net/netfilter/nfnetlink_log.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This is a module which is used for logging packets to userspace via
   4  * nfetlink.
   5  *
   6  * (C) 2005 by Harald Welte <laforge@netfilter.org>
   7  * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
   8  *
   9  * Based on the old ipv4-only ipt_ULOG.c:
  10  * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/module.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/if_arp.h>
  18 #include <linux/init.h>
  19 #include <linux/ip.h>
  20 #include <linux/ipv6.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/netfilter.h>
  23 #include <linux/netfilter_bridge.h>
  24 #include <net/netlink.h>
  25 #include <linux/netfilter/nfnetlink.h>
  26 #include <linux/netfilter/nfnetlink_log.h>
  27 #include <linux/netfilter/nf_conntrack_common.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/sysctl.h>
  30 #include <linux/proc_fs.h>
  31 #include <linux/security.h>
  32 #include <linux/list.h>
  33 #include <linux/slab.h>
  34 #include <net/sock.h>
  35 #include <net/netfilter/nf_log.h>
  36 #include <net/netns/generic.h>
  37
  38 #include <linux/atomic.h>
  39 #include <linux/refcount.h>
  40
  41
  42 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
  43 #include "../bridge/br_private.h"
  44 #endif
  45
  46 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
  47 #include <net/netfilter/nf_conntrack.h>
  48 #endif
  49
  50 #define NFULNL_COPY_DISABLED    0xff
  51 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  52 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  53 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  54 /* max packet size is limited by 16-bit struct nfattr nfa_len field */
  55 #define NFULNL_COPY_RANGE_MAX   (0xFFFF - NLA_HDRLEN)
  56
  57 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  58                                      printk(x, ## args); } while (0);
  59
  60 struct nfulnl_instance {
  61         struct hlist_node hlist;        /* global list of instances */
  62         spinlock_t lock;
  63         refcount_t use;                 /* use count */
  64
  65         unsigned int qlen;              /* number of nlmsgs in skb */
  66         struct sk_buff *skb;            /* pre-allocatd skb */
  67         struct timer_list timer;
  68         struct net *net;
  69         netns_tracker ns_tracker;
  70         struct user_namespace *peer_user_ns;    /* User namespace of the peer process */
  71         u32 peer_portid;                /* PORTID of the peer process */
  72
  73         /* configurable parameters */
  74         unsigned int flushtimeout;      /* timeout until queue flush */
  75         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  76         unsigned int qthreshold;        /* threshold of the queue */
  77         u_int32_t copy_range;
  78         u_int32_t seq;                  /* instance-local sequential counter */
  79         u_int16_t group_num;            /* number of this queue */
  80         u_int16_t flags;
  81         u_int8_t copy_mode;
  82         struct rcu_head rcu;
  83 };
  84
  85 #define INSTANCE_BUCKETS        16
  86
  87 static unsigned int nfnl_log_net_id __read_mostly;
  88
  89 struct nfnl_log_net {
  90         spinlock_t instances_lock;
  91         struct hlist_head instance_table[INSTANCE_BUCKETS];
  92         atomic_t global_seq;
  93 };
  94
  95 static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
  96 {
  97         return net_generic(net, nfnl_log_net_id);
  98 }
  99
 100 static inline u_int8_t instance_hashfn(u_int16_t group_num)
 101 {
 102         return ((group_num & 0xff) % INSTANCE_BUCKETS);
 103 }
 104
 105 static struct nfulnl_instance *
 106 __instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
 107 {
 108         struct hlist_head *head;
 109         struct nfulnl_instance *inst;
 110
 111         head = &log->instance_table[instance_hashfn(group_num)];
 112         hlist_for_each_entry_rcu(inst, head, hlist) {
 113                 if (inst->group_num == group_num)
 114                         return inst;
 115         }
 116         return NULL;
 117 }
 118
 119 static inline void
 120 instance_get(struct nfulnl_instance *inst)
 121 {
 122         refcount_inc(&inst->use);
 123 }
 124
 125 static struct nfulnl_instance *
 126 instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
 127 {
 128         struct nfulnl_instance *inst;
 129
 130         rcu_read_lock_bh();
 131         inst = __instance_lookup(log, group_num);
 132         if (inst && !refcount_inc_not_zero(&inst->use))
 133                 inst = NULL;
 134         rcu_read_unlock_bh();
 135
 136         return inst;
 137 }
 138
 139 static void nfulnl_instance_free_rcu(struct rcu_head *head)
 140 {
 141         struct nfulnl_instance *inst =
 142                 container_of(head, struct nfulnl_instance, rcu);
 143
 144         put_net_track(inst->net, &inst->ns_tracker);
 145         kfree(inst);
 146         module_put(THIS_MODULE);
 147 }
 148
 149 static void
 150 instance_put(struct nfulnl_instance *inst)
 151 {
 152         if (inst && refcount_dec_and_test(&inst->use))
 153                 call_rcu(&inst->rcu, nfulnl_instance_free_rcu);
 154 }
 155
 156 static void nfulnl_timer(struct timer_list *t);
 157
 158 static struct nfulnl_instance *
 159 instance_create(struct net *net, u_int16_t group_num,
