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 void 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
 154 void ping_unhash(struct sock *sk)
 155 {
 156         struct inet_sock *isk = inet_sk(sk);
 157         pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
 158         if (sk_hashed(sk)) {
 159                 write_lock_bh(&ping_table.lock);
 160                 hlist_nulls_del(&sk->sk_nulls_node);
 161                 sk_nulls_node_init(&sk->sk_nulls_node);
 162                 sock_put(sk);
 163                 isk->inet_num = 0;
 164                 isk->inet_sport = 0;
 165                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 166                 write_unlock_bh(&ping_table.lock);
 167         }
 168 }
 169 EXPORT_SYMBOL_GPL(ping_unhash);
 170
 171 static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 172 {
 173         struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
 174         struct sock *sk = NULL;
 175         struct inet_sock *isk;
 176         struct hlist_nulls_node *hnode;
 177         int dif = skb->dev->ifindex;
 178
 179         if (skb->protocol == htons(ETH_P_IP)) {
 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                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 185                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
 186 #endif
 187         }
 188
 189         read_lock_bh(&ping_table.lock);
 190
 191         ping_portaddr_for_each_entry(sk, hnode, hslot) {
 192                 isk = inet_sk(sk);
 193
 194                 pr_debug("iterate\n");
 195                 if (isk->inet_num != ident)
 196                         continue;
 197
 198                 if (skb->protocol == htons(ETH_P_IP) &&
 199                     sk->sk_family == AF_INET) {
 200                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 201                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
 202                                  sk->sk_bound_dev_if);
 203
 204                         if (isk->inet_rcv_saddr &&
 205                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 206                                 continue;
 207 #if IS_ENABLED(CONFIG_IPV6)
 208                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
 209                            sk->sk_family == AF_INET6) {
 210
 211                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 212                                  (int) isk->inet_num,
 213                                  &sk->sk_v6_rcv_saddr,
 214                                  sk->sk_bound_dev_if);
 215
 216                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 217                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 218                                              &ipv6_hdr(skb)->daddr))
 219                                 continue;
 220 #endif
 221                 } else {
 222                         continue;
 223                 }
 224
 225                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
 226                         continue;
 227
 228                 sock_hold(sk);
 229                 goto exit;
 230         }
 231
 232         sk = NULL;
 233 exit:
 234         read_unlock_bh(&ping_table.lock);
 235
 236         return sk;
 237 }
 238
 239 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 240                                           kgid_t *high)
 241 {
 242         kgid_t *data = net->ipv4.ping_group_range.range;
 243         unsigned int seq;
 244
 245         do {
 246                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 247
 248                 *low = data[0];
 249                 *high = data[1];
 250         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 251 }
 252
 253
 254 int ping_init_sock(struct sock *sk)
 255 {
 256         struct net *net = sock_net(sk);
 257         kgid_t group = current_egid();
 258         struct group_info *group_info;
 259         int i, j, count;
 260         kgid_t low, high;
 261         int ret = 0;
 262
 263         if (sk->sk_family == AF_INET6)
 264                 sk->sk_ipv6only = 1;
 265
 266         inet_get_ping_group_range_net(net, &low, &high);
 267         if (gid_lte(low, group) && gid_lte(group, high))
 268                 return 0;
 269
 270         group_info = get_current_groups();
 271         count = group_info->ngroups;
 272         for (i = 0; i < group_info->nblocks; i++) {
 273                 int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
 274                 for (j = 0; j < cp_count; j++) {
 275                         kgid_t gid = group_info->blocks[i][j];
 276                         if (gid_lte(low, gid) && gid_lte(gid, high))
 277                                 goto out_release_group;
 278                 }
 279
 280                 count -= cp_count;
