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                 sock_put(sk);
 162                 isk->inet_num = 0;
 163                 isk->inet_sport = 0;
 164                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 165                 write_unlock_bh(&ping_table.lock);
 166         }
 167 }
 168 EXPORT_SYMBOL_GPL(ping_unhash);
 169
 170 static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 171 {
 172         struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
 173         struct sock *sk = NULL;
 174         struct inet_sock *isk;
 175         struct hlist_nulls_node *hnode;
 176         int dif = skb->dev->ifindex;
 177
 178         if (skb->protocol == htons(ETH_P_IP)) {
 179                 pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
 180                          (int)ident, &ip_hdr(skb)->daddr, dif);
 181 #if IS_ENABLED(CONFIG_IPV6)
 182         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 183                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 184                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
 185 #endif
 186         }
 187
 188         read_lock_bh(&ping_table.lock);
 189
 190         ping_portaddr_for_each_entry(sk, hnode, hslot) {
 191                 isk = inet_sk(sk);
 192
 193                 pr_debug("iterate\n");
 194                 if (isk->inet_num != ident)
 195                         continue;
 196
 197                 if (skb->protocol == htons(ETH_P_IP) &&
 198                     sk->sk_family == AF_INET) {
 199                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 200                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
 201                                  sk->sk_bound_dev_if);
 202
 203                         if (isk->inet_rcv_saddr &&
 204                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 205                                 continue;
 206 #if IS_ENABLED(CONFIG_IPV6)
 207                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
 208                            sk->sk_family == AF_INET6) {
 209
 210                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 211                                  (int) isk->inet_num,
 212                                  &sk->sk_v6_rcv_saddr,
 213                                  sk->sk_bound_dev_if);
 214
 215                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 216                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 217                                              &ipv6_hdr(skb)->daddr))
 218                                 continue;
 219 #endif
 220                 } else {
 221                         continue;
 222                 }
 223
 224                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
 225                         continue;
 226
 227                 sock_hold(sk);
 228                 goto exit;
 229         }
 230
 231         sk = NULL;
 232 exit:
 233         read_unlock_bh(&ping_table.lock);
 234
 235         return sk;
 236 }
 237
 238 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 239                                           kgid_t *high)
 240 {
 241         kgid_t *data = net->ipv4.ping_group_range.range;
 242         unsigned int seq;
 243
 244         do {
 245                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 246
 247                 *low = data[0];
 248                 *high = data[1];
 249         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 250 }
 251
 252
 253 int ping_init_sock(struct sock *sk)
 254 {
 255         struct net *net = sock_net(sk);
 256         kgid_t group = current_egid();
 257         struct group_info *group_info;
 258         int i, j, count;
 259         kgid_t low, high;
 260         int ret = 0;
 261
 262         if (sk->sk_family == AF_INET6)
 263                 sk->sk_ipv6only = 1;
 264
 265         inet_get_ping_group_range_net(net, &low, &high);
 266         if (gid_lte(low, group) && gid_lte(group, high))
 267                 return 0;
 268
 269         group_info = get_current_groups();
 270         count = group_info->ngroups;
 271         for (i = 0; i < group_info->nblocks; i++) {
 272                 int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
 273                 for (j = 0; j < cp_count; j++) {
 274                         kgid_t gid = group_info->blocks[i][j];
 275                         if (gid_lte(low, gid) && gid_lte(gid, high))
 276                                 goto out_release_group;
 277                 }
 278
 279                 count -= cp_count;
 280         }
 281
 282         ret = -EACCES;
 283
 284 out_release_group:
 285         put_group_info(group_info);
 286         return ret;
 287 }
 288 EXPORT_SYMBOL_GPL(ping_init_sock);
 289
 290 void ping_close(struct sock *sk, long timeout)
 291 {
 292         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 293                  inet_sk(sk), inet_sk(sk)->inet_num);
