net/ipv4/ping.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              "Ping" sockets
   7  *
   8  *              This program is free software; you can redistribute it and/or
   9  *              modify it under the terms of the GNU General Public License
  10  *              as published by the Free Software Foundation; either version
  11  *              2 of the License, or (at your option) any later version.
  12  *
  13  * Based on ipv4/udp.c code.
  14  *
  15  * Authors:     Vasiliy Kulikov / Openwall (for Linux 2.6),
  16  *              Pavel Kankovsky (for Linux 2.4.32)
  17  *
  18  * Pavel gave all rights to bugs to Vasiliy,
  19  * none of the bugs are Pavel's now.
  20  *
  21  */
  22
  23 #include <linux/uaccess.h>
  24 #include <linux/types.h>
  25 #include <linux/fcntl.h>
  26 #include <linux/socket.h>
  27 #include <linux/sockios.h>
  28 #include <linux/in.h>
  29 #include <linux/errno.h>
  30 #include <linux/timer.h>
  31 #include <linux/mm.h>
  32 #include <linux/inet.h>
  33 #include <linux/netdevice.h>
  34 #include <net/snmp.h>
  35 #include <net/ip.h>
  36 #include <net/icmp.h>
  37 #include <net/protocol.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/proc_fs.h>
  40 #include <linux/export.h>
  41 #include <net/sock.h>
  42 #include <net/ping.h>
  43 #include <net/udp.h>
  44 #include <net/route.h>
  45 #include <net/inet_common.h>
  46 #include <net/checksum.h>
  47
  48 #if IS_ENABLED(CONFIG_IPV6)
  49 #include <linux/in6.h>
  50 #include <linux/icmpv6.h>
  51 #include <net/addrconf.h>
  52 #include <net/ipv6.h>
  53 #include <net/transp_v6.h>
  54 #endif
  55
  56 struct ping_table {
  57         struct hlist_nulls_head hash[PING_HTABLE_SIZE];
  58         rwlock_t                lock;
  59 };
  60
  61 static struct ping_table ping_table;
  62 struct pingv6_ops pingv6_ops;
  63 EXPORT_SYMBOL_GPL(pingv6_ops);
  64
  65 static u16 ping_port_rover;
  66
  67 static inline u32 ping_hashfn(const struct net *net, u32 num, u32 mask)
  68 {
  69         u32 res = (num + net_hash_mix(net)) & mask;
  70
  71         pr_debug("hash(%u) = %u\n", num, res);
  72         return res;
  73 }
  74 EXPORT_SYMBOL_GPL(ping_hash);
  75
  76 static inline struct hlist_nulls_head *ping_hashslot(struct ping_table *table,
  77                                              struct net *net, unsigned int num)
  78 {
  79         return &table->hash[ping_hashfn(net, num, PING_HTABLE_MASK)];
  80 }
  81
  82 int ping_get_port(struct sock *sk, unsigned short ident)
  83 {
  84         struct hlist_nulls_node *node;
  85         struct hlist_nulls_head *hlist;
  86         struct inet_sock *isk, *isk2;
  87         struct sock *sk2 = NULL;
  88
  89         isk = inet_sk(sk);
  90         write_lock_bh(&ping_table.lock);
  91         if (ident == 0) {
  92                 u32 i;
  93                 u16 result = ping_port_rover + 1;
  94
  95                 for (i = 0; i < (1L << 16); i++, result++) {
  96                         if (!result)
  97                                 result++; /* avoid zero */
  98                         hlist = ping_hashslot(&ping_table, sock_net(sk),
  99                                             result);
 100                         ping_portaddr_for_each_entry(sk2, node, hlist) {
 101                                 isk2 = inet_sk(sk2);
 102
 103                                 if (isk2->inet_num == result)
 104                                         goto next_port;
 105                         }
 106
 107                         /* found */
 108                         ping_port_rover = ident = result;
 109                         break;
 110 next_port:
 111                         ;
 112                 }
 113                 if (i >= (1L << 16))
 114                         goto fail;
 115         } else {
 116                 hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
 117                 ping_portaddr_for_each_entry(sk2, node, hlist) {
 118                         isk2 = inet_sk(sk2);
 119
 120                         /* BUG? Why is this reuse and not reuseaddr? ping.c
 121                          * doesn't turn off SO_REUSEADDR, and it doesn't expect
 122                          * that other ping processes can steal its packets.
