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         pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
 160         if (sk_hashed(sk)) {
 161                 write_lock_bh(&ping_table.lock);
 162                 hlist_nulls_del(&sk->sk_nulls_node);
 163                 sk_nulls_node_init(&sk->sk_nulls_node);
 164                 sock_put(sk);
 165                 isk->inet_num = 0;
 166                 isk->inet_sport = 0;
 167                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 168                 write_unlock_bh(&ping_table.lock);
 169         }
 170 }
 171 EXPORT_SYMBOL_GPL(ping_unhash);
 172
 173 static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 174 {
 175         struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
 176         struct sock *sk = NULL;
 177         struct inet_sock *isk;
 178         struct hlist_nulls_node *hnode;
 179         int dif = skb->dev->ifindex;
 180
 181         if (skb->protocol == htons(ETH_P_IP)) {
 182                 pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
 183                          (int)ident, &ip_hdr(skb)->daddr, dif);
 184 #if IS_ENABLED(CONFIG_IPV6)
 185         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 186                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 187                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
 188 #endif
 189         }
 190
 191         read_lock_bh(&ping_table.lock);
 192
 193         ping_portaddr_for_each_entry(sk, hnode, hslot) {
 194                 isk = inet_sk(sk);
 195
 196                 pr_debug("iterate\n");
 197                 if (isk->inet_num != ident)
 198                         continue;
 199
 200                 if (skb->protocol == htons(ETH_P_IP) &&
 201                     sk->sk_family == AF_INET) {
 202                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 203                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
 204                                  sk->sk_bound_dev_if);
 205
 206                         if (isk->inet_rcv_saddr &&
 207                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 208                                 continue;
 209 #if IS_ENABLED(CONFIG_IPV6)
 210                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
 211                            sk->sk_family == AF_INET6) {
 212
 213                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 214                                  (int) isk->inet_num,
 215                                  &sk->sk_v6_rcv_saddr,
 216                                  sk->sk_bound_dev_if);
 217
 218                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 219                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 220                                              &ipv6_hdr(skb)->daddr))
 221                                 continue;
 222 #endif
 223                 } else {
 224                         continue;
 225                 }
 226
 227                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
 228                         continue;
 229
 230                 sock_hold(sk);
 231                 goto exit;
 232         }
 233
 234         sk = NULL;
 235 exit:
 236         read_unlock_bh(&ping_table.lock);
 237
 238         return sk;
 239 }
 240
 241 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 242                                           kgid_t *high)
 243 {
 244         kgid_t *data = net->ipv4.ping_group_range.range;
 245         unsigned int seq;
 246
 247         do {
 248                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 249
 250                 *low = data[0];
 251                 *high = data[1];
 252         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 253 }
 254
 255
 256 int ping_init_sock(struct sock *sk)
 257 {
 258         struct net *net = sock_net(sk);
 259         kgid_t group = current_egid();
 260         struct group_info *group_info;
 261         int i, j, count;
 262         kgid_t low, high;
 263         int ret = 0;
 264
 265         if (sk->sk_family == AF_INET6)
 266                 sk->sk_ipv6only = 1;
 267
 268         inet_get_ping_group_range_net(net, &low, &high);
 269         if (gid_lte(low, group) && gid_lte(group, high))
 270                 return 0;
 271
 272         group_info = get_current_groups();
 273         count = group_info->ngroups;
 274         for (i = 0; i < group_info->nblocks; i++) {
 275                 int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
 276                 for (j = 0; j < cp_count; j++) {
 277                         kgid_t gid = group_info->blocks[i][j];
 278                         if (gid_lte(low, gid) && gid_lte(gid, high))
 279                                 goto out_release_group;
 280                 }
 281
 282                 count -= cp_count;
 283         }
 284
 285         ret = -EACCES;
 286
 287 out_release_group:
 288         put_group_info(group_info);
 289         return ret;
 290 }
 291 EXPORT_SYMBOL_GPL(ping_init_sock);
 292
 293 void ping_close(struct sock *sk, long timeout)
