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                 return NULL;
 191         }
 192
 193         read_lock_bh(&ping_table.lock);
 194
 195         ping_portaddr_for_each_entry(sk, hnode, hslot) {
 196                 isk = inet_sk(sk);
 197
 198                 pr_debug("iterate\n");
 199                 if (isk->inet_num != ident)
 200                         continue;
 201
 202                 if (skb->protocol == htons(ETH_P_IP) &&
 203                     sk->sk_family == AF_INET) {
 204                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 205                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
 206                                  sk->sk_bound_dev_if);
 207
 208                         if (isk->inet_rcv_saddr &&
 209                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 210                                 continue;
 211 #if IS_ENABLED(CONFIG_IPV6)
 212                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
 213                            sk->sk_family == AF_INET6) {
 214
 215                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 216                                  (int) isk->inet_num,
 217                                  &sk->sk_v6_rcv_saddr,
 218                                  sk->sk_bound_dev_if);
 219
 220                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 221                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 222                                              &ipv6_hdr(skb)->daddr))
 223                                 continue;
 224 #endif
 225                 } else {
 226                         continue;
 227                 }
 228
 229                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif &&
 230                     sk->sk_bound_dev_if != sdif)
 231                         continue;
 232
 233                 sock_hold(sk);
 234                 goto exit;
 235         }
 236
 237         sk = NULL;
 238 exit:
 239         read_unlock_bh(&ping_table.lock);
 240
 241         return sk;
 242 }
 243
 244 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 245                                           kgid_t *high)
 246 {
 247         kgid_t *data = net->ipv4.ping_group_range.range;
 248         unsigned int seq;
 249
 250         do {
 251                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 252
 253                 *low = data[0];
 254                 *high = data[1];
 255         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 256 }
 257
 258
 259 int ping_init_sock(struct sock *sk)
 260 {
 261         struct net *net = sock_net(sk);
 262         kgid_t group = current_egid();
 263         struct group_info *group_info;
 264         int i;
 265         kgid_t low, high;
 266         int ret = 0;
 267
 268         if (sk->sk_family == AF_INET6)
 269                 sk->sk_ipv6only = 1;
 270
 271         inet_get_ping_group_range_net(net, &low, &high);
 272         if (gid_lte(low, group) && gid_lte(group, high))
 273                 return 0;
 274
 275         group_info = get_current_groups();
 276         for (i = 0; i < group_info->ngroups; i++) {
 277                 kgid_t gid = group_info->gid[i];
 278
 279                 if (gid_lte(low, gid) && gid_lte(gid, high))
 280                         goto out_release_group;
 281         }
 282
 283         ret = -EACCES;
 284
 285 out_release_group:
 286         put_group_info(group_info);
 287         return ret;
 288 }
 289 EXPORT_SYMBOL_GPL(ping_init_sock);
 290
 291 void ping_close(struct sock *sk, long timeout)
 292 {
 293         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 294                  inet_sk(sk), inet_sk(sk)->inet_num);
 295         pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
 296
 297         sk_common_release(sk);
 298 }
 299 EXPORT_SYMBOL_GPL(ping_close);
 300
 301 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 302 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 303                                 struct sockaddr *uaddr, int addr_len)
 304 {
 305         struct net *net = sock_net(sk);
 306         if (sk->sk_family == AF_INET) {
 307                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 308                 int chk_addr_ret;
 309
 310                 if (addr_len < sizeof(*addr))
 311                         return -EINVAL;
 312
 313                 if (addr->sin_family != AF_INET &&
 314                     !(addr->sin_family == AF_UNSPEC &&
 315                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 316                         return -EAFNOSUPPORT;
 317
 318                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 319                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 320
 321                 chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
 322
 323                 if (!inet_addr_valid_or_nonlocal(net, inet_sk(sk),
 324                                                  addr->sin_addr.s_addr,
 325                                                  chk_addr_ret))
 326                         return -EADDRNOTAVAIL;
 327
 328 #if IS_ENABLED(CONFIG_IPV6)
 329         } else if (sk->sk_family == AF_INET6) {
