linux/net/netfilter/nfnetlink_log.c
<<
>>
Prefs
   1/*
   2 * This is a module which is used for logging packets to userspace via
   3 * nfetlink.
   4 *
   5 * (C) 2005 by Harald Welte <laforge@netfilter.org>
   6 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
   7 *
   8 * Based on the old ipv4-only ipt_ULOG.c:
   9 * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License version 2 as
  13 * published by the Free Software Foundation.
  14 */
  15
  16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18#include <linux/module.h>
  19#include <linux/skbuff.h>
  20#include <linux/if_arp.h>
  21#include <linux/init.h>
  22#include <linux/ip.h>
  23#include <linux/ipv6.h>
  24#include <linux/netdevice.h>
  25#include <linux/netfilter.h>
  26#include <linux/netfilter_bridge.h>
  27#include <net/netlink.h>
  28#include <linux/netfilter/nfnetlink.h>
  29#include <linux/netfilter/nfnetlink_log.h>
  30#include <linux/netfilter/nf_conntrack_common.h>
  31#include <linux/spinlock.h>
  32#include <linux/sysctl.h>
  33#include <linux/proc_fs.h>
  34#include <linux/security.h>
  35#include <linux/list.h>
  36#include <linux/slab.h>
  37#include <net/sock.h>
  38#include <net/netfilter/nf_log.h>
  39#include <net/netns/generic.h>
  40#include <net/netfilter/nfnetlink_log.h>
  41
  42#include <linux/atomic.h>
  43#include <linux/refcount.h>
  44
  45
  46#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
  47#include "../bridge/br_private.h"
  48#endif
  49
  50#define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  51#define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  52#define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  53/* max packet size is limited by 16-bit struct nfattr nfa_len field */
  54#define NFULNL_COPY_RANGE_MAX   (0xFFFF - NLA_HDRLEN)
  55
  56#define PRINTR(x, args...)      do { if (net_ratelimit()) \
  57                                     printk(x, ## args); } while (0);
  58
  59struct nfulnl_instance {
  60        struct hlist_node hlist;        /* global list of instances */
  61        spinlock_t lock;
  62        refcount_t use;                 /* use count */
  63
  64        unsigned int qlen;              /* number of nlmsgs in skb */
  65        struct sk_buff *skb;            /* pre-allocatd skb */
  66        struct timer_list timer;
  67        struct net *net;
  68        struct user_namespace *peer_user_ns;    /* User namespace of the peer process */
  69        u32 peer_portid;                /* PORTID of the peer process */
  70
  71        /* configurable parameters */
  72        unsigned int flushtimeout;      /* timeout until queue flush */
  73        unsigned int nlbufsiz;          /* netlink buffer allocation size */
  74        unsigned int qthreshold;        /* threshold of the queue */
  75        u_int32_t copy_range;
  76        u_int32_t seq;                  /* instance-local sequential counter */
  77        u_int16_t group_num;            /* number of this queue */
  78        u_int16_t flags;
  79        u_int8_t copy_mode;
  80        struct rcu_head rcu;
  81};
  82
  83#define INSTANCE_BUCKETS        16
  84
  85static unsigned int nfnl_log_net_id __read_mostly;
  86
  87struct nfnl_log_net {
  88        spinlock_t instances_lock;
  89        struct hlist_head instance_table[INSTANCE_BUCKETS];
  90        atomic_t global_seq;
  91};
  92
  93static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
  94{
  95        return net_generic(net, nfnl_log_net_id);
  96}
  97
  98static inline u_int8_t instance_hashfn(u_int16_t group_num)
  99{
 100        return ((group_num & 0xff) % INSTANCE_BUCKETS);
 101}
 102
 103static struct nfulnl_instance *
 104__instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
 105{
 106        struct hlist_head *head;
 107        struct nfulnl_instance *inst;
 108
 109        head = &log->instance_table[instance_hashfn(group_num)];
 110        hlist_for_each_entry_rcu(inst, head, hlist) {
 111                if (inst->group_num == group_num)
 112                        return inst;
 113        }
 114        return NULL;
 115}
 116
 117static inline void
 118instance_get(struct nfulnl_instance *inst)
 119{
 120        refcount_inc(&inst->use);
 121}
 122
 123static struct nfulnl_instance *
 124instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
 125{
 126        struct nfulnl_instance *inst;
 127
 128        rcu_read_lock_bh();
 129        inst = __instance_lookup(log, group_num);
 130        if (inst && !refcount_inc_not_zero(&inst->use))
 131                inst = NULL;
 132        rcu_read_unlock_bh();
 133
 134        return inst;
 135}
 136
 137static void nfulnl_instance_free_rcu(struct rcu_head *head)
 138{
 139        struct nfulnl_instance *inst =
 140                container_of(head, struct nfulnl_instance, rcu);
 141
 142        put_net(inst->net);
 143        kfree(inst);
 144        module_put(THIS_MODULE);
 145}
 146
 147static void
 148instance_put(struct nfulnl_instance *inst)
 149{
 150        if (inst && refcount_dec_and_test(&inst->use))