 160                 u32 portid, struct user_namespace *user_ns)
 161 {
 162         struct nfulnl_instance *inst;
 163         struct nfnl_log_net *log = nfnl_log_pernet(net);
 164         int err;
 165
 166         spin_lock_bh(&log->instances_lock);
 167         if (__instance_lookup(log, group_num)) {
 168                 err = -EEXIST;
 169                 goto out_unlock;
 170         }
 171
 172         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 173         if (!inst) {
 174                 err = -ENOMEM;
 175                 goto out_unlock;
 176         }
 177
 178         if (!try_module_get(THIS_MODULE)) {
 179                 kfree(inst);
 180                 err = -EAGAIN;
 181                 goto out_unlock;
 182         }
 183
 184         INIT_HLIST_NODE(&inst->hlist);
 185         spin_lock_init(&inst->lock);
 186         /* needs to be two, since we _put() after creation */
 187         refcount_set(&inst->use, 2);
 188
 189         timer_setup(&inst->timer, nfulnl_timer, 0);
 190
 191         inst->net = get_net_track(net, &inst->ns_tracker, GFP_ATOMIC);
 192         inst->peer_user_ns = user_ns;
 193         inst->peer_portid = portid;
 194         inst->group_num = group_num;
 195
 196         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 197         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 198         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 199         inst->copy_mode         = NFULNL_COPY_PACKET;
 200         inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 201
 202         hlist_add_head_rcu(&inst->hlist,
 203                        &log->instance_table[instance_hashfn(group_num)]);
 204
 205
 206         spin_unlock_bh(&log->instances_lock);
 207
 208         return inst;
 209
 210 out_unlock:
 211         spin_unlock_bh(&log->instances_lock);
 212         return ERR_PTR(err);
 213 }
 214
 215 static void __nfulnl_flush(struct nfulnl_instance *inst);
 216
 217 /* called with BH disabled */
 218 static void
 219 __instance_destroy(struct nfulnl_instance *inst)
 220 {
 221         /* first pull it out of the global list */
 222         hlist_del_rcu(&inst->hlist);
 223
 224         /* then flush all pending packets from skb */
 225
 226         spin_lock(&inst->lock);
 227
 228         /* lockless readers wont be able to use us */
 229         inst->copy_mode = NFULNL_COPY_DISABLED;
 230
 231         if (inst->skb)
 232                 __nfulnl_flush(inst);
 233         spin_unlock(&inst->lock);
 234
 235         /* and finally put the refcount */
 236         instance_put(inst);
 237 }
 238
 239 static inline void
 240 instance_destroy(struct nfnl_log_net *log,
 241                  struct nfulnl_instance *inst)
 242 {
 243         spin_lock_bh(&log->instances_lock);
 244         __instance_destroy(inst);
 245         spin_unlock_bh(&log->instances_lock);
 246 }
 247
 248 static int
 249 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 250                   unsigned int range)
 251 {
 252         int status = 0;
 253
 254         spin_lock_bh(&inst->lock);
 255
 256         switch (mode) {
 257         case NFULNL_COPY_NONE:
 258         case NFULNL_COPY_META:
 259                 inst->copy_mode = mode;
 260                 inst->copy_range = 0;
 261                 break;
 262
 263         case NFULNL_COPY_PACKET:
 264                 inst->copy_mode = mode;
 265                 if (range == 0)
 266                         range = NFULNL_COPY_RANGE_MAX;
 267                 inst->copy_range = min_t(unsigned int,
 268                                          range, NFULNL_COPY_RANGE_MAX);
 269                 break;
 270
 271         default:
 272                 status = -EINVAL;
 273                 break;
 274         }
 275
 276         spin_unlock_bh(&inst->lock);
 277
 278         return status;
 279 }
 280
 281 static int
 282 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 283 {
 284         int status;
 285
 286         spin_lock_bh(&inst->lock);
 287         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 288                 status = -ERANGE;
 289         else if (nlbufsiz > 131072)
 290                 status = -ERANGE;
 291         else {
 292                 inst->nlbufsiz = nlbufsiz;
 293                 status = 0;
 294         }
 295         spin_unlock_bh(&inst->lock);
 296
 297         return status;
 298 }
 299
 300 static void
 301 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 302 {
 303         spin_lock_bh(&inst->lock);
 304         inst->flushtimeout = timeout;
 305         spin_unlock_bh(&inst->lock);
 306 }
 307
 308 static void
 309 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 310 {
 311         spin_lock_bh(&inst->lock);
 312         inst->qthreshold = qthresh;
 313         spin_unlock_bh(&inst->lock);
 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 = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN);
 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 = alloc_skb(pkt_size, GFP_ATOMIC);
 344                 }
 345         }
 346
 347         return skb;
 348 }
 349
 350 static void
 351 __nfulnl_send(struct nfulnl_instance *inst)
 352 {
 353         if (inst->qlen > 1) {
 354                 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 355                                                  NLMSG_DONE,
 356                                                  sizeof(struct nfgenmsg),