 294 {
 295         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 296                  inet_sk(sk), inet_sk(sk)->inet_num);
 297         pr_debug("isk->refcnt = %d\n", sk->sk_refcnt.counter);
 298
 299         sk_common_release(sk);
 300 }
 301 EXPORT_SYMBOL_GPL(ping_close);
 302
 303 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 304 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 305                                 struct sockaddr *uaddr, int addr_len) {
 306         struct net *net = sock_net(sk);
 307         if (sk->sk_family == AF_INET) {
 308                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 309                 int chk_addr_ret;
 310
 311                 if (addr_len < sizeof(*addr))
 312                         return -EINVAL;
 313
 314                 if (addr->sin_family != AF_INET &&
 315                     !(addr->sin_family == AF_UNSPEC &&
 316                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 317                         return -EAFNOSUPPORT;
 318
 319                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 320                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 321
 322                 chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
 323
 324                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 325                         chk_addr_ret = RTN_LOCAL;
 326
 327                 if ((net->ipv4.sysctl_ip_nonlocal_bind == 0 &&
 328                     isk->freebind == 0 && isk->transparent == 0 &&
 329                      chk_addr_ret != RTN_LOCAL) ||
 330                     chk_addr_ret == RTN_MULTICAST ||
 331                     chk_addr_ret == RTN_BROADCAST)
 332                         return -EADDRNOTAVAIL;
 333
 334 #if IS_ENABLED(CONFIG_IPV6)
 335         } else if (sk->sk_family == AF_INET6) {
 336                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 337                 int addr_type, scoped, has_addr;
 338                 struct net_device *dev = NULL;
 339
 340                 if (addr_len < sizeof(*addr))
 341                         return -EINVAL;
 342
 343                 if (addr->sin6_family != AF_INET6)
 344                         return -EAFNOSUPPORT;
 345
 346                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 347                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 348
 349                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 350                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 351                 if ((addr_type != IPV6_ADDR_ANY &&
 352                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 353                     (scoped && !addr->sin6_scope_id))
 354                         return -EINVAL;
 355
 356                 rcu_read_lock();
 357                 if (addr->sin6_scope_id) {
 358                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 359                         if (!dev) {
 360                                 rcu_read_unlock();
 361                                 return -ENODEV;
 362                         }
 363                 }
 364                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 365                                                     scoped);
 366                 rcu_read_unlock();
 367
 368                 if (!(net->ipv6.sysctl.ip_nonlocal_bind ||
 369                       isk->freebind || isk->transparent || has_addr ||
 370                       addr_type == IPV6_ADDR_ANY))
 371                         return -EADDRNOTAVAIL;
 372
 373                 if (scoped)
 374                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 375 #endif
 376         } else {
 377                 return -EAFNOSUPPORT;
 378         }
 379         return 0;
 380 }
 381
 382 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 383 {
 384         if (saddr->sa_family == AF_INET) {
 385                 struct inet_sock *isk = inet_sk(sk);
 386                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 387                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 388 #if IS_ENABLED(CONFIG_IPV6)
 389         } else if (saddr->sa_family == AF_INET6) {
 390                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 391                 struct ipv6_pinfo *np = inet6_sk(sk);
 392                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 393 #endif
 394         }
 395 }
 396
 397 static void ping_clear_saddr(struct sock *sk, int dif)
 398 {
 399         sk->sk_bound_dev_if = dif;
 400         if (sk->sk_family == AF_INET) {
 401                 struct inet_sock *isk = inet_sk(sk);
 402                 isk->inet_rcv_saddr = isk->inet_saddr = 0;
 403 #if IS_ENABLED(CONFIG_IPV6)
 404         } else if (sk->sk_family == AF_INET6) {
 405                 struct ipv6_pinfo *np = inet6_sk(sk);
 406                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 407                 memset(&np->saddr, 0, sizeof(np->saddr));
 408 #endif
 409         }
 410 }
 411 /*
 412  * We need our own bind because there are no privileged id's == local ports.