 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", sk->sk_refcnt.counter);
 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         struct net *net = sock_net(sk);
 305         if (sk->sk_family == AF_INET) {
 306                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 307                 int chk_addr_ret;
 308
 309                 if (addr_len < sizeof(*addr))
 310                         return -EINVAL;
 311
 312                 if (addr->sin_family != AF_INET &&
 313                     !(addr->sin_family == AF_UNSPEC &&
 314                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 315                         return -EAFNOSUPPORT;
 316
 317                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 318                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 319
 320                 chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
 321
 322                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 323                         chk_addr_ret = RTN_LOCAL;
 324
 325                 if ((net->ipv4.sysctl_ip_nonlocal_bind == 0 &&
 326                     isk->freebind == 0 && isk->transparent == 0 &&
 327                      chk_addr_ret != RTN_LOCAL) ||
 328                     chk_addr_ret == RTN_MULTICAST ||
 329                     chk_addr_ret == RTN_BROADCAST)
 330                         return -EADDRNOTAVAIL;
 331
 332 #if IS_ENABLED(CONFIG_IPV6)
 333         } else if (sk->sk_family == AF_INET6) {
 334                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 335                 int addr_type, scoped, has_addr;
 336                 struct net_device *dev = NULL;
 337
 338                 if (addr_len < sizeof(*addr))
 339                         return -EINVAL;
 340
 341                 if (addr->sin6_family != AF_INET6)
 342                         return -EAFNOSUPPORT;
 343
 344                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 345                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 346
 347                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 348                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 349                 if ((addr_type != IPV6_ADDR_ANY &&
 350                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 351                     (scoped && !addr->sin6_scope_id))
 352                         return -EINVAL;
 353
 354                 rcu_read_lock();
 355                 if (addr->sin6_scope_id) {
 356                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 357                         if (!dev) {
 358                                 rcu_read_unlock();
 359                                 return -ENODEV;
 360                         }
 361                 }
 362                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 363                                                     scoped);
 364                 rcu_read_unlock();
 365
 366                 if (!(net->ipv6.sysctl.ip_nonlocal_bind ||
 367                       isk->freebind || isk->transparent || has_addr ||
 368                       addr_type == IPV6_ADDR_ANY))
 369                         return -EADDRNOTAVAIL;
 370
 371                 if (scoped)
 372                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 373 #endif
 374         } else {
 375                 return -EAFNOSUPPORT;
 376         }
 377         return 0;
 378 }
 379
 380 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 381 {
 382         if (saddr->sa_family == AF_INET) {
 383                 struct inet_sock *isk = inet_sk(sk);
 384                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 385                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 386 #if IS_ENABLED(CONFIG_IPV6)
 387         } else if (saddr->sa_family == AF_INET6) {
 388                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 389                 struct ipv6_pinfo *np = inet6_sk(sk);
 390                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 391 #endif
 392         }
 393 }
 394
 395 static void ping_clear_saddr(struct sock *sk, int dif)
 396 {
 397         sk->sk_bound_dev_if = dif;
 398         if (sk->sk_family == AF_INET) {
 399                 struct inet_sock *isk = inet_sk(sk);
 400                 isk->inet_rcv_saddr = isk->inet_saddr = 0;
 401 #if IS_ENABLED(CONFIG_IPV6)
 402         } else if (sk->sk_family == AF_INET6) {
 403                 struct ipv6_pinfo *np = inet6_sk(sk);
 404                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 405                 memset(&np->saddr, 0, sizeof(np->saddr));
 406 #endif
 407         }
 408 }
 409 /*
 410  * We need our own bind because there are no privileged id's == local ports.
 411  * Moreover, we don't allow binding to multi- and broadcast addresses.
