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; 473 474 nlh = nfnl_msg_put(inst->skb, 0, 0, 475 nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET), 476 0, pf, NFNETLINK_V0, htons(inst->group_num)); 477 if (!nlh) 478 return -1; 479 480 memset(&pmsg, 0, sizeof(pmsg)); 481 pmsg.hw_protocol = skb->protocol; 482 pmsg.hook = hooknum; 483 484 if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg)) 485 goto nla_put_failure; 486 487 if (prefix && 488 nla_put(inst->skb, NFULA_PREFIX, plen, prefix)) 489 goto nla_put_failure; 490 491 if (indev) { 492 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 493 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 494 htonl(indev->ifindex))) 495 goto nla_put_failure; 496 #else 497 if (pf == PF_BRIDGE) { 498 /* Case 1: outdev is physical input device, we need to 499 * look for bridge group (when called from 500 * netfilter_bridge) */ 501 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV, 502 htonl(indev->ifindex)) || 503 /* this is the bridge group "brX" */ 504 /* rcu_read_lock()ed by nf_hook_thresh or 505 * nf_log_packet. 506 */ 507 nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 508 htonl(br_port_get_rcu(indev)->br->dev->ifindex))) 509 goto nla_put_failure; 510 } else { 511 struct net_device *physindev; 512 513 /* Case 2: indev is bridge group, we need to look for 514 * physical device (when called from ipv4) */ 515 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 516 htonl(indev->ifindex))) 517 goto nla_put_failure; 518 519 physindev = nf_bridge_get_physindev(skb); 520 if (physindev && 521 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV, 522 htonl(physindev->ifindex))) 523 goto nla_put_failure; 524 } 525 #endif 526 } 527 528 if (outdev) { 529 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 530 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 531 htonl(outdev->ifindex))) 532 goto nla_put_failure; 533 #else 534 if (pf == PF_BRIDGE) { 535 /* Case 1: outdev is physical output device, we need to 536 * look for bridge group (when called from 537 * netfilter_bridge) */ 538 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV, 539 htonl(outdev->ifindex)) || 540 /* this is the bridge group "brX" */ 541 /* rcu_read_lock()ed by nf_hook_thresh or 542 * nf_log_packet. 543 */ 544 nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 545 htonl(br_port_get_rcu(outdev)->br->dev->ifindex))) 546 goto nla_put_failure; 547 } else { 548 struct net_device *physoutdev; 549 550 /* Case 2: indev is a bridge group, we need to look 551 * for physical device (when called from ipv4) */ 552 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 553 htonl(outdev->ifindex))) 554 goto nla_put_failure; 555 556 physoutdev = nf_bridge_get_physoutdev(skb); 557 if (physoutdev && 558 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV, 559 htonl(physoutdev->ifindex))) 560 goto nla_put_failure; 561 } 562 #endif 563 } 564 565 if (skb->mark && 566 nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark))) 567 goto nla_put_failure; 568 569 if (indev && skb->dev && 570 skb_mac_header_was_set(skb) && 571 skb_mac_header_len(skb) != 0) { 572 struct nfulnl_msg_packet_hw phw; 573 int len; 574 575 memset(&phw, 0, sizeof(phw)); 576 len = dev_parse_header(skb, phw.hw_addr); 577 if (len > 0) { 578 phw.hw_addrlen = htons(len); 579 if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw)) 580 goto nla_put_failure; 581 } 582 } 583 584 if (indev && skb_mac_header_was_set(skb)) { 585 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) || 586 nla_put_be16(inst->skb, NFULA_HWLEN, 