 357                                                  0);
 358                 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
 359                               inst->skb->len, skb_tailroom(inst->skb))) {
 360                         kfree_skb(inst->skb);
 361                         goto out;
 362                 }
 363         }
 364         nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid);
 365 out:
 366         inst->qlen = 0;
 367         inst->skb = NULL;
 368 }
 369
 370 static void
 371 __nfulnl_flush(struct nfulnl_instance *inst)
 372 {
 373         /* timer holds a reference */
 374         if (del_timer(&inst->timer))
 375                 instance_put(inst);
 376         if (inst->skb)
 377                 __nfulnl_send(inst);
 378 }
 379
 380 static void
 381 nfulnl_timer(struct timer_list *t)
 382 {
 383         struct nfulnl_instance *inst = from_timer(inst, t, timer);
 384
 385         spin_lock_bh(&inst->lock);
 386         if (inst->skb)
 387                 __nfulnl_send(inst);
 388         spin_unlock_bh(&inst->lock);
 389         instance_put(inst);
 390 }
 391
 392 static u32 nfulnl_get_bridge_size(const struct sk_buff *skb)
 393 {
 394         u32 size = 0;
 395
 396         if (!skb_mac_header_was_set(skb))
 397                 return 0;
 398
 399         if (skb_vlan_tag_present(skb)) {
 400                 size += nla_total_size(0); /* nested */
 401                 size += nla_total_size(sizeof(u16)); /* id */
 402                 size += nla_total_size(sizeof(u16)); /* tag */
 403         }
 404
 405         if (skb->network_header > skb->mac_header)
 406                 size += nla_total_size(skb->network_header - skb->mac_header);
 407
 408         return size;
 409 }
 410
 411 static int nfulnl_put_bridge(struct nfulnl_instance *inst, const struct sk_buff *skb)
 412 {
 413         if (!skb_mac_header_was_set(skb))
 414                 return 0;
 415
 416         if (skb_vlan_tag_present(skb)) {
 417                 struct nlattr *nest;
 418
 419                 nest = nla_nest_start(inst->skb, NFULA_VLAN);
 420                 if (!nest)
 421                         goto nla_put_failure;
 422
 423                 if (nla_put_be16(inst->skb, NFULA_VLAN_TCI, htons(skb->vlan_tci)) ||
 424                     nla_put_be16(inst->skb, NFULA_VLAN_PROTO, skb->vlan_proto))
 425                         goto nla_put_failure;
 426
 427                 nla_nest_end(inst->skb, nest);
 428         }
 429
 430         if (skb->mac_header < skb->network_header) {
 431                 int len = (int)(skb->network_header - skb->mac_header);
 432
 433                 if (nla_put(inst->skb, NFULA_L2HDR, len, skb_mac_header(skb)))
 434                         goto nla_put_failure;
 435         }
 436
 437         return 0;
 438
 439 nla_put_failure:
 440         return -1;
 441 }
 442
 443 /* This is an inline function, we don't really care about a long
 444  * list of arguments */
 445 static inline int
 446 __build_packet_message(struct nfnl_log_net *log,
 447                         struct nfulnl_instance *inst,
 448                         const struct sk_buff *skb,
 449                         unsigned int data_len,
 450                         u_int8_t pf,
 451                         unsigned int hooknum,
 452                         const struct net_device *indev,
 453                         const struct net_device *outdev,
 454                         const char *prefix, unsigned int plen,
 455                         const struct nfnl_ct_hook *nfnl_ct,
 456                         struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 457 {
 458         struct nfulnl_msg_packet_hdr pmsg;
 459         struct nlmsghdr *nlh;
 460         sk_buff_data_t old_tail = inst->skb->tail;
 461         struct sock *sk;
 462         const unsigned char *hwhdrp;
 463         ktime_t tstamp;
 464
 465         nlh = nfnl_msg_put(inst->skb, 0, 0,
 466                            nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET),
 467                            0, pf, NFNETLINK_V0, htons(inst->group_num));
 468         if (!nlh)
 469                 return -1;
 470
 471         memset(&pmsg, 0, sizeof(pmsg));
 472         pmsg.hw_protocol        = skb->protocol;
 473         pmsg.hook               = hooknum;
 474
 475         if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
 476                 goto nla_put_failure;
 477
 478         if (prefix &&
 479             nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
 480                 goto nla_put_failure;
 481
 482         if (indev) {
 483 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 484                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 485                                  htonl(indev->ifindex)))
 486                         goto nla_put_failure;
 487 #else
 488                 if (pf == PF_BRIDGE) {
 489                         /* Case 1: outdev is physical input device, we need to
 490                          * look for bridge group (when called from
 491                          * netfilter_bridge) */
 492                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 493                                          htonl(indev->ifindex)) ||
 494                         /* this is the bridge group "brX" */
 495                         /* rcu_read_lock()ed by nf_hook_thresh or
 496                          * nf_log_packet.
