net/netfilter/nfnetlink_log.c

   1 /*
   2  * This is a module which is used for logging packets to userspace via
   3  * nfetlink.
   4  *
   5  * (C) 2005 by Harald Welte <laforge@netfilter.org>
   6  * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
   7  *
   8  * Based on the old ipv4-only ipt_ULOG.c:
   9  * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18 #include <linux/module.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/if_arp.h>
  21 #include <linux/init.h>
  22 #include <linux/ip.h>
  23 #include <linux/ipv6.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/netfilter.h>
  26 #include <linux/netfilter_bridge.h>
  27 #include <net/netlink.h>
  28 #include <linux/netfilter/nfnetlink.h>
  29 #include <linux/netfilter/nfnetlink_log.h>
  30 #include <linux/netfilter/nf_conntrack_common.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/sysctl.h>
  33 #include <linux/proc_fs.h>
  34 #include <linux/security.h>
  35 #include <linux/list.h>
  36 #include <linux/slab.h>
  37 #include <net/sock.h>
  38 #include <net/netfilter/nf_log.h>
  39 #include <net/netns/generic.h>
  40 #include <net/netfilter/nfnetlink_log.h>
  41
  42 #include <linux/atomic.h>
  43
  44 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
  45 #include "../bridge/br_private.h"
  46 #endif
  47
  48 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  49 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  50 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  51 /* max packet size is limited by 16-bit struct nfattr nfa_len field */
  52 #define NFULNL_COPY_RANGE_MAX   (0xFFFF - NLA_HDRLEN)
  53
  54 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  55                                      printk(x, ## args); } while (0);
  56
  57 struct nfulnl_instance {
  58         struct hlist_node hlist;        /* global list of instances */
  59         spinlock_t lock;
  60         atomic_t use;                   /* use count */
  61
  62         unsigned int qlen;              /* number of nlmsgs in skb */
  63         struct sk_buff *skb;            /* pre-allocatd skb */
  64         struct timer_list timer;
  65         struct net *net;
  66         struct user_namespace *peer_user_ns;    /* User namespace of the peer process */
  67         u32 peer_portid;                /* PORTID of the peer process */
  68
  69         /* configurable parameters */
  70         unsigned int flushtimeout;      /* timeout until queue flush */
  71         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  72         unsigned int qthreshold;        /* threshold of the queue */
  73         u_int32_t copy_range;
  74         u_int32_t seq;                  /* instance-local sequential counter */
  75         u_int16_t group_num;            /* number of this queue */
  76         u_int16_t flags;
  77         u_int8_t copy_mode;
  78         struct rcu_head rcu;
  79 };
  80
  81 #define INSTANCE_BUCKETS        16
  82
  83 static int nfnl_log_net_id __read_mostly;
  84
  85 struct nfnl_log_net {
  86         spinlock_t instances_lock;
  87         struct hlist_head instance_table[INSTANCE_BUCKETS];
  88         atomic_t global_seq;
  89 };
  90
  91 static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
  92 {
  93         return net_generic(net, nfnl_log_net_id);
  94 }
  95
  96 static inline u_int8_t instance_hashfn(u_int16_t group_num)
  97 {
  98         return ((group_num & 0xff) % INSTANCE_BUCKETS);
  99 }
 100
 101 static struct nfulnl_instance *
 102 __instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
 103 {
 104         struct hlist_head *head;
 105         struct nfulnl_instance *inst;
 106
 107         head = &log->instance_table[instance_hashfn(group_num)];
 108         hlist_for_each_entry_rcu(inst, head, hlist) {
 109                 if (inst->group_num == group_num)
 110                         return inst;
 111         }
 112         return NULL;
 113 }
 114
 115 static inline void
 116 instance_get(struct nfulnl_instance *inst)
 117 {
 118         atomic_inc(&inst->use);
 119 }
 120
 121 static struct nfulnl_instance *
 122 instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
 123 {
 124         struct nfulnl_instance *inst;
 125
 126         rcu_read_lock_bh();
 127         inst = __instance_lookup(log, group_num);
 128         if (inst && !atomic_inc_not_zero(&inst->use))
 129                 inst = NULL;
 130         rcu_read_unlock_bh();
 131
 132         return inst;
 133 }
 134
 135 static void nfulnl_instance_free_rcu(struct rcu_head *head)
 136 {
 137         struct nfulnl_instance *inst =
 138                 container_of(head, struct nfulnl_instance, rcu);
 139
 140         put_net(inst->net);
 141         kfree(inst);
 142         module_put(THIS_MODULE);
 143 }
 144
 145 static void
 146 instance_put(struct nfulnl_instance *inst)
 147 {
 148         if (inst && atomic_dec_and_test(&inst->use))
 149                 call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
 150 }
 151
 152 static void nfulnl_timer(unsigned long data);
 153
 154 static struct nfulnl_instance *
 155 instance_create(struct net *net, u_int16_t group_num,
 156                 u32 portid, struct user_namespace *user_ns)
 157 {
 158         struct nfulnl_instance *inst;
 159         struct nfnl_log_net *log = nfnl_log_pernet(net);
 160         int err;
 161
 162         spin_lock_bh(&log->instances_lock);
 163         if (__instance_lookup(log, group_num)) {
