net/ipv4/ping.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4  *              operating system.  INET is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              "Ping" sockets
   8  *
   9  * Based on ipv4/udp.c code.
  10  *
  11  * Authors:     Vasiliy Kulikov / Openwall (for Linux 2.6),
  12  *              Pavel Kankovsky (for Linux 2.4.32)
  13  *
  14  * Pavel gave all rights to bugs to Vasiliy,
  15  * none of the bugs are Pavel's now.
  16  */
  17
  18 #include <linux/uaccess.h>
  19 #include <linux/types.h>
  20 #include <linux/fcntl.h>
  21 #include <linux/socket.h>
  22 #include <linux/sockios.h>
  23 #include <linux/in.h>
  24 #include <linux/errno.h>
  25 #include <linux/timer.h>
  26 #include <linux/mm.h>
  27 #include <linux/inet.h>
  28 #include <linux/netdevice.h>
  29 #include <net/snmp.h>
  30 #include <net/ip.h>
  31 #include <net/icmp.h>
  32 #include <net/protocol.h>
  33 #include <linux/skbuff.h>
  34 #include <linux/proc_fs.h>
  35 #include <linux/export.h>
  36 #include <net/sock.h>
  37 #include <net/ping.h>
  38 #include <net/udp.h>
  39 #include <net/route.h>
  40 #include <net/inet_common.h>
  41 #include <net/checksum.h>
  42
  43 #if IS_ENABLED(CONFIG_IPV6)
  44 #include <linux/in6.h>
  45 #include <linux/icmpv6.h>
  46 #include <net/addrconf.h>
  47 #include <net/ipv6.h>
  48 #include <net/transp_v6.h>
  49 #endif
  50
  51 struct ping_table {
  52         struct hlist_nulls_head hash[PING_HTABLE_SIZE];
  53         rwlock_t                lock;
  54 };
  55
  56 static struct ping_table ping_table;
  57 struct pingv6_ops pingv6_ops;
  58 EXPORT_SYMBOL_GPL(pingv6_ops);
  59
  60 static u16 ping_port_rover;
  61
  62 static inline u32 ping_hashfn(const struct net *net, u32 num, u32 mask)
  63 {
  64         u32 res = (num + net_hash_mix(net)) & mask;
  65
  66         pr_debug("hash(%u) = %u\n", num, res);
  67         return res;
  68 }
  69 EXPORT_SYMBOL_GPL(ping_hash);
  70
  71 static inline struct hlist_nulls_head *ping_hashslot(struct ping_table *table,
  72                                              struct net *net, unsigned int num)
  73 {
  74         return &table->hash[ping_hashfn(net, num, PING_HTABLE_MASK)];
  75 }
  76
  77 int ping_get_port(struct sock *sk, unsigned short ident)
  78 {
  79         struct hlist_nulls_node *node;
  80         struct hlist_nulls_head *hlist;
  81         struct inet_sock *isk, *isk2;
  82         struct sock *sk2 = NULL;
  83
  84         isk = inet_sk(sk);
  85         write_lock_bh(&ping_table.lock);
  86         if (ident == 0) {
  87                 u32 i;
  88                 u16 result = ping_port_rover + 1;
  89
  90                 for (i = 0; i < (1L << 16); i++, result++) {
  91                         if (!result)
  92                                 result++; /* avoid zero */
  93                         hlist = ping_hashslot(&ping_table, sock_net(sk),
  94                                             result);
  95                         ping_portaddr_for_each_entry(sk2, node, hlist) {
  96                                 isk2 = inet_sk(sk2);
  97
  98                                 if (isk2->inet_num == result)
  99                                         goto next_port;
 100                         }
 101
 102                         /* found */
 103                         ping_port_rover = ident = result;
 104                         break;
 105 next_port:
 106                         ;
 107                 }
 108                 if (i >= (1L << 16))
 109                         goto fail;
 110         } else {
 111                 hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
 112                 ping_portaddr_for_each_entry(sk2, node, hlist) {
 113                         isk2 = inet_sk(sk2);
 114
 115                         /* BUG? Why is this reuse and not reuseaddr? ping.c
 116                          * doesn't turn off SO_REUSEADDR, and it doesn't expect
 117                          * that other ping processes can steal its packets.