 151                call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
 152}
 153
 154static void nfulnl_timer(unsigned long data);
 155
 156static struct nfulnl_instance *
 157instance_create(struct net *net, u_int16_t group_num,
 158                u32 portid, struct user_namespace *user_ns)
 159{
 160        struct nfulnl_instance *inst;
 161        struct nfnl_log_net *log = nfnl_log_pernet(net);
 162        int err;
 163
 164        spin_lock_bh(&log->instances_lock);
 165        if (__instance_lookup(log, group_num)) {
 166                err = -EEXIST;
 167                goto out_unlock;
 168        }
 169
 170        inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 171        if (!inst) {
 172                err = -ENOMEM;
 173                goto out_unlock;
 174        }
 175
 176        if (!try_module_get(THIS_MODULE)) {
 177                kfree(inst);
 178                err = -EAGAIN;
 179                goto out_unlock;
 180        }
 181
 182        INIT_HLIST_NODE(&inst->hlist);
 183        spin_lock_init(&inst->lock);
 184        /* needs to be two, since we _put() after creation */
 185        refcount_set(&inst->use, 2);
 186
 187        setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
 188
 189        inst->net = get_net(net);
 190        inst->peer_user_ns = user_ns;
 191        inst->peer_portid = portid;
 192        inst->group_num = group_num;
 193
 194        inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 195        inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 196        inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 197        inst->copy_mode         = NFULNL_COPY_PACKET;
 198        inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 199
 200        hlist_add_head_rcu(&inst->hlist,
 201                       &log->instance_table[instance_hashfn(group_num)]);
 202
 203
 204        spin_unlock_bh(&log->instances_lock);
 205
 206        return inst;
 207
 208out_unlock:
 209        spin_unlock_bh(&log->instances_lock);
 210        return ERR_PTR(err);
 211}
 212
 213static void __nfulnl_flush(struct nfulnl_instance *inst);
 214
 215/* called with BH disabled */
 216static void
 217__instance_destroy(struct nfulnl_instance *inst)
 218{
 219        /* first pull it out of the global list */
 220        hlist_del_rcu(&inst->hlist);
 221
 222        /* then flush all pending packets from skb */
 223
 224        spin_lock(&inst->lock);
 225
 226        /* lockless readers wont be able to use us */
 227        inst->copy_mode = NFULNL_COPY_DISABLED;
 228
 229        if (inst->skb)
 230                __nfulnl_flush(inst);
 231        spin_unlock(&inst->lock);
 232
 233        /* and finally put the refcount */
 234        instance_put(inst);
 235}
 236
 237static inline void
 238instance_destroy(struct nfnl_log_net *log,
 239                 struct nfulnl_instance *inst)
 240{
 241        spin_lock_bh(&log->instances_lock);
 242        __instance_destroy(inst);
 243        spin_unlock_bh(&log->instances_lock);
 244}
 245
 246static int
 247nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 248                  unsigned int range)
 249{
 250        int status = 0;
 251
 252        spin_lock_bh(&inst->lock);
 253
 254        switch (mode) {
 255        case NFULNL_COPY_NONE:
 256        case NFULNL_COPY_META:
 257                inst->copy_mode = mode;
 258                inst->copy_range = 0;
 259                break;
 260
 261        case NFULNL_COPY_PACKET:
 262                inst->copy_mode = mode;
 263                if (range == 0)
 264                        range = NFULNL_COPY_RANGE_MAX;
 265                inst->copy_range = min_t(unsigned int,
 266                                         range, NFULNL_COPY_RANGE_MAX);
 267                break;
 268
 269        default:
 270                status = -EINVAL;
 271                break;
 272        }
 273
 274        spin_unlock_bh(&inst->lock);
 275
 276        return status;
 277}
 278
 279static int
 280nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 281{
 282        int status;
 283
 284        spin_lock_bh(&inst->lock);
 285        if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 286                status = -ERANGE;
 287        else if (nlbufsiz > 131072)
 288                status = -ERANGE;
 289        else {
 290                inst->nlbufsiz = nlbufsiz;
 291                status = 0;
 292        }
 293        spin_unlock_bh(&inst->lock);
 294
 295        return status;
 296}
 297
 298static void
 299nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 300{
 301        spin_lock_bh(&inst->lock);
 302        inst->flushtimeout = timeout;
 303        spin_unlock_bh(&inst->lock);
 304}
 305
 306static void
 307nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 308{
 309        spin_lock_bh(&inst->lock);
 310        inst->qthreshold = qthresh;
 311        spin_unlock_bh(&inst->lock);
 312}
 313
 314static int
 315nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 316{
 317        spin_lock_bh(&inst->lock);
