1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * INET		An implementation of the TCP/IP protocol suite for the LINUX
   4 *		operating system.  INET is implemented using the  BSD Socket
   5 *		interface as the means of communication with the user level.
   6 *
   7 *		"Ping" sockets
   8 *
   9 * Based on ipv4/udp.c code.
  10 *
  11 * Authors:	Vasiliy Kulikov / Openwall (for Linux 2.6),
  12 *		Pavel Kankovsky (for Linux 2.4.32)
  13 *
  14 * Pavel gave all rights to bugs to Vasiliy,
  15 * none of the bugs are Pavel's now.
  16 */
  17
  18#include <linux/uaccess.h>
  19#include <linux/types.h>
  20#include <linux/fcntl.h>
  21#include <linux/socket.h>
  22#include <linux/sockios.h>
  23#include <linux/in.h>
  24#include <linux/errno.h>
  25#include <linux/timer.h>
  26#include <linux/mm.h>
  27#include <linux/inet.h>
  28#include <linux/netdevice.h>
  29#include <net/snmp.h>
  30#include <net/ip.h>
  31#include <net/icmp.h>
  32#include <net/protocol.h>
  33#include <linux/skbuff.h>
  34#include <linux/proc_fs.h>
  35#include <linux/export.h>
  36#include <linux/bpf-cgroup.h>
  37#include <net/sock.h>
  38#include <net/ping.h>
  39#include <net/udp.h>
  40#include <net/route.h>
  41#include <net/inet_common.h>
  42#include <net/checksum.h>
  43
  44#if IS_ENABLED(CONFIG_IPV6)
  45#include <linux/in6.h>
  46#include <linux/icmpv6.h>
  47#include <net/addrconf.h>
  48#include <net/ipv6.h>
  49#include <net/transp_v6.h>
  50#endif
  51
  52struct ping_table {
  53	struct hlist_head	hash[PING_HTABLE_SIZE];
  54	spinlock_t		lock;
  55};
  56
  57static struct ping_table ping_table;
  58struct pingv6_ops pingv6_ops;
  59EXPORT_SYMBOL_GPL(pingv6_ops);
  60
  61static u16 ping_port_rover;
  62
  63static inline u32 ping_hashfn(const struct net *net, u32 num, u32 mask)
  64{
  65	u32 res = (num + net_hash_mix(net)) & mask;
  66
  67	pr_debug("hash(%u) = %u\n", num, res);
  68	return res;
  69}
  70EXPORT_SYMBOL_GPL(ping_hash);
  71
  72static inline struct hlist_head *ping_hashslot(struct ping_table *table,
  73					       struct net *net, unsigned int num)
  74{
  75	return &table->hash[ping_hashfn(net, num, PING_HTABLE_MASK)];
  76}
  77
  78int ping_get_port(struct sock *sk, unsigned short ident)
  79{
  80	struct inet_sock *isk, *isk2;
  81	struct hlist_head *hlist;
  82	struct sock *sk2 = NULL;
  83
  84	isk = inet_sk(sk);
  85	spin_lock(&ping_table.lock);
  86	if (ident == 0) {
  87		u32 i;
  88		u16 result = ping_port_rover + 1;
  89
  90		for (i = 0; i < (1L << 16); i++, result++) {
  91			if (!result)
  92				result++; /* avoid zero */
  93			hlist = ping_hashslot(&ping_table, sock_net(sk),
  94					    result);
  95			sk_for_each(sk2, hlist) {
  96				isk2 = inet_sk(sk2);
  97
  98				if (isk2->inet_num == result)
  99					goto next_port;
 100			}
 101
 102			/* found */
 103			ping_port_rover = ident = result;
 104			break;
 105next_port:
 106			;
 107		}
 108		if (i >= (1L << 16))
 109			goto fail;
 110	} else {
 111		hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
 112		sk_for_each(sk2, hlist) {
 113			isk2 = inet_sk(sk2);
 114
 115			/* BUG? Why is this reuse and not reuseaddr? ping.c
 116			 * doesn't turn off SO_REUSEADDR, and it doesn't expect
 117			 * that other ping processes can steal its packets.
