net/netfilter/nfnetlink_log.c

   1 /*
   2  * This is a module which is used for logging packets to userspace via
   3  * nfetlink.
   4  *
   5  * (C) 2005 by Harald Welte <laforge@netfilter.org>
   6  * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
   7  *
   8  * Based on the old ipv4-only ipt_ULOG.c:
   9  * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18 #include <linux/module.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/if_arp.h>
  21 #include <linux/init.h>
  22 #include <linux/ip.h>
  23 #include <linux/ipv6.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/netfilter.h>
  26 #include <linux/netfilter_bridge.h>
  27 #include <net/netlink.h>
  28 #include <linux/netfilter/nfnetlink.h>
  29 #include <linux/netfilter/nfnetlink_log.h>
  30 #include <linux/netfilter/nf_conntrack_common.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/sysctl.h>
  33 #include <linux/proc_fs.h>
  34 #include <linux/security.h>
  35 #include <linux/list.h>
  36 #include <linux/slab.h>
  37 #include <net/sock.h>
  38 #include <net/netfilter/nf_log.h>
  39 #include <net/netns/generic.h>
  40 #include <net/netfilter/nfnetlink_log.h>
  41
  42 #include <linux/atomic.h>
  43
  44 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
  45 #include "../bridge/br_private.h"
  46 #endif
  47
  48 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  49 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  50 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  51 /* max packet size is limited by 16-bit struct nfattr nfa_len field */
  52 #define NFULNL_COPY_RANGE_MAX   (0xFFFF - NLA_HDRLEN)
  53
  54 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  55                                      printk(x, ## args); } while (0);
  56
  57 struct nfulnl_instance {
  58         struct hlist_node hlist;        /* global list of instances */
  59         spinlock_t lock;
  60         atomic_t use;                   /* use count */
  61
  62         unsigned int qlen;              /* number of nlmsgs in skb */
  63         struct sk_buff *skb;            /* pre-allocatd skb */
  64         struct timer_list timer;
  65         struct net *net;
  66         struct user_namespace *peer_user_ns;    /* User namespace of the peer process */
  67         u32 peer_portid;                /* PORTID of the peer process */
  68
  69         /* configurable parameters */
  70         unsigned int flushtimeout;      /* timeout until queue flush */
  71         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  72         unsigned int qthreshold;        /* threshold of the queue */
  73         u_int32_t copy_range;
  74         u_int32_t seq;                  /* instance-local sequential counter */
  75         u_int16_t group_num;            /* number of this queue */
  76         u_int16_t flags;
  77         u_int8_t copy_mode;
  78         struct rcu_head rcu;
  79 };
  80
  81 #define INSTANCE_BUCKETS        16
  82
  83 static int nfnl_log_net_id __read_mostly;
  84
  85 struct nfnl_log_net {
  86         spinlock_t instances_lock;
  87         struct hlist_head instance_table[INSTANCE_BUCKETS];
  88         atomic_t global_seq;
  89 };
  90
  91 static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
  92 {
  93         return net_generic(net, nfnl_log_net_id);
  94 }
  95
  96 static inline u_int8_t instance_hashfn(u_int16_t group_num)
  97 {
  98         return ((group_num & 0xff) % INSTANCE_BUCKETS);
  99 }
 100
 101 static struct nfulnl_instance *
 102 __instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
 103 {
 104         struct hlist_head *head;
 105         struct nfulnl_instance *inst;
 106
 107         head = &log->instance_table[instance_hashfn(group_num)];
 108         hlist_for_each_entry_rcu(inst, head, hlist) {
 109                 if (inst->group_num == group_num)
 110                         return inst;
 111         }
 112         return NULL;
 113 }
 114
 115 static inline void
 116 instance_get(struct nfulnl_instance *inst)
 117 {
 118         atomic_inc(&inst->use);
 119 }
 120
 121 static struct nfulnl_instance *
 122 instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
 123 {
 124         struct nfulnl_instance *inst;
 125
 126         rcu_read_lock_bh();
 127         inst = __instance_lookup(log, group_num);
 128         if (inst && !atomic_inc_not_zero(&inst->use))
 129                 inst = NULL;
 130         rcu_read_unlock_bh();
 131
 132         return inst;
 133 }
 134
 135 static void nfulnl_instance_free_rcu(struct rcu_head *head)
 136 {
 137         struct nfulnl_instance *inst =
 138                 container_of(head, struct nfulnl_instance, rcu);
 139
 140         put_net(inst->net);
 141         kfree(inst);
 142         module_put(THIS_MODULE);
 143 }
 144
 145 static void
 146 instance_put(struct nfulnl_instance *inst)
 147 {
 148         if (inst && atomic_dec_and_test(&inst->use))
 149                 call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
 150 }
 151
 152 static void nfulnl_timer(unsigned long data);
 153
 154 static struct nfulnl_instance *
 155 instance_create(struct net *net, u_int16_t group_num,
 156                 u32 portid, struct user_namespace *user_ns)
 157 {
 158         struct nfulnl_instance *inst;
 159         struct nfnl_log_net *log = nfnl_log_pernet(net);
 160         int err;
 161
 162         spin_lock_bh(&log->instances_lock);