 123                          */
 124                         if ((isk2->inet_num == ident) &&
 125                             (sk2 != sk) &&
 126                             (!sk2->sk_reuse || !sk->sk_reuse))
 127                                 goto fail;
 128                 }
 129         }
 130
 131         pr_debug("found port/ident = %d\n", ident);
 132         isk->inet_num = ident;
 133         if (sk_unhashed(sk)) {
 134                 pr_debug("was not hashed\n");
 135                 sock_hold(sk);
 136                 hlist_nulls_add_head(&sk->sk_nulls_node, hlist);
 137                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 138         }
 139         write_unlock_bh(&ping_table.lock);
 140         return 0;
 141
 142 fail:
 143         write_unlock_bh(&ping_table.lock);
 144         return 1;
 145 }
 146 EXPORT_SYMBOL_GPL(ping_get_port);
 147
 148 int ping_hash(struct sock *sk)
 149 {
 150         pr_debug("ping_hash(sk->port=%u)\n", inet_sk(sk)->inet_num);
 151         BUG(); /* "Please do not press this button again." */
 152
 153         return 0;
 154 }
 155
 156 void ping_unhash(struct sock *sk)
 157 {
 158         struct inet_sock *isk = inet_sk(sk);
 159
 160         pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
 161         write_lock_bh(&ping_table.lock);
 162         if (sk_hashed(sk)) {
 163                 hlist_nulls_del(&sk->sk_nulls_node);
 164                 sk_nulls_node_init(&sk->sk_nulls_node);
 165                 sock_put(sk);
 166                 isk->inet_num = 0;
 167                 isk->inet_sport = 0;
 168                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 169         }
 170         write_unlock_bh(&ping_table.lock);
 171 }
 172 EXPORT_SYMBOL_GPL(ping_unhash);
 173
 174 static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 175 {
 176         struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
 177         struct sock *sk = NULL;
 178         struct inet_sock *isk;
 179         struct hlist_nulls_node *hnode;
 180         int dif = skb->dev->ifindex;
 181
 182         if (skb->protocol == htons(ETH_P_IP)) {
 183                 pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
 184                          (int)ident, &ip_hdr(skb)->daddr, dif);
 185 #if IS_ENABLED(CONFIG_IPV6)
 186         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 187                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 188                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
 189 #endif
 190         }
 191
 192         read_lock_bh(&ping_table.lock);
 193
 194         ping_portaddr_for_each_entry(sk, hnode, hslot) {
 195                 isk = inet_sk(sk);
 196
 197                 pr_debug("iterate\n");
 198                 if (isk->inet_num != ident)
 199                         continue;
 200
 201                 if (skb->protocol == htons(ETH_P_IP) &&
 202                     sk->sk_family == AF_INET) {
 203                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 204                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
 205                                  sk->sk_bound_dev_if);
 206
 207                         if (isk->inet_rcv_saddr &&
 208                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 209                                 continue;
 210 #if IS_ENABLED(CONFIG_IPV6)
 211                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
 212                            sk->sk_family == AF_INET6) {
 213
 214                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 215                                  (int) isk->inet_num,
 216                                  &sk->sk_v6_rcv_saddr,
 217                                  sk->sk_bound_dev_if);
 218
 219                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 220                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 221                                              &ipv6_hdr(skb)->daddr))
 222                                 continue;
 223 #endif
 224                 } else {
 225                         continue;
 226                 }
 227
 228                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
 229                         continue;
 230
 231                 sock_hold(sk);
 232                 goto exit;
 233         }
 234
 235         sk = NULL;
 236 exit:
 237         read_unlock_bh(&ping_table.lock);
 238
 239         return sk;
 240 }
 241
 242 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 243                                           kgid_t *high)
 244 {
 245         kgid_t *data = net->ipv4.ping_group_range.range;
 246         unsigned int seq;
 247
 248         do {
 249                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 250
 251                 *low = data[0];
 252                 *high = data[1];
 253         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 254 }
 255
 256
 257 int ping_init_sock(struct sock *sk)
 258 {
 259         struct net *net = sock_net(sk);
 260         kgid_t group = current_egid();
 261         struct group_info *group_info;
 262         int i;
 263         kgid_t low, high;
 264         int ret = 0;
 265
 266         if (sk->sk_family == AF_INET6)
 267                 sk->sk_ipv6only = 1;
 268
 269         inet_get_ping_group_range_net(net, &low, &high);
 270         if (gid_lte(low, group) && gid_lte(group, high))
 271                 return 0;
 272
 273         group_info = get_current_groups();
