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 MSG_DONTWAIT); 361 out: 362 inst->qlen = 0; 363 inst->skb = NULL; 364 } 365 366 static void 367 __nfulnl_flush(struct nfulnl_instance *inst) 368 { 369 /* timer holds a reference */ 370 if (del_timer(&inst->timer)) 371 instance_put(inst); 372 if (inst->skb) 373 __nfulnl_send(inst); 374 } 375 376 static void 377 nfulnl_timer(struct timer_list *t) 378 { 379 struct nfulnl_instance *inst = from_timer(inst, t, timer); 380 381 spin_lock_bh(&inst->lock); 382 if (inst->skb) 383 __nfulnl_send(inst); 384 spin_unlock_bh(&inst->lock); 385 instance_put(inst); 386 } 387 388 static u32 nfulnl_get_bridge_size(const struct sk_buff *skb) 389 { 390 u32 size = 0; 391 392 if (!skb_mac_header_was_set(skb)) 393 return 0; 394 395 if (skb_vlan_tag_present(skb)) { 396 size += nla_total_size(0); /* nested */ 397 size += nla_total_size(sizeof(u16)); /* id */ 398 size += nla_total_size(sizeof(u16)); /* tag */ 399 } 400 401 if (skb->network_header > skb->mac_header) 402 size += nla_total_size(skb->network_header - skb->mac_header); 403 404 return size; 405 } 406 407 static int nfulnl_put_bridge(struct nfulnl_instance *inst, const struct sk_buff *skb) 408 { 409 if (!skb_mac_header_was_set(skb)) 410 return 0; 411 412 if (skb_vlan_tag_present(skb)) { 413 struct nlattr *nest; 414 415 nest = nla_nest_start(inst->skb, NFULA_VLAN); 416 if (!nest) 417 goto nla_put_failure; 418 419 if (nla_put_be16(inst->skb, NFULA_VLAN_TCI, htons(skb->vlan_tci)) || 420 nla_put_be16(inst->skb, NFULA_VLAN_PROTO, skb->vlan_proto)) 421 goto nla_put_failure; 422 423 nla_nest_end(inst->skb, nest); 424 } 425 426 if (skb->mac_header < skb->network_header) { 427 int len = (int)(skb->network_header - skb->mac_header); 428 429 if (nla_put(inst->skb, NFULA_L2HDR, len, skb_mac_header(skb))) 430 goto nla_put_failure; 431 } 432 433 return 0; 434 435 nla_put_failure: 436 return -1; 437 } 438 439 /* This is an inline function, we don't really care about a long 440 * list of arguments */ 441 static inline int 442 __build_packet_message(struct nfnl_log_net *log, 443 struct nfulnl_instance *inst, 444 const struct sk_buff *skb, 445 unsigned int data_len, 446 u_int8_t pf, 447 unsigned int hooknum, 448 const struct net_device *indev, 449 const struct net_device *outdev, 450 const char *prefix, unsigned int plen, 451 const struct nfnl_ct_hook *nfnl_ct, 452 struct nf_conn *ct, enum ip_conntrack_info ctinfo) 453 { 454 struct nfulnl_msg_packet_hdr pmsg; 455 struct nlmsghdr *nlh; 456 struct nfgenmsg *nfmsg; 457 sk_buff_data_t old_tail = inst->skb->tail; 458 struct sock *sk; 459 const unsigned char *hwhdrp; 460 461 nlh = nlmsg_put(inst->skb, 0, 0, 462 nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET), 463 sizeof(struct nfgenmsg), 0); 464 if (!nlh) 465 return -1; 466 nfmsg = nlmsg_data(nlh); 467 nfmsg->nfgen_family = pf; 468 nfmsg->version = NFNETLINK_V0; 469 nfmsg->res_id = htons(inst->group_num); 470 471 memset(&pmsg, 0, sizeof(pmsg)); 472 pmsg.hw_protocol = skb->protocol; 473 pmsg.hook = hooknum; 474 475 if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg)) 476 goto nla_put_failure; 477 478 if (prefix && 479 nla_put(inst->skb, NFULA_PREFIX, plen, prefix)) 480 goto nla_put_failure; 481 482 if (indev) { 483 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 484 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 485 htonl(indev->ifindex))) 486 goto nla_put_failure; 487 #else 488 if (pf == PF_BRIDGE) { 489 /* Case 1: outdev is physical input device, we need to 490 * look for bridge group (when called from 491 * netfilter_bridge) */ 492 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV, 493 htonl(indev->ifindex)) || 494 /* this is the bridge group "brX" */ 495 /* rcu_read_lock()ed by nf_hook_thresh or 496 * nf_log_packet. 