 330                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 331                 int addr_type, scoped, has_addr;
 332                 struct net_device *dev = NULL;
 333
 334                 if (addr_len < sizeof(*addr))
 335                         return -EINVAL;
 336
 337                 if (addr->sin6_family != AF_INET6)
 338                         return -EAFNOSUPPORT;
 339
 340                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 341                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 342
 343                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 344                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 345                 if ((addr_type != IPV6_ADDR_ANY &&
 346                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 347                     (scoped && !addr->sin6_scope_id))
 348                         return -EINVAL;
 349
 350                 rcu_read_lock();
 351                 if (addr->sin6_scope_id) {
 352                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 353                         if (!dev) {
 354                                 rcu_read_unlock();
 355                                 return -ENODEV;
 356                         }
 357                 }
 358                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 359                                                     scoped);
 360                 rcu_read_unlock();
 361
 362                 if (!(ipv6_can_nonlocal_bind(net, isk) || has_addr ||
 363                       addr_type == IPV6_ADDR_ANY))
 364                         return -EADDRNOTAVAIL;
 365
 366                 if (scoped)
 367                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 368 #endif
 369         } else {
 370                 return -EAFNOSUPPORT;
 371         }
 372         return 0;
 373 }
 374
 375 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 376 {
 377         if (saddr->sa_family == AF_INET) {
 378                 struct inet_sock *isk = inet_sk(sk);
 379                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 380                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 381 #if IS_ENABLED(CONFIG_IPV6)
 382         } else if (saddr->sa_family == AF_INET6) {
 383                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 384                 struct ipv6_pinfo *np = inet6_sk(sk);
 385                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 386 #endif
 387         }
 388 }
 389
 390 /*
 391  * We need our own bind because there are no privileged id's == local ports.
 392  * Moreover, we don't allow binding to multi- and broadcast addresses.
 393  */
 394
 395 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 396 {
 397         struct inet_sock *isk = inet_sk(sk);
 398         unsigned short snum;
 399         int err;
 400         int dif = sk->sk_bound_dev_if;
 401
 402         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 403         if (err)
 404                 return err;
 405
 406         lock_sock(sk);
 407
 408         err = -EINVAL;
 409         if (isk->inet_num != 0)
 410                 goto out;
 411
 412         err = -EADDRINUSE;
 413         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 414         if (ping_get_port(sk, snum) != 0) {
 415                 /* Restore possibly modified sk->sk_bound_dev_if by ping_check_bind_addr(). */
 416                 sk->sk_bound_dev_if = dif;
 417                 goto out;
 418         }
 419         ping_set_saddr(sk, uaddr);
 420
 421         pr_debug("after bind(): num = %hu, dif = %d\n",
 422                  isk->inet_num,
 423                  sk->sk_bound_dev_if);
 424
 425         err = 0;
 426         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 427                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 428 #if IS_ENABLED(CONFIG_IPV6)
 429         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 430                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 431 #endif
 432
 433         if (snum)
 434                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 435         isk->inet_sport = htons(isk->inet_num);
 436         isk->inet_daddr = 0;
 437         isk->inet_dport = 0;
 438
 439 #if IS_ENABLED(CONFIG_IPV6)
 440         if (sk->sk_family == AF_INET6)
 441                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 442 #endif
 443
 444         sk_dst_reset(sk);
 445 out:
 446         release_sock(sk);
 447         pr_debug("ping_v4_bind -> %d\n", err);
 448         return err;
 449 }
 450 EXPORT_SYMBOL_GPL(ping_bind);
 451
 452 /*
 453  * Is this a supported type of ICMP message?
 454  */
 455
 456 static inline int ping_supported(int family, int type, int code)
 457 {
 458         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 459                (family == AF_INET && type == ICMP_EXT_ECHO && code == 0) ||
 460                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0) ||
 461                (family == AF_INET6 && type == ICMPV6_EXT_ECHO_REQUEST && code == 0);
 462 }
 463
 464 /*
 465  * This routine is called by the ICMP module when it gets some
 466  * sort of error condition.
