1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * This is a module which is used for logging packets to userspace via 4 * nfetlink. 5 * 6 * (C) 2005 by Harald Welte <laforge@netfilter.org> 7 * (C) 2006-2012 Patrick McHardy <kaber@trash.net> 8 * 9 * Based on the old ipv4-only ipt_ULOG.c: 10 * (C) 2000-2004 by Harald Welte <laforge@netfilter.org> 11 */ 12 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 15 #include <linux/module.h> 16 #include <linux/skbuff.h> 17 #include <linux/if_arp.h> 18 #include <linux/init.h> 19 #include <linux/ip.h> 20 #include <linux/ipv6.h> 21 #include <linux/netdevice.h> 22 #include <linux/netfilter.h> 23 #include <linux/netfilter_bridge.h> 24 #include <net/netlink.h> 25 #include <linux/netfilter/nfnetlink.h> 26 #include <linux/netfilter/nfnetlink_log.h> 27 #include <linux/netfilter/nf_conntrack_common.h> 28 #include <linux/spinlock.h> 29 #include <linux/sysctl.h> 30 #include <linux/proc_fs.h> 31 #include <linux/security.h> 32 #include <linux/list.h> 33 #include <linux/slab.h> 34 #include <net/sock.h> 35 #include <net/netfilter/nf_log.h> 36 #include <net/netns/generic.h> 37 38 #include <linux/atomic.h> 39 #include <linux/refcount.h> 40 41 42 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 43 #include "../bridge/br_private.h" 44 #endif 45 46 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 47 #include <net/netfilter/nf_conntrack.h> 48 #endif 49 50 #define NFULNL_COPY_DISABLED 0xff 51 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE 52 #define NFULNL_TIMEOUT_DEFAULT 100 /* every second */ 53 #define NFULNL_QTHRESH_DEFAULT 100 /* 100 packets */ 54 /* max packet size is limited by 16-bit struct nfattr nfa_len field */ 55 #define NFULNL_COPY_RANGE_MAX (0xFFFF - NLA_HDRLEN) 56 57 #define PRINTR(x, args...) do { if (net_ratelimit()) \ 58 printk(x, ## args); } while (0); 59 60 struct nfulnl_instance { 61 struct hlist_node hlist; /* global list of instances */ 62 spinlock_t lock; 63 refcount_t use; /* use count */ 64 65 unsigned int qlen; /* number of nlmsgs in skb */ 66 struct sk_buff *skb; /* pre-allocatd skb */ 67 struct timer_list timer; 68 struct net *net; 69 netns_tracker ns_tracker; 70 struct user_namespace *peer_user_ns; /* User namespace of the peer process */ 71 u32 peer_portid; /* PORTID of the peer process */ 72 73 /* configurable parameters */ 74 unsigned int flushtimeout; /* timeout until queue flush */ 75 unsigned int nlbufsiz; /* netlink buffer allocation size */ 76 unsigned int qthreshold; /* threshold of the queue */ 77 u_int32_t copy_range; 78 u_int32_t seq; /* instance-local sequential counter */ 79 u_int16_t group_num; /* number of this queue */ 80 u_int16_t flags; 81 u_int8_t copy_mode; 82 struct rcu_head rcu; 83 }; 84 85 #define INSTANCE_BUCKETS 16 86 87 static unsigned int nfnl_log_net_id __read_mostly; 88 89 struct nfnl_log_net { 90 spinlock_t instances_lock; 91 struct hlist_head instance_table[INSTANCE_BUCKETS]; 92 atomic_t global_seq; 93 }; 94 95 static struct nfnl_log_net *nfnl_log_pernet(struct net *net) 96 { 97 return net_generic(net, nfnl_log_net_id); 98 } 99 100 static inline u_int8_t instance_hashfn(u_int16_t group_num) 101 { 102 return ((group_num & 0xff) % INSTANCE_BUCKETS); 103 } 104 105 static struct nfulnl_instance * 106 __instance_lookup(const struct nfnl_log_net *log, u16 group_num) 107 { 108 const struct hlist_head *head; 109 struct nfulnl_instance *inst; 110 111 head = &log->instance_table[instance_hashfn(group_num)]; 112 hlist_for_each_entry_rcu(inst, head, hlist) { 113 if (inst->group_num == group_num) 114 return inst; 115 } 116 return NULL; 117 } 118 119 static inline void 120 instance_get(struct nfulnl_instance *inst) 121 { 122 refcount_inc(&inst->use); 123 } 124 125 static struct nfulnl_instance * 126 instance_lookup_get_rcu(const struct nfnl_log_net *log, u16 group_num) 127 { 128 struct nfulnl_instance *inst; 129 130 inst = __instance_lookup(log, group_num); 131 if (inst && !refcount_inc_not_zero(&inst->use)) 132 inst = NULL; 133 134 return inst; 135 } 136 137 static struct nfulnl_instance * 138 instance_lookup_get(const struct nfnl_log_net *log, u16 group_num) 139 { 140 struct nfulnl_instance *inst; 141 142 rcu_read_lock(); 143 inst = instance_lookup_get_rcu(log, group_num); 144 rcu_read_unlock(); 145 146 return inst; 147 } 148 149 static void nfulnl_instance_free_rcu(struct rcu_head *head) 150 { 151 struct nfulnl_instance *inst = 152 container_of(head, struct nfulnl_instance, rcu); 153 154 put_net_track(inst->net, &inst->ns_tracker); 155 kfree(inst); 156 module_put(THIS_MODULE); 157 } 158 159 static void 160 instance_put(struct nfulnl_instance *inst) 161 { 162 if (inst && refcount_dec_and_test(&inst->use)) 163 call_rcu(&inst->rcu, nfulnl_instance_free_rcu); 164 } 165 166 static void nfulnl_timer(struct timer_list *t); 167 168 static struct nfulnl_instance * 169 instance_create(struct net *net, u_int16_t group_num, 170 u32 portid, struct user_namespace *user_ns) 171 { 172 struct nfulnl_instance *inst; 173 struct nfnl_log_net *log = nfnl_log_pernet(net); 174 int err; 175 176 spin_lock_bh(&log->instances_lock); 177 if (__instance_lookup(log, group_num)) { 178 err = -EEXIST; 179 goto out_unlock; 180 } 181 182 inst = kzalloc(sizeof(*inst), GFP_ATOMIC); 183 if (!inst) { 184 err = -ENOMEM; 185 goto out_unlock; 186 } 187 188 if (!try_module_get(THIS_MODULE)) { 189 kfree(inst); 190 err = -EAGAIN; 191 goto out_unlock; 192 } 193 194 INIT_HLIST_NODE(&inst->hlist); 195 spin_lock_init(&inst->lock); 196 /* needs to be two, since we _put() after creation */ 197 refcount_set(&inst->use, 2); 198 199 timer_setup(&inst->timer, nfulnl_timer, 0); 200 201 inst->net = get_net_track(net, &inst->ns_tracker, GFP_ATOMIC); 202 inst->peer_user_ns = user_ns; 203 inst->peer_portid = portid; 204 inst->group_num = group_num; 205 206 inst->qthreshold = NFULNL_QTHRESH_DEFAULT; 207 inst->flushtimeout = NFULNL_TIMEOUT_DEFAULT; 208 inst->nlbufsiz = NFULNL_NLBUFSIZ_DEFAULT; 209 inst->copy_mode = NFULNL_COPY_PACKET; 210 inst->copy_range = NFULNL_COPY_RANGE_MAX; 211 212 hlist_add_head_rcu(&inst->hlist, 213 &log->instance_table[instance_hashfn(group_num)]); 214 215 216 spin_unlock_bh(&log->instances_lock); 217 218 return inst; 219 220 out_unlock: 221 spin_unlock_bh(&log->instances_lock); 222 return ERR_PTR(err); 223 } 224 225 static void __nfulnl_flush(struct nfulnl_instance *inst); 226 227 /* called with BH disabled */ 228 static void 229 __instance_destroy(struct nfulnl_instance *inst) 230 { 231 /* first pull it out of the global list */ 232 hlist_del_rcu(&inst->hlist); 233 234 /* then flush all pending packets from skb */ 235 236 spin_lock(&inst->lock); 237 238 /* lockless readers wont be able to use us */ 239 inst->copy_mode = NFULNL_COPY_DISABLED; 240 241 if (inst->skb) 242 __nfulnl_flush(inst); 243 spin_unlock(&inst->lock); 244 245 /* and finally put the refcount */ 246 instance_put(inst); 247 } 248 249 static inline void 250 instance_destroy(struct nfnl_log_net *log, 251 struct nfulnl_instance *inst) 252 { 253 spin_lock_bh(&log->instances_lock); 254 __instance_destroy(inst); 255 spin_unlock_bh(&log->instances_lock); 256 } 257 258 static int 259 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode, 260 unsigned int range) 261 { 262 int status = 0; 263 264 spin_lock_bh(&inst->lock); 265 266 switch (mode) { 267 case NFULNL_COPY_NONE: 268 case NFULNL_COPY_META: 269 inst->copy_mode = mode; 270 inst->copy_range = 0; 271 break; 272 273 case NFULNL_COPY_PACKET: 274 inst->copy_mode = mode; 275 if (range == 0) 276 range = NFULNL_COPY_RANGE_MAX; 277 inst->copy_range = min_t(unsigned int, 278 range, NFULNL_COPY_RANGE_MAX); 279 break; 280 281 default: 282 status = -EINVAL; 283 break; 284 } 285 286 spin_unlock_bh(&inst->lock); 287 288 return status; 289 } 290 291 static int 292 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz) 293 { 294 int status; 295 296 spin_lock_bh(&inst->lock); 297 if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT) 298 status = -ERANGE; 299 else if (nlbufsiz > 131072) 300 status = -ERANGE; 301 else { 302 inst->nlbufsiz = nlbufsiz; 303 status = 0; 304 } 305 spin_unlock_bh(&inst->lock); 306 307 return status; 308 } 309 310 static void 311 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout) 312 { 313 spin_lock_bh(&inst->lock); 314 inst->flushtimeout = timeout; 315 spin_unlock_bh(&inst->lock); 316 } 317 318 static void 319 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh) 320 { 321 