
519#else
520 if (pf == PF_BRIDGE) {
521 /* Case 1: outdev is physical input device, we need to
522 * look for bridge group (when called from
523 * netfilter_bridge) */
524 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
525 htonl(indev->ifindex)) ||
526 /* this is the bridge group "brX" */
527 /* rcu_read_lock()ed by nf_hook_thresh or
528 * nf_log_packet.
529 */
530 nflog_put_master_ifindex(inst->skb, NFULA_IFINDEX_INDEV, indev))
531 goto nla_put_failure;
532 } else {
533 int physinif;
534
535 /* Case 2: indev is bridge group, we need to look for
536 * physical device (when called from ipv4) */
537 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
538 htonl(indev->ifindex)))
539 goto nla_put_failure;
540
541 physinif = nf_bridge_get_physinif(skb);
542 if (physinif &&
543 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
544 htonl(physinif)))
545 goto nla_put_failure;
546 }
547#endif
548 }
549
550 if (outdev) {
551#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
552 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
553 htonl(outdev->ifindex)))
554 goto nla_put_failure;
555#else
556 if (pf == PF_BRIDGE) {
557 /* Case 1: outdev is physical output device, we need to
558 * look for bridge group (when called from
559 * netfilter_bridge) */
560 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
561 htonl(outdev->ifindex)) ||
562 /* this is the bridge group "brX" */
563 /* rcu_read_lock()ed by nf_hook_thresh or
564 * nf_log_packet.
565 */
566 nflog_put_master_ifindex(inst->skb, NFULA_IFINDEX_OUTDEV, outdev))
567 goto nla_put_failure;
568 } else {
569 struct net_device *physoutdev;
570
571 /* Case 2: indev is a bridge group, we need to look
572 * for physical device (when called from ipv4) */
573 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
574 htonl(outdev->ifindex)))
575 goto nla_put_failure;
576
577 physoutdev = nf_bridge_get_physoutdev(skb);
578 if (physoutdev &&
579 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
580 htonl(physoutdev->ifindex)))
581 goto nla_put_failure;
582 }
583#endif
584 }
585
586 if (skb->mark &&
587 nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
588 goto nla_put_failure;
589
590 if (indev && skb->dev &&
591 skb_mac_header_was_set(skb) &&
592 skb_mac_header_len(skb) != 0) {
593 struct nfulnl_msg_packet_hw phw;
594 int len;
595
596 memset(&phw, 0, sizeof(phw));
597 len = dev_parse_header(skb, phw.hw_addr);
598 if (len > 0) {
599 phw.hw_addrlen = htons(len);
600 if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
601 goto nla_put_failure;
602 }
603 }
604
605 if (indev && skb_mac_header_was_set(skb)) {
606 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
607 nla_put_be16(inst->skb, NFULA_HWLEN,
608 htons(skb->dev->hard_header_len)))
609 goto nla_put_failure;
610
611 hwhdrp = skb_mac_header(skb);
612
613 if (skb->dev->type == ARPHRD_SIT)
614 hwhdrp -= ETH_HLEN;
615
616 if (hwhdrp >= skb->head &&
617 nla_put(inst->skb, NFULA_HWHEADER,
618 skb->dev->hard_header_len, hwhdrp))
619 goto nla_put_failure;
620 }
621
622 if (hooknum <= NF_INET_FORWARD) {
623 struct timespec64 kts = ktime_to_timespec64(skb_tstamp_cond(skb, true));
624 struct nfulnl_msg_packet_timestamp ts;
625 ts.sec = cpu_to_be64(kts.tv_sec);
626 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
627
628 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
629 goto nla_put_failure;
630 }
631
632 /* UID */
633 sk = skb->sk;
634 if (sk && sk_fullsock(sk)) {
635 const struct socket *sock;
636 const struct file *file;
637
638 /* The sk pointer remains valid as long as the skb is.
639 * The sk_socket and file pointer may become NULL
640 * if the socket is closed.
641 * Both structures (including file->cred) are RCU freed
642 * which means they can be accessed within a RCU read section.