 164                 err = -EEXIST;
 165                 goto out_unlock;
 166         }
 167
 168         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 169         if (!inst) {
 170                 err = -ENOMEM;
 171                 goto out_unlock;
 172         }
 173
 174         if (!try_module_get(THIS_MODULE)) {
 175                 kfree(inst);
 176                 err = -EAGAIN;
 177                 goto out_unlock;
 178         }
 179
 180         INIT_HLIST_NODE(&inst->hlist);
 181         spin_lock_init(&inst->lock);
 182         /* needs to be two, since we _put() after creation */
 183         atomic_set(&inst->use, 2);
 184
 185         setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
 186
 187         inst->net = get_net(net);
 188         inst->peer_user_ns = user_ns;
 189         inst->peer_portid = portid;
 190         inst->group_num = group_num;
 191
 192         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 193         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 194         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 195         inst->copy_mode         = NFULNL_COPY_PACKET;
 196         inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 197
 198         hlist_add_head_rcu(&inst->hlist,
 199                        &log->instance_table[instance_hashfn(group_num)]);
 200
 201
 202         spin_unlock_bh(&log->instances_lock);
 203
 204         return inst;
 205
 206 out_unlock:
 207         spin_unlock_bh(&log->instances_lock);
 208         return ERR_PTR(err);
 209 }
 210
 211 static void __nfulnl_flush(struct nfulnl_instance *inst);
 212
 213 /* called with BH disabled */
 214 static void
 215 __instance_destroy(struct nfulnl_instance *inst)
 216 {
 217         /* first pull it out of the global list */
 218         hlist_del_rcu(&inst->hlist);
 219
 220         /* then flush all pending packets from skb */
 221
 222         spin_lock(&inst->lock);
 223
 224         /* lockless readers wont be able to use us */
 225         inst->copy_mode = NFULNL_COPY_DISABLED;
 226
 227         if (inst->skb)
 228                 __nfulnl_flush(inst);
 229         spin_unlock(&inst->lock);
 230
 231         /* and finally put the refcount */
 232         instance_put(inst);
 233 }
 234
 235 static inline void
 236 instance_destroy(struct nfnl_log_net *log,
 237                  struct nfulnl_instance *inst)
 238 {
 239         spin_lock_bh(&log->instances_lock);
 240         __instance_destroy(inst);
 241         spin_unlock_bh(&log->instances_lock);
 242 }
 243
 244 static int
 245 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 246                   unsigned int range)
 247 {
 248         int status = 0;
 249
 250         spin_lock_bh(&inst->lock);
 251
 252         switch (mode) {
 253         case NFULNL_COPY_NONE:
 254         case NFULNL_COPY_META:
 255                 inst->copy_mode = mode;
 256                 inst->copy_range = 0;
 257                 break;
 258
 259         case NFULNL_COPY_PACKET:
 260                 inst->copy_mode = mode;
 261                 if (range == 0)
 262                         range = NFULNL_COPY_RANGE_MAX;
 263                 inst->copy_range = min_t(unsigned int,
 264                                          range, NFULNL_COPY_RANGE_MAX);
 265                 break;
 266
 267         default:
 268                 status = -EINVAL;
 269                 break;
 270         }
 271
 272         spin_unlock_bh(&inst->lock);
 273
 274         return status;
 275 }
 276
 277 static int
 278 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 279 {
 280         int status;
 281
 282         spin_lock_bh(&inst->lock);
 283         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 284                 status = -ERANGE;
 285         else if (nlbufsiz > 131072)
 286                 status = -ERANGE;
 287         else {
 288                 inst->nlbufsiz = nlbufsiz;
 289                 status = 0;
 290         }
 291         spin_unlock_bh(&inst->lock);
 292
 293         return status;
 294 }
 295
 296 static void
 297 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 298 {
 299         spin_lock_bh(&inst->lock);
 300         inst->flushtimeout = timeout;
 301         spin_unlock_bh(&inst->lock);
 302 }
 303
 304 static void
 305 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 306 {
 307         spin_lock_bh(&inst->lock);
 308         inst->qthreshold = qthresh;
 309         spin_unlock_bh(&inst->lock);
 310 }
 311
 312 static int
 313 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 314 {
 315         spin_lock_bh(&inst->lock);
 316         inst->flags = flags;
 317         spin_unlock_bh(&inst->lock);
 318
 319         return 0;
 320 }
 321
 322 static struct sk_buff *
 323 nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
 324                  unsigned int pkt_size)
 325 {
 326         struct sk_buff *skb;
 327         unsigned int n;
 328
 329         /* alloc skb which should be big enough for a whole multipart
 330          * message.  WARNING: has to be <= 128k due to slab restrictions */
 331
 332         n = max(inst_size, pkt_size);
 333         skb = alloc_skb(n, GFP_ATOMIC);
 334         if (!skb) {
 335                 if (n > pkt_size) {
 336                         /* try to allocate only as much as we need for current
 337                          * packet */
 338
 339                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
