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 #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 <net/netlink.h>
  24 #include <linux/netfilter/nfnetlink.h>
  25 #include <linux/netfilter/nfnetlink_log.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/proc_fs.h>
  29 #include <linux/security.h>
  30 #include <linux/list.h>
  31 #include <linux/slab.h>
  32 #include <net/sock.h>
  33 #include <net/netfilter/nf_log.h>
  34 #include <net/netns/generic.h>
  35 #include <net/netfilter/nfnetlink_log.h>
  36
  37 #include <linux/atomic.h>
  38
  39 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
  40 #include "../bridge/br_private.h"
  41 #endif
  42
  43 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  44 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  45 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  46 /* max packet size is limited by 16-bit struct nfattr nfa_len field */
  47 #define NFULNL_COPY_RANGE_MAX   (0xFFFF - NLA_HDRLEN)
  48
  49 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  50                                      printk(x, ## args); } while (0);
  51
  52 struct nfulnl_instance {
  53         struct hlist_node hlist;        /* global list of instances */
  54         spinlock_t lock;
  55         atomic_t use;                   /* use count */
  56
  57         unsigned int qlen;              /* number of nlmsgs in skb */
  58         struct sk_buff *skb;            /* pre-allocatd skb */
  59         struct timer_list timer;
  60         struct net *net;
  61         struct user_namespace *peer_user_ns;    /* User namespace of the peer process */
  62         int peer_portid;                        /* PORTID of the peer process */
  63
  64         /* configurable parameters */
  65         unsigned int flushtimeout;      /* timeout until queue flush */
  66         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  67         unsigned int qthreshold;        /* threshold of the queue */
  68         u_int32_t copy_range;
  69         u_int32_t seq;                  /* instance-local sequential counter */
  70         u_int16_t group_num;            /* number of this queue */
  71         u_int16_t flags;
  72         u_int8_t copy_mode;
  73         struct rcu_head rcu;
  74 };
  75
  76 #define INSTANCE_BUCKETS        16
  77
  78 static int nfnl_log_net_id __read_mostly;
  79
  80 struct nfnl_log_net {
  81         spinlock_t instances_lock;
  82         struct hlist_head instance_table[INSTANCE_BUCKETS];
  83         atomic_t global_seq;
  84 };
  85
  86 static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
  87 {
  88         return net_generic(net, nfnl_log_net_id);
  89 }
  90
  91 static inline u_int8_t instance_hashfn(u_int16_t group_num)
  92 {
  93         return ((group_num & 0xff) % INSTANCE_BUCKETS);
  94 }
  95
  96 static struct nfulnl_instance *
  97 __instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
  98 {
  99         struct hlist_head *head;
 100         struct nfulnl_instance *inst;
 101
 102         head = &log->instance_table[instance_hashfn(group_num)];
 103         hlist_for_each_entry_rcu(inst, head, hlist) {
 104                 if (inst->group_num == group_num)
 105                         return inst;
 106         }
 107         return NULL;
 108 }
 109
 110 static inline void
 111 instance_get(struct nfulnl_instance *inst)
 112 {
 113         atomic_inc(&inst->use);
 114 }
 115
 116 static struct nfulnl_instance *
 117 instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
 118 {
 119         struct nfulnl_instance *inst;
 120
 121         rcu_read_lock_bh();
 122         inst = __instance_lookup(log, group_num);
 123         if (inst && !atomic_inc_not_zero(&inst->use))
 124                 inst = NULL;
 125         rcu_read_unlock_bh();
 126
 127         return inst;
 128 }
 129
 130 static void nfulnl_instance_free_rcu(struct rcu_head *head)
 131 {
 132         struct nfulnl_instance *inst =
 133                 container_of(head, struct nfulnl_instance, rcu);
 134
 135         put_net(inst->net);
 136         kfree(inst);
 137         module_put(THIS_MODULE);
 138 }
 139
 140 static void
 141 instance_put(struct nfulnl_instance *inst)
 142 {
 143         if (inst && atomic_dec_and_test(&inst->use))
 144                 call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
 145 }
 146
 147 static void nfulnl_timer(unsigned long data);
 148
 149 static struct nfulnl_instance *
 150 instance_create(struct net *net, u_int16_t group_num,
 151                 int portid, struct user_namespace *user_ns)
 152 {
 153         struct nfulnl_instance *inst;
 154         struct nfnl_log_net *log = nfnl_log_pernet(net);
 155         int err;
 156
 157         spin_lock_bh(&log->instances_lock);
 158         if (__instance_lookup(log, group_num)) {
 159                 err = -EEXIST;
 160                 goto out_unlock;
 161         }
 162
 163         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 164         if (!inst) {