 413  * Moreover, we don't allow binding to multi- and broadcast addresses.
 414  */
 415
 416 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 417 {
 418         struct inet_sock *isk = inet_sk(sk);
 419         unsigned short snum;
 420         int err;
 421         int dif = sk->sk_bound_dev_if;
 422
 423         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 424         if (err)
 425                 return err;
 426
 427         lock_sock(sk);
 428
 429         err = -EINVAL;
 430         if (isk->inet_num != 0)
 431                 goto out;
 432
 433         err = -EADDRINUSE;
 434         ping_set_saddr(sk, uaddr);
 435         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 436         if (ping_get_port(sk, snum) != 0) {
 437                 ping_clear_saddr(sk, dif);
 438                 goto out;
 439         }
 440
 441         pr_debug("after bind(): num = %d, dif = %d\n",
 442                  (int)isk->inet_num,
 443                  (int)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_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0);
 480 }
 481
 482 /*
 483  * This routine is called by the ICMP module when it gets some
 484  * sort of error condition.
 485  */
 486
 487 void ping_err(struct sk_buff *skb, int offset, u32 info)
 488 {
 489         int family;
 490         struct icmphdr *icmph;
 491         struct inet_sock *inet_sock;
 492         int type;
 493         int code;
 494         struct net *net = dev_net(skb->dev);
 495         struct sock *sk;
 496         int harderr;
 497         int err;
 498
 499         if (skb->protocol == htons(ETH_P_IP)) {
 500                 family = AF_INET;
 501                 type = icmp_hdr(skb)->type;
 502                 code = icmp_hdr(skb)->code;
 503                 icmph = (struct icmphdr *)(skb->data + offset);
 504         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 505                 family = AF_INET6;
 506                 type = icmp6_hdr(skb)->icmp6_type;
 507                 code = icmp6_hdr(skb)->icmp6_code;
 508                 icmph = (struct icmphdr *) (skb->data + offset);
 509         } else {
 510                 BUG();
 511         }
 512
 513         /* We assume the packet has already been checked by icmp_unreach */
 514
 515         if (!ping_supported(family, icmph->type, icmph->code))
 516                 return;
 517
 518         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 519                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 520                  ntohs(icmph->un.echo.sequence));
 521
 522         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 523         if (!sk) {
 524                 pr_debug("no socket, dropping\n");
 525                 return; /* No socket for error */
 526         }
 527         pr_debug("err on socket %p\n", sk);
 528
 529         err = 0;
 530         harderr = 0;
 531         inet_sock = inet_sk(sk);
 532
 533         if (skb->protocol == htons(ETH_P_IP)) {
 534                 switch (type) {
 535                 default:
 536                 case ICMP_TIME_EXCEEDED:
 537                         err = EHOSTUNREACH;
 538                         break;
 539                 case ICMP_SOURCE_QUENCH:
 540                         /* This is not a real error but ping wants to see it.
 541                          * Report it with some fake errno.
 542                          */
 543                         err = EREMOTEIO;
 544                         break;
 545                 case ICMP_PARAMETERPROB:
 546                         err = EPROTO;
 547                         harderr = 1;
 548                         break;
 549                 case ICMP_DEST_UNREACH:
 550                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 551                                 ipv4_sk_update_pmtu(skb, sk, info);
 552                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 553                                         err = EMSGSIZE;
 554                                         harderr = 1;
 555                                         break;
 556                                 }
 557                                 goto out;
 558                         }
 559                         err = EHOSTUNREACH;
 560                         if (code <= NR_ICMP_UNREACH) {
 561                                 harderr = icmp_err_convert[code].fatal;
 562                                 err = icmp_err_convert[code].errno;
 563                         }
 564                         break;
 565                 case ICMP_REDIRECT:
 566                         /* See ICMP_SOURCE_QUENCH */
 567                         ipv4_sk_redirect(skb, sk);
 568                         err = EREMOTEIO;
 569                         break;
 570                 }
 571 #if IS_ENABLED(CONFIG_IPV6)
 572         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 573                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 574 #endif
 575         }
 576
 577         /*
 578          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 579          *      4.1.3.3.