 340                 }
 341         }
 342
 343         return skb;
 344 }
 345
 346 static void
 347 __nfulnl_send(struct nfulnl_instance *inst)
 348 {
 349         if (inst->qlen > 1) {
 350                 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 351                                                  NLMSG_DONE,
 352                                                  sizeof(struct nfgenmsg),
 353                                                  0);
 354                 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
 355                               inst->skb->len, skb_tailroom(inst->skb))) {
 356                         kfree_skb(inst->skb);
 357                         goto out;
 358                 }
 359         }
 360         nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
 361                           MSG_DONTWAIT);
 362 out:
 363         inst->qlen = 0;
 364         inst->skb = NULL;
 365 }
 366
 367 static void
 368 __nfulnl_flush(struct nfulnl_instance *inst)
 369 {
 370         /* timer holds a reference */
 371         if (del_timer(&inst->timer))
 372                 instance_put(inst);
 373         if (inst->skb)
 374                 __nfulnl_send(inst);
 375 }
 376
 377 static void
 378 nfulnl_timer(unsigned long data)
 379 {
 380         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 381
 382         spin_lock_bh(&inst->lock);
 383         if (inst->skb)
 384                 __nfulnl_send(inst);
 385         spin_unlock_bh(&inst->lock);
 386         instance_put(inst);
 387 }
 388
 389 /* This is an inline function, we don't really care about a long
 390  * list of arguments */
 391 static inline int
 392 __build_packet_message(struct nfnl_log_net *log,
 393                         struct nfulnl_instance *inst,
 394                         const struct sk_buff *skb,
 395                         unsigned int data_len,
 396                         u_int8_t pf,
 397                         unsigned int hooknum,
 398                         const struct net_device *indev,
 399                         const struct net_device *outdev,
 400                         const char *prefix, unsigned int plen,
 401                         const struct nfnl_ct_hook *nfnl_ct,
 402                         struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 403 {
 404         struct nfulnl_msg_packet_hdr pmsg;
 405         struct nlmsghdr *nlh;
 406         struct nfgenmsg *nfmsg;
 407         sk_buff_data_t old_tail = inst->skb->tail;
 408         struct sock *sk;
 409         const unsigned char *hwhdrp;
 410
 411         nlh = nlmsg_put(inst->skb, 0, 0,
 412                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 413                         sizeof(struct nfgenmsg), 0);
 414         if (!nlh)
 415                 return -1;
 416         nfmsg = nlmsg_data(nlh);
 417         nfmsg->nfgen_family = pf;
 418         nfmsg->version = NFNETLINK_V0;
 419         nfmsg->res_id = htons(inst->group_num);
 420
 421         memset(&pmsg, 0, sizeof(pmsg));
 422         pmsg.hw_protocol        = skb->protocol;
 423         pmsg.hook               = hooknum;
 424
 425         if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
 426                 goto nla_put_failure;
 427
 428         if (prefix &&
 429             nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
 430                 goto nla_put_failure;
 431
 432         if (indev) {
 433 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 434                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 435                                  htonl(indev->ifindex)))
 436                         goto nla_put_failure;
 437 #else
 438                 if (pf == PF_BRIDGE) {
 439                         /* Case 1: outdev is physical input device, we need to
 440                          * look for bridge group (when called from
 441                          * netfilter_bridge) */
 442                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 443                                          htonl(indev->ifindex)) ||
 444                         /* this is the bridge group "brX" */
 445                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 446                             nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 447                                          htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 448                                 goto nla_put_failure;
 449                 } else {
 450                         struct net_device *physindev;
 451
 452                         /* Case 2: indev is bridge group, we need to look for
 453                          * physical device (when called from ipv4) */
 454                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 455                                          htonl(indev->ifindex)))
 456                                 goto nla_put_failure;
 457
 458                         physindev = nf_bridge_get_physindev(skb);
 459                         if (physindev &&
 460                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 461                                          htonl(physindev->ifindex)))
 462                                 goto nla_put_failure;
 463                 }
 464 #endif
 465         }
 466
 467         if (outdev) {
 468 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 469                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 470                                  htonl(outdev->ifindex)))