 165                 err = -ENOMEM;
 166                 goto out_unlock;
 167         }
 168
 169         if (!try_module_get(THIS_MODULE)) {
 170                 kfree(inst);
 171                 err = -EAGAIN;
 172                 goto out_unlock;
 173         }
 174
 175         INIT_HLIST_NODE(&inst->hlist);
 176         spin_lock_init(&inst->lock);
 177         /* needs to be two, since we _put() after creation */
 178         atomic_set(&inst->use, 2);
 179
 180         setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
 181
 182         inst->net = get_net(net);
 183         inst->peer_user_ns = user_ns;
 184         inst->peer_portid = portid;
 185         inst->group_num = group_num;
 186
 187         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 188         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 189         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 190         inst->copy_mode         = NFULNL_COPY_PACKET;
 191         inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 192
 193         hlist_add_head_rcu(&inst->hlist,
 194                        &log->instance_table[instance_hashfn(group_num)]);
 195
 196
 197         spin_unlock_bh(&log->instances_lock);
 198
 199         return inst;
 200
 201 out_unlock:
 202         spin_unlock_bh(&log->instances_lock);
 203         return ERR_PTR(err);
 204 }
 205
 206 static void __nfulnl_flush(struct nfulnl_instance *inst);
 207
 208 /* called with BH disabled */
 209 static void
 210 __instance_destroy(struct nfulnl_instance *inst)
 211 {
 212         /* first pull it out of the global list */
 213         hlist_del_rcu(&inst->hlist);
 214
 215         /* then flush all pending packets from skb */
 216
 217         spin_lock(&inst->lock);
 218
 219         /* lockless readers wont be able to use us */
 220         inst->copy_mode = NFULNL_COPY_DISABLED;
 221
 222         if (inst->skb)
 223                 __nfulnl_flush(inst);
 224         spin_unlock(&inst->lock);
 225
 226         /* and finally put the refcount */
 227         instance_put(inst);
 228 }
 229
 230 static inline void
 231 instance_destroy(struct nfnl_log_net *log,
 232                  struct nfulnl_instance *inst)
 233 {
 234         spin_lock_bh(&log->instances_lock);
 235         __instance_destroy(inst);
 236         spin_unlock_bh(&log->instances_lock);
 237 }
 238
 239 static int
 240 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 241                   unsigned int range)
 242 {
 243         int status = 0;
 244
 245         spin_lock_bh(&inst->lock);
 246
 247         switch (mode) {
 248         case NFULNL_COPY_NONE:
 249         case NFULNL_COPY_META:
 250                 inst->copy_mode = mode;
 251                 inst->copy_range = 0;
 252                 break;
 253
 254         case NFULNL_COPY_PACKET:
 255                 inst->copy_mode = mode;
 256                 if (range == 0)
 257                         range = NFULNL_COPY_RANGE_MAX;
 258                 inst->copy_range = min_t(unsigned int,
 259                                          range, NFULNL_COPY_RANGE_MAX);
 260                 break;
 261
 262         default:
 263                 status = -EINVAL;
 264                 break;
 265         }
 266
 267         spin_unlock_bh(&inst->lock);
 268
 269         return status;
 270 }
 271
 272 static int
 273 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 274 {
 275         int status;
 276
 277         spin_lock_bh(&inst->lock);
 278         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 279                 status = -ERANGE;
 280         else if (nlbufsiz > 131072)
 281                 status = -ERANGE;
 282         else {
 283                 inst->nlbufsiz = nlbufsiz;
 284                 status = 0;
 285         }
 286         spin_unlock_bh(&inst->lock);
 287
 288         return status;
 289 }
 290
 291 static int
 292 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 293 {
 294         spin_lock_bh(&inst->lock);
 295         inst->flushtimeout = timeout;
 296         spin_unlock_bh(&inst->lock);
 297
 298         return 0;
 299 }
 300
 301 static int
 302 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 303 {
 304         spin_lock_bh(&inst->lock);
 305         inst->qthreshold = qthresh;
 306         spin_unlock_bh(&inst->lock);
 307
 308         return 0;
 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 = nfnetlink_alloc_skb(net, n, peer_portid, GFP_ATOMIC);
 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 = nfnetlink_alloc_skb(net, pkt_size,
 339                                                   peer_portid, GFP_ATOMIC);
 340                         if (!skb)
 341                                 pr_err("nfnetlink_log: can't even alloc %u bytes\n",
 342                                        pkt_size);
 343                 }
 344         }
 345
 346         return skb;
 347 }
 348
 349 static void
 350 __nfulnl_send(struct nfulnl_instance *inst)
 351 {
 352         if (inst->qlen > 1) {