 467  */
 468
 469 void ping_err(struct sk_buff *skb, int offset, u32 info)
 470 {
 471         int family;
 472         struct icmphdr *icmph;
 473         struct inet_sock *inet_sock;
 474         int type;
 475         int code;
 476         struct net *net = dev_net(skb->dev);
 477         struct sock *sk;
 478         int harderr;
 479         int err;
 480
 481         if (skb->protocol == htons(ETH_P_IP)) {
 482                 family = AF_INET;
 483                 type = icmp_hdr(skb)->type;
 484                 code = icmp_hdr(skb)->code;
 485                 icmph = (struct icmphdr *)(skb->data + offset);
 486         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 487                 family = AF_INET6;
 488                 type = icmp6_hdr(skb)->icmp6_type;
 489                 code = icmp6_hdr(skb)->icmp6_code;
 490                 icmph = (struct icmphdr *) (skb->data + offset);
 491         } else {
 492                 BUG();
 493         }
 494
 495         /* We assume the packet has already been checked by icmp_unreach */
 496
 497         if (!ping_supported(family, icmph->type, icmph->code))
 498                 return;
 499
 500         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 501                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 502                  ntohs(icmph->un.echo.sequence));
 503
 504         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 505         if (!sk) {
 506                 pr_debug("no socket, dropping\n");
 507                 return; /* No socket for error */
 508         }
 509         pr_debug("err on socket %p\n", sk);
 510
 511         err = 0;
 512         harderr = 0;
 513         inet_sock = inet_sk(sk);
 514
 515         if (skb->protocol == htons(ETH_P_IP)) {
 516                 switch (type) {
 517                 default:
 518                 case ICMP_TIME_EXCEEDED:
 519                         err = EHOSTUNREACH;
 520                         break;
 521                 case ICMP_SOURCE_QUENCH:
 522                         /* This is not a real error but ping wants to see it.
 523                          * Report it with some fake errno.
 524                          */
 525                         err = EREMOTEIO;
 526                         break;
 527                 case ICMP_PARAMETERPROB:
 528                         err = EPROTO;
 529                         harderr = 1;
 530                         break;
 531                 case ICMP_DEST_UNREACH:
 532                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 533                                 ipv4_sk_update_pmtu(skb, sk, info);
 534                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 535                                         err = EMSGSIZE;
 536                                         harderr = 1;
 537                                         break;
 538                                 }
 539                                 goto out;
 540                         }
 541                         err = EHOSTUNREACH;
 542                         if (code <= NR_ICMP_UNREACH) {
 543                                 harderr = icmp_err_convert[code].fatal;
 544                                 err = icmp_err_convert[code].errno;
 545                         }
 546                         break;
 547                 case ICMP_REDIRECT:
 548                         /* See ICMP_SOURCE_QUENCH */
 549                         ipv4_sk_redirect(skb, sk);
 550                         err = EREMOTEIO;
 551                         break;
 552                 }
 553 #if IS_ENABLED(CONFIG_IPV6)
 554         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 555                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 556 #endif
 557         }
 558
 559         /*
 560          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 561          *      4.1.3.3.
 562          */
 563         if ((family == AF_INET && !inet_sock->recverr) ||
 564             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 565                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 566                         goto out;
 567         } else {
 568                 if (family == AF_INET) {
 569                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 570                                       info, (u8 *)icmph);
 571 #if IS_ENABLED(CONFIG_IPV6)
 572                 } else if (family == AF_INET6) {
 573                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 574                                                    info, (u8 *)icmph);
 575 #endif
 576                 }
 577         }
 578         sk->sk_err = err;
 579         sk_error_report(sk);
 580 out:
 581         sock_put(sk);
 582 }
 583 EXPORT_SYMBOL_GPL(ping_err);
 584
 585 /*
 586  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 587  *      starting from the payload.