 471                         goto nla_put_failure;
 472 #else
 473                 if (pf == PF_BRIDGE) {
 474                         /* Case 1: outdev is physical output device, we need to
 475                          * look for bridge group (when called from
 476                          * netfilter_bridge) */
 477                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 478                                          htonl(outdev->ifindex)) ||
 479                         /* this is the bridge group "brX" */
 480                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 481                             nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 482                                          htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 483                                 goto nla_put_failure;
 484                 } else {
 485                         struct net_device *physoutdev;
 486
 487                         /* Case 2: indev is a bridge group, we need to look
 488                          * for physical device (when called from ipv4) */
 489                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 490                                          htonl(outdev->ifindex)))
 491                                 goto nla_put_failure;
 492
 493                         physoutdev = nf_bridge_get_physoutdev(skb);
 494                         if (physoutdev &&
 495                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 496                                          htonl(physoutdev->ifindex)))
 497                                 goto nla_put_failure;
 498                 }
 499 #endif
 500         }
 501
 502         if (skb->mark &&
 503             nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
 504                 goto nla_put_failure;
 505
 506         if (indev && skb->dev &&
 507             skb->mac_header != skb->network_header) {
 508                 struct nfulnl_msg_packet_hw phw;
 509                 int len;
 510
 511                 memset(&phw, 0, sizeof(phw));
 512                 len = dev_parse_header(skb, phw.hw_addr);
 513                 if (len > 0) {
 514                         phw.hw_addrlen = htons(len);
 515                         if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 516                                 goto nla_put_failure;
 517                 }
 518         }
 519
 520         if (indev && skb_mac_header_was_set(skb)) {
 521                 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 522                     nla_put_be16(inst->skb, NFULA_HWLEN,
 523                                  htons(skb->dev->hard_header_len)))
 524                         goto nla_put_failure;
 525
 526                 hwhdrp = skb_mac_header(skb);
 527
 528                 if (skb->dev->type == ARPHRD_SIT)
 529                         hwhdrp -= ETH_HLEN;
 530
 531                 if (hwhdrp >= skb->head &&
 532                     nla_put(inst->skb, NFULA_HWHEADER,
 533                             skb->dev->hard_header_len, hwhdrp))
 534                         goto nla_put_failure;
 535         }
 536
 537         if (skb->tstamp.tv64) {
 538                 struct nfulnl_msg_packet_timestamp ts;
 539                 struct timespec64 kts = ktime_to_timespec64(skb->tstamp);
 540                 ts.sec = cpu_to_be64(kts.tv_sec);
 541                 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
 542
 543                 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 544                         goto nla_put_failure;
 545         }
 546
 547         /* UID */
 548         sk = skb->sk;
 549         if (sk && sk_fullsock(sk)) {
 550                 read_lock_bh(&sk->sk_callback_lock);
 551                 if (sk->sk_socket && sk->sk_socket->file) {
 552                         struct file *file = sk->sk_socket->file;
 553                         const struct cred *cred = file->f_cred;
 554                         struct user_namespace *user_ns = inst->peer_user_ns;
 555                         __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
 556                         __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
 557                         read_unlock_bh(&sk->sk_callback_lock);
 558                         if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 559                             nla_put_be32(inst->skb, NFULA_GID, gid))
 560                                 goto nla_put_failure;
 561                 } else
 562                         read_unlock_bh(&sk->sk_callback_lock);
 563         }
 564
 565         /* local sequence number */
 566         if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 567             nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 568                 goto nla_put_failure;
 569
 570         /* global sequence number */
 571         if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 572             nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 573                          htonl(atomic_inc_return(&log->global_seq))))
 574                 goto nla_put_failure;
 575
 576         if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
 577                                  NFULA_CT, NFULA_CT_INFO) < 0)
 578                 goto nla_put_failure;
 579
 580         if (data_len) {
 581                 struct nlattr *nla;