 274         for (i = 0; i < group_info->ngroups; i++) {
 275                 kgid_t gid = group_info->gid[i];
 276
 277                 if (gid_lte(low, gid) && gid_lte(gid, high))
 278                         goto out_release_group;
 279         }
 280
 281         ret = -EACCES;
 282
 283 out_release_group:
 284         put_group_info(group_info);
 285         return ret;
 286 }
 287 EXPORT_SYMBOL_GPL(ping_init_sock);
 288
 289 void ping_close(struct sock *sk, long timeout)
 290 {
 291         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 292                  inet_sk(sk), inet_sk(sk)->inet_num);
 293         pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
 294
 295         sk_common_release(sk);
 296 }
 297 EXPORT_SYMBOL_GPL(ping_close);
 298
 299 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 300 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 301                                 struct sockaddr *uaddr, int addr_len) {
 302         struct net *net = sock_net(sk);
 303         if (sk->sk_family == AF_INET) {
 304                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 305                 int chk_addr_ret;
 306
 307                 if (addr_len < sizeof(*addr))
 308                         return -EINVAL;
 309
 310                 if (addr->sin_family != AF_INET &&
 311                     !(addr->sin_family == AF_UNSPEC &&
 312                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 313                         return -EAFNOSUPPORT;
 314
 315                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 316                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 317
 318                 chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
 319
 320                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 321                         chk_addr_ret = RTN_LOCAL;
 322
 323                 if ((!inet_can_nonlocal_bind(net, isk) &&
 324                      chk_addr_ret != RTN_LOCAL) ||
 325                     chk_addr_ret == RTN_MULTICAST ||
 326                     chk_addr_ret == RTN_BROADCAST)
 327                         return -EADDRNOTAVAIL;
 328
 329 #if IS_ENABLED(CONFIG_IPV6)
 330         } else if (sk->sk_family == AF_INET6) {
 331                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 332                 int addr_type, scoped, has_addr;
 333                 struct net_device *dev = NULL;
 334
 335                 if (addr_len < sizeof(*addr))
 336                         return -EINVAL;
 337
 338                 if (addr->sin6_family != AF_INET6)
 339                         return -EAFNOSUPPORT;
 340
 341                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 342                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 343
 344                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 345                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 346                 if ((addr_type != IPV6_ADDR_ANY &&
 347                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 348                     (scoped && !addr->sin6_scope_id))
 349                         return -EINVAL;
 350
 351                 rcu_read_lock();
 352                 if (addr->sin6_scope_id) {
 353                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 354                         if (!dev) {
 355                                 rcu_read_unlock();
 356                                 return -ENODEV;
 357                         }
 358                 }
 359                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 360                                                     scoped);
 361                 rcu_read_unlock();
 362
 363                 if (!(ipv6_can_nonlocal_bind(net, isk) || has_addr ||
 364                       addr_type == IPV6_ADDR_ANY))
 365                         return -EADDRNOTAVAIL;
 366
 367                 if (scoped)
 368                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 369 #endif
 370         } else {
 371                 return -EAFNOSUPPORT;
 372         }
 373         return 0;
 374 }
 375
 376 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 377 {
 378         if (saddr->sa_family == AF_INET) {
 379                 struct inet_sock *isk = inet_sk(sk);
 380                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 381                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 382 #if IS_ENABLED(CONFIG_IPV6)
 383         } else if (saddr->sa_family == AF_INET6) {
 384                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 385                 struct ipv6_pinfo *np = inet6_sk(sk);
 386                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 387 #endif
 388         }
 389 }
 390
 391 static void ping_clear_saddr(struct sock *sk, int dif)
 392 {
 393         sk->sk_bound_dev_if = dif;
 394         if (sk->sk_family == AF_INET) {
 395                 struct inet_sock *isk = inet_sk(sk);
 396                 isk->inet_rcv_saddr = isk->inet_saddr = 0;
 397 #if IS_ENABLED(CONFIG_IPV6)
 398         } else if (sk->sk_family == AF_INET6) {
 399                 struct ipv6_pinfo *np = inet6_sk(sk);
 400                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 401                 memset(&np->saddr, 0, sizeof(np->saddr));
 402 #endif
 403         }
 404 }
 405 /*
 406  * We need our own bind because there are no privileged id's == local ports.
 407  * Moreover, we don't allow binding to multi- and broadcast addresses.