 580          */
 581         if ((family == AF_INET && !inet_sock->recverr) ||
 582             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 583                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 584                         goto out;
 585         } else {
 586                 if (family == AF_INET) {
 587                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 588                                       info, (u8 *)icmph);
 589 #if IS_ENABLED(CONFIG_IPV6)
 590                 } else if (family == AF_INET6) {
 591                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 592                                                    info, (u8 *)icmph);
 593 #endif
 594                 }
 595         }
 596         sk->sk_err = err;
 597         sk->sk_error_report(sk);
 598 out:
 599         sock_put(sk);
 600 }
 601 EXPORT_SYMBOL_GPL(ping_err);
 602
 603 /*
 604  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 605  *      starting from the payload.
 606  */
 607
 608 int ping_getfrag(void *from, char *to,
 609                  int offset, int fraglen, int odd, struct sk_buff *skb)
 610 {
 611         struct pingfakehdr *pfh = (struct pingfakehdr *)from;
 612
 613         if (offset == 0) {
 614                 fraglen -= sizeof(struct icmphdr);
 615                 if (fraglen < 0)
 616                         BUG();
 617                 if (csum_and_copy_from_iter(to + sizeof(struct icmphdr),
 618                             fraglen, &pfh->wcheck,
 619                             &pfh->msg->msg_iter) != fraglen)
 620                         return -EFAULT;
 621         } else if (offset < sizeof(struct icmphdr)) {
 622                         BUG();
 623         } else {
 624                 if (csum_and_copy_from_iter(to, fraglen, &pfh->wcheck,
 625                                             &pfh->msg->msg_iter) != fraglen)
 626                         return -EFAULT;
 627         }
 628
 629 #if IS_ENABLED(CONFIG_IPV6)
 630         /* For IPv6, checksum each skb as we go along, as expected by
 631          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 632          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 633          */
 634         if (pfh->family == AF_INET6) {
 635                 skb->csum = pfh->wcheck;
 636                 skb->ip_summed = CHECKSUM_NONE;
 637                 pfh->wcheck = 0;
 638         }
 639 #endif
 640
 641         return 0;
 642 }
 643 EXPORT_SYMBOL_GPL(ping_getfrag);
 644
 645 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 646                                        struct flowi4 *fl4)
 647 {
 648         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 649
 650         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 651                 sizeof(struct icmphdr), pfh->wcheck);
 652         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 653         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 654         skb->ip_summed = CHECKSUM_NONE;
 655         return ip_push_pending_frames(sk, fl4);
 656 }
 657
 658 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 659                         void *user_icmph, size_t icmph_len) {
 660         u8 type, code;
 661
 662         if (len > 0xFFFF)
 663                 return -EMSGSIZE;
 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         ipc.sockc.tsflags = sk->sk_tsflags;
 741         ipc.addr = inet->inet_saddr;
 742         ipc.opt = NULL;
 743         ipc.oif = sk->sk_bound_dev_if;
 744         ipc.tx_flags = 0;
 745         ipc.ttl = 0;
 746         ipc.tos = -1;
 747
 748         if (msg->msg_controllen) {
 749                 err = ip_cmsg_send(sk, msg, &ipc, false);
 750                 if (unlikely(err)) {
 751                         kfree(ipc.opt);
 752                         return err;
 753                 }
 754                 if (ipc.opt)
 755                         free = 1;
 756         }
 757         if (!ipc.opt) {
 758                 struct ip_options_rcu *inet_opt;
 759
 760                 rcu_read_lock();
 761                 inet_opt = rcu_dereference(inet->inet_opt);
 762                 if (inet_opt) {
 763                         memcpy(&opt_copy, inet_opt,
 764                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 765                         ipc.opt = &opt_copy.opt;
 766                 }
 767                 rcu_read_unlock();
 768         }