 582                 int size = nla_attr_size(data_len);
 583
 584                 if (skb_tailroom(inst->skb) < nla_total_size(data_len))
 585                         goto nla_put_failure;
 586
 587                 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
 588                 nla->nla_type = NFULA_PAYLOAD;
 589                 nla->nla_len = size;
 590
 591                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 592                         BUG();
 593         }
 594
 595         nlh->nlmsg_len = inst->skb->tail - old_tail;
 596         return 0;
 597
 598 nla_put_failure:
 599         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 600         return -1;
 601 }
 602
 603 static struct nf_loginfo default_loginfo = {
 604         .type =         NF_LOG_TYPE_ULOG,
 605         .u = {
 606                 .ulog = {
 607                         .copy_len       = 0xffff,
 608                         .group          = 0,
 609                         .qthreshold     = 1,
 610                 },
 611         },
 612 };
 613
 614 /* log handler for internal netfilter logging api */
 615 void
 616 nfulnl_log_packet(struct net *net,
 617                   u_int8_t pf,
 618                   unsigned int hooknum,
 619                   const struct sk_buff *skb,
 620                   const struct net_device *in,
 621                   const struct net_device *out,
 622                   const struct nf_loginfo *li_user,
 623                   const char *prefix)
 624 {
 625         size_t size;
 626         unsigned int data_len;
 627         struct nfulnl_instance *inst;
 628         const struct nf_loginfo *li;
 629         unsigned int qthreshold;
 630         unsigned int plen;
 631         struct nfnl_log_net *log = nfnl_log_pernet(net);
 632         const struct nfnl_ct_hook *nfnl_ct = NULL;
 633         struct nf_conn *ct = NULL;
 634         enum ip_conntrack_info uninitialized_var(ctinfo);
 635
 636         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 637                 li = li_user;
 638         else
 639                 li = &default_loginfo;
 640
 641         inst = instance_lookup_get(log, li->u.ulog.group);
 642         if (!inst)
 643                 return;
 644
 645         plen = 0;
 646         if (prefix)
 647                 plen = strlen(prefix) + 1;
 648
 649         /* FIXME: do we want to make the size calculation conditional based on
 650          * what is actually present?  way more branches and checks, but more
 651          * memory efficient... */
 652         size =    nlmsg_total_size(sizeof(struct nfgenmsg))
 653                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 654                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 655                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 656 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 657                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 658                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 659 #endif
 660                 + nla_total_size(sizeof(u_int32_t))     /* mark */
 661                 + nla_total_size(sizeof(u_int32_t))     /* uid */
 662                 + nla_total_size(sizeof(u_int32_t))     /* gid */
 663                 + nla_total_size(plen)                  /* prefix */
 664                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 665                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
 666                 + nla_total_size(sizeof(struct nfgenmsg));      /* NLMSG_DONE */
 667
 668         if (in && skb_mac_header_was_set(skb)) {
 669                 size +=   nla_total_size(skb->dev->hard_header_len)
 670                         + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 671                         + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 672         }
 673
 674         spin_lock_bh(&inst->lock);
 675
 676         if (inst->flags & NFULNL_CFG_F_SEQ)
 677                 size += nla_total_size(sizeof(u_int32_t));
 678         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 679                 size += nla_total_size(sizeof(u_int32_t));
 680         if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
 681                 nfnl_ct = rcu_dereference(nfnl_ct_hook);
 682                 if (nfnl_ct != NULL) {
 683                         ct = nfnl_ct->get_ct(skb, &ctinfo);
 684                         if (ct != NULL)
 685                                 size += nfnl_ct->build_size(ct);
 686                 }
 687         }
 688
 689         qthreshold = inst->qthreshold;
 690         /* per-rule qthreshold overrides per-instance */
 691         if (li->u.ulog.qthreshold)
 692                 if (qthreshold > li->u.ulog.qthreshold)
 693                         qthreshold = li->u.ulog.qthreshold;
 694
 695
 696         switch (inst->copy_mode) {
 697         case NFULNL_COPY_META:
 698         case NFULNL_COPY_NONE:
 699                 data_len = 0;
 700                 break;
 701
 702         case NFULNL_COPY_PACKET:
 703                 data_len = inst->copy_range;
 704                 if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) &&
 705                     (li->u.ulog.copy_len < data_len))
 706                         data_len = li->u.ulog.copy_len;
 707
 708                 if (data_len > skb->len)
 709                         data_len = skb->len;
 710
 711                 size += nla_total_size(data_len);