 497                          */
 498                             nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 499                                          htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 500                                 goto nla_put_failure;
 501                 } else {
 502                         struct net_device *physindev;
 503
 504                         /* Case 2: indev is bridge group, we need to look for
 505                          * physical device (when called from ipv4) */
 506                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 507                                          htonl(indev->ifindex)))
 508                                 goto nla_put_failure;
 509
 510                         physindev = nf_bridge_get_physindev(skb);
 511                         if (physindev &&
 512                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 513                                          htonl(physindev->ifindex)))
 514                                 goto nla_put_failure;
 515                 }
 516 #endif
 517         }
 518
 519         if (outdev) {
 520 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 521                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 522                                  htonl(outdev->ifindex)))
 523                         goto nla_put_failure;
 524 #else
 525                 if (pf == PF_BRIDGE) {
 526                         /* Case 1: outdev is physical output device, we need to
 527                          * look for bridge group (when called from
 528                          * netfilter_bridge) */
 529                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 530                                          htonl(outdev->ifindex)) ||
 531                         /* this is the bridge group "brX" */
 532                         /* rcu_read_lock()ed by nf_hook_thresh or
 533                          * nf_log_packet.
 534                          */
 535                             nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 536                                          htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 537                                 goto nla_put_failure;
 538                 } else {
 539                         struct net_device *physoutdev;
 540
 541                         /* Case 2: indev is a bridge group, we need to look
 542                          * for physical device (when called from ipv4) */
 543                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 544                                          htonl(outdev->ifindex)))
 545                                 goto nla_put_failure;
 546
 547                         physoutdev = nf_bridge_get_physoutdev(skb);
 548                         if (physoutdev &&
 549                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 550                                          htonl(physoutdev->ifindex)))
 551                                 goto nla_put_failure;
 552                 }
 553 #endif
 554         }
 555
 556         if (skb->mark &&
 557             nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
 558                 goto nla_put_failure;
 559
 560         if (indev && skb->dev &&
 561             skb_mac_header_was_set(skb) &&
 562             skb_mac_header_len(skb) != 0) {
 563                 struct nfulnl_msg_packet_hw phw;
 564                 int len;
 565
 566                 memset(&phw, 0, sizeof(phw));
 567                 len = dev_parse_header(skb, phw.hw_addr);
 568                 if (len > 0) {
 569                         phw.hw_addrlen = htons(len);
 570                         if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 571                                 goto nla_put_failure;
 572                 }
 573         }
 574
 575         if (indev && skb_mac_header_was_set(skb)) {
 576                 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 577                     nla_put_be16(inst->skb, NFULA_HWLEN,
 578                                  htons(skb->dev->hard_header_len)))
 579                         goto nla_put_failure;
 580
 581                 hwhdrp = skb_mac_header(skb);
 582
 583                 if (skb->dev->type == ARPHRD_SIT)
 584                         hwhdrp -= ETH_HLEN;
 585
 586                 if (hwhdrp >= skb->head &&
 587                     nla_put(inst->skb, NFULA_HWHEADER,
 588                             skb->dev->hard_header_len, hwhdrp))
 589                         goto nla_put_failure;
 590         }
 591
 592         tstamp = skb_tstamp_cond(skb, false);
 593         if (hooknum <= NF_INET_FORWARD && tstamp) {
 594                 struct nfulnl_msg_packet_timestamp ts;
 595                 struct timespec64 kts = ktime_to_timespec64(tstamp);
 596                 ts.sec = cpu_to_be64(kts.tv_sec);
 597                 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
 598
 599                 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 600                         goto nla_put_failure;
 601         }
 602
 603         /* UID */
 604         sk = skb->sk;
 605         if (sk && sk_fullsock(sk)) {
 606                 read_lock_bh(&sk->sk_callback_lock);
 607                 if (sk->sk_socket && sk->sk_socket->file) {
 608                         struct file *file = sk->sk_socket->file;
 609                         const struct cred *cred = file->f_cred;
 610                         struct user_namespace *user_ns = inst->peer_user_ns;
 611                         __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
 612                         __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
 613                         read_unlock_bh(&sk->sk_callback_lock);
 614                         if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 615                             nla_put_be32(inst->skb, NFULA_GID, gid))