587 htons(skb->dev->hard_header_len))) 588 goto nla_put_failure; 589 590 hwhdrp = skb_mac_header(skb); 591 592 if (skb->dev->type == ARPHRD_SIT) 593 hwhdrp -= ETH_HLEN; 594 595 if (hwhdrp >= skb->head && 596 nla_put(inst->skb, NFULA_HWHEADER, 597 skb->dev->hard_header_len, hwhdrp)) 598 goto nla_put_failure; 599 } 600 601 if (hooknum <= NF_INET_FORWARD) { 602 struct timespec64 kts = ktime_to_timespec64(skb_tstamp_cond(skb, true)); 603 struct nfulnl_msg_packet_timestamp ts; 604 ts.sec = cpu_to_be64(kts.tv_sec); 605 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC); 606 607 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts)) 608 goto nla_put_failure; 609 } 610 611 /* UID */ 612 sk = skb->sk; 613 if (sk && sk_fullsock(sk)) { 614 read_lock_bh(&sk->sk_callback_lock); 615 if (sk->sk_socket && sk->sk_socket->file) { 616 struct file *file = sk->sk_socket->file; 617 const struct cred *cred = file->f_cred; 618 struct user_namespace *user_ns = inst->peer_user_ns; 619 __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid)); 620 __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid)); 621 read_unlock_bh(&sk->sk_callback_lock); 622 if (nla_put_be32(inst->skb, NFULA_UID, uid) || 623 nla_put_be32(inst->skb, NFULA_GID, gid)) 624 goto nla_put_failure; 625 } else 626 read_unlock_bh(&sk->sk_callback_lock); 627 } 628 629 /* local sequence number */ 630 if ((inst->flags & NFULNL_CFG_F_SEQ) && 631 nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++))) 632 goto nla_put_failure; 633 634 /* global sequence number */ 635 if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) && 636 nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL, 637 htonl(atomic_inc_return(&log->global_seq)))) 638 goto nla_put_failure; 639 640 if (ct && nfnl_ct->build(inst->skb, ct, ctinfo, 641 NFULA_CT, NFULA_CT_INFO) < 0) 642 goto nla_put_failure; 643 644 if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) && 645 nfulnl_put_bridge(inst, skb) < 0) 646 goto nla_put_failure; 647 648 if (data_len) { 649 struct nlattr *nla; 650 int size = nla_attr_size(data_len); 651 652 if (skb_tailroom(inst->skb) < nla_total_size(data_len)) 653 goto nla_put_failure; 654 655 nla = skb_put(inst->skb, nla_total_size(data_len)); 656 nla->nla_type = NFULA_PAYLOAD; 657 nla->nla_len = size; 658 659 if (skb_copy_bits(skb, 0, nla_data(nla), data_len)) 660 BUG(); 661 } 662 663 nlh->nlmsg_len = inst->skb->tail - old_tail; 664 return 0; 665 666 nla_put_failure: 667 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n"); 668 return -1; 669 } 670 671 static const struct nf_loginfo default_loginfo = { 672 .type = NF_LOG_TYPE_ULOG, 673 .u = { 674 .ulog = { 675 .copy_len = 0xffff, 676 .group = 0, 677 .qthreshold = 1, 678 }, 679 }, 680 }; 681 682 /* log handler for internal netfilter logging api */ 683 static void 684 nfulnl_log_packet(struct net *net, 685 u_int8_t pf, 686 unsigned int hooknum, 687 const struct sk_buff *skb, 688 const struct net_device *in, 689 const struct net_device *out, 690 const struct nf_loginfo *li_user, 691 const char *prefix) 692 { 693 size_t size; 694 unsigned int data_len; 695 struct nfulnl_instance *inst; 696 const struct nf_loginfo *li; 697 unsigned int qthreshold; 698 unsigned int plen = 0; 699 struct nfnl_log_net *log = nfnl_log_pernet(net); 700 const struct nfnl_ct_hook *nfnl_ct = NULL; 701 enum ip_conntrack_info ctinfo = 0; 702 struct nf_conn *ct = NULL; 703 704 if (li_user && li_user->type == NF_LOG_TYPE_ULOG) 705 li = li_user; 706 else 707 li = &default_loginfo; 708 709 inst = instance_lookup_get_rcu(log, li->u.ulog.group); 