 163         if (__instance_lookup(log, group_num)) {
 164                 err = -EEXIST;
 165                 goto out_unlock;
 166         }
 167
 168         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 169         if (!inst) {
 170                 err = -ENOMEM;
 171                 goto out_unlock;
 172         }
 173
 174         if (!try_module_get(THIS_MODULE)) {
 175                 kfree(inst);
 176                 err = -EAGAIN;
 177                 goto out_unlock;
 178         }
 179
 180         INIT_HLIST_NODE(&inst->hlist);
 181         spin_lock_init(&inst->lock);
 182         /* needs to be two, since we _put() after creation */
 183         atomic_set(&inst->use, 2);
 184
 185         setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
 186
 187         inst->net = get_net(net);
 188         inst->peer_user_ns = user_ns;
 189         inst->peer_portid = portid;
 190         inst->group_num = group_num;
 191
 192         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 193         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 194         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 195         inst->copy_mode         = NFULNL_COPY_PACKET;
 196         inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 197
 198         hlist_add_head_rcu(&inst->hlist,
 199                        &log->instance_table[instance_hashfn(group_num)]);
 200
 201
 202         spin_unlock_bh(&log->instances_lock);
 203
 204         return inst;
 205
 206 out_unlock:
 207         spin_unlock_bh(&log->instances_lock);
 208         return ERR_PTR(err);
 209 }
 210
 211 static void __nfulnl_flush(struct nfulnl_instance *inst);
 212
 213 /* called with BH disabled */
 214 static void
 215 __instance_destroy(struct nfulnl_instance *inst)
 216 {
 217         /* first pull it out of the global list */
 218         hlist_del_rcu(&inst->hlist);
 219
 220         /* then flush all pending packets from skb */
 221
 222         spin_lock(&inst->lock);
 223
 224         /* lockless readers wont be able to use us */
 225         inst->copy_mode = NFULNL_COPY_DISABLED;
 226
 227         if (inst->skb)
 228                 __nfulnl_flush(inst);
 229         spin_unlock(&inst->lock);
 230
 231         /* and finally put the refcount */
 232         instance_put(inst);
 233 }
 234
 235 static inline void
 236 instance_destroy(struct nfnl_log_net *log,
 237                  struct nfulnl_instance *inst)
 238 {
 239         spin_lock_bh(&log->instances_lock);
 240         __instance_destroy(inst);
 241         spin_unlock_bh(&log->instances_lock);
 242 }
 243
 244 static int
 245 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 246                   unsigned int range)
 247 {
 248         int status = 0;
 249
 250         spin_lock_bh(&inst->lock);
 251
 252         switch (mode) {
 253         case NFULNL_COPY_NONE:
 254         case NFULNL_COPY_META:
 255                 inst->copy_mode = mode;
 256                 inst->copy_range = 0;
 257                 break;
 258
 259         case NFULNL_COPY_PACKET:
 260                 inst->copy_mode = mode;
 261                 if (range == 0)
 262                         range = NFULNL_COPY_RANGE_MAX;
 263                 inst->copy_range = min_t(unsigned int,
 264                                          range, NFULNL_COPY_RANGE_MAX);
 265                 break;
 266
 267         default:
 268                 status = -EINVAL;
 269                 break;
 270         }
 271
 272         spin_unlock_bh(&inst->lock);
 273
 274         return status;
 275 }
 276
 277 static int
 278 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 279 {
 280         int status;
 281
 282         spin_lock_bh(&inst->lock);
 283         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 284                 status = -ERANGE;
 285         else if (nlbufsiz > 131072)
 286                 status = -ERANGE;
 287         else {
 288                 inst->nlbufsiz = nlbufsiz;
 289                 status = 0;
 290         }
 291         spin_unlock_bh(&inst->lock);
 292
 293         return status;
 294 }
 295
 296 static void
 297 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 298 {
 299         spin_lock_bh(&inst->lock);
 300         inst->flushtimeout = timeout;
 301         spin_unlock_bh(&inst->lock);
 302 }
 303
 304 static void
 305 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 306 {
 307         spin_lock_bh(&inst->lock);
 308         inst->qthreshold = qthresh;
 309         spin_unlock_bh(&inst->lock);
 310 }
 311
 312 static int
 313 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 314 {
 315         spin_lock_bh(&inst->lock);
 316         inst->flags = flags;
 317         spin_unlock_bh(&inst->lock);
 318
 319         return 0;
 320 }
 321
 322 static struct sk_buff *
 323 nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
 324                  unsigned int pkt_size)
 325 {
 326         struct sk_buff *skb;
 327         unsigned int n;
 328
 329         /* alloc skb which should be big enough for a whole multipart
 330          * message.  WARNING: has to be <= 128k due to slab restrictions */
 331
 332         n = max(inst_size, pkt_size);
 333         skb = alloc_skb(n, GFP_ATOMIC);
 334         if (!skb) {
 335                 if (n > pkt_size) {
 336                         /* try to allocate only as much as we need for current
 337                          * packet */
 338