 353                 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 354                                                  NLMSG_DONE,
 355                                                  sizeof(struct nfgenmsg),
 356                                                  0);
 357                 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
 358                               inst->skb->len, skb_tailroom(inst->skb))) {
 359                         kfree_skb(inst->skb);
 360                         goto out;
 361                 }
 362         }
 363         nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
 364                           MSG_DONTWAIT);
 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(unsigned long data)
 382 {
 383         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 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 /* This is an inline function, we don't really care about a long
 393  * list of arguments */
 394 static inline int
 395 __build_packet_message(struct nfnl_log_net *log,
 396                         struct nfulnl_instance *inst,
 397                         const struct sk_buff *skb,
 398                         unsigned int data_len,
 399                         u_int8_t pf,
 400                         unsigned int hooknum,
 401                         const struct net_device *indev,
 402                         const struct net_device *outdev,
 403                         const char *prefix, unsigned int plen)
 404 {
 405         struct nfulnl_msg_packet_hdr pmsg;
 406         struct nlmsghdr *nlh;
 407         struct nfgenmsg *nfmsg;
 408         sk_buff_data_t old_tail = inst->skb->tail;
 409         struct sock *sk;
 410         const unsigned char *hwhdrp;
 411
 412         nlh = nlmsg_put(inst->skb, 0, 0,
 413                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 414                         sizeof(struct nfgenmsg), 0);
 415         if (!nlh)
 416                 return -1;
 417         nfmsg = nlmsg_data(nlh);
 418         nfmsg->nfgen_family = pf;
 419         nfmsg->version = NFNETLINK_V0;
 420         nfmsg->res_id = htons(inst->group_num);
 421
 422         memset(&pmsg, 0, sizeof(pmsg));
 423         pmsg.hw_protocol        = skb->protocol;
 424         pmsg.hook               = hooknum;
 425
 426         if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
 427                 goto nla_put_failure;
 428
 429         if (prefix &&
 430             nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
 431                 goto nla_put_failure;
 432
 433         if (indev) {
 434 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 435                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 436                                  htonl(indev->ifindex)))
 437                         goto nla_put_failure;
 438 #else
 439                 if (pf == PF_BRIDGE) {
 440                         /* Case 1: outdev is physical input device, we need to
 441                          * look for bridge group (when called from
 442                          * netfilter_bridge) */
 443                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 444                                          htonl(indev->ifindex)) ||
 445                         /* this is the bridge group "brX" */
 446                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 447                             nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 448                                          htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 449                                 goto nla_put_failure;
 450                 } else {
 451                         /* Case 2: indev is bridge group, we need to look for
 452                          * physical device (when called from ipv4) */
 453                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 454                                          htonl(indev->ifindex)))
 455                                 goto nla_put_failure;
 456                         if (skb->nf_bridge && skb->nf_bridge->physindev &&
 457                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 458                                          htonl(skb->nf_bridge->physindev->ifindex)))
 459                                 goto nla_put_failure;
 460                 }
 461 #endif
 462         }
 463
 464         if (outdev) {
 465 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 466                 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 467                                  htonl(outdev->ifindex)))
 468                         goto nla_put_failure;
 469 #else
 470                 if (pf == PF_BRIDGE) {
 471                         /* Case 1: outdev is physical output device, we need to
 472                          * look for bridge group (when called from
 473                          * netfilter_bridge) */