643 */
644 sock = READ_ONCE(sk->sk_socket);
645 file = sock ? READ_ONCE(sock->file) : NULL;
646 if (file) {
647 const struct cred *cred = file->f_cred;
648 struct user_namespace *user_ns = inst->peer_user_ns;
649 __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
650 __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
651 if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
652 nla_put_be32(inst->skb, NFULA_GID, gid))
653 goto nla_put_failure;
654 }
655 }
656
657 /* local sequence number */
658 if ((inst->flags & NFULNL_CFG_F_SEQ) &&
659 nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
660 goto nla_put_failure;
661
662 /* global sequence number */
663 if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
664 nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
665 htonl(atomic_inc_return(&log->global_seq))))
666 goto nla_put_failure;
667
668 if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
669 NFULA_CT, NFULA_CT_INFO) < 0)
670 goto nla_put_failure;
671
672 if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) &&
673 nfulnl_put_bridge(inst, skb) < 0)
674 goto nla_put_failure;
675
676 if (data_len) {
677 struct nlattr *nla;
678
679 nla = nla_reserve(inst->skb, NFULA_PAYLOAD, data_len);
680 if (!nla)
681 goto nla_put_failure;
682
683 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
684 goto nla_put_failure;
685 }
686
687 nlh->nlmsg_len = inst->skb->tail - old_tail;
688 return 0;
689
690nla_put_failure:
691 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
692 return -1;
693}
694
695static const struct nf_loginfo default_loginfo = {
696 .type = NF_LOG_TYPE_ULOG,
697 .u = {
698 .ulog = {
699 .copy_len = 0xffff,
700 .group = 0,
701 .qthreshold = 1,
702 },
703 },
704};
705
706static unsigned int nfulnl_get_copy_len(const struct nf_loginfo *li,
707 const struct sk_buff *skb,
708 unsigned int copy_len)
709{
710 unsigned int len = skb->len;
711
712 if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) &&
713 li->u.ulog.copy_len < copy_len)
714 copy_len = li->u.ulog.copy_len;
715 if (!skb_frags_readable(skb))
716 len = skb_headlen(skb);
717
718 return min(len, copy_len);
719}
720
721/* log handler for internal netfilter logging api */
722static void
723nfulnl_log_packet(struct net *net,
724 u_int8_t pf,
725 unsigned int hooknum,
726 const struct sk_buff *skb,
727 const struct net_device *in,
728 const struct net_device *out,
729 const struct nf_loginfo *li_user,
730 const char *prefix)
731{
732 size_t size;
733 unsigned int data_len;
734 struct nfulnl_instance *inst;
735 const struct nf_loginfo *li;
736 unsigned int qthreshold;
737 unsigned int plen = 0;
738 struct nfnl_log_net *log = nfnl_log_pernet(net);
739 const struct nfnl_ct_hook *nfnl_ct = NULL;
740 enum ip_conntrack_info ctinfo = 0;
741 struct nf_conn *ct = NULL;
742
743 if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
744 li = li_user;
745 else
746 li = &default_loginfo;
747
748 inst = instance_lookup_get_rcu(log, li->u.ulog.group);
749 if (!inst)
750 return;
751
752 if (prefix)
753 plen = strlen(prefix) + 1;
754
755 /* FIXME: do we want to make the size calculation conditional based on
756 * what is actually present? way more branches and checks, but more
757 * memory efficient... */
758 size = nlmsg_total_size(sizeof(struct nfgenmsg))
759 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
760 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
761 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
