kernel/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 int
 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         return 0;
 304 }
 305
 306 static int
 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         return 0;
 314 }
 315
 316 static int
 317 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 318 {
 319         spin_lock_bh(&inst->lock);
 320         inst->flags = flags;
 321         spin_unlock_bh(&inst->lock);
 322
 323         return 0;
 324 }
 325
 326 static struct sk_buff *
 327 nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
 328                  unsigned int pkt_size)
 329 {
 330         struct sk_buff *skb;
 331         unsigned int n;
 332
 333         /* alloc skb which should be big enough for a whole multipart
 334          * message.  WARNING: has to be <= 128k due to slab restrictions */
 335
 336         n = max(inst_size, pkt_size);
 337         skb = nfnetlink_alloc_skb(net, n, peer_portid, GFP_ATOMIC);
 338         if (!skb) {
 339                 if (n > pkt_size) {
 340                         /* try to allocate only as much as we need for current
 341                          * packet */
 342
 343                         skb = nfnetlink_alloc_skb(net, pkt_size,
 344                                                   peer_portid, GFP_ATOMIC);
 345                 }
 346         }
 347
 348         return skb;
 349 }
 350
 351 static void
 352 __nfulnl_send(struct nfulnl_instance *inst)
 353 {
 354         if (inst->qlen > 1) {
 355                 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 356                                                  NLMSG_DONE,
 357                                                  sizeof(struct nfgenmsg),
 358                                                  0);
 359                 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
 360                               inst->skb->len, skb_tailroom(inst->skb))) {
 361                         kfree_skb(inst->skb);
 362                         goto out;
 363                 }
 364         }
 365         nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
 366                           MSG_DONTWAIT);
 367 out:
 368         inst->qlen = 0;
 369         inst->skb = NULL;
 370 }
 371
 372 static void
 373 __nfulnl_flush(struct nfulnl_instance *inst)
 374 {
 375         /* timer holds a reference */
 376         if (del_timer(&inst->timer))
 377                 instance_put(inst);
 378         if (inst->skb)
 379                 __nfulnl_send(inst);
 380 }
 381
 382 static void
 383 nfulnl_timer(unsigned long data)
 384 {
 385         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 386
 387         spin_lock_bh(&inst->lock);
 388         if (inst->skb)
 389                 __nfulnl_send(inst);
 390         spin_unlock_bh(&inst->lock);
 391         instance_put(inst);
 392 }
 393
 394 /* This is an inline function, we don't really care about a long
 395  * list of arguments */
 396 static inline int
 397 __build_packet_message(struct nfnl_log_net *log,
 398                         struct nfulnl_instance *inst,
 399                         const struct sk_buff *skb,
 400                         unsigned int data_len,
 401                         u_int8_t pf,
 402                         unsigned int hooknum,
 403                         const struct net_device *indev,
 404                         const struct net_device *outdev,
 405                         const char *prefix, unsigned int plen,
 406                         const struct nfnl_ct_hook *nfnl_ct,
 407                         struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 408 {
 409         struct nfulnl_msg_packet_hdr pmsg;
 410         struct nlmsghdr *nlh;
 411         struct nfgenmsg *nfmsg;
 412         sk_buff_data_t old_tail = inst->skb->tail;
 413         struct sock *sk;
 414         const unsigned char *hwhdrp;
 415
 416         nlh = nlmsg_put(inst->skb, 0, 0,
 417                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 418                         sizeof(struct nfgenmsg), 0);
 419         if (!nlh)
 420                 return -1;
 421         nfmsg = nlmsg_data(nlh);
 422         nfmsg->nfgen_family = pf;
 423         nfmsg->version = NFNETLINK_V0;
 424         nfmsg->res_id = htons(inst->group_num);
 425
 426         memset(&pmsg, 0, sizeof(pmsg));
 427         pmsg.hw_protocol        = skb->protocol;
 428         pmsg.hook               = hooknum;
 429
 430         if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
 431                 goto nla_put_failure;
 432
 433         if (prefix &&
 434             nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
 435                 goto nla_put_failure;
 436