 294         pr_debug("isk->refcnt = %d\n", sk->sk_refcnt.counter);
 295
 296         sk_common_release(sk);
 297 }
 298 EXPORT_SYMBOL_GPL(ping_close);
 299
 300 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 301 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 302                                 struct sockaddr *uaddr, int addr_len) {
 303         struct net *net = sock_net(sk);
 304         if (sk->sk_family == AF_INET) {
 305                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 306                 int chk_addr_ret;
 307
 308                 if (addr_len < sizeof(*addr))
 309                         return -EINVAL;
 310
 311                 if (addr->sin_family != AF_INET &&
 312                     !(addr->sin_family == AF_UNSPEC &&
 313                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 314                         return -EAFNOSUPPORT;
 315
 316                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 317                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 318
 319                 chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
 320
 321                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 322                         chk_addr_ret = RTN_LOCAL;
 323
 324                 if ((net->ipv4.sysctl_ip_nonlocal_bind == 0 &&
 325                     isk->freebind == 0 && isk->transparent == 0 &&
 326                      chk_addr_ret != RTN_LOCAL) ||
 327                     chk_addr_ret == RTN_MULTICAST ||
 328                     chk_addr_ret == RTN_BROADCAST)
 329                         return -EADDRNOTAVAIL;
 330
 331 #if IS_ENABLED(CONFIG_IPV6)
 332         } else if (sk->sk_family == AF_INET6) {
 333                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 334                 int addr_type, scoped, has_addr;
 335                 struct net_device *dev = NULL;
 336
 337                 if (addr_len < sizeof(*addr))
 338                         return -EINVAL;
 339
 340                 if (addr->sin6_family != AF_INET6)
 341                         return -EAFNOSUPPORT;
 342
 343                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 344                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 345
 346                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 347                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 348                 if ((addr_type != IPV6_ADDR_ANY &&
 349                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 350                     (scoped && !addr->sin6_scope_id))
 351                         return -EINVAL;
 352
 353                 rcu_read_lock();
 354                 if (addr->sin6_scope_id) {
 355                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 356                         if (!dev) {
 357                                 rcu_read_unlock();
 358                                 return -ENODEV;
 359                         }
 360                 }
 361                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 362                                                     scoped);
 363                 rcu_read_unlock();
 364
 365                 if (!(isk->freebind || isk->transparent || has_addr ||
 366                       addr_type == IPV6_ADDR_ANY))
 367                         return -EADDRNOTAVAIL;
 368
 369                 if (scoped)
 370                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 371 #endif
 372         } else {
 373                 return -EAFNOSUPPORT;
 374         }
 375         return 0;
 376 }
 377
 378 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 379 {
 380         if (saddr->sa_family == AF_INET) {
 381                 struct inet_sock *isk = inet_sk(sk);
 382                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 383                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 384 #if IS_ENABLED(CONFIG_IPV6)
 385         } else if (saddr->sa_family == AF_INET6) {
 386                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 387                 struct ipv6_pinfo *np = inet6_sk(sk);
 388                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 389 #endif
 390         }
 391 }
 392
 393 static void ping_clear_saddr(struct sock *sk, int dif)
 394 {
 395         sk->sk_bound_dev_if = dif;
 396         if (sk->sk_family == AF_INET) {
 397                 struct inet_sock *isk = inet_sk(sk);
 398                 isk->inet_rcv_saddr = isk->inet_saddr = 0;
 399 #if IS_ENABLED(CONFIG_IPV6)
 400         } else if (sk->sk_family == AF_INET6) {
 401                 struct ipv6_pinfo *np = inet6_sk(sk);
 402                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 403                 memset(&np->saddr, 0, sizeof(np->saddr));
 404 #endif
 405         }
 406 }
 407 /*
 408  * We need our own bind because there are no privileged id's == local ports.
 409  * Moreover, we don't allow binding to multi- and broadcast addresses.