 118                          */
 119                         if ((isk2->inet_num == ident) &&
 120                             (sk2 != sk) &&
 121                             (!sk2->sk_reuse || !sk->sk_reuse))
 122                                 goto fail;
 123                 }
 124         }
 125
 126         pr_debug("found port/ident = %d\n", ident);
 127         isk->inet_num = ident;
 128         if (sk_unhashed(sk)) {
 129                 pr_debug("was not hashed\n");
 130                 sock_hold(sk);
 131                 hlist_nulls_add_head(&sk->sk_nulls_node, hlist);
 132                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 133         }
 134         write_unlock_bh(&ping_table.lock);
 135         return 0;
 136
 137 fail:
 138         write_unlock_bh(&ping_table.lock);
 139         return 1;
 140 }
 141 EXPORT_SYMBOL_GPL(ping_get_port);
 142
 143 int ping_hash(struct sock *sk)
 144 {
 145         pr_debug("ping_hash(sk->port=%u)\n", inet_sk(sk)->inet_num);
 146         BUG(); /* "Please do not press this button again." */
 147
 148         return 0;
 149 }
 150
 151 void ping_unhash(struct sock *sk)
 152 {
 153         struct inet_sock *isk = inet_sk(sk);
 154
 155         pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
 156         write_lock_bh(&ping_table.lock);
 157         if (sk_hashed(sk)) {
 158                 hlist_nulls_del(&sk->sk_nulls_node);
 159                 sk_nulls_node_init(&sk->sk_nulls_node);
 160                 sock_put(sk);
 161                 isk->inet_num = 0;
 162                 isk->inet_sport = 0;
 163                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 164         }
 165         write_unlock_bh(&ping_table.lock);
 166 }
 167 EXPORT_SYMBOL_GPL(ping_unhash);
 168
 169 static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 170 {
 171         struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
 172         struct sock *sk = NULL;
 173         struct inet_sock *isk;
 174         struct hlist_nulls_node *hnode;
 175         int dif, sdif;
 176
 177         if (skb->protocol == htons(ETH_P_IP)) {
 178                 dif = inet_iif(skb);
 179                 sdif = inet_sdif(skb);
 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                 dif = inet6_iif(skb);
 185                 sdif = inet6_sdif(skb);
 186                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 187                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
 188 #endif
 189         } else {
 190                 pr_err("ping: protocol(%x) is not supported\n", ntohs(skb->protocol));
 191                 return NULL;
 192         }
 193
 194         read_lock_bh(&ping_table.lock);
 195
 196         ping_portaddr_for_each_entry(sk, hnode, hslot) {
 197                 isk = inet_sk(sk);
 198
 199                 pr_debug("iterate\n");
 200                 if (isk->inet_num != ident)
 201                         continue;
 202
 203                 if (skb->protocol == htons(ETH_P_IP) &&
 204                     sk->sk_family == AF_INET) {
 205                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 206                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
 207                                  sk->sk_bound_dev_if);
 208
 209                         if (isk->inet_rcv_saddr &&
 210                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 211                                 continue;
 212 #if IS_ENABLED(CONFIG_IPV6)
 213                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
 214                            sk->sk_family == AF_INET6) {
 215
 216                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 217                                  (int) isk->inet_num,
 218                                  &sk->sk_v6_rcv_saddr,
 219                                  sk->sk_bound_dev_if);
 220
 221                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 222                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 223                                              &ipv6_hdr(skb)->daddr))
 224                                 continue;
 225 #endif
 226                 } else {
 227                         continue;
 228                 }
 229
 230                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif &&
 231                     sk->sk_bound_dev_if != sdif)
 232                         continue;
 233
 234                 sock_hold(sk);
 235                 goto exit;
 236         }
 237
 238         sk = NULL;
 239 exit:
 240         read_unlock_bh(&ping_table.lock);
 241
 242         return sk;
 243 }
 244
 245 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 246                                           kgid_t *high)
 247 {
 248         kgid_t *data = net->ipv4.ping_group_range.range;
 249         unsigned int seq;
 250