 474                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 475                                          htonl(outdev->ifindex)) ||
 476                         /* this is the bridge group "brX" */
 477                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 478                             nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 479                                          htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 480                                 goto nla_put_failure;
 481                 } else {
 482                         /* Case 2: indev is a bridge group, we need to look
 483                          * for physical device (when called from ipv4) */
 484                         if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 485                                          htonl(outdev->ifindex)))
 486                                 goto nla_put_failure;
 487                         if (skb->nf_bridge && skb->nf_bridge->physoutdev &&
 488                             nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 489                                          htonl(skb->nf_bridge->physoutdev->ifindex)))
 490                                 goto nla_put_failure;
 491                 }
 492 #endif
 493         }
 494
 495         if (skb->mark &&
 496             nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
 497                 goto nla_put_failure;
 498
 499         if (indev && skb->dev &&
 500             skb->mac_header != skb->network_header) {
 501                 struct nfulnl_msg_packet_hw phw;
 502                 int len;
 503
 504                 memset(&phw, 0, sizeof(phw));
 505                 len = dev_parse_header(skb, phw.hw_addr);
 506                 if (len > 0) {
 507                         phw.hw_addrlen = htons(len);
 508                         if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 509                                 goto nla_put_failure;
 510                 }
 511         }
 512
 513         if (indev && skb_mac_header_was_set(skb)) {
 514                 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 515                     nla_put_be16(inst->skb, NFULA_HWLEN,
 516                                  htons(skb->dev->hard_header_len)))
 517                         goto nla_put_failure;
 518
 519                 hwhdrp = skb_mac_header(skb);
 520
 521                 if (skb->dev->type == ARPHRD_SIT)
 522                         hwhdrp -= ETH_HLEN;
 523
 524                 if (hwhdrp >= skb->head &&
 525                     nla_put(inst->skb, NFULA_HWHEADER,
 526                             skb->dev->hard_header_len, hwhdrp))
 527                         goto nla_put_failure;
 528         }
 529
 530         if (skb->tstamp.tv64) {
 531                 struct nfulnl_msg_packet_timestamp ts;
 532                 struct timeval tv = ktime_to_timeval(skb->tstamp);
 533                 ts.sec = cpu_to_be64(tv.tv_sec);
 534                 ts.usec = cpu_to_be64(tv.tv_usec);
 535
 536                 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 537                         goto nla_put_failure;
 538         }
 539
 540         /* UID */
 541         sk = skb->sk;
 542         if (sk && sk->sk_state != TCP_TIME_WAIT) {
 543                 read_lock_bh(&sk->sk_callback_lock);
 544                 if (sk->sk_socket && sk->sk_socket->file) {
 545                         struct file *file = sk->sk_socket->file;
 546                         const struct cred *cred = file->f_cred;
 547                         struct user_namespace *user_ns = inst->peer_user_ns;
 548                         __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
 549                         __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
 550                         read_unlock_bh(&sk->sk_callback_lock);
 551                         if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 552                             nla_put_be32(inst->skb, NFULA_GID, gid))
 553                                 goto nla_put_failure;
 554                 } else
 555                         read_unlock_bh(&sk->sk_callback_lock);
 556         }
 557
 558         /* local sequence number */
 559         if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 560             nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 561                 goto nla_put_failure;
 562
 563         /* global sequence number */
 564         if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 565             nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 566                          htonl(atomic_inc_return(&log->global_seq))))
 567                 goto nla_put_failure;
 568
 569         if (data_len) {
 570                 struct nlattr *nla;
 571                 int size = nla_attr_size(data_len);
 572
 573                 if (skb_tailroom(inst->skb) < nla_total_size(data_len)) {
 574                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 575                         return -1;