 408  */
 409
 410 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 411 {
 412         struct inet_sock *isk = inet_sk(sk);
 413         unsigned short snum;
 414         int err;
 415         int dif = sk->sk_bound_dev_if;
 416
 417         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 418         if (err)
 419                 return err;
 420
 421         lock_sock(sk);
 422
 423         err = -EINVAL;
 424         if (isk->inet_num != 0)
 425                 goto out;
 426
 427         err = -EADDRINUSE;
 428         ping_set_saddr(sk, uaddr);
 429         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 430         if (ping_get_port(sk, snum) != 0) {
 431                 ping_clear_saddr(sk, dif);
 432                 goto out;
 433         }
 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_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0);
 474 }
 475
 476 /*
 477  * This routine is called by the ICMP module when it gets some
 478  * sort of error condition.
 479  */
 480
 481 void ping_err(struct sk_buff *skb, int offset, u32 info)
 482 {
 483         int family;
 484         struct icmphdr *icmph;
 485         struct inet_sock *inet_sock;
 486         int type;
 487         int code;
 488         struct net *net = dev_net(skb->dev);
 489         struct sock *sk;
 490         int harderr;
 491         int err;
 492
 493         if (skb->protocol == htons(ETH_P_IP)) {
 494                 family = AF_INET;
 495                 type = icmp_hdr(skb)->type;
 496                 code = icmp_hdr(skb)->code;
 497                 icmph = (struct icmphdr *)(skb->data + offset);
 498         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 499                 family = AF_INET6;
 500                 type = icmp6_hdr(skb)->icmp6_type;
 501                 code = icmp6_hdr(skb)->icmp6_code;
 502                 icmph = (struct icmphdr *) (skb->data + offset);
 503         } else {
 504                 BUG();
 505         }
 506
 507         /* We assume the packet has already been checked by icmp_unreach */
 508
 509         if (!ping_supported(family, icmph->type, icmph->code))
 510                 return;
 511
 512         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 513                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 514                  ntohs(icmph->un.echo.sequence));
 515
 516         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 517         if (!sk) {
 518                 pr_debug("no socket, dropping\n");
 519                 return; /* No socket for error */
 520         }
 521         pr_debug("err on socket %p\n", sk);
 522
 523         err = 0;
 524         harderr = 0;
 525         inet_sock = inet_sk(sk);
 526
 527         if (skb->protocol == htons(ETH_P_IP)) {
 528                 switch (type) {
 529                 default:
 530                 case ICMP_TIME_EXCEEDED:
 531                         err = EHOSTUNREACH;
 532                         break;
 533                 case ICMP_SOURCE_QUENCH:
 534                         /* This is not a real error but ping wants to see it.
 535                          * Report it with some fake errno.
 536                          */
 537                         err = EREMOTEIO;
 538                         break;
 539                 case ICMP_PARAMETERPROB:
 540                         err = EPROTO;
 541                         harderr = 1;
 542                         break;
 543                 case ICMP_DEST_UNREACH:
 544                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 545                                 ipv4_sk_update_pmtu(skb, sk, info);
 546                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 547                                         err = EMSGSIZE;
 548                                         harderr = 1;
 549                                         break;
 550                                 }
 551                                 goto out;
 552                         }
 553                         err = EHOSTUNREACH;
 554                         if (code <= NR_ICMP_UNREACH) {
 555                                 harderr = icmp_err_convert[code].fatal;
 556                                 err = icmp_err_convert[code].errno;
 557                         }
 558                         break;
 559                 case ICMP_REDIRECT:
 560                         /* See ICMP_SOURCE_QUENCH */
 561                         ipv4_sk_redirect(skb, sk);
 562                         err = EREMOTEIO;
 563                         break;
 564                 }
 565 #if IS_ENABLED(CONFIG_IPV6)
 566         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 567                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 568 #endif
 569         }
 570
 571         /*
 572          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 573          *      4.1.3.3.
 574          */
 575         if ((family == AF_INET && !inet_sock->recverr) ||
 576             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 577                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 578                         goto out;
 579         } else {
 580                 if (family == AF_INET) {
 581                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 582                                       info, (u8 *)icmph);
 583 #if IS_ENABLED(CONFIG_IPV6)
 584                 } else if (family == AF_INET6) {
 585                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 586                                                    info, (u8 *)icmph);
 587 #endif
 588                 }
 589         }
 590         sk->sk_err = err;
 591         sk->sk_error_report(sk);
 592 out:
 593         sock_put(sk);
 594 }
 595 EXPORT_SYMBOL_GPL(ping_err);
 596
 597 /*
 598  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 599  *      starting from the payload.