 339                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
 340                 }
 341         }
 342
 343         return skb;
 344 }
 345
 346 static void
 347 __nfulnl_send(struct nfulnl_instance *inst)
 348 {
 349         if (inst->qlen > 1) {
 350                 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 351                                                  NLMSG_DONE,
 352                                                  sizeof(struct nfgenmsg),
 353                                                  0);
 354                 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
 355                               inst->skb->len, skb_tailroom(inst->skb))) {
 356                         kfree_skb(inst->skb);
 357                         goto out;
 358                 }
 359         }
 360         nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
 361                           MSG_DONTWAIT);
 362 out:
 363         inst->qlen = 0;
 364         inst->skb = NULL;
 365 }
 366
 367 static void
 368 __nfulnl_flush(struct nfulnl_instance *inst)
 369 {
 370         /* timer holds a reference */
 371         if (del_timer(&inst->timer))
 372                 instance_put(inst);
 373         if (inst->skb)
 374                 __nfulnl_send(inst);
 375 }
 376
 377 static void
 378 nfulnl_timer(unsigned long data)
 379 {
 380         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 381
 382         spin_lock_bh(&inst->lock);
 383         if (inst->skb)
 384                 __nfulnl_send(inst);
 385         spin_unlock_bh(&inst->lock);
 386         instance_put(inst);
 387 }
 388
 389 /* This is an inline function, we don't really care about a long
 390  * list of arguments */
 391 static inline int
 392 __build_packet_message(struct nfnl_log_net *log,
 393                         struct nfulnl_instance *inst,
 394                         const struct sk_buff *skb,
 395                         unsigned int data_len,
 396                         u_int8_t pf,
 397                         unsigned int hooknum,
 398                         const struct net_device *indev,
 399                         const struct net_device *outdev,
 400                         const char *prefix, unsigned int plen,
 401                         const struct nfnl_ct_hook *nfnl_ct,
 402                         struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 403 {
 404         struct nfulnl_msg_packet_hdr pmsg;
 405         struct nlmsghdr *nlh;
 406         struct nfgenmsg *nfmsg;
 407         sk_buff_data_t old_tail = inst->skb->tail;
 408         struct sock *sk;
 409         const unsigned char *hwhdrp;
 410
 411         nlh = nlmsg_put(inst->skb, 0, 0,
 412                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 413                         sizeof(struct nfgenmsg), 0);
 414         if (!nlh)
 415                 return -1;
 416         nfmsg = nlmsg_data(nlh);
 417         nfmsg->nfgen_family = pf;
 418         nfmsg->version = NFNETLINK_V0;
 419         nfmsg->res_id = htons(inst->group_num);
 420
 421         memset(&pmsg, 0, sizeof(pmsg));
 422         pmsg.hw_protocol        = skb->protocol;
 423         pmsg.hook               = hooknum;
 424
 425         if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
 426                 goto nla_put_failure;
 427
 428         if (prefix &&
 429             nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
 430                 goto nla_put_failure;
 431
 432         if (indev) {
 433 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 434                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 435                                  htonl(indev->ifindex)))
 436                         goto nla_put_failure;
 437 #else
 438                 if (pf == PF_BRIDGE) {
 439                         /* Case 1: outdev is physical input device, we need to
 440                          * look for bridge group (when called from
 441                          * netfilter_bridge) */
 442                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 443                                          htonl(indev->ifindex)) ||
 444                         /* this is the bridge group "brX" */
 445                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 446                             nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 447                                          htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 448                                 goto nla_put_failure;
 449                 } else {
 450                         struct net_device *physindev;
 451
 452                         /* Case 2: indev is bridge group, we need to look for
 453                          * physical device (when called from ipv4) */
 454                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 455                                          htonl(indev->ifindex)))
 456                                 goto nla_put_failure;
 457
 458                         physindev = nf_bridge_get_physindev(skb);
 459                         if (physindev &&
 460                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 461                                          htonl(physindev->ifindex)))
 462                                 goto nla_put_failure;
 463                 }
 464 #endif
 465         }
 466
 467         if (outdev) {