 616                                 goto nla_put_failure;
 617                 } else
 618                         read_unlock_bh(&sk->sk_callback_lock);
 619         }
 620
 621         /* local sequence number */
 622         if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 623             nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 624                 goto nla_put_failure;
 625
 626         /* global sequence number */
 627         if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 628             nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 629                          htonl(atomic_inc_return(&log->global_seq))))
 630                 goto nla_put_failure;
 631
 632         if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
 633                                  NFULA_CT, NFULA_CT_INFO) < 0)
 634                 goto nla_put_failure;
 635
 636         if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) &&
 637             nfulnl_put_bridge(inst, skb) < 0)
 638                 goto nla_put_failure;
 639
 640         if (data_len) {
 641                 struct nlattr *nla;
 642                 int size = nla_attr_size(data_len);
 643
 644                 if (skb_tailroom(inst->skb) < nla_total_size(data_len))
 645                         goto nla_put_failure;
 646
 647                 nla = skb_put(inst->skb, nla_total_size(data_len));
 648                 nla->nla_type = NFULA_PAYLOAD;
 649                 nla->nla_len = size;
 650
 651                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 652                         BUG();
 653         }
 654
 655         nlh->nlmsg_len = inst->skb->tail - old_tail;
 656         return 0;
 657
 658 nla_put_failure:
 659         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 660         return -1;
 661 }
 662
 663 static const struct nf_loginfo default_loginfo = {
 664         .type =         NF_LOG_TYPE_ULOG,
 665         .u = {
 666                 .ulog = {
 667                         .copy_len       = 0xffff,
 668                         .group          = 0,
 669                         .qthreshold     = 1,
 670                 },
 671         },
 672 };
 673
 674 /* log handler for internal netfilter logging api */
 675 static void
 676 nfulnl_log_packet(struct net *net,
 677                   u_int8_t pf,
 678                   unsigned int hooknum,
 679                   const struct sk_buff *skb,
 680                   const struct net_device *in,
 681                   const struct net_device *out,
 682                   const struct nf_loginfo *li_user,
 683                   const char *prefix)
 684 {
 685         size_t size;
 686         unsigned int data_len;
 687         struct nfulnl_instance *inst;
 688         const struct nf_loginfo *li;
 689         unsigned int qthreshold;
 690         unsigned int plen = 0;
 691         struct nfnl_log_net *log = nfnl_log_pernet(net);
 692         const struct nfnl_ct_hook *nfnl_ct = NULL;
 693         struct nf_conn *ct = NULL;
 694         enum ip_conntrack_info ctinfo;
 695
 696         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 697                 li = li_user;
 698         else
 699                 li = &default_loginfo;
 700
 701         inst = instance_lookup_get(log, li->u.ulog.group);
 702         if (!inst)
 703                 return;
 704
 705         if (prefix)
 706                 plen = strlen(prefix) + 1;
 707
 708         /* FIXME: do we want to make the size calculation conditional based on
 709          * what is actually present?  way more branches and checks, but more
 710          * memory efficient... */
 711         size = nlmsg_total_size(sizeof(struct nfgenmsg))
 712                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 713                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 714                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 715 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 716                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 717                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 718 #endif
 719                 + nla_total_size(sizeof(u_int32_t))     /* mark */
 720                 + nla_total_size(sizeof(u_int32_t))     /* uid */
 721                 + nla_total_size(sizeof(u_int32_t))     /* gid */
 722                 + nla_total_size(plen)                  /* prefix */
 723                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 724                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
 725                 + nla_total_size(sizeof(struct nfgenmsg));      /* NLMSG_DONE */
 726
 727         if (in && skb_mac_header_was_set(skb)) {
 728                 size += nla_total_size(skb->dev->hard_header_len)
 729                         + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 730                         + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 731         }
 732
 733         spin_lock_bh(&inst->lock);
 734
 735         if (inst->flags & NFULNL_CFG_F_SEQ)
 736                 size += nla_total_size(sizeof(u_int32_t));
 737         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 738                 size += nla_total_size(sizeof(u_int32_t));
 739 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 740         if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
 741                 nfnl_ct = rcu_dereference(nfnl_ct_hook);
 742                 if (nfnl_ct != NULL) {
 743                         ct = nf_ct_get(skb, &ctinfo);
 744                         if (ct != NULL)
 745                                 size += nfnl_ct->build_size(ct);
 746                 }
 747         }
 748 #endif
 749         if (pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE)
 750                 size += nfulnl_get_bridge_size(skb);
 751
 752         qthreshold = inst->qthreshold;
 753         /* per-rule qthreshold overrides per-instance */
 754         if (li->u.ulog.qthreshold)