 600  */
 601
 602 int ping_getfrag(void *from, char *to,
 603                  int offset, int fraglen, int odd, struct sk_buff *skb)
 604 {
 605         struct pingfakehdr *pfh = (struct pingfakehdr *)from;
 606
 607         if (offset == 0) {
 608                 fraglen -= sizeof(struct icmphdr);
 609                 if (fraglen < 0)
 610                         BUG();
 611                 if (!csum_and_copy_from_iter_full(to + sizeof(struct icmphdr),
 612                             fraglen, &pfh->wcheck,
 613                             &pfh->msg->msg_iter))
 614                         return -EFAULT;
 615         } else if (offset < sizeof(struct icmphdr)) {
 616                         BUG();
 617         } else {
 618                 if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
 619                                             &pfh->msg->msg_iter))
 620                         return -EFAULT;
 621         }
 622
 623 #if IS_ENABLED(CONFIG_IPV6)
 624         /* For IPv6, checksum each skb as we go along, as expected by
 625          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 626          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 627          */
 628         if (pfh->family == AF_INET6) {
 629                 skb->csum = pfh->wcheck;
 630                 skb->ip_summed = CHECKSUM_NONE;
 631                 pfh->wcheck = 0;
 632         }
 633 #endif
 634
 635         return 0;
 636 }
 637 EXPORT_SYMBOL_GPL(ping_getfrag);
 638
 639 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 640                                        struct flowi4 *fl4)
 641 {
 642         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 643
 644         if (!skb)
 645                 return 0;
 646         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 647                 sizeof(struct icmphdr), pfh->wcheck);
 648         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 649         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 650         skb->ip_summed = CHECKSUM_NONE;
 651         return ip_push_pending_frames(sk, fl4);
 652 }
 653
 654 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 655                         void *user_icmph, size_t icmph_len) {
 656         u8 type, code;
 657
 658         if (len > 0xFFFF)
 659                 return -EMSGSIZE;
 660
 661         /* Must have at least a full ICMP header. */
 662         if (len < icmph_len)
 663                 return -EINVAL;
 664
 665         /*
 666          *      Check the flags.
 667          */
 668
 669         /* Mirror BSD error message compatibility */
 670         if (msg->msg_flags & MSG_OOB)
 671                 return -EOPNOTSUPP;
 672
 673         /*
 674          *      Fetch the ICMP header provided by the userland.
 675          *      iovec is modified! The ICMP header is consumed.
 676          */
 677         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 678                 return -EFAULT;
 679
 680         if (family == AF_INET) {
 681                 type = ((struct icmphdr *) user_icmph)->type;
 682                 code = ((struct icmphdr *) user_icmph)->code;
 683 #if IS_ENABLED(CONFIG_IPV6)
 684         } else if (family == AF_INET6) {
 685                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 686                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 687 #endif
 688         } else {
 689                 BUG();
 690         }
 691
 692         if (!ping_supported(family, type, code))
 693                 return -EINVAL;
 694
 695         return 0;
 696 }
 697 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 698
 699 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 700 {
 701         struct net *net = sock_net(sk);
 702         struct flowi4 fl4;
 703         struct inet_sock *inet = inet_sk(sk);
 704         struct ipcm_cookie ipc;
 705         struct icmphdr user_icmph;
 706         struct pingfakehdr pfh;
 707         struct rtable *rt = NULL;
 708         struct ip_options_data opt_copy;
 709         int free = 0;
 710         __be32 saddr, daddr, faddr;
 711         u8  tos;
 712         int err;
 713
 714         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 715
 716         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 717                                   sizeof(user_icmph));
 718         if (err)
 719                 return err;
 720
 721         /*
 722          *      Get and verify the address.