 412  */
 413
 414 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 415 {
 416         struct inet_sock *isk = inet_sk(sk);
 417         unsigned short snum;
 418         int err;
 419         int dif = sk->sk_bound_dev_if;
 420
 421         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 422         if (err)
 423                 return err;
 424
 425         lock_sock(sk);
 426
 427         err = -EINVAL;
 428         if (isk->inet_num != 0)
 429                 goto out;
 430
 431         err = -EADDRINUSE;
 432         ping_set_saddr(sk, uaddr);
 433         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 434         if (ping_get_port(sk, snum) != 0) {
 435                 ping_clear_saddr(sk, dif);
 436                 goto out;
 437         }
 438
 439         pr_debug("after bind(): num = %d, dif = %d\n",
 440                  (int)isk->inet_num,
 441                  (int)sk->sk_bound_dev_if);
 442
 443         err = 0;
 444         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 445                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 446 #if IS_ENABLED(CONFIG_IPV6)
 447         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 448                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 449 #endif
 450
 451         if (snum)
 452                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 453         isk->inet_sport = htons(isk->inet_num);
 454         isk->inet_daddr = 0;
 455         isk->inet_dport = 0;
 456
 457 #if IS_ENABLED(CONFIG_IPV6)
 458         if (sk->sk_family == AF_INET6)
 459                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 460 #endif
 461
 462         sk_dst_reset(sk);
 463 out:
 464         release_sock(sk);
 465         pr_debug("ping_v4_bind -> %d\n", err);
 466         return err;
 467 }
 468 EXPORT_SYMBOL_GPL(ping_bind);
 469
 470 /*
 471  * Is this a supported type of ICMP message?
 472  */
 473
 474 static inline int ping_supported(int family, int type, int code)
 475 {
 476         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 477                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0);
 478 }
 479
 480 /*
 481  * This routine is called by the ICMP module when it gets some
 482  * sort of error condition.
 483  */
 484
 485 void ping_err(struct sk_buff *skb, int offset, u32 info)
 486 {
 487         int family;
 488         struct icmphdr *icmph;
 489         struct inet_sock *inet_sock;
 490         int type;
 491         int code;
 492         struct net *net = dev_net(skb->dev);
 493         struct sock *sk;
 494         int harderr;
 495         int err;
 496
 497         if (skb->protocol == htons(ETH_P_IP)) {
 498                 family = AF_INET;
 499                 type = icmp_hdr(skb)->type;
 500                 code = icmp_hdr(skb)->code;
 501                 icmph = (struct icmphdr *)(skb->data + offset);
 502         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 503                 family = AF_INET6;
 504                 type = icmp6_hdr(skb)->icmp6_type;
 505                 code = icmp6_hdr(skb)->icmp6_code;
 506                 icmph = (struct icmphdr *) (skb->data + offset);
 507         } else {
 508                 BUG();
 509         }
 510
 511         /* We assume the packet has already been checked by icmp_unreach */
 512
 513         if (!ping_supported(family, icmph->type, icmph->code))
 514                 return;
 515
 516         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 517                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 518                  ntohs(icmph->un.echo.sequence));
 519
 520         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 521         if (!sk) {
 522                 pr_debug("no socket, dropping\n");
 523                 return; /* No socket for error */
 524         }
 525         pr_debug("err on socket %p\n", sk);
 526
 527         err = 0;
 528         harderr = 0;
 529         inet_sock = inet_sk(sk);
 530
 531         if (skb->protocol == htons(ETH_P_IP)) {
 532                 switch (type) {
 533                 default:
 534                 case ICMP_TIME_EXCEEDED:
 535                         err = EHOSTUNREACH;
 536                         break;
 537                 case ICMP_SOURCE_QUENCH:
 538                         /* This is not a real error but ping wants to see it.
 539                          * Report it with some fake errno.