 755                 if (qthreshold > li->u.ulog.qthreshold)
 756                         qthreshold = li->u.ulog.qthreshold;
 757
 758
 759         switch (inst->copy_mode) {
 760         case NFULNL_COPY_META:
 761         case NFULNL_COPY_NONE:
 762                 data_len = 0;
 763                 break;
 764
 765         case NFULNL_COPY_PACKET:
 766                 data_len = inst->copy_range;
 767                 if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) &&
 768                     (li->u.ulog.copy_len < data_len))
 769                         data_len = li->u.ulog.copy_len;
 770
 771                 if (data_len > skb->len)
 772                         data_len = skb->len;
 773
 774                 size += nla_total_size(data_len);
 775                 break;
 776
 777         case NFULNL_COPY_DISABLED:
 778         default:
 779                 goto unlock_and_release;
 780         }
 781
 782         if (inst->skb && size > skb_tailroom(inst->skb)) {
 783                 /* either the queue len is too high or we don't have
 784                  * enough room in the skb left. flush to userspace. */
 785                 __nfulnl_flush(inst);
 786         }
 787
 788         if (!inst->skb) {
 789                 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
 790                                              inst->nlbufsiz, size);
 791                 if (!inst->skb)
 792                         goto alloc_failure;
 793         }
 794
 795         inst->qlen++;
 796
 797         __build_packet_message(log, inst, skb, data_len, pf,
 798                                 hooknum, in, out, prefix, plen,
 799                                 nfnl_ct, ct, ctinfo);
 800
 801         if (inst->qlen >= qthreshold)
 802                 __nfulnl_flush(inst);
 803         /* timer_pending always called within inst->lock, so there
 804          * is no chance of a race here */
 805         else if (!timer_pending(&inst->timer)) {
 806                 instance_get(inst);
 807                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 808                 add_timer(&inst->timer);
 809         }
 810
 811 unlock_and_release:
 812         spin_unlock_bh(&inst->lock);
 813         instance_put(inst);
 814         return;
 815
 816 alloc_failure:
 817         /* FIXME: statistics */
 818         goto unlock_and_release;
 819 }
 820
 821 static int
 822 nfulnl_rcv_nl_event(struct notifier_block *this,
 823                    unsigned long event, void *ptr)
 824 {
 825         struct netlink_notify *n = ptr;
 826         struct nfnl_log_net *log = nfnl_log_pernet(n->net);
 827
 828         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 829                 int i;
 830
 831                 /* destroy all instances for this portid */
 832                 spin_lock_bh(&log->instances_lock);
 833                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 834                         struct hlist_node *t2;
 835                         struct nfulnl_instance *inst;
 836                         struct hlist_head *head = &log->instance_table[i];
 837
 838                         hlist_for_each_entry_safe(inst, t2, head, hlist) {
 839                                 if (n->portid == inst->peer_portid)
 840                                         __instance_destroy(inst);
 841                         }
 842                 }
 843                 spin_unlock_bh(&log->instances_lock);
 844         }
 845         return NOTIFY_DONE;
 846 }
 847
 848 static struct notifier_block nfulnl_rtnl_notifier = {
 849         .notifier_call  = nfulnl_rcv_nl_event,
 850 };
 851
 852 static int nfulnl_recv_unsupp(struct sk_buff *skb, const struct nfnl_info *info,
 853                               const struct nlattr * const nfula[])
 854 {
 855         return -ENOTSUPP;
 856 }
 857
 858 static struct nf_logger nfulnl_logger __read_mostly = {
 859         .name   = "nfnetlink_log",
 860         .type   = NF_LOG_TYPE_ULOG,
 861         .logfn  = nfulnl_log_packet,
 862         .me     = THIS_MODULE,
 863 };
 864
 865 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 866         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 867         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 868         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 869         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 870         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 871         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 872 };
 873
 874 static int nfulnl_recv_config(struct sk_buff *skb, const struct nfnl_info *info,
 875                               const struct nlattr * const nfula[])
 876 {
 877         struct nfnl_log_net *log = nfnl_log_pernet(info->net);
 878         u_int16_t group_num = ntohs(info->nfmsg->res_id);
 879         struct nfulnl_msg_config_cmd *cmd = NULL;
 880         struct nfulnl_instance *inst;
 881         u16 flags = 0;
 882         int ret = 0;
 883
 884         if (nfula[NFULA_CFG_CMD]) {
 885                 u_int8_t pf = info->nfmsg->nfgen_family;
 886                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
 887
 888                 /* Commands without queue context */
 889                 switch (cmd->command) {
 890                 case NFULNL_CFG_CMD_PF_BIND:
 891                         return nf_log_bind_pf(info->net, pf, &nfulnl_logger);
 892                 case NFULNL_CFG_CMD_PF_UNBIND:
 893                         nf_log_unbind_pf(info->net, pf);
 894                         return 0;
 895                 }
 896         }
 897
 898         inst = instance_lookup_get(log, group_num);
 899         if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
 900                 ret = -EPERM;
 901                 goto out_put;
 902         }
 903
 904         /* Check if we support these flags in first place, dependencies should
 905          * be there too not to break atomicity.