 118			 */
 119			if ((isk2->inet_num == ident) &&
 120			    (sk2 != sk) &&
 121			    (!sk2->sk_reuse || !sk->sk_reuse))
 122				goto fail;
 123		}
 124	}
 125
 126	pr_debug("found port/ident = %d\n", ident);
 127	isk->inet_num = ident;
 128	if (sk_unhashed(sk)) {
 129		pr_debug("was not hashed\n");
 130		sk_add_node_rcu(sk, hlist);
 131		sock_set_flag(sk, SOCK_RCU_FREE);
 132		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 133	}
 134	spin_unlock(&ping_table.lock);
 135	return 0;
 136
 137fail:
 138	spin_unlock(&ping_table.lock);
 139	return -EADDRINUSE;
 140}
 141EXPORT_SYMBOL_GPL(ping_get_port);
 142
 143int ping_hash(struct sock *sk)
 144{
 145	pr_debug("ping_hash(sk->port=%u)\n", inet_sk(sk)->inet_num);
 146	BUG(); /* "Please do not press this button again." */
 147
 148	return 0;
 149}
 150
 151void ping_unhash(struct sock *sk)
 152{
 153	struct inet_sock *isk = inet_sk(sk);
 154
 155	pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
 156	spin_lock(&ping_table.lock);
 157	if (sk_del_node_init_rcu(sk)) {
 158		isk->inet_num = 0;
 159		isk->inet_sport = 0;
 160		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 161	}
 162	spin_unlock(&ping_table.lock);
 163}
 164EXPORT_SYMBOL_GPL(ping_unhash);
 165
 166/* Called under rcu_read_lock() */
 167static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 168{
 169	struct hlist_head *hslot = ping_hashslot(&ping_table, net, ident);
 170	struct sock *sk = NULL;
 171	struct inet_sock *isk;
 172	int dif, sdif;
 173
 174	if (skb->protocol == htons(ETH_P_IP)) {
 175		dif = inet_iif(skb);
 176		sdif = inet_sdif(skb);
 177		pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
 178			 (int)ident, &ip_hdr(skb)->daddr, dif);
 179#if IS_ENABLED(CONFIG_IPV6)
 180	} else if (skb->protocol == htons(ETH_P_IPV6)) {
 181		dif = inet6_iif(skb);
 182		sdif = inet6_sdif(skb);
 183		pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 184			 (int)ident, &ipv6_hdr(skb)->daddr, dif);
 185#endif
 186	} else {
 187		return NULL;
 188	}
 189
 190	sk_for_each_rcu(sk, hslot) {
 191		isk = inet_sk(sk);
 192
 193		pr_debug("iterate\n");
 194		if (isk->inet_num != ident)
 195			continue;
 196
 197		if (skb->protocol == htons(ETH_P_IP) &&
 198		    sk->sk_family == AF_INET) {
 199			pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 200				 (int) isk->inet_num, &isk->inet_rcv_saddr,
 201				 sk->sk_bound_dev_if);
 202
 203			if (isk->inet_rcv_saddr &&
 204			    isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 205				continue;
 206#if IS_ENABLED(CONFIG_IPV6)
 207		} else if (skb->protocol == htons(ETH_P_IPV6) &&
 208			   sk->sk_family == AF_INET6) {
 209
 210			pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 211				 (int) isk->inet_num,
 212				 &sk->sk_v6_rcv_saddr,
 213				 sk->sk_bound_dev_if);
 214
 215			if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 216			    !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 217					     &ipv6_hdr(skb)->daddr))
 218				continue;
 219#endif
 220		} else {
 221			continue;
 222		}
 223
 224		if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif &&
 225		    sk->sk_bound_dev_if != sdif)
 226			continue;
 227
 228		goto exit;
 229	}
 230
 231	sk = NULL;
 232exit:
 233
 234	return sk;
 235}
 236
 237static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 238					  kgid_t *high)
 239{
 240	kgid_t *data = net->ipv4.ping_group_range.range;
 241	unsigned int seq;
 242
 243	do {
 244		seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 245
 246		*low = data[0];
 247		*high = data[1];
 248	} while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 249}
 250
 251
 252int ping_init_sock(struct sock *sk)
 253{
 254	struct net *net = sock_net(sk);
 255	kgid_t group = current_egid();
 256	struct group_info *group_info;
 257	int i;
 258	kgid_t low, high;
 259	int ret = 0;
 260
 261	if (sk->sk_family == AF_INET6)
 262		sk->sk_ipv6only = 1;
 263
 264	inet_get_ping_group_range_net(net, &low, &high);
 265	if (gid_lte(low, group) && gid_lte(group, high))
 266		return 0;
 267
 268	group_info = get_current_groups();
 269	for (i = 0; i < group_info->ngroups; i++) {
 270		kgid_t gid = group_info->gid[i];
 271
 272		if (gid_lte(low, gid) && gid_lte(gid, high))
 273			goto out_release_group;
 274	}
 275
 276	ret = -EACCES;
 277
 278out_release_group:
 279	put_group_info(group_info);
 280	return ret;
 281}
 282EXPORT_SYMBOL_GPL(ping_init_sock);
 283
 284void ping_close(struct sock *sk, long timeout)
 285{
 286	pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 287		 inet_sk(sk), inet_sk(sk)->inet_num);
 288	pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
 289
 290	sk_common_release(sk);
 291}
 292EXPORT_SYMBOL_GPL(ping_close);
 293
 294static int ping_pre_connect(struct sock *sk, struct sockaddr *uaddr,
 295			    int addr_len)
 296{
 297	/* This check is replicated from __ip4_datagram_connect() and
 298	 * intended to prevent BPF program called below from accessing bytes
 299	 * that are out of the bound specified by user in addr_len.