 723          */
 724
 725         if (msg->msg_name) {
 726                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 727                 if (msg->msg_namelen < sizeof(*usin))
 728                         return -EINVAL;
 729                 if (usin->sin_family != AF_INET)
 730                         return -EAFNOSUPPORT;
 731                 daddr = usin->sin_addr.s_addr;
 732                 /* no remote port */
 733         } else {
 734                 if (sk->sk_state != TCP_ESTABLISHED)
 735                         return -EDESTADDRREQ;
 736                 daddr = inet->inet_daddr;
 737                 /* no remote port */
 738         }
 739
 740         ipcm_init_sk(&ipc, inet);
 741
 742         if (msg->msg_controllen) {
 743                 err = ip_cmsg_send(sk, msg, &ipc, false);
 744                 if (unlikely(err)) {
 745                         kfree(ipc.opt);
 746                         return err;
 747                 }
 748                 if (ipc.opt)
 749                         free = 1;
 750         }
 751         if (!ipc.opt) {
 752                 struct ip_options_rcu *inet_opt;
 753
 754                 rcu_read_lock();
 755                 inet_opt = rcu_dereference(inet->inet_opt);
 756                 if (inet_opt) {
 757                         memcpy(&opt_copy, inet_opt,
 758                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 759                         ipc.opt = &opt_copy.opt;
 760                 }
 761                 rcu_read_unlock();
 762         }
 763
 764         saddr = ipc.addr;
 765         ipc.addr = faddr = daddr;
 766
 767         if (ipc.opt && ipc.opt->opt.srr) {
 768                 if (!daddr) {
 769                         err = -EINVAL;
 770                         goto out_free;
 771                 }
 772                 faddr = ipc.opt->opt.faddr;
 773         }
 774         tos = get_rttos(&ipc, inet);
 775         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 776             (msg->msg_flags & MSG_DONTROUTE) ||
 777             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 778                 tos |= RTO_ONLINK;
 779         }
 780
 781         if (ipv4_is_multicast(daddr)) {
 782                 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
 783                         ipc.oif = inet->mc_index;
 784                 if (!saddr)
 785                         saddr = inet->mc_addr;
 786         } else if (!ipc.oif)
 787                 ipc.oif = inet->uc_index;
 788
 789         flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
 790                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 791                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
 792                            sk->sk_uid);
 793
 794         security_sk_classify_flow(sk, flowi4_to_flowi(&fl4));
 795         rt = ip_route_output_flow(net, &fl4, sk);
 796         if (IS_ERR(rt)) {
 797                 err = PTR_ERR(rt);
 798                 rt = NULL;
 799                 if (err == -ENETUNREACH)
 800                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 801                 goto out;
 802         }
 803
 804         err = -EACCES;
 805         if ((rt->rt_flags & RTCF_BROADCAST) &&
 806             !sock_flag(sk, SOCK_BROADCAST))
 807                 goto out;
 808
 809         if (msg->msg_flags & MSG_CONFIRM)
 810                 goto do_confirm;
 811 back_from_confirm:
 812
 813         if (!ipc.addr)
 814                 ipc.addr = fl4.daddr;
 815
 816         lock_sock(sk);
 817
 818         pfh.icmph.type = user_icmph.type; /* already checked */
 819         pfh.icmph.code = user_icmph.code; /* ditto */
 820         pfh.icmph.checksum = 0;
 821         pfh.icmph.un.echo.id = inet->inet_sport;
 822         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 823         pfh.msg = msg;
 824         pfh.wcheck = 0;
 825         pfh.family = AF_INET;
 826
 827         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 828                         0, &ipc, &rt, msg->msg_flags);
 829         if (err)
 830                 ip_flush_pending_frames(sk);
 831         else
 832                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 833         release_sock(sk);
 834
 835 out:
 836         ip_rt_put(rt);
 837 out_free:
 838         if (free)
 839                 kfree(ipc.opt);
 840         if (!err) {
 841                 icmp_out_count(sock_net(sk), user_icmph.type);
 842                 return len;
 843         }
 844         return err;
 845
 846 do_confirm:
 847         if (msg->msg_flags & MSG_PROBE)
 848                 dst_confirm_neigh(&rt->dst, &fl4.daddr);
 849         if (!(msg->msg_flags & MSG_PROBE) || len)
 850                 goto back_from_confirm;
 851         err = 0;
 852         goto out;
 853 }
 854
 855 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 856                  int flags, int *addr_len)
 857 {
 858         struct inet_sock *isk = inet_sk(sk);
 859         int family = sk->sk_family;
 860         struct sk_buff *skb;
 861         int copied, err;
 862
 863         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 864
 865         err = -EOPNOTSUPP;
 866         if (flags & MSG_OOB)
 867                 goto out;
 868
 869         if (flags & MSG_ERRQUEUE)
 870                 return inet_recv_error(sk, msg, len, addr_len);
 871
 872         skb = skb_recv_datagram(sk, flags, noblock, &err);
