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 #define NFULNL_COPY_DISABLED    0xff
  47 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  48 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  49 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  50 /* max packet size is limited by 16-bit struct nfattr nfa_len field */
  51 #define NFULNL_COPY_RANGE_MAX   (0xFFFF - NLA_HDRLEN)
  52
  53 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  54                                      printk(x, ## args); } while (0);
  55
  56 struct nfulnl_instance {
  57         struct hlist_node hlist;        /* global list of instances */
  58         spinlock_t lock;
  59         refcount_t use;                 /* use count */
  60
  61         unsigned int qlen;              /* number of nlmsgs in skb */
  62         struct sk_buff *skb;            /* pre-allocatd skb */
  63         struct timer_list timer;
  64         struct net *net;
  65         struct user_namespace *peer_user_ns;    /* User namespace of the peer process */
  66         u32 peer_portid;                /* PORTID of the peer process */
  67
  68         /* configurable parameters */
  69         unsigned int flushtimeout;      /* timeout until queue flush */
  70         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  71         unsigned int qthreshold;        /* threshold of the queue */
  72         u_int32_t copy_range;
  73         u_int32_t seq;                  /* instance-local sequential counter */
  74         u_int16_t group_num;            /* number of this queue */
  75         u_int16_t flags;
  76         u_int8_t copy_mode;
  77         struct rcu_head rcu;
  78 };
  79
  80 #define INSTANCE_BUCKETS        16
  81
  82 static unsigned int nfnl_log_net_id __read_mostly;
  83
  84 struct nfnl_log_net {
  85         spinlock_t instances_lock;
  86         struct hlist_head instance_table[INSTANCE_BUCKETS];
  87         atomic_t global_seq;
  88 };
  89
  90 static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
  91 {
  92         return net_generic(net, nfnl_log_net_id);
  93 }
  94
  95 static inline u_int8_t instance_hashfn(u_int16_t group_num)
  96 {
  97         return ((group_num & 0xff) % INSTANCE_BUCKETS);
  98 }
  99
 100 static struct nfulnl_instance *
 101 __instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
 102 {
 103         struct hlist_head *head;
 104         struct nfulnl_instance *inst;
 105
 106         head = &log->instance_table[instance_hashfn(group_num)];
 107         hlist_for_each_entry_rcu(inst, head, hlist) {
 108                 if (inst->group_num == group_num)
 109                         return inst;
 110         }
 111         return NULL;
 112 }
 113
 114 static inline void
 115 instance_get(struct nfulnl_instance *inst)
 116 {
 117         refcount_inc(&inst->use);
 118 }
 119
 120 static struct nfulnl_instance *
 121 instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
 122 {
 123         struct nfulnl_instance *inst;
 124
 125         rcu_read_lock_bh();
 126         inst = __instance_lookup(log, group_num);
 127         if (inst && !refcount_inc_not_zero(&inst->use))
 128                 inst = NULL;
 129         rcu_read_unlock_bh();
 130
 131         return inst;
 132 }
 133
 134 static void nfulnl_instance_free_rcu(struct rcu_head *head)
 135 {
 136         struct nfulnl_instance *inst =
 137                 container_of(head, struct nfulnl_instance, rcu);
 138
 139         put_net(inst->net);
 140         kfree(inst);
 141         module_put(THIS_MODULE);
 142 }
 143
 144 static void
 145 instance_put(struct nfulnl_instance *inst)
 146 {
 147         if (inst && refcount_dec_and_test(&inst->use))
 148                 call_rcu(&inst->rcu, nfulnl_instance_free_rcu);
 149 }
 150
 151 static void nfulnl_timer(struct timer_list *t);
 152
 153 static struct nfulnl_instance *
 154 instance_create(struct net *net, u_int16_t group_num,
 155                 u32 portid, struct user_namespace *user_ns)
 156 {
 157         struct nfulnl_instance *inst;
 158         struct nfnl_log_net *log = nfnl_log_pernet(net);
 159         int err;
 160
 161         spin_lock_bh(&log->instances_lock);
 162         if (__instance_lookup(log, group_num)) {
 163                 err = -EEXIST;
 164                 goto out_unlock;
 165         }
 166
 167         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 168         if (!inst) {
 169                 err = -ENOMEM;
 170                 goto out_unlock;
 171         }
 172
 173         if (!try_module_get(THIS_MODULE)) {
 174                 kfree(inst);
 175                 err = -EAGAIN;
 176                 goto out_unlock;
 177         }
 178
 179         INIT_HLIST_NODE(&inst->hlist);
 180         spin_lock_init(&inst->lock);
 181         /* needs to be two, since we _put() after creation */
 182         refcount_set(&inst->use, 2);
