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_obj(*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 spin_lock(&inst->lock); 232 if (inst->copy_mode == NFULNL_COPY_DISABLED) { 233 /* attempt to UNBIND a queue already pending 234 * destruction via netlink close event. Ignore. 235 */ 236 spin_unlock(&inst->lock); 237 return; 238 } 239 240 /* first pull it out of the global list */ 241 hlist_del_rcu(&inst->hlist); 242 243 /* lockless readers wont be able to use us */ 244 inst->copy_mode = NFULNL_COPY_DISABLED; 245 246 if (inst->skb) 247 __nfulnl_flush(inst); 248 spin_unlock(&inst->lock); 249 250 /* and finally put the refcount */ 251 instance_put(inst); 252 } 253 254 static inline void 255 instance_destroy(struct nfnl_log_net *log, 256 struct nfulnl_instance *inst) 257 { 258 spin_lock_bh(&log->instances_lock); 259 __instance_destroy(inst); 260 spin_unlock_bh(&log->instances_lock); 261 } 262 263 static int 264 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode, 265 unsigned int range) 266 { 267 int status = 0; 268 269 spin_lock_bh(&inst->lock); 270 271 switch (mode) { 272 case NFULNL_COPY_NONE: 273 case NFULNL_COPY_META: 274 inst->copy_mode = mode; 275 inst->copy_range = 0; 276 break; 277 278 case NFULNL_COPY_PACKET: 279 inst->copy_mode = mode; 280 if (range == 0) 281 range = NFULNL_COPY_RANGE_MAX; 282 inst->copy_range = min_t(unsigned int, 283 range, NFULNL_COPY_RANGE_MAX); 284 break; 285 286 default: 287 status = -EINVAL; 288 break; 289 } 290 291 spin_unlock_bh(&inst->lock); 292 293 return status; 294 } 295 296 static int 297 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz) 298 { 299 int status; 300 301 spin_lock_bh(&inst->lock); 302 if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT) 303 status = -ERANGE; 304 else if (nlbufsiz > 131072) 305 status = -ERANGE; 306 else { 307 inst->nlbufsiz = nlbufsiz; 308 status = 0; 309 } 310 spin_unlock_bh(&inst->lock); 311 312 return status; 313 } 314 315 static void 316 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout) 317 { 318 spin_lock_bh(&inst->lock); 319 inst->flushtimeout = timeout; 320 spin_unlock_bh(&inst->lock); 321 } 322 323 static void 324 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh) 325 { 326 spin_lock_bh(&inst->lock); 327 inst->qthreshold = qthresh; 328 spin_unlock_bh(&inst->lock); 329 } 330 331 static int 332 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags) 333 { 334 spin_lock_bh(&inst->lock); 335 inst->flags = flags; 336 spin_unlock_bh(&inst->lock); 337 338 return 0; 339 } 340 341 static struct sk_buff * 342 nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size, 343 unsigned int pkt_size) 344 { 345 struct sk_buff *skb; 346 unsigned int n; 347 348 /* alloc skb which should be big enough for a whole multipart 349 * message. WARNING: has to be <= 128k due to slab restrictions */ 350 351 n = max(inst_size, pkt_size); 352 skb = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN); 353 if (!skb) { 354 if (n > pkt_size) { 355 /* try to allocate only as much as we need for current 356 * packet */ 357 358 skb = alloc_skb(pkt_size, GFP_ATOMIC); 359 } 360 } 361 362 return skb; 363 } 364 365 static void 366 __nfulnl_send(struct nfulnl_instance *inst) 367 { 368 if (inst->qlen > 1) { 369 struct nlmsghdr *nlh = nfnl_msg_put(inst->skb, 0, 0, 370 NLMSG_DONE, 0, 371 AF_UNSPEC, NFNETLINK_V0, 372 htons(inst->group_num)); 373 if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n", 374 inst->skb->len, skb_tailroom(inst->skb))) { 375 kfree_skb(inst->skb); 376 goto out; 377 } 378 } 379 nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid); 380 out: 381 inst->qlen = 0; 382 inst->skb = NULL; 383 } 384 385 static void 386 __nfulnl_flush(struct nfulnl_instance *inst) 387 { 388 /* timer holds a reference */ 389 if (timer_delete(&inst->timer)) 390 instance_put(inst); 391 if (inst->skb) 392 __nfulnl_send(inst); 393 } 394 395 static void 396 nfulnl_timer(struct timer_list *t) 397 { 398 struct nfulnl_instance *inst = timer_container_of(inst, t, timer); 399 400 spin_lock_bh(&inst->lock); 401 if (inst->skb) 402 __nfulnl_send(inst); 403 spin_unlock_bh(&inst->lock); 404 instance_put(inst); 405 } 406 407 static u32 nfulnl_get_bridge_size(const struct sk_buff *skb) 408 { 409 u32 mac_len, size = 0; 410 411 if (!skb_mac_header_was_set(skb)) 412 return 0; 413 414 if (skb_vlan_tag_present(skb)) { 415 size += nla_total_size(0); /* nested */ 416 size += nla_total_size(sizeof(u16)); /* id */ 417 size += nla_total_size(sizeof(u16)); /* tag */ 418 } 419 420 mac_len = skb_mac_header_len(skb); 421 if (mac_len > 0) 422 size += nla_total_size(mac_len); 423 424 return size; 425 } 426 427 static int nfulnl_put_bridge(struct nfulnl_instance *inst, const struct sk_buff *skb) 428 { 429 u32 mac_len; 430 431 if (!skb_mac_header_was_set(skb)) 432 return 0; 433 434 if (skb_vlan_tag_present(skb)) { 435 struct nlattr *nest; 436 437 nest = nla_nest_start(inst->skb, NFULA_VLAN); 438 if (!nest) 439 goto nla_put_failure; 440 441 if (nla_put_be16(inst->skb, NFULA_VLAN_TCI, htons(skb->vlan_tci)) || 442 nla_put_be16(inst->skb, NFULA_VLAN_PROTO, skb->vlan_proto)) 443 goto nla_put_failure; 444 445 nla_nest_end(inst->skb, nest); 446 } 447 448 mac_len = skb_mac_header_len(skb); 449 if (mac_len > 0 && 450 nla_put(inst->skb, NFULA_L2HDR, mac_len, skb_mac_header(skb))) 451 goto nla_put_failure; 452 453 return 0; 454 455 nla_put_failure: 456 return -1; 457 } 458 459 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 460 static int nflog_put_master_ifindex(struct sk_buff *nlskb, int attr, 461 const struct net_device *dev) 462 { 463 const struct net_device *upper; 464 465 if (dev && !netif_is_bridge_port(dev)) 466 return 0; 467 468 upper = netdev_master_upper_dev_get_rcu((struct net_device *)dev); 469 if (upper && nla_put_be32(nlskb, attr, htonl(upper->ifindex))) 470 return -EMSGSIZE; 471 472 return 0; 473 } 474 #endif 475 476 /* This is an inline function, we don't really care about a long 477 * list of arguments */ 478 static inline int 479 __build_packet_message(struct nfnl_log_net *log, 480 struct nfulnl_instance *inst, 481 const struct sk_buff *skb, 482 unsigned int data_len, 483 u_int8_t pf, 484 unsigned int hooknum, 485 const struct net_device *indev, 486 const struct net_device *outdev, 487 const char *prefix, unsigned int plen, 488 const struct nfnl_ct_hook *nfnl_ct, 489 struct nf_conn *ct, enum ip_conntrack_info ctinfo) 490 { 491 struct nfulnl_msg_packet_hdr pmsg; 492 struct nlmsghdr *nlh; 493 sk_buff_data_t old_tail = inst->skb->tail; 494 struct sock *sk; 495 const unsigned char *hwhdrp; 496 497 nlh = nfnl_msg_put(inst->skb, 0, 0, 498 nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET), 499 0, pf, NFNETLINK_V0, htons(inst->group_num)); 500 if (!nlh) 501 return -1; 502 503 memset(&pmsg, 0, sizeof(pmsg)); 504 pmsg.hw_protocol = skb->protocol; 505 pmsg.hook = hooknum; 506 507 if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg)) 508 goto nla_put_failure; 509 510 if (prefix && 511 nla_put(inst->skb, NFULA_PREFIX, plen, prefix)) 512 goto nla_put_failure; 513 514 if (indev) { 515 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 516 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 517 htonl(indev->ifindex))) 518 goto nla_put_failure; 519 #else 520 if (pf == PF_BRIDGE) { 521 /* Case 1: outdev is physical input device, we need to 522 * look for bridge group (when called from 523 * netfilter_bridge) */ 524 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV, 525 htonl(indev->ifindex)) || 526 /* this is the bridge group "brX" */ 527 /* rcu_read_lock()ed by nf_hook_thresh or 528 * nf_log_packet. 