 300	 */
 301	if (addr_len < sizeof(struct sockaddr_in))
 302		return -EINVAL;
 303
 304	return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr, &addr_len);
 305}
 306
 307/* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 308static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 309				struct sockaddr *uaddr, int addr_len)
 310{
 311	struct net *net = sock_net(sk);
 312	if (sk->sk_family == AF_INET) {
 313		struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 314		u32 tb_id = RT_TABLE_LOCAL;
 315		int chk_addr_ret;
 316
 317		if (addr_len < sizeof(*addr))
 318			return -EINVAL;
 319
 320		if (addr->sin_family != AF_INET &&
 321		    !(addr->sin_family == AF_UNSPEC &&
 322		      addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 323			return -EAFNOSUPPORT;
 324
 325		pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 326			 sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 327
 328		if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 329			return 0;
 330
 331		tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ? : tb_id;
 332		chk_addr_ret = inet_addr_type_table(net, addr->sin_addr.s_addr, tb_id);
 333
 334		if (chk_addr_ret == RTN_MULTICAST ||
 335		    chk_addr_ret == RTN_BROADCAST ||
 336		    (chk_addr_ret != RTN_LOCAL &&
 337		     !inet_can_nonlocal_bind(net, isk)))
 338			return -EADDRNOTAVAIL;
 339
 340#if IS_ENABLED(CONFIG_IPV6)
 341	} else if (sk->sk_family == AF_INET6) {
 342		struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 343		int addr_type, scoped, has_addr;
 344		struct net_device *dev = NULL;
 345
 346		if (addr_len < sizeof(*addr))
 347			return -EINVAL;
 348
 349		if (addr->sin6_family != AF_INET6)
 350			return -EAFNOSUPPORT;
 351
 352		pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 353			 sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 354
 355		addr_type = ipv6_addr_type(&addr->sin6_addr);
 356		scoped = __ipv6_addr_needs_scope_id(addr_type);
 357		if ((addr_type != IPV6_ADDR_ANY &&
 358		     !(addr_type & IPV6_ADDR_UNICAST)) ||
 359		    (scoped && !addr->sin6_scope_id))
 360			return -EINVAL;
 361
 362		rcu_read_lock();
 363		if (addr->sin6_scope_id) {
 364			dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 365			if (!dev) {
 366				rcu_read_unlock();
 367				return -ENODEV;
 368			}
 369		}
 370
 371		if (!dev && sk->sk_bound_dev_if) {
 372			dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
 373			if (!dev) {
 374				rcu_read_unlock();
 375				return -ENODEV;
 376			}
 377		}
 378		has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 379						    scoped);
 380		rcu_read_unlock();
 381
 382		if (!(ipv6_can_nonlocal_bind(net, isk) || has_addr ||
 383		      addr_type == IPV6_ADDR_ANY))
 384			return -EADDRNOTAVAIL;
 385
 386		if (scoped)
 387			sk->sk_bound_dev_if = addr->sin6_scope_id;
 388#endif
 389	} else {
 390		return -EAFNOSUPPORT;
 391	}
 392	return 0;
 393}
 394
 395static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 396{
 397	if (saddr->sa_family == AF_INET) {
 398		struct inet_sock *isk = inet_sk(sk);
 399		struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 400		isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 401#if IS_ENABLED(CONFIG_IPV6)
 402	} else if (saddr->sa_family == AF_INET6) {
 403		struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 404		struct ipv6_pinfo *np = inet6_sk(sk);
 405		sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 406#endif
 407	}
 408}
 409
 410/*
 411 * We need our own bind because there are no privileged id's == local ports.
 412 * Moreover, we don't allow binding to multi- and broadcast addresses.
 413 */
 414
 415int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 416{
 417	struct inet_sock *isk = inet_sk(sk);
 418	unsigned short snum;
 419	int err;
 420	int dif = sk->sk_bound_dev_if;
 421
 422	err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 423	if (err)
 424		return err;
 425
 426	lock_sock(sk);
 427
 428	err = -EINVAL;
 429	if (isk->inet_num != 0)
 430		goto out;
 431
 432	err = -EADDRINUSE;
 433	snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 434	if (ping_get_port(sk, snum) != 0) {
 435		/* Restore possibly modified sk->sk_bound_dev_if by ping_check_bind_addr(). */
 436		sk->sk_bound_dev_if = dif;
 437		goto out;
 438	}
 439	ping_set_saddr(sk, uaddr);
 440
 441	pr_debug("after bind(): num = %hu, dif = %d\n",
 442		 isk->inet_num,
 443		 sk->sk_bound_dev_if);
 444
 445	err = 0;
 446	if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 447		sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 448#if IS_ENABLED(CONFIG_IPV6)
 449	if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 450		sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 451#endif
 452
 453	if (snum)
 454		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 455	isk->inet_sport = htons(isk->inet_num);
 456	isk->inet_daddr = 0;
 457	isk->inet_dport = 0;
 458
 459#if IS_ENABLED(CONFIG_IPV6)
 460	if (sk->sk_family == AF_INET6)
 461		memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 462#endif
 463
 464	sk_dst_reset(sk);
 465out:
 466	release_sock(sk);
 467	pr_debug("ping_v4_bind -> %d\n", err);
 468	return err;
 469}
 470EXPORT_SYMBOL_GPL(ping_bind);
 471
 472/*
 473 * Is this a supported type of ICMP message?