710 if (!inst) 711 return; 712 713 if (prefix) 714 plen = strlen(prefix) + 1; 715 716 /* FIXME: do we want to make the size calculation conditional based on 717 * what is actually present? way more branches and checks, but more 718 * memory efficient... */ 719 size = nlmsg_total_size(sizeof(struct nfgenmsg)) 720 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr)) 721 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 722 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 723 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 724 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 725 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 726 #endif 727 + nla_total_size(sizeof(u_int32_t)) /* mark */ 728 + nla_total_size(sizeof(u_int32_t)) /* uid */ 729 + nla_total_size(sizeof(u_int32_t)) /* gid */ 730 + nla_total_size(plen) /* prefix */ 731 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw)) 732 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp)) 733 + nla_total_size(sizeof(struct nfgenmsg)); /* NLMSG_DONE */ 734 735 if (in && skb_mac_header_was_set(skb)) { 736 size += nla_total_size(skb->dev->hard_header_len) 737 + nla_total_size(sizeof(u_int16_t)) /* hwtype */ 738 + nla_total_size(sizeof(u_int16_t)); /* hwlen */ 739 } 740 741 spin_lock_bh(&inst->lock); 742 743 if (inst->flags & NFULNL_CFG_F_SEQ) 744 size += nla_total_size(sizeof(u_int32_t)); 745 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) 746 size += nla_total_size(sizeof(u_int32_t)); 747 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 748 if (inst->flags & NFULNL_CFG_F_CONNTRACK) { 749 nfnl_ct = rcu_dereference(nfnl_ct_hook); 750 if (nfnl_ct != NULL) { 751 ct = nf_ct_get(skb, &ctinfo); 752 if (ct != NULL) 753 size += nfnl_ct->build_size(ct); 754 } 755 } 756 #endif 757 if (pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) 758 size += nfulnl_get_bridge_size(skb); 759 760 qthreshold = inst->qthreshold; 761 /* per-rule qthreshold overrides per-instance */ 762 if (li->u.ulog.qthreshold) 763 if (qthreshold > li->u.ulog.qthreshold) 764 qthreshold = li->u.ulog.qthreshold; 765 766 767 switch (inst->copy_mode) { 768 case NFULNL_COPY_META: 769 case NFULNL_COPY_NONE: 770 data_len = 0; 771 break; 772 773 case NFULNL_COPY_PACKET: 774 data_len = inst->copy_range; 775 if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) && 776 (li->u.ulog.copy_len < data_len)) 777 data_len = li->u.ulog.copy_len; 778 779 if (data_len > skb->len) 780 data_len = skb->len; 781 782 size += nla_total_size(data_len); 783 break; 784 785 case NFULNL_COPY_DISABLED: 786 default: 787 goto unlock_and_release; 788 } 789 790 if (inst->skb && size > skb_tailroom(inst->skb)) { 791 /* either the queue len is too high or we don't have 792 * enough room in the skb left. flush to userspace. */ 793 __nfulnl_flush(inst); 794 } 795 796 if (!inst->skb) { 797 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid, 798 inst->nlbufsiz, size); 799 if (!inst->skb) 800 goto alloc_failure; 801 } 802 803 inst->qlen++; 804 805 __build_packet_message(log, inst, skb, data_len, pf, 806 hooknum, in, out, prefix, plen, 807 nfnl_ct, ct, ctinfo); 808 809 if (inst->qlen >= qthreshold) 810 __nfulnl_flush(inst); 811 /* timer_pending always called within inst->lock, so there 812 * is no chance of a race here */ 813 else if (!timer_pending(&inst->timer)) { 814 instance_get(inst); 815 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100); 816 add_timer(&inst->timer); 817 } 818 819 unlock_and_release: 820 spin_unlock_bh(&inst->lock); 821 instance_put(inst); 822 return; 823 824 alloc_failure: 