 712                 break;
 713
 714         case NFULNL_COPY_DISABLED:
 715         default:
 716                 goto unlock_and_release;
 717         }
 718
 719         if (inst->skb && size > skb_tailroom(inst->skb)) {
 720                 /* either the queue len is too high or we don't have
 721                  * enough room in the skb left. flush to userspace. */
 722                 __nfulnl_flush(inst);
 723         }
 724
 725         if (!inst->skb) {
 726                 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
 727                                              inst->nlbufsiz, size);
 728                 if (!inst->skb)
 729                         goto alloc_failure;
 730         }
 731
 732         inst->qlen++;
 733
 734         __build_packet_message(log, inst, skb, data_len, pf,
 735                                 hooknum, in, out, prefix, plen,
 736                                 nfnl_ct, ct, ctinfo);
 737
 738         if (inst->qlen >= qthreshold)
 739                 __nfulnl_flush(inst);
 740         /* timer_pending always called within inst->lock, so there
 741          * is no chance of a race here */
 742         else if (!timer_pending(&inst->timer)) {
 743                 instance_get(inst);
 744                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 745                 add_timer(&inst->timer);
 746         }
 747
 748 unlock_and_release:
 749         spin_unlock_bh(&inst->lock);
 750         instance_put(inst);
 751         return;
 752
 753 alloc_failure:
 754         /* FIXME: statistics */
 755         goto unlock_and_release;
 756 }
 757 EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 758
 759 static int
 760 nfulnl_rcv_nl_event(struct notifier_block *this,
 761                    unsigned long event, void *ptr)
 762 {
 763         struct netlink_notify *n = ptr;
 764         struct nfnl_log_net *log = nfnl_log_pernet(n->net);
 765
 766         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 767                 int i;
 768
 769                 /* destroy all instances for this portid */
 770                 spin_lock_bh(&log->instances_lock);
 771                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 772                         struct hlist_node *t2;
 773                         struct nfulnl_instance *inst;
 774                         struct hlist_head *head = &log->instance_table[i];
 775
 776                         hlist_for_each_entry_safe(inst, t2, head, hlist) {
 777                                 if (n->portid == inst->peer_portid)
 778                                         __instance_destroy(inst);
 779                         }
 780                 }
 781                 spin_unlock_bh(&log->instances_lock);
 782         }
 783         return NOTIFY_DONE;
 784 }
 785
 786 static struct notifier_block nfulnl_rtnl_notifier = {
 787         .notifier_call  = nfulnl_rcv_nl_event,
 788 };
 789
 790 static int nfulnl_recv_unsupp(struct net *net, struct sock *ctnl,
 791                               struct sk_buff *skb, const struct nlmsghdr *nlh,
 792                               const struct nlattr * const nfqa[])
 793 {
 794         return -ENOTSUPP;
 795 }
 796
 797 static struct nf_logger nfulnl_logger __read_mostly = {
 798         .name   = "nfnetlink_log",
 799         .type   = NF_LOG_TYPE_ULOG,
 800         .logfn  = &nfulnl_log_packet,
 801         .me     = THIS_MODULE,
 802 };
 803
 804 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 805         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 806         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 807         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 808         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 809         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 810         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 811 };
 812
 813 static int nfulnl_recv_config(struct net *net, struct sock *ctnl,
 814                               struct sk_buff *skb, const struct nlmsghdr *nlh,
 815                               const struct nlattr * const nfula[])
 816 {
 817         struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 818         u_int16_t group_num = ntohs(nfmsg->res_id);
 819         struct nfulnl_instance *inst;
 820         struct nfulnl_msg_config_cmd *cmd = NULL;
 821         struct nfnl_log_net *log = nfnl_log_pernet(net);
 822         int ret = 0;
 823         u16 flags = 0;
 824
 825         if (nfula[NFULA_CFG_CMD]) {
 826                 u_int8_t pf = nfmsg->nfgen_family;
 827                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
 828
 829                 /* Commands without queue context */
 830                 switch (cmd->command) {
 831                 case NFULNL_CFG_CMD_PF_BIND:
 832                         return nf_log_bind_pf(net, pf, &nfulnl_logger);
 833                 case NFULNL_CFG_CMD_PF_UNBIND:
 834                         nf_log_unbind_pf(net, pf);
 835                         return 0;
 836                 }
 837         }
 838
 839         inst = instance_lookup_get(log, group_num);
 840         if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
 841                 ret = -EPERM;
 842                 goto out_put;
 843         }
 844
 845         /* Check if we support these flags in first place, dependencies should
 846          * be there too not to break atomicity.