497 */ 498 nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 499 htonl(br_port_get_rcu(indev)->br->dev->ifindex))) 500 goto nla_put_failure; 501 } else { 502 struct net_device *physindev; 503 504 /* Case 2: indev is bridge group, we need to look for 505 * physical device (when called from ipv4) */ 506 if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV, 507 htonl(indev->ifindex))) 508 goto nla_put_failure; 509 510 physindev = nf_bridge_get_physindev(skb); 511 if (physindev && 512 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV, 513 htonl(physindev->ifindex))) 514 goto nla_put_failure; 515 } 516 #endif 517 } 518 519 if (outdev) { 520 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 521 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 522 htonl(outdev->ifindex))) 523 goto nla_put_failure; 524 #else 525 if (pf == PF_BRIDGE) { 526 /* Case 1: outdev is physical output device, we need to 527 * look for bridge group (when called from 528 * netfilter_bridge) */ 529 if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV, 530 htonl(outdev->ifindex)) || 531 /* this is the bridge group "brX" */ 532 /* rcu_read_lock()ed by nf_hook_thresh or 533 * nf_log_packet. 534 */ 535 nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 536 htonl(br_port_get_rcu(outdev)->br->dev->ifindex))) 537 goto nla_put_failure; 538 } else { 539 struct net_device *physoutdev; 540 541 /* Case 2: indev is a bridge group, we need to look 542 * for physical device (when called from ipv4) */ 543 if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV, 544 htonl(outdev->ifindex))) 545 goto nla_put_failure; 546 547 physoutdev = nf_bridge_get_physoutdev(skb); 548 if (physoutdev && 549 nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV, 550 htonl(physoutdev->ifindex))) 551 goto nla_put_failure; 552 } 553 #endif 554 } 555 556 if (skb->mark && 557 nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark))) 558 goto nla_put_failure; 559 560 if (indev && skb->dev && 561 skb->mac_header != skb->network_header) { 562 struct nfulnl_msg_packet_hw phw; 563 int len; 564 565 memset(&phw, 0, sizeof(phw)); 566 len = dev_parse_header(skb, phw.hw_addr); 567 if (len > 0) { 568 phw.hw_addrlen = htons(len); 569 if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw)) 570 goto nla_put_failure; 571 } 572 } 573 574 if (indev && skb_mac_header_was_set(skb)) { 575 if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) || 576 nla_put_be16(inst->skb, NFULA_HWLEN, 577 htons(skb->dev->hard_header_len))) 578 goto nla_put_failure; 579 580 hwhdrp = skb_mac_header(skb); 581 582 if (skb->dev->type == ARPHRD_SIT) 583 hwhdrp -= ETH_HLEN; 584 585 if (hwhdrp >= skb->head && 586 nla_put(inst->skb, NFULA_HWHEADER, 587 skb->dev->hard_header_len, hwhdrp)) 588 goto nla_put_failure; 589 } 590 591 if (hooknum <= NF_INET_FORWARD && skb->tstamp) { 592 struct nfulnl_msg_packet_timestamp ts; 593 struct timespec64 kts = ktime_to_timespec64(skb->tstamp); 594 ts.sec = cpu_to_be64(kts.tv_sec); 595 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC); 596 597 if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts)) 598 goto nla_put_failure; 599 } 600 601 /* UID */ 602 sk = skb->sk; 603 if (sk && sk_fullsock(sk)) { 604 read_lock_bh(&sk->sk_callback_lock); 605 if (sk->sk_socket && sk->sk_socket->file) { 606 struct file *file = sk->sk_socket->file; 607 const