 873         if (!skb)
 874                 goto out;
 875
 876         copied = skb->len;
 877         if (copied > len) {
 878                 msg->msg_flags |= MSG_TRUNC;
 879                 copied = len;
 880         }
 881
 882         /* Don't bother checking the checksum */
 883         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 884         if (err)
 885                 goto done;
 886
 887         sock_recv_timestamp(msg, sk, skb);
 888
 889         /* Copy the address and add cmsg data. */
 890         if (family == AF_INET) {
 891                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 892
 893                 if (sin) {
 894                         sin->sin_family = AF_INET;
 895                         sin->sin_port = 0 /* skb->h.uh->source */;
 896                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 897                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 898                         *addr_len = sizeof(*sin);
 899                 }
 900
 901                 if (isk->cmsg_flags)
 902                         ip_cmsg_recv(msg, skb);
 903
 904 #if IS_ENABLED(CONFIG_IPV6)
 905         } else if (family == AF_INET6) {
 906                 struct ipv6_pinfo *np = inet6_sk(sk);
 907                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 908                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 909
 910                 if (sin6) {
 911                         sin6->sin6_family = AF_INET6;
 912                         sin6->sin6_port = 0;
 913                         sin6->sin6_addr = ip6->saddr;
 914                         sin6->sin6_flowinfo = 0;
 915                         if (np->sndflow)
 916                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 917                         sin6->sin6_scope_id =
 918                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 919                                                     inet6_iif(skb));
 920                         *addr_len = sizeof(*sin6);
 921                 }
 922
 923                 if (inet6_sk(sk)->rxopt.all)
 924                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 925                 if (skb->protocol == htons(ETH_P_IPV6) &&
 926                     inet6_sk(sk)->rxopt.all)
 927                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 928                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 929                         ip_cmsg_recv(msg, skb);
 930 #endif
 931         } else {
 932                 BUG();
 933         }
 934
 935         err = copied;
 936
 937 done:
 938         skb_free_datagram(sk, skb);
 939 out:
 940         pr_debug("ping_recvmsg -> %d\n", err);
 941         return err;
 942 }
 943 EXPORT_SYMBOL_GPL(ping_recvmsg);
 944
 945 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 946 {
 947         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 948                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 949         if (sock_queue_rcv_skb(sk, skb) < 0) {
 950                 kfree_skb(skb);
 951                 pr_debug("ping_queue_rcv_skb -> failed\n");
 952                 return -1;
 953         }
 954         return 0;
 955 }
 956 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 957
 958
 959 /*
 960  *      All we need to do is get the socket.
 961  */
 962
 963 bool ping_rcv(struct sk_buff *skb)
 964 {
 965         struct sock *sk;
 966         struct net *net = dev_net(skb->dev);
 967         struct icmphdr *icmph = icmp_hdr(skb);
 968
 969         /* We assume the packet has already been checked by icmp_rcv */
 970
 971         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 972                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 973
 974         /* Push ICMP header back */
 975         skb_push(skb, skb->data - (u8 *)icmph);
 976
 977         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 978         if (sk) {
 979                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 980
 981                 pr_debug("rcv on socket %p\n", sk);
 982                 if (skb2)
 983                         ping_queue_rcv_skb(sk, skb2);
 984                 sock_put(sk);
 985                 return true;
 986         }
 987         pr_debug("no socket, dropping\n");
 988
 989         return false;
 990 }
 991 EXPORT_SYMBOL_GPL(ping_rcv);
 992
 993 struct proto ping_prot = {
 994         .name =         "PING",
 995         .owner =        THIS_MODULE,
 996         .init =         ping_init_sock,
 997         .close =        ping_close,
 998         .connect =      ip4_datagram_connect,
 999         .disconnect =   __udp_disconnect,
1000         .setsockopt =   ip_setsockopt,
1001         .getsockopt =   ip_getsockopt,
1002         .sendmsg =      ping_v4_sendmsg,
1003         .recvmsg =      ping_recvmsg,
1004         .bind =         ping_bind,
1005         .backlog_rcv =  ping_queue_rcv_skb,
1006         .release_cb =   ip4_datagram_release_cb,
1007         .hash =         ping_hash,
1008         .unhash =       ping_unhash,
1009         .get_port =     ping_get_port,
1010         .obj_size =     sizeof(struct inet_sock),
1011 };
1012 EXPORT_SYMBOL(ping_prot);
1013
1014 #ifdef CONFIG_PROC_FS
1015
1016 static struct sock *ping_get_first(struct seq_file *seq, int start)
1017 {
1018         struct sock *sk;