 437         if (indev) {
 438 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 439                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 440                                  htonl(indev->ifindex)))
 441                         goto nla_put_failure;
 442 #else
 443                 if (pf == PF_BRIDGE) {
 444                         /* Case 1: outdev is physical input device, we need to
 445                          * look for bridge group (when called from
 446                          * netfilter_bridge) */
 447                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 448                                          htonl(indev->ifindex)) ||
 449                         /* this is the bridge group "brX" */
 450                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 451                             nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 452                                          htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 453                                 goto nla_put_failure;
 454                 } else {
 455                         struct net_device *physindev;
 456
 457                         /* Case 2: indev is bridge group, we need to look for
 458                          * physical device (when called from ipv4) */
 459                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 460                                          htonl(indev->ifindex)))
 461                                 goto nla_put_failure;
 462
 463                         physindev = nf_bridge_get_physindev(skb);
 464                         if (physindev &&
 465                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 466                                          htonl(physindev->ifindex)))
 467                                 goto nla_put_failure;
 468                 }
 469 #endif
 470         }
 471
 472         if (outdev) {
 473 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 474                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 475                                  htonl(outdev->ifindex)))
 476                         goto nla_put_failure;
 477 #else
 478                 if (pf == PF_BRIDGE) {
 479                         /* Case 1: outdev is physical output device, we need to
 480                          * look for bridge group (when called from
 481                          * netfilter_bridge) */
 482                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 483                                          htonl(outdev->ifindex)) ||
 484                         /* this is the bridge group "brX" */
 485                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 486                             nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 487                                          htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 488                                 goto nla_put_failure;
 489                 } else {
 490                         struct net_device *physoutdev;
 491
 492                         /* Case 2: indev is a bridge group, we need to look
 493                          * for physical device (when called from ipv4) */
 494                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 495                                          htonl(outdev->ifindex)))
 496                                 goto nla_put_failure;
 497
 498                         physoutdev = nf_bridge_get_physoutdev(skb);
 499                         if (physoutdev &&
 500                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 501                                          htonl(physoutdev->ifindex)))
 502                                 goto nla_put_failure;
 503                 }
 504 #endif
 505         }
 506
 507         if (skb->mark &&
 508             nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
 509                 goto nla_put_failure;
 510
 511         if (indev && skb->dev &&
 512             skb->mac_header != skb->network_header) {
 513                 struct nfulnl_msg_packet_hw phw;
 514                 int len;
 515
 516                 memset(&phw, 0, sizeof(phw));
 517                 len = dev_parse_header(skb, phw.hw_addr);
 518                 if (len > 0) {
 519                         phw.hw_addrlen = htons(len);
 520                         if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 521                                 goto nla_put_failure;
 522                 }
 523         }
 524
 525         if (indev && skb_mac_header_was_set(skb)) {
 526                 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 527                     nla_put_be16(inst->skb, NFULA_HWLEN,