 183
 184         timer_setup(&inst->timer, nfulnl_timer, 0);
 185
 186         inst->net = get_net(net);
 187         inst->peer_user_ns = user_ns;
 188         inst->peer_portid = portid;
 189         inst->group_num = group_num;
 190
 191         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 192         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 193         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 194         inst->copy_mode         = NFULNL_COPY_PACKET;
 195         inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 196
 197         hlist_add_head_rcu(&inst->hlist,
 198                        &log->instance_table[instance_hashfn(group_num)]);
 199
 200
 201         spin_unlock_bh(&log->instances_lock);
 202
 203         return inst;
 204
 205 out_unlock:
 206         spin_unlock_bh(&log->instances_lock);
 207         return ERR_PTR(err);
 208 }
 209
 210 static void __nfulnl_flush(struct nfulnl_instance *inst);
 211
 212 /* called with BH disabled */
 213 static void
 214 __instance_destroy(struct nfulnl_instance *inst)
 215 {
 216         /* first pull it out of the global list */
 217         hlist_del_rcu(&inst->hlist);
 218
 219         /* then flush all pending packets from skb */
 220
 221         spin_lock(&inst->lock);
 222
 223         /* lockless readers wont be able to use us */
 224         inst->copy_mode = NFULNL_COPY_DISABLED;
 225
 226         if (inst->skb)
 227                 __nfulnl_flush(inst);
 228         spin_unlock(&inst->lock);
 229
 230         /* and finally put the refcount */
 231         instance_put(inst);
 232 }
 233
 234 static inline void
 235 instance_destroy(struct nfnl_log_net *log,
 236                  struct nfulnl_instance *inst)
 237 {
 238         spin_lock_bh(&log->instances_lock);
 239         __instance_destroy(inst);
 240         spin_unlock_bh(&log->instances_lock);
 241 }
 242
 243 static int
 244 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 245                   unsigned int range)
 246 {
 247         int status = 0;
 248
 249         spin_lock_bh(&inst->lock);
 250
 251         switch (mode) {
 252         case NFULNL_COPY_NONE:
 253         case NFULNL_COPY_META:
 254                 inst->copy_mode = mode;
 255                 inst->copy_range = 0;
 256                 break;
 257
 258         case NFULNL_COPY_PACKET:
 259                 inst->copy_mode = mode;
 260                 if (range == 0)
 261                         range = NFULNL_COPY_RANGE_MAX;
 262                 inst->copy_range = min_t(unsigned int,
 263                                          range, NFULNL_COPY_RANGE_MAX);
 264                 break;
 265
 266         default:
 267                 status = -EINVAL;
 268                 break;
 269         }
 270
 271         spin_unlock_bh(&inst->lock);
 272
 273         return status;
 274 }
 275
 276 static int
 277 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 278 {
 279         int status;
 280
 281         spin_lock_bh(&inst->lock);
 282         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 283                 status = -ERANGE;
 284         else if (nlbufsiz > 131072)
 285                 status = -ERANGE;
 286         else {
 287                 inst->nlbufsiz = nlbufsiz;
 288                 status = 0;
 289         }
 290         spin_unlock_bh(&inst->lock);
 291
 292         return status;
 293 }
 294
 295 static void
 296 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 297 {
 298         spin_lock_bh(&inst->lock);
 299         inst->flushtimeout = timeout;
 300         spin_unlock_bh(&inst->lock);
 301 }
 302
 303 static void
 304 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 305 {
 306         spin_lock_bh(&inst->lock);
 307         inst->qthreshold = qthresh;
 308         spin_unlock_bh(&inst->lock);
 309 }
 310
 311 static int
 312 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 313 {
 314         spin_lock_bh(&inst->lock);
 315         inst->flags = flags;
 316         spin_unlock_bh(&inst->lock);
 317
 318         return 0;
 319 }
 320
 321 static struct sk_buff *
 322 nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
 323                  unsigned int pkt_size)
 324 {
 325         struct sk_buff *skb;
 326         unsigned int n;
 327
 328         /* alloc skb which should be big enough for a whole multipart
 329          * message.  WARNING: has to be <= 128k due to slab restrictions */
 330
 331         n = max(inst_size, pkt_size);
 332         skb = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN);
 333         if (!skb) {
 334                 if (n > pkt_size) {
 335                         /* try to allocate only as much as we need for current
 336                          * packet */
 337
 338                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
 339                 }
 340         }
 341