 540                          */
 541                         err = EREMOTEIO;
 542                         break;
 543                 case ICMP_PARAMETERPROB:
 544                         err = EPROTO;
 545                         harderr = 1;
 546                         break;
 547                 case ICMP_DEST_UNREACH:
 548                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 549                                 ipv4_sk_update_pmtu(skb, sk, info);
 550                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 551                                         err = EMSGSIZE;
 552                                         harderr = 1;
 553                                         break;
 554                                 }
 555                                 goto out;
 556                         }
 557                         err = EHOSTUNREACH;
 558                         if (code <= NR_ICMP_UNREACH) {
 559                                 harderr = icmp_err_convert[code].fatal;
 560                                 err = icmp_err_convert[code].errno;
 561                         }
 562                         break;
 563                 case ICMP_REDIRECT:
 564                         /* See ICMP_SOURCE_QUENCH */
 565                         ipv4_sk_redirect(skb, sk);
 566                         err = EREMOTEIO;
 567                         break;
 568                 }
 569 #if IS_ENABLED(CONFIG_IPV6)
 570         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 571                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 572 #endif
 573         }
 574
 575         /*
 576          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 577          *      4.1.3.3.
 578          */
 579         if ((family == AF_INET && !inet_sock->recverr) ||
 580             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 581                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 582                         goto out;
 583         } else {
 584                 if (family == AF_INET) {
 585                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 586                                       info, (u8 *)icmph);
 587 #if IS_ENABLED(CONFIG_IPV6)
 588                 } else if (family == AF_INET6) {
 589                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 590                                                    info, (u8 *)icmph);
 591 #endif
 592                 }
 593         }
 594         sk->sk_err = err;
 595         sk->sk_error_report(sk);
 596 out:
 597         sock_put(sk);
 598 }
 599 EXPORT_SYMBOL_GPL(ping_err);
 600
 601 /*
 602  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 603  *      starting from the payload.
 604  */
 605
 606 int ping_getfrag(void *from, char *to,
 607                  int offset, int fraglen, int odd, struct sk_buff *skb)
 608 {
 609         struct pingfakehdr *pfh = (struct pingfakehdr *)from;
 610
 611         if (offset == 0) {
 612                 fraglen -= sizeof(struct icmphdr);
 613                 if (fraglen < 0)
 614                         BUG();
 615                 if (csum_and_copy_from_iter(to + sizeof(struct icmphdr),
 616                             fraglen, &pfh->wcheck,
 617                             &pfh->msg->msg_iter) != fraglen)
 618                         return -EFAULT;
 619         } else if (offset < sizeof(struct icmphdr)) {
 620                         BUG();
 621         } else {
 622                 if (csum_and_copy_from_iter(to, fraglen, &pfh->wcheck,
 623                                             &pfh->msg->msg_iter) != fraglen)
 624                         return -EFAULT;
 625         }
 626
 627 #if IS_ENABLED(CONFIG_IPV6)
 628         /* For IPv6, checksum each skb as we go along, as expected by
 629          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 630          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 631          */
 632         if (pfh->family == AF_INET6) {
 633                 skb->csum = pfh->wcheck;
 634                 skb->ip_summed = CHECKSUM_NONE;
 635                 pfh->wcheck = 0;
 636         }
 637 #endif
 638
 639         return 0;
 640 }
 641 EXPORT_SYMBOL_GPL(ping_getfrag);
 642
 643 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 644                                        struct flowi4 *fl4)
 645 {
 646         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 647
 648         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 649                 sizeof(struct icmphdr), pfh->wcheck);
 650         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 651         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 652         skb->ip_summed = CHECKSUM_NONE;
 653         return ip_push_pending_frames(sk, fl4);
 654 }
 655
 656 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 657                         void *user_icmph, size_t icmph_len) {
 658         u8 type, code;
 659
 660         if (len > 0xFFFF)
 661                 return -EMSGSIZE;
 662
 663         /*
 664          *      Check the flags.
 665          */
 666
 667         /* Mirror BSD error message compatibility */
 668         if (msg->msg_flags & MSG_OOB)
 669                 return -EOPNOTSUPP;
 670
 671         /*
 672          *      Fetch the ICMP header provided by the userland.
 673          *      iovec is modified! The ICMP header is consumed.