 251         do {
 252                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 253
 254                 *low = data[0];
 255                 *high = data[1];
 256         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 257 }
 258
 259
 260 int ping_init_sock(struct sock *sk)
 261 {
 262         struct net *net = sock_net(sk);
 263         kgid_t group = current_egid();
 264         struct group_info *group_info;
 265         int i;
 266         kgid_t low, high;
 267         int ret = 0;
 268
 269         if (sk->sk_family == AF_INET6)
 270                 sk->sk_ipv6only = 1;
 271
 272         inet_get_ping_group_range_net(net, &low, &high);
 273         if (gid_lte(low, group) && gid_lte(group, high))
 274                 return 0;
 275
 276         group_info = get_current_groups();
 277         for (i = 0; i < group_info->ngroups; i++) {
 278                 kgid_t gid = group_info->gid[i];
 279
 280                 if (gid_lte(low, gid) && gid_lte(gid, high))
 281                         goto out_release_group;
 282         }
 283
 284         ret = -EACCES;
 285
 286 out_release_group:
 287         put_group_info(group_info);
 288         return ret;
 289 }
 290 EXPORT_SYMBOL_GPL(ping_init_sock);
 291
 292 void ping_close(struct sock *sk, long timeout)
 293 {
 294         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 295                  inet_sk(sk), inet_sk(sk)->inet_num);
 296         pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
 297
 298         sk_common_release(sk);
 299 }
 300 EXPORT_SYMBOL_GPL(ping_close);
 301
 302 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 303 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 304                                 struct sockaddr *uaddr, int addr_len)
 305 {
 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 (!inet_addr_valid_or_nonlocal(net, inet_sk(sk),
 325                                                  addr->sin_addr.s_addr,
 326                                                  chk_addr_ret))
 327                         return -EADDRNOTAVAIL;
 328
 329 #if IS_ENABLED(CONFIG_IPV6)
 330         } else if (sk->sk_family == AF_INET6) {
 331                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 332                 int addr_type, scoped, has_addr;
 333                 struct net_device *dev = NULL;
 334
 335                 if (addr_len < sizeof(*addr))
 336                         return -EINVAL;
 337
 338                 if (addr->sin6_family != AF_INET6)
 339                         return -EAFNOSUPPORT;
 340
 341                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 342                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 343
 344                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 345                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 346                 if ((addr_type != IPV6_ADDR_ANY &&
 347                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 348                     (scoped && !addr->sin6_scope_id))
 349                         return -EINVAL;
 350
 351                 rcu_read_lock();
 352                 if (addr->sin6_scope_id) {
 353                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 354                         if (!dev) {
 355                                 rcu_read_unlock();
 356                                 return -ENODEV;
 357                         }
 358                 }
 359                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 360                                                     scoped);
 361                 rcu_read_unlock();
 362
 363                 if (!(ipv6_can_nonlocal_bind(net, isk) || has_addr ||
 364                       addr_type == IPV6_ADDR_ANY))
 365                         return -EADDRNOTAVAIL;
 366
 367                 if (scoped)
 368                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 369 #endif
 370         } else {
 371                 return -EAFNOSUPPORT;
 372         }
 373         return 0;
 374 }
 375
 376 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 377 {
 378         if (saddr->sa_family == AF_INET) {
 379                 struct inet_sock *isk = inet_sk(sk);
 380                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 381                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 382 #if IS_ENABLED(CONFIG_IPV6)
 383         } else if (saddr->sa_family == AF_INET6) {
 384                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 385                 struct ipv6_pinfo *np = inet6_sk(sk);
 386                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 387 #endif
 388         }
 389 }
 390
 391 /*
 392  * We need our own bind because there are no privileged id's == local ports.
 393  * Moreover, we don't allow binding to multi- and broadcast addresses.