825 /* FIXME: statistics */ 826 goto unlock_and_release; 827 } 828 829 static int 830 nfulnl_rcv_nl_event(struct notifier_block *this, 831 unsigned long event, void *ptr) 832 { 833 struct netlink_notify *n = ptr; 834 struct nfnl_log_net *log = nfnl_log_pernet(n->net); 835 836 if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) { 837 int i; 838 839 /* destroy all instances for this portid */ 840 spin_lock_bh(&log->instances_lock); 841 for (i = 0; i < INSTANCE_BUCKETS; i++) { 842 struct hlist_node *t2; 843 struct nfulnl_instance *inst; 844 struct hlist_head *head = &log->instance_table[i]; 845 846 hlist_for_each_entry_safe(inst, t2, head, hlist) { 847 if (n->portid == inst->peer_portid) 848 __instance_destroy(inst); 849 } 850 } 851 spin_unlock_bh(&log->instances_lock); 852 } 853 return NOTIFY_DONE; 854 } 855 856 static struct notifier_block nfulnl_rtnl_notifier = { 857 .notifier_call = nfulnl_rcv_nl_event, 858 }; 859 860 static int nfulnl_recv_unsupp(struct sk_buff *skb, const struct nfnl_info *info, 861 const struct nlattr * const nfula[]) 862 { 863 return -ENOTSUPP; 864 } 865 866 static struct nf_logger nfulnl_logger __read_mostly = { 867 .name = "nfnetlink_log", 868 .type = NF_LOG_TYPE_ULOG, 869 .logfn = nfulnl_log_packet, 870 .me = THIS_MODULE, 871 }; 872 873 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = { 874 [NFULA_CFG_CMD] = { .len = sizeof(struct nfulnl_msg_config_cmd) }, 875 [NFULA_CFG_MODE] = { .len = sizeof(struct nfulnl_msg_config_mode) }, 876 [NFULA_CFG_TIMEOUT] = { .type = NLA_U32 }, 877 [NFULA_CFG_QTHRESH] = { .type = NLA_U32 }, 878 [NFULA_CFG_NLBUFSIZ] = { .type = NLA_U32 }, 879 [NFULA_CFG_FLAGS] = { .type = NLA_U16 }, 880 }; 881 882 static int nfulnl_recv_config(struct sk_buff *skb, const struct nfnl_info *info, 883 const struct nlattr * const nfula[]) 884 { 885 struct nfnl_log_net *log = nfnl_log_pernet(info->net); 886 u_int16_t group_num = ntohs(info->nfmsg->res_id); 887 struct nfulnl_msg_config_cmd *cmd = NULL; 888 struct nfulnl_instance *inst; 889 u16 flags = 0; 890 int ret = 0; 891 892 if (nfula[NFULA_CFG_CMD]) { 893 u_int8_t pf = info->nfmsg->nfgen_family; 894 cmd = nla_data(nfula[NFULA_CFG_CMD]); 895 896 /* Commands without queue context */ 897 switch (cmd->command) { 898 case NFULNL_CFG_CMD_PF_BIND: 899 return nf_log_bind_pf(info->net, pf, &nfulnl_logger); 900 case NFULNL_CFG_CMD_PF_UNBIND: 901 nf_log_unbind_pf(info->net, pf); 902 return 0; 903 } 904 } 905 906 inst = instance_lookup_get(log, group_num); 907 if (inst && inst->peer_portid != NETLINK_CB(skb).portid) { 908 ret = -EPERM; 909 goto out_put; 910 } 911 912 /* Check if we support these flags in first place, dependencies should 913 * be there too not to break atomicity. 914 */ 915 if (nfula[NFULA_CFG_FLAGS]) { 916 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS])); 917 918 if ((flags & NFULNL_CFG_F_CONNTRACK) && 919 !rcu_access_pointer(nfnl_ct_hook)) { 920 #ifdef CONFIG_MODULES 921 nfnl_unlock(NFNL_SUBSYS_ULOG); 922 request_module("ip_conntrack_netlink"); 923 nfnl_lock(NFNL_SUBSYS_ULOG); 924 if (rcu_access_pointer(nfnl_ct_hook)) { 925 ret = -EAGAIN; 926 goto out_put; 927 } 928 #endif 929 ret = -EOPNOTSUPP; 930 goto out_put; 931 } 932 } 933 934 if (cmd != NULL) { 935 switch (cmd->command) { 936 case NFULNL_CFG_CMD_BIND: 937 if (inst) { 938 ret = -EBUSY; 939 goto out_put; 940 } 941 942 inst = instance_create(info->net, group_num, 943 NETLINK_CB(skb).portid, 944 sk_user_ns(NETLINK_CB(skb).sk)); 945 if (IS_ERR(inst)) { 946 ret = PTR_ERR(inst); 947 goto out; 948 } 949 break; 950 case NFULNL_CFG_CMD_UNBIND: 951 if (!inst) { 952 ret = -ENODEV; 953 goto out; 954 } 955 956 instance_destroy(log, inst); 957 goto out_put; 958 default: 959 ret = -ENOTSUPP; 960 goto out_put; 961 } 962 } else if (!inst) { 963 ret = -ENODEV; 964 goto out; 965 } 966 967 if (nfula[NFULA_CFG_MODE]) { 968 struct nfulnl_msg_config_mode *params = 969 nla_data(nfula[NFULA_CFG_MODE]); 970 971 nfulnl_set_mode(inst, params->copy_mode, 972 ntohl(params->copy_range)); 973 } 974 975 if (nfula[NFULA_CFG_TIMEOUT]) { 976 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]); 977 978 nfulnl_set_timeout(inst, ntohl(timeout)); 979 } 980 981 if (nfula[NFULA_CFG_NLBUFSIZ]) { 982 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]); 983 984 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz)); 985 } 986 987 if (nfula[NFULA_CFG_QTHRESH]) { 988 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]); 989 990 nfulnl_set_qthresh(inst, ntohl(qthresh)); 991 } 992 993 if (nfula[NFULA_CFG_FLAGS]) 994 nfulnl_set_flags(inst, flags); 995 996 out_put: 997 instance_put(inst); 998 out: 999 return ret; 1000 } 1001 1002 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = { 1003 [NFULNL_MSG_PACKET] = { 1004 .call = nfulnl_recv_unsupp, 1005 .type = NFNL_CB_MUTEX, 1006 .attr_count = NFULA_MAX, 1007 }, 1008 [NFULNL_MSG_CONFIG] = { 1009 .call = nfulnl_recv_config, 1010 .type = NFNL_CB_MUTEX, 1011 .attr_count = NFULA_CFG_MAX, 1012 .policy = nfula_cfg_policy 1013 }, 1014 }; 1015 1016 static const struct nfnetlink_subsystem nfulnl_subsys = { 1017 .name = "log", 1018 .subsys_id = NFNL_SUBSYS_ULOG, 1019 .cb_count = NFULNL_MSG_MAX, 1020 .cb = nfulnl_cb, 1021 }; 1022 1023 #ifdef CONFIG_PROC_FS 1024 struct iter_state { 1025 struct seq_net_private p; 1026 unsigned int bucket; 1027 }; 1028 1029 static struct hlist_node *get_first(struct net *net, struct iter_state *st) 1030 { 1031 struct nfnl_log_net *log; 1032 if (!st) 1033 return NULL; 1034 1035 log = nfnl_log_pernet(net); 1036 1037 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) { 1038 struct hlist_head *head = &log->instance_table[st->bucket]; 1039 1040 if (!hlist_empty(head)) 1041 return rcu_dereference(hlist_first_rcu(head)); 1042 } 1043 return NULL; 1044 } 1045 1046 static struct hlist_node *get_next(struct net *net, struct iter_state *st, 1047 struct hlist_node *h) 1048 { 1049 h = rcu_dereference(hlist_next_rcu(h)); 1050 while (!h) { 1051 struct nfnl_log_net *log; 1052 struct hlist_head *head; 1053 1054 if (++st->bucket >= INSTANCE_BUCKETS) 1055 return NULL; 1056 1057 log = nfnl_log_pernet(net); 1058 head = &log->instance_table[st->bucket]; 1059 h = rcu_dereference(hlist_first_rcu(head)); 1060 } 1061 return h; 1062 } 1063 1064 static struct hlist_node *get_idx(struct net *net, struct iter_state *st, 1065 loff_t pos) 1066 { 1067 struct hlist_node *head; 1068 head = get_first(net, st); 1069 1070 if (head) 1071 while (pos && (head = get_next(net, st, head))) 1072 pos--; 1073 return pos ? NULL : head; 1074 } 1075 1076 static void *seq_start(struct seq_file *s, loff_t *pos) 1077 __acquires(rcu) 1078 { 1079 rcu_read_lock(); 1080 return get_idx(seq_file_net(s), s->private, *pos); 1081 } 1082 1083 static void *seq_next(struct seq_file *s, void *v, loff_t *pos) 1084 { 1085 (*pos)++; 1086 return get_next(seq_file_net(s), s->private, v); 1087 } 1088 1089 static void seq_stop(struct seq_file *s, void *v) 1090 __releases(rcu) 1091 { 1092 rcu_read_unlock(); 1093 } 1094 1095 static int seq_show(struct seq_file *s, void *v) 1096 { 1097 const struct nfulnl_instance *inst = v; 1098 1099 seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n", 