762#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
763 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
764 + nla_total_size(sizeof(u_int32_t)) /* ifindex */
765#endif
766 + nla_total_size(sizeof(u_int32_t)) /* mark */
767 + nla_total_size(sizeof(u_int32_t)) /* uid */
768 + nla_total_size(sizeof(u_int32_t)) /* gid */
769 + nla_total_size(plen) /* prefix */
770 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
771 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
772 + nlmsg_total_size(sizeof(struct nfgenmsg)); /* NLMSG_DONE */
773
774 if (in && skb_mac_header_was_set(skb)) {
775 size += nla_total_size(skb->dev->hard_header_len)
776 + nla_total_size(sizeof(u_int16_t)) /* hwtype */
777 + nla_total_size(sizeof(u_int16_t)); /* hwlen */
778 }
779
780 spin_lock_bh(&inst->lock);
781
782 if (inst->flags & NFULNL_CFG_F_SEQ)
783 size += nla_total_size(sizeof(u_int32_t));
784 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
785 size += nla_total_size(sizeof(u_int32_t));
786#if IS_ENABLED(CONFIG_NF_CONNTRACK)
787 if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
788 nfnl_ct = rcu_dereference(nfnl_ct_hook);
789 if (nfnl_ct != NULL) {
790 ct = nf_ct_get(skb, &ctinfo);
791 if (ct != NULL)
792 size += nfnl_ct->build_size(ct);
793 }
794 }
795#endif
796 if (pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE)
797 size += nfulnl_get_bridge_size(skb);
798
799 qthreshold = inst->qthreshold;
800 /* per-rule qthreshold overrides per-instance */
801 if (li->u.ulog.qthreshold)
802 if (qthreshold > li->u.ulog.qthreshold)
803 qthreshold = li->u.ulog.qthreshold;
804
805
806 switch (inst->copy_mode) {
807 case NFULNL_COPY_META:
808 case NFULNL_COPY_NONE:
809 data_len = 0;
810 break;
811
812 case NFULNL_COPY_PACKET:
813 data_len = nfulnl_get_copy_len(li, skb, inst->copy_range);
814 size += nla_total_size(data_len);
815 break;
816
817 case NFULNL_COPY_DISABLED:
818 default:
819 goto unlock_and_release;
820 }
821
822 if (inst->skb && size > skb_tailroom(inst->skb)) {
823 /* either the queue len is too high or we don't have
824 * enough room in the skb left. flush to userspace. */
825 __nfulnl_flush(inst);
826 }
827
828 if (!inst->skb) {
829 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
830 inst->nlbufsiz, size);
831 if (!inst->skb)
832 goto alloc_failure;
833 }
834
835 inst->qlen++;
836
837 __build_packet_message(log, inst, skb, data_len, pf,
838 hooknum, in, out, prefix, plen,
839 nfnl_ct, ct, ctinfo);
840
841 if (inst->qlen >= qthreshold)
842 __nfulnl_flush(inst);
843 /* timer_pending always called within inst->lock, so there
844 * is no chance of a race here */
845 else if (!timer_pending(&inst->timer)) {
846 instance_get(inst);
847 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
848 add_timer(&inst->timer);
849 }
850
851unlock_and_release:
852 spin_unlock_bh(&inst->lock);
853 instance_put(inst);
854 return;
855
856alloc_failure:
857 /* FIXME: statistics */
858 goto unlock_and_release;
859}
860
861static int
862nfulnl_rcv_nl_event(struct notifier_block *this,
863 unsigned long event, void *ptr)
864{
865 struct netlink_notify *n = ptr;
866 struct nfnl_log_net *log = nfnl_log_pernet(n->net);
867
868 if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
869 int i;
870
871 /* destroy all instances for this portid */
872 spin_lock_bh(&log->instances_lock);
873 for (i = 0; i < INSTANCE_BUCKETS; i++) {
874 struct hlist_node *t2;