 528                                  htons(skb->dev->hard_header_len)))
 529                         goto nla_put_failure;
 530
 531                 hwhdrp = skb_mac_header(skb);
 532
 533                 if (skb->dev->type == ARPHRD_SIT)
 534                         hwhdrp -= ETH_HLEN;
 535
 536                 if (hwhdrp >= skb->head &&
 537                     nla_put(inst->skb, NFULA_HWHEADER,
 538                             skb->dev->hard_header_len, hwhdrp))
 539                         goto nla_put_failure;
 540         }
 541
 542         if (skb->tstamp.tv64) {
 543                 struct nfulnl_msg_packet_timestamp ts;
 544                 struct timespec64 kts = ktime_to_timespec64(skb->tstamp);
 545                 ts.sec = cpu_to_be64(kts.tv_sec);
 546                 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
 547
 548                 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 549                         goto nla_put_failure;
 550         }
 551
 552         /* UID */
 553         sk = skb->sk;
 554         if (sk && sk_fullsock(sk)) {
 555                 read_lock_bh(&sk->sk_callback_lock);
 556                 if (sk->sk_socket && sk->sk_socket->file) {
 557                         struct file *file = sk->sk_socket->file;
 558                         const struct cred *cred = file->f_cred;
 559                         struct user_namespace *user_ns = inst->peer_user_ns;
 560                         __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
 561                         __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
 562                         read_unlock_bh(&sk->sk_callback_lock);
 563                         if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 564                             nla_put_be32(inst->skb, NFULA_GID, gid))
 565                                 goto nla_put_failure;
 566                 } else
 567                         read_unlock_bh(&sk->sk_callback_lock);
 568         }
 569
 570         /* local sequence number */
 571         if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 572             nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 573                 goto nla_put_failure;
 574
 575         /* global sequence number */
 576         if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 577             nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 578                          htonl(atomic_inc_return(&log->global_seq))))
 579                 goto nla_put_failure;
 580
 581         if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
 582                                  NFULA_CT, NFULA_CT_INFO) < 0)
 583                 goto nla_put_failure;
 584
 585         if (data_len) {
 586                 struct nlattr *nla;
 587                 int size = nla_attr_size(data_len);
 588
 589                 if (skb_tailroom(inst->skb) < nla_total_size(data_len))
 590                         goto nla_put_failure;
 591
 592                 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
 593                 nla->nla_type = NFULA_PAYLOAD;
 594                 nla->nla_len = size;
 595
 596                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 597                         BUG();
 598         }
 599
 600         nlh->nlmsg_len = inst->skb->tail - old_tail;
 601         return 0;
 602
 603 nla_put_failure:
 604         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 605         return -1;
 606 }
 607
 608 static struct nf_loginfo default_loginfo = {
 609         .type =         NF_LOG_TYPE_ULOG,
 610         .u = {
 611                 .ulog = {
 612                         .copy_len       = 0xffff,
 613                         .group          = 0,
 614                         .qthreshold     = 1,
 615                 },
 616         },
 617 };
 618
 619 /* log handler for internal netfilter logging api */
 620 void
 621 nfulnl_log_packet(struct net *net,
 622                   u_int8_t pf,
 623                   unsigned int hooknum,
 624                   const struct sk_buff *skb,
 625                   const struct net_device *in,
 626                   const struct net_device *out,
 627                   const struct nf_loginfo *li_user,
 628                   const char *prefix)
 629 {
 630         size_t size;
 631         unsigned int data_len;
 632         struct nfulnl_instance *inst;
 633         const struct nf_loginfo *li;
 634         unsigned int qthreshold;
 635         unsigned int plen;
 636         struct nfnl_log_net *log = nfnl_log_pernet(net);
 637         const struct nfnl_ct_hook *nfnl_ct = NULL;
 638         struct nf_conn *ct = NULL;
 639         enum ip_conntrack_info uninitialized_var(ctinfo);