 394  */
 395
 396 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 397 {
 398         struct inet_sock *isk = inet_sk(sk);
 399         unsigned short snum;
 400         int err;
 401         int dif = sk->sk_bound_dev_if;
 402
 403         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 404         if (err)
 405                 return err;
 406
 407         lock_sock(sk);
 408
 409         err = -EINVAL;
 410         if (isk->inet_num != 0)
 411                 goto out;
 412
 413         err = -EADDRINUSE;
 414         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 415         if (ping_get_port(sk, snum) != 0) {
 416                 /* Restore possibly modified sk->sk_bound_dev_if by ping_check_bind_addr(). */
 417                 sk->sk_bound_dev_if = dif;
 418                 goto out;
 419         }
 420         ping_set_saddr(sk, uaddr);
 421
 422         pr_debug("after bind(): num = %hu, dif = %d\n",
 423                  isk->inet_num,
 424                  sk->sk_bound_dev_if);
 425
 426         err = 0;
 427         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 428                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 429 #if IS_ENABLED(CONFIG_IPV6)
 430         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 431                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 432 #endif
 433
 434         if (snum)
 435                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 436         isk->inet_sport = htons(isk->inet_num);
 437         isk->inet_daddr = 0;
 438         isk->inet_dport = 0;
 439
 440 #if IS_ENABLED(CONFIG_IPV6)
 441         if (sk->sk_family == AF_INET6)
 442                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 443 #endif
 444
 445         sk_dst_reset(sk);
 446 out:
 447         release_sock(sk);
 448         pr_debug("ping_v4_bind -> %d\n", err);
 449         return err;
 450 }
 451 EXPORT_SYMBOL_GPL(ping_bind);
 452
 453 /*
 454  * Is this a supported type of ICMP message?
 455  */
 456
 457 static inline int ping_supported(int family, int type, int code)
 458 {
 459         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 460                (family == AF_INET && type == ICMP_EXT_ECHO && code == 0) ||
 461                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0) ||
 462                (family == AF_INET6 && type == ICMPV6_EXT_ECHO_REQUEST && code == 0);
 463 }
 464
 465 /*
 466  * This routine is called by the ICMP module when it gets some
 467  * sort of error condition.
 468  */
 469
 470 void ping_err(struct sk_buff *skb, int offset, u32 info)
 471 {
 472         int family;
 473         struct icmphdr *icmph;
 474         struct inet_sock *inet_sock;
 475         int type;
 476         int code;
 477         struct net *net = dev_net(skb->dev);
 478         struct sock *sk;
 479         int harderr;
 480         int err;
 481
 482         if (skb->protocol == htons(ETH_P_IP)) {
 483                 family = AF_INET;
 484                 type = icmp_hdr(skb)->type;
 485                 code = icmp_hdr(skb)->code;
 486                 icmph = (struct icmphdr *)(skb->data + offset);
 487         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 488                 family = AF_INET6;
 489                 type = icmp6_hdr(skb)->icmp6_type;
 490                 code = icmp6_hdr(skb)->icmp6_code;
 491                 icmph = (struct icmphdr *) (skb->data + offset);
 492         } else {
 493                 BUG();
 494         }
 495
 496         /* We assume the packet has already been checked by icmp_unreach */
 497
 498         if (!ping_supported(family, icmph->type, icmph->code))
 499                 return;
 500
 501         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 502                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 503                  ntohs(icmph->un.echo.sequence));
 504
 505         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 506         if (!sk) {
 507                 pr_debug("no socket, dropping\n");
 508                 return; /* No socket for error */
 509         }
 510         pr_debug("err on socket %p\n", sk);
 511
 512         err = 0;
 513         harderr = 0;
 514         inet_sock = inet_sk(sk);
 515
 516         if (skb->protocol == htons(ETH_P_IP)) {
 517                 switch (type) {
 518                 default:
 519                 case ICMP_TIME_EXCEEDED:
 520                         err = EHOSTUNREACH;
 521                         break;
 522                 case ICMP_SOURCE_QUENCH:
 523                         /* This is not a real error but ping wants to see it.
 524                          * Report it with some fake errno.