struct cred *cred = file->f_cred; 608 struct user_namespace *user_ns = inst->peer_user_ns; 609 __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid)); 610 __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid)); 611 read_unlock_bh(&sk->sk_callback_lock); 612 if (nla_put_be32(inst->skb, NFULA_UID, uid) || 613 nla_put_be32(inst->skb, NFULA_GID, gid)) 614 goto nla_put_failure; 615 } else 616 read_unlock_bh(&sk->sk_callback_lock); 617 } 618 619 /* local sequence number */ 620 if ((inst->flags & NFULNL_CFG_F_SEQ) && 621 nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++))) 622 goto nla_put_failure; 623 624 /* global sequence number */ 625 if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) && 626 nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL, 627 htonl(atomic_inc_return(&log->global_seq)))) 628 goto nla_put_failure; 629 630 if (ct && nfnl_ct->build(inst->skb, ct, ctinfo, 631 NFULA_CT, NFULA_CT_INFO) < 0) 632 goto nla_put_failure; 633 634 if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) && 635 nfulnl_put_bridge(inst, skb) < 0) 636 goto nla_put_failure; 637 638 if (data_len) { 639 struct nlattr *nla; 640 int size = nla_attr_size(data_len); 641 642 if (skb_tailroom(inst->skb) < nla_total_size(data_len)) 643 goto nla_put_failure; 644 645 nla = skb_put(inst->skb, nla_total_size(data_len)); 646 nla->nla_type = NFULA_PAYLOAD; 647 nla->nla_len = size; 648 649 if (skb_copy_bits(skb, 0, nla_data(nla), data_len)) 650 BUG(); 651 } 652 653 nlh->nlmsg_len = inst->skb->tail - old_tail; 654 return 0; 655 656 nla_put_failure: 657 PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n"); 658 return -1; 659 } 660 661 static const struct nf_loginfo default_loginfo = { 662 .type = NF_LOG_TYPE_ULOG, 663 .u = { 664 .ulog = { 665 .copy_len = 0xffff, 666 .group = 0, 667 .qthreshold = 1, 668 }, 669 }, 670 }; 671 672 /* log handler for internal netfilter logging api */ 673 static void 674 nfulnl_log_packet(struct net *net, 675 u_int8_t pf, 676 unsigned int hooknum, 677 const struct sk_buff *skb, 678 const struct net_device *in, 679 const struct net_device *out, 680 const struct nf_loginfo *li_user, 681 const char *prefix) 682 { 683 size_t size; 684 unsigned int data_len; 685 struct nfulnl_instance *inst; 686 const struct nf_loginfo *li; 687 unsigned int qthreshold; 688 unsigned int plen = 0; 689 struct nfnl_log_net *log = nfnl_log_pernet(net); 690 const struct nfnl_ct_hook *nfnl_ct = NULL; 691 struct nf_conn *ct = NULL; 692 enum ip_conntrack_info ctinfo; 693 694 if (li_user && li_user->type == NF_LOG_TYPE_ULOG) 695 li = li_user; 696 else 697 li = &default_loginfo; 698 699 inst = instance_lookup_get(log, li->u.ulog.group); 700 if (!inst) 701 return; 702 703 if (prefix) 704 plen = strlen(prefix) + 1; 705 706 /* FIXME: do we want to make the size calculation conditional based on 707 * what is actually present? way more branches and checks, but more 708 * memory efficient... */ 709 size = nlmsg_total_size(sizeof(struct nfgenmsg)) 710 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr)) 711 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 712 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 713 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) 714 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 715 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ 716 #endif 717 + nla_total_size(sizeof(u_int32_t)) /* mark */ 718 + nla_total_size(sizeof(u_int32_t)) /* uid */ 719 + nla_total_size(sizeof(u_int32_t)) /* gid */ 720 + nla_total_size(plen) /* prefix */ 721 