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 <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
  52 struct ping_table {
  53         struct hlist_head       hash[PING_HTABLE_SIZE];
  54         spinlock_t              lock;
  55 };
  56
  57 static struct ping_table ping_table;
  58 struct pingv6_ops pingv6_ops;
  59 EXPORT_SYMBOL_GPL(pingv6_ops);
  60
  61 static u16 ping_port_rover;
  62
  63 static 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 }
  70 EXPORT_SYMBOL_GPL(ping_hash);
  71
  72 static 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
  78 int 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;
 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                 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
 137 fail:
 138         spin_unlock(&ping_table.lock);
 139         return -EADDRINUSE;
 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         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 }
 164 EXPORT_SYMBOL_GPL(ping_unhash);
 165
 166 /* Called under rcu_read_lock() */
 167 static 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;
 232 exit:
 233
 234         return sk;
 235 }
 236
 237 static 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
 252 int 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
 278 out_release_group:
 279         put_group_info(group_info);
 280         return ret;
 281 }
 282 EXPORT_SYMBOL_GPL(ping_init_sock);
 283
 284 void 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 }
 292 EXPORT_SYMBOL_GPL(ping_close);
 293
 294 static 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. */
 308 static 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
 395 static 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
 415 int 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);
 465 out:
 466         release_sock(sk);
 467         pr_debug("ping_v4_bind -> %d\n", err);
 468         return err;
 469 }
 470 EXPORT_SYMBOL_GPL(ping_bind);
 471
 472 /*
 473  * Is this a supported type of ICMP message?
 474  */
 475
 476 static 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
 489 void 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);
 600 out:
 601         return;
 602 }
 603 EXPORT_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
 610 int 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 }
 633 EXPORT_SYMBOL_GPL(ping_getfrag);
 634
 635 static 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
 650 int 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 }
 694 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 695
 696 static 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;
 806 back_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
 831 out:
 832         ip_rt_put(rt);
 833 out_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
 842 do_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
 851 int 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
 933 done:
 934         skb_free_datagram(sk, skb);
 935 out:
 936         pr_debug("ping_recvmsg -> %d\n", err);
 937         return err;
 938 }
 939 EXPORT_SYMBOL_GPL(ping_recvmsg);
 940
 941 static 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                 kfree_skb_reason(skb, reason);
 950                 pr_debug("ping_queue_rcv_skb -> failed\n");
 951                 return reason;
 952         }
 953         return SKB_NOT_DROPPED_YET;
 954 }
 955
 956 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 957 {
 958         return __ping_queue_rcv_skb(sk, skb) ? -1 : 0;
 959 }
 960 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 961
 962
 963 /*
 964  *      All we need to do is get the socket.
 965  */
 966
 967 enum 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 }
 998 EXPORT_SYMBOL_GPL(ping_rcv);
 999
1000 struct 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 };
1021 EXPORT_SYMBOL(ping_prot);
1022
1023 #ifdef CONFIG_PROC_FS
1024
1025 static 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;
1047 found:
1048         return sk;
1049 }
1050
1051 static 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
1065 static 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
1075 void *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 }
1086 EXPORT_SYMBOL_GPL(ping_seq_start);
1087
1088 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1089 {
1090         return ping_seq_start(seq, pos, AF_INET);
1091 }
1092
1093 void *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 }
1105 EXPORT_SYMBOL_GPL(ping_seq_next);
1106
1107 void ping_seq_stop(struct seq_file *seq, void *v)
1108         __releases(ping_table.lock)
1109 {
1110         spin_unlock(&ping_table.lock);
1111 }
1112 EXPORT_SYMBOL_GPL(ping_seq_stop);
1113
1114 static 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
1135 static 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
1151 static 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
1158 static 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
1166 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1167 {
1168         remove_proc_entry("icmp", net->proc_net);
1169 }
1170
1171 static struct pernet_operations ping_v4_net_ops = {
1172         .init = ping_v4_proc_init_net,
1173         .exit = ping_v4_proc_exit_net,
1174 };
1175
1176 int __init ping_proc_init(void)
1177 {
1178         return register_pernet_subsys(&ping_v4_net_ops);
1179 }
1180
1181 void ping_proc_exit(void)
1182 {
1183         unregister_pernet_subsys(&ping_v4_net_ops);
1184 }
1185
1186 #endif
1187
1188 void __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 }