529 */ 530 nflog_put_master_ifindex(inst->skb, NFULA_IFINDEX_INDEV, indev)) 531 goto nla_put_failure; 532 } else { 533 int physinif; 534 535 /* Case 2: indev is bridge group, we need to look for 536 * physical device (when called from ipv4) */ 537 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 538 htonl(indev->ifindex))) 539 goto nla_put_failure; 540 541 physinif = nf_bridge_get_physinif(skb); 542 if (physinif && 543 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV, 544 htonl(physinif))) 545 goto nla_put_failure; 546 } 547 #endif 548 } 549 550 if (outdev) { 551 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 552 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 553 htonl(outdev->ifindex))) 554 goto nla_put_failure; 555 #else 556 if (pf == PF_BRIDGE) { 557 /* Case 1: outdev is physical output device, we need to 558 * look for bridge group (when called from 559 * netfilter_bridge) */ 560 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV, 561 htonl(outdev->ifindex)) || 562 /* this is the bridge group "brX" */ 563 /* rcu_read_lock()ed by nf_hook_thresh or 564 * nf_log_packet. 565 */ 566 nflog_put_master_ifindex(inst->skb, NFULA_IFINDEX_OUTDEV, outdev)) 567 goto nla_put_failure; 568 } else { 569 struct net_device *physoutdev; 570 571 /* Case 2: indev is a bridge group, we need to look 572 * for physical device (when called from ipv4) */ 573 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 574 htonl(outdev->ifindex))) 575 goto nla_put_failure; 576 577 physoutdev = nf_bridge_get_physoutdev(skb); 578 if (physoutdev && 579 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV, 580 htonl(physoutdev->ifindex))) 581 goto nla_put_failure; 582 } 583 #endif 584 } 585 586 if (skb->mark && 587 nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark))) 588 goto nla_put_failure; 589 590 if (indev && skb->dev && 591 skb_mac_header_was_set(skb) && 592 skb_mac_header_len(skb) != 0) { 593 struct nfulnl_msg_packet_hw phw; 594 int len; 595 596 memset(&phw, 0, sizeof(phw)); 597 len = dev_parse_header(skb, phw.hw_addr); 598 if (len > 0) { 599 phw.hw_addrlen = htons(len); 600 if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw)) 601 goto nla_put_failure; 602 } 603 } 604 605 if (indev && skb_mac_header_was_set(skb)) { 606 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) || 607 nla_put_be16(inst->skb, NFULA_HWLEN, 608 htons(skb->dev->hard_header_len))) 609 goto nla_put_failure; 610 611 hwhdrp = skb_mac_header(skb); 612 613 if (skb->dev->type == ARPHRD_SIT) 614 hwhdrp -= ETH_HLEN; 615 616 if (hwhdrp >= skb->head && 617 nla_put(inst->skb, NFULA_HWHEADER, 618 skb->dev->hard_header_len, hwhdrp)) 619 goto nla_put_failure; 620 } 621 622 if (hooknum <= NF_INET_FORWARD) { 623 struct timespec64 kts = ktime_to_timespec64(skb_tstamp_cond(skb, true)); 624 struct nfulnl_msg_packet_timestamp ts; 625 ts.sec = cpu_to_be64(kts.tv_sec); 626 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC); 627 628 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts)) 629 goto nla_put_failure; 630 } 631 632 /* UID */ 633 sk = skb->sk; 634 if (sk && sk_fullsock(sk)) { 635 const struct socket *sock; 636 const struct file *file; 637 638 /* The sk pointer remains valid as long as the skb is. 639 * The sk_socket and file pointer may become NULL 640 * if the socket is closed. 