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw)) 722 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp)) 723 + nla_total_size(sizeof(struct nfgenmsg)); /* NLMSG_DONE */ 724 725 if (in && skb_mac_header_was_set(skb)) { 726 size += nla_total_size(skb->dev->hard_header_len) 727 + nla_total_size(sizeof(u_int16_t)) /* hwtype */ 728 + nla_total_size(sizeof(u_int16_t)); /* hwlen */ 729 } 730 731 spin_lock_bh(&inst->lock); 732 733 if (inst->flags & NFULNL_CFG_F_SEQ) 734 size += nla_total_size(sizeof(u_int32_t)); 735 if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) 736 size += nla_total_size(sizeof(u_int32_t)); 737 if (inst->flags & NFULNL_CFG_F_CONNTRACK) { 738 nfnl_ct = rcu_dereference(nfnl_ct_hook); 739 if (nfnl_ct != NULL) { 740 ct = nfnl_ct->get_ct(skb, &ctinfo); 741 if (ct != NULL) 742 size += nfnl_ct->build_size(ct); 743 } 744 } 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 net *net, struct sock *ctnl, 849 struct sk_buff *skb, const struct nlmsghdr *nlh, 850 const struct nlattr * const nfqa[], 851 struct netlink_ext_ack *extack) 852 { 853 return -ENOTSUPP; 854 } 855 856 static struct nf_logger nfulnl_logger __read_mostly = { 857 .name = "nfnetlink_log", 858 .type = NF_LOG_TYPE_ULOG, 859 .logfn = nfulnl_log_packet, 860 .me = THIS_MODULE, 861 }; 862 863 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = { 864 [NFULA_CFG_CMD] = { .len = sizeof(struct nfulnl_msg_config_cmd) }, 865 [NFULA_CFG_MODE] = { .len = sizeof(struct nfulnl_msg_config_mode) }, 866 [NFULA_CFG_TIMEOUT] = { .type = NLA_U32 }, 867 [NFULA_CFG_QTHRESH] = { .type = NLA_U32 }, 868 [NFULA_CFG_NLBUFSIZ] = { .type = NLA_U32 }, 869 [NFULA_CFG_FLAGS] = { .type = NLA_U16 }, 870 }; 871 872 static int nfulnl_recv_config(struct net *net, struct sock *ctnl, 873 struct sk_buff *skb, const struct nlmsghdr *nlh, 874 const struct nlattr * const nfula[], 875 struct netlink_ext_ack *extack) 876 { 877 struct nfgenmsg *nfmsg = nlmsg_data(nlh); 878 u_int16_t group_num = ntohs(nfmsg->res_id); 879 struct nfulnl_instance *inst; 880 struct nfulnl_msg_config_cmd *cmd = NULL; 881 struct nfnl_log_net *log = nfnl_log_pernet(net); 882 int ret = 0; 883 u16 flags = 0; 884 885 if (nfula[NFULA_CFG_CMD]) { 886 u_int8_t pf = nfmsg->nfgen_family; 887 cmd = nla_data(nfula[NFULA_CFG_CMD]); 888 889 /* Commands without queue context */ 890 switch (cmd->command) { 891 case NFULNL_CFG_CMD_PF_BIND: 892 return nf_log_bind_pf(net, pf, &nfulnl_logger); 893 case NFULNL_CFG_CMD_PF_UNBIND: 894 nf_log_unbind_pf(net, pf); 895 return 0; 896 } 897 } 898 899 inst = instance_lookup_get(log, group_num); 900 if (inst && inst->peer_portid != NETLINK_CB(skb).portid) { 901 ret = -EPERM; 902 goto out_put; 903 } 904 905 /* Check if we support these flags in first place, dependencies should 906 * be there too not to break atomicity. 907 */ 908 if (nfula[NFULA_CFG_FLAGS]) { 909 flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS])); 910 911 if ((flags & NFULNL_CFG_F_CONNTRACK) && 912 !rcu_access_pointer(nfnl_ct_hook)) { 913 #ifdef CONFIG_MODULES 914 nfnl_unlock(NFNL_SUBSYS_ULOG); 915 request_module("ip_conntrack_netlink"); 916 nfnl_lock(NFNL_SUBSYS_ULOG); 917 if (rcu_access_pointer(nfnl_ct_hook)) { 918 ret = -EAGAIN; 919 goto out_put; 920 } 921 #endif 922 ret = -EOPNOTSUPP; 923 goto out_put; 924 } 925 } 926 927 if (cmd != NULL) { 928 switch (cmd->command) { 929 case NFULNL_CFG_CMD_BIND: 930 if (inst) { 931 ret = -EBUSY; 932 goto out_put; 933 } 934 935 inst = instance_create(net, group_num, 936 NETLINK_CB(skb).portid, 937 sk_user_ns(NETLINK_CB(skb).sk)); 938 if (IS_ERR(inst)) { 939 ret = PTR_ERR(inst); 