 525                          */
 526                         err = EREMOTEIO;
 527                         break;
 528                 case ICMP_PARAMETERPROB:
 529                         err = EPROTO;
 530                         harderr = 1;
 531                         break;
 532                 case ICMP_DEST_UNREACH:
 533                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 534                                 ipv4_sk_update_pmtu(skb, sk, info);
 535                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 536                                         err = EMSGSIZE;
 537                                         harderr = 1;
 538                                         break;
 539                                 }
 540                                 goto out;
 541                         }
 542                         err = EHOSTUNREACH;
 543                         if (code <= NR_ICMP_UNREACH) {
 544                                 harderr = icmp_err_convert[code].fatal;
 545                                 err = icmp_err_convert[code].errno;
 546                         }
 547                         break;
 548                 case ICMP_REDIRECT:
 549                         /* See ICMP_SOURCE_QUENCH */
 550                         ipv4_sk_redirect(skb, sk);
 551                         err = EREMOTEIO;
 552                         break;
 553                 }
 554 #if IS_ENABLED(CONFIG_IPV6)
 555         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 556                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 557 #endif
 558         }
 559
 560         /*
 561          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 562          *      4.1.3.3.
 563          */
 564         if ((family == AF_INET && !inet_sock->recverr) ||
 565             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 566                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 567                         goto out;
 568         } else {
 569                 if (family == AF_INET) {
 570                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 571                                       info, (u8 *)icmph);
 572 #if IS_ENABLED(CONFIG_IPV6)
 573                 } else if (family == AF_INET6) {
 574                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 575                                                    info, (u8 *)icmph);
 576 #endif
 577                 }
 578         }
 579         sk->sk_err = err;
 580         sk_error_report(sk);
 581 out:
 582         sock_put(sk);
 583 }
 584 EXPORT_SYMBOL_GPL(ping_err);
 585
 586 /*
 587  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 588  *      starting from the payload.
 589  */
 590
 591 int ping_getfrag(void *from, char *to,
 592                  int offset, int fraglen, int odd, struct sk_buff *skb)
 593 {
 594         struct pingfakehdr *pfh = (struct pingfakehdr *)from;
 595
 596         if (offset == 0) {
 597                 fraglen -= sizeof(struct icmphdr);
 598                 if (fraglen < 0)
 599                         BUG();
 600                 if (!csum_and_copy_from_iter_full(to + sizeof(struct icmphdr),
 601                             fraglen, &pfh->wcheck,
 602                             &pfh->msg->msg_iter))
 603                         return -EFAULT;
 604         } else if (offset < sizeof(struct icmphdr)) {
 605                         BUG();
 606         } else {
 607                 if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
 608                                             &pfh->msg->msg_iter))
 609                         return -EFAULT;
 610         }
 611
 612 #if IS_ENABLED(CONFIG_IPV6)
 613         /* For IPv6, checksum each skb as we go along, as expected by
 614          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 615          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 616          */
 617         if (pfh->family == AF_INET6) {
 618                 skb->csum = pfh->wcheck;
 619                 skb->ip_summed = CHECKSUM_NONE;
 620                 pfh->wcheck = 0;
 621         }
 622 #endif
 623
 624         return 0;
 625 }
 626 EXPORT_SYMBOL_GPL(ping_getfrag);
 627
 628 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 629                                        struct flowi4 *fl4)
 630 {
 631         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 632
 633         if (!skb)
 634                 return 0;
 635         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 636                 sizeof(struct icmphdr), pfh->wcheck);
 637         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 638         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 639         skb->ip_summed = CHECKSUM_NONE;
 640         return ip_push_pending_frames(sk, fl4);
 641 }
 642
 643 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 644                         void *user_icmph, size_t icmph_len)
 645 {
 646         u8 type, code;
 647
 648         if (len > 0xFFFF)
 649                 return -EMSGSIZE;
 650
 651         /* Must have at least a full ICMP header. */
 652         if (len < icmph_len)
 653                 return -EINVAL;
 654
 655         /*
 656          *      Check the flags.
 657          */
 658
 659         /* Mirror BSD error message compatibility */
 660         if (msg->msg_flags & MSG_OOB)
 661                 return -EOPNOTSUPP;
 662
 663         /*
 664          *      Fetch the ICMP header provided by the userland.
 665          *      iovec is modified! The ICMP header is consumed.