 769
 770         sock_tx_timestamp(sk, ipc.sockc.tsflags, &ipc.tx_flags);
 771
 772         saddr = ipc.addr;
 773         ipc.addr = faddr = daddr;
 774
 775         if (ipc.opt && ipc.opt->opt.srr) {
 776                 if (!daddr)
 777                         return -EINVAL;
 778                 faddr = ipc.opt->opt.faddr;
 779         }
 780         tos = get_rttos(&ipc, inet);
 781         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 782             (msg->msg_flags & MSG_DONTROUTE) ||
 783             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 784                 tos |= RTO_ONLINK;
 785         }
 786
 787         if (ipv4_is_multicast(daddr)) {
 788                 if (!ipc.oif)
 789                         ipc.oif = inet->mc_index;
 790                 if (!saddr)
 791                         saddr = inet->mc_addr;
 792         } else if (!ipc.oif)
 793                 ipc.oif = inet->uc_index;
 794
 795         flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
 796                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 797                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0);
 798
 799         security_sk_classify_flow(sk, flowi4_to_flowi(&fl4));
 800         rt = ip_route_output_flow(net, &fl4, sk);
 801         if (IS_ERR(rt)) {
 802                 err = PTR_ERR(rt);
 803                 rt = NULL;
 804                 if (err == -ENETUNREACH)
 805                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 806                 goto out;
 807         }
 808
 809         err = -EACCES;
 810         if ((rt->rt_flags & RTCF_BROADCAST) &&
 811             !sock_flag(sk, SOCK_BROADCAST))
 812                 goto out;
 813
 814         if (msg->msg_flags & MSG_CONFIRM)
 815                 goto do_confirm;
 816 back_from_confirm:
 817
 818         if (!ipc.addr)
 819                 ipc.addr = fl4.daddr;
 820
 821         lock_sock(sk);
 822
 823         pfh.icmph.type = user_icmph.type; /* already checked */
 824         pfh.icmph.code = user_icmph.code; /* ditto */
 825         pfh.icmph.checksum = 0;
 826         pfh.icmph.un.echo.id = inet->inet_sport;
 827         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 828         pfh.msg = msg;
 829         pfh.wcheck = 0;
 830         pfh.family = AF_INET;
 831
 832         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 833                         0, &ipc, &rt, msg->msg_flags);
 834         if (err)
 835                 ip_flush_pending_frames(sk);
 836         else
 837                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 838         release_sock(sk);
 839
 840 out:
 841         ip_rt_put(rt);
 842         if (free)
 843                 kfree(ipc.opt);
 844         if (!err) {
 845                 icmp_out_count(sock_net(sk), user_icmph.type);
 846                 return len;
 847         }
 848         return err;
 849
 850 do_confirm:
 851         dst_confirm(&rt->dst);
 852         if (!(msg->msg_flags & MSG_PROBE) || len)
 853                 goto back_from_confirm;
 854         err = 0;
 855         goto out;
 856 }
 857
 858 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 859                  int flags, int *addr_len)
 860 {
 861         struct inet_sock *isk = inet_sk(sk);
 862         int family = sk->sk_family;
 863         struct sk_buff *skb;
 864         int copied, err;
 865
 866         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 867
 868         err = -EOPNOTSUPP;
 869         if (flags & MSG_OOB)
 870                 goto out;
 871
 872         if (flags & MSG_ERRQUEUE)
 873                 return inet_recv_error(sk, msg, len, addr_len);
 874
 875         skb = skb_recv_datagram(sk, flags, noblock, &err);
 876         if (!skb)
 877                 goto out;
 878
 879         copied = skb->len;
 880         if (copied > len) {
 881                 msg->msg_flags |= MSG_TRUNC;
 882                 copied = len;
 883         }
 884
 885         /* Don't bother checking the checksum */
 886         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 887         if (err)
 888                 goto done;
 889
 890         sock_recv_timestamp(msg, sk, skb);
 891
 892         /* Copy the address and add cmsg data. */
 893         if (family == AF_INET) {
 894                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 895
 896                 if (sin) {
 897                         sin->sin_family = AF_INET;