 674          */
 675         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 676                 return -EFAULT;
 677
 678         if (family == AF_INET) {
 679                 type = ((struct icmphdr *) user_icmph)->type;
 680                 code = ((struct icmphdr *) user_icmph)->code;
 681 #if IS_ENABLED(CONFIG_IPV6)
 682         } else if (family == AF_INET6) {
 683                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 684                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 685 #endif
 686         } else {
 687                 BUG();
 688         }
 689
 690         if (!ping_supported(family, type, code))
 691                 return -EINVAL;
 692
 693         return 0;
 694 }
 695 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 696
 697 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 698 {
 699         struct net *net = sock_net(sk);
 700         struct flowi4 fl4;
 701         struct inet_sock *inet = inet_sk(sk);
 702         struct ipcm_cookie ipc;
 703         struct icmphdr user_icmph;
 704         struct pingfakehdr pfh;
 705         struct rtable *rt = NULL;
 706         struct ip_options_data opt_copy;
 707         int free = 0;
 708         __be32 saddr, daddr, faddr;
 709         u8  tos;
 710         int err;
 711
 712         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 713
 714         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 715                                   sizeof(user_icmph));
 716         if (err)
 717                 return err;
 718
 719         /*
 720          *      Get and verify the address.
 721          */
 722
 723         if (msg->msg_name) {
 724                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 725                 if (msg->msg_namelen < sizeof(*usin))
 726                         return -EINVAL;
 727                 if (usin->sin_family != AF_INET)
 728                         return -EAFNOSUPPORT;
 729                 daddr = usin->sin_addr.s_addr;
 730                 /* no remote port */
 731         } else {
 732                 if (sk->sk_state != TCP_ESTABLISHED)
 733                         return -EDESTADDRREQ;
 734                 daddr = inet->inet_daddr;
 735                 /* no remote port */
 736         }
 737
 738         ipc.addr = inet->inet_saddr;
 739         ipc.opt = NULL;
 740         ipc.oif = sk->sk_bound_dev_if;
 741         ipc.tx_flags = 0;
 742         ipc.ttl = 0;
 743         ipc.tos = -1;
 744
 745         sock_tx_timestamp(sk, &ipc.tx_flags);
 746
 747         if (msg->msg_controllen) {
 748                 err = ip_cmsg_send(sock_net(sk), msg, &ipc, false);
 749                 if (err)
 750                         return err;
 751                 if (ipc.opt)
 752                         free = 1;
 753         }
 754         if (!ipc.opt) {
 755                 struct ip_options_rcu *inet_opt;
 756
 757                 rcu_read_lock();
 758                 inet_opt = rcu_dereference(inet->inet_opt);
 759                 if (inet_opt) {
 760                         memcpy(&opt_copy, inet_opt,
 761                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 762                         ipc.opt = &opt_copy.opt;
 763                 }
 764                 rcu_read_unlock();
 765         }
 766
 767         saddr = ipc.addr;
 768         ipc.addr = faddr = daddr;
 769
 770         if (ipc.opt && ipc.opt->opt.srr) {
 771                 if (!daddr)
 772                         return -EINVAL;
 773                 faddr = ipc.opt->opt.faddr;
 774         }
 775         tos = get_rttos(&ipc, inet);
 776         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 777             (msg->msg_flags & MSG_DONTROUTE) ||
 778             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 779                 tos |= RTO_ONLINK;
 780         }
 781
 782         if (ipv4_is_multicast(daddr)) {
 783                 if (!ipc.oif)
 784                         ipc.oif = inet->mc_index;
 785                 if (!saddr)
 786                         saddr = inet->mc_addr;
 787         } else if (!ipc.oif)
 788                 ipc.oif = inet->uc_index;
 789
 790         flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
 791                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 792                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0);
 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         if (free)