 640
 641         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 642                 li = li_user;
 643         else
 644                 li = &default_loginfo;
 645
 646         inst = instance_lookup_get(log, li->u.ulog.group);
 647         if (!inst)
 648                 return;
 649
 650         plen = 0;
 651         if (prefix)
 652                 plen = strlen(prefix) + 1;
 653
 654         /* FIXME: do we want to make the size calculation conditional based on
 655          * what is actually present?  way more branches and checks, but more
 656          * memory efficient... */
 657         size =    nlmsg_total_size(sizeof(struct nfgenmsg))
 658                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 659                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 660                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 661 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 662                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 663                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 664 #endif
 665                 + nla_total_size(sizeof(u_int32_t))     /* mark */
 666                 + nla_total_size(sizeof(u_int32_t))     /* uid */
 667                 + nla_total_size(sizeof(u_int32_t))     /* gid */
 668                 + nla_total_size(plen)                  /* prefix */
 669                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 670                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
 671                 + nla_total_size(sizeof(struct nfgenmsg));      /* NLMSG_DONE */
 672
 673         if (in && skb_mac_header_was_set(skb)) {
 674                 size +=   nla_total_size(skb->dev->hard_header_len)
 675                         + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 676                         + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 677         }
 678
 679         spin_lock_bh(&inst->lock);
 680
 681         if (inst->flags & NFULNL_CFG_F_SEQ)
 682                 size += nla_total_size(sizeof(u_int32_t));
 683         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 684                 size += nla_total_size(sizeof(u_int32_t));
 685         if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
 686                 nfnl_ct = rcu_dereference(nfnl_ct_hook);
 687                 if (nfnl_ct != NULL) {
 688                         ct = nfnl_ct->get_ct(skb, &ctinfo);
 689                         if (ct != NULL)
 690                                 size += nfnl_ct->build_size(ct);
 691                 }
 692         }
 693
 694         qthreshold = inst->qthreshold;
 695         /* per-rule qthreshold overrides per-instance */
 696         if (li->u.ulog.qthreshold)
 697                 if (qthreshold > li->u.ulog.qthreshold)
 698                         qthreshold = li->u.ulog.qthreshold;
 699
 700
 701         switch (inst->copy_mode) {
 702         case NFULNL_COPY_META:
 703         case NFULNL_COPY_NONE:
 704                 data_len = 0;
 705                 break;
 706
 707         case NFULNL_COPY_PACKET:
 708                 if (inst->copy_range > skb->len)
 709                         data_len = skb->len;
 710                 else
 711                         data_len = inst->copy_range;
 712
 713                 size += nla_total_size(data_len);
 714                 break;
 715
 716         case NFULNL_COPY_DISABLED:
 717         default:
 718                 goto unlock_and_release;
 719         }
 720
 721         if (inst->skb && size > skb_tailroom(inst->skb)) {
 722                 /* either the queue len is too high or we don't have
 723                  * enough room in the skb left. flush to userspace. */
 724                 __nfulnl_flush(inst);
 725         }
 726
 727         if (!inst->skb) {
 728                 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
 729                                              inst->nlbufsiz, size);
 730                 if (!inst->skb)
 731                         goto alloc_failure;
 732         }
 733
 734         inst->qlen++;
 735
 736         __build_packet_message(log, inst, skb, data_len, pf,
 737                                 hooknum, in, out, prefix, plen,
 738                                 nfnl_ct, ct, ctinfo);
 739
 740         if (inst->qlen >= qthreshold)
 741                 __nfulnl_flush(inst);
 742         /* timer_pending always called within inst->lock, so there
 743          * is no chance of a race here */
 744         else if (!timer_pending(&inst->timer)) {
 745                 instance_get(inst);
 746                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 747                 add_timer(&inst->timer);