 318        inst->flags = flags;
 319        spin_unlock_bh(&inst->lock);
 320
 321        return 0;
 322}
 323
 324static struct sk_buff *
 325nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
 326                 unsigned int pkt_size)
 327{
 328        struct sk_buff *skb;
 329        unsigned int n;
 330
 331        /* alloc skb which should be big enough for a whole multipart
 332         * message.  WARNING: has to be <= 128k due to slab restrictions */
 333
 334        n = max(inst_size, pkt_size);
 335        skb = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN);
 336        if (!skb) {
 337                if (n > pkt_size) {
 338                        /* try to allocate only as much as we need for current
 339                         * packet */
 340
 341                        skb = alloc_skb(pkt_size, GFP_ATOMIC);
 342                }
 343        }
 344
 345        return skb;
 346}
 347
 348static void
 349__nfulnl_send(struct nfulnl_instance *inst)
 350{
 351        if (inst->qlen > 1) {
 352                struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 353                                                 NLMSG_DONE,
 354                                                 sizeof(struct nfgenmsg),
 355                                                 0);
 356                if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
 357                              inst->skb->len, skb_tailroom(inst->skb))) {
 358                        kfree_skb(inst->skb);
 359                        goto out;
 360                }
 361        }
 362        nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
 363                          MSG_DONTWAIT);
 364out:
 365        inst->qlen = 0;
 366        inst->skb = NULL;
 367}
 368
 369static void
 370__nfulnl_flush(struct nfulnl_instance *inst)
 371{
 372        /* timer holds a reference */
 373        if (del_timer(&inst->timer))
 374                instance_put(inst);
 375        if (inst->skb)
 376                __nfulnl_send(inst);
 377}
 378
 379static void
 380nfulnl_timer(unsigned long data)
 381{
 382        struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 383
 384        spin_lock_bh(&inst->lock);
 385        if (inst->skb)
 386                __nfulnl_send(inst);
 387        spin_unlock_bh(&inst->lock);
 388        instance_put(inst);
 389}
 390
 391/* This is an inline function, we don't really care about a long
 392 * list of arguments */
 393static inline int
 394__build_packet_message(struct nfnl_log_net *log,
 395                        struct nfulnl_instance *inst,
 396                        const struct sk_buff *skb,
 397                        unsigned int data_len,
 398                        u_int8_t pf,
 399                        unsigned int hooknum,
 400                        const struct net_device *indev,
 401                        const struct net_device *outdev,
 402                        const char *prefix, unsigned int plen,
 403                        const struct nfnl_ct_hook *nfnl_ct,
 404                        struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 405{
 406        struct nfulnl_msg_packet_hdr pmsg;
 407        struct nlmsghdr *nlh;
 408        struct nfgenmsg *nfmsg;
 409        sk_buff_data_t old_tail = inst->skb->tail;
 410        struct sock *sk;
 411        const unsigned char *hwhdrp;
 412
 413        nlh = nlmsg_put(inst->skb, 0, 0,
 414                        nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET),
 415                        sizeof(struct nfgenmsg), 0);
 416        if (!nlh)
 417                return -1;
 418        nfmsg = nlmsg_data(nlh);
 419        nfmsg->nfgen_family = pf;
 420        nfmsg->version = NFNETLINK_V0;
 421        nfmsg->res_id = htons(inst->group_num);
 422
 423        memset(&pmsg, 0, sizeof(pmsg));
 424        pmsg.hw_protocol        = skb->protocol;
 425        pmsg.hook               = hooknum;
 426
 427        if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
 428                goto nla_put_failure;
 429
 430        if (prefix &&
 431            nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
 432                goto nla_put_failure;
 433
 434        if (indev) {
 435#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 436                if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 437                                 htonl(indev->ifindex)))
 438                        goto nla_put_failure;
 439#else
 440                if (pf == PF_BRIDGE) {
 441                        /* Case 1: outdev is physical input device, we need to
 442                         * look for bridge group (when called from
 443                         * netfilter_bridge) */
 444                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 445                                         htonl(indev->ifindex)) ||
 446                        /* this is the bridge group "brX" */
 447                        /* rcu_read_lock()ed by nf_hook_thresh or
 448                         * nf_log_packet.