641 * Both structures (including file->cred) are RCU freed 642 * which means they can be accessed within a RCU read section. 643 */ 644 sock = READ_ONCE(sk->sk_socket); 645 file = sock ? READ_ONCE(sock->file) : NULL; 646 if (file) { 647 const struct cred *cred = file->f_cred; 648 struct user_namespace *user_ns = inst->peer_user_ns; 649 __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid)); 650 __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid)); 651 if (nla_put_be32(inst->skb, NFULA_UID, uid) || 652 nla_put_be32(inst->skb, NFULA_GID, gid)) 653 goto nla_put_failure; 654 } 655 } 656 657 /* local sequence number */ 658 if ((inst->flags & NFULNL_CFG_F_SEQ) && 659 nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++))) 660 goto nla_put_failure; 661 662 /* global sequence number */ 663 if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) && 664 nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL, 665 htonl(atomic_inc_return(&log->global_seq)))) 666 goto nla_put_failure; 667 668 if (ct && nfnl_ct->build(inst->skb, ct, ctinfo, 669 NFULA_CT, NFULA_CT_INFO) < 0) 670 goto nla_put_failure; 671 672 if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) && 673 nfulnl_put_bridge(inst, skb) < 0) 674 goto nla_put_failure; 675 676 if (data_len) { 677 struct nlattr *nla; 678 679 nla = nla_reserve(inst->skb, NFULA_PAYLOAD, data_len); 680 if (!nla) 681 goto nla_put_failure; 682 683 if (skb_copy_bits(skb, 0, nla_data(nla), data_len)) 684 goto nla_put_failure; 685 } 686 687 nlh->nlmsg_len = inst->skb->tail - old_tail; 688 return 0; 689 690 nla_put_failure: 691 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n"); 692 return -1; 693 } 694 695 static const struct nf_loginfo default_loginfo = { 696 .type = NF_LOG_TYPE_ULOG, 697 .u = { 698 .ulog = { 699 .copy_len = 0xffff, 700 .group = 0, 701 .qthreshold = 1, 702 }, 703 }, 704 }; 705 706 static unsigned int nfulnl_get_copy_len(const struct nf_loginfo *li, 707 const struct sk_buff *skb, 708 unsigned int copy_len) 709 { 710 unsigned int len = skb->len; 711 712 if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) && 713 li->u.ulog.copy_len < copy_len) 714 copy_len = li->u.ulog.copy_len; 715 if (!skb_frags_readable(skb)) 716 len = skb_headlen(skb); 717 718 return min(len, copy_len); 719 } 720 721 /* log handler for internal netfilter logging api */ 722 static void 723 nfulnl_log_packet(struct net *net, 724 u_int8_t pf, 725 unsigned int hooknum, 726 const struct sk_buff *skb, 727 const struct net_device *in, 728 const struct net_device *out, 729 const struct nf_loginfo *li_user, 730 const char *prefix) 731 { 732 size_t size; 733 unsigned int data_len; 734 struct nfulnl_instance *inst; 735 const struct nf_loginfo *li; 736 unsigned int qthreshold; 737 unsigned int plen = 0; 738 struct nfnl_log_net *log = nfnl_log_pernet(net); 739 const struct nfnl_ct_hook *nfnl_ct = NULL; 740 enum ip_conntrack_info ctinfo = 0; 741 struct nf_conn *ct = NULL; 742 743 if (li_user && li_user->type == NF_LOG_TYPE_ULOG) 744 li = li_user; 745 else 746 li = &default_loginfo; 747 748 inst = instance_lookup_get_rcu(log, li->u.ulog.group); 749 if (!inst) 750 return; 751 752 if (prefix) 753 plen = strlen(prefix) + 1; 754 755 /* FIXME: do we want to make the size calculation conditional based on 