 748         }
 749
 750 unlock_and_release:
 751         spin_unlock_bh(&inst->lock);
 752         instance_put(inst);
 753         return;
 754
 755 alloc_failure:
 756         /* FIXME: statistics */
 757         goto unlock_and_release;
 758 }
 759 EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 760
 761 static int
 762 nfulnl_rcv_nl_event(struct notifier_block *this,
 763                    unsigned long event, void *ptr)
 764 {
 765         struct netlink_notify *n = ptr;
 766         struct nfnl_log_net *log = nfnl_log_pernet(n->net);
 767
 768         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 769                 int i;
 770
 771                 /* destroy all instances for this portid */
 772                 spin_lock_bh(&log->instances_lock);
 773                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 774                         struct hlist_node *t2;
 775                         struct nfulnl_instance *inst;
 776                         struct hlist_head *head = &log->instance_table[i];
 777
 778                         hlist_for_each_entry_safe(inst, t2, head, hlist) {
 779                                 if (n->portid == inst->peer_portid)
 780                                         __instance_destroy(inst);
 781                         }
 782                 }
 783                 spin_unlock_bh(&log->instances_lock);
 784         }
 785         return NOTIFY_DONE;
 786 }
 787
 788 static struct notifier_block nfulnl_rtnl_notifier = {
 789         .notifier_call  = nfulnl_rcv_nl_event,
 790 };
 791
 792 static int
 793 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 794                    const struct nlmsghdr *nlh,
 795                    const struct nlattr * const nfqa[])
 796 {
 797         return -ENOTSUPP;
 798 }
 799
 800 static struct nf_logger nfulnl_logger __read_mostly = {
 801         .name   = "nfnetlink_log",
 802         .type   = NF_LOG_TYPE_ULOG,
 803         .logfn  = &nfulnl_log_packet,
 804         .me     = THIS_MODULE,
 805 };
 806
 807 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 808         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 809         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 810         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 811         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 812         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 813         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 814 };
 815
 816 static int
 817 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 818                    const struct nlmsghdr *nlh,
 819                    const struct nlattr * const nfula[])
 820 {
 821         struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 822         u_int16_t group_num = ntohs(nfmsg->res_id);
 823         struct nfulnl_instance *inst;
 824         struct nfulnl_msg_config_cmd *cmd = NULL;
 825         struct net *net = sock_net(ctnl);
 826         struct nfnl_log_net *log = nfnl_log_pernet(net);
 827         int ret = 0;
 828         u16 flags = 0;
 829
 830         if (nfula[NFULA_CFG_CMD]) {
 831                 u_int8_t pf = nfmsg->nfgen_family;
 832                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
 833
 834                 /* Commands without queue context */
 835                 switch (cmd->command) {
 836                 case NFULNL_CFG_CMD_PF_BIND:
 837                         return nf_log_bind_pf(net, pf, &nfulnl_logger);
 838                 case NFULNL_CFG_CMD_PF_UNBIND:
 839                         nf_log_unbind_pf(net, pf);
 840                         return 0;
 841                 }
 842         }
 843
 844         inst = instance_lookup_get(log, group_num);
 845         if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
 846                 ret = -EPERM;
 847                 goto out_put;
 848         }
 849
 850         /* Check if we support these flags in first place, dependencies should
 851          * be there too not to break atomicity.
 852          */
 853         if (nfula[NFULA_CFG_FLAGS]) {
 854                 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
 855
 856                 if ((flags & NFULNL_CFG_F_CONNTRACK) &&
 857                     !rcu_access_pointer(nfnl_ct_hook)) {
 858 #ifdef CONFIG_MODULES
 859                         nfnl_unlock(NFNL_SUBSYS_ULOG);
 860                         request_module("ip_conntrack_netlink");
 861                         nfnl_lock(NFNL_SUBSYS_ULOG);
 862                         if (rcu_access_pointer(nfnl_ct_hook)) {
 863                                 ret = -EAGAIN;
 864                                 goto out_put;
 865                         }
 866 #endif