 468 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 469                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 470                                  htonl(outdev->ifindex)))
 471                         goto nla_put_failure;
 472 #else
 473                 if (pf == PF_BRIDGE) {
 474                         /* Case 1: outdev is physical output device, we need to
 475                          * look for bridge group (when called from
 476                          * netfilter_bridge) */
 477                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 478                                          htonl(outdev->ifindex)) ||
 479                         /* this is the bridge group "brX" */
 480                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 481                             nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 482                                          htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 483                                 goto nla_put_failure;
 484                 } else {
 485                         struct net_device *physoutdev;
 486
 487                         /* Case 2: indev is a bridge group, we need to look
 488                          * for physical device (when called from ipv4) */
 489                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 490                                          htonl(outdev->ifindex)))
 491                                 goto nla_put_failure;
 492
 493                         physoutdev = nf_bridge_get_physoutdev(skb);
 494                         if (physoutdev &&
 495                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 496                                          htonl(physoutdev->ifindex)))
 497                                 goto nla_put_failure;
 498                 }
 499 #endif
 500         }
 501
 502         if (skb->mark &&
 503             nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
 504                 goto nla_put_failure;
 505
 506         if (indev && skb->dev &&
 507             skb->mac_header != skb->network_header) {
 508                 struct nfulnl_msg_packet_hw phw;
 509                 int len;
 510
 511                 memset(&phw, 0, sizeof(phw));
 512                 len = dev_parse_header(skb, phw.hw_addr);
 513                 if (len > 0) {
 514                         phw.hw_addrlen = htons(len);
 515                         if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 516                                 goto nla_put_failure;
 517                 }
 518         }
 519
 520         if (indev && skb_mac_header_was_set(skb)) {
 521                 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 522                     nla_put_be16(inst->skb, NFULA_HWLEN,
 523                                  htons(skb->dev->hard_header_len)))
 524                         goto nla_put_failure;
 525
 526                 hwhdrp = skb_mac_header(skb);
 527
 528                 if (skb->dev->type == ARPHRD_SIT)
 529                         hwhdrp -= ETH_HLEN;
 530
 531                 if (hwhdrp >= skb->head &&
 532                     nla_put(inst->skb, NFULA_HWHEADER,
 533                             skb->dev->hard_header_len, hwhdrp))
 534                         goto nla_put_failure;
 535         }
 536
 537         if (skb->tstamp.tv64) {
 538                 struct nfulnl_msg_packet_timestamp ts;
 539                 struct timespec64 kts = ktime_to_timespec64(skb->tstamp);
 540                 ts.sec = cpu_to_be64(kts.tv_sec);
 541                 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
 542
 543                 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 544                         goto nla_put_failure;
 545         }
 546
 547         /* UID */
 548         sk = skb->sk;
 549         if (sk && sk_fullsock(sk)) {
 550                 read_lock_bh(&sk->sk_callback_lock);
 551                 if (sk->sk_socket && sk->sk_socket->file) {
 552                         struct file *file = sk->sk_socket->file;
 553                         const struct cred *cred = file->f_cred;
 554                         struct user_namespace *user_ns = inst->peer_user_ns;
 555                         __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
 556                         __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
 557                         read_unlock_bh(&sk->sk_callback_lock);
 558                         if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 559                             nla_put_be32(inst->skb, NFULA_GID, gid))
 560                                 goto nla_put_failure;
 561                 } else
 562                         read_unlock_bh(&sk->sk_callback_lock);
 563         }
 564
 565         /* local sequence number */
 566         if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 567             nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 568                 goto nla_put_failure;
 569
 570         /* global sequence number */
 571         if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 572             nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 573                          htonl(atomic_inc_return(&log->global_seq))))
 574                 goto nla_put_failure;
 575
 576         if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
 577                                  NFULA_CT, NFULA_CT_INFO) < 0)