 474 */
 475
 476static inline int ping_supported(int family, int type, int code)
 477{
 478	return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 479	       (family == AF_INET && type == ICMP_EXT_ECHO && code == 0) ||
 480	       (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0) ||
 481	       (family == AF_INET6 && type == ICMPV6_EXT_ECHO_REQUEST && code == 0);
 482}
 483
 484/*
 485 * This routine is called by the ICMP module when it gets some
 486 * sort of error condition.
 487 */
 488
 489void ping_err(struct sk_buff *skb, int offset, u32 info)
 490{
 491	int family;
 492	struct icmphdr *icmph;
 493	struct inet_sock *inet_sock;
 494	int type;
 495	int code;
 496	struct net *net = dev_net(skb->dev);
 497	struct sock *sk;
 498	int harderr;
 499	int err;
 500
 501	if (skb->protocol == htons(ETH_P_IP)) {
 502		family = AF_INET;
 503		type = icmp_hdr(skb)->type;
 504		code = icmp_hdr(skb)->code;
 505		icmph = (struct icmphdr *)(skb->data + offset);
 506	} else if (skb->protocol == htons(ETH_P_IPV6)) {
 507		family = AF_INET6;
 508		type = icmp6_hdr(skb)->icmp6_type;
 509		code = icmp6_hdr(skb)->icmp6_code;
 510		icmph = (struct icmphdr *) (skb->data + offset);
 511	} else {
 512		BUG();
 513	}
 514
 515	/* We assume the packet has already been checked by icmp_unreach */
 516
 517	if (!ping_supported(family, icmph->type, icmph->code))
 518		return;
 519
 520	pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 521		 skb->protocol, type, code, ntohs(icmph->un.echo.id),
 522		 ntohs(icmph->un.echo.sequence));
 523
 524	sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 525	if (!sk) {
 526		pr_debug("no socket, dropping\n");
 527		return;	/* No socket for error */
 528	}
 529	pr_debug("err on socket %p\n", sk);
 530
 531	err = 0;
 532	harderr = 0;
 533	inet_sock = inet_sk(sk);
 534
 535	if (skb->protocol == htons(ETH_P_IP)) {
 536		switch (type) {
 537		default:
 538		case ICMP_TIME_EXCEEDED:
 539			err = EHOSTUNREACH;
 540			break;
 541		case ICMP_SOURCE_QUENCH:
 542			/* This is not a real error but ping wants to see it.
 543			 * Report it with some fake errno.
 544			 */
 545			err = EREMOTEIO;
 546			break;
 547		case ICMP_PARAMETERPROB:
 548			err = EPROTO;
 549			harderr = 1;
 550			break;
 551		case ICMP_DEST_UNREACH:
 552			if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 553				ipv4_sk_update_pmtu(skb, sk, info);
 554				if (READ_ONCE(inet_sock->pmtudisc) != IP_PMTUDISC_DONT) {
 555					err = EMSGSIZE;
 556					harderr = 1;
 557					break;
 558				}
 559				goto out;
 560			}
 561			err = EHOSTUNREACH;
 562			if (code <= NR_ICMP_UNREACH) {
 563				harderr = icmp_err_convert[code].fatal;
 564				err = icmp_err_convert[code].errno;
 565			}
 566			break;
 567		case ICMP_REDIRECT:
 568			/* See ICMP_SOURCE_QUENCH */
 569			ipv4_sk_redirect(skb, sk);
 570			err = EREMOTEIO;
 571			break;
 572		}
 573#if IS_ENABLED(CONFIG_IPV6)
 574	} else if (skb->protocol == htons(ETH_P_IPV6)) {
 575		harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 576#endif
 577	}
 578
 579	/*
 580	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
 581	 *	4.1.3.3.