 898                         sin->sin_port = 0 /* skb->h.uh->source */;
 899                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 900                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 901                         *addr_len = sizeof(*sin);
 902                 }
 903
 904                 if (isk->cmsg_flags)
 905                         ip_cmsg_recv(msg, skb);
 906
 907 #if IS_ENABLED(CONFIG_IPV6)
 908         } else if (family == AF_INET6) {
 909                 struct ipv6_pinfo *np = inet6_sk(sk);
 910                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 911                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 912
 913                 if (sin6) {
 914                         sin6->sin6_family = AF_INET6;
 915                         sin6->sin6_port = 0;
 916                         sin6->sin6_addr = ip6->saddr;
 917                         sin6->sin6_flowinfo = 0;
 918                         if (np->sndflow)
 919                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 920                         sin6->sin6_scope_id =
 921                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 922                                                     inet6_iif(skb));
 923                         *addr_len = sizeof(*sin6);
 924                 }
 925
 926                 if (inet6_sk(sk)->rxopt.all)
 927                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 928                 if (skb->protocol == htons(ETH_P_IPV6) &&
 929                     inet6_sk(sk)->rxopt.all)
 930                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 931                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 932                         ip_cmsg_recv(msg, skb);
 933 #endif
 934         } else {
 935                 BUG();
 936         }
 937
 938         err = copied;
 939
 940 done:
 941         skb_free_datagram(sk, skb);
 942 out:
 943         pr_debug("ping_recvmsg -> %d\n", err);
 944         return err;
 945 }
 946 EXPORT_SYMBOL_GPL(ping_recvmsg);
 947
 948 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 949 {
 950         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 951                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 952         if (sock_queue_rcv_skb(sk, skb) < 0) {
 953                 kfree_skb(skb);
 954                 pr_debug("ping_queue_rcv_skb -> failed\n");
 955                 return -1;
 956         }
 957         return 0;
 958 }
 959 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 960
 961
 962 /*
 963  *      All we need to do is get the socket.
 964  */
 965
 966 bool ping_rcv(struct sk_buff *skb)
 967 {
 968         struct sock *sk;
 969         struct net *net = dev_net(skb->dev);
 970         struct icmphdr *icmph = icmp_hdr(skb);
 971
 972         /* We assume the packet has already been checked by icmp_rcv */
 973
 974         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 975                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 976
 977         /* Push ICMP header back */
 978         skb_push(skb, skb->data - (u8 *)icmph);
 979
 980         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 981         if (sk) {
 982                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 983
 984                 pr_debug("rcv on socket %p\n", sk);
 985                 if (skb2)
 986                         ping_queue_rcv_skb(sk, skb2);
 987                 sock_put(sk);
 988                 return true;
 989         }
 990         pr_debug("no socket, dropping\n");
 991
 992         return false;
 993 }
 994 EXPORT_SYMBOL_GPL(ping_rcv);
 995
 996 struct proto ping_prot = {
 997         .name =         "PING",
 998         .owner =        THIS_MODULE,
 999         .init =         ping_init_sock,
1000         .close =        ping_close,
1001         .connect =      ip4_datagram_connect,
1002         .disconnect =   udp_disconnect,
1003         .setsockopt =   ip_setsockopt,
1004         .getsockopt =   ip_getsockopt,
1005         .sendmsg =      ping_v4_sendmsg,
1006         .recvmsg =      ping_recvmsg,
1007         .bind =         ping_bind,
1008         .backlog_rcv =  ping_queue_rcv_skb,
1009         .release_cb =   ip4_datagram_release_cb,
1010         .hash =         ping_hash,
1011         .unhash =       ping_unhash,
1012         .get_port =     ping_get_port,