 576                 }
 577
 578                 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
 579                 nla->nla_type = NFULA_PAYLOAD;
 580                 nla->nla_len = size;
 581
 582                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 583                         BUG();
 584         }
 585
 586         nlh->nlmsg_len = inst->skb->tail - old_tail;
 587         return 0;
 588
 589 nla_put_failure:
 590         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 591         return -1;
 592 }
 593
 594 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 595
 596 static struct nf_loginfo default_loginfo = {
 597         .type =         NF_LOG_TYPE_ULOG,
 598         .u = {
 599                 .ulog = {
 600                         .copy_len       = 0xffff,
 601                         .group          = 0,
 602                         .qthreshold     = 1,
 603                 },
 604         },
 605 };
 606
 607 /* log handler for internal netfilter logging api */
 608 void
 609 nfulnl_log_packet(struct net *net,
 610                   u_int8_t pf,
 611                   unsigned int hooknum,
 612                   const struct sk_buff *skb,
 613                   const struct net_device *in,
 614                   const struct net_device *out,
 615                   const struct nf_loginfo *li_user,
 616                   const char *prefix)
 617 {
 618         unsigned int size, data_len;
 619         struct nfulnl_instance *inst;
 620         const struct nf_loginfo *li;
 621         unsigned int qthreshold;
 622         unsigned int plen;
 623         struct nfnl_log_net *log = nfnl_log_pernet(net);
 624
 625         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 626                 li = li_user;
 627         else
 628                 li = &default_loginfo;
 629
 630         inst = instance_lookup_get(log, li->u.ulog.group);
 631         if (!inst)
 632                 return;
 633
 634         plen = 0;
 635         if (prefix)
 636                 plen = strlen(prefix) + 1;
 637
 638         /* FIXME: do we want to make the size calculation conditional based on
 639          * what is actually present?  way more branches and checks, but more
 640          * memory efficient... */
 641         size =    nlmsg_total_size(sizeof(struct nfgenmsg))
 642                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 643                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 644                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 645 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 646                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 647                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 648 #endif
 649                 + nla_total_size(sizeof(u_int32_t))     /* mark */
 650                 + nla_total_size(sizeof(u_int32_t))     /* uid */
 651                 + nla_total_size(sizeof(u_int32_t))     /* gid */
 652                 + nla_total_size(plen)                  /* prefix */
 653                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 654                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
 655                 + nla_total_size(sizeof(struct nfgenmsg));      /* NLMSG_DONE */
 656
 657         if (in && skb_mac_header_was_set(skb)) {
 658                 size +=   nla_total_size(skb->dev->hard_header_len)
 659                         + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 660                         + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 661         }
 662
 663         spin_lock_bh(&inst->lock);
 664
 665         if (inst->flags & NFULNL_CFG_F_SEQ)
 666                 size += nla_total_size(sizeof(u_int32_t));
 667         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 668                 size += nla_total_size(sizeof(u_int32_t));
 669
 670         qthreshold = inst->qthreshold;
 671         /* per-rule qthreshold overrides per-instance */
 672         if (li->u.ulog.qthreshold)
 673                 if (qthreshold > li->u.ulog.qthreshold)
 674                         qthreshold = li->u.ulog.qthreshold;
 675
 676
 677         switch (inst->copy_mode) {
 678         case NFULNL_COPY_META:
 679         case NFULNL_COPY_NONE:
 680                 data_len = 0;
 681                 break;
 682
 683         case NFULNL_COPY_PACKET:
 684                 if (inst->copy_range > skb->len)
 685                         data_len = skb->len;
 686                 else
 687                         data_len = inst->copy_range;
 688
 689                 size += nla_total_size(data_len);
 690                 break;
 691
 692         case NFULNL_COPY_DISABLED:
 693         default:
 694                 goto unlock_and_release;
 695         }
 696
 697         if (inst->skb && size > skb_tailroom(inst->skb)) {
 698                 /* either the queue len is too high or we don't have
 699                  * enough room in the skb left. flush to userspace. */