 666          */
 667         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 668                 return -EFAULT;
 669
 670         if (family == AF_INET) {
 671                 type = ((struct icmphdr *) user_icmph)->type;
 672                 code = ((struct icmphdr *) user_icmph)->code;
 673 #if IS_ENABLED(CONFIG_IPV6)
 674         } else if (family == AF_INET6) {
 675                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 676                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 677 #endif
 678         } else {
 679                 BUG();
 680         }
 681
 682         if (!ping_supported(family, type, code))
 683                 return -EINVAL;
 684
 685         return 0;
 686 }
 687 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 688
 689 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 690 {
 691         struct net *net = sock_net(sk);
 692         struct flowi4 fl4;
 693         struct inet_sock *inet = inet_sk(sk);
 694         struct ipcm_cookie ipc;
 695         struct icmphdr user_icmph;
 696         struct pingfakehdr pfh;
 697         struct rtable *rt = NULL;
 698         struct ip_options_data opt_copy;
 699         int free = 0;
 700         __be32 saddr, daddr, faddr;
 701         u8  tos;
 702         int err;
 703
 704         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 705
 706         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 707                                   sizeof(user_icmph));
 708         if (err)
 709                 return err;
 710
 711         /*
 712          *      Get and verify the address.
 713          */
 714
 715         if (msg->msg_name) {
 716                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 717                 if (msg->msg_namelen < sizeof(*usin))
 718                         return -EINVAL;
 719                 if (usin->sin_family != AF_INET)
 720                         return -EAFNOSUPPORT;
 721                 daddr = usin->sin_addr.s_addr;
 722                 /* no remote port */
 723         } else {
 724                 if (sk->sk_state != TCP_ESTABLISHED)
 725                         return -EDESTADDRREQ;
 726                 daddr = inet->inet_daddr;
 727                 /* no remote port */
 728         }
 729
 730         ipcm_init_sk(&ipc, inet);
 731
 732         if (msg->msg_controllen) {
 733                 err = ip_cmsg_send(sk, msg, &ipc, false);
 734                 if (unlikely(err)) {
 735                         kfree(ipc.opt);
 736                         return err;
 737                 }
 738                 if (ipc.opt)
 739                         free = 1;
 740         }
 741         if (!ipc.opt) {
 742                 struct ip_options_rcu *inet_opt;
 743
 744                 rcu_read_lock();
 745                 inet_opt = rcu_dereference(inet->inet_opt);
 746                 if (inet_opt) {
 747                         memcpy(&opt_copy, inet_opt,
 748                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 749                         ipc.opt = &opt_copy.opt;
 750                 }
 751                 rcu_read_unlock();
 752         }
 753
 754         saddr = ipc.addr;
 755         ipc.addr = faddr = daddr;
 756
 757         if (ipc.opt && ipc.opt->opt.srr) {
 758                 if (!daddr) {
 759                         err = -EINVAL;
 760                         goto out_free;
 761                 }
 762                 faddr = ipc.opt->opt.faddr;
 763         }
 764         tos = get_rttos(&ipc, inet);
 765         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 766             (msg->msg_flags & MSG_DONTROUTE) ||
 767             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 768                 tos |= RTO_ONLINK;
 769         }
 770
 771         if (ipv4_is_multicast(daddr)) {
 772                 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
 773                         ipc.oif = inet->mc_index;
 774                 if (!saddr)
 775                         saddr = inet->mc_addr;
 776         } else if (!ipc.oif)
 777                 ipc.oif = inet->uc_index;
 778
 779         flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos,
 780                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 781                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
 782                            sk->sk_uid);
 783
 784         fl4.fl4_icmp_type = user_icmph.type;
 785         fl4.fl4_icmp_code = user_icmph.code;
 786
 787         security_sk_classify_flow(sk, flowi4_to_flowi_common(&fl4));
 788         rt = ip_route_output_flow(net, &fl4, sk);
 789         if (IS_ERR(rt)) {
 790                 err = PTR_ERR(rt);
 791                 rt = NULL;
 792                 if (err == -ENETUNREACH)
 793                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 794                 goto out;
 795         }
 796
 797         err = -EACCES;
 798         if ((rt->rt_flags & RTCF_BROADCAST) &&
 799             !sock_flag(sk, SOCK_BROADCAST))
 800                 goto out;
 801
 802         if (msg->msg_flags & MSG_CONFIRM)
 803                 goto do_confirm;
 804 back_from_confirm:
 805
 806         if (!ipc.addr)
 807                 ipc.addr = fl4.daddr;
 808