 410  */
 411
 412 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 413 {
 414         struct inet_sock *isk = inet_sk(sk);
 415         unsigned short snum;
 416         int err;
 417         int dif = sk->sk_bound_dev_if;
 418
 419         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 420         if (err)
 421                 return err;
 422
 423         lock_sock(sk);
 424
 425         err = -EINVAL;
 426         if (isk->inet_num != 0)
 427                 goto out;
 428
 429         err = -EADDRINUSE;
 430         ping_set_saddr(sk, uaddr);
 431         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 432         if (ping_get_port(sk, snum) != 0) {
 433                 ping_clear_saddr(sk, dif);
 434                 goto out;
 435         }
 436
 437         pr_debug("after bind(): num = %d, dif = %d\n",
 438                  (int)isk->inet_num,
 439                  (int)sk->sk_bound_dev_if);
 440
 441         err = 0;
 442         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 443                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 444 #if IS_ENABLED(CONFIG_IPV6)
 445         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 446                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 447 #endif
 448
 449         if (snum)
 450                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 451         isk->inet_sport = htons(isk->inet_num);
 452         isk->inet_daddr = 0;
 453         isk->inet_dport = 0;
 454
 455 #if IS_ENABLED(CONFIG_IPV6)
 456         if (sk->sk_family == AF_INET6)
 457                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 458 #endif
 459
 460         sk_dst_reset(sk);
 461 out:
 462         release_sock(sk);
 463         pr_debug("ping_v4_bind -> %d\n", err);
 464         return err;
 465 }
 466 EXPORT_SYMBOL_GPL(ping_bind);
 467
 468 /*
 469  * Is this a supported type of ICMP message?
 470  */
 471
 472 static inline int ping_supported(int family, int type, int code)
 473 {
 474         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 475                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0);
 476 }
 477
 478 /*
 479  * This routine is called by the ICMP module when it gets some
 480  * sort of error condition.
 481  */
 482
 483 void ping_err(struct sk_buff *skb, int offset, u32 info)
 484 {
 485         int family;
 486         struct icmphdr *icmph;
 487         struct inet_sock *inet_sock;
 488         int type;
 489         int code;
 490         struct net *net = dev_net(skb->dev);
 491         struct sock *sk;
 492         int harderr;
 493         int err;
 494
 495         if (skb->protocol == htons(ETH_P_IP)) {
 496                 family = AF_INET;
 497                 type = icmp_hdr(skb)->type;
 498                 code = icmp_hdr(skb)->code;
 499                 icmph = (struct icmphdr *)(skb->data + offset);
 500         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 501                 family = AF_INET6;
 502                 type = icmp6_hdr(skb)->icmp6_type;
 503                 code = icmp6_hdr(skb)->icmp6_code;
 504                 icmph = (struct icmphdr *) (skb->data + offset);
 505         } else {
 506                 BUG();
 507         }
 508
 509         /* We assume the packet has already been checked by icmp_unreach */
 510
 511         if (!ping_supported(family, icmph->type, icmph->code))
 512                 return;
 513
 514         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 515                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 516                  ntohs(icmph->un.echo.sequence));
 517
 518         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 519         if (!sk) {
 520                 pr_debug("no socket, dropping\n");
 521                 return; /* No socket for error */
 522         }
 523         pr_debug("err on socket %p\n", sk);
 524
 525         err = 0;
 526         harderr = 0;
 527         inet_sock = inet_sk(sk);
 528
 529         if (skb->protocol == htons(ETH_P_IP)) {
 530                 switch (type) {
 531                 default:
 532                 case ICMP_TIME_EXCEEDED:
 533                         err = EHOSTUNREACH;
 534                         break;
 535                 case ICMP_SOURCE_QUENCH:
 536                         /* This is not a real error but ping wants to see it.
 537                          * Report it with some fake errno.
 538                          */
 539                         err = EREMOTEIO;
 540                         break;
 541                 case ICMP_PARAMETERPROB:
 542                         err = EPROTO;
 543                         harderr = 1;
 544                         break;
 545                 case ICMP_DEST_UNREACH:
 546                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 547                                 ipv4_sk_update_pmtu(skb, sk, info);
 548                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 549                                         err = EMSGSIZE;
 550                                         harderr = 1;
 551                                         break;
 552                                 }
 553                                 goto out;
 554                         }
 555                         err = EHOSTUNREACH;
 556                         if (code <= NR_ICMP_UNREACH) {
 557                                 harderr = icmp_err_convert[code].fatal;
 558                                 err = icmp_err_convert[code].errno;
 559                         }
 560                         break;
 561                 case ICMP_REDIRECT:
 562                         /* See ICMP_SOURCE_QUENCH */
 563                         ipv4_sk_redirect(skb, sk);
 564                         err = EREMOTEIO;
 565                         break;
 566                 }
 567 #if IS_ENABLED(CONFIG_IPV6)
 568         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 569                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 570 #endif
 571         }
 572
 573         /*
 574          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 575          *      4.1.3.3.