 449                         */
 450                            nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 451                                         htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 452                                goto nla_put_failure;
 453                } else {
 454                        struct net_device *physindev;
 455
 456                        /* Case 2: indev is bridge group, we need to look for
 457                         * physical device (when called from ipv4) */
 458                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 459                                         htonl(indev->ifindex)))
 460                                goto nla_put_failure;
 461
 462                        physindev = nf_bridge_get_physindev(skb);
 463                        if (physindev &&
 464                            nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 465                                         htonl(physindev->ifindex)))
 466                                goto nla_put_failure;
 467                }
 468#endif
 469        }
 470
 471        if (outdev) {
 472#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 473                if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 474                                 htonl(outdev->ifindex)))
 475                        goto nla_put_failure;
 476#else
 477                if (pf == PF_BRIDGE) {
 478                        /* Case 1: outdev is physical output device, we need to
 479                         * look for bridge group (when called from
 480                         * netfilter_bridge) */
 481                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 482                                         htonl(outdev->ifindex)) ||
 483                        /* this is the bridge group "brX" */
 484                        /* rcu_read_lock()ed by nf_hook_thresh or
 485                         * nf_log_packet.
 486                         */
 487                            nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 488                                         htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 489                                goto nla_put_failure;
 490                } else {
 491                        struct net_device *physoutdev;
 492
 493                        /* Case 2: indev is a bridge group, we need to look
 494                         * for physical device (when called from ipv4) */
 495                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 496                                         htonl(outdev->ifindex)))
 497                                goto nla_put_failure;
 498
 499                        physoutdev = nf_bridge_get_physoutdev(skb);
 500                        if (physoutdev &&
 501                            nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 502                                         htonl(physoutdev->ifindex)))
 503                                goto nla_put_failure;
 504                }
 505#endif
 506        }
 507
 508        if (skb->mark &&
 509            nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
 510                goto nla_put_failure;
 511
 512        if (indev && skb->dev &&
 513            skb->mac_header != skb->network_header) {
 514                struct nfulnl_msg_packet_hw phw;
 515                int len;
 516
 517                memset(&phw, 0, sizeof(phw));
 518                len = dev_parse_header(skb, phw.hw_addr);
 519                if (len > 0) {
 520                        phw.hw_addrlen = htons(len);
 521                        if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 522                                goto nla_put_failure;
 523                }
 524        }
 525
 526        if (indev && skb_mac_header_was_set(skb)) {
 527                if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 528                    nla_put_be16(inst->skb, NFULA_HWLEN,
 529                                 htons(skb->dev->hard_header_len)))
 530                        goto nla_put_failure;
 531
 532                hwhdrp = skb_mac_header(skb);
 533
 534                if (skb->dev->type == ARPHRD_SIT)
 535                        hwhdrp -= ETH_HLEN;
 536
 537                if (hwhdrp >= skb->head &&
 538                    nla_put(inst->skb, NFULA_HWHEADER,
 539                            skb->dev->hard_header_len, hwhdrp))
 540                        goto nla_put_failure;
 541        }
 542
 543        if (skb->tstamp) {
 544                struct nfulnl_msg_packet_timestamp ts;
 545                struct timespec64 kts = ktime_to_timespec64(skb->tstamp);
 546                ts.sec = cpu_to_be64(kts.tv_sec);
 547                ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);
 548
 549                if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 550                        goto nla_put_failure;
 551        }
 552
 553        /* UID */
 554        sk = skb->sk;
 555        if (sk && sk_fullsock(sk)) {
 556                read_lock_bh(&sk->sk_callback_lock);
 557                if (sk->sk_socket && sk->sk_socket->file) {
 558                        struct file *file = sk->sk_socket->file;
 559                        const struct cred *cred = file->f_cred;
 560                        struct user_namespace *user_ns = inst->peer_user_ns;
 561                        __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
 562                        __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
 563                        read_unlock_bh(&sk->sk_callback_lock);
 564                        if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 565                            nla_put_be32(inst->skb, NFULA_GID, gid))
 566                                goto nla_put_failure;
 567                } else