spin_lock_bh(&inst->lock); 322 inst->qthreshold = qthresh; 323 spin_unlock_bh(&inst->lock); 324 } 325 326 static int 327 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags) 328 { 329 spin_lock_bh(&inst->lock); 330 inst->flags = flags; 331 spin_unlock_bh(&inst->lock); 332 333 return 0; 334 } 335 336 static struct sk_buff * 337 nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size, 338 unsigned int pkt_size) 339 { 340 struct sk_buff *skb; 341 unsigned int n; 342 343 /* alloc skb which should be big enough for a whole multipart 344 * message. WARNING: has to be <= 128k due to slab restrictions */ 345 346 n = max(inst_size, pkt_size); 347 skb = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN); 348 if (!skb) { 349 if (n > pkt_size) { 350 /* try to allocate only as much as we need for current 351 * packet */ 352 353 skb = alloc_skb(pkt_size, GFP_ATOMIC); 354 } 355 } 356 357 return skb; 358 } 359 360 static void 361 __nfulnl_send(struct nfulnl_instance *inst) 362 { 363 if (inst->qlen > 1) { 364 struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0, 365 NLMSG_DONE, 366 sizeof(struct nfgenmsg), 367 0); 368 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n", 369 inst->skb->len, skb_tailroom(inst->skb))) { 370 kfree_skb(inst->skb); 371 goto out; 372 } 373 } 374 nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid); 375 out: 376 inst->qlen = 0; 377 inst->skb = NULL; 378 } 379 380 static void 381 __nfulnl_flush(struct nfulnl_instance *inst) 382 { 383 /* timer holds a reference */ 384 if (del_timer(&inst->timer)) 385 instance_put(inst); 386 if (inst->skb) 387 __nfulnl_send(inst); 388 } 389 390 static void 391 nfulnl_timer(struct timer_list *t) 392 { 393 struct nfulnl_instance *inst = from_timer(inst, t, timer); 394 395 spin_lock_bh(&inst->lock); 396 if (inst->skb) 397 __nfulnl_send(inst); 398 spin_unlock_bh(&inst->lock); 399 instance_put(inst); 400 } 401 402 static u32 nfulnl_get_bridge_size(const struct sk_buff *skb) 403 { 404 u32 size = 0; 405 406 if (!skb_mac_header_was_set(skb)) 407 return 0; 408 409 if (skb_vlan_tag_present(skb)) { 410 size += nla_total_size(0); /* nested */ 411 size += nla_total_size(sizeof(u16)); /* id */ 412 size += nla_total_size(sizeof(u16)); /* tag */ 413 } 414 415 if (skb->network_header > skb->mac_header) 416 size += nla_total_size(skb->network_header - skb->mac_header); 417 418 return size; 419 } 420 421 static int nfulnl_put_bridge(struct nfulnl_instance *inst, const struct sk_buff *skb) 422 { 423 if (!skb_mac_header_was_set(skb)) 424 return 0; 425 426 if (skb_vlan_tag_present(skb)) { 427 struct nlattr *nest; 428 429 nest = nla_nest_start(inst->skb, NFULA_VLAN); 430 if (!nest) 431 goto nla_put_failure; 432 433 if (nla_put_be16(inst->skb, NFULA_VLAN_TCI, htons(skb->vlan_tci)) || 434 nla_put_be16(inst->skb, NFULA_VLAN_PROTO, skb->vlan_proto)) 435 goto nla_put_failure; 436 437 nla_nest_end(inst->skb, nest); 438 } 439 440 if (skb->mac_header < skb->network_header) { 441 int len = (int)(skb->network_header - skb->mac_header); 442 443 if (nla_put(inst->skb, NFULA_L2HDR, len, skb_mac_header(skb))) 444 goto nla_put_failure; 445 } 446 447 return 0; 448 449 nla_put_failure: 450 return -1; 451 } 452 453 /* This is an inline function, we don't really care about a long 454 * list of arguments */ 455 static inline int 456 __build_packet_message(struct nfnl_log_net *log, 457 struct nfulnl_instance *inst, 458 const struct sk_buff *skb, 459 unsigned int data_len, 460 u_int8_t pf, 461 unsigned int hooknum, 462 const struct net_device *indev, 463 const struct net_device *outdev, 464 const char *prefix, unsigned int plen, 465 const struct nfnl_ct_hook *nfnl_ct, 466 struct nf_conn *ct, enum ip_conntrack_info ctinfo) 467 { 468 struct nfulnl_msg_packet_hdr pmsg; 469 struct nlmsghdr *nlh; 470 sk_buff_data_t old_tail = inst->skb->tail; 471 struct sock *sk; 472 const unsigned char *hwhdrp; 473 ktime_t tstamp; 474 475 nlh = nfnl_msg_put(inst->skb, 0, 0, 476 nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET), 477 0, pf, NFNETLINK_V0, htons(inst->group_num)); 478 if (!nlh) 479 return -1; 480 481 memset(&pmsg, 0, sizeof(pmsg)); 482 pmsg.hw_protocol = skb->protocol; 483 pmsg.hook = hooknum; 484 485 if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg)) 