 576          */
 577         if ((family == AF_INET && !inet_sock->recverr) ||
 578             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 579                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 580                         goto out;
 581         } else {
 582                 if (family == AF_INET) {
 583                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 584                                       info, (u8 *)icmph);
 585 #if IS_ENABLED(CONFIG_IPV6)
 586                 } else if (family == AF_INET6) {
 587                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 588                                                    info, (u8 *)icmph);
 589 #endif
 590                 }
 591         }
 592         sk->sk_err = err;
 593         sk->sk_error_report(sk);
 594 out:
 595         sock_put(sk);
 596 }
 597 EXPORT_SYMBOL_GPL(ping_err);
 598
 599 /*
 600  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 601  *      starting from the payload.
 602  */
 603
 604 int ping_getfrag(void *from, char *to,
 605                  int offset, int fraglen, int odd, struct sk_buff *skb)
 606 {
 607         struct pingfakehdr *pfh = (struct pingfakehdr *)from;
 608
 609         if (offset == 0) {
 610                 fraglen -= sizeof(struct icmphdr);
 611                 if (fraglen < 0)
 612                         BUG();
 613                 if (csum_and_copy_from_iter(to + sizeof(struct icmphdr),
 614                             fraglen, &pfh->wcheck,
 615                             &pfh->msg->msg_iter) != fraglen)
 616                         return -EFAULT;
 617         } else if (offset < sizeof(struct icmphdr)) {
 618                         BUG();
 619         } else {
 620                 if (csum_and_copy_from_iter(to, fraglen, &pfh->wcheck,
 621                                             &pfh->msg->msg_iter) != fraglen)
 622                         return -EFAULT;
 623         }
 624
 625 #if IS_ENABLED(CONFIG_IPV6)
 626         /* For IPv6, checksum each skb as we go along, as expected by
 627          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 628          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 629          */
 630         if (pfh->family == AF_INET6) {
 631                 skb->csum = pfh->wcheck;
 632                 skb->ip_summed = CHECKSUM_NONE;
 633                 pfh->wcheck = 0;
 634         }
 635 #endif
 636
 637         return 0;
 638 }
 639 EXPORT_SYMBOL_GPL(ping_getfrag);
 640
 641 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 642                                        struct flowi4 *fl4)
 643 {
 644         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 645
 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         /*
 662          *      Check the flags.
 663          */
 664
 665         /* Mirror BSD error message compatibility */
 666         if (msg->msg_flags & MSG_OOB)
 667                 return -EOPNOTSUPP;
 668
 669         /*
 670          *      Fetch the ICMP header provided by the userland.
 671          *      iovec is modified! The ICMP header is consumed.
 672          */
 673         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 674                 return -EFAULT;
 675
 676         if (family == AF_INET) {
 677                 type = ((struct icmphdr *) user_icmph)->type;
 678                 code = ((struct icmphdr *) user_icmph)->code;
 679 #if IS_ENABLED(CONFIG_IPV6)
 680         } else if (family == AF_INET6) {
 681                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 682                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 683 #endif
 684         } else {
 685                 BUG();
 686         }
 687
 688         if (!ping_supported(family, type, code))
 689                 return -EINVAL;
 690
 691         return 0;
 692 }
 693 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 694
 695 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 696 {
 697         struct net *net = sock_net(sk);
 698         struct flowi4 fl4;
 699         struct inet_sock *inet = inet_sk(sk);
 700         struct ipcm_cookie ipc;
 701         struct icmphdr user_icmph;
 702         struct pingfakehdr pfh;
 703         struct rtable *rt = NULL;
 704         struct ip_options_data opt_copy;
 705         int free = 0;
 706         __be32 saddr, daddr, faddr;
 707         u8  tos;
 708         int err;
 709
 710         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 711
 712         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 713                                   sizeof(user_icmph));
 714         if (err)
 715                 return err;
 716
 717         /*
 718          *      Get and verify the address.