 847          */
 848         if (nfula[NFULA_CFG_FLAGS]) {
 849                 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
 850
 851                 if ((flags & NFULNL_CFG_F_CONNTRACK) &&
 852                     !rcu_access_pointer(nfnl_ct_hook)) {
 853 #ifdef CONFIG_MODULES
 854                         nfnl_unlock(NFNL_SUBSYS_ULOG);
 855                         request_module("ip_conntrack_netlink");
 856                         nfnl_lock(NFNL_SUBSYS_ULOG);
 857                         if (rcu_access_pointer(nfnl_ct_hook)) {
 858                                 ret = -EAGAIN;
 859                                 goto out_put;
 860                         }
 861 #endif
 862                         ret = -EOPNOTSUPP;
 863                         goto out_put;
 864                 }
 865         }
 866
 867         if (cmd != NULL) {
 868                 switch (cmd->command) {
 869                 case NFULNL_CFG_CMD_BIND:
 870                         if (inst) {
 871                                 ret = -EBUSY;
 872                                 goto out_put;
 873                         }
 874
 875                         inst = instance_create(net, group_num,
 876                                                NETLINK_CB(skb).portid,
 877                                                sk_user_ns(NETLINK_CB(skb).sk));
 878                         if (IS_ERR(inst)) {
 879                                 ret = PTR_ERR(inst);
 880                                 goto out;
 881                         }
 882                         break;
 883                 case NFULNL_CFG_CMD_UNBIND:
 884                         if (!inst) {
 885                                 ret = -ENODEV;
 886                                 goto out;
 887                         }
 888
 889                         instance_destroy(log, inst);
 890                         goto out_put;
 891                 default:
 892                         ret = -ENOTSUPP;
 893                         goto out_put;
 894                 }
 895         } else if (!inst) {
 896                 ret = -ENODEV;
 897                 goto out;
 898         }
 899
 900         if (nfula[NFULA_CFG_MODE]) {
 901                 struct nfulnl_msg_config_mode *params =
 902                         nla_data(nfula[NFULA_CFG_MODE]);
 903
 904                 nfulnl_set_mode(inst, params->copy_mode,
 905                                 ntohl(params->copy_range));
 906         }
 907
 908         if (nfula[NFULA_CFG_TIMEOUT]) {
 909                 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 910
 911                 nfulnl_set_timeout(inst, ntohl(timeout));
 912         }
 913
 914         if (nfula[NFULA_CFG_NLBUFSIZ]) {
 915                 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 916
 917                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 918         }
 919
 920         if (nfula[NFULA_CFG_QTHRESH]) {
 921                 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 922
 923                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 924         }
 925
 926         if (nfula[NFULA_CFG_FLAGS])
 927                 nfulnl_set_flags(inst, flags);
 928
 929 out_put:
 930         instance_put(inst);
 931 out:
 932         return ret;
 933 }
 934
 935 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 936         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 937                                     .attr_count = NFULA_MAX, },
 938         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 939                                     .attr_count = NFULA_CFG_MAX,
 940                                     .policy = nfula_cfg_policy },
 941 };
 942
 943 static const struct nfnetlink_subsystem nfulnl_subsys = {
 944         .name           = "log",
 945         .subsys_id      = NFNL_SUBSYS_ULOG,
 946         .cb_count       = NFULNL_MSG_MAX,
 947         .cb             = nfulnl_cb,
 948 };
 949
 950 #ifdef CONFIG_PROC_FS
 951 struct iter_state {
 952         struct seq_net_private p;
 953         unsigned int bucket;
 954 };
 955
 956 static struct hlist_node *get_first(struct net *net, struct iter_state *st)
 957 {
 958         struct nfnl_log_net *log;
 959         if (!st)
 960                 return NULL;
 961
 962         log = nfnl_log_pernet(net);
 963
 964         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 965                 struct hlist_head *head = &log->instance_table[st->bucket];
 966
 967                 if (!hlist_empty(head))
 968                         return rcu_dereference_bh(hlist_first_rcu(head));
 969         }
 970         return NULL;
 971 }
 972
 973 static struct hlist_node *get_next(struct net *net, struct iter_state *st,
 974                                    struct hlist_node *h)
 975 {
 976         h = rcu_dereference_bh(hlist_next_rcu(h));
 977         while (!h) {
 978                 struct nfnl_log_net *log;
 979                 struct hlist_head *head;
 980
 981                 if (++st->bucket >= INSTANCE_BUCKETS)
 982                         return NULL;
 983
 984                 log = nfnl_log_pernet(net);
 985                 head = &log->instance_table[st->bucket];
 986                 h = rcu_dereference_bh(hlist_first_rcu(head));
 987         }
 988         return h;
 989 }
 990