 578                 goto nla_put_failure;
 579
 580         if (data_len) {
 581                 struct nlattr *nla;
 582                 int size = nla_attr_size(data_len);
 583
 584                 if (skb_tailroom(inst->skb) < nla_total_size(data_len))
 585                         goto nla_put_failure;
 586
 587                 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
 588                 nla->nla_type = NFULA_PAYLOAD;
 589                 nla->nla_len = size;
 590
 591                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 592                         BUG();
 593         }
 594
 595         nlh->nlmsg_len = inst->skb->tail - old_tail;
 596         return 0;
 597
 598 nla_put_failure:
 599         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 600         return -1;
 601 }
 602
 603 static struct nf_loginfo default_loginfo = {
 604         .type =         NF_LOG_TYPE_ULOG,
 605         .u = {
 606                 .ulog = {
 607                         .copy_len       = 0xffff,
 608                         .group          = 0,
 609                         .qthreshold     = 1,
 610                 },
 611         },
 612 };
 613
 614 /* log handler for internal netfilter logging api */
 615 void
 616 nfulnl_log_packet(struct net *net,
 617                   u_int8_t pf,
 618                   unsigned int hooknum,
 619                   const struct sk_buff *skb,
 620                   const struct net_device *in,
 621                   const struct net_device *out,
 622                   const struct nf_loginfo *li_user,
 623                   const char *prefix)
 624 {
 625         size_t size;
 626         unsigned int data_len;
 627         struct nfulnl_instance *inst;
 628         const struct nf_loginfo *li;
 629         unsigned int qthreshold;
 630         unsigned int plen;
 631         struct nfnl_log_net *log = nfnl_log_pernet(net);
 632         const struct nfnl_ct_hook *nfnl_ct = NULL;
 633         struct nf_conn *ct = NULL;
 634         enum ip_conntrack_info uninitialized_var(ctinfo);
 635
 636         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 637                 li = li_user;
 638         else
 639                 li = &default_loginfo;
 640
 641         inst = instance_lookup_get(log, li->u.ulog.group);
 642         if (!inst)
 643                 return;
 644
 645         plen = 0;
 646         if (prefix)
 647                 plen = strlen(prefix) + 1;
 648
 649         /* FIXME: do we want to make the size calculation conditional based on
 650          * what is actually present?  way more branches and checks, but more
 651          * memory efficient... */
 652         size =    nlmsg_total_size(sizeof(struct nfgenmsg))
 653                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 654                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 655                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 656 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 657                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 658                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 659 #endif
 660                 + nla_total_size(sizeof(u_int32_t))     /* mark */
 661                 + nla_total_size(sizeof(u_int32_t))     /* uid */
 662                 + nla_total_size(sizeof(u_int32_t))     /* gid */
 663                 + nla_total_size(plen)                  /* prefix */
 664                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 665                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
 666                 + nla_total_size(sizeof(struct nfgenmsg));      /* NLMSG_DONE */
 667
 668         if (in && skb_mac_header_was_set(skb)) {
 669                 size +=   nla_total_size(skb->dev->hard_header_len)
 670                         + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 671                         + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 672         }
 673
 674         spin_lock_bh(&inst->lock);
 675
 676         if (inst->flags & NFULNL_CFG_F_SEQ)
 677                 size += nla_total_size(sizeof(u_int32_t));
 678         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 679                 size += nla_total_size(sizeof(u_int32_t));
 680         if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
 681                 nfnl_ct = rcu_dereference(nfnl_ct_hook);
 682                 if (nfnl_ct != NULL) {
 683                         ct = nfnl_ct->get_ct(skb, &ctinfo);
 684                         if (ct != NULL)
 685                                 size += nfnl_ct->build_size(ct);
 686                 }
 687         }
 688
 689         qthreshold = inst->qthreshold;
 690         /* per-rule qthreshold overrides per-instance */
 691         if (li->u.ulog.qthreshold)
 692                 if (qthreshold > li->u.ulog.qthreshold)
 693                         qthreshold = li->u.ulog.qthreshold;
 694
 695
 696         switch (inst->copy_mode) {
 697         case NFULNL_COPY_META:
 698         case NFULNL_COPY_NONE:
 699                 data_len = 0;
 700                 break;
 701
 702         case NFULNL_COPY_PACKET:
 703                 if (inst->copy_range > skb->len)
 704                         data_len = skb->len;
 705                 else
 706                         data_len = inst->copy_range;
 707
 708                 size += nla_total_size(data_len);