756 * what is actually present? way more branches and checks, but more 757 * memory efficient... */ 758 size = nlmsg_total_size(sizeof(struct nfgenmsg)) 759 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr)) 760 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 761 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 762 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 763 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 764 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 765 #endif 766 + nla_total_size(sizeof(u_int32_t)) /* mark */ 767 + nla_total_size(sizeof(u_int32_t)) /* uid */ 768 + nla_total_size(sizeof(u_int32_t)) /* gid */ 769 + nla_total_size(plen) /* prefix */ 770 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw)) 771 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp)) 772 + nlmsg_total_size(sizeof(struct nfgenmsg)); /* NLMSG_DONE */ 773 774 if (in && skb_mac_header_was_set(skb)) { 775 size += nla_total_size(skb->dev->hard_header_len) 776 + nla_total_size(sizeof(u_int16_t)) /* hwtype */ 777 + nla_total_size(sizeof(u_int16_t)); /* hwlen */ 778 } 779 780 spin_lock_bh(&inst->lock); 781 782 if (inst->flags & NFULNL_CFG_F_SEQ) 783 size += nla_total_size(sizeof(u_int32_t)); 784 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) 785 size += nla_total_size(sizeof(u_int32_t)); 786 #if IS_ENABLED(CONFIG_NF_CONNTRACK) 787 if (inst->flags & NFULNL_CFG_F_CONNTRACK) { 788 nfnl_ct = rcu_dereference(nfnl_ct_hook); 789 if (nfnl_ct != NULL) { 790 ct = nf_ct_get(skb, &ctinfo); 791 if (ct != NULL) 792 size += nfnl_ct->build_size(ct); 793 } 794 } 795 #endif 796 if (pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) 797 size += nfulnl_get_bridge_size(skb); 798 799 qthreshold = inst->qthreshold; 800 /* per-rule qthreshold overrides per-instance */ 801 if (li->u.ulog.qthreshold) 802 if (qthreshold > li->u.ulog.qthreshold) 803 qthreshold = li->u.ulog.qthreshold; 804 805 806 switch (inst->copy_mode) { 807 case NFULNL_COPY_META: 808 case NFULNL_COPY_NONE: 809 data_len = 0; 810 break; 811 812 case NFULNL_COPY_PACKET: 813 data_len = nfulnl_get_copy_len(li, skb, inst->copy_range); 814 size += nla_total_size(data_len); 815 break; 816 817 case NFULNL_COPY_DISABLED: 818 default: 819 goto unlock_and_release; 820 } 821 822 if (inst->skb && size > skb_tailroom(inst->skb)) { 823 /* either the queue len is too high or we don't have 824 * enough room in the skb left. flush to userspace. */ 825 __nfulnl_flush(inst); 826 } 827 828 if (!inst->skb) { 829 inst->skb = nfulnl_alloc_skb(net, inst->peer_portid, 830 inst->nlbufsiz, size); 831 if (!inst->skb) 832 goto alloc_failure; 833 } 834 835 inst->qlen++; 836 837 __build_packet_message(log, inst, skb, data_len, pf, 838 hooknum, in, out, prefix, plen, 839 nfnl_ct, ct, ctinfo); 840 841 if (inst->qlen >= qthreshold) 842 __nfulnl_flush(inst); 843 /* timer_pending always called within inst->lock, so there 844 * is no chance of a race here */ 845 else if (!timer_pending(&inst->timer)) { 846 instance_get(inst); 847 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100); 848 add_timer(&inst->timer); 849 } 850 851 unlock_and_release: 852 spin_unlock_bh(&inst->lock); 853 instance_put(inst); 854 return; 855 856 alloc_failure: 857 /* FIXME: statistics */ 858 goto unlock_and_release; 859 } 860 861 static int 862 nfulnl_rcv_nl_event(struct notifier_block *this, 863 unsigned long event, void *ptr) 864 { 865 struct netlink_notify *n = ptr; 866 struct nfnl_log_net *log = nfnl_log_pernet(n->net); 867 868 if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) { 