 700                 __nfulnl_flush(inst);
 701         }
 702
 703         if (!inst->skb) {
 704                 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
 705                                              inst->nlbufsiz, size);
 706                 if (!inst->skb)
 707                         goto alloc_failure;
 708         }
 709
 710         inst->qlen++;
 711
 712         __build_packet_message(log, inst, skb, data_len, pf,
 713                                 hooknum, in, out, prefix, plen);
 714
 715         if (inst->qlen >= qthreshold)
 716                 __nfulnl_flush(inst);
 717         /* timer_pending always called within inst->lock, so there
 718          * is no chance of a race here */
 719         else if (!timer_pending(&inst->timer)) {
 720                 instance_get(inst);
 721                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 722                 add_timer(&inst->timer);
 723         }
 724
 725 unlock_and_release:
 726         spin_unlock_bh(&inst->lock);
 727         instance_put(inst);
 728         return;
 729
 730 alloc_failure:
 731         /* FIXME: statistics */
 732         goto unlock_and_release;
 733 }
 734 EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 735
 736 static int
 737 nfulnl_rcv_nl_event(struct notifier_block *this,
 738                    unsigned long event, void *ptr)
 739 {
 740         struct netlink_notify *n = ptr;
 741         struct nfnl_log_net *log = nfnl_log_pernet(n->net);
 742
 743         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 744                 int i;
 745
 746                 /* destroy all instances for this portid */
 747                 spin_lock_bh(&log->instances_lock);
 748                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 749                         struct hlist_node *t2;
 750                         struct nfulnl_instance *inst;
 751                         struct hlist_head *head = &log->instance_table[i];
 752
 753                         hlist_for_each_entry_safe(inst, t2, head, hlist) {
 754                                 if (n->portid == inst->peer_portid)
 755                                         __instance_destroy(inst);
 756                         }
 757                 }
 758                 spin_unlock_bh(&log->instances_lock);
 759         }
 760         return NOTIFY_DONE;
 761 }
 762
 763 static struct notifier_block nfulnl_rtnl_notifier = {
 764         .notifier_call  = nfulnl_rcv_nl_event,
 765 };
 766
 767 static int
 768 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 769                    const struct nlmsghdr *nlh,
 770                    const struct nlattr * const nfqa[])
 771 {
 772         return -ENOTSUPP;
 773 }
 774
 775 static struct nf_logger nfulnl_logger __read_mostly = {
 776         .name   = "nfnetlink_log",
 777         .type   = NF_LOG_TYPE_ULOG,
 778         .logfn  = &nfulnl_log_packet,
 779         .me     = THIS_MODULE,
 780 };
 781
 782 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 783         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 784         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 785         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 786         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 787         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 788         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 789 };
 790
 791 static int
 792 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 793                    const struct nlmsghdr *nlh,
 794                    const struct nlattr * const nfula[])
 795 {
 796         struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 797         u_int16_t group_num = ntohs(nfmsg->res_id);
 798         struct nfulnl_instance *inst;
 799         struct nfulnl_msg_config_cmd *cmd = NULL;
 800         struct net *net = sock_net(ctnl);
 801         struct nfnl_log_net *log = nfnl_log_pernet(net);
 802         int ret = 0;
 803
 804         if (nfula[NFULA_CFG_CMD]) {
 805                 u_int8_t pf = nfmsg->nfgen_family;
 806                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
 807
 808                 /* Commands without queue context */
 809                 switch (cmd->command) {
 810                 case NFULNL_CFG_CMD_PF_BIND:
 811                         return nf_log_bind_pf(net, pf, &nfulnl_logger);
 812                 case NFULNL_CFG_CMD_PF_UNBIND:
 813                         nf_log_unbind_pf(net, pf);
 814                         return 0;
 815                 }
 816         }
 817
 818         inst = instance_lookup_get(log, group_num);
 819         if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
 820                 ret = -EPERM;
 821                 goto out_put;
 822         }
 823
 824         if (cmd != NULL) {
 825                 switch (cmd->command) {
 826                 case NFULNL_CFG_CMD_BIND:
 827                         if (inst) {
 828                                 ret = -EBUSY;