 568                        read_unlock_bh(&sk->sk_callback_lock);
 569        }
 570
 571        /* local sequence number */
 572        if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 573            nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 574                goto nla_put_failure;
 575
 576        /* global sequence number */
 577        if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 578            nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 579                         htonl(atomic_inc_return(&log->global_seq))))
 580                goto nla_put_failure;
 581
 582        if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
 583                                 NFULA_CT, NFULA_CT_INFO) < 0)
 584                goto nla_put_failure;
 585
 586        if (data_len) {
 587                struct nlattr *nla;
 588                int size = nla_attr_size(data_len);
 589
 590                if (skb_tailroom(inst->skb) < nla_total_size(data_len))
 591                        goto nla_put_failure;
 592
 593                nla = skb_put(inst->skb, nla_total_size(data_len));
 594                nla->nla_type = NFULA_PAYLOAD;
 595                nla->nla_len = size;
 596
 597                if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 598                        BUG();
 599        }
 600
 601        nlh->nlmsg_len = inst->skb->tail - old_tail;
 602        return 0;
 603
 604nla_put_failure:
 605        PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 606        return -1;
 607}
 608
 609static const struct nf_loginfo default_loginfo = {
 610        .type =         NF_LOG_TYPE_ULOG,
 611        .u = {
 612                .ulog = {
 613                        .copy_len       = 0xffff,
 614                        .group          = 0,
 615                        .qthreshold     = 1,
 616                },
 617        },
 618};
 619
 620/* log handler for internal netfilter logging api */
 621void
 622nfulnl_log_packet(struct net *net,
 623                  u_int8_t pf,
 624                  unsigned int hooknum,
 625                  const struct sk_buff *skb,
 626                  const struct net_device *in,
 627                  const struct net_device *out,
 628                  const struct nf_loginfo *li_user,
 629                  const char *prefix)
 630{
 631        size_t size;
 632        unsigned int data_len;
 633        struct nfulnl_instance *inst;
 634        const struct nf_loginfo *li;
 635        unsigned int qthreshold;
 636        unsigned int plen;
 637        struct nfnl_log_net *log = nfnl_log_pernet(net);
 638        const struct nfnl_ct_hook *nfnl_ct = NULL;
 639        struct nf_conn *ct = NULL;
 640        enum ip_conntrack_info uninitialized_var(ctinfo);
 641
 642        if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 643                li = li_user;
 644        else
 645                li = &default_loginfo;
 646
 647        inst = instance_lookup_get(log, li->u.ulog.group);
 648        if (!inst)
 649                return;
 650
 651        plen = 0;
 652        if (prefix)
 653                plen = strlen(prefix) + 1;
 654
 655        /* FIXME: do we want to make the size calculation conditional based on
 656         * what is actually present?  way more branches and checks, but more
 657         * memory efficient... */
 658        size =    nlmsg_total_size(sizeof(struct nfgenmsg))
 659                + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 660                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 661                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 662#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 663                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 664                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 665#endif
 666                + nla_total_size(sizeof(u_int32_t))     /* mark */
 667                + nla_total_size(sizeof(u_int32_t))     /* uid */
 668                + nla_total_size(sizeof(u_int32_t))     /* gid */
 669                + nla_total_size(plen)                  /* prefix */
 670                + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 671                + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
 672                + nla_total_size(sizeof(struct nfgenmsg));      /* NLMSG_DONE */
 673
 674        if (in && skb_mac_header_was_set(skb)) {
 675                size +=   nla_total_size(skb->dev->hard_header_len)
 676                        + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 677                        + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 678        }
 679
 680        spin_lock_bh(&inst->lock);
 681
 682        if (inst->flags & NFULNL_CFG_F_SEQ)
 683                size += nla_total_size(sizeof(u_int32_t));
 684        if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 685                size += nla_total_size(sizeof(u_int32_t));
 686        if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
 687                nfnl_ct = rcu_dereference(nfnl_ct_hook);
 688                if (nfnl_ct != NULL) {
 689                        ct = nfnl_ct->get_ct(skb, &ctinfo);
 690                        if (ct != NULL)
 691                                size += nfnl_ct->build_size(ct);
 692                }
 693        }
 694
 695        qthreshold = inst->qthreshold;
 696        /* per-rule qthreshold overrides per-instance */
 697        if (li->u.ulog.qthreshold)
 698                if (qthreshold > li->u.ulog.qthreshold)
 699                        qthreshold = li->u.ulog.qthreshold;
 700
 701
 702        switch (inst->copy_mode) {
 703        case NFULNL_COPY_META:
 704        case NFULNL_COPY_NONE:
 705                data_len = 0;
 706                break;
 707
 708        case NFULNL_COPY_PACKET:
