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Linux/net/netfilter/nfnetlink_log.c

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

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