 867                         ret = -EOPNOTSUPP;
 868                         goto out_put;
 869                 }
 870         }
 871
 872         if (cmd != NULL) {
 873                 switch (cmd->command) {
 874                 case NFULNL_CFG_CMD_BIND:
 875                         if (inst) {
 876                                 ret = -EBUSY;
 877                                 goto out_put;
 878                         }
 879
 880                         inst = instance_create(net, group_num,
 881                                                NETLINK_CB(skb).portid,
 882                                                sk_user_ns(NETLINK_CB(skb).sk));
 883                         if (IS_ERR(inst)) {
 884                                 ret = PTR_ERR(inst);
 885                                 goto out;
 886                         }
 887                         break;
 888                 case NFULNL_CFG_CMD_UNBIND:
 889                         if (!inst) {
 890                                 ret = -ENODEV;
 891                                 goto out;
 892                         }
 893
 894                         instance_destroy(log, inst);
 895                         goto out_put;
 896                 default:
 897                         ret = -ENOTSUPP;
 898                         break;
 899                 }
 900         } else if (!inst) {
 901                 ret = -ENODEV;
 902                 goto out;
 903         }
 904
 905         if (nfula[NFULA_CFG_MODE]) {
 906                 struct nfulnl_msg_config_mode *params =
 907                         nla_data(nfula[NFULA_CFG_MODE]);
 908
 909                 nfulnl_set_mode(inst, params->copy_mode,
 910                                 ntohl(params->copy_range));
 911         }
 912
 913         if (nfula[NFULA_CFG_TIMEOUT]) {
 914                 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 915
 916                 nfulnl_set_timeout(inst, ntohl(timeout));
 917         }
 918
 919         if (nfula[NFULA_CFG_NLBUFSIZ]) {
 920                 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 921
 922                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 923         }
 924
 925         if (nfula[NFULA_CFG_QTHRESH]) {
 926                 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 927
 928                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 929         }
 930
 931         if (nfula[NFULA_CFG_FLAGS])
 932                 nfulnl_set_flags(inst, flags);
 933
 934 out_put:
 935         instance_put(inst);
 936 out:
 937         return ret;
 938 }
 939
 940 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 941         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 942                                     .attr_count = NFULA_MAX, },
 943         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 944                                     .attr_count = NFULA_CFG_MAX,
 945                                     .policy = nfula_cfg_policy },
 946 };
 947
 948 static const struct nfnetlink_subsystem nfulnl_subsys = {
 949         .name           = "log",
 950         .subsys_id      = NFNL_SUBSYS_ULOG,
 951         .cb_count       = NFULNL_MSG_MAX,
 952         .cb             = nfulnl_cb,
 953 };
 954
 955 #ifdef CONFIG_PROC_FS
 956 struct iter_state {
 957         struct seq_net_private p;
 958         unsigned int bucket;
 959 };
 960
 961 static struct hlist_node *get_first(struct net *net, struct iter_state *st)
 962 {
 963         struct nfnl_log_net *log;
 964         if (!st)
 965                 return NULL;
 966
 967         log = nfnl_log_pernet(net);
 968
 969         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 970                 struct hlist_head *head = &log->instance_table[st->bucket];
 971
 972                 if (!hlist_empty(head))
 973                         return rcu_dereference_bh(hlist_first_rcu(head));
 974         }
 975         return NULL;
 976 }
 977
 978 static struct hlist_node *get_next(struct net *net, struct iter_state *st,
 979                                    struct hlist_node *h)
 980 {
 981         h = rcu_dereference_bh(hlist_next_rcu(h));
 982         while (!h) {
 983                 struct nfnl_log_net *log;
 984                 struct hlist_head *head;
 985
 986                 if (++st->bucket >= INSTANCE_BUCKETS)
 987                         return NULL;
 988
 989                 log = nfnl_log_pernet(net);
 990                 head = &log->instance_table[st->bucket];
 991                 h = rcu_dereference_bh(hlist_first_rcu(head));
 992         }
 993         return h;
 994 }
 995
 996 static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
 997                                   loff_t pos)