1100 inst->group_num, 1101 inst->peer_portid, inst->qlen, 1102 inst->copy_mode, inst->copy_range, 1103 inst->flushtimeout, refcount_read(&inst->use)); 1104 1105 return 0; 1106 } 1107 1108 static const struct seq_operations nful_seq_ops = { 1109 .start = seq_start, 1110 .next = seq_next, 1111 .stop = seq_stop, 1112 .show = seq_show, 1113 }; 1114 #endif /* PROC_FS */ 1115 1116 static int __net_init nfnl_log_net_init(struct net *net) 1117 { 1118 unsigned int i; 1119 struct nfnl_log_net *log = nfnl_log_pernet(net); 1120 #ifdef CONFIG_PROC_FS 1121 struct proc_dir_entry *proc; 1122 kuid_t root_uid; 1123 kgid_t root_gid; 1124 #endif 1125 1126 for (i = 0; i < INSTANCE_BUCKETS; i++) 1127 INIT_HLIST_HEAD(&log->instance_table[i]); 1128 spin_lock_init(&log->instances_lock); 1129 1130 #ifdef CONFIG_PROC_FS 1131 proc = proc_create_net("nfnetlink_log", 0440, net->nf.proc_netfilter, 1132 &nful_seq_ops, sizeof(struct iter_state)); 1133 if (!proc) 1134 return -ENOMEM; 1135 1136 root_uid = make_kuid(net->user_ns, 0); 1137 root_gid = make_kgid(net->user_ns, 0); 1138 if (uid_valid(root_uid) && gid_valid(root_gid)) 1139 proc_set_user(proc, root_uid, root_gid); 1140 #endif 1141 return 0; 1142 } 1143 1144 static void __net_exit nfnl_log_net_exit(struct net *net) 1145 { 1146 struct nfnl_log_net *log = nfnl_log_pernet(net); 1147 unsigned int i; 1148 1149 #ifdef CONFIG_PROC_FS 1150 remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter); 1151 #endif 1152 nf_log_unset(net, &nfulnl_logger); 1153 for (i = 0; i < INSTANCE_BUCKETS; i++) 1154 WARN_ON_ONCE(!hlist_empty(&log->instance_table[i])); 1155 } 1156 1157 static struct pernet_operations nfnl_log_net_ops = { 1158 .init = nfnl_log_net_init, 1159 .exit = nfnl_log_net_exit, 1160 .id = &nfnl_log_net_id, 1161 .size = sizeof(struct nfnl_log_net), 1162 }; 1163 1164 static int __init nfnetlink_log_init(void) 1165 { 1166 int status; 1167 1168 status = register_pernet_subsys(&nfnl_log_net_ops); 1169 if (status < 0) { 1170 pr_err("failed to register pernet ops\n"); 1171 goto out; 1172 } 1173 1174 netlink_register_notifier(&nfulnl_rtnl_notifier); 1175 status = nfnetlink_subsys_register(&nfulnl_subsys); 1176 if (status < 0) { 1177 pr_err("failed to create netlink socket\n"); 1178 goto cleanup_netlink_notifier; 1179 } 1180 1181 status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger); 1182 if (status < 0) { 1183 pr_err("failed to register logger\n"); 1184 goto cleanup_subsys; 1185 } 1186 1187 return status; 1188 1189 cleanup_subsys: 1190 nfnetlink_subsys_unregister(&nfulnl_subsys); 1191 cleanup_netlink_notifier: 1192 netlink_unregister_notifier(&nfulnl_rtnl_notifier); 1193 unregister_pernet_subsys(&nfnl_log_net_ops); 1194 out: 1195 return status; 1196 } 1197 1198 static void __exit nfnetlink_log_fini(void) 1199 { 1200 nfnetlink_subsys_unregister(&nfulnl_subsys); 1201 netlink_unregister_notifier(&nfulnl_rtnl_notifier); 1202 unregister_pernet_subsys(&nfnl_log_net_ops); 1203 nf_log_unregister(&nfulnl_logger); 1204 } 1205 1206 MODULE_DESCRIPTION("netfilter userspace logging"); 1207 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); 1208 MODULE_LICENSE("GPL"); 1209 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG); 1210 MODULE_ALIAS_NF_LOGGER(AF_INET, 1); 1211 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1); 1212 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1); 1213 MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */ 1214 MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */ 1215 1216 module_init(nfnetlink_log_init); 1217 module_exit(nfnetlink_log_fini); 1218