 709                 break;
 710
 711         case NFULNL_COPY_DISABLED:
 712         default:
 713                 goto unlock_and_release;
 714         }
 715
 716         if (inst->skb && size > skb_tailroom(inst->skb)) {
 717                 /* either the queue len is too high or we don't have
 718                  * enough room in the skb left. flush to userspace. */
 719                 __nfulnl_flush(inst);
 720         }
 721
 722         if (!inst->skb) {
 723                 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
 724                                              inst->nlbufsiz, size);
 725                 if (!inst->skb)
 726                         goto alloc_failure;
 727         }
 728
 729         inst->qlen++;
 730
 731         __build_packet_message(log, inst, skb, data_len, pf,
 732                                 hooknum, in, out, prefix, plen,
 733                                 nfnl_ct, ct, ctinfo);
 734
 735         if (inst->qlen >= qthreshold)
 736                 __nfulnl_flush(inst);
 737         /* timer_pending always called within inst->lock, so there
 738          * is no chance of a race here */
 739         else if (!timer_pending(&inst->timer)) {
 740                 instance_get(inst);
 741                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 742                 add_timer(&inst->timer);
 743         }
 744
 745 unlock_and_release:
 746         spin_unlock_bh(&inst->lock);
 747         instance_put(inst);
 748         return;
 749
 750 alloc_failure:
 751         /* FIXME: statistics */
 752         goto unlock_and_release;
 753 }
 754 EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 755
 756 static int
 757 nfulnl_rcv_nl_event(struct notifier_block *this,
 758                    unsigned long event, void *ptr)
 759 {
 760         struct netlink_notify *n = ptr;
 761         struct nfnl_log_net *log = nfnl_log_pernet(n->net);
 762
 763         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 764                 int i;
 765
 766                 /* destroy all instances for this portid */
 767                 spin_lock_bh(&log->instances_lock);
 768                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 769                         struct hlist_node *t2;
 770                         struct nfulnl_instance *inst;
 771                         struct hlist_head *head = &log->instance_table[i];
 772
 773                         hlist_for_each_entry_safe(inst, t2, head, hlist) {
 774                                 if (n->portid == inst->peer_portid)
 775                                         __instance_destroy(inst);
 776                         }
 777                 }
 778                 spin_unlock_bh(&log->instances_lock);
 779         }
 780         return NOTIFY_DONE;
 781 }
 782
 783 static struct notifier_block nfulnl_rtnl_notifier = {
 784         .notifier_call  = nfulnl_rcv_nl_event,
 785 };
 786
 787 static int nfulnl_recv_unsupp(struct net *net, struct sock *ctnl,
 788                               struct sk_buff *skb, const struct nlmsghdr *nlh,
 789                               const struct nlattr * const nfqa[])
 790 {
 791         return -ENOTSUPP;
 792 }
 793
 794 static struct nf_logger nfulnl_logger __read_mostly = {
 795         .name   = "nfnetlink_log",
 796         .type   = NF_LOG_TYPE_ULOG,
 797         .logfn  = &nfulnl_log_packet,
 798         .me     = THIS_MODULE,
 799 };
 800
 801 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 802         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 803         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 804         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 805         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 806         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 807         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 808 };
 809
 810 static int nfulnl_recv_config(struct net *net, struct sock *ctnl,
 811                               struct sk_buff *skb, const struct nlmsghdr *nlh,
 812                               const struct nlattr * const nfula[])
 813 {
 814         struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 815         u_int16_t group_num = ntohs(nfmsg->res_id);
 816         struct nfulnl_instance *inst;
 817         struct nfulnl_msg_config_cmd *cmd = NULL;
 818         struct nfnl_log_net *log = nfnl_log_pernet(net);
 819         int ret = 0;
 820         u16 flags = 0;
 821
 822         if (nfula[NFULA_CFG_CMD]) {
 823                 u_int8_t pf = nfmsg->nfgen_family;
 824                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
 825
 826                 /* Commands without queue context */
 827                 switch (cmd->command) {
 828                 case NFULNL_CFG_CMD_PF_BIND:
 829                         return nf_log_bind_pf(net, pf, &nfulnl_logger);
 830                 case NFULNL_CFG_CMD_PF_UNBIND:
 831                         nf_log_unbind_pf(net, pf);
 832                         return 0;
 833                 }
 834         }
 835
 836         inst = instance_lookup_get(log, group_num);
 837         if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
 838                 ret = -EPERM;
 839                 goto out_put;
 840         }
 841
 842         /* Check if we support these flags in first place, dependencies should
 843          * be there too not to break atomicity.
