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