 809         lock_sock(sk);
 810
 811         pfh.icmph.type = user_icmph.type; /* already checked */
 812         pfh.icmph.code = user_icmph.code; /* ditto */
 813         pfh.icmph.checksum = 0;
 814         pfh.icmph.un.echo.id = inet->inet_sport;
 815         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 816         pfh.msg = msg;
 817         pfh.wcheck = 0;
 818         pfh.family = AF_INET;
 819
 820         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 821                         0, &ipc, &rt, msg->msg_flags);
 822         if (err)
 823                 ip_flush_pending_frames(sk);
 824         else
 825                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 826         release_sock(sk);
 827
 828 out:
 829         ip_rt_put(rt);
 830 out_free:
 831         if (free)
 832                 kfree(ipc.opt);
 833         if (!err) {
 834                 icmp_out_count(sock_net(sk), user_icmph.type);
 835                 return len;
 836         }
 837         return err;
 838
 839 do_confirm:
 840         if (msg->msg_flags & MSG_PROBE)
 841                 dst_confirm_neigh(&rt->dst, &fl4.daddr);
 842         if (!(msg->msg_flags & MSG_PROBE) || len)
 843                 goto back_from_confirm;
 844         err = 0;
 845         goto out;
 846 }
 847
 848 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 849                  int flags, int *addr_len)
 850 {
 851         struct inet_sock *isk = inet_sk(sk);
 852         int family = sk->sk_family;
 853         struct sk_buff *skb;
 854         int copied, err;
 855
 856         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 857
 858         err = -EOPNOTSUPP;
 859         if (flags & MSG_OOB)
 860                 goto out;
 861
 862         if (flags & MSG_ERRQUEUE)
 863                 return inet_recv_error(sk, msg, len, addr_len);
 864
 865         skb = skb_recv_datagram(sk, flags, noblock, &err);
 866         if (!skb)
 867                 goto out;
 868
 869         copied = skb->len;
 870         if (copied > len) {
 871                 msg->msg_flags |= MSG_TRUNC;
 872                 copied = len;
 873         }
 874
 875         /* Don't bother checking the checksum */
 876         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 877         if (err)
 878                 goto done;
 879
 880         sock_recv_timestamp(msg, sk, skb);
 881
 882         /* Copy the address and add cmsg data. */
 883         if (family == AF_INET) {
 884                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 885
 886                 if (sin) {
 887                         sin->sin_family = AF_INET;
 888                         sin->sin_port = 0 /* skb->h.uh->source */;
 889                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 890                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 891                         *addr_len = sizeof(*sin);
 892                 }
 893
 894                 if (isk->cmsg_flags)
 895                         ip_cmsg_recv(msg, skb);
 896
 897 #if IS_ENABLED(CONFIG_IPV6)
 898         } else if (family == AF_INET6) {
 899                 struct ipv6_pinfo *np = inet6_sk(sk);
 900                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 901                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 902
 903                 if (sin6) {
 904                         sin6->sin6_family = AF_INET6;
 905                         sin6->sin6_port = 0;
 906                         sin6->sin6_addr = ip6->saddr;
 907                         sin6->sin6_flowinfo = 0;
 908                         if (np->sndflow)
 909                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 910                         sin6->sin6_scope_id =
 911                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 912                                                     inet6_iif(skb));
 913                         *addr_len = sizeof(*sin6);
 914                 }
 915
 916                 if (inet6_sk(sk)->rxopt.all)
 917                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 918                 if (skb->protocol == htons(ETH_P_IPV6) &&
 919                     inet6_sk(sk)->rxopt.all)
 920                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 921                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 922                         ip_cmsg_recv(msg, skb);
 923 #endif
 924         } else {
 925                 BUG();
 926         }
 927
 928         err = copied;
 929
 930 done:
 931         skb_free_datagram(sk, skb);
 932 out:
 933         pr_debug("ping_recvmsg -> %d\n", err);
 934         return err;
 935 }
 936 EXPORT_SYMBOL_GPL(ping_recvmsg);
 937
 938 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 939 {
 940         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 941                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 942         if (sock_queue_rcv_skb(sk, skb) < 0) {
 943                 kfree_skb(skb);
 944                 pr_debug("ping_queue_rcv_skb -> failed\n");
 945                 return -1;
 946         }
 947         return 0;
 948 }
 949 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 950
 951
 952 /*
 953  *      All we need to do is get the socket.