 844          */
 845         if (nfula[NFULA_CFG_FLAGS]) {
 846                 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
 847
 848                 if ((flags & NFULNL_CFG_F_CONNTRACK) &&
 849                     !rcu_access_pointer(nfnl_ct_hook)) {
 850 #ifdef CONFIG_MODULES
 851                         nfnl_unlock(NFNL_SUBSYS_ULOG);
 852                         request_module("ip_conntrack_netlink");
 853                         nfnl_lock(NFNL_SUBSYS_ULOG);
 854                         if (rcu_access_pointer(nfnl_ct_hook)) {
 855                                 ret = -EAGAIN;
 856                                 goto out_put;
 857                         }
 858 #endif
 859                         ret = -EOPNOTSUPP;
 860                         goto out_put;
 861                 }
 862         }
 863
 864         if (cmd != NULL) {
 865                 switch (cmd->command) {
 866                 case NFULNL_CFG_CMD_BIND:
 867                         if (inst) {
 868                                 ret = -EBUSY;
 869                                 goto out_put;
 870                         }
 871
 872                         inst = instance_create(net, group_num,
 873                                                NETLINK_CB(skb).portid,
 874                                                sk_user_ns(NETLINK_CB(skb).sk));
 875                         if (IS_ERR(inst)) {
 876                                 ret = PTR_ERR(inst);
 877                                 goto out;
 878                         }
 879                         break;
 880                 case NFULNL_CFG_CMD_UNBIND:
 881                         if (!inst) {
 882                                 ret = -ENODEV;
 883                                 goto out;
 884                         }
 885
 886                         instance_destroy(log, inst);
 887                         goto out_put;
 888                 default:
 889                         ret = -ENOTSUPP;
 890                         goto out_put;
 891                 }
 892         } else if (!inst) {
 893                 ret = -ENODEV;
 894                 goto out;
 895         }
 896
 897         if (nfula[NFULA_CFG_MODE]) {
 898                 struct nfulnl_msg_config_mode *params =
 899                         nla_data(nfula[NFULA_CFG_MODE]);
 900
 901                 nfulnl_set_mode(inst, params->copy_mode,
 902                                 ntohl(params->copy_range));
 903         }
 904
 905         if (nfula[NFULA_CFG_TIMEOUT]) {
 906                 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 907
 908                 nfulnl_set_timeout(inst, ntohl(timeout));
 909         }
 910
 911         if (nfula[NFULA_CFG_NLBUFSIZ]) {
 912                 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 913
 914                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 915         }
 916
 917         if (nfula[NFULA_CFG_QTHRESH]) {
 918                 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 919
 920                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 921         }
 922
 923         if (nfula[NFULA_CFG_FLAGS])
 924                 nfulnl_set_flags(inst, flags);
 925
 926 out_put:
 927         instance_put(inst);
 928 out:
 929         return ret;
 930 }
 931
 932 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 933         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 934                                     .attr_count = NFULA_MAX, },
 935         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 936                                     .attr_count = NFULA_CFG_MAX,
 937                                     .policy = nfula_cfg_policy },
 938 };
 939
 940 static const struct nfnetlink_subsystem nfulnl_subsys = {
 941         .name           = "log",
 942         .subsys_id      = NFNL_SUBSYS_ULOG,
 943         .cb_count       = NFULNL_MSG_MAX,
 944         .cb             = nfulnl_cb,
 945 };
 946
 947 #ifdef CONFIG_PROC_FS
 948 struct iter_state {
 949         struct seq_net_private p;
 950         unsigned int bucket;
 951 };
 952
 953 static struct hlist_node *get_first(struct net *net, struct iter_state *st)
 954 {
 955         struct nfnl_log_net *log;
 956         if (!st)
 957                 return NULL;
 958
 959         log = nfnl_log_pernet(net);
 960
 961         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 962                 struct hlist_head *head = &log->instance_table[st->bucket];
 963
 964                 if (!hlist_empty(head))
 965                         return rcu_dereference_bh(hlist_first_rcu(head));
 966         }
 967         return NULL;
 968 }
 969
 970 static struct hlist_node *get_next(struct net *net, struct iter_state *st,
 971                                    struct hlist_node *h)
 972 {
 973         h = rcu_dereference_bh(hlist_next_rcu(h));
 974         while (!h) {
 975                 struct nfnl_log_net *log;
 976                 struct hlist_head *head;
 977
 978                 if (++st->bucket >= INSTANCE_BUCKETS)
 979                         return NULL;
 980
 981                 log = nfnl_log_pernet(net);
 982                 head = &log->instance_table[st->bucket];
 983                 h = rcu_dereference_bh(hlist_first_rcu(head));
 984         }
 985         return h;
 986 }
 987