 709                data_len = inst->copy_range;
 710                if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) &&
 711                    (li->u.ulog.copy_len < data_len))
 712                        data_len = li->u.ulog.copy_len;
 713
 714                if (data_len > skb->len)
 715                        data_len = skb->len;
 716
 717                size += nla_total_size(data_len);
 718                break;
 719
 720        case NFULNL_COPY_DISABLED:
 721        default:
 722                goto unlock_and_release;
 723        }
 724
 725        if (inst->skb && size > skb_tailroom(inst->skb)) {
 726                /* either the queue len is too high or we don't have
 727                 * enough room in the skb left. flush to userspace. */
 728                __nfulnl_flush(inst);
 729        }
 730
 731        if (!inst->skb) {
 732                inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
 733                                             inst->nlbufsiz, size);
 734                if (!inst->skb)
 735                        goto alloc_failure;
 736        }
 737
 738        inst->qlen++;
 739
 740        __build_packet_message(log, inst, skb, data_len, pf,
 741                                hooknum, in, out, prefix, plen,
 742                                nfnl_ct, ct, ctinfo);
 743
 744        if (inst->qlen >= qthreshold)
 745                __nfulnl_flush(inst);
 746        /* timer_pending always called within inst->lock, so there
 747         * is no chance of a race here */
 748        else if (!timer_pending(&inst->timer)) {
 749                instance_get(inst);
 750                inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 751                add_timer(&inst->timer);
 752        }
 753
 754unlock_and_release:
 755        spin_unlock_bh(&inst->lock);
 756        instance_put(inst);
 757        return;
 758
 759alloc_failure:
 760        /* FIXME: statistics */
 761        goto unlock_and_release;
 762}
 763EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 764
 765static int
 766nfulnl_rcv_nl_event(struct notifier_block *this,
 767                   unsigned long event, void *ptr)
 768{
 769        struct netlink_notify *n = ptr;
 770        struct nfnl_log_net *log = nfnl_log_pernet(n->net);
 771
 772        if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 773                int i;
 774
 775                /* destroy all instances for this portid */
 776                spin_lock_bh(&log->instances_lock);
 777                for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 778                        struct hlist_node *t2;
 779                        struct nfulnl_instance *inst;
 780                        struct hlist_head *head = &log->instance_table[i];
 781
 782                        hlist_for_each_entry_safe(inst, t2, head, hlist) {
 783                                if (n->portid == inst->peer_portid)
 784                                        __instance_destroy(inst);
 785                        }
 786                }
 787                spin_unlock_bh(&log->instances_lock);
 788        }
 789        return NOTIFY_DONE;
 790}
 791
 792static struct notifier_block nfulnl_rtnl_notifier = {
 793        .notifier_call  = nfulnl_rcv_nl_event,
 794};
 795
 796static int nfulnl_recv_unsupp(struct net *net, struct sock *ctnl,
 797                              struct sk_buff *skb, const struct nlmsghdr *nlh,
 798                              const struct nlattr * const nfqa[],
 799                              struct netlink_ext_ack *extack)
 800{
 801        return -ENOTSUPP;
 802}
 803
 804static struct nf_logger nfulnl_logger __read_mostly = {
 805        .name   = "nfnetlink_log",
 806        .type   = NF_LOG_TYPE_ULOG,
 807        .logfn  = nfulnl_log_packet,
 808        .me     = THIS_MODULE,
 809};
 810
 811static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 812        [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 813        [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 814        [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 815        [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 816        [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 817        [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 818};
 819
 820static int nfulnl_recv_config(struct net *net, struct sock *ctnl,
 821                              struct sk_buff *skb, const struct nlmsghdr *nlh,
 822                              const struct nlattr * const nfula[],
 823                              struct netlink_ext_ack *extack)
 824{
 825        struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 826        u_int16_t group_num = ntohs(nfmsg->res_id);
 827        struct nfulnl_instance *inst;
 828        struct nfulnl_msg_config_cmd *cmd = NULL;
 829        struct nfnl_log_net *log = nfnl_log_pernet(net);
 830        int ret = 0;
 831        u16 flags = 0;
 832
 833        if (nfula[NFULA_CFG_CMD]) {
 834                u_int8_t pf = nfmsg->nfgen_family;
 835                cmd = nla_data(nfula[NFULA_CFG_CMD]);
 836
 837                /* Commands without queue context */
 838                switch (cmd->command) {
 839                case NFULNL_CFG_CMD_PF_BIND:
 840                        return nf_log_bind_pf(net, pf, &nfulnl_logger);
 841                case NFULNL_CFG_CMD_PF_UNBIND:
 842                        nf_log_unbind_pf(net, pf);
 843                        return 0;
 844                }
 845        }
 846
 847        inst = instance_lookup_get(log, group_num);
 848        if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
 849                ret = -EPERM;
 850                goto out_put;
 851        }
 852
 853        /* Check if we support these flags in first place, dependencies should
 854         * be there too not to break atomicity.