 829                                 goto out_put;
 830                         }
 831
 832                         inst = instance_create(net, group_num,
 833                                                NETLINK_CB(skb).portid,
 834                                                sk_user_ns(NETLINK_CB(skb).sk));
 835                         if (IS_ERR(inst)) {
 836                                 ret = PTR_ERR(inst);
 837                                 goto out;
 838                         }
 839                         break;
 840                 case NFULNL_CFG_CMD_UNBIND:
 841                         if (!inst) {
 842                                 ret = -ENODEV;
 843                                 goto out;
 844                         }
 845
 846                         instance_destroy(log, inst);
 847                         goto out_put;
 848                 default:
 849                         ret = -ENOTSUPP;
 850                         break;
 851                 }
 852         }
 853
 854         if (nfula[NFULA_CFG_MODE]) {
 855                 struct nfulnl_msg_config_mode *params;
 856                 params = nla_data(nfula[NFULA_CFG_MODE]);
 857
 858                 if (!inst) {
 859                         ret = -ENODEV;
 860                         goto out;
 861                 }
 862                 nfulnl_set_mode(inst, params->copy_mode,
 863                                 ntohl(params->copy_range));
 864         }
 865
 866         if (nfula[NFULA_CFG_TIMEOUT]) {
 867                 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 868
 869                 if (!inst) {
 870                         ret = -ENODEV;
 871                         goto out;
 872                 }
 873                 nfulnl_set_timeout(inst, ntohl(timeout));
 874         }
 875
 876         if (nfula[NFULA_CFG_NLBUFSIZ]) {
 877                 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 878
 879                 if (!inst) {
 880                         ret = -ENODEV;
 881                         goto out;
 882                 }
 883                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 884         }
 885
 886         if (nfula[NFULA_CFG_QTHRESH]) {
 887                 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 888
 889                 if (!inst) {
 890                         ret = -ENODEV;
 891                         goto out;
 892                 }
 893                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 894         }
 895
 896         if (nfula[NFULA_CFG_FLAGS]) {
 897                 __be16 flags = nla_get_be16(nfula[NFULA_CFG_FLAGS]);
 898
 899                 if (!inst) {
 900                         ret = -ENODEV;
 901                         goto out;
 902                 }
 903                 nfulnl_set_flags(inst, ntohs(flags));
 904         }
 905
 906 out_put:
 907         instance_put(inst);
 908 out:
 909         return ret;
 910 }
 911
 912 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 913         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 914                                     .attr_count = NFULA_MAX, },
 915         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 916                                     .attr_count = NFULA_CFG_MAX,
 917                                     .policy = nfula_cfg_policy },
 918 };
 919
 920 static const struct nfnetlink_subsystem nfulnl_subsys = {
 921         .name           = "log",
 922         .subsys_id      = NFNL_SUBSYS_ULOG,
 923         .cb_count       = NFULNL_MSG_MAX,
 924         .cb             = nfulnl_cb,
 925 };
 926
 927 #ifdef CONFIG_PROC_FS
 928 struct iter_state {
 929         struct seq_net_private p;
 930         unsigned int bucket;
 931 };
 932
 933 static struct hlist_node *get_first(struct net *net, struct iter_state *st)
 934 {
 935         struct nfnl_log_net *log;
 936         if (!st)
 937                 return NULL;
 938
 939         log = nfnl_log_pernet(net);
 940
 941         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 942                 struct hlist_head *head = &log->instance_table[st->bucket];
 943
 944                 if (!hlist_empty(head))
 945                         return rcu_dereference_bh(hlist_first_rcu(head));
 946         }
 947         return NULL;
 948 }
 949
 950 static struct hlist_node *get_next(struct net *net, struct iter_state *st,
 951                                    struct hlist_node *h)
 952 {
 953         h = rcu_dereference_bh(hlist_next_rcu(h));
 954         while (!h) {
 955                 struct nfnl_log_net *log;
 956                 struct hlist_head *head;
 957
 958                 if (++st->bucket >= INSTANCE_BUCKETS)
 959                         return NULL;
 960
 961                 log = nfnl_log_pernet(net);
 962                 head = &log->instance_table[st->bucket];
 963                 h = rcu_dereference_bh(hlist_first_rcu(head));
 964         }
 965         return h;
 966 }
 967