940 goto out; 941 } 942 break; 943 case NFULNL_CFG_CMD_UNBIND: 944 if (!inst) { 945 ret = -ENODEV; 946 goto out; 947 } 948 949 instance_destroy(log, inst); 950 goto out_put; 951 default: 952 ret = -ENOTSUPP; 953 goto out_put; 954 } 955 } else if (!inst) { 956 ret = -ENODEV; 957 goto out; 958 } 959 960 if (nfula[NFULA_CFG_MODE]) { 961 struct nfulnl_msg_config_mode *params = 962 nla_data(nfula[NFULA_CFG_MODE]); 963 964 nfulnl_set_mode(inst, params->copy_mode, 965 ntohl(params->copy_range)); 966 } 967 968 if (nfula[NFULA_CFG_TIMEOUT]) { 969 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]); 970 971 nfulnl_set_timeout(inst, ntohl(timeout)); 972 } 973 974 if (nfula[NFULA_CFG_NLBUFSIZ]) { 975 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]); 976 977 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz)); 978 } 979 980 if (nfula[NFULA_CFG_QTHRESH]) { 981 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]); 982 983 nfulnl_set_qthresh(inst, ntohl(qthresh)); 984 } 985 986 if (nfula[NFULA_CFG_FLAGS]) 987 nfulnl_set_flags(inst, flags); 988 989 out_put: 990 instance_put(inst); 991 out: 992 return ret; 993 } 994 995 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = { 996 [NFULNL_MSG_PACKET] = { .call = nfulnl_recv_unsupp, 997 .attr_count = NFULA_MAX, }, 998 [NFULNL_MSG_CONFIG] = { .call = nfulnl_recv_config, 999 .attr_count = NFULA_CFG_MAX, 1000 .policy = nfula_cfg_policy }, 1001 }; 1002 1003 static const struct nfnetlink_subsystem nfulnl_subsys = { 1004 .name = "log", 1005 .subsys_id = NFNL_SUBSYS_ULOG, 1006 .cb_count = NFULNL_MSG_MAX, 1007 .cb = nfulnl_cb, 1008 }; 1009 1010 #ifdef CONFIG_PROC_FS 1011 struct iter_state { 1012 struct seq_net_private p; 1013 unsigned int bucket; 1014 }; 1015 1016 static struct hlist_node *get_first(struct net *net, struct iter_state *st) 1017 { 1018 struct nfnl_log_net *log; 1019 if (!st) 1020 return NULL; 1021 1022 log = nfnl_log_pernet(net); 1023 1024 for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) { 1025 struct hlist_head *head = &log->instance_table[st->bucket]; 1026 1027 if (!hlist_empty(head)) 1028 return rcu_dereference_bh(hlist_first_rcu(head)); 1029 } 1030 return NULL; 1031 } 1032 1033 static struct hlist_node *get_next(struct net *net, struct iter_state *st, 1034 struct hlist_node *h) 1035 { 1036 h = rcu_dereference_bh(hlist_next_rcu(h)); 1037 while (!h) { 1038 struct nfnl_log_net *log; 1039 struct hlist_head *head; 1040 1041 if (++st->bucket >= INSTANCE_BUCKETS) 1042 return NULL; 1043 1044 log = nfnl_log_pernet(net); 1045 head = &log->instance_table[st->bucket]; 1046 h = rcu_dereference_bh(hlist_first_rcu(head)); 1047 } 1048 return h; 1049 } 1050 1051 static struct hlist_node *get_idx(struct net *net, struct iter_state *st, 1052 loff_t pos) 1053 { 1054 struct hlist_node *head; 1055 head = get_first(net, st); 1056 1057 if (head) 1058 while (pos && (head = get_next(net, st, head))) 1059 pos--; 1060 return pos ? NULL : head; 1061 } 1062 1063 static void *seq_start(struct seq_file *s, loff_t *pos) 1064 __acquires(rcu_bh) 1065 { 1066 rcu_read_lock_bh(); 1067 return get_idx(seq_file_net(s), s->private, *pos); 1068 } 1069 1070 static void *seq_next(struct seq_file *s, void *v, loff_t *pos) 1071 { 1072 (*pos)++; 1073 return get_next(seq_file_net(s), s->private, v); 1074 } 1075 1076 static void seq_stop(struct seq_file *s, void *v) 1077 __releases(rcu_bh) 1078 { 1079 rcu_read_unlock_bh(); 1080 } 1081 1082 static int seq_show(struct seq_file *s, void *v) 1083 { 1084 const struct nfulnl_instance *inst = v; 1085 1086 seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n", 1087 inst->group_num, 1088 inst->peer_portid, inst->qlen, 1089 inst->copy_mode, inst->copy_range, 1090 inst->flushtimeout, refcount_read(&inst->use)); 1091 1092 return 0; 1093 } 1094 1095 static const struct seq_operations nful_seq_ops = { 1096 .start = seq_start, 1097 .next = seq_next, 1098 .stop = seq_stop, 1099 .show = seq_show, 1100 }; 1101 #endif /* PROC_FS */ 1102 1103 static int __net_init nfnl_log_net_init(struct net *net) 1104 { 1105 unsigned int i; 1106 struct nfnl_log_net *log = nfnl_log_pernet(net); 1107 #ifdef CONFIG_PROC_FS 1108 struct proc_dir_entry *proc; 1109 kuid_t root_uid; 1110 kgid_t root_gid; 1111 #endif 1112 1113 for (i = 0; i < INSTANCE_BUCKETS; i++) 1114 INIT_HLIST_HEAD(&log->instance_table[i]); 1115 spin_lock_init(&log->instances_lock); 1116 1117 #ifdef CONFIG_PROC_FS 1118 proc = proc_create_net("nfnetlink_log", 0440, net->nf.proc_netfilter, 1119 &nful_seq_ops, sizeof(struct iter_state)); 1120 if (!proc) 1121 return -ENOMEM; 1122 1123 root_uid = make_kuid(net->user_ns, 0); 1124 root_gid = make_kgid(net->user_ns, 0); 1125 if (uid_valid(root_uid) && gid_valid(root_gid)) 1126 proc_set_user(proc, root_uid, root_gid); 1127 #endif 1128 return 0; 1129 } 1130 1131 static void __net_exit nfnl_log_net_exit(struct net *net) 1132 { 1133 struct nfnl_log_net *log = nfnl_log_pernet(net); 1134 unsigned int i; 1135 1136 #ifdef CONFIG_PROC_FS 1137 remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter); 1138 #endif 1139 nf_log_unset(net, &nfulnl_logger); 1140 for (i = 0; i < INSTANCE_BUCKETS; i++) 1141 WARN_ON_ONCE(!hlist_empty(&log->instance_table[i])); 1142 } 1143 1144 static struct pernet_operations nfnl_log_net_ops = { 1145 .init = nfnl_log_net_init, 1146 .exit = nfnl_log_net_exit, 1147 .id = &nfnl_log_net_id, 1148 .size = sizeof(struct nfnl_log_net), 1149 }; 1150 1151 static int __init nfnetlink_log_init(void) 1152 { 1153 int status; 1154 1155 status = register_pernet_subsys(&nfnl_log_net_ops); 1156 if (status < 0) { 1157 pr_err("failed to register pernet ops\n"); 1158 goto out; 1159 } 1160 1161 netlink_register_notifier(&nfulnl_rtnl_notifier); 1162 status = nfnetlink_subsys_register(&nfulnl_subsys); 1163 if (status < 0) { 1164 pr_err("failed to create netlink socket\n"); 1165 goto cleanup_netlink_notifier; 1166 } 1167 1168 status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger); 1169 if (status < 0) { 1170 pr_err("failed to register logger\n"); 1171 goto cleanup_subsys; 1172 } 1173 1174 return status; 1175 1176 cleanup_subsys: 1177 nfnetlink_subsys_unregister(&nfulnl_subsys); 1178 cleanup_netlink_notifier: 1179 netlink_unregister_notifier(&nfulnl_rtnl_notifier); 1180 unregister_pernet_subsys(&nfnl_log_net_ops); 1181 out: 1182 return status; 1183 } 1184 1185 static void __exit nfnetlink_log_fini(void) 1186 { 1187 nfnetlink_subsys_unregister(&nfulnl_subsys); 1188 netlink_unregister_notifier(&nfulnl_rtnl_notifier); 1189 unregister_pernet_subsys(&nfnl_log_net_ops); 1190 nf_log_unregister(&nfulnl_logger); 1191 } 1192 1193 MODULE_DESCRIPTION("netfilter userspace logging"); 1194 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); 1195 MODULE_LICENSE("GPL"); 1196 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG); 1197 MODULE_ALIAS_NF_LOGGER(AF_INET, 1); 1198 MODULE_ALIAS_NF_LOGGER(AF_INET6, 1); 1199 MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1); 1200 MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */ 1201 MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */ 1202 1203 module_init(nfnetlink_log_init); 1204 module_exit(nfnetlink_log_fini); 1205