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