875 struct nfulnl_instance *inst;
876 struct hlist_head *head = &log->instance_table[i];
877
878 hlist_for_each_entry_safe(inst, t2, head, hlist) {
879 if (n->portid == inst->peer_portid)
880 __instance_destroy(inst);
881 }
882 }
883 spin_unlock_bh(&log->instances_lock);
884 }
885 return NOTIFY_DONE;
886}
887
888static struct notifier_block nfulnl_rtnl_notifier = {
889 .notifier_call = nfulnl_rcv_nl_event,
890};
891
892static int nfulnl_recv_unsupp(struct sk_buff *skb, const struct nfnl_info *info,
893 const struct nlattr * const nfula[])
894{
895 return -ENOTSUPP;
896}
897
898static struct nf_logger nfulnl_logger __read_mostly = {
899 .name = "nfnetlink_log",
900 .type = NF_LOG_TYPE_ULOG,
901 .logfn = nfulnl_log_packet,
902 .me = THIS_MODULE,
903};
904
905static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
906 [NFULA_CFG_CMD] = { .len = sizeof(struct nfulnl_msg_config_cmd) },
907 [NFULA_CFG_MODE] = { .len = sizeof(struct nfulnl_msg_config_mode) },
908 [NFULA_CFG_TIMEOUT] = { .type = NLA_U32 },
909 [NFULA_CFG_QTHRESH] = { .type = NLA_U32 },
910 [NFULA_CFG_NLBUFSIZ] = { .type = NLA_U32 },
911 [NFULA_CFG_FLAGS] = NLA_POLICY_MASK(NLA_BE16, NFULNL_CFG_F_SEQ |
912 NFULNL_CFG_F_SEQ_GLOBAL |
913 NFULNL_CFG_F_CONNTRACK),
914};
915
916static int nfulnl_recv_config(struct sk_buff *skb, const struct nfnl_info *info,
917 const struct nlattr * const nfula[])
918{
919 struct nfnl_log_net *log = nfnl_log_pernet(info->net);
920 u_int16_t group_num = ntohs(info->nfmsg->res_id);
921 struct nfulnl_msg_config_cmd *cmd = NULL;
922 struct nfulnl_instance *inst;
923 u16 flags = 0;
924 int ret = 0;
925
926 if (nfula[NFULA_CFG_CMD]) {
927 u_int8_t pf = info->nfmsg->nfgen_family;
928 cmd = nla_data(nfula[NFULA_CFG_CMD]);
929
930 /* Commands without queue context */
931 switch (cmd->command) {
932 case NFULNL_CFG_CMD_PF_BIND:
933 return nf_log_bind_pf(info->net, pf, &nfulnl_logger);
934 case NFULNL_CFG_CMD_PF_UNBIND:
935 nf_log_unbind_pf(info->net, pf);
936 return 0;
937 }
938 }
939
940 inst = instance_lookup_get(log, group_num);
941 if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
942 ret = -EPERM;
943 goto out_put;
944 }
945
946 /* Check if we support these flags in first place, dependencies should
947 * be there too not to break atomicity.
948 */
949 if (nfula[NFULA_CFG_FLAGS]) {
950 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
951
952 if ((flags & NFULNL_CFG_F_CONNTRACK) &&
953 !rcu_access_pointer(nfnl_ct_hook)) {
954#ifdef CONFIG_MODULES
955 nfnl_unlock(NFNL_SUBSYS_ULOG);
956 request_module("ip_conntrack_netlink");
957 nfnl_lock(NFNL_SUBSYS_ULOG);
958 if (rcu_access_pointer(nfnl_ct_hook)) {
959 ret = -EAGAIN;
960 goto out_put;
961 }
962#endif
963 ret = -EOPNOTSUPP;
964 goto out_put;
965 }
966 }
967
968 if (cmd != NULL) {
969 switch (cmd->command) {
970 case NFULNL_CFG_CMD_BIND:
971 if (inst) {
972 ret = -EBUSY;
973 goto out_put;
974 }
975
976 inst = instance_create(info->net, group_num,
977 NETLINK_CB(skb).portid,
978 sk_user_ns(NETLINK_CB(skb).sk));
979 if (IS_ERR(inst)) {
980 ret = PTR_ERR(inst);
981 goto out;
982 }
983 break;
984 case NFULNL_CFG_CMD_UNBIND:
985 if (!inst) {
986 ret = -ENODEV;
987 goto out;
988 }
989
990 instance_destroy(log, inst);
991 goto out_put;
992 default:
993 ret = -ENOTSUPP;
994 goto out_put;
995 }
996 } else if (!inst) {
997 ret = -ENODEV;
998 goto out;
999 }
1000
1001 if (nfula[NFULA_CFG_MODE]) {
1002 struct nfulnl_msg_config_mode *params =