 719          */
 720
 721         if (msg->msg_name) {
 722                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 723                 if (msg->msg_namelen < sizeof(*usin))
 724                         return -EINVAL;
 725                 if (usin->sin_family != AF_INET)
 726                         return -EAFNOSUPPORT;
 727                 daddr = usin->sin_addr.s_addr;
 728                 /* no remote port */
 729         } else {
 730                 if (sk->sk_state != TCP_ESTABLISHED)
 731                         return -EDESTADDRREQ;
 732                 daddr = inet->inet_daddr;
 733                 /* no remote port */
 734         }
 735
 736         ipc.addr = inet->inet_saddr;
 737         ipc.opt = NULL;
 738         ipc.oif = sk->sk_bound_dev_if;
 739         ipc.tx_flags = 0;
 740         ipc.ttl = 0;
 741         ipc.tos = -1;
 742
 743         sock_tx_timestamp(sk, &ipc.tx_flags);
 744
 745         if (msg->msg_controllen) {
 746                 err = ip_cmsg_send(sock_net(sk), msg, &ipc, false);
 747                 if (err)
 748                         return err;
 749                 if (ipc.opt)
 750                         free = 1;
 751         }
 752         if (!ipc.opt) {
 753                 struct ip_options_rcu *inet_opt;
 754
 755                 rcu_read_lock();
 756                 inet_opt = rcu_dereference(inet->inet_opt);
 757                 if (inet_opt) {
 758                         memcpy(&opt_copy, inet_opt,
 759                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 760                         ipc.opt = &opt_copy.opt;
 761                 }
 762                 rcu_read_unlock();
 763         }
 764
 765         saddr = ipc.addr;
 766         ipc.addr = faddr = daddr;
 767
 768         if (ipc.opt && ipc.opt->opt.srr) {
 769                 if (!daddr)
 770                         return -EINVAL;
 771                 faddr = ipc.opt->opt.faddr;
 772         }
 773         tos = get_rttos(&ipc, inet);
 774         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 775             (msg->msg_flags & MSG_DONTROUTE) ||
 776             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 777                 tos |= RTO_ONLINK;
 778         }
 779
 780         if (ipv4_is_multicast(daddr)) {
 781                 if (!ipc.oif)
 782                         ipc.oif = inet->mc_index;
 783                 if (!saddr)
 784                         saddr = inet->mc_addr;
 785         } else if (!ipc.oif)
 786                 ipc.oif = inet->uc_index;
 787
 788         flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
 789                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 790                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0);
 791
 792         security_sk_classify_flow(sk, flowi4_to_flowi(&fl4));
 793         rt = ip_route_output_flow(net, &fl4, sk);
 794         if (IS_ERR(rt)) {
 795                 err = PTR_ERR(rt);
 796                 rt = NULL;
 797                 if (err == -ENETUNREACH)
 798                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 799                 goto out;
 800         }
 801
 802         err = -EACCES;
 803         if ((rt->rt_flags & RTCF_BROADCAST) &&
 804             !sock_flag(sk, SOCK_BROADCAST))
 805                 goto out;
 806
 807         if (msg->msg_flags & MSG_CONFIRM)
 808                 goto do_confirm;
 809 back_from_confirm:
 810
 811         if (!ipc.addr)
 812                 ipc.addr = fl4.daddr;
 813
 814         lock_sock(sk);
 815
 816         pfh.icmph.type = user_icmph.type; /* already checked */
 817         pfh.icmph.code = user_icmph.code; /* ditto */
 818         pfh.icmph.checksum = 0;
 819         pfh.icmph.un.echo.id = inet->inet_sport;
 820         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 821         pfh.msg = msg;
 822         pfh.wcheck = 0;
 823         pfh.family = AF_INET;
 824
 825         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 826                         0, &ipc, &rt, msg->msg_flags);
 827         if (err)
 828                 ip_flush_pending_frames(sk);
 829         else
 830                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 831         release_sock(sk);
 832
 833 out:
 834         ip_rt_put(rt);
 835         if (free)
 836                 kfree(ipc.opt);