 968 static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
 969                                   loff_t pos)
 970 {
 971         struct hlist_node *head;
 972         head = get_first(net, st);
 973
 974         if (head)
 975                 while (pos && (head = get_next(net, st, head)))
 976                         pos--;
 977         return pos ? NULL : head;
 978 }
 979
 980 static void *seq_start(struct seq_file *s, loff_t *pos)
 981         __acquires(rcu_bh)
 982 {
 983         rcu_read_lock_bh();
 984         return get_idx(seq_file_net(s), s->private, *pos);
 985 }
 986
 987 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 988 {
 989         (*pos)++;
 990         return get_next(seq_file_net(s), s->private, v);
 991 }
 992
 993 static void seq_stop(struct seq_file *s, void *v)
 994         __releases(rcu_bh)
 995 {
 996         rcu_read_unlock_bh();
 997 }
 998
 999 static int seq_show(struct seq_file *s, void *v)
1000 {
1001         const struct nfulnl_instance *inst = v;
1002
1003         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
1004                           inst->group_num,
1005                           inst->peer_portid, inst->qlen,
1006                           inst->copy_mode, inst->copy_range,
1007                           inst->flushtimeout, atomic_read(&inst->use));
1008 }
1009
1010 static const struct seq_operations nful_seq_ops = {
1011         .start  = seq_start,
1012         .next   = seq_next,
1013         .stop   = seq_stop,
1014         .show   = seq_show,
1015 };
1016
1017 static int nful_open(struct inode *inode, struct file *file)
1018 {
1019         return seq_open_net(inode, file, &nful_seq_ops,
1020                             sizeof(struct iter_state));
1021 }
1022
1023 static const struct file_operations nful_file_ops = {
1024         .owner   = THIS_MODULE,
1025         .open    = nful_open,
1026         .read    = seq_read,
1027         .llseek  = seq_lseek,
1028         .release = seq_release_net,
1029 };
1030
1031 #endif /* PROC_FS */
1032
1033 static int __net_init nfnl_log_net_init(struct net *net)
1034 {
1035         unsigned int i;
1036         struct nfnl_log_net *log = nfnl_log_pernet(net);
1037
1038         for (i = 0; i < INSTANCE_BUCKETS; i++)
1039                 INIT_HLIST_HEAD(&log->instance_table[i]);
1040         spin_lock_init(&log->instances_lock);
1041
1042 #ifdef CONFIG_PROC_FS
1043         if (!proc_create("nfnetlink_log", 0440,
1044                          net->nf.proc_netfilter, &nful_file_ops))
1045                 return -ENOMEM;
1046 #endif
1047         return 0;
1048 }
1049
1050 static void __net_exit nfnl_log_net_exit(struct net *net)
1051 {
1052 #ifdef CONFIG_PROC_FS
1053         remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1054 #endif
1055         nf_log_unset(net, &nfulnl_logger);
1056 }
1057
1058 static struct pernet_operations nfnl_log_net_ops = {
1059         .init   = nfnl_log_net_init,
1060         .exit   = nfnl_log_net_exit,
1061         .id     = &nfnl_log_net_id,
1062         .size   = sizeof(struct nfnl_log_net),
1063 };
1064
1065 static int __init nfnetlink_log_init(void)
1066 {
1067         int status = -ENOMEM;
1068
1069         netlink_register_notifier(&nfulnl_rtnl_notifier);
1070         status = nfnetlink_subsys_register(&nfulnl_subsys);
1071         if (status < 0) {
1072                 pr_err("log: failed to create netlink socket\n");
1073                 goto cleanup_netlink_notifier;
1074         }
1075
1076         status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1077         if (status < 0) {
1078                 pr_err("log: failed to register logger\n");
1079                 goto cleanup_subsys;
1080         }
1081
1082         status = register_pernet_subsys(&nfnl_log_net_ops);
1083         if (status < 0) {
1084                 pr_err("log: failed to register pernet ops\n");
1085                 goto cleanup_logger;
1086         }
1087         return status;
1088
1089 cleanup_logger:
1090         nf_log_unregister(&nfulnl_logger);
1091 cleanup_subsys:
1092         nfnetlink_subsys_unregister(&nfulnl_subsys);
1093 cleanup_netlink_notifier:
1094         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1095         return status;
1096 }
1097
1098 static void __exit nfnetlink_log_fini(void)
1099 {
1100         unregister_pernet_subsys(&nfnl_log_net_ops);
1101         nf_log_unregister(&nfulnl_logger);
1102         nfnetlink_subsys_unregister(&nfulnl_subsys);
1103         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1104 }
1105
1106 MODULE_DESCRIPTION("netfilter userspace logging");
1107 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1108 MODULE_LICENSE("GPL");
1109 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1110 MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1111 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1112 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1113
1114 module_init(nfnetlink_log_init);
1115 module_exit(nfnetlink_log_fini);