 991 static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
 992                                   loff_t pos)
 993 {
 994         struct hlist_node *head;
 995         head = get_first(net, st);
 996
 997         if (head)
 998                 while (pos && (head = get_next(net, st, head)))
 999                         pos--;
1000         return pos ? NULL : head;
1001 }
1002
1003 static void *seq_start(struct seq_file *s, loff_t *pos)
1004         __acquires(rcu_bh)
1005 {
1006         rcu_read_lock_bh();
1007         return get_idx(seq_file_net(s), s->private, *pos);
1008 }
1009
1010 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
1011 {
1012         (*pos)++;
1013         return get_next(seq_file_net(s), s->private, v);
1014 }
1015
1016 static void seq_stop(struct seq_file *s, void *v)
1017         __releases(rcu_bh)
1018 {
1019         rcu_read_unlock_bh();
1020 }
1021
1022 static int seq_show(struct seq_file *s, void *v)
1023 {
1024         const struct nfulnl_instance *inst = v;
1025
1026         seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1027                    inst->group_num,
1028                    inst->peer_portid, inst->qlen,
1029                    inst->copy_mode, inst->copy_range,
1030                    inst->flushtimeout, atomic_read(&inst->use));
1031
1032         return 0;
1033 }
1034
1035 static const struct seq_operations nful_seq_ops = {
1036         .start  = seq_start,
1037         .next   = seq_next,
1038         .stop   = seq_stop,
1039         .show   = seq_show,
1040 };
1041
1042 static int nful_open(struct inode *inode, struct file *file)
1043 {
1044         return seq_open_net(inode, file, &nful_seq_ops,
1045                             sizeof(struct iter_state));
1046 }
1047
1048 static const struct file_operations nful_file_ops = {
1049         .owner   = THIS_MODULE,
1050         .open    = nful_open,
1051         .read    = seq_read,
1052         .llseek  = seq_lseek,
1053         .release = seq_release_net,
1054 };
1055
1056 #endif /* PROC_FS */
1057
1058 static int __net_init nfnl_log_net_init(struct net *net)
1059 {
1060         unsigned int i;
1061         struct nfnl_log_net *log = nfnl_log_pernet(net);
1062 #ifdef CONFIG_PROC_FS
1063         struct proc_dir_entry *proc;
1064         kuid_t root_uid;
1065         kgid_t root_gid;
1066 #endif
1067
1068         for (i = 0; i < INSTANCE_BUCKETS; i++)
1069                 INIT_HLIST_HEAD(&log->instance_table[i]);
1070         spin_lock_init(&log->instances_lock);
1071
1072 #ifdef CONFIG_PROC_FS
1073         proc = proc_create("nfnetlink_log", 0440,
1074                            net->nf.proc_netfilter, &nful_file_ops);
1075         if (!proc)
1076                 return -ENOMEM;
1077
1078         root_uid = make_kuid(net->user_ns, 0);
1079         root_gid = make_kgid(net->user_ns, 0);
1080         if (uid_valid(root_uid) && gid_valid(root_gid))
1081                 proc_set_user(proc, root_uid, root_gid);
1082 #endif
1083         return 0;
1084 }
1085
1086 static void __net_exit nfnl_log_net_exit(struct net *net)
1087 {
1088 #ifdef CONFIG_PROC_FS
1089         remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1090 #endif
1091         nf_log_unset(net, &nfulnl_logger);
1092 }
1093
1094 static struct pernet_operations nfnl_log_net_ops = {
1095         .init   = nfnl_log_net_init,
1096         .exit   = nfnl_log_net_exit,
1097         .id     = &nfnl_log_net_id,
1098         .size   = sizeof(struct nfnl_log_net),
1099 };
1100
1101 static int __init nfnetlink_log_init(void)
1102 {
1103         int status;
1104
1105         status = register_pernet_subsys(&nfnl_log_net_ops);
1106         if (status < 0) {
1107                 pr_err("failed to register pernet ops\n");
1108                 goto out;
1109         }
1110
1111         netlink_register_notifier(&nfulnl_rtnl_notifier);
1112         status = nfnetlink_subsys_register(&nfulnl_subsys);
1113         if (status < 0) {
1114                 pr_err("failed to create netlink socket\n");
1115                 goto cleanup_netlink_notifier;
1116         }
1117
1118         status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1119         if (status < 0) {
1120                 pr_err("failed to register logger\n");
1121                 goto cleanup_subsys;
1122         }
1123
1124         return status;
1125
1126 cleanup_subsys:
1127         nfnetlink_subsys_unregister(&nfulnl_subsys);
1128 cleanup_netlink_notifier:
1129         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1130         unregister_pernet_subsys(&nfnl_log_net_ops);
1131 out:
1132         return status;
1133 }
1134
1135 static void __exit nfnetlink_log_fini(void)
1136 {
1137         nf_log_unregister(&nfulnl_logger);
1138         nfnetlink_subsys_unregister(&nfulnl_subsys);
1139         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1140         unregister_pernet_subsys(&nfnl_log_net_ops);
1141 }
1142
1143 MODULE_DESCRIPTION("netfilter userspace logging");
1144 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1145 MODULE_LICENSE("GPL");
1146 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1147 MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1148 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1149 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1150
1151 module_init(nfnetlink_log_init);
1152 module_exit(nfnetlink_log_fini);