 837         if (!err) {
 838                 icmp_out_count(sock_net(sk), user_icmph.type);
 839                 return len;
 840         }
 841         return err;
 842
 843 do_confirm:
 844         dst_confirm(&rt->dst);
 845         if (!(msg->msg_flags & MSG_PROBE) || len)
 846                 goto back_from_confirm;
 847         err = 0;
 848         goto out;
 849 }
 850
 851 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 852                  int flags, int *addr_len)
 853 {
 854         struct inet_sock *isk = inet_sk(sk);
 855         int family = sk->sk_family;
 856         struct sk_buff *skb;
 857         int copied, err;
 858
 859         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 860
 861         err = -EOPNOTSUPP;
 862         if (flags & MSG_OOB)
 863                 goto out;
 864
 865         if (flags & MSG_ERRQUEUE)
 866                 return inet_recv_error(sk, msg, len, addr_len);
 867
 868         skb = skb_recv_datagram(sk, flags, noblock, &err);
 869         if (!skb)
 870                 goto out;
 871
 872         copied = skb->len;
 873         if (copied > len) {
 874                 msg->msg_flags |= MSG_TRUNC;
 875                 copied = len;
 876         }
 877
 878         /* Don't bother checking the checksum */
 879         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 880         if (err)
 881                 goto done;
 882
 883         sock_recv_timestamp(msg, sk, skb);
 884
 885         /* Copy the address and add cmsg data. */
 886         if (family == AF_INET) {
 887                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 888
 889                 if (sin) {
 890                         sin->sin_family = AF_INET;
 891                         sin->sin_port = 0 /* skb->h.uh->source */;
 892                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 893                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 894                         *addr_len = sizeof(*sin);
 895                 }
 896
 897                 if (isk->cmsg_flags)
 898                         ip_cmsg_recv(msg, skb);
 899
 900 #if IS_ENABLED(CONFIG_IPV6)
 901         } else if (family == AF_INET6) {
 902                 struct ipv6_pinfo *np = inet6_sk(sk);
 903                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 904                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 905
 906                 if (sin6) {
 907                         sin6->sin6_family = AF_INET6;
 908                         sin6->sin6_port = 0;
 909                         sin6->sin6_addr = ip6->saddr;
 910                         sin6->sin6_flowinfo = 0;
 911                         if (np->sndflow)
 912                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 913                         sin6->sin6_scope_id =
 914                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 915                                                     inet6_iif(skb));
 916                         *addr_len = sizeof(*sin6);
 917                 }
 918
 919                 if (inet6_sk(sk)->rxopt.all)
 920                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 921                 if (skb->protocol == htons(ETH_P_IPV6) &&
 922                     inet6_sk(sk)->rxopt.all)
 923                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 924                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 925                         ip_cmsg_recv(msg, skb);
 926 #endif
 927         } else {
 928                 BUG();
 929         }
 930
 931         err = copied;
 932
 933 done:
 934         skb_free_datagram(sk, skb);
 935 out:
 936         pr_debug("ping_recvmsg -> %d\n", err);
 937         return err;
 938 }
 939 EXPORT_SYMBOL_GPL(ping_recvmsg);
 940
 941 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 942 {
 943         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 944                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 945         if (sock_queue_rcv_skb(sk, skb) < 0) {
 946                 kfree_skb(skb);
 947                 pr_debug("ping_queue_rcv_skb -> failed\n");
 948                 return -1;
 949         }
 950         return 0;
 951 }
 952 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 953
 954
 955 /*
 956  *      All we need to do is get the socket.