 998 {
 999         struct hlist_node *head;
1000         head = get_first(net, st);
1001
1002         if (head)
1003                 while (pos && (head = get_next(net, st, head)))
1004                         pos--;
1005         return pos ? NULL : head;
1006 }
1007
1008 static void *seq_start(struct seq_file *s, loff_t *pos)
1009         __acquires(rcu_bh)
1010 {
1011         rcu_read_lock_bh();
1012         return get_idx(seq_file_net(s), s->private, *pos);
1013 }
1014
1015 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
1016 {
1017         (*pos)++;
1018         return get_next(seq_file_net(s), s->private, v);
1019 }
1020
1021 static void seq_stop(struct seq_file *s, void *v)
1022         __releases(rcu_bh)
1023 {
1024         rcu_read_unlock_bh();
1025 }
1026
1027 static int seq_show(struct seq_file *s, void *v)
1028 {
1029         const struct nfulnl_instance *inst = v;
1030
1031         seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1032                    inst->group_num,
1033                    inst->peer_portid, inst->qlen,
1034                    inst->copy_mode, inst->copy_range,
1035                    inst->flushtimeout, atomic_read(&inst->use));
1036
1037         return 0;
1038 }
1039
1040 static const struct seq_operations nful_seq_ops = {
1041         .start  = seq_start,
1042         .next   = seq_next,
1043         .stop   = seq_stop,
1044         .show   = seq_show,
1045 };
1046
1047 static int nful_open(struct inode *inode, struct file *file)
1048 {
1049         return seq_open_net(inode, file, &nful_seq_ops,
1050                             sizeof(struct iter_state));
1051 }
1052
1053 static const struct file_operations nful_file_ops = {
1054         .owner   = THIS_MODULE,
1055         .open    = nful_open,
1056         .read    = seq_read,
1057         .llseek  = seq_lseek,
1058         .release = seq_release_net,
1059 };
1060
1061 #endif /* PROC_FS */
1062
1063 static int __net_init nfnl_log_net_init(struct net *net)
1064 {
1065         unsigned int i;
1066         struct nfnl_log_net *log = nfnl_log_pernet(net);
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         if (!proc_create("nfnetlink_log", 0440,
1074                          net->nf.proc_netfilter, &nful_file_ops))
1075                 return -ENOMEM;
1076 #endif
1077         return 0;
1078 }
1079
1080 static void __net_exit nfnl_log_net_exit(struct net *net)
1081 {
1082 #ifdef CONFIG_PROC_FS
1083         remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1084 #endif
1085         nf_log_unset(net, &nfulnl_logger);
1086 }
1087
1088 static struct pernet_operations nfnl_log_net_ops = {
1089         .init   = nfnl_log_net_init,
1090         .exit   = nfnl_log_net_exit,
1091         .id     = &nfnl_log_net_id,
1092         .size   = sizeof(struct nfnl_log_net),
1093 };
1094
1095 static int __init nfnetlink_log_init(void)
1096 {
1097         int status;
1098
1099         status = register_pernet_subsys(&nfnl_log_net_ops);
1100         if (status < 0) {
1101                 pr_err("failed to register pernet ops\n");
1102                 goto out;
1103         }
1104
1105         netlink_register_notifier(&nfulnl_rtnl_notifier);
1106         status = nfnetlink_subsys_register(&nfulnl_subsys);
1107         if (status < 0) {
1108                 pr_err("failed to create netlink socket\n");
1109                 goto cleanup_netlink_notifier;
1110         }
1111
1112         status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1113         if (status < 0) {
1114                 pr_err("failed to register logger\n");
1115                 goto cleanup_subsys;
1116         }
1117
1118         return status;
1119
1120 cleanup_subsys:
1121         nfnetlink_subsys_unregister(&nfulnl_subsys);
1122 cleanup_netlink_notifier:
1123         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1124         unregister_pernet_subsys(&nfnl_log_net_ops);
1125 out:
1126         return status;
1127 }
1128
1129 static void __exit nfnetlink_log_fini(void)
1130 {
1131         nf_log_unregister(&nfulnl_logger);
1132         nfnetlink_subsys_unregister(&nfulnl_subsys);
1133         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1134         unregister_pernet_subsys(&nfnl_log_net_ops);
1135 }
1136
1137 MODULE_DESCRIPTION("netfilter userspace logging");
1138 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1139 MODULE_LICENSE("GPL");
1140 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1141 MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1142 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1143 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1144
1145 module_init(nfnetlink_log_init);
1146 module_exit(nfnetlink_log_fini);