 838                 kfree(ipc.opt);
 839         if (!err) {
 840                 icmp_out_count(sock_net(sk), user_icmph.type);
 841                 return len;
 842         }
 843         return err;
 844
 845 do_confirm:
 846         dst_confirm(&rt->dst);
 847         if (!(msg->msg_flags & MSG_PROBE) || len)
 848                 goto back_from_confirm;
 849         err = 0;
 850         goto out;
 851 }
 852
 853 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 854                  int flags, int *addr_len)
 855 {
 856         struct inet_sock *isk = inet_sk(sk);
 857         int family = sk->sk_family;
 858         struct sk_buff *skb;
 859         int copied, err;
 860
 861         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 862
 863         err = -EOPNOTSUPP;
 864         if (flags & MSG_OOB)
 865                 goto out;
 866
 867         if (flags & MSG_ERRQUEUE)
 868                 return inet_recv_error(sk, msg, len, addr_len);
 869
 870         skb = skb_recv_datagram(sk, flags, noblock, &err);
 871         if (!skb)
 872                 goto out;
 873
 874         copied = skb->len;
 875         if (copied > len) {
 876                 msg->msg_flags |= MSG_TRUNC;
 877                 copied = len;
 878         }
 879
 880         /* Don't bother checking the checksum */
 881         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 882         if (err)
 883                 goto done;
 884
 885         sock_recv_timestamp(msg, sk, skb);
 886
 887         /* Copy the address and add cmsg data. */
 888         if (family == AF_INET) {
 889                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 890
 891                 if (sin) {
 892                         sin->sin_family = AF_INET;
 893                         sin->sin_port = 0 /* skb->h.uh->source */;
 894                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 895                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 896                         *addr_len = sizeof(*sin);
 897                 }
 898
 899                 if (isk->cmsg_flags)
 900                         ip_cmsg_recv(msg, skb);
 901
 902 #if IS_ENABLED(CONFIG_IPV6)
 903         } else if (family == AF_INET6) {
 904                 struct ipv6_pinfo *np = inet6_sk(sk);
 905                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 906                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 907
 908                 if (sin6) {
 909                         sin6->sin6_family = AF_INET6;
 910                         sin6->sin6_port = 0;
 911                         sin6->sin6_addr = ip6->saddr;
 912                         sin6->sin6_flowinfo = 0;
 913                         if (np->sndflow)
 914                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 915                         sin6->sin6_scope_id =
 916                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 917                                                     inet6_iif(skb));
 918                         *addr_len = sizeof(*sin6);
 919                 }
 920
 921                 if (inet6_sk(sk)->rxopt.all)
 922                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 923                 if (skb->protocol == htons(ETH_P_IPV6) &&
 924                     inet6_sk(sk)->rxopt.all)
 925                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 926                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 927                         ip_cmsg_recv(msg, skb);
 928 #endif
 929         } else {
 930                 BUG();
 931         }
 932
 933         err = copied;
 934
 935 done:
 936         skb_free_datagram(sk, skb);
 937 out:
 938         pr_debug("ping_recvmsg -> %d\n", err);
 939         return err;
 940 }
 941 EXPORT_SYMBOL_GPL(ping_recvmsg);
 942
 943 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 944 {
 945         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 946                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 947         if (sock_queue_rcv_skb(sk, skb) < 0) {
 948                 kfree_skb(skb);
 949                 pr_debug("ping_queue_rcv_skb -> failed\n");
 950                 return -1;
 951         }
 952         return 0;
 953 }
 954 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 955
 956
 957 /*
 958  *      All we need to do is get the socket.