 957  */
 958
 959 bool ping_rcv(struct sk_buff *skb)
 960 {
 961         struct sock *sk;
 962         struct net *net = dev_net(skb->dev);
 963         struct icmphdr *icmph = icmp_hdr(skb);
 964
 965         /* We assume the packet has already been checked by icmp_rcv */
 966
 967         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 968                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 969
 970         /* Push ICMP header back */
 971         skb_push(skb, skb->data - (u8 *)icmph);
 972
 973         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 974         if (sk) {
 975                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 976
 977                 pr_debug("rcv on socket %p\n", sk);
 978                 if (skb2)
 979                         ping_queue_rcv_skb(sk, skb2);
 980                 sock_put(sk);
 981                 return true;
 982         }
 983         pr_debug("no socket, dropping\n");
 984
 985         return false;
 986 }
 987 EXPORT_SYMBOL_GPL(ping_rcv);
 988
 989 struct proto ping_prot = {
 990         .name =         "PING",
 991         .owner =        THIS_MODULE,
 992         .init =         ping_init_sock,
 993         .close =        ping_close,
 994         .connect =      ip4_datagram_connect,
 995         .disconnect =   udp_disconnect,
 996         .setsockopt =   ip_setsockopt,
 997         .getsockopt =   ip_getsockopt,
 998         .sendmsg =      ping_v4_sendmsg,
 999         .recvmsg =      ping_recvmsg,
1000         .bind =         ping_bind,
1001         .backlog_rcv =  ping_queue_rcv_skb,
1002         .release_cb =   ip4_datagram_release_cb,
1003         .hash =         ping_hash,
1004         .unhash =       ping_unhash,
1005         .get_port =     ping_get_port,
1006         .obj_size =     sizeof(struct inet_sock),
1007 };
1008 EXPORT_SYMBOL(ping_prot);
1009
1010 #ifdef CONFIG_PROC_FS
1011
1012 static struct sock *ping_get_first(struct seq_file *seq, int start)
1013 {
1014         struct sock *sk;
1015         struct ping_iter_state *state = seq->private;
1016         struct net *net = seq_file_net(seq);
1017
1018         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1019              ++state->bucket) {
1020                 struct hlist_nulls_node *node;
1021                 struct hlist_nulls_head *hslot;
1022
1023                 hslot = &ping_table.hash[state->bucket];
1024
1025                 if (hlist_nulls_empty(hslot))
1026                         continue;
1027
1028                 sk_nulls_for_each(sk, node, hslot) {
1029                         if (net_eq(sock_net(sk), net) &&
1030                             sk->sk_family == state->family)
1031                                 goto found;
1032                 }
1033         }
1034         sk = NULL;
1035 found:
1036         return sk;
1037 }
1038
1039 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1040 {
1041         struct ping_iter_state *state = seq->private;
1042         struct net *net = seq_file_net(seq);
1043
1044         do {
1045                 sk = sk_nulls_next(sk);
1046         } while (sk && (!net_eq(sock_net(sk), net)));
1047
1048         if (!sk)
1049                 return ping_get_first(seq, state->bucket + 1);
1050         return sk;
1051 }
1052
1053 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1054 {
1055         struct sock *sk = ping_get_first(seq, 0);
1056
1057         if (sk)
1058                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1059                         --pos;
1060         return pos ? NULL : sk;
1061 }
1062
1063 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1064 {
1065         struct ping_iter_state *state = seq->private;
1066         state->bucket = 0;
1067         state->family = family;
1068
1069         read_lock_bh(&ping_table.lock);
1070
1071         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1072 }
1073 EXPORT_SYMBOL_GPL(ping_seq_start);
1074
1075 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1076 {
1077         return ping_seq_start(seq, pos, AF_INET);
1078 }
1079
1080 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1081 {
1082         struct sock *sk;
1083
1084         if (v == SEQ_START_TOKEN)
1085                 sk = ping_get_idx(seq, 0);
1086         else
1087                 sk = ping_get_next(seq, v);
1088
1089         ++*pos;
1090         return sk;
1091 }
1092 EXPORT_SYMBOL_GPL(ping_seq_next);
1093