1003 nla_data(nfula[NFULA_CFG_MODE]);
1004
1005 nfulnl_set_mode(inst, params->copy_mode,
1006 ntohl(params->copy_range));
1007 }
1008
1009 if (nfula[NFULA_CFG_TIMEOUT]) {
1010 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
1011
1012 nfulnl_set_timeout(inst, ntohl(timeout));
1013 }
1014
1015 if (nfula[NFULA_CFG_NLBUFSIZ]) {
1016 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
1017
1018 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
1019 }
1020
1021 if (nfula[NFULA_CFG_QTHRESH]) {
1022 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
1023
1024 nfulnl_set_qthresh(inst, ntohl(qthresh));
1025 }
1026
1027 if (nfula[NFULA_CFG_FLAGS])
1028 nfulnl_set_flags(inst, flags);
1029
1030out_put:
1031 instance_put(inst);
1032out:
1033 return ret;
1034}
1035
1036static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
1037 [NFULNL_MSG_PACKET] = {
1038 .call = nfulnl_recv_unsupp,
1039 .type = NFNL_CB_MUTEX,
1040 .attr_count = NFULA_MAX,
1041 },
1042 [NFULNL_MSG_CONFIG] = {
1043 .call = nfulnl_recv_config,
1044 .type = NFNL_CB_MUTEX,
1045 .attr_count = NFULA_CFG_MAX,
1046 .policy = nfula_cfg_policy
1047 },
1048};
1049
1050static const struct nfnetlink_subsystem nfulnl_subsys = {
1051 .name = "log",
1052 .subsys_id = NFNL_SUBSYS_ULOG,
1053 .cb_count = NFULNL_MSG_MAX,
1054 .cb = nfulnl_cb,
1055};
1056
1057#ifdef CONFIG_PROC_FS
1058struct iter_state {
1059 struct seq_net_private p;
1060 unsigned int bucket;
1061};
1062
1063static struct hlist_node *get_first(struct net *net, struct iter_state *st)
1064{
1065 struct nfnl_log_net *log;
1066 if (!st)
1067 return NULL;
1068
1069 log = nfnl_log_pernet(net);
1070
1071 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
1072 struct hlist_head *head = &log->instance_table[st->bucket];
1073
1074 if (!hlist_empty(head))
1075 return rcu_dereference(hlist_first_rcu(head));
1076 }
1077 return NULL;
1078}
1079
1080static struct hlist_node *get_next(struct net *net, struct iter_state *st,
1081 struct hlist_node *h)
1082{
1083 h = rcu_dereference(hlist_next_rcu(h));
1084 while (!h) {
1085 struct nfnl_log_net *log;
1086 struct hlist_head *head;
1087
1088 if (++st->bucket >= INSTANCE_BUCKETS)
1089 return NULL;
1090
1091 log = nfnl_log_pernet(net);
1092 head = &log->instance_table[st->bucket];
1093 h = rcu_dereference(hlist_first_rcu(head));
1094 }
1095 return h;
1096}
1097
1098static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
1099 loff_t pos)
1100{
1101 struct hlist_node *head;
1102 head = get_first(net, st);
1103
1104 if (head)
1105 while (pos && (head = get_next(net, st, head)))
1106 pos--;
1107 return pos ? NULL : head;
1108}
1109
1110static void *seq_start(struct seq_file *s, loff_t *pos)
1111 __acquires(rcu)
1112{
1113 rcu_read_lock();
1114 return get_idx(seq_file_net(s), s->private, *pos);
1115}
1116
1117static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
1118{
1119 (*pos)++;
1120 return get_next(seq_file_net(s), s->private, v);
1121}
1122
1123static void seq_stop(struct seq_file *s, void *v)
1124 __releases(rcu)
1125{
1126 rcu_read_unlock();
1127}
1128
1129static int seq_show(struct seq_file *s, void *v)
1130{
1131 const struct nfulnl_instance *inst = v;
1132
1133 seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1134 inst->group_num,
1135 inst->peer_portid, inst->qlen,
1136 inst->copy_mode, inst->copy_range,
1137 inst->flushtimeout, refcount_read(&inst->use));
1138
1139 return 0;
1140}
1141
1142static const struct seq_operations nful_seq_ops = {