1019         struct ping_iter_state *state = seq->private;
1020         struct net *net = seq_file_net(seq);
1021
1022         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1023              ++state->bucket) {
1024                 struct hlist_nulls_node *node;
1025                 struct hlist_nulls_head *hslot;
1026
1027                 hslot = &ping_table.hash[state->bucket];
1028
1029                 if (hlist_nulls_empty(hslot))
1030                         continue;
1031
1032                 sk_nulls_for_each(sk, node, hslot) {
1033                         if (net_eq(sock_net(sk), net) &&
1034                             sk->sk_family == state->family)
1035                                 goto found;
1036                 }
1037         }
1038         sk = NULL;
1039 found:
1040         return sk;
1041 }
1042
1043 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1044 {
1045         struct ping_iter_state *state = seq->private;
1046         struct net *net = seq_file_net(seq);
1047
1048         do {
1049                 sk = sk_nulls_next(sk);
1050         } while (sk && (!net_eq(sock_net(sk), net)));
1051
1052         if (!sk)
1053                 return ping_get_first(seq, state->bucket + 1);
1054         return sk;
1055 }
1056
1057 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1058 {
1059         struct sock *sk = ping_get_first(seq, 0);
1060
1061         if (sk)
1062                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1063                         --pos;
1064         return pos ? NULL : sk;
1065 }
1066
1067 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1068         __acquires(ping_table.lock)
1069 {
1070         struct ping_iter_state *state = seq->private;
1071         state->bucket = 0;
1072         state->family = family;
1073
1074         read_lock_bh(&ping_table.lock);
1075
1076         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1077 }
1078 EXPORT_SYMBOL_GPL(ping_seq_start);
1079
1080 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1081 {
1082         return ping_seq_start(seq, pos, AF_INET);
1083 }
1084
1085 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1086 {
1087         struct sock *sk;
1088
1089         if (v == SEQ_START_TOKEN)
1090                 sk = ping_get_idx(seq, 0);
1091         else
1092                 sk = ping_get_next(seq, v);
1093
1094         ++*pos;
1095         return sk;
1096 }
1097 EXPORT_SYMBOL_GPL(ping_seq_next);
1098
1099 void ping_seq_stop(struct seq_file *seq, void *v)
1100         __releases(ping_table.lock)
1101 {
1102         read_unlock_bh(&ping_table.lock);
1103 }
1104 EXPORT_SYMBOL_GPL(ping_seq_stop);
1105
1106 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1107                 int bucket)
1108 {
1109         struct inet_sock *inet = inet_sk(sp);
1110         __be32 dest = inet->inet_daddr;
1111         __be32 src = inet->inet_rcv_saddr;
1112         __u16 destp = ntohs(inet->inet_dport);
1113         __u16 srcp = ntohs(inet->inet_sport);
1114
1115         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1116                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
1117                 bucket, src, srcp, dest, destp, sp->sk_state,
1118                 sk_wmem_alloc_get(sp),
1119                 sk_rmem_alloc_get(sp),
1120                 0, 0L, 0,
1121                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1122                 0, sock_i_ino(sp),
1123                 refcount_read(&sp->sk_refcnt), sp,
1124                 atomic_read(&sp->sk_drops));
1125 }
1126
1127 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1128 {
1129         seq_setwidth(seq, 127);
1130         if (v == SEQ_START_TOKEN)
1131                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1132                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1133                            "inode ref pointer drops");
1134         else {
1135                 struct ping_iter_state *state = seq->private;
1136
1137                 ping_v4_format_sock(v, seq, state->bucket);
1138         }
1139         seq_pad(seq, '\n');
1140         return 0;
1141 }
1142
1143 static const struct seq_operations ping_v4_seq_ops = {
1144         .start          = ping_v4_seq_start,
1145         .show           = ping_v4_seq_show,
1146         .next           = ping_seq_next,
1147         .stop           = ping_seq_stop,
1148 };
1149
1150 static int __net_init ping_v4_proc_init_net(struct net *net)
1151 {
1152         if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
1153                         sizeof(struct ping_iter_state)))
1154                 return -ENOMEM;
1155         return 0;
1156 }
1157
1158 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1159 {
1160         remove_proc_entry("icmp", net->proc_net);
1161 }
1162
1163 static struct pernet_operations ping_v4_net_ops = {
1164         .init = ping_v4_proc_init_net,
1165         .exit = ping_v4_proc_exit_net,
1166 };
1167
1168 int __init ping_proc_init(void)
1169 {
1170         return register_pernet_subsys(&ping_v4_net_ops);
1171 }
1172
1173 void ping_proc_exit(void)
1174 {
1175         unregister_pernet_subsys(&ping_v4_net_ops);
1176 }
1177
1178 #endif
1179
1180 void __init ping_init(void)
1181 {
1182         int i;
1183
1184         for (i = 0; i < PING_HTABLE_SIZE; i++)
1185                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1186         rwlock_init(&ping_table.lock);
1187 }