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