 988 static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
 989                                   loff_t pos)
 990 {
 991         struct hlist_node *head;
 992         head = get_first(net, st);
 993
 994         if (head)
 995                 while (pos && (head = get_next(net, st, head)))
 996                         pos--;
 997         return pos ? NULL : head;
 998 }
 999
1000 static void *seq_start(struct seq_file *s, loff_t *pos)
1001         __acquires(rcu_bh)
1002 {
1003         rcu_read_lock_bh();
1004         return get_idx(seq_file_net(s), s->private, *pos);
1005 }
1006
1007 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
1008 {
1009         (*pos)++;
1010         return get_next(seq_file_net(s), s->private, v);
1011 }
1012
1013 static void seq_stop(struct seq_file *s, void *v)
1014         __releases(rcu_bh)
1015 {
1016         rcu_read_unlock_bh();
1017 }
1018
1019 static int seq_show(struct seq_file *s, void *v)
1020 {
1021         const struct nfulnl_instance *inst = v;
1022
1023         seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1024                    inst->group_num,
1025                    inst->peer_portid, inst->qlen,
1026                    inst->copy_mode, inst->copy_range,
1027                    inst->flushtimeout, atomic_read(&inst->use));
1028
1029         return 0;
1030 }
1031
1032 static const struct seq_operations nful_seq_ops = {
1033         .start  = seq_start,
1034         .next   = seq_next,
1035         .stop   = seq_stop,
1036         .show   = seq_show,
1037 };
1038
1039 static int nful_open(struct inode *inode, struct file *file)
1040 {
1041         return seq_open_net(inode, file, &nful_seq_ops,
1042                             sizeof(struct iter_state));
1043 }
1044
1045 static const struct file_operations nful_file_ops = {
1046         .owner   = THIS_MODULE,
1047         .open    = nful_open,
1048         .read    = seq_read,
1049         .llseek  = seq_lseek,
1050         .release = seq_release_net,
1051 };
1052
1053 #endif /* PROC_FS */
1054
1055 static int __net_init nfnl_log_net_init(struct net *net)
1056 {
1057         unsigned int i;
1058         struct nfnl_log_net *log = nfnl_log_pernet(net);
1059 #ifdef CONFIG_PROC_FS
1060         struct proc_dir_entry *proc;
1061         kuid_t root_uid;
1062         kgid_t root_gid;
1063 #endif
1064
1065         for (i = 0; i < INSTANCE_BUCKETS; i++)
1066                 INIT_HLIST_HEAD(&log->instance_table[i]);
1067         spin_lock_init(&log->instances_lock);
1068
1069 #ifdef CONFIG_PROC_FS
1070         proc = proc_create("nfnetlink_log", 0440,
1071                            net->nf.proc_netfilter, &nful_file_ops);
1072         if (!proc)
1073                 return -ENOMEM;
1074
1075         root_uid = make_kuid(net->user_ns, 0);
1076         root_gid = make_kgid(net->user_ns, 0);
1077         if (uid_valid(root_uid) && gid_valid(root_gid))
1078                 proc_set_user(proc, root_uid, root_gid);
1079 #endif
1080         return 0;
1081 }
1082
1083 static void __net_exit nfnl_log_net_exit(struct net *net)
1084 {
1085 #ifdef CONFIG_PROC_FS
1086         remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1087 #endif
1088         nf_log_unset(net, &nfulnl_logger);
1089 }
1090
1091 static struct pernet_operations nfnl_log_net_ops = {
1092         .init   = nfnl_log_net_init,
1093         .exit   = nfnl_log_net_exit,
1094         .id     = &nfnl_log_net_id,
1095         .size   = sizeof(struct nfnl_log_net),
1096 };
1097
1098 static int __init nfnetlink_log_init(void)
1099 {
1100         int status;
1101
1102         status = register_pernet_subsys(&nfnl_log_net_ops);
1103         if (status < 0) {
1104                 pr_err("failed to register pernet ops\n");
1105                 goto out;
1106         }
1107
1108         netlink_register_notifier(&nfulnl_rtnl_notifier);
1109         status = nfnetlink_subsys_register(&nfulnl_subsys);
1110         if (status < 0) {
1111                 pr_err("failed to create netlink socket\n");
1112                 goto cleanup_netlink_notifier;
1113         }
1114
1115         status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1116         if (status < 0) {
1117                 pr_err("failed to register logger\n");
1118                 goto cleanup_subsys;
1119         }
1120
1121         return status;
1122
1123 cleanup_subsys:
1124         nfnetlink_subsys_unregister(&nfulnl_subsys);
1125 cleanup_netlink_notifier:
1126         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1127         unregister_pernet_subsys(&nfnl_log_net_ops);
1128 out:
1129         return status;
1130 }
1131
1132 static void __exit nfnetlink_log_fini(void)
1133 {
1134         nf_log_unregister(&nfulnl_logger);
1135         nfnetlink_subsys_unregister(&nfulnl_subsys);
1136         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1137         unregister_pernet_subsys(&nfnl_log_net_ops);
1138 }
1139
1140 MODULE_DESCRIPTION("netfilter userspace logging");
1141 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1142 MODULE_LICENSE("GPL");
1143 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1144 MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1145 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1146 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1147
1148 module_init(nfnetlink_log_init);
1149 module_exit(nfnetlink_log_fini);