 959  */
 960
 961 bool ping_rcv(struct sk_buff *skb)
 962 {
 963         struct sock *sk;
 964         struct net *net = dev_net(skb->dev);
 965         struct icmphdr *icmph = icmp_hdr(skb);
 966
 967         /* We assume the packet has already been checked by icmp_rcv */
 968
 969         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 970                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 971
 972         /* Push ICMP header back */
 973         skb_push(skb, skb->data - (u8 *)icmph);
 974
 975         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 976         if (sk) {
 977                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 978
 979                 pr_debug("rcv on socket %p\n", sk);
 980                 if (skb2)
 981                         ping_queue_rcv_skb(sk, skb2);
 982                 sock_put(sk);
 983                 return true;
 984         }
 985         pr_debug("no socket, dropping\n");
 986
 987         return false;
 988 }
 989 EXPORT_SYMBOL_GPL(ping_rcv);
 990
 991 struct proto ping_prot = {
 992         .name =         "PING",
 993         .owner =        THIS_MODULE,
 994         .init =         ping_init_sock,
 995         .close =        ping_close,
 996         .connect =      ip4_datagram_connect,
 997         .disconnect =   udp_disconnect,
 998         .setsockopt =   ip_setsockopt,
 999         .getsockopt =   ip_getsockopt,
1000         .sendmsg =      ping_v4_sendmsg,
1001         .recvmsg =      ping_recvmsg,
1002         .bind =         ping_bind,
1003         .backlog_rcv =  ping_queue_rcv_skb,
1004         .release_cb =   ip4_datagram_release_cb,
1005         .hash =         ping_hash,
1006         .unhash =       ping_unhash,
1007         .get_port =     ping_get_port,
1008         .obj_size =     sizeof(struct inet_sock),
1009 };
1010 EXPORT_SYMBOL(ping_prot);
1011
1012 #ifdef CONFIG_PROC_FS
1013
1014 static struct sock *ping_get_first(struct seq_file *seq, int start)
1015 {
1016         struct sock *sk;
1017         struct ping_iter_state *state = seq->private;
1018         struct net *net = seq_file_net(seq);
1019
1020         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1021              ++state->bucket) {
1022                 struct hlist_nulls_node *node;
1023                 struct hlist_nulls_head *hslot;
1024
1025                 hslot = &ping_table.hash[state->bucket];
1026
1027                 if (hlist_nulls_empty(hslot))
1028                         continue;
1029
1030                 sk_nulls_for_each(sk, node, hslot) {
1031                         if (net_eq(sock_net(sk), net) &&
1032                             sk->sk_family == state->family)
1033                                 goto found;
1034                 }
1035         }
1036         sk = NULL;
1037 found:
1038         return sk;
1039 }
1040
1041 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1042 {
1043         struct ping_iter_state *state = seq->private;
1044         struct net *net = seq_file_net(seq);
1045
1046         do {
1047                 sk = sk_nulls_next(sk);
1048         } while (sk && (!net_eq(sock_net(sk), net)));
1049
1050         if (!sk)
1051                 return ping_get_first(seq, state->bucket + 1);
1052         return sk;
1053 }
1054
1055 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1056 {
1057         struct sock *sk = ping_get_first(seq, 0);
1058
1059         if (sk)
1060                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1061                         --pos;
1062         return pos ? NULL : sk;
1063 }
1064
1065 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1066 {
1067         struct ping_iter_state *state = seq->private;
1068         state->bucket = 0;
1069         state->family = family;
1070
1071         read_lock_bh(&ping_table.lock);
1072
1073         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1074 }
1075 EXPORT_SYMBOL_GPL(ping_seq_start);
1076
1077 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1078 {
1079         return ping_seq_start(seq, pos, AF_INET);
1080 }
1081
1082 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1083 {
1084         struct sock *sk;
1085
1086         if (v == SEQ_START_TOKEN)
1087                 sk = ping_get_idx(seq, 0);
1088         else
1089                 sk = ping_get_next(seq, v);
1090
1091         ++*pos;
1092         return sk;
1093 }
1094 EXPORT_SYMBOL_GPL(ping_seq_next);
1095