 342         return skb;
 343 }
 344
 345 static void
 346 __nfulnl_send(struct nfulnl_instance *inst)
 347 {
 348         if (inst->qlen > 1) {
 349                 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 350                                                  NLMSG_DONE,
 351                                                  sizeof(struct nfgenmsg),
 352                                                  0);
 353                 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
 354                               inst->skb->len, skb_tailroom(inst->skb))) {
 355                         kfree_skb(inst->skb);
 356                         goto out;
 357                 }
 358         }
 359         nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
 360                           MSG_DONTWAIT);
 361 out:
 362         inst->qlen = 0;
 363         inst->skb = NULL;
 364 }
 365
 366 static void
 367 __nfulnl_flush(struct nfulnl_instance *inst)
 368 {
 369         /* timer holds a reference */
 370         if (del_timer(&inst->timer))
 371                 instance_put(inst);
 372         if (inst->skb)
 373                 __nfulnl_send(inst);
 374 }
 375
 376 static void
 377 nfulnl_timer(struct timer_list *t)
 378 {
 379         struct nfulnl_instance *inst = from_timer(inst, t, timer);
 380
 381         spin_lock_bh(&inst->lock);
 382         if (inst->skb)
 383                 __nfulnl_send(inst);
 384         spin_unlock_bh(&inst->lock);
 385         instance_put(inst);
 386 }
 387
 388 static u32 nfulnl_get_bridge_size(const struct sk_buff *skb)
 389 {
 390         u32 size = 0;
 391
 392         if (!skb_mac_header_was_set(skb))
 393                 return 0;
 394
 395         if (skb_vlan_tag_present(skb)) {
 396                 size += nla_total_size(0); /* nested */
 397                 size += nla_total_size(sizeof(u16)); /* id */
 398                 size += nla_total_size(sizeof(u16)); /* tag */
 399         }
 400
 401         if (skb->network_header > skb->mac_header)
 402                 size += nla_total_size(skb->network_header - skb->mac_header);
 403
 404         return size;
 405 }
 406
 407 static int nfulnl_put_bridge(struct nfulnl_instance *inst, const struct sk_buff *skb)
 408 {
 409         if (!skb_mac_header_was_set(skb))
 410                 return 0;
 411
 412         if (skb_vlan_tag_present(skb)) {
 413                 struct nlattr *nest;
 414
 415                 nest = nla_nest_start(inst->skb, NFULA_VLAN);
 416                 if (!nest)
 417                         goto nla_put_failure;
 418
 419                 if (nla_put_be16(inst->skb, NFULA_VLAN_TCI, htons(skb->vlan_tci)) ||
 420                     nla_put_be16(inst->skb, NFULA_VLAN_PROTO, skb->vlan_proto))
 421                         goto nla_put_failure;
 422
 423                 nla_nest_end(inst->skb, nest);
 424         }
 425
 426         if (skb->mac_header < skb->network_header) {
 427                 int len = (int)(skb->network_header - skb->mac_header);
 428
 429                 if (nla_put(inst->skb, NFULA_L2HDR, len, skb_mac_header(skb)))
 430                         goto nla_put_failure;
 431         }
 432
 433         return 0;
 434
 435 nla_put_failure:
 436         return -1;
 437 }
 438
 439 /* This is an inline function, we don't really care about a long
 440  * list of arguments */
 441 static inline int
 442 __build_packet_message(struct nfnl_log_net *log,
 443                         struct nfulnl_instance *inst,
 444                         const struct sk_buff *skb,
 445                         unsigned int data_len,
 446                         u_int8_t pf,
 447                         unsigned int hooknum,
 448                         const struct net_device *indev,
 449                         const struct net_device *outdev,
 450                         const char *prefix, unsigned int plen,
 451                         const struct nfnl_ct_hook *nfnl_ct,
 452                         struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 453 {
 454         struct nfulnl_msg_packet_hdr pmsg;
 455         struct nlmsghdr *nlh;
 456         struct nfgenmsg *nfmsg;
 457         sk_buff_data_t old_tail = inst->skb->tail;
 458         struct sock *sk;
 459         const unsigned char *hwhdrp;
 460
 461         nlh = nlmsg_put(inst->skb, 0, 0,
 462                         nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET),
 463                         sizeof(struct nfgenmsg), 0);
 464         if (!nlh)
 465                 return -1;
 466         nfmsg = nlmsg_data(nlh);
 467         nfmsg->nfgen_family = pf;
 468         nfmsg->version = NFNETLINK_V0;
 469         nfmsg->res_id = htons(inst->group_num);
 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 != skb->network_header) {
 562                 struct nfulnl_msg_packet_hw phw;
 563                 int len;
 564