 954  */
 955
 956 bool ping_rcv(struct sk_buff *skb)
 957 {
 958         struct sock *sk;
 959         struct net *net = dev_net(skb->dev);
 960         struct icmphdr *icmph = icmp_hdr(skb);
 961         bool rc = false;
 962
 963         /* We assume the packet has already been checked by icmp_rcv */
 964
 965         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 966                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 967
 968         /* Push ICMP header back */
 969         skb_push(skb, skb->data - (u8 *)icmph);
 970
 971         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 972         if (sk) {
 973                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 974
 975                 pr_debug("rcv on socket %p\n", sk);
 976                 if (skb2 && !ping_queue_rcv_skb(sk, skb2))
 977                         rc = true;
 978                 sock_put(sk);
 979         }
 980
 981         if (!rc)
 982                 pr_debug("no socket, dropping\n");
 983
 984         return rc;
 985 }
 986 EXPORT_SYMBOL_GPL(ping_rcv);
 987
 988 struct proto ping_prot = {
 989         .name =         "PING",
 990         .owner =        THIS_MODULE,
 991         .init =         ping_init_sock,
 992         .close =        ping_close,
 993         .connect =      ip4_datagram_connect,
 994         .disconnect =   __udp_disconnect,
 995         .setsockopt =   ip_setsockopt,
 996         .getsockopt =   ip_getsockopt,
 997         .sendmsg =      ping_v4_sendmsg,
 998         .recvmsg =      ping_recvmsg,
 999         .bind =         ping_bind,
1000         .backlog_rcv =  ping_queue_rcv_skb,
1001         .release_cb =   ip4_datagram_release_cb,
1002         .hash =         ping_hash,
1003         .unhash =       ping_unhash,
1004         .get_port =     ping_get_port,
1005         .put_port =     ping_unhash,
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         __acquires(ping_table.lock)
1065 {
1066         struct ping_iter_state *state = seq->private;
1067         state->bucket = 0;
1068         state->family = family;
1069
1070         read_lock_bh(&ping_table.lock);
1071
1072         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1073 }
1074 EXPORT_SYMBOL_GPL(ping_seq_start);
1075
1076 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1077 {
1078         return ping_seq_start(seq, pos, AF_INET);
1079 }
1080
1081 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1082 {
1083         struct sock *sk;
1084
1085         if (v == SEQ_START_TOKEN)
1086                 sk = ping_get_idx(seq, 0);
1087         else
1088                 sk = ping_get_next(seq, v);
1089
1090         ++*pos;
1091         return sk;
1092 }
1093 EXPORT_SYMBOL_GPL(ping_seq_next);
1094
1095 void ping_seq_stop(struct seq_file *seq, void *v)
1096         __releases(ping_table.lock)
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 %u",
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                 refcount_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         .start          = ping_v4_seq_start,
1141         .show           = ping_v4_seq_show,
1142         .next           = ping_seq_next,
1143         .stop           = ping_seq_stop,
1144 };
1145
1146 static int __net_init ping_v4_proc_init_net(struct net *net)
1147 {
1148         if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
1149                         sizeof(struct ping_iter_state)))
1150                 return -ENOMEM;
1151         return 0;
1152 }
1153
1154 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1155 {
1156         remove_proc_entry("icmp", net->proc_net);
1157 }
1158
1159 static struct pernet_operations ping_v4_net_ops = {
1160         .init = ping_v4_proc_init_net,
1161         .exit = ping_v4_proc_exit_net,
1162 };
1163
1164 int __init ping_proc_init(void)
1165 {
1166         return register_pernet_subsys(&ping_v4_net_ops);
1167 }
1168
1169 void ping_proc_exit(void)
1170 {
1171         unregister_pernet_subsys(&ping_v4_net_ops);
1172 }
1173
1174 #endif
1175
1176 void __init ping_init(void)
1177 {
1178         int i;
1179
1180         for (i = 0; i < PING_HTABLE_SIZE; i++)
1181                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1182         rwlock_init(&ping_table.lock);
1183 }