 582	 */
 583	if ((family == AF_INET && !inet_test_bit(RECVERR, sk)) ||
 584	    (family == AF_INET6 && !inet6_test_bit(RECVERR6, sk))) {
 585		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 586			goto out;
 587	} else {
 588		if (family == AF_INET) {
 589			ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 590				      info, (u8 *)icmph);
 591#if IS_ENABLED(CONFIG_IPV6)
 592		} else if (family == AF_INET6) {
 593			pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 594						   info, (u8 *)icmph);
 595#endif
 596		}
 597	}
 598	sk->sk_err = err;
 599	sk_error_report(sk);
 600out:
 601	return;
 602}
 603EXPORT_SYMBOL_GPL(ping_err);
 604
 605/*
 606 *	Copy and checksum an ICMP Echo packet from user space into a buffer
 607 *	starting from the payload.
 608 */
 609
 610int ping_getfrag(void *from, char *to,
 611		 int offset, int fraglen, int odd, struct sk_buff *skb)
 612{
 613	struct pingfakehdr *pfh = from;
 614
 615	if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
 616					  &pfh->msg->msg_iter))
 617		return -EFAULT;
 618
 619#if IS_ENABLED(CONFIG_IPV6)
 620	/* For IPv6, checksum each skb as we go along, as expected by
 621	 * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 622	 * wcheck, it will be finalized in ping_v4_push_pending_frames.
 623	 */
 624	if (pfh->family == AF_INET6) {
 625		skb->csum = csum_block_add(skb->csum, pfh->wcheck, odd);
 626		skb->ip_summed = CHECKSUM_NONE;
 627		pfh->wcheck = 0;
 628	}
 629#endif
 630
 631	return 0;
 632}
 633EXPORT_SYMBOL_GPL(ping_getfrag);
 634
 635static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 636				       struct flowi4 *fl4)
 637{
 638	struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 639
 640	if (!skb)
 641		return 0;
 642	pfh->wcheck = csum_partial((char *)&pfh->icmph,
 643		sizeof(struct icmphdr), pfh->wcheck);
 644	pfh->icmph.checksum = csum_fold(pfh->wcheck);
 645	memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 646	skb->ip_summed = CHECKSUM_NONE;
 647	return ip_push_pending_frames(sk, fl4);
 648}
 649
 650int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 651			void *user_icmph, size_t icmph_len)
 652{
 653	u8 type, code;
 654
 655	if (len > 0xFFFF)
 656		return -EMSGSIZE;
 657
 658	/* Must have at least a full ICMP header. */
 659	if (len < icmph_len)
 660		return -EINVAL;
 661
 662	/*
 663	 *	Check the flags.
 664	 */
 665
 666	/* Mirror BSD error message compatibility */
 667	if (msg->msg_flags & MSG_OOB)
 668		return -EOPNOTSUPP;
 669
 670	/*
 671	 *	Fetch the ICMP header provided by the userland.
 672	 *	iovec is modified! The ICMP header is consumed.
 673	 */
 674	if (memcpy_from_msg(user_icmph, msg, icmph_len))
 675		return -EFAULT;
 676
 677	if (family == AF_INET) {
 678		type = ((struct icmphdr *) user_icmph)->type;
 679		code = ((struct icmphdr *) user_icmph)->code;
 680#if IS_ENABLED(CONFIG_IPV6)
 681	} else if (family == AF_INET6) {
 682		type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 683		code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 684#endif
 685	} else {
 686		BUG();
 687	}
 688
 689	if (!ping_supported(family, type, code))
 690		return -EINVAL;
 691
 692	return 0;
 693}
 694EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 695
 696static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 697{
 698	struct net *net = sock_net(sk);
 699	struct flowi4 fl4;
 700	struct inet_sock *inet = inet_sk(sk);
 701	struct ipcm_cookie ipc;
 702	struct icmphdr user_icmph;
 703	struct pingfakehdr pfh;
 704	struct rtable *rt = NULL;
 705	struct ip_options_data opt_copy;
 706	int free = 0;
 707	__be32 saddr, daddr, faddr;
 708	u8 tos, scope;
 709	int err;
 710
 711	pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 712
 713	err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 714				  sizeof(user_icmph));
 715	if (err)
 716		return err;
 717
 718	/*
 719	 *	Get and verify the address.
 720	 */
 721
 722	if (msg->msg_name) {
 723		DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 724		if (msg->msg_namelen < sizeof(*usin))
 725			return -EINVAL;
 726		if (usin->sin_family != AF_INET)
 727			return -EAFNOSUPPORT;
 728		daddr = usin->sin_addr.s_addr;
 729		/* no remote port */
 730	} else {
 731		if (sk->sk_state != TCP_ESTABLISHED)
 732			return -EDESTADDRREQ;
 733		daddr = inet->inet_daddr;
 734		/* no remote port */
 735	}
 736
 737	ipcm_init_sk(&ipc, inet);
 738
 739	if (msg->msg_controllen) {
 740		err = ip_cmsg_send(sk, msg, &ipc, false);
 741		if (unlikely(err)) {
 742			kfree(ipc.opt);
 743			return err;
 744		}
 745		if (ipc.opt)
 746			free = 1;
 747	}
 748	if (!ipc.opt) {
 749		struct ip_options_rcu *inet_opt;
 750
 751		rcu_read_lock();
 752		inet_opt = rcu_dereference(inet->inet_opt);
 753		if (inet_opt) {
 754			memcpy(&opt_copy, inet_opt,
 755			       sizeof(*inet_opt) + inet_opt->opt.optlen);
 756			ipc.opt = &opt_copy.opt;
 757		}
 758		rcu_read_unlock();
 759	}
 760
 761	saddr = ipc.addr;
 762	ipc.addr = faddr = daddr;
 763
 764	if (ipc.opt && ipc.opt->opt.srr) {
 765		if (!daddr) {
 766			err = -EINVAL;
 767			goto out_free;
 768		}
 769		faddr = ipc.opt->opt.faddr;
 770	}
 771	tos = get_rttos(&ipc, inet);
 772	scope = ip_sendmsg_scope(inet, &ipc, msg);
 773
 774	if (ipv4_is_multicast(daddr)) {
 775		if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
 776			ipc.oif = READ_ONCE(inet->mc_index);
 777		if (!saddr)
 778			saddr = READ_ONCE(inet->mc_addr);
 779	} else if (!ipc.oif)
 780		ipc.oif = READ_ONCE(inet->uc_index);
 781
 782	flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos, scope,
 783			   sk->sk_protocol, inet_sk_flowi_flags(sk), faddr,
 784			   saddr, 0, 0, sk->sk_uid);
 785
 786	fl4.fl4_icmp_type = user_icmph.type;
 787	fl4.fl4_icmp_code = user_icmph.code;
 788
 789	security_sk_classify_flow(sk, flowi4_to_flowi_common(&fl4));
 790	rt = ip_route_output_flow(net, &fl4, sk);
 791	if (IS_ERR(rt)) {
 792		err = PTR_ERR(rt);
 793		rt = NULL;
 794		if (err == -ENETUNREACH)
 795			IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 796		goto out;
 797	}
 798
 799	err = -EACCES;
 800	if ((rt->rt_flags & RTCF_BROADCAST) &&
 801	    !sock_flag(sk, SOCK_BROADCAST))
 802		goto out;
 803
 804	if (msg->msg_flags & MSG_CONFIRM)
 805		goto do_confirm;
 806back_from_confirm:
 807
 808	if (!ipc.addr)
 809		ipc.addr = fl4.daddr;
 810
 811	lock_sock(sk);
 812
 813	pfh.icmph.type = user_icmph.type; /* already checked */
 814	pfh.icmph.code = user_icmph.code; /* ditto */
 815	pfh.icmph.checksum = 0;
 816	pfh.icmph.un.echo.id = inet->inet_sport;
 817	pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 818	pfh.msg = msg;
 819	pfh.wcheck = 0;
 820	pfh.family = AF_INET;
 821
 822	err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 823			     sizeof(struct icmphdr), &ipc, &rt,
 824			     msg->msg_flags);
 825	if (err)
 826		ip_flush_pending_frames(sk);
 827	else
 828		err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 829	release_sock(sk);
 830
 831out:
 832	ip_rt_put(rt);
 833out_free:
 834	if (free)
 835		kfree(ipc.opt);
 836	if (!err) {
 837		icmp_out_count(sock_net(sk), user_icmph.type);
 838		return len;
 839	}
 840	return err;
 841
 842do_confirm:
 843	if (msg->msg_flags & MSG_PROBE)
 844		dst_confirm_neigh(&rt->dst, &fl4.daddr);
 845	if (!(msg->msg_flags & MSG_PROBE) || len)
 846		goto back_from_confirm;
 847	err = 0;
 848	goto out;
 849}
 850
 851int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
 852		 int *addr_len)
 853{
 854	struct inet_sock *isk = inet_sk(sk);
 855	int family = sk->sk_family;
 856	struct sk_buff *skb;
 857	int copied, err;
 858
 859	pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 860
 861	err = -EOPNOTSUPP;
 862	if (flags & MSG_OOB)
 863		goto out;
 864
 865	if (flags & MSG_ERRQUEUE)
 866		return inet_recv_error(sk, msg, len, addr_len);
 867
 868	skb = skb_recv_datagram(sk, flags, &err);
 869	if (!skb)
 870		goto out;
 871
 872	copied = skb->len;
 873	if (copied > len) {
 874		msg->msg_flags |= MSG_TRUNC;
 875		copied = len;
 876	}
 877
 878	/* Don't bother checking the checksum */
 879	err = skb_copy_datagram_msg(skb, 0, msg, copied);
 880	if (err)
 881		goto done;
 882
 883	sock_recv_timestamp(msg, sk, skb);
 884
 885	/* Copy the address and add cmsg data. */
 886	if (family == AF_INET) {
 887		DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 888
 889		if (sin) {
 890			sin->sin_family = AF_INET;
 891			sin->sin_port = 0 /* skb->h.uh->source */;
 892			sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 893			memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 894			*addr_len = sizeof(*sin);
 895		}
 896
 897		if (inet_cmsg_flags(isk))
 898			ip_cmsg_recv(msg, skb);
 899
 900#if IS_ENABLED(CONFIG_IPV6)
 901	} else if (family == AF_INET6) {
 902		struct ipv6hdr *ip6 = ipv6_hdr(skb);
 903		DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 904
 905		if (sin6) {
 906			sin6->sin6_family = AF_INET6;
 907			sin6->sin6_port = 0;
 908			sin6->sin6_addr = ip6->saddr;
 909			sin6->sin6_flowinfo = 0;
 910			if (inet6_test_bit(SNDFLOW, sk))
 911				sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 912			sin6->sin6_scope_id =
 913				ipv6_iface_scope_id(&sin6->sin6_addr,
 914						    inet6_iif(skb));
 915			*addr_len = sizeof(*sin6);
 916		}
 917
 918		if (inet6_sk(sk)->rxopt.all)
 919			pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 920		if (skb->protocol == htons(ETH_P_IPV6) &&
 921		    inet6_sk(sk)->rxopt.all)
 922			pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 923		else if (skb->protocol == htons(ETH_P_IP) &&
 924			 inet_cmsg_flags(isk))
 925			ip_cmsg_recv(msg, skb);
 926#endif
 927	} else {
 928		BUG();
 929	}
 930
 931	err = copied;
 932
 933done:
 934	skb_free_datagram(sk, skb);
 935out:
 936	pr_debug("ping_recvmsg -> %d\n", err);
 937	return err;
 938}
 939EXPORT_SYMBOL_GPL(ping_recvmsg);
 940
 941static enum skb_drop_reason __ping_queue_rcv_skb(struct sock *sk,
 942						 struct sk_buff *skb)
 943{
 944	enum skb_drop_reason reason;
 945
 946	pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 947		 inet_sk(sk), inet_sk(sk)->inet_num, skb);
 948	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
 949		sk_skb_reason_drop(sk, skb, reason);
 950		pr_debug("ping_queue_rcv_skb -> failed\n");
 951		return reason;
 952	}
 953	return SKB_NOT_DROPPED_YET;
 954}
 955
 956int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 957{
 958	return __ping_queue_rcv_skb(sk, skb) ? -1 : 0;
 959}
 960EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 961
 962
 963/*
 964 *	All we need to do is get the socket.
 965 */
 966
 967enum skb_drop_reason ping_rcv(struct sk_buff *skb)
 968{
 969	enum skb_drop_reason reason = SKB_DROP_REASON_NO_SOCKET;
 970	struct sock *sk;
 971	struct net *net = dev_net(skb->dev);
 972	struct icmphdr *icmph = icmp_hdr(skb);
 973
 974	/* We assume the packet has already been checked by icmp_rcv */
 975
 976	pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 977		 skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 978
 979	/* Push ICMP header back */
 980	skb_push(skb, skb->data - (u8 *)icmph);
 981
 982	sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 983	if (sk) {
 984		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 985
 986		pr_debug("rcv on socket %p\n", sk);
 987		if (skb2)
 988			reason = __ping_queue_rcv_skb(sk, skb2);
 989		else
 990			reason = SKB_DROP_REASON_NOMEM;
 991	}
 992
 993	if (reason)
 994		pr_debug("no socket, dropping\n");
 995
 996	return reason;
 997}
 998EXPORT_SYMBOL_GPL(ping_rcv);
 999
1000struct proto ping_prot = {
1001	.name =		"PING",
1002	.owner =	THIS_MODULE,
1003	.init =		ping_init_sock,
1004	.close =	ping_close,
1005	.pre_connect =	ping_pre_connect,
1006	.connect =	ip4_datagram_connect,
1007	.disconnect =	__udp_disconnect,
1008	.setsockopt =	ip_setsockopt,
1009	.getsockopt =	ip_getsockopt,
1010	.sendmsg =	ping_v4_sendmsg,
1011	.recvmsg =	ping_recvmsg,
1012	.bind =		ping_bind,
1013	.backlog_rcv =	ping_queue_rcv_skb,
1014	.release_cb =	ip4_datagram_release_cb,
1015	.hash =		ping_hash,
1016	.unhash =	ping_unhash,
1017	.get_port =	ping_get_port,
1018	.put_port =	ping_unhash,
1019	.obj_size =	sizeof(struct inet_sock),
1020};
1021EXPORT_SYMBOL(ping_prot);
1022
1023#ifdef CONFIG_PROC_FS
1024
1025static struct sock *ping_get_first(struct seq_file *seq, int start)
1026{
1027	struct sock *sk;
1028	struct ping_iter_state *state = seq->private;
1029	struct net *net = seq_file_net(seq);
1030
1031	for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1032	     ++state->bucket) {
1033		struct hlist_head *hslot;
1034
1035		hslot = &ping_table.hash[state->bucket];
1036
1037		if (hlist_empty(hslot))
1038			continue;
1039
1040		sk_for_each(sk, hslot) {
1041			if (net_eq(sock_net(sk), net) &&
1042			    sk->sk_family == state->family)
1043				goto found;
1044		}
1045	}
1046	sk = NULL;
1047found:
1048	return sk;
1049}
1050
1051static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1052{
1053	struct ping_iter_state *state = seq->private;
1054	struct net *net = seq_file_net(seq);
1055
1056	do {
1057		sk = sk_next(sk);
1058	} while (sk && (!net_eq(sock_net(sk), net)));
1059
1060	if (!sk)
1061		return ping_get_first(seq, state->bucket + 1);
1062	return sk;
1063}
1064
1065static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1066{
1067	struct sock *sk = ping_get_first(seq, 0);
1068
1069	if (sk)
1070		while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1071			--pos;
1072	return pos ? NULL : sk;
1073}
1074
1075void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1076	__acquires(ping_table.lock)
1077{
1078	struct ping_iter_state *state = seq->private;
1079	state->bucket = 0;
1080	state->family = family;
1081
1082	spin_lock(&ping_table.lock);
1083
1084	return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1085}
1086EXPORT_SYMBOL_GPL(ping_seq_start);
1087
1088static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1089{
1090	return ping_seq_start(seq, pos, AF_INET);
1091}
1092
1093void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1094{
1095	struct sock *sk;
1096
1097	if (v == SEQ_START_TOKEN)
1098		sk = ping_get_idx(seq, 0);
1099	else
1100		sk = ping_get_next(seq, v);
1101
1102	++*pos;
1103	return sk;
1104}
1105EXPORT_SYMBOL_GPL(ping_seq_next);
1106
1107void ping_seq_stop(struct seq_file *seq, void *v)
1108	__releases(ping_table.lock)
1109{
1110	spin_unlock(&ping_table.lock);
1111}
1112EXPORT_SYMBOL_GPL(ping_seq_stop);
1113
1114static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1115		int bucket)
1116{
1117	struct inet_sock *inet = inet_sk(sp);
1118	__be32 dest = inet->inet_daddr;
1119	__be32 src = inet->inet_rcv_saddr;
1120	__u16 destp = ntohs(inet->inet_dport);
1121	__u16 srcp = ntohs(inet->inet_sport);
1122
1123	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1124		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
1125		bucket, src, srcp, dest, destp, sp->sk_state,
1126		sk_wmem_alloc_get(sp),
1127		sk_rmem_alloc_get(sp),
1128		0, 0L, 0,
1129		from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1130		0, sock_i_ino(sp),
1131		refcount_read(&sp->sk_refcnt), sp,
1132		atomic_read(&sp->sk_drops));
1133}
1134
1135static int ping_v4_seq_show(struct seq_file *seq, void *v)
1136{
1137	seq_setwidth(seq, 127);
1138	if (v == SEQ_START_TOKEN)
1139		seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1140			   "rx_queue tr tm->when retrnsmt   uid  timeout "
1141			   "inode ref pointer drops");
1142	else {
1143		struct ping_iter_state *state = seq->private;
1144
1145		ping_v4_format_sock(v, seq, state->bucket);
1146	}
1147	seq_pad(seq, '\n');
1148	return 0;
1149}
1150
1151static const struct seq_operations ping_v4_seq_ops = {
1152	.start		= ping_v4_seq_start,
1153	.show		= ping_v4_seq_show,
1154	.next		= ping_seq_next,
1155	.stop		= ping_seq_stop,
1156};
1157
1158static int __net_init ping_v4_proc_init_net(struct net *net)
1159{
1160	if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
1161			sizeof(struct ping_iter_state)))
1162		return -ENOMEM;
1163	return 0;
1164}
1165
1166static void __net_exit ping_v4_proc_exit_net(struct net *net)
1167{
1168	remove_proc_entry("icmp", net->proc_net);
1169}
1170
1171static struct pernet_operations ping_v4_net_ops = {
1172	.init = ping_v4_proc_init_net,
1173	.exit = ping_v4_proc_exit_net,
1174};
1175
1176int __init ping_proc_init(void)
1177{
1178	return register_pernet_subsys(&ping_v4_net_ops);
1179}
1180
1181void ping_proc_exit(void)
1182{
1183	unregister_pernet_subsys(&ping_v4_net_ops);
1184}
1185
1186#endif
1187
1188void __init ping_init(void)
1189{
1190	int i;
1191
1192	for (i = 0; i < PING_HTABLE_SIZE; i++)
1193		INIT_HLIST_HEAD(&ping_table.hash[i]);
1194	spin_lock_init(&ping_table.lock);
1195}