486 goto nla_put_failure; 487 488 if (prefix && 489 nla_put(inst->skb, NFULA_PREFIX, plen, prefix)) 490 goto nla_put_failure; 491 492 if (indev) { 493 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 494 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 495 htonl(indev->ifindex))) 496 goto nla_put_failure; 497 #else 498 if (pf == PF_BRIDGE) { 499 /* Case 1: outdev is physical input device, we need to 500 * look for bridge group (when called from 501 * netfilter_bridge) */ 502 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV, 503 htonl(indev->ifindex)) || 504 /* this is the bridge group "brX" */ 505 /* rcu_read_lock()ed by nf_hook_thresh or 506 * nf_log_packet. 507 */ 508 nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 509 htonl(br_port_get_rcu(indev)->br->dev->ifindex))) 510 goto nla_put_failure; 511 } else { 512 struct net_device *physindev; 513 514 /* Case 2: indev is bridge group, we need to look for 515 * physical device (when called from ipv4) */ 516 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 517 htonl(indev->ifindex))) 518 goto nla_put_failure; 519 520 physindev = nf_bridge_get_physindev(skb); 521 if (physindev && 522 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV, 523 htonl(physindev->ifindex))) 524 goto nla_put_failure; 525 } 526 #endif 527 } 528 529 if (outdev) { 530 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 531 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 532 htonl(outdev->ifindex))) 533 goto nla_put_failure; 534 #else 535 if (pf == PF_BRIDGE) { 536 /* Case 1: outdev is physical output device, we need to 537 * look for bridge group (when called from 538 * netfilter_bridge) */ 539 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV, 540 htonl(outdev->ifindex)) || 541 /* this is the bridge group "brX" */ 542 /* rcu_read_lock()ed by nf_hook_thresh or 543 * nf_log_packet. 544 */ 545 nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 546 htonl(br_port_get_rcu(outdev)->br->dev->ifindex))) 547 goto nla_put_failure; 548 } else { 549 struct net_device *physoutdev; 550 551 /* Case 2: indev is a bridge group, we need to look 552 * for physical device (when called from ipv4) */ 553 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 554 htonl(outdev->ifindex))) 555 goto nla_put_failure; 556 557 physoutdev = nf_bridge_get_physoutdev(skb); 558 if (physoutdev && 559 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV, 560 htonl(physoutdev->ifindex))) 561 goto nla_put_failure; 562 } 563 #endif 564 } 565 566 if (skb->mark && 567 nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark))) 568 goto nla_put_failure; 569 570 if (indev && skb->dev && 571 skb_mac_header_was_set(skb) && 572 skb_mac_header_len(skb) != 0) { 573 struct nfulnl_msg_packet_hw phw; 574 int len; 575 576 memset(&phw, 0, sizeof(phw)); 577 len = dev_parse_header(skb, phw.hw_addr); 578 if (len > 0) { 579 phw.hw_addrlen = htons(len); 580 if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw)) 581 goto nla_put_failure; 582 } 583 } 584 585 if (indev && skb_mac_header_was_set(skb)) { 586 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) || 587 nla_put_be16(inst->skb, NFULA_HWLEN, 588 htons(skb->dev->hard_header_len))) 589 goto nla_put_failure; 590 591 hwhdrp = skb_mac_header(skb); 592 593 if (skb->dev->type == ARPHRD_SIT) 594 hwhdrp -= ETH_HLEN; 595 596 if (hwhdrp >= skb->head && 597 nla_put(inst->skb, NFULA_HWHEADER, 598 skb->dev->hard_header_len, hwhdrp)) 599 goto nla_put_failure; 600 } 601 602 tstamp = skb_tstamp_cond(skb, false); 603 if (hooknum <= NF_INET_FORWARD && tstamp) { 604 struct nfulnl_msg_packet_timestamp ts; 605 struct timespec64 kts = ktime_to_timespec64(tstamp); 606 ts.sec = cpu_to_be64(kts.tv_sec); 607 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC); 608 609 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts)) 610 goto nla_put_failure; 611 } 612 613 /* UID */ 614 sk = skb->sk; 615 if (sk && sk_fullsock(sk)) { 616 read_lock_bh(&sk->sk_callback_lock); 617 if (sk->sk_socket && sk->sk_socket->file) { 618 struct file *file = sk->sk_socket->file; 619 const struct cred *cred = file->f_cred; 620 struct user_namespace *user_ns = inst->peer_user_ns; 621 __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid)); 622 __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid)); 623 read_unlock_bh(&sk->sk_callback_lock); 624 if (nla_put_be32(inst->skb, NFULA_UID, uid) || 625 nla_put_be32(inst->skb, NFULA_GID, gid)) 626 goto nla_put_failure; 627 } else 628 read_unlock_bh(&sk->sk_callback_lock); 629 } 630 631 /* local sequence number */ 632 if ((inst->flags & NFULNL_CFG_F_SEQ) && 633 nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++))) 634 goto nla_put_failure; 635 636 /* global sequence number */ 637 if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) && 638 nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL, 639 htonl(atomic_inc_return(&log->global_seq)))) 640 goto nla_put_failure; 641 642 if (ct && nfnl_ct->build(inst->skb, ct, ctinfo, 643 NFULA_CT, NFULA_CT_INFO) < 0) 644 goto nla_put_failure; 645 646 if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) && 647 nfulnl_put_bridge(inst, skb) < 0) 648 goto nla_put_failure; 649 650 if (data_len) { 651 struct nlattr *nla; 652 int size = nla_attr_size(data_len); 653 654 if (skb_tailroom(inst->skb) < nla_total_size(data_len)) 655 goto nla_put_failure; 656 657 nla = skb_put(inst->skb, nla_total_size(data_len)); 658 nla->nla_type = NFULA_PAYLOAD; 659 nla->nla_len = size; 660 661 if (skb_copy_bits(skb, 0, nla_data(nla), data_len)) 662 BUG(); 663 } 664 665 nlh->nlmsg_len = inst->skb->tail - old_tail; 666 return 0; 667 668 nla_put_failure: 669 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n"); 670 return -1; 671 } 672 673 static const struct nf_loginfo default_loginfo = { 674 .type = NF_LOG_TYPE_ULOG, 675 .u = { 676 .ulog = { 677 .copy_len = 0xffff, 678 .group = 0, 679 .qthreshold = 1, 680 }, 681 }, 682 }; 683 684 /* log handler for internal netfilter logging api */ 685 static void 686 nfulnl_log_packet(struct net *net, 687 u_int8_t pf, 688 unsigned int hooknum, 689 const struct sk_buff *skb, 690 const struct net_device *in, 691 const struct net_device *out, 692 const struct nf_loginfo *li_user, 693 const char *prefix) 694 { 695 size_t size; 696 unsigned int data_len; 697 struct nfulnl_instance *inst; 698 const struct nf_loginfo *li; 699 unsigned int qthreshold; 700 unsigned int plen = 0; 701 struct nfnl_log_net *log = nfnl_log_pernet(net); 702 const struct nfnl_ct_hook *nfnl_ct = NULL; 703 struct nf_conn *ct = NULL; 704 enum ip_conntrack_info ctinfo; 705 706 if (li_user && li_user->type == NF_LOG_TYPE_ULOG) 707 li = li_user; 708 else 709 li = &default_loginfo; 710 711 inst = instance_lookup_get_rcu(log, li->u.ulog.group); 712 if (!inst) 713 return; 714 715 if (prefix) 716 plen = strlen(prefix) + 1; 717 718 /* FIXME: do we want to make the size calculation conditional based on 719 * what is actually present? way more branches and checks, but more 720 * memory efficient... */ 721 size = nlmsg_total_size(sizeof(struct nfgenmsg)) 722 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr)) 723 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 724 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 725 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 726 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 727 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 728 #endif 729 + nla_total_size(sizeof(u_int32_t)) /* mark */ 730 + nla_total_size(sizeof(u_int32_t)) /* uid */ 731 + nla_total_size(sizeof(u_int32_t)) /* gid */ 732 + nla_total_size(plen) /* prefix */ 733 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw)) 734 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp)) 735 + nla_total_size(sizeof(struct nfgenmsg)); /* NLMSG_DONE */ 736 737 if (in && skb_mac_header_was_set(skb)) { 738 size += nla_total_size(skb->dev->hard_header_len) 739 + nla_total_size(sizeof(u_int16_t)) /* hwtype */ 740 + nla_total_size(sizeof(u_int16_t)); /* hwlen */ 741 } 742 743 spin_lock_bh(&inst->lock); 744 745 if (inst->flags & NFULNL_CFG_F_SEQ) 746 size += nla_total_size(sizeof(u_int32_t)); 747 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) 748 size += nla_total_size(sizeof(u_int32_t)); 749 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 750 if (inst->flags & NFULNL_CFG_F_CONNTRACK) { 751 nfnl_ct = rcu_dereference(nfnl_ct_hook); 