 565                 memset(&phw, 0, sizeof(phw));
 566                 len = dev_parse_header(skb, phw.hw_addr);
 567                 if (len > 0) {
 568                         phw.hw_addrlen = htons(len);
 569                         if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 570                                 goto nla_put_failure;
 571                 }
 572         }
 573
 574         if (indev && skb_mac_header_was_set(skb)) {
 575                 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 576                     nla_put_be16(inst->skb, NFULA_HWLEN,
 577                                  htons(skb->dev->hard_header_len)))
 578                         goto nla_put_failure;
 579
 580                 hwhdrp = skb_mac_header(skb);
 581
 582                 if (skb->dev->type == ARPHRD_SIT)
 583                         hwhdrp -= ETH_HLEN;
 584
 585                 if (hwhdrp >= skb->head &&
 586                     nla_put(inst->skb, NFULA_HWHEADER,
 587                             skb->dev->hard_header_len, hwhdrp))
 588                         goto nla_put_failure;
 589         }
 590
 591         if (hooknum <= NF_INET_FORWARD && skb->tstamp) {
 592                 struct nfulnl_msg_packet_timestamp ts;
 593                 struct timespec64 kts = ktime_to_timespec64(skb->tstamp);
 594                 ts.sec = cpu_to_be64(kts.tv_sec);
 595                 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
 596
 597                 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 598                         goto nla_put_failure;
 599         }
 600
 601         /* UID */
 602         sk = skb->sk;
 603         if (sk && sk_fullsock(sk)) {
 604                 read_lock_bh(&sk->sk_callback_lock);
 605                 if (sk->sk_socket && sk->sk_socket->file) {
 606                         struct file *file = sk->sk_socket->file;
 607                         const struct cred *cred = file->f_cred;
 608                         struct user_namespace *user_ns = inst->peer_user_ns;
 609                         __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
 610                         __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
 611                         read_unlock_bh(&sk->sk_callback_lock);
 612                         if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 613                             nla_put_be32(inst->skb, NFULA_GID, gid))
 614                                 goto nla_put_failure;
 615                 } else
 616                         read_unlock_bh(&sk->sk_callback_lock);
 617         }
 618
 619         /* local sequence number */
 620         if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 621             nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 622                 goto nla_put_failure;
 623
 624         /* global sequence number */
 625         if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 626             nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 627                          htonl(atomic_inc_return(&log->global_seq))))
 628                 goto nla_put_failure;
 629
 630         if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
 631                                  NFULA_CT, NFULA_CT_INFO) < 0)
 632                 goto nla_put_failure;
 633
 634         if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) &&
 635             nfulnl_put_bridge(inst, skb) < 0)
 636                 goto nla_put_failure;
 637
 638         if (data_len) {
 639                 struct nlattr *nla;
 640                 int size = nla_attr_size(data_len);
 641
 642                 if (skb_tailroom(inst->skb) < nla_total_size(data_len))
 643                         goto nla_put_failure;
 644
 645                 nla = skb_put(inst->skb, nla_total_size(data_len));
 646                 nla->nla_type = NFULA_PAYLOAD;
 647                 nla->nla_len = size;
 648
 649                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 650                         BUG();
 651         }
 652
 653         nlh->nlmsg_len = inst->skb->tail - old_tail;
 654         return 0;
 655
 656 nla_put_failure:
 657         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 658         return -1;
 659 }
 660
 661 static const struct nf_loginfo default_loginfo = {
 662         .type =         NF_LOG_TYPE_ULOG,
 663         .u = {
 664                 .ulog = {
 665                         .copy_len       = 0xffff,
 666                         .group          = 0,
 667                         .qthreshold     = 1,
 668                 },
 669         },
 670 };
 671
 672 /* log handler for internal netfilter logging api */
 673 static void
 674 nfulnl_log_packet(struct net *net,
 675                   u_int8_t pf,
 676                   unsigned int hooknum,
 677                   const struct sk_buff *skb,