869 int i; 870 871 /* destroy all instances for this portid */ 872 spin_lock_bh(&log->instances_lock); 873 for (i = 0; i < INSTANCE_BUCKETS; i++) { 874 struct hlist_node *t2; 875 struct nfulnl_instance *inst; 876 struct hlist_head *head = &log->instance_table[i]; 877 878 hlist_for_each_entry_safe(inst, t2, head, hlist) { 879 if (n->portid == inst->peer_portid) 880 __instance_destroy(inst); 881 } 882 } 883 spin_unlock_bh(&log->instances_lock); 884 } 885 return NOTIFY_DONE; 886 } 887 888 static struct notifier_block nfulnl_rtnl_notifier = { 889 .notifier_call = nfulnl_rcv_nl_event, 890 }; 891 892 static int nfulnl_recv_unsupp(struct sk_buff *skb, const struct nfnl_info *info, 893 const struct nlattr * const nfula[]) 894 { 895 return -ENOTSUPP; 896 } 897 898 static struct nf_logger nfulnl_logger __read_mostly = { 899 .name = "nfnetlink_log", 900 .type = NF_LOG_TYPE_ULOG, 901 .logfn = nfulnl_log_packet, 902 .me = THIS_MODULE, 903 }; 904 905 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = { 906 [NFULA_CFG_CMD] = { .len = sizeof(struct nfulnl_msg_config_cmd) }, 907 [NFULA_CFG_MODE] = { .len = sizeof(struct nfulnl_msg_config_mode) }, 908 [NFULA_CFG_TIMEOUT] = { .type = NLA_U32 }, 909 [NFULA_CFG_QTHRESH] = { .type = NLA_U32 }, 910 [NFULA_CFG_NLBUFSIZ] = { .type = NLA_U32 }, 911 [NFULA_CFG_FLAGS] = NLA_POLICY_MASK(NLA_BE16, NFULNL_CFG_F_SEQ | 912 NFULNL_CFG_F_SEQ_GLOBAL | 913 NFULNL_CFG_F_CONNTRACK), 914 }; 915 916 static int nfulnl_recv_config(struct sk_buff *skb, const struct nfnl_info *info, 917 const struct nlattr * const nfula[]) 918 { 919 struct nfnl_log_net *log = nfnl_log_pernet(info->net); 920 u_int16_t group_num = ntohs(info->nfmsg->res_id); 921 struct nfulnl_msg_config_cmd *cmd = NULL; 922 struct nfulnl_instance *inst; 923 u16 flags = 0; 924 int ret = 0; 925 926 if (nfula[NFULA_CFG_CMD]) { 927 u_int8_t pf = info->nfmsg->nfgen_family; 928 cmd = nla_data(nfula[NFULA_CFG_CMD]); 929 930 /* Commands without queue context */ 931 switch (cmd->command) { 932 case NFULNL_CFG_CMD_PF_BIND: 933 return nf_log_bind_pf(info->net, pf, &nfulnl_logger); 934 case NFULNL_CFG_CMD_PF_UNBIND: 935 nf_log_unbind_pf(info->net, pf); 936 return 0; 937 } 938 } 939 940 inst = instance_lookup_get(log, group_num); 941 if (inst && inst->peer_portid != NETLINK_CB(skb).portid) { 942 ret = -EPERM; 943 goto out_put; 944 } 945 946 /* Check if we support these flags in first place, dependencies should 947 * be there too not to break atomicity. 948 */ 949 if (nfula[NFULA_CFG_FLAGS]) { 950 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS])); 951 952 if ((flags & NFULNL_CFG_F_CONNTRACK) && 953 !rcu_access_pointer(nfnl_ct_hook)) { 954 #ifdef CONFIG_MODULES 955 nfnl_unlock(NFNL_SUBSYS_ULOG); 956 request_module("ip_conntrack_netlink"); 957 nfnl_lock(NFNL_SUBSYS_ULOG); 958 if (rcu_access_pointer(nfnl_ct_hook)) { 959 ret = -EAGAIN; 960 goto out_put; 961 } 962 #endif 963 ret = -EOPNOTSUPP; 964 goto out_put; 965 } 966 } 967 968 if (cmd != NULL) { 969 switch (cmd->command) { 970 case NFULNL_CFG_CMD_BIND: 971 if (inst) { 972 ret = -EBUSY; 973 goto out_put; 974 } 975 976 inst = instance_create(info->net, group_num, 977 NETLINK_CB(skb).portid, 978 sk_user_ns(NETLINK_CB(skb).sk)); 979 if (IS_ERR(inst)) { 980 ret = PTR_ERR(inst); 981 goto out; 982 } 983 break; 984 case NFULNL_CFG_CMD_UNBIND: 985 if (!inst) { 986 ret = -ENODEV; 987 goto out; 988 } 989 990 instance_destroy(log, inst); 991 goto out_put; 992 default: 993 ret = -ENOTSUPP; 994 goto out_put; 995 } 996 } else if (!inst) { 997 ret = -ENODEV; 998 