 588  */
 589
 590 int ping_getfrag(void *from, char *to,
 591                  int offset, int fraglen, int odd, struct sk_buff *skb)
 592 {
 593         struct pingfakehdr *pfh = (struct pingfakehdr *)from;
 594
 595         if (offset == 0) {
 596                 fraglen -= sizeof(struct icmphdr);
 597                 if (fraglen < 0)
 598                         BUG();
 599                 if (!csum_and_copy_from_iter_full(to + sizeof(struct icmphdr),
 600                             fraglen, &pfh->wcheck,
 601                             &pfh->msg->msg_iter))
 602                         return -EFAULT;
 603         } else if (offset < sizeof(struct icmphdr)) {
 604                         BUG();
 605         } else {
 606                 if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
 607                                             &pfh->msg->msg_iter))
 608                         return -EFAULT;
 609         }
 610
 611 #if IS_ENABLED(CONFIG_IPV6)
 612         /* For IPv6, checksum each skb as we go along, as expected by
 613          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 614          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 615          */
 616         if (pfh->family == AF_INET6) {
 617                 skb->csum = pfh->wcheck;
 618                 skb->ip_summed = CHECKSUM_NONE;
 619                 pfh->wcheck = 0;
 620         }
 621 #endif
 622
 623         return 0;
 624 }
 625 EXPORT_SYMBOL_GPL(ping_getfrag);
 626
 627 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 628                                        struct flowi4 *fl4)
 629 {
 630         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 631
 632         if (!skb)
 633                 return 0;
 634         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 635                 sizeof(struct icmphdr), pfh->wcheck);
 636         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 637         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 638         skb->ip_summed = CHECKSUM_NONE;
 639         return ip_push_pending_frames(sk, fl4);
 640 }
 641
 642 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 643                         void *user_icmph, size_t icmph_len)
 644 {
 645         u8 type, code;
 646
 647         if (len > 0xFFFF)
 648                 return -EMSGSIZE;
 649
 650         /* Must have at least a full ICMP header. */
 651         if (len < icmph_len)
 652                 return -EINVAL;
 653
 654         /*
 655          *      Check the flags.
 656          */
 657
 658         /* Mirror BSD error message compatibility */
 659         if (msg->msg_flags & MSG_OOB)
 660                 return -EOPNOTSUPP;
 661
 662         /*
 663          *      Fetch the ICMP header provided by the userland.
 664          *      iovec is modified! The ICMP header is consumed.
 665          */
 666         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 667                 return -EFAULT;
 668
 669         if (family == AF_INET) {
 670                 type = ((struct icmphdr *) user_icmph)->type;
 671                 code = ((struct icmphdr *) user_icmph)->code;
 672 #if IS_ENABLED(CONFIG_IPV6)
 673         } else if (family == AF_INET6) {
 674                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 675                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 676 #endif
 677         } else {
 678                 BUG();
 679         }
 680
 681         if (!ping_supported(family, type, code))
 682                 return -EINVAL;
 683
 684         return 0;
 685 }
 686 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 687
 688 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 689 {
 690         struct net *net = sock_net(sk);
 691         struct flowi4 fl4;
 692         struct inet_sock *inet = inet_sk(sk);
 693         struct ipcm_cookie ipc;
 694         struct icmphdr user_icmph;
 695         struct pingfakehdr pfh;
 696         struct rtable *rt = NULL;
 697         struct ip_options_data opt_copy;
 698         int free = 0;
 699         __be32 saddr, daddr, faddr;
 700         u8  tos;
 701         int err;
 702
 703         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 704
 705         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 706                                   sizeof(user_icmph));
 707         if (err)
 708                 return err;
 709
 710         /*
 711          *      Get and verify the address.