1143 .start = seq_start,
1144 .next = seq_next,
1145 .stop = seq_stop,
1146 .show = seq_show,
1147};
1148#endif /* PROC_FS */
1149
1150static int __net_init nfnl_log_net_init(struct net *net)
1151{
1152 unsigned int i;
1153 struct nfnl_log_net *log = nfnl_log_pernet(net);
1154#ifdef CONFIG_PROC_FS
1155 struct proc_dir_entry *proc;
1156 kuid_t root_uid;
1157 kgid_t root_gid;
1158#endif
1159
1160 for (i = 0; i < INSTANCE_BUCKETS; i++)
1161 INIT_HLIST_HEAD(&log->instance_table[i]);
1162 spin_lock_init(&log->instances_lock);
1163
1164#ifdef CONFIG_PROC_FS
1165 proc = proc_create_net("nfnetlink_log", 0440, net->nf.proc_netfilter,
1166 &nful_seq_ops, sizeof(struct iter_state));
1167 if (!proc)
1168 return -ENOMEM;
1169
1170 root_uid = make_kuid(net->user_ns, 0);
1171 root_gid = make_kgid(net->user_ns, 0);
1172 if (uid_valid(root_uid) && gid_valid(root_gid))
1173 proc_set_user(proc, root_uid, root_gid);
1174#endif
1175 return 0;
1176}
1177
1178static void __net_exit nfnl_log_net_pre_exit(struct net *net)
1179{
1180#ifdef CONFIG_PROC_FS
1181 remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1182#endif
1183 nf_log_unset(net, &nfulnl_logger);
1184}
1185
1186static void __net_exit nfnl_log_net_exit(struct net *net)
1187{
1188 struct nfnl_log_net *log = nfnl_log_pernet(net);
1189 unsigned int i;
1190
1191 for (i = 0; i < INSTANCE_BUCKETS; i++)
1192 WARN_ON_ONCE(!hlist_empty(&log->instance_table[i]));
1193}
1194
1195static struct pernet_operations nfnl_log_net_ops = {
1196 .init = nfnl_log_net_init,
1197 .pre_exit = nfnl_log_net_pre_exit,
1198 .exit = nfnl_log_net_exit,
1199 .id = &nfnl_log_net_id,
1200 .size = sizeof(struct nfnl_log_net),
1201};
1202
1203static int __init nfnetlink_log_init(void)
1204{
1205 int status;
1206
1207 status = register_pernet_subsys(&nfnl_log_net_ops);
1208 if (status < 0) {
1209 pr_err("failed to register pernet ops\n");
1210 goto out;
1211 }
1212
1213 netlink_register_notifier(&nfulnl_rtnl_notifier);
1214 status = nfnetlink_subsys_register(&nfulnl_subsys);
1215 if (status < 0) {
1216 pr_err("failed to create netlink socket\n");
1217 goto cleanup_netlink_notifier;
1218 }
1219
1220 status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1221 if (status < 0) {
1222 pr_err("failed to register logger\n");
1223 goto cleanup_subsys;
1224 }
1225
1226 return status;
1227
1228cleanup_subsys:
1229 nfnetlink_subsys_unregister(&nfulnl_subsys);
1230cleanup_netlink_notifier:
1231 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1232 unregister_pernet_subsys(&nfnl_log_net_ops);
1233out:
1234 return status;
1235}
1236
1237static void __exit nfnetlink_log_fini(void)
1238{
1239 nfnetlink_subsys_unregister(&nfulnl_subsys);
1240 netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1241 nf_log_unregister(&nfulnl_logger);
1242 unregister_pernet_subsys(&nfnl_log_net_ops);
1243}
1244
1245MODULE_DESCRIPTION("netfilter userspace logging");
1246MODULE_AUTHOR("Harald Welte <[email protected]>");
1247MODULE_LICENSE("GPL");
1248MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1249MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1250MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1251MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1252MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */
1253MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */
1254
1255module_init(nfnetlink_log_init);
1256module_exit(nfnetlink_log_fini);