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