1096 void ping_seq_stop(struct seq_file *seq, void *v)
1097 {
1098         read_unlock_bh(&ping_table.lock);
1099 }
1100 EXPORT_SYMBOL_GPL(ping_seq_stop);
1101
1102 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1103                 int bucket)
1104 {
1105         struct inet_sock *inet = inet_sk(sp);
1106         __be32 dest = inet->inet_daddr;
1107         __be32 src = inet->inet_rcv_saddr;
1108         __u16 destp = ntohs(inet->inet_dport);
1109         __u16 srcp = ntohs(inet->inet_sport);
1110
1111         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1112                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
1113                 bucket, src, srcp, dest, destp, sp->sk_state,
1114                 sk_wmem_alloc_get(sp),
1115                 sk_rmem_alloc_get(sp),
1116                 0, 0L, 0,
1117                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1118                 0, sock_i_ino(sp),
1119                 atomic_read(&sp->sk_refcnt), sp,
1120                 atomic_read(&sp->sk_drops));
1121 }
1122
1123 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1124 {
1125         seq_setwidth(seq, 127);
1126         if (v == SEQ_START_TOKEN)
1127                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1128                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1129                            "inode ref pointer drops");
1130         else {
1131                 struct ping_iter_state *state = seq->private;
1132
1133                 ping_v4_format_sock(v, seq, state->bucket);
1134         }
1135         seq_pad(seq, '\n');
1136         return 0;
1137 }
1138
1139 static const struct seq_operations ping_v4_seq_ops = {
1140         .show           = ping_v4_seq_show,
1141         .start          = ping_v4_seq_start,
1142         .next           = ping_seq_next,
1143         .stop           = ping_seq_stop,
1144 };
1145
1146 static int ping_seq_open(struct inode *inode, struct file *file)
1147 {
1148         struct ping_seq_afinfo *afinfo = PDE_DATA(inode);
1149         return seq_open_net(inode, file, &afinfo->seq_ops,
1150                            sizeof(struct ping_iter_state));
1151 }
1152
1153 const struct file_operations ping_seq_fops = {
1154         .open           = ping_seq_open,
1155         .read           = seq_read,
1156         .llseek         = seq_lseek,
1157         .release        = seq_release_net,
1158 };
1159 EXPORT_SYMBOL_GPL(ping_seq_fops);
1160
1161 static struct ping_seq_afinfo ping_v4_seq_afinfo = {
1162         .name           = "icmp",
1163         .family         = AF_INET,
1164         .seq_fops       = &ping_seq_fops,
1165         .seq_ops        = {
1166                 .start          = ping_v4_seq_start,
1167                 .show           = ping_v4_seq_show,
1168                 .next           = ping_seq_next,
1169                 .stop           = ping_seq_stop,
1170         },
1171 };
1172
1173 int ping_proc_register(struct net *net, struct ping_seq_afinfo *afinfo)
1174 {
1175         struct proc_dir_entry *p;
1176         p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
1177                              afinfo->seq_fops, afinfo);
1178         if (!p)
1179                 return -ENOMEM;
1180         return 0;
1181 }
1182 EXPORT_SYMBOL_GPL(ping_proc_register);
1183
1184 void ping_proc_unregister(struct net *net, struct ping_seq_afinfo *afinfo)
1185 {
1186         remove_proc_entry(afinfo->name, net->proc_net);
1187 }
1188 EXPORT_SYMBOL_GPL(ping_proc_unregister);
1189
1190 static int __net_init ping_v4_proc_init_net(struct net *net)
1191 {
1192         return ping_proc_register(net, &ping_v4_seq_afinfo);
1193 }
1194
1195 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1196 {
1197         ping_proc_unregister(net, &ping_v4_seq_afinfo);
1198 }
1199
1200 static struct pernet_operations ping_v4_net_ops = {
1201         .init = ping_v4_proc_init_net,
1202         .exit = ping_v4_proc_exit_net,
1203 };
1204
1205 int __init ping_proc_init(void)
1206 {
1207         return register_pernet_subsys(&ping_v4_net_ops);
1208 }
1209
1210 void ping_proc_exit(void)
1211 {
1212         unregister_pernet_subsys(&ping_v4_net_ops);
1213 }
1214
1215 #endif
1216
1217 void __init ping_init(void)
1218 {
1219         int i;
1220
1221         for (i = 0; i < PING_HTABLE_SIZE; i++)
1222                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1223         rwlock_init(&ping_table.lock);
1224 }