goto out; 999 } 1000 1001 if (nfula[NFULA_CFG_MODE]) { 1002 struct nfulnl_msg_config_mode *params = 1003 nla_data(nfula[NFULA_CFG_MODE]); 1004 1005 nfulnl_set_mode(inst, params->copy_mode, 1006 ntohl(params->copy_range)); 1007 } 1008 1009 if (nfula[NFULA_CFG_TIMEOUT]) { 1010 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]); 1011 1012 nfulnl_set_timeout(inst, ntohl(timeout)); 1013 } 1014 1015 if (nfula[NFULA_CFG_NLBUFSIZ]) { 1016 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]); 1017 1018 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz)); 1019 } 1020 1021 if (nfula[NFULA_CFG_QTHRESH]) { 1022 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]); 1023 1024 nfulnl_set_qthresh(inst, ntohl(qthresh)); 1025 } 1026 1027 if (nfula[NFULA_CFG_FLAGS]) 1028 nfulnl_set_flags(inst, flags); 1029 1030 out_put: 1031 instance_put(inst); 1032 out: 1033 return ret; 1034 } 1035 1036 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = { 1037 [NFULNL_MSG_PACKET] = { 1038 .call = nfulnl_recv_unsupp, 1039 .type = NFNL_CB_MUTEX, 1040 .attr_count = NFULA_MAX, 1041 }, 1042 [NFULNL_MSG_CONFIG] = { 1043 .call = nfulnl_recv_config, 1044 .type = NFNL_CB_MUTEX, 1045 .attr_count = NFULA_CFG_MAX, 1046 .policy = nfula_cfg_policy 1047 }, 1048 }; 1049 1050 static const struct nfnetlink_subsystem nfulnl_subsys = { 1051 .name = "log", 1052 .subsys_id = NFNL_SUBSYS_ULOG, 1053 .cb_count = NFULNL_MSG_MAX, 1054 .cb = nfulnl_cb, 1055 }; 1056 1057 #ifdef CONFIG_PROC_FS 1058 struct iter_state { 1059 struct seq_net_private p; 1060 unsigned int bucket; 1061 }; 1062 1063 static struct hlist_node *get_first(struct net *net, struct iter_state *st) 1064 { 1065 struct nfnl_log_net *log; 1066 if (!st) 1067 return NULL; 1068 1069 log = nfnl_log_pernet(net); 1070 1071 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) { 1072 struct hlist_head *head = &log->instance_table[st->bucket]; 1073 1074 if (!hlist_empty(head)) 1075 return rcu_dereference(hlist_first_rcu(head)); 1076 } 1077 return NULL; 1078 } 1079 1080 static struct hlist_node *get_next(struct net *net, struct iter_state *st, 1081 struct hlist_node *h) 1082 { 1083 h = rcu_dereference(hlist_next_rcu(h)); 1084 while (!h) { 1085 struct nfnl_log_net *log; 1086 struct hlist_head *head; 1087 1088 if (++st->bucket >= INSTANCE_BUCKETS) 1089 return NULL; 1090 1091 log = nfnl_log_pernet(net); 1092 head = &log->instance_table[st->bucket]; 1093 h = rcu_dereference(hlist_first_rcu(head)); 1094 } 1095 return h; 1096 } 1097 1098 static struct hlist_node *get_idx(struct net *net, struct iter_state *st, 1099 loff_t pos) 1100 { 1101 struct hlist_node *head; 1102 head = get_first(net, st); 1103 1104 if (head) 1105 while (pos && (head = get_next(net, st, head))) 1106 pos--; 1107 return pos ? NULL : head; 1108 } 1109 1110 static void *seq_start(struct seq_file *s, loff_t *pos) 1111 __acquires(rcu) 1112 { 1113 rcu_read_lock(); 1114 return get_idx(seq_file_net(s), s->private, *pos); 1115 } 1116 1117 static void *seq_next(struct seq_file *s, void *v, loff_t *pos) 1118 { 1119 (*pos)++; 1120 return get_next(seq_file_net(s), s->private, v); 1121 } 1122 1123 static void seq_stop(struct seq_file *s, void *v) 1124 __releases(rcu) 1125 { 1126 rcu_read_unlock(); 1127 } 1128 1129 static int seq_show(struct seq_file *s, void *v) 1130 { 1131 const struct nfulnl_instance *inst = v; 1132 1133 seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n", 1134 inst->group_num, 1135 inst->peer_portid, inst->qlen, 1136 inst->copy_mode, inst->copy_range, 1137 inst->flushtimeout, refcount_read(&inst->use)); 