1094 void ping_seq_stop(struct seq_file *seq, void *v)
1095 {
1096         read_unlock_bh(&ping_table.lock);
1097 }
1098 EXPORT_SYMBOL_GPL(ping_seq_stop);
1099
1100 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1101                 int bucket)
1102 {
1103         struct inet_sock *inet = inet_sk(sp);
1104         __be32 dest = inet->inet_daddr;
1105         __be32 src = inet->inet_rcv_saddr;
1106         __u16 destp = ntohs(inet->inet_dport);
1107         __u16 srcp = ntohs(inet->inet_sport);
1108
1109         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1110                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
1111                 bucket, src, srcp, dest, destp, sp->sk_state,
1112                 sk_wmem_alloc_get(sp),
1113                 sk_rmem_alloc_get(sp),
1114                 0, 0L, 0,
1115                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1116                 0, sock_i_ino(sp),
1117                 atomic_read(&sp->sk_refcnt), sp,
1118                 atomic_read(&sp->sk_drops));
1119 }
1120
1121 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1122 {
1123         seq_setwidth(seq, 127);
1124         if (v == SEQ_START_TOKEN)
1125                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1126                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1127                            "inode ref pointer drops");
1128         else {
1129                 struct ping_iter_state *state = seq->private;
1130
1131                 ping_v4_format_sock(v, seq, state->bucket);
1132         }
1133         seq_pad(seq, '\n');
1134         return 0;
1135 }
1136
1137 static const struct seq_operations ping_v4_seq_ops = {
1138         .show           = ping_v4_seq_show,
1139         .start          = ping_v4_seq_start,
1140         .next           = ping_seq_next,
1141         .stop           = ping_seq_stop,
1142 };
1143
1144 static int ping_seq_open(struct inode *inode, struct file *file)
1145 {
1146         struct ping_seq_afinfo *afinfo = PDE_DATA(inode);
1147         return seq_open_net(inode, file, &afinfo->seq_ops,
1148                            sizeof(struct ping_iter_state));
1149 }
1150
1151 const struct file_operations ping_seq_fops = {
1152         .open           = ping_seq_open,
1153         .read           = seq_read,
1154         .llseek         = seq_lseek,
1155         .release        = seq_release_net,
1156 };
1157 EXPORT_SYMBOL_GPL(ping_seq_fops);
1158
1159 static struct ping_seq_afinfo ping_v4_seq_afinfo = {
1160         .name           = "icmp",
1161         .family         = AF_INET,
1162         .seq_fops       = &ping_seq_fops,
1163         .seq_ops        = {
1164                 .start          = ping_v4_seq_start,
1165                 .show           = ping_v4_seq_show,
1166                 .next           = ping_seq_next,
1167                 .stop           = ping_seq_stop,
1168         },
1169 };
1170
1171 int ping_proc_register(struct net *net, struct ping_seq_afinfo *afinfo)
1172 {
1173         struct proc_dir_entry *p;
1174         p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
1175                              afinfo->seq_fops, afinfo);
1176         if (!p)
1177                 return -ENOMEM;
1178         return 0;
1179 }
1180 EXPORT_SYMBOL_GPL(ping_proc_register);
1181
1182 void ping_proc_unregister(struct net *net, struct ping_seq_afinfo *afinfo)
1183 {
1184         remove_proc_entry(afinfo->name, net->proc_net);
1185 }
1186 EXPORT_SYMBOL_GPL(ping_proc_unregister);
1187
1188 static int __net_init ping_v4_proc_init_net(struct net *net)
1189 {
1190         return ping_proc_register(net, &ping_v4_seq_afinfo);
1191 }
1192
1193 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1194 {
1195         ping_proc_unregister(net, &ping_v4_seq_afinfo);
1196 }
1197
1198 static struct pernet_operations ping_v4_net_ops = {
1199         .init = ping_v4_proc_init_net,
1200         .exit = ping_v4_proc_exit_net,
1201 };
1202
1203 int __init ping_proc_init(void)
1204 {
1205         return register_pernet_subsys(&ping_v4_net_ops);
1206 }
1207
1208 void ping_proc_exit(void)
1209 {
1210         unregister_pernet_subsys(&ping_v4_net_ops);
1211 }
1212
1213 #endif
1214
1215 void __init ping_init(void)
1216 {
1217         int i;
1218
1219         for (i = 0; i < PING_HTABLE_SIZE; i++)
1220                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1221         rwlock_init(&ping_table.lock);
1222 }