 855         */
 856        if (nfula[NFULA_CFG_FLAGS]) {
 857                flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
 858
 859                if ((flags & NFULNL_CFG_F_CONNTRACK) &&
 860                    !rcu_access_pointer(nfnl_ct_hook)) {
 861#ifdef CONFIG_MODULES
 862                        nfnl_unlock(NFNL_SUBSYS_ULOG);
 863                        request_module("ip_conntrack_netlink");
 864                        nfnl_lock(NFNL_SUBSYS_ULOG);
 865                        if (rcu_access_pointer(nfnl_ct_hook)) {
 866                                ret = -EAGAIN;
 867                                goto out_put;
 868                        }
 869#endif
 870                        ret = -EOPNOTSUPP;
 871                        goto out_put;
 872                }
 873        }
 874
 875        if (cmd != NULL) {
 876                switch (cmd->command) {
 877                case NFULNL_CFG_CMD_BIND:
 878                        if (inst) {
 879                                ret = -EBUSY;
 880                                goto out_put;
 881                        }
 882
 883                        inst = instance_create(net, group_num,
 884                                               NETLINK_CB(skb).portid,
 885                                               sk_user_ns(NETLINK_CB(skb).sk));
 886                        if (IS_ERR(inst)) {
 887                                ret = PTR_ERR(inst);
 888                                goto out;
 889                        }
 890                        break;
 891                case NFULNL_CFG_CMD_UNBIND:
 892                        if (!inst) {
 893                                ret = -ENODEV;
 894                                goto out;
 895                        }
 896
 897                        instance_destroy(log, inst);
 898                        goto out_put;
 899                default:
 900                        ret = -ENOTSUPP;
 901                        goto out_put;
 902                }
 903        } else if (!inst) {
 904                ret = -ENODEV;
 905                goto out;
 906        }
 907
 908        if (nfula[NFULA_CFG_MODE]) {
 909                struct nfulnl_msg_config_mode *params =
 910                        nla_data(nfula[NFULA_CFG_MODE]);
 911
 912                nfulnl_set_mode(inst, params->copy_mode,
 913                                ntohl(params->copy_range));
 914        }
 915
 916        if (nfula[NFULA_CFG_TIMEOUT]) {
 917                __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 918
 919                nfulnl_set_timeout(inst, ntohl(timeout));
 920        }
 921
 922        if (nfula[NFULA_CFG_NLBUFSIZ]) {
 923                __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 924
 925                nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 926        }
 927
 928        if (nfula[NFULA_CFG_QTHRESH]) {
 929                __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 930
 931                nfulnl_set_qthresh(inst, ntohl(qthresh));
 932        }
 933
 934        if (nfula[NFULA_CFG_FLAGS])
 935                nfulnl_set_flags(inst, flags);
 936
 937out_put:
 938        instance_put(inst);
 939out:
 940        return ret;
 941}
 942
 943static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 944        [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 945                                    .attr_count = NFULA_MAX, },
 946        [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 947                                    .attr_count = NFULA_CFG_MAX,
 948                                    .policy = nfula_cfg_policy },
 949};
 950
 951static const struct nfnetlink_subsystem nfulnl_subsys = {
 952        .name           = "log",
 953        .subsys_id      = NFNL_SUBSYS_ULOG,
 954        .cb_count       = NFULNL_MSG_MAX,
 955        .cb             = nfulnl_cb,
 956};
 957
 958#ifdef CONFIG_PROC_FS
 959struct iter_state {
 960        struct seq_net_private p;
 961        unsigned int bucket;
 962};
 963
 964static struct hlist_node *get_first(struct net *net, struct iter_state *st)
 965{
 966        struct nfnl_log_net *log;
 967        if (!st)
 968                return NULL;
 969
 970        log = nfnl_log_pernet(net);
 971
 972        for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 973                struct hlist_head *head = &log->instance_table[st->bucket];
 974
 975                if (!hlist_empty(head))
 976                        return rcu_dereference_bh(hlist_first_rcu(head));
 977        }
 978        return NULL;
 979}
 980
 981static struct hlist_node *get_next(struct net *net, struct iter_state *st,
 982                                   struct hlist_node *h)
 983{
 984        h = rcu_dereference_bh(hlist_next_rcu(h));
 985        while (!h) {
 986                struct nfnl_log_net *log;
 987                struct hlist_head *head;
 988
 989                if (++st->bucket >= INSTANCE_BUCKETS)
 990                        return NULL;
 991
 992                log = nfnl_log_pernet(net);
 993                head = &log->instance_table[st->bucket];
 994                h = rcu_dereference_bh(hlist_first_rcu(head));
 995        }
 996        return h;
 997}
 998
 999static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