1138 1139 return 0; 1140 } 1141 1142 static const struct seq_operations nful_seq_ops = { 1143 .start = seq_start, 1144 .next = seq_next, 1145 .stop = seq_stop, 1146 .show = seq_show, 1147 }; 1148 #endif /* PROC_FS */ 1149 1150 static int __net_init nfnl_log_net_init(struct net *net) 1151 { 1152 unsigned int i; 1153 struct nfnl_log_net *log = nfnl_log_pernet(net); 1154 #ifdef CONFIG_PROC_FS 1155 struct proc_dir_entry *proc; 1156 kuid_t root_uid; 1157 kgid_t root_gid; 1158 #endif 1159 1160 for (i = 0; i < INSTANCE_BUCKETS; i++) 1161 INIT_HLIST_HEAD(&log->instance_table[i]); 1162 spin_lock_init(&log->instances_lock); 1163 1164 #ifdef CONFIG_PROC_FS 1165 proc = proc_create_net("nfnetlink_log", 0440, net->nf.proc_netfilter, 1166 &nful_seq_ops, sizeof(struct iter_state)); 1167 if (!proc) 1168 return -ENOMEM; 1169 1170 root_uid = make_kuid(net->user_ns, 0); 1171 root_gid = make_kgid(net->user_ns, 0); 1172 if (uid_valid(root_uid) && gid_valid(root_gid)) 1173 proc_set_user(proc, root_uid, root_gid); 1174 #endif 1175 return 0; 1176 } 1177 1178 static void __net_exit nfnl_log_net_pre_exit(struct net *net) 1179 { 1180 #ifdef CONFIG_PROC_FS 1181 remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter); 1182 #endif 1183 nf_log_unset(net, &nfulnl_logger); 1184 } 1185 1186 static void __net_exit nfnl_log_net_exit(struct net *net) 1187 { 1188 struct nfnl_log_net *log = nfnl_log_pernet(net); 1189 unsigned int i; 1190 1191 for (i = 0; i < INSTANCE_BUCKETS; i++) 1192 WARN_ON_ONCE(!hlist_empty(&log->instance_table[i])); 1193 } 1194 1195 static struct pernet_operations nfnl_log_net_ops = { 1196 .init = nfnl_log_net_init, 1197 .pre_exit = nfnl_log_net_pre_exit, 1198 .exit = nfnl_log_net_exit, 1199 .id = &nfnl_log_net_id, 1200 .size = sizeof(struct nfnl_log_net), 1201 }; 1202 1203 static int __init nfnetlink_log_init(void) 1204 { 1205 int status; 1206 1207 status = register_pernet_subsys(&nfnl_log_net_ops); 1208 if (status < 0) { 1209 pr_err("failed to register pernet ops\n"); 1210 goto out; 1211 } 1212 1213 netlink_register_notifier(&nfulnl_rtnl_notifier); 1214 status = nfnetlink_subsys_register(&nfulnl_subsys); 1215 if (status < 0) { 1216 pr_err("failed to create netlink socket\n"); 1217 goto cleanup_netlink_notifier; 1218 } 1219 1220 status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger); 1221 if (status < 0) { 1222 pr_err("failed to register logger\n"); 1223 goto cleanup_subsys; 1224 } 1225 1226 return status; 1227 1228 cleanup_subsys: 1229 nfnetlink_subsys_unregister(&nfulnl_subsys); 1230 cleanup_netlink_notifier: 1231 netlink_unregister_notifier(&nfulnl_rtnl_notifier); 1232 unregister_pernet_subsys(&nfnl_log_net_ops); 1233 out: 1234 return status; 1235 } 1236 1237 static void __exit nfnetlink_log_fini(void) 1238 { 1239 nfnetlink_subsys_unregister(&nfulnl_subsys); 1240 netlink_unregister_notifier(&nfulnl_rtnl_notifier); 1241 nf_log_unregister(&nfulnl_logger); 1242 unregister_pernet_subsys(&nfnl_log_net_ops); 1243 } 1244 1245 MODULE_DESCRIPTION("netfilter userspace logging"); 1246 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); 1247 MODULE_LICENSE("GPL"); 1248 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG); 1249 MODULE_ALIAS_NF_LOGGER(AF_INET, 1); 1250 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1); 1251 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1); 1252 MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */ 1253 MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */ 1254 1255 module_init(nfnetlink_log_init); 1256 module_exit(nfnetlink_log_fini); 1257