1013         .obj_size =     sizeof(struct inet_sock),
1014 };
1015 EXPORT_SYMBOL(ping_prot);
1016
1017 #ifdef CONFIG_PROC_FS
1018
1019 static struct sock *ping_get_first(struct seq_file *seq, int start)
1020 {
1021         struct sock *sk;
1022         struct ping_iter_state *state = seq->private;
1023         struct net *net = seq_file_net(seq);
1024
1025         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1026              ++state->bucket) {
1027                 struct hlist_nulls_node *node;
1028                 struct hlist_nulls_head *hslot;
1029
1030                 hslot = &ping_table.hash[state->bucket];
1031
1032                 if (hlist_nulls_empty(hslot))
1033                         continue;
1034
1035                 sk_nulls_for_each(sk, node, hslot) {
1036                         if (net_eq(sock_net(sk), net) &&
1037                             sk->sk_family == state->family)
1038                                 goto found;
1039                 }
1040         }
1041         sk = NULL;
1042 found:
1043         return sk;
1044 }
1045
1046 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1047 {
1048         struct ping_iter_state *state = seq->private;
1049         struct net *net = seq_file_net(seq);
1050
1051         do {
1052                 sk = sk_nulls_next(sk);
1053         } while (sk && (!net_eq(sock_net(sk), net)));
1054
1055         if (!sk)
1056                 return ping_get_first(seq, state->bucket + 1);
1057         return sk;
1058 }
1059
1060 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1061 {
1062         struct sock *sk = ping_get_first(seq, 0);
1063
1064         if (sk)
1065                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1066                         --pos;
1067         return pos ? NULL : sk;
1068 }
1069
1070 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1071         __acquires(ping_table.lock)
1072 {
1073         struct ping_iter_state *state = seq->private;
1074         state->bucket = 0;
1075         state->family = family;
1076
1077         read_lock_bh(&ping_table.lock);
1078
1079         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1080 }
1081 EXPORT_SYMBOL_GPL(ping_seq_start);
1082
1083 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1084 {
1085         return ping_seq_start(seq, pos, AF_INET);
1086 }
1087
1088 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1089 {
1090         struct sock *sk;
1091
1092         if (v == SEQ_START_TOKEN)
1093                 sk = ping_get_idx(seq, 0);
1094         else
1095                 sk = ping_get_next(seq, v);
1096
1097         ++*pos;
1098         return sk;
1099 }
1100 EXPORT_SYMBOL_GPL(ping_seq_next);
1101
1102 void ping_seq_stop(struct seq_file *seq, void *v)
1103         __releases(ping_table.lock)
1104 {
1105         read_unlock_bh(&ping_table.lock);
1106 }
1107 EXPORT_SYMBOL_GPL(ping_seq_stop);
1108
1109 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1110                 int bucket)
1111 {
1112         struct inet_sock *inet = inet_sk(sp);
1113         __be32 dest = inet->inet_daddr;
1114         __be32 src = inet->inet_rcv_saddr;
1115         __u16 destp = ntohs(inet->inet_dport);
1116         __u16 srcp = ntohs(inet->inet_sport);
1117
1118         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1119                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
1120                 bucket, src, srcp, dest, destp, sp->sk_state,
1121                 sk_wmem_alloc_get(sp),
1122                 sk_rmem_alloc_get(sp),
1123                 0, 0L, 0,
1124                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1125                 0, sock_i_ino(sp),
1126                 atomic_read(&sp->sk_refcnt), sp,
1127                 atomic_read(&sp->sk_drops));
1128 }
1129
1130 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1131 {
1132         seq_setwidth(seq, 127);
1133         if (v == SEQ_START_TOKEN)
1134                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1135                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1136                            "inode ref pointer drops");
1137         else {
1138                 struct ping_iter_state *state = seq->private;
1139
1140                 ping_v4_format_sock(v, seq, state->bucket);
1141         }
1142         seq_pad(seq, '\n');
1143         return 0;
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 }