1000                                  loff_t pos)
1001{
1002        struct hlist_node *head;
1003        head = get_first(net, st);
1004
1005        if (head)
1006                while (pos && (head = get_next(net, st, head)))
1007                        pos--;
1008        return pos ? NULL : head;
1009}
1010
1011static void *seq_start(struct seq_file *s, loff_t *pos)
1012        __acquires(rcu_bh)
1013{
1014        rcu_read_lock_bh();
1015        return get_idx(seq_file_net(s), s->private, *pos);
1016}
1017
1018static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
1019{
1020        (*pos)++;
1021        return get_next(seq_file_net(s), s->private, v);
1022}
1023
1024static void seq_stop(struct seq_file *s, void *v)
1025        __releases(rcu_bh)
1026{
1027        rcu_read_unlock_bh();
1028}
1029
1030static int seq_show(struct seq_file *s, void *v)
1031{
1032        const struct nfulnl_instance *inst = v;
1033
1034        seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1035                   inst->group_num,
1036                   inst->peer_portid, inst->qlen,
1037                   inst->copy_mode, inst->copy_range,
1038                   inst->flushtimeout, refcount_read(&inst->use));
1039
1040        return 0;
1041}
1042
1043static const struct seq_operations nful_seq_ops = {
1044        .start  = seq_start,
1045        .next   = seq_next,
1046        .stop   = seq_stop,
1047        .show   = seq_show,
1048};
1049
1050static int nful_open(struct inode *inode, struct file *file)
1051{
1052        return seq_open_net(inode, file, &nful_seq_ops,
1053                            sizeof(struct iter_state));
1054}
1055
1056static const struct file_operations nful_file_ops = {
1057        .owner   = THIS_MODULE,
1058        .open    = nful_open,
1059        .read    = seq_read,
1060        .llseek  = seq_lseek,
1061        .release = seq_release_net,
1062};
1063
1064#endif /* PROC_FS */
1065
1066static int __net_init nfnl_log_net_init(struct net *net)
1067{
1068        unsigned int i;
1069        struct nfnl_log_net *log = nfnl_log_pernet(net);
1070#ifdef CONFIG_PROC_FS
1071        struct proc_dir_entry *proc;
1072        kuid_t root_uid;
1073        kgid_t root_gid;
1074#endif
1075
1076        for (i = 0; i < INSTANCE_BUCKETS; i++)
1077                INIT_HLIST_HEAD(&log->instance_table[i]);
1078        spin_lock_init(&log->instances_lock);
1079
1080#ifdef CONFIG_PROC_FS
1081        proc = proc_create("nfnetlink_log", 0440,
1082                           net->nf.proc_netfilter, &nful_file_ops);
1083        if (!proc)
1084                return -ENOMEM;
1085
1086        root_uid = make_kuid(net->user_ns, 0);
1087        root_gid = make_kgid(net->user_ns, 0);
1088        if (uid_valid(root_uid) && gid_valid(root_gid))
1089                proc_set_user(proc, root_uid, root_gid);
1090#endif
1091        return 0;
1092}
1093
1094static void __net_exit nfnl_log_net_exit(struct net *net)
1095{
1096#ifdef CONFIG_PROC_FS
1097        remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1098#endif
1099        nf_log_unset(net, &nfulnl_logger);
1100}
1101
1102static struct pernet_operations nfnl_log_net_ops = {
1103        .init   = nfnl_log_net_init,
1104        .exit   = nfnl_log_net_exit,
1105        .id     = &nfnl_log_net_id,
1106        .size   = sizeof(struct nfnl_log_net),
1107};
1108
1109static int __init nfnetlink_log_init(void)
1110{
1111        int status;
1112
1113        status = register_pernet_subsys(&nfnl_log_net_ops);
1114        if (status < 0) {
1115                pr_err("failed to register pernet ops\n");
1116                goto out;
1117        }
1118
1119        netlink_register_notifier(&nfulnl_rtnl_notifier);
1120        status = nfnetlink_subsys_register(&nfulnl_subsys);
1121        if (status < 0) {
1122                pr_err("failed to create netlink socket\n");
1123                goto cleanup_netlink_notifier;
1124        }
1125
1126        status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1127        if (status < 0) {
1128                pr_err("failed to register logger\n");
1129                goto cleanup_subsys;
1130        }
1131
1132        return status;
1133
1134cleanup_subsys:
1135        nfnetlink_subsys_unregister(&nfulnl_subsys);
1136cleanup_netlink_notifier:
1137        netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1138        unregister_pernet_subsys(&nfnl_log_net_ops);
1139out:
1140        return status;
1141}
1142
1143static void __exit nfnetlink_log_fini(void)
1144{
1145        nfnetlink_subsys_unregister(&nfulnl_subsys);
1146        netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1147        unregister_pernet_subsys(&nfnl_log_net_ops);
1148        nf_log_unregister(&nfulnl_logger);
1149}
1150
1151MODULE_DESCRIPTION("netfilter userspace logging");
1152MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1153MODULE_LICENSE("GPL");
1154MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1155MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1156MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1157MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1158MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */
1159MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */
1160
1161module_init(nfnetlink_log_init);
1162module_exit(nfnetlink_log_fini);
1163