 712          */
 713
 714         if (msg->msg_name) {
 715                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 716                 if (msg->msg_namelen < sizeof(*usin))
 717                         return -EINVAL;
 718                 if (usin->sin_family != AF_INET)
 719                         return -EAFNOSUPPORT;
 720                 daddr = usin->sin_addr.s_addr;
 721                 /* no remote port */
 722         } else {
 723                 if (sk->sk_state != TCP_ESTABLISHED)
 724                         return -EDESTADDRREQ;
 725                 daddr = inet->inet_daddr;
 726                 /* no remote port */
 727         }
 728
 729         ipcm_init_sk(&ipc, inet);
 730
 731         if (msg->msg_controllen) {
 732                 err = ip_cmsg_send(sk, msg, &ipc, false);
 733                 if (unlikely(err)) {
 734                         kfree(ipc.opt);
 735                         return err;
 736                 }
 737                 if (ipc.opt)
 738                         free = 1;
 739         }
 740         if (!ipc.opt) {
 741                 struct ip_options_rcu *inet_opt;
 742
 743                 rcu_read_lock();
 744                 inet_opt = rcu_dereference(inet->inet_opt);
 745                 if (inet_opt) {
 746                         memcpy(&opt_copy, inet_opt,
 747                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 748                         ipc.opt = &opt_copy.opt;
 749                 }
 750                 rcu_read_unlock();
 751         }
 752
 753         saddr = ipc.addr;
 754         ipc.addr = faddr = daddr;
 755
 756         if (ipc.opt && ipc.opt->opt.srr) {
 757                 if (!daddr) {
 758                         err = -EINVAL;
 759                         goto out_free;
 760                 }
 761                 faddr = ipc.opt->opt.faddr;
 762         }
 763         tos = get_rttos(&ipc, inet);
 764         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 765             (msg->msg_flags & MSG_DONTROUTE) ||
 766             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 767                 tos |= RTO_ONLINK;
 768         }
 769
 770         if (ipv4_is_multicast(daddr)) {
 771                 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
 772                         ipc.oif = inet->mc_index;
 773                 if (!saddr)
 774                         saddr = inet->mc_addr;
 775         } else if (!ipc.oif)
 776                 ipc.oif = inet->uc_index;
 777
 778         flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos,
 779                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 780                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
 781                            sk->sk_uid);
 782
 783         fl4.fl4_icmp_type = user_icmph.type;
 784         fl4.fl4_icmp_code = user_icmph.code;
 785
 786         security_sk_classify_flow(sk, flowi4_to_flowi_common(&fl4));
 787         rt = ip_route_output_flow(net, &fl4, sk);
 788         if (IS_ERR(rt)) {
 789                 err = PTR_ERR(rt);
 790                 rt = NULL;
 791                 if (err == -ENETUNREACH)
 792                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 793                 goto out;
 794         }
 795
 796         err = -EACCES;
 797         if ((rt->rt_flags & RTCF_BROADCAST) &&
 798             !sock_flag(sk, SOCK_BROADCAST))
 799                 goto out;
 800
 801         if (msg->msg_flags & MSG_CONFIRM)
 802                 goto do_confirm;
 803 back_from_confirm:
 804
 805         if (!ipc.addr)
 806                 ipc.addr = fl4.daddr;
 807
 808         lock_sock(sk);
 809
 810         pfh.icmph.type = user_icmph.type; /* already checked */
 811         pfh.icmph.code = user_icmph.code; /* ditto */
 812         pfh.icmph.checksum = 0;
 813         pfh.icmph.un.echo.id = inet->inet_sport;
 814         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 815         pfh.msg = msg;
 816         pfh.wcheck = 0;
 817         pfh.family = AF_INET;
 818
 819         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 820                         0, &ipc, &rt, msg->msg_flags);
 821         if (err)
 822                 ip_flush_pending_frames(sk);
 823         else
 824                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 825         release_sock(sk);
 826
 827 out:
 828         ip_rt_put(rt);
 829 out_free:
 830         if (free)
 831                 kfree(ipc.opt);
 832         if (!err) {
 833                 icmp_out_count(sock_net(sk), user_icmph.type);
 834                 return len;
 835         }
 836         return err;
 837
 838 do_confirm:
 839         if (msg->msg_flags & MSG_PROBE)
 840                 dst_confirm_neigