net/ipv4/ping.c

   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 <net/sock.h>
  37 #include <net/ping.h>
  38 #include <net/udp.h>
  39 #include <net/route.h>
  40 #include <net/inet_common.h>
  41 #include <net/checksum.h>
  42
  43 #if IS_ENABLED(CONFIG_IPV6)
  44 #include <linux/in6.h>
  45 #include <linux/icmpv6.h>
  46 #include <net/addrconf.h>
  47 #include <net/ipv6.h>
  48 #include <net/transp_v6.h>
  49 #endif
  50
  51 struct ping_table {
  52         struct hlist_nulls_head hash[PING_HTABLE_SIZE];
  53         rwlock_t                lock;
  54 };
  55
  56 static struct ping_table ping_table;
  57 struct pingv6_ops pingv6_ops;
  58 EXPORT_SYMBOL_GPL(pingv6_ops);
  59
  60 static u16 ping_port_rover;
  61
  62 static inline u32 ping_hashfn(const struct net *net, u32 num, u32 mask)
  63 {
  64         u32 res = (num + net_hash_mix(net)) & mask;
  65
  66         pr_debug("hash(%u) = %u\n", num, res);
  67         return res;
  68 }
  69 EXPORT_SYMBOL_GPL(ping_hash);
  70
  71 static inline struct hlist_nulls_head *ping_hashslot(struct ping_table *table,
  72                                              struct net *net, unsigned int num)
  73 {
  74         return &table->hash[ping_hashfn(net, num, PING_HTABLE_MASK)];
  75 }
  76
  77 int ping_get_port(struct sock *sk, unsigned short ident)
  78 {
  79         struct hlist_nulls_node *node;
  80         struct hlist_nulls_head *hlist;
  81         struct inet_sock *isk, *isk2;
  82         struct sock *sk2 = NULL;
  83
  84         isk = inet_sk(sk);
  85         write_lock_bh(&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                         ping_portaddr_for_each_entry(sk2, node, 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;
 105 next_port:
 106                         ;
 107                 }
 108                 if (i >= (1L << 16))
 109                         goto fail;
 110         } else {
 111                 hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
 112                 ping_portaddr_for_each_entry(sk2, node, 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                 sock_hold(sk);
 131                 hlist_nulls_add_head(&sk->sk_nulls_node, hlist);
 132                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 133         }
 134         write_unlock_bh(&ping_table.lock);
 135         return 0;
 136
 137 fail:
 138         write_unlock_bh(&ping_table.lock);
 139         return 1;
 140 }
 141 EXPORT_SYMBOL_GPL(ping_get_port);
 142
 143 int 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
 151 void 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         write_lock_bh(&ping_table.lock);
 157         if (sk_hashed(sk)) {
 158                 hlist_nulls_del(&sk->sk_nulls_node);
 159                 sk_nulls_node_init(&sk->sk_nulls_node);
 160                 sock_put(sk);
 161                 isk->inet_num = 0;
 162                 isk->inet_sport = 0;
 163                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 164         }
 165         write_unlock_bh(&ping_table.lock);
 166 }
 167 EXPORT_SYMBOL_GPL(ping_unhash);
 168
 169 static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 170 {
 171         struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
 172         struct sock *sk = NULL;
 173         struct inet_sock *isk;
 174         struct hlist_nulls_node *hnode;
 175         int dif, sdif;
 176
 177         if (skb->protocol == htons(ETH_P_IP)) {
 178                 dif = inet_iif(skb);
 179                 sdif = inet_sdif(skb);
 180                 pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
 181                          (int)ident, &ip_hdr(skb)->daddr, dif);
 182 #if IS_ENABLED(CONFIG_IPV6)
 183         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 184                 dif = inet6_iif(skb);
 185                 sdif = inet6_sdif(skb);
 186                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 187                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
 188 #endif
 189         } else {
 190                 return NULL;
 191         }
 192
 193         read_lock_bh(&ping_table.lock);
 194
 195         ping_portaddr_for_each_entry(sk, hnode, hslot) {
 196                 isk = inet_sk(sk);
 197
 198                 pr_debug("iterate\n");
 199                 if (isk->inet_num != ident)
 200                         continue;
 201
 202                 if (skb->protocol == htons(ETH_P_IP) &&
 203                     sk->sk_family == AF_INET) {
 204                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 205                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
 206                                  sk->sk_bound_dev_if);
 207
 208                         if (isk->inet_rcv_saddr &&
 209                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 210                                 continue;
 211 #if IS_ENABLED(CONFIG_IPV6)
 212                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
 213                            sk->sk_family == AF_INET6) {
 214
 215                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 216                                  (int) isk->inet_num,
 217                                  &sk->sk_v6_rcv_saddr,
 218                                  sk->sk_bound_dev_if);
 219
 220                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 221                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 222                                              &ipv6_hdr(skb)->daddr))
 223                                 continue;
 224 #endif
 225                 } else {
 226                         continue;
 227                 }
 228
 229                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif &&
 230                     sk->sk_bound_dev_if != sdif)
 231                         continue;
 232
 233                 sock_hold(sk);
 234                 goto exit;
 235         }
 236
 237         sk = NULL;
 238 exit:
 239         read_unlock_bh(&ping_table.lock);
 240
 241         return sk;
 242 }
 243
 244 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 245                                           kgid_t *high)
 246 {
 247         kgid_t *data = net->ipv4.ping_group_range.range;
 248         unsigned int seq;
 249
 250         do {
 251                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 252
 253                 *low = data[0];
 254                 *high = data[1];
 255         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 256 }
 257
 258
 259 int ping_init_sock(struct sock *sk)
 260 {
 261         struct net *net = sock_net(sk);
 262         kgid_t group = current_egid();
 263         struct group_info *group_info;
 264         int i;
 265         kgid_t low, high;
 266         int ret = 0;
 267
 268         if (sk->sk_family == AF_INET6)
 269                 sk->sk_ipv6only = 1;
 270
 271         inet_get_ping_group_range_net(net, &low, &high);
 272         if (gid_lte(low, group) && gid_lte(group, high))
 273                 return 0;
 274
 275         group_info = get_current_groups();
 276         for (i = 0; i < group_info->ngroups; i++) {
 277                 kgid_t gid = group_info->gid[i];
 278
 279                 if (gid_lte(low, gid) && gid_lte(gid, high))
 280                         goto out_release_group;
 281         }
 282
 283         ret = -EACCES;
 284
 285 out_release_group:
 286         put_group_info(group_info);
 287         return ret;
 288 }
 289 EXPORT_SYMBOL_GPL(ping_init_sock);
 290
 291 void ping_close(struct sock *sk, long timeout)
 292 {
 293         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 294                  inet_sk(sk), inet_sk(sk)->inet_num);
 295         pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
 296
 297         sk_common_release(sk);
 298 }
 299 EXPORT_SYMBOL_GPL(ping_close);
 300
 301 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 302 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 303                                 struct sockaddr *uaddr, int addr_len)
 304 {
 305         struct net *net = sock_net(sk);
 306         if (sk->sk_family == AF_INET) {
 307                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 308                 u32 tb_id = RT_TABLE_LOCAL;
 309                 int chk_addr_ret;
 310
 311                 if (addr_len < sizeof(*addr))
 312                         return -EINVAL;
 313
 314                 if (addr->sin_family != AF_INET &&
 315                     !(addr->sin_family == AF_UNSPEC &&
 316                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 317                         return -EAFNOSUPPORT;
 318
 319                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 320                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 321
 322                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 323                         return 0;
 324
 325                 tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ? : tb_id;
 326                 chk_addr_ret = inet_addr_type_table(net, addr->sin_addr.s_addr, tb_id);
 327
 328                 if (chk_addr_ret == RTN_MULTICAST ||
 329                     chk_addr_ret == RTN_BROADCAST ||
 330                     (chk_addr_ret != RTN_LOCAL &&
 331                      !inet_can_nonlocal_bind(net, isk)))
 332                         return -EADDRNOTAVAIL;
 333
 334 #if IS_ENABLED(CONFIG_IPV6)
 335         } else if (sk->sk_family == AF_INET6) {
 336                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 337                 int addr_type, scoped, has_addr;
 338                 struct net_device *dev = NULL;
 339
 340                 if (addr_len < sizeof(*addr))
 341                         return -EINVAL;
 342
 343                 if (addr->sin6_family != AF_INET6)
 344                         return -EAFNOSUPPORT;
 345
 346                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 347                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 348
 349                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 350                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 351                 if ((addr_type != IPV6_ADDR_ANY &&
 352                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 353                     (scoped && !addr->sin6_scope_id))
 354                         return -EINVAL;
 355
 356                 rcu_read_lock();
 357                 if (addr->sin6_scope_id) {
 358                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 359                         if (!dev) {
 360                                 rcu_read_unlock();
 361                                 return -ENODEV;
 362                         }
 363                 }
 364
 365                 if (!dev && sk->sk_bound_dev_if) {
 366                         dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
 367                         if (!dev) {
 368                                 rcu_read_unlock();
 369                                 return -ENODEV;
 370                         }
 371                 }
 372                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 373                                                     scoped);
 374                 rcu_read_unlock();
 375
 376                 if (!(ipv6_can_nonlocal_bind(net, isk) || has_addr ||
 377                       addr_type == IPV6_ADDR_ANY))
 378                         return -EADDRNOTAVAIL;
 379
 380                 if (scoped)
 381                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 382 #endif
 383         } else {
 384                 return -EAFNOSUPPORT;
 385         }
 386         return 0;
 387 }
 388
 389 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 390 {
 391         if (saddr->sa_family == AF_INET) {
 392                 struct inet_sock *isk = inet_sk(sk);
 393                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 394                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 395 #if IS_ENABLED(CONFIG_IPV6)
 396         } else if (saddr->sa_family == AF_INET6) {
 397                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 398                 struct ipv6_pinfo *np = inet6_sk(sk);
 399                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 400 #endif
 401         }
 402 }
 403
 404 /*
 405  * We need our own bind because there are no privileged id's == local ports.
 406  * Moreover, we don't allow binding to multi- and broadcast addresses.
 407  */
 408
 409 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 410 {
 411         struct inet_sock *isk = inet_sk(sk);
 412         unsigned short snum;
 413         int err;
 414         int dif = sk->sk_bound_dev_if;
 415
 416         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 417         if (err)
 418                 return err;
 419
 420         lock_sock(sk);
 421
 422         err = -EINVAL;
 423         if (isk->inet_num != 0)
 424                 goto out;
 425
 426         err = -EADDRINUSE;
 427         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 428         if (ping_get_port(sk, snum) != 0) {
 429                 /* Restore possibly modified sk->sk_bound_dev_if by ping_check_bind_addr(). */
 430                 sk->sk_bound_dev_if = dif;
 431                 goto out;
 432         }
 433         ping_set_saddr(sk, uaddr);
 434
 435         pr_debug("after bind(): num = %hu, dif = %d\n",
 436                  isk->inet_num,
 437                  sk->sk_bound_dev_if);
 438
 439         err = 0;
 440         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 441                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 442 #if IS_ENABLED(CONFIG_IPV6)
 443         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 444                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 445 #endif
 446
 447         if (snum)
 448                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 449         isk->inet_sport = htons(isk->inet_num);
 450         isk->inet_daddr = 0;
 451         isk->inet_dport = 0;
 452
 453 #if IS_ENABLED(CONFIG_IPV6)
 454         if (sk->sk_family == AF_INET6)
 455                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 456 #endif
 457
 458         sk_dst_reset(sk);
 459 out:
 460         release_sock(sk);
 461         pr_debug("ping_v4_bind -> %d\n", err);
 462         return err;
 463 }
 464 EXPORT_SYMBOL_GPL(ping_bind);
 465
 466 /*
 467  * Is this a supported type of ICMP message?
 468  */
 469
 470 static inline int ping_supported(int family, int type, int code)
 471 {
 472         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 473                (family == AF_INET && type == ICMP_EXT_ECHO && code == 0) ||
 474                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0) ||
 475                (family == AF_INET6 && type == ICMPV6_EXT_ECHO_REQUEST && code == 0);
 476 }
 477
 478 /*
 479  * This routine is called by the ICMP module when it gets some
 480  * sort of error condition.
 481  */
 482
 483 void ping_err(struct sk_buff *skb, int offset, u32 info)
 484 {
 485         int family;
 486         struct icmphdr *icmph;
 487         struct inet_sock *inet_sock;
 488         int type;
 489         int code;
 490         struct net *net = dev_net(skb->dev);
 491         struct sock *sk;
 492         int harderr;
 493         int err;
 494
 495         if (skb->protocol == htons(ETH_P_IP)) {
 496                 family = AF_INET;
 497                 type = icmp_hdr(skb)->type;
 498                 code = icmp_hdr(skb)->code;
 499                 icmph = (struct icmphdr *)(skb->data + offset);
 500         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 501                 family = AF_INET6;
 502                 type = icmp6_hdr(skb)->icmp6_type;
 503                 code = icmp6_hdr(skb)->icmp6_code;
 504                 icmph = (struct icmphdr *) (skb->data + offset);
 505         } else {
 506                 BUG();
 507         }
 508
 509         /* We assume the packet has already been checked by icmp_unreach */
 510
 511         if (!ping_supported(family, icmph->type, icmph->code))
 512                 return;
 513
 514         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 515                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 516                  ntohs(icmph->un.echo.sequence));
 517
 518         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 519         if (!sk) {
 520                 pr_debug("no socket, dropping\n");
 521                 return; /* No socket for error */
 522         }
 523         pr_debug("err on socket %p\n", sk);
 524
 525         err = 0;
 526         harderr = 0;
 527         inet_sock = inet_sk(sk);
 528
 529         if (skb->protocol == htons(ETH_P_IP)) {
 530                 switch (type) {
 531                 default:
 532                 case ICMP_TIME_EXCEEDED:
 533                         err = EHOSTUNREACH;
 534                         break;
 535                 case ICMP_SOURCE_QUENCH:
 536                         /* This is not a real error but ping wants to see it.
 537                          * Report it with some fake errno.
 538                          */
 539                         err = EREMOTEIO;
 540                         break;
 541                 case ICMP_PARAMETERPROB:
 542                         err = EPROTO;
 543                         harderr = 1;
 544                         break;
 545                 case ICMP_DEST_UNREACH:
 546                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 547                                 ipv4_sk_update_pmtu(skb, sk, info);
 548                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 549                                         err = EMSGSIZE;
 550                                         harderr = 1;
 551                                         break;
 552                                 }
 553                                 goto out;
 554                         }
 555                         err = EHOSTUNREACH;
 556                         if (code <= NR_ICMP_UNREACH) {
 557                                 harderr = icmp_err_convert[code].fatal;
 558                                 err = icmp_err_convert[code].errno;
 559                         }
 560                         break;
 561                 case ICMP_REDIRECT:
 562                         /* See ICMP_SOURCE_QUENCH */
 563                         ipv4_sk_redirect(skb, sk);
 564                         err = EREMOTEIO;
 565                         break;
 566                 }
 567 #if IS_ENABLED(CONFIG_IPV6)
 568         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 569                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 570 #endif
 571         }
 572
 573         /*
 574          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 575          *      4.1.3.3.
 576          */
 577         if ((family == AF_INET && !inet_sock->recverr) ||
 578             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 579                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 580                         goto out;
 581         } else {
 582                 if (family == AF_INET) {
 583                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 584                                       info, (u8 *)icmph);
 585 #if IS_ENABLED(CONFIG_IPV6)
 586                 } else if (family == AF_INET6) {
 587                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 588                                                    info, (u8 *)icmph);
 589 #endif
 590                 }
 591         }
 592         sk->sk_err = err;
 593         sk_error_report(sk);
 594 out:
 595         sock_put(sk);
 596 }
 597 EXPORT_SYMBOL_GPL(ping_err);
 598
 599 /*
 600  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 601  *      starting from the payload.
 602  */
 603
 604 int ping_getfrag(void *from, char *to,
 605                  int offset, int fraglen, int odd, struct sk_buff *skb)
 606 {
 607         struct pingfakehdr *pfh = from;
 608
 609         if (offset == 0) {
 610                 fraglen -= sizeof(struct icmphdr);
 611                 if (fraglen < 0)
 612                         BUG();
 613                 if (!csum_and_copy_from_iter_full(to + sizeof(struct icmphdr),
 614                             fraglen, &pfh->wcheck,
 615                             &pfh->msg->msg_iter))
 616                         return -EFAULT;
 617         } else if (offset < sizeof(struct icmphdr)) {
 618                         BUG();
 619         } else {
 620                 if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
 621                                             &pfh->msg->msg_iter))
 622                         return -EFAULT;
 623         }
 624
 625 #if IS_ENABLED(CONFIG_IPV6)
 626         /* For IPv6, checksum each skb as we go along, as expected by
 627          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 628          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 629          */
 630         if (pfh->family == AF_INET6) {
 631                 skb->csum = pfh->wcheck;
 632                 skb->ip_summed = CHECKSUM_NONE;
 633                 pfh->wcheck = 0;
 634         }
 635 #endif
 636
 637         return 0;
 638 }
 639 EXPORT_SYMBOL_GPL(ping_getfrag);
 640
 641 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 642                                        struct flowi4 *fl4)
 643 {
 644         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 645
 646         if (!skb)
 647                 return 0;
 648         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 649                 sizeof(struct icmphdr), pfh->wcheck);
 650         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 651         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 652         skb->ip_summed = CHECKSUM_NONE;
 653         return ip_push_pending_frames(sk, fl4);
 654 }
 655
 656 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 657                         void *user_icmph, size_t icmph_len)
 658 {
 659         u8 type, code;
 660
 661         if (len > 0xFFFF)
 662                 return -EMSGSIZE;
 663
 664         /* Must have at least a full ICMP header. */
 665         if (len < icmph_len)
 666                 return -EINVAL;
 667
 668         /*
 669          *      Check the flags.
 670          */
 671
 672         /* Mirror BSD error message compatibility */
 673         if (msg->msg_flags & MSG_OOB)
 674                 return -EOPNOTSUPP;
 675
 676         /*
 677          *      Fetch the ICMP header provided by the userland.
 678          *      iovec is modified! The ICMP header is consumed.
 679          */
 680         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 681                 return -EFAULT;
 682
 683         if (family == AF_INET) {
 684                 type = ((struct icmphdr *) user_icmph)->type;
 685                 code = ((struct icmphdr *) user_icmph)->code;
 686 #if IS_ENABLED(CONFIG_IPV6)
 687         } else if (family == AF_INET6) {
 688                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 689                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 690 #endif
 691         } else {
 692                 BUG();
 693         }
 694
 695         if (!ping_supported(family, type, code))
 696                 return -EINVAL;
 697
 698         return 0;
 699 }
 700 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 701
 702 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 703 {
 704         struct net *net = sock_net(sk);
 705         struct flowi4 fl4;
 706         struct inet_sock *inet = inet_sk(sk);
 707         struct ipcm_cookie ipc;
 708         struct icmphdr user_icmph;
 709         struct pingfakehdr pfh;
 710         struct rtable *rt = NULL;
 711         struct ip_options_data opt_copy;
 712         int free = 0;
 713         __be32 saddr, daddr, faddr;
 714         u8  tos;
 715         int err;
 716
 717         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 718
 719         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 720                                   sizeof(user_icmph));
 721         if (err)
 722                 return err;
 723
 724         /*
 725          *      Get and verify the address.
 726          */
 727
 728         if (msg->msg_name) {
 729                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 730                 if (msg->msg_namelen < sizeof(*usin))
 731                         return -EINVAL;
 732                 if (usin->sin_family != AF_INET)
 733                         return -EAFNOSUPPORT;
 734                 daddr = usin->sin_addr.s_addr;
 735                 /* no remote port */
 736         } else {
 737                 if (sk->sk_state != TCP_ESTABLISHED)
 738                         return -EDESTADDRREQ;
 739                 daddr = inet->inet_daddr;
 740                 /* no remote port */
 741         }
 742
 743         ipcm_init_sk(&ipc, inet);
 744
 745         if (msg->msg_controllen) {
 746                 err = ip_cmsg_send(sk, msg, &ipc, false);
 747                 if (unlikely(err)) {
 748                         kfree(ipc.opt);
 749                         return err;
 750                 }
 751                 if (ipc.opt)
 752                         free = 1;
 753         }
 754         if (!ipc.opt) {
 755                 struct ip_options_rcu *inet_opt;
 756
 757                 rcu_read_lock();
 758                 inet_opt = rcu_dereference(inet->inet_opt);
 759                 if (inet_opt) {
 760                         memcpy(&opt_copy, inet_opt,
 761                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 762                         ipc.opt = &opt_copy.opt;
 763                 }
 764                 rcu_read_unlock();
 765         }
 766
 767         saddr = ipc.addr;
 768         ipc.addr = faddr = daddr;
 769
 770         if (ipc.opt && ipc.opt->opt.srr) {
 771                 if (!daddr) {
 772                         err = -EINVAL;
 773                         goto out_free;
 774                 }
 775                 faddr = ipc.opt->opt.faddr;
 776         }
 777         tos = get_rttos(&ipc, inet);
 778         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 779             (msg->msg_flags & MSG_DONTROUTE) ||
 780             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 781                 tos |= RTO_ONLINK;
 782         }
 783
 784         if (ipv4_is_multicast(daddr)) {
 785                 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
 786                         ipc.oif = inet->mc_index;
 787                 if (!saddr)
 788                         saddr = inet->mc_addr;
 789         } else if (!ipc.oif)
 790                 ipc.oif = inet->uc_index;
 791
 792         flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos,
 793                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 794                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
 795                            sk->sk_uid);
 796
 797         fl4.fl4_icmp_type = user_icmph.type;
 798         fl4.fl4_icmp_code = user_icmph.code;
 799
 800         security_sk_classify_flow(sk, flowi4_to_flowi_common(&fl4));
 801         rt = ip_route_output_flow(net, &fl4, sk);
 802         if (IS_ERR(rt)) {
 803                 err = PTR_ERR(rt);
 804                 rt = NULL;
 805                 if (err == -ENETUNREACH)
 806                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 807                 goto out;
 808         }
 809
 810         err = -EACCES;
 811         if ((rt->rt_flags & RTCF_BROADCAST) &&
 812             !sock_flag(sk, SOCK_BROADCAST))
 813                 goto out;
 814
 815         if (msg->msg_flags & MSG_CONFIRM)
 816                 goto do_confirm;
 817 back_from_confirm:
 818
 819         if (!ipc.addr)
 820                 ipc.addr = fl4.daddr;
 821
 822         lock_sock(sk);
 823
 824         pfh.icmph.type = user_icmph.type; /* already checked */
 825         pfh.icmph.code = user_icmph.code; /* ditto */
 826         pfh.icmph.checksum = 0;
 827         pfh.icmph.un.echo.id = inet->inet_sport;
 828         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 829         pfh.msg = msg;
 830         pfh.wcheck = 0;
 831         pfh.family = AF_INET;
 832
 833         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 834                         0, &ipc, &rt, msg->msg_flags);
 835         if (err)
 836                 ip_flush_pending_frames(sk);
 837         else
 838                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 839         release_sock(sk);
 840
 841 out:
 842         ip_rt_put(rt);
 843 out_free:
 844         if (free)
 845                 kfree(ipc.opt);
 846         if (!err) {
 847                 icmp_out_count(sock_net(sk), user_icmph.type);
 848                 return len;
 849         }
 850         return err;
 851
 852 do_confirm:
 853         if (msg->msg_flags & MSG_PROBE)
 854                 dst_confirm_neigh(&rt->dst, &fl4.daddr);
 855         if (!(msg->msg_flags & MSG_PROBE) || len)
 856                 goto back_from_confirm;
 857         err = 0;
 858         goto out;
 859 }
 860
 861 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
 862                  int *addr_len)
 863 {
 864         struct inet_sock *isk = inet_sk(sk);
 865         int family = sk->sk_family;
 866         struct sk_buff *skb;
 867         int copied, err;
 868
 869         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 870
 871         err = -EOPNOTSUPP;
 872         if (flags & MSG_OOB)
 873                 goto out;
 874
 875         if (flags & MSG_ERRQUEUE)
 876                 return inet_recv_error(sk, msg, len, addr_len);
 877
 878         skb = skb_recv_datagram(sk, flags, &err);
 879         if (!skb)
 880                 goto out;
 881
 882         copied = skb->len;
 883         if (copied > len) {
 884                 msg->msg_flags |= MSG_TRUNC;
 885                 copied = len;
 886         }
 887
 888         /* Don't bother checking the checksum */
 889         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 890         if (err)
 891                 goto done;
 892
 893         sock_recv_timestamp(msg, sk, skb);
 894
 895         /* Copy the address and add cmsg data. */
 896         if (family == AF_INET) {
 897                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 898
 899                 if (sin) {
 900                         sin->sin_family = AF_INET;
 901                         sin->sin_port = 0 /* skb->h.uh->source */;
 902                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 903                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 904                         *addr_len = sizeof(*sin);
 905                 }
 906
 907                 if (isk->cmsg_flags)
 908                         ip_cmsg_recv(msg, skb);
 909
 910 #if IS_ENABLED(CONFIG_IPV6)
 911         } else if (family == AF_INET6) {
 912                 struct ipv6_pinfo *np = inet6_sk(sk);
 913                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 914                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 915
 916                 if (sin6) {
 917                         sin6->sin6_family = AF_INET6;
 918                         sin6->sin6_port = 0;
 919                         sin6->sin6_addr = ip6->saddr;
 920                         sin6->sin6_flowinfo = 0;
 921                         if (np->sndflow)
 922                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 923                         sin6->sin6_scope_id =
 924                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 925                                                     inet6_iif(skb));
 926                         *addr_len = sizeof(*sin6);
 927                 }
 928
 929                 if (inet6_sk(sk)->rxopt.all)
 930                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 931                 if (skb->protocol == htons(ETH_P_IPV6) &&
 932                     inet6_sk(sk)->rxopt.all)
 933                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 934                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 935                         ip_cmsg_recv(msg, skb);
 936 #endif
 937         } else {
 938                 BUG();
 939         }
 940
 941         err = copied;
 942
 943 done:
 944         skb_free_datagram(sk, skb);
 945 out:
 946         pr_debug("ping_recvmsg -> %d\n", err);
 947         return err;
 948 }
 949 EXPORT_SYMBOL_GPL(ping_recvmsg);
 950
 951 static enum skb_drop_reason __ping_queue_rcv_skb(struct sock *sk,
 952                                                  struct sk_buff *skb)
 953 {
 954         enum skb_drop_reason reason;
 955
 956         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 957                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 958         if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
 959                 kfree_skb_reason(skb, reason);
 960                 pr_debug("ping_queue_rcv_skb -> failed\n");
 961                 return reason;
 962         }
 963         return SKB_NOT_DROPPED_YET;
 964 }
 965
 966 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 967 {
 968         return __ping_queue_rcv_skb(sk, skb) ? -1 : 0;
 969 }
 970 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 971
 972
 973 /*
 974  *      All we need to do is get the socket.
 975  */
 976
 977 enum skb_drop_reason ping_rcv(struct sk_buff *skb)
 978 {
 979         enum skb_drop_reason reason = SKB_DROP_REASON_NO_SOCKET;
 980         struct sock *sk;
 981         struct net *net = dev_net(skb->dev);
 982         struct icmphdr *icmph = icmp_hdr(skb);
 983
 984         /* We assume the packet has already been checked by icmp_rcv */
 985
 986         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 987                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 988
 989         /* Push ICMP header back */
 990         skb_push(skb, skb->data - (u8 *)icmph);
 991
 992         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 993         if (sk) {
 994                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 995
 996                 pr_debug("rcv on socket %p\n", sk);
 997                 if (skb2)
 998                         reason = __ping_queue_rcv_skb(sk, skb2);
 999                 else
1000                         reason = SKB_DROP_REASON_NOMEM;
1001                 sock_put(sk);
1002         }
1003
1004         if (reason)
1005                 pr_debug("no socket, dropping\n");
1006
1007         return reason;
1008 }
1009 EXPORT_SYMBOL_GPL(ping_rcv);
1010
1011 struct proto ping_prot = {
1012         .name =         "PING",
1013         .owner =        THIS_MODULE,
1014         .init =         ping_init_sock,
1015         .close =        ping_close,
1016         .connect =      ip4_datagram_connect,
1017         .disconnect =   __udp_disconnect,
1018         .setsockopt =   ip_setsockopt,
1019         .getsockopt =   ip_getsockopt,
1020         .sendmsg =      ping_v4_sendmsg,
1021         .recvmsg =      ping_recvmsg,
1022         .bind =         ping_bind,
1023         .backlog_rcv =  ping_queue_rcv_skb,
1024         .release_cb =   ip4_datagram_release_cb,
1025         .hash =         ping_hash,
1026         .unhash =       ping_unhash,
1027         .get_port =     ping_get_port,
1028         .put_port =     ping_unhash,
1029         .obj_size =     sizeof(struct inet_sock),
1030 };
1031 EXPORT_SYMBOL(ping_prot);
1032
1033 #ifdef CONFIG_PROC_FS
1034
1035 static struct sock *ping_get_first(struct seq_file *seq, int start)
1036 {
1037         struct sock *sk;
1038         struct ping_iter_state *state = seq->private;
1039         struct net *net = seq_file_net(seq);
1040
1041         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1042              ++state->bucket) {
1043                 struct hlist_nulls_node *node;
1044                 struct hlist_nulls_head *hslot;
1045
1046                 hslot = &ping_table.hash[state->bucket];
1047
1048                 if (hlist_nulls_empty(hslot))
1049                         continue;
1050
1051                 sk_nulls_for_each(sk, node, hslot) {
1052                         if (net_eq(sock_net(sk), net) &&
1053                             sk->sk_family == state->family)
1054                                 goto found;
1055                 }
1056         }
1057         sk = NULL;
1058 found:
1059         return sk;
1060 }
1061
1062 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1063 {
1064         struct ping_iter_state *state = seq->private;
1065         struct net *net = seq_file_net(seq);
1066
1067         do {
1068                 sk = sk_nulls_next(sk);
1069         } while (sk && (!net_eq(sock_net(sk), net)));
1070
1071         if (!sk)
1072                 return ping_get_first(seq, state->bucket + 1);
1073         return sk;
1074 }
1075
1076 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1077 {
1078         struct sock *sk = ping_get_first(seq, 0);
1079
1080         if (sk)
1081                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1082                         --pos;
1083         return pos ? NULL : sk;
1084 }
1085
1086 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1087         __acquires(ping_table.lock)
1088 {
1089         struct ping_iter_state *state = seq->private;
1090         state->bucket = 0;
1091         state->family = family;
1092
1093         read_lock_bh(&ping_table.lock);
1094
1095         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1096 }
1097 EXPORT_SYMBOL_GPL(ping_seq_start);
1098
1099 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1100 {
1101         return ping_seq_start(seq, pos, AF_INET);
1102 }
1103
1104 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1105 {
1106         struct sock *sk;
1107
1108         if (v == SEQ_START_TOKEN)
1109                 sk = ping_get_idx(seq, 0);
1110         else
1111                 sk = ping_get_next(seq, v);
1112
1113         ++*pos;
1114         return sk;
1115 }
1116 EXPORT_SYMBOL_GPL(ping_seq_next);
1117
1118 void ping_seq_stop(struct seq_file *seq, void *v)
1119         __releases(ping_table.lock)
1120 {
1121         read_unlock_bh(&ping_table.lock);
1122 }
1123 EXPORT_SYMBOL_GPL(ping_seq_stop);
1124
1125 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1126                 int bucket)
1127 {
1128         struct inet_sock *inet = inet_sk(sp);
1129         __be32 dest = inet->inet_daddr;
1130         __be32 src = inet->inet_rcv_saddr;
1131         __u16 destp = ntohs(inet->inet_dport);
1132         __u16 srcp = ntohs(inet->inet_sport);
1133
1134         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1135                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
1136                 bucket, src, srcp, dest, destp, sp->sk_state,
1137                 sk_wmem_alloc_get(sp),
1138                 sk_rmem_alloc_get(sp),
1139                 0, 0L, 0,
1140                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1141                 0, sock_i_ino(sp),
1142                 refcount_read(&sp->sk_refcnt), sp,
1143                 atomic_read(&sp->sk_drops));
1144 }
1145
1146 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1147 {
1148         seq_setwidth(seq, 127);
1149         if (v == SEQ_START_TOKEN)
1150                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1151                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1152                            "inode ref pointer drops");
1153         else {
1154                 struct ping_iter_state *state = seq->private;
1155
1156                 ping_v4_format_sock(v, seq, state->bucket);
1157         }
1158         seq_pad(seq, '\n');
1159         return 0;
1160 }
1161
1162 static const struct seq_operations ping_v4_seq_ops = {
1163         .start          = ping_v4_seq_start,
1164         .show           = ping_v4_seq_show,
1165         .next           = ping_seq_next,
1166         .stop           = ping_seq_stop,
1167 };
1168
1169 static int __net_init ping_v4_proc_init_net(struct net *net)
1170 {
1171         if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
1172                         sizeof(struct ping_iter_state)))
1173                 return -ENOMEM;
1174         return 0;
1175 }
1176
1177 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1178 {
1179         remove_proc_entry("icmp", net->proc_net);
1180 }
1181
1182 static struct pernet_operations ping_v4_net_ops = {
1183         .init = ping_v4_proc_init_net,
1184         .exit = ping_v4_proc_exit_net,
1185 };
1186
1187 int __init ping_proc_init(void)
1188 {
1189         return register_pernet_subsys(&ping_v4_net_ops);
1190 }
1191
1192 void ping_proc_exit(void)
1193 {
1194         unregister_pernet_subsys(&ping_v4_net_ops);
1195 }
1196
1197 #endif
1198
1199 void __init ping_init(void)
1200 {
1201         int i;
1202
1203         for (i = 0; i < PING_HTABLE_SIZE; i++)
1204                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1205         rwlock_init(&ping_table.lock);
1206 }