752 if (nfnl_ct != NULL) { 753 ct = nf_ct_get(skb, &ctinfo); 754 if (ct != NULL) 755 size += nfnl_ct->build_size(ct); 756 } 757 } 758 #endif 759 if (pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) 760 size += nfulnl_get_bridge_size(skb); 761 762 qthreshold = inst->qthreshold; 763 /* per-rule qthreshold overrides per-instance */ 764 if (li->u.ulog.qthreshold) 765 if (qthreshold > li->u.ulog.qthreshold) 766 qthreshold = li->u.ulog.qthreshold; 767 768 769 switch (inst->copy_mode) { 770 case NFULNL_COPY_META: 771 case NFULNL_COPY_NONE: 772 data_len = 0; 773 break; 774 775 case NFULNL_COPY_PACKET: 776 data_len = inst->copy_range; 777 if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) && 778 (li->u.ulog.copy_len < data_len)) 779 data_len = li->u.ulog.copy_len; 780 781 if (data_len > skb->len) 782 data_len = skb->len; 783 784 size += nla_total_size(data_len); 785 break; 786 787 case NFULNL_COPY_DISABLED: 788 default: 789 goto unlock_and_release; 790 } 791 792 if (inst->skb && size > skb_tailroom(inst->skb)) { 793 /* either the queue len is too high or we don't have 794 * enough room in the skb left. flush to userspace. */ 795 __nfulnl_flush(inst); 796 } 797 798 if (!inst->skb) { 799 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid, 800 inst->nlbufsiz, size); 801 if (!inst->skb) 802 goto alloc_failure; 803 } 804 805 inst->qlen++; 806 807 __build_packet_message(log, inst, skb, data_len, pf, 808 hooknum, in, out, prefix, plen, 809 nfnl_ct, ct, ctinfo); 810 811 if (inst->qlen >= qthreshold) 812 __nfulnl_flush(inst); 813 /* timer_pending always called within inst->lock, so there 814 * is no chance of a race here */ 815 else if (!timer_pending(&inst->timer)) { 816 instance_get(inst); 817 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100); 818 add_timer(&inst->timer); 819 } 820 821 unlock_and_release: 822 spin_unlock_bh(&inst->lock); 823 instance_put(inst); 824 return; 825 826 alloc_failure: 827 /* FIXME: statistics */ 828 goto unlock_and_release; 829 } 830 831 static int 832 nfulnl_rcv_nl_event(struct notifier_block *this, 833 unsigned long event, void *ptr) 834 { 835 struct netlink_notify *n = ptr; 836 struct nfnl_log_net *log = nfnl_log_pernet(n->net); 837 838 if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) { 839 int i; 840 841 /* destroy all instances for this portid */ 842 spin_lock_bh(&log->instances_lock); 843 for (i = 0; i < INSTANCE_BUCKETS; i++) { 844 struct hlist_node *t2; 845 struct nfulnl_instance *inst; 846 struct hlist_head *head = &log->instance_table[i]; 847 848 hlist_for_each_entry_safe(inst, t2, head, hlist) { 849 if (n->portid == inst->peer_portid) 850 __instance_destroy(inst); 851 } 852 } 853 spin_unlock_bh(&log->instances_lock); 854 } 855 return NOTIFY_DONE; 856 } 857 858 static struct notifier_block nfulnl_rtnl_notifier = { 859 .notifier_call = nfulnl_rcv_nl_event, 860 }; 861 862 static int nfulnl_recv_unsupp(struct sk_buff *skb, const struct nfnl_info *info, 863 const struct nlattr * const nfula[]) 864 { 865 return -ENOTSUPP; 866 } 867 868 static struct nf_logger nfulnl_logger __read_mostly = { 869 .name = "nfnetlink_log", 870 .type = NF_LOG_TYPE_ULOG, 871 .logfn = nfulnl_log_packet, 872 .me = THIS_MODULE, 873 }; 874 875 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = { 876 [NFULA_CFG_CMD] = { .len = sizeof(struct nfulnl_msg_config_cmd) }, 877 [NFULA_CFG_MODE] = { .len = sizeof(struct nfulnl_msg_config_mode) }, 878 [NFULA_CFG_TIMEOUT] = { .type = NLA_U32 }, 879 [NFULA_CFG_QTHRESH] = { .type = NLA_U32 }, 880 [NFULA_CFG_NLBUFSIZ] = { .type = NLA_U32 }, 881 [NFULA_CFG_FLAGS] = { .type = NLA_U16 }, 882 }; 883 884 static int nfulnl_recv_config(struct sk_buff *skb, const struct nfnl_info *info, 885 const struct nlattr * const nfula[]) 886 { 887 struct nfnl_log_net *log = nfnl_log_pernet(info->net); 888 u_int16_t group_num = ntohs(info->nfmsg->res_id); 889 struct nfulnl_msg_config_cmd *cmd = NULL; 890 struct nfulnl_instance *inst; 891 u16 flags = 0; 892 int ret = 0; 893 894 if (nfula[NFULA_CFG_CMD]) { 895 u_int8_t pf = info->nfmsg->nfgen_family; 896 cmd = nla_data(nfula[NFULA_CFG_CMD]); 897 898 /* Commands without queue context */ 899 switch (cmd->command) { 900 case NFULNL_CFG_CMD_PF_BIND: 901 return nf_log_bind_pf(info->net, pf, &nfulnl_logger); 902 case NFULNL_CFG_CMD_PF_UNBIND: 903 nf_log_unbind_pf(info->net, pf); 904 return 0; 905 } 906 } 907 908 inst = instance_lookup_get(log, group_num); 909 if (inst && inst->peer_portid != NETLINK_CB(skb).portid) { 910 ret = -EPERM; 911 goto out_put; 912 } 913 914 /* Check if we support these flags in first place, dependencies should 915 * be there too not to break atomicity. 