 678                   const struct net_device *in,
 679                   const struct net_device *out,
 680                   const struct nf_loginfo *li_user,
 681                   const char *prefix)
 682 {
 683         size_t size;
 684         unsigned int data_len;
 685         struct nfulnl_instance *inst;
 686         const struct nf_loginfo *li;
 687         unsigned int qthreshold;
 688         unsigned int plen = 0;
 689         struct nfnl_log_net *log = nfnl_log_pernet(net);
 690         const struct nfnl_ct_hook *nfnl_ct = NULL;
 691         struct nf_conn *ct = NULL;
 692         enum ip_conntrack_info uninitialized_var(ctinfo);
 693
 694         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 695                 li = li_user;
 696         else
 697                 li = &default_loginfo;
 698
 699         inst = instance_lookup_get(log, li->u.ulog.group);
 700         if (!inst)
 701                 return;
 702
 703         if (prefix)
 704                 plen = strlen(prefix) + 1;
 705
 706         /* FIXME: do we want to make the size calculation conditional based on
 707          * what is actually present?  way more branches and checks, but more
 708          * memory efficient... */
 709         size = nlmsg_total_size(sizeof(struct nfgenmsg))
 710                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 711                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 712                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 713 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 714                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 715                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 716 #endif
 717                 + nla_total_size(sizeof(u_int32_t))     /* mark */
 718                 + nla_total_size(sizeof(u_int32_t))     /* uid */
 719                 + nla_total_size(sizeof(u_int32_t))     /* gid */
 720                 + nla_total_size(plen)                  /* prefix */
 721                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 722                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
 723                 + nla_total_size(sizeof(struct nfgenmsg));      /* NLMSG_DONE */
 724
 725         if (in && skb_mac_header_was_set(skb)) {
 726                 size += nla_total_size(skb->dev->hard_header_len)
 727                         + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 728                         + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 729         }
 730
 731         spin_lock_bh(&inst->lock);
 732
 733         if (inst->flags & NFULNL_CFG_F_SEQ)
 734                 size += nla_total_size(sizeof(u_int32_t));
 735         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 736                 size += nla_total_size(sizeof(u_int32_t));
 737         if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
 738                 nfnl_ct = rcu_dereference(nfnl_ct_hook);
 739                 if (nfnl_ct != NULL) {
 740                         ct = nfnl_ct->get_ct(skb, &ctinfo);
 741                         if (ct != NULL)
 742                                 size += nfnl_ct->build_size(ct);
 743                 }
 744         }
 745         if (pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE)
 746                 size += nfulnl_get_bridge_size(skb);
 747
 748         qthreshold = inst->qthreshold;
 749         /* per-rule qthreshold overrides per-instance */
 750         if (li->u.ulog.qthreshold)
 751                 if (qthreshold > li->u.ulog.qthreshold)
 752                         qthreshold = li->u.ulog.qthreshold;
 753
 754
 755         switch (inst->copy_mode) {
 756         case NFULNL_COPY_META:
 757         case NFULNL_COPY_NONE:
 758                 data_len = 0;
 759                 break;
 760
 761         case NFULNL_COPY_PACKET:
 762                 data_len = inst->copy_range;
 763                 if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) &&
 764                     (li->u.ulog.copy_len < data_len))
 765                         data_len = li->u.ulog.copy_len;
 766
 767                 if (data_len > skb->len)
 768                         data_len = skb->len;
 769
 770                 size += nla_total_size(data_len);
 771                 break;
 772
 773         case NFULNL_COPY_DISABLED:
 774         default:
 775                 goto unlock_and_release;
 776         }
 777
 778         if (inst->skb && size > skb_tailroom(inst->skb)) {
 779                 /* either the queue len is too high or we don't have
 780                  * enough room in the skb left. flush to userspace. */
 781                 __nfulnl_flush(inst);
 782         }
 783
 784         if (!inst->skb) {
 785                 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
 786                                              inst->nlbufsiz, size);