 906          */
 907         if (nfula[NFULA_CFG_FLAGS]) {
 908                 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
 909
 910                 if ((flags & NFULNL_CFG_F_CONNTRACK) &&
 911                     !rcu_access_pointer(nfnl_ct_hook)) {
 912 #ifdef CONFIG_MODULES
 913                         nfnl_unlock(NFNL_SUBSYS_ULOG);
 914                         request_module("ip_conntrack_netlink");
 915                         nfnl_lock(NFNL_SUBSYS_ULOG);
 916                         if (rcu_access_pointer(nfnl_ct_hook)) {
 917                                 ret = -EAGAIN;
 918                                 goto out_put;
 919                         }
 920 #endif
 921                         ret = -EOPNOTSUPP;
 922                         goto out_put;
 923                 }
 924         }
 925
 926         if (cmd != NULL) {
 927                 switch (cmd->command) {
 928                 case NFULNL_CFG_CMD_BIND:
 929                         if (inst) {
 930                                 ret = -EBUSY;
 931                                 goto out_put;
 932                         }
 933
 934                         inst = instance_create(info->net, group_num,
 935                                                NETLINK_CB(skb).portid,
 936                                                sk_user_ns(NETLINK_CB(skb).sk));
 937                         if (IS_ERR(inst)) {
 938                                 ret = PTR_ERR(inst);
 939                                 goto out;
 940                         }
 941                         break;
 942                 case NFULNL_CFG_CMD_UNBIND:
 943                         if (!inst) {
 944                                 ret = -ENODEV;
 945                                 goto out;
 946                         }
 947
 948                         instance_destroy(log, inst);
 949                         goto out_put;
 950                 default:
 951                         ret = -ENOTSUPP;
 952                         goto out_put;
 953                 }
 954         } else if (!inst) {
 955                 ret = -ENODEV;
 956                 goto out;
 957         }
 958
 959         if (nfula[NFULA_CFG_MODE]) {
 960                 struct nfulnl_msg_config_mode *params =
 961                         nla_data(nfula[NFULA_CFG_MODE]);
 962
 963                 nfulnl_set_mode(inst, params->copy_mode,
 964                                 ntohl(params->copy_range));
 965         }
 966
 967         if (nfula[NFULA_CFG_TIMEOUT]) {
 968                 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 969
 970                 nfulnl_set_timeout(inst, ntohl(timeout));
 971         }
 972
 973         if (nfula[NFULA_CFG_NLBUFSIZ]) {
 974                 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 975
 976                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 977         }
 978
 979         if (nfula[NFULA_CFG_QTHRESH]) {
 980                 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 981
 982                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 983         }
 984
 985         if (nfula[NFULA_CFG_FLAGS])
 986                 nfulnl_set_flags(inst, flags);
 987
 988 out_put:
 989         instance_put(inst);
 990 out:
 991         return ret;
 992 }
 993
 994 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 995         [NFULNL_MSG_PACKET]     = {
 996                 .call           = nfulnl_recv_unsupp,
 997                 .type           = NFNL_CB_MUTEX,
 998                 .attr_count     = NFULA_MAX,
 999         },
1000         [NFULNL_MSG_CONFIG]     = {
1001                 .call           = nfulnl_recv_config,
1002                 .type           = NFNL_CB_MUTEX,
1003                 .attr_count     = NFULA_CFG_MAX,
1004                 .policy         = nfula_cfg_policy
1005         },
1006 };
1007
1008 static const struct nfnetlink_subsystem nfulnl_subsys = {
1009         .name           = "log",
1010         .subsys_id      = NFNL_SUBSYS_ULOG,
1011         .cb_count       = NFULNL_MSG_MAX,
1012         .cb             = nfulnl_cb,
1013 };
1014
1015 #ifdef CONFIG_PROC_FS
1016 struct iter_state {
1017         struct seq_net_private p;
1018         unsigned int bucket;
1019 };
1020
1021 static struct hlist_node *get_first(struct net *net, struct iter_state *st)
1022 {
1023         struct nfnl_log_net *log;
1024         if (!st)
1025                 return NULL;
1026
1027         log = nfnl_log_pernet(net);
1028
1029         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
1030                 struct hlist_head *head = &log->instance_table[st->bucket];
1031
1032                 if (!hlist_empty(head))
1033                         return rcu_dereference_bh(hlist_first_rcu(head));
1034         }
1035         return NULL;
1036 }
1037
1038 static struct hlist_node *get_next(struct net *net, struct iter_state *st,
1039                                    struct hlist_node *h)
1040 {
1041         h = rcu_dereference_bh(hlist_next_rcu(h));
1042         while (!h) {
1043                 struct nfnl_log_net *log;
1044                 struct hlist_head *head;
1045
1046                 if (++st->bucket >= INSTANCE_BUCKETS)
1047                         return NULL;
1048
1049                 log = nfnl_log_pernet(net);
1050                 head = &log->instance_table[st->bucket];
1051                 h = rcu_dereference_bh(hlist_first_rcu(head));
1052         }
1053         return h;
1054 }
1055
1056 static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
1057                                   loff_t pos)
1058 {
1059         struct hlist_node *head;
1060         head = get_first(net, st);
1061
1062         if (head)
1063                 while (pos && (head = get_next(net, st, head)))
1064                         pos--;
1065         return pos ? NULL : head;
1066 }
1067
1068 static void *seq_start(struct seq_file *s, loff_t *pos)
1069         __acquires(rcu_bh)
1070 {
1071         rcu_read_lock_bh();
1072         return get_idx(seq_file_net(s), s->private, *pos);
1073 }
1074
1075 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
1076 {
1077         (*pos)++;
1078         return get_next(seq_file_net(s), s->private, v);
1079 }
1080
1081 static void seq_stop(struct seq_file *s, void *v)
1082         __releases(rcu_bh)
1083 {
1084         rcu_read_unlock_bh();
1085 }
1086
1087 static int seq_show(struct seq_file *s, void *v)
1088 {
1089         const struct nfulnl_instance *inst = v;
1090
1091         seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1092                    inst->group_num,
1093                    inst->peer_portid, inst->qlen,
1094                    inst->copy_mode, inst->copy_range,
1095                    inst->flushtimeout, refcount_read(&inst->use));
1096
1097         return 0;
1098 }
1099
1100 static const struct seq_operations nful_seq_ops = {
1101         .start  = seq_start,
1102         .next   = seq_next,
1103         .stop   = seq_stop,
1104         .show   = seq_show,
1105 };
1106 #endif /* PROC_FS */
1107
1108 static int __net_init nfnl_log_net_init(struct net *net)
1109 {
1110         unsigned int i;
1111         struct nfnl_log_net *log = nfnl_log_pernet(net);
1112 #ifdef CONFIG_PROC_FS
1113         struct proc_dir_entry *proc;
1114         kuid_t root_uid;
1115         kgid_t root_gid;
1116 #endif
1117
1118         for (i = 0; i < INSTANCE_BUCKETS; i++)
1119                 INIT_HLIST_HEAD(&log->instance_table[i]);
1120         spin_lock_init(&log->instances_lock);
1121
1122 #ifdef CONFIG_PROC_FS
1123         proc = proc_create_net("nfnetlink_log", 0440, net->nf.proc_netfilter,
1124                         &nful_seq_ops, sizeof(struct iter_state));
1125         if (!proc)
1126                 return -ENOMEM;
1127
1128         root_uid = make_kuid(net->user_ns, 0);
1129         root_gid = make_kgid(net->user_ns, 0);
1130         if (uid_valid(root_uid) && gid_valid(root_gid))
1131                 proc_set_user(proc, root_uid, root_gid);
1132 #endif
1133         return 0;
1134 }
1135
1136 static void __net_exit nfnl_log_net_exit(struct net *net)
1137 {
1138         struct nfnl_log_net *log = nfnl_log_pernet(net);
1139         unsigned int i;
1140
1141 #ifdef CONFIG_PROC_FS
1142         remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1143 #endif
1144         nf_log_unset(net, &nfulnl_logger);
1145         for (i = 0; i < INSTANCE_BUCKETS; i++)
1146                 WARN_ON_ONCE(!hlist_empty(&log->instance_table[i]));
1147 }
1148
1149 static struct pernet_operations nfnl_log_net_ops = {
1150         .init   = nfnl_log_net_init,
1151         .exit   = nfnl_log_net_exit,
1152         .id     = &nfnl_log_net_id,
1153         .size   = sizeof(struct nfnl_log_net),
1154 };
1155
1156 static int __init nfnetlink_log_init(void)
1157 {
1158         int status;
1159
1160         status = register_pernet_subsys(&nfnl_log_net_ops);
1161         if (status < 0) {
1162                 pr_err("failed to register pernet ops\n");
1163                 goto out;
1164         }
1165
1166         netlink_register_notifier(&nfulnl_rtnl_notifier);
1167         status = nfnetlink_subsys_register(&nfulnl_subsys);
1168         if (status < 0) {
1169                 pr_err("failed to create netlink socket\n");
1170                 goto cleanup_netlink_notifier;
1171         }
1172
1173         status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1174         if (status < 0) {
1175                 pr_err("failed to register logger\n");
1176                 goto cleanup_subsys;
1177         }
1178
1179         return status;
1180
1181 cleanup_subsys:
1182         nfnetlink_subsys_unregister(&nfulnl_subsys);
1183 cleanup_netlink_notifier:
1184         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1185         unregister_pernet_subsys(&nfnl_log_net_ops);
1186 out:
1187         return status;
1188 }
1189
1190 static void __exit nfnetlink_log_fini(void)
1191 {
1192         nfnetlink_subsys_unregister(&nfulnl_subsys);
1193         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1194         unregister_pernet_subsys(&nfnl_log_net_ops);
1195         nf_log_unregister(&nfulnl_logger);
1196 }
1197
1198 MODULE_DESCRIPTION("netfilter userspace logging");
1199 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1200 MODULE_LICENSE("GPL");
1201 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1202 MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1203 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1204 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1205 MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */
1206 MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */
1207
1208 module_init(nfnetlink_log_init);
1209 module_exit(nfnetlink_log_fini);