916 */ 917 if (nfula[NFULA_CFG_FLAGS]) { 918 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS])); 919 920 if ((flags & NFULNL_CFG_F_CONNTRACK) && 921 !rcu_access_pointer(nfnl_ct_hook)) { 922 #ifdef CONFIG_MODULES 923 nfnl_unlock(NFNL_SUBSYS_ULOG); 924 request_module("ip_conntrack_netlink"); 925 nfnl_lock(NFNL_SUBSYS_ULOG); 926 if (rcu_access_pointer(nfnl_ct_hook)) { 927 ret = -EAGAIN; 928 goto out_put; 929 } 930 #endif 931 ret = -EOPNOTSUPP; 932 goto out_put; 933 } 934 } 935 936 if (cmd != NULL) { 937 switch (cmd->command) { 938 case NFULNL_CFG_CMD_BIND: 939 if (inst) { 940 ret = -EBUSY; 941 goto out_put; 942 } 943 944 inst = instance_create(info->net, group_num, 945 NETLINK_CB(skb).portid, 946 sk_user_ns(NETLINK_CB(skb).sk)); 947 if (IS_ERR(inst)) { 948 ret = PTR_ERR(inst); 949 goto out; 950 } 951 break; 952 case NFULNL_CFG_CMD_UNBIND: 953 if (!inst) { 954 ret = -ENODEV; 955 goto out; 956 } 957 958 instance_destroy(log, inst); 959 goto out_put; 960 default: 961 ret = -ENOTSUPP; 962 goto out_put; 963 } 964 } else if (!inst) { 965 ret = -ENODEV; 966 goto out; 967 } 968 969 if (nfula[NFULA_CFG_MODE]) { 970 struct nfulnl_msg_config_mode *params = 971 nla_data(nfula[NFULA_CFG_MODE]); 972 973 nfulnl_set_mode(inst, params->copy_mode, 974 ntohl(params->copy_range)); 975 } 976 977 if (nfula[NFULA_CFG_TIMEOUT]) { 978 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]); 979 980 nfulnl_set_timeout(inst, ntohl(timeout)); 981 } 982 983 if (nfula[NFULA_CFG_NLBUFSIZ]) { 984 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]); 985 986 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz)); 987 } 988 989 if (nfula[NFULA_CFG_QTHRESH]) { 990 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]); 991 992 nfulnl_set_qthresh(inst, ntohl(qthresh)); 993 } 994 995 if (nfula[NFULA_CFG_FLAGS]) 996 nfulnl_set_flags(inst, flags); 997 998 out_put: 999 instance_put(inst); 1000 out: 1001 return ret; 1002 } 1003 1004 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = { 1005 [NFULNL_MSG_PACKET] = { 1006 .call = nfulnl_recv_unsupp, 1007 .type = NFNL_CB_MUTEX, 1008 .attr_count = NFULA_MAX, 1009 }, 1010 [NFULNL_MSG_CONFIG] = { 1011 .call = nfulnl_recv_config, 1012 .type = NFNL_CB_MUTEX, 1013 .attr_count = NFULA_CFG_MAX, 1014 .policy = nfula_cfg_policy 1015 }, 1016 }; 1017 1018 static const struct nfnetlink_subsystem nfulnl_subsys = { 1019 .name = "log", 1020 .subsys_id = NFNL_SUBSYS_ULOG, 1021 .cb_count = NFULNL_MSG_MAX, 1022 .cb = nfulnl_cb, 1023 }; 1024 1025 #ifdef CONFIG_PROC_FS 1026 struct iter_state { 1027 struct seq_net_private p; 1028 unsigned int bucket; 1029 }; 1030 1031 static struct hlist_node *get_first(struct net *net, struct iter_state *st) 1032 { 1033 struct nfnl_log_net *log; 1034 if (!st) 1035 return NULL; 1036 1037 log = nfnl_log_pernet(net); 1038 1039 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) { 1040 struct hlist_head *head = &log->instance_table[st->bucket]; 1041 1042 if (!hlist_empty(head)) 1043 return rcu_dereference(hlist_first_rcu(head)); 1044 } 1045 return NULL; 1046 } 1047 1048 static struct hlist_node *get_next(struct net *net, struct iter_state *st, 1049 struct hlist_node *h) 1050 { 1051 h = rcu_dereference(hlist_next_rcu(h)); 1052 while (!h) { 1053 struct nfnl_log_net *log; 1054 struct hlist_head *head; 1055 1056 if (++st->bucket >= INSTANCE_BUCKETS) 1057 return NULL; 1058 1059 log = nfnl_log_pernet(net); 1060 head = &log->instance_table[st->bucket]; 1061 h = rcu_dereference(hlist_first_rcu(head)); 1062 } 1063 return h; 1064 } 1065 1066 static struct hlist_node *get_idx(struct net *net, struct iter_state *st, 1067 loff_t pos) 1068 { 1069 struct hlist_node *head; 1070 head = get_first(net, st); 1071 1072 if (head) 1073 while (pos && (head = get_next(net, st, head))) 1074 pos--; 1075 return pos ? NULL : head; 1076 } 1077 1078 static void *seq_start(struct seq_file *s, loff_t *pos) 1079 __acquires(rcu) 1080 { 1081 rcu_read_lock(); 1082 return get_idx(seq_file_net(s), s->private, *pos); 1083 } 1084 1085 static void *seq_next(struct seq_file *s, void *v, loff_t *pos) 1086 { 1087 (*pos)++; 1088 return get_next(seq_file_net(s), s->private, v); 1089 } 1090 1091 static void seq_stop(struct seq_file *s, void *v) 1092 __releases(rcu) 1093 { 1094 rcu_read_unlock(); 1095 } 1096 1097 static int seq_show(struct seq_file *s, void *v) 1098 { 1099 const struct nfulnl_instance *inst = v; 1100 1101 seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n", 1102 inst->group_num, 1103 inst->peer_portid, inst->qlen, 1104 inst->copy_mode, inst->copy_range, 1105 inst->flushtimeout, refcount_read(&inst->use)); 1106 1107 return 0; 1108 } 1109 1110 static const struct seq_operations nful_seq_ops = { 1111 .start = seq_start, 1112 .next = seq_next, 1113 .stop = seq_stop, 1114 .show = seq_show, 1115 }; 1116 #endif /* PROC_FS */ 1117 1118 static int __net_init nfnl_log_net_init(struct net *net) 1119 { 1120 unsigned int i; 1121 struct nfnl_log_net *log = nfnl_log_pernet(net); 1122 #ifdef CONFIG_PROC_FS 1123 struct proc_dir_entry *proc; 1124 kuid_t root_uid; 1125 kgid_t root_gid; 1126 #endif 1127 1128 for (i = 0; i < INSTANCE_BUCKETS; i++) 1129 INIT_HLIST_HEAD(&log->instance_table[i]); 1130 spin_lock_init(&log->instances_lock); 1131 1132 #ifdef CONFIG_PROC_FS 1133 proc = proc_create_net("nfnetlink_log", 0440, net->nf.proc_netfilter, 1134 &nful_seq_ops, sizeof(struct iter_state)); 1135 if (!proc) 1136 return -ENOMEM; 1137 1138 root_uid = make_kuid(net->user_ns, 0); 1139 root_gid = make_kgid(net->user_ns, 0); 1140 if (uid_valid(root_uid) && gid_valid(root_gid)) 1141 proc_set_user(proc, root_uid, root_gid); 1142 #endif 1143 return 0; 1144 } 1145 1146 static void __net_exit nfnl_log_net_exit(struct net *net) 1147 { 1148 struct nfnl_log_net *log = nfnl_log_pernet(net); 1149 unsigned int i; 1150 1151 #ifdef CONFIG_PROC_FS 1152 remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter); 1153 #endif 1154 nf_log_unset(net, &nfulnl_logger); 1155 for (i = 0; i < INSTANCE_BUCKETS; i++) 1156 WARN_ON_ONCE(!hlist_empty(&log->instance_table[i])); 1157 } 1158 1159 static struct pernet_operations nfnl_log_net_ops = { 1160 .init = nfnl_log_net_init, 1161 .exit = nfnl_log_net_exit, 1162 .id = &nfnl_log_net_id, 1163 .size = sizeof(struct nfnl_log_net), 1164 }; 1165 1166 static int __init nfnetlink_log_init(void) 1167 { 1168 int status; 1169 1170 status = register_pernet_subsys(&nfnl_log_net_ops); 1171 if (status < 0) { 1172 pr_err("failed to register pernet ops\n"); 1173 goto out; 1174 } 1175 1176 netlink_register_notifier(&nfulnl_rtnl_notifier); 1177 status = nfnetlink_subsys_register(&nfulnl_subsys); 1178 if (status < 0) { 1179 pr_err("failed to create netlink socket\n"); 1180 goto cleanup_netlink_notifier; 1181 } 1182 1183 status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger); 1184 if (status < 0) { 1185 pr_err("failed to register logger\n"); 1186 goto cleanup_subsys; 1187 } 1188 1189 return status; 1190 1191 cleanup_subsys: 1192 nfnetlink_subsys_unregister(&nfulnl_subsys); 1193 cleanup_netlink_notifier: 1194 netlink_unregister_notifier(&nfulnl_rtnl_notifier); 1195 unregister_pernet_subsys(&nfnl_log_net_ops); 1196 out: 1197 return status; 1198 } 1199 1200 static void __exit nfnetlink_log_fini(void) 1201 { 1202 nfnetlink_subsys_unregister(&nfulnl_subsys); 1203 netlink_unregister_notifier(&nfulnl_rtnl_notifier); 1204 unregister_pernet_subsys(&nfnl_log_net_ops); 1205 nf_log_unregister(&nfulnl_logger); 1206 } 1207 1208 MODULE_DESCRIPTION("netfilter userspace logging"); 1209 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); 1210 MODULE_LICENSE("GPL"); 1211 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG); 1212 MODULE_ALIAS_NF_LOGGER(AF_INET, 1); 1213 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1); 1214 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1); 1215 MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */ 1216 MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */ 1217 1218 module_init(nfnetlink_log_init); 1219 module_exit(nfnetlink_log_fini); 1220