 787                 if (!inst->skb)
 788                         goto alloc_failure;
 789         }
 790
 791         inst->qlen++;
 792
 793         __build_packet_message(log, inst, skb, data_len, pf,
 794                                 hooknum, in, out, prefix, plen,
 795                                 nfnl_ct, ct, ctinfo);
 796
 797         if (inst->qlen >= qthreshold)
 798                 __nfulnl_flush(inst);
 799         /* timer_pending always called within inst->lock, so there
 800          * is no chance of a race here */
 801         else if (!timer_pending(&inst->timer)) {
 802                 instance_get(inst);
 803                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 804                 add_timer(&inst->timer);
 805         }
 806
 807 unlock_and_release:
 808         spin_unlock_bh(&inst->lock);
 809         instance_put(inst);
 810         return;
 811
 812 alloc_failure:
 813         /* FIXME: statistics */
 814         goto unlock_and_release;
 815 }
 816
 817 static int
 818 nfulnl_rcv_nl_event(struct notifier_block *this,
 819                    unsigned long event, void *ptr)
 820 {
 821         struct netlink_notify *n = ptr;
 822         struct nfnl_log_net *log = nfnl_log_pernet(n->net);
 823
 824         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 825                 int i;
 826
 827                 /* destroy all instances for this portid */
 828                 spin_lock_bh(&log->instances_lock);
 829                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 830                         struct hlist_node *t2;
 831                         struct nfulnl_instance *inst;
 832                         struct hlist_head *head = &log->instance_table[i];
 833
 834                         hlist_for_each_entry_safe(inst, t2, head, hlist) {
 835                                 if (n->portid == inst->peer_portid)
 836                                         __instance_destroy(inst);
 837                         }
 838                 }
 839                 spin_unlock_bh(&log->instances_lock);
 840         }
 841         return NOTIFY_DONE;
 842 }
 843
 844 static struct notifier_block nfulnl_rtnl_notifier = {
 845         .notifier_call  = nfulnl_rcv_nl_event,
 846 };
 847
 848 static int nfulnl_recv_unsupp(struct net *net, struct sock *ctnl,
 849                               struct sk_buff *skb, const struct nlmsghdr *nlh,
 850                               const struct nlattr * const nfqa[],
 851                               struct netlink_ext_ack *extack)
 852 {
 853         return -ENOTSUPP;
 854 }
 855
 856 static struct nf_logger nfulnl_logger __read_mostly = {
 857         .name   = "nfnetlink_log",
 858         .type   = NF_LOG_TYPE_ULOG,
 859         .logfn  = nfulnl_log_packet,
 860         .me     = THIS_MODULE,
 861 };
 862
 863 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 864         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 865         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 866         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 867         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 868         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 869         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 870 };
 871
 872 static int nfulnl_recv_config(struct net *net, struct sock *ctnl,
 873                               struct sk_buff *skb, const struct nlmsghdr *nlh,
 874                               const struct nlattr * const nfula[],
 875                               struct netlink_ext_ack *extack)
 876 {
 877         struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 878         u_int16_t group_num = ntohs(nfmsg->res_id);
 879         struct nfulnl_instance *inst;
 880         struct nfulnl_msg_config_cmd *cmd = NULL;
 881         struct nfnl_log_net *log = nfnl_log_pernet(net);
 882         int ret = 0;
 883         u16 flags = 0;
 884
 885         if (nfula[NFULA_CFG_CMD]) {
 886                 u_int8_t pf = nfmsg->nfgen_family;
 887                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
 888
 889                 /* Commands without queue context */
 890                 switch (cmd->command) {
 891                 case NFULNL_CFG_CMD_PF_BIND:
 892                         return nf_log_bind_pf(net, pf, &nfulnl_logger);
 893                 case NFULNL_CFG_CMD_PF_UNBIND:
 894                         nf_log_unbind_pf(net, pf);
 895                         return 0;
 896                 }
 897         }
 898
 899         inst = instance_lookup_get(log, group_num);
 900         if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
 901                 ret = -EPERM;
 902                 goto out_put;
 903         }
 904
 905         /* Check if we support these flags in first place, dependencies should
 906          * be there too not to break atomicity.
 907          */
 908         if (nfula[NFULA_CFG_FLAGS]) {
 909                 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
 910
 911                 if ((flags & NFULNL_CFG_F_CONNTRACK) &&
 912                     !rcu_access_pointer(nfnl_ct_hook)) {
 913 #ifdef CONFIG_MODULES
 914                         nfnl_unlock(NFNL_SUBSYS_ULOG);
 915                         request_module("ip_conntrack_netlink");
 916                         nfnl_lock(NFNL_SUBSYS_ULOG);
 917                         if (rcu_access_pointer(nfnl_ct_hook)) {
 918                                 ret = -EAGAIN;
 919                                 goto out_put;
 920                         }
 921 #endif
 922                         ret = -EOPNOTSUPP;
 923                         goto out_put;
 924                 }
 925         }
 926
 927         if (cmd != NULL) {
 928                 switch (cmd->command) {
 929                 case NFULNL_CFG_CMD_BIND:
 930                         if (inst) {
 931                                 ret = -EBUSY;
 932                                 goto out_put;
 933                         }
 934
 935                         inst = instance_create(net, group_num,
 936                                                NETLINK_CB(skb).portid,
 937                                                sk_user_ns(NETLINK_CB(skb).sk));
 938                         if (IS_ERR(inst)) {
 939                                 ret = PTR_ERR(inst);
 940                                 goto out;
 941                         }
 942                         break;
 943                 case NFULNL_CFG_CMD_UNBIND:
 944                         if (!inst) {
 945                                 ret = -ENODEV;
 946                                 goto out;
 947                         }
 948
 949                         instance_destroy(log, inst);
 950                         goto out_put;
 951                 default:
 952                         ret = -ENOTSUPP;
 953                         goto out_put;
 954                 }
 955         } else if (!inst) {
 956                 ret = -ENODEV;
 957                 goto out;
 958         }
 959
 960         if (nfula[NFULA_CFG_MODE]) {
 961                 struct nfulnl_msg_config_mode *params =
 962                         nla_data(nfula[NFULA_CFG_MODE]);
 963
 964                 nfulnl_set_mode(inst, params->copy_mode,
 965                                 ntohl(params->copy_range));
 966         }
 967
 968         if (nfula[NFULA_CFG_TIMEOUT]) {
 969                 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 970
 971                 nfulnl_set_timeout(inst, ntohl(timeout));
 972         }
 973
 974         if (nfula[NFULA_CFG_NLBUFSIZ]) {
 975                 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 976
 977                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 978         }
 979
 980         if (nfula[NFULA_CFG_QTHRESH]) {
 981                 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 982
 983                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 984         }
 985
 986         if (nfula[NFULA_CFG_FLAGS])
 987                 nfulnl_set_flags(inst, flags);
 988
 989 out_put:
 990         instance_put(inst);
 991 out:
 992         return ret;
 993 }
 994
 995 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 996         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 997                                     .attr_count = NFULA_MAX, },
 998         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 999                                     .attr_count = NFULA_CFG_MAX,
1000                                     .policy = nfula_cfg_policy },
1001 };
1002
1003 static const struct nfnetlink_subsystem nfulnl_subsys = {
1004         .name           = "log",
1005         .subsys_id      = NFNL_SUBSYS_ULOG,
1006         .cb_count       = NFULNL_MSG_MAX,
1007         .cb             = nfulnl_cb,
1008 };
1009
1010 #ifdef CONFIG_PROC_FS
1011 struct iter_state {
1012         struct seq_net_private p;
1013         unsigned int bucket;
1014 };
1015
1016 static struct hlist_node *get_first(struct net *net, struct iter_state *st)
1017 {
1018         struct nfnl_log_net *log;
1019         if (!st)
1020                 return NULL;
1021
1022         log = nfnl_log_pernet(net);
1023
1024         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
1025                 struct hlist_head *head = &log->instance_table[st->bucket];
1026
1027                 if (!hlist_empty(head))
1028                         return rcu_dereference_bh(hlist_first_rcu(head));
1029         }
1030         return NULL;
1031 }
1032
1033 static struct hlist_node *get_next(struct net *net, struct iter_state *st,
1034                                    struct hlist_node *h)
1035 {
1036         h = rcu_dereference_bh(hlist_next_rcu(h));
1037         while (!h) {
1038                 struct nfnl_log_net *log;
1039                 struct hlist_head *head;
1040
1041                 if (++st->bucket >= INSTANCE_BUCKETS)
1042                         return NULL;
1043
1044                 log = nfnl_log_pernet(net);
1045                 head = &log->instance_table[st->bucket];
1046                 h = rcu_dereference_bh(hlist_first_rcu(head));
1047         }
1048         return h;
1049 }
1050
1051 static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
1052                                   loff_t pos)
1053 {
1054         struct hlist_node *head;
1055         head = get_first(net, st);
1056
1057         if (head)
1058                 while (pos && (head = get_next(net, st, head)))
1059                         pos--;
1060         return pos ? NULL : head;
1061 }
1062
1063 static void *seq_start(struct seq_file *s, loff_t *pos)
1064         __acquires(rcu_bh)
1065 {
1066         rcu_read_lock_bh();
1067         return get_idx(seq_file_net(s), s->private, *pos);
1068 }
1069
1070 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
1071 {
1072         (*pos)++;
1073         return get_next(seq_file_net(s), s->private, v);
1074 }
1075
1076 static void seq_stop(struct seq_file *s, void *v)
1077         __releases(rcu_bh)
1078 {
1079         rcu_read_unlock_bh();
1080 }
1081
1082 static int seq_show(struct seq_file *s, void *v)
1083 {
1084         const struct nfulnl_instance *inst = v;
1085
1086         seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1087                    inst->group_num,
1088                    inst->peer_portid, inst->qlen,
1089                    inst->copy_mode, inst->copy_range,
1090                    inst->flushtimeout, refcount_read(&inst->use));
1091
1092         return 0;
1093 }
1094
1095 static const struct seq_operations nful_seq_ops = {
1096         .start  = seq_start,
1097         .next   = seq_next,
1098         .stop   = seq_stop,
1099         .show   = seq_show,
1100 };
1101 #endif /* PROC_FS */
1102
1103 static int __net_init nfnl_log_net_init(struct net *net)
1104 {
1105         unsigned int i;
1106         struct nfnl_log_net *log = nfnl_log_pernet(net);
1107 #ifdef CONFIG_PROC_FS
1108         struct proc_dir_entry *proc;
1109         kuid_t root_uid;
1110         kgid_t root_gid;
1111 #endif
1112
1113         for (i = 0; i < INSTANCE_BUCKETS; i++)
1114                 INIT_HLIST_HEAD(&log->instance_table[i]);
1115         spin_lock_init(&log->instances_lock);
1116
1117 #ifdef CONFIG_PROC_FS
1118         proc = proc_create_net("nfnetlink_log", 0440, net->nf.proc_netfilter,
1119                         &nful_seq_ops, sizeof(struct iter_state));
1120         if (!proc)
1121                 return -ENOMEM;
1122
1123         root_uid = make_kuid(net->user_ns, 0);
1124         root_gid = make_kgid(net->user_ns, 0);
1125         if (uid_valid(root_uid) && gid_valid(root_gid))
1126                 proc_set_user(proc, root_uid, root_gid);
1127 #endif
1128         return 0;
1129 }
1130
1131 static void __net_exit nfnl_log_net_exit(struct net *net)
1132 {
1133         struct nfnl_log_net *log = nfnl_log_pernet(net);
1134         unsigned int i;
1135
1136 #ifdef CONFIG_PROC_FS
1137         remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1138 #endif
1139         nf_log_unset(net, &nfulnl_logger);
1140         for (i = 0; i < INSTANCE_BUCKETS; i++)
1141                 WARN_ON_ONCE(!hlist_empty(&log->instance_table[i]));
1142 }
1143
1144 static struct pernet_operations nfnl_log_net_ops = {
1145         .init   = nfnl_log_net_init,
1146         .exit   = nfnl_log_net_exit,
1147         .id     = &nfnl_log_net_id,
1148         .size   = sizeof(struct nfnl_log_net),
1149 };
1150
1151 static int __init nfnetlink_log_init(void)
1152 {
1153         int status;
1154
1155         status = register_pernet_subsys(&nfnl_log_net_ops);
1156         if (status < 0) {
1157                 pr_err("failed to register pernet ops\n");
1158                 goto out;
1159         }
1160
1161         netlink_register_notifier(&nfulnl_rtnl_notifier);
1162         status = nfnetlink_subsys_register(&nfulnl_subsys);
1163         if (status < 0) {
1164                 pr_err("failed to create netlink socket\n");
1165                 goto cleanup_netlink_notifier;
1166         }
1167
1168         status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1169         if (status < 0) {
1170                 pr_err("failed to register logger\n");
1171                 goto cleanup_subsys;
1172         }
1173
1174         return status;
1175
1176 cleanup_subsys:
1177         nfnetlink_subsys_unregister(&nfulnl_subsys);
1178 cleanup_netlink_notifier:
1179         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1180         unregister_pernet_subsys(&nfnl_log_net_ops);
1181 out:
1182         return status;
1183 }
1184
1185 static void __exit nfnetlink_log_fini(void)
1186 {
1187         nfnetlink_subsys_unregister(&nfulnl_subsys);
1188         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1189         unregister_pernet_subsys(&nfnl_log_net_ops);
1190         nf_log_unregister(&nfulnl_logger);
1191 }
1192
1193 MODULE_DESCRIPTION("netfilter userspace logging");
1194 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1195 MODULE_LICENSE("GPL");
1196 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1197 MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1198 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1199 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1200 MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */
1201 MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */
1202
1203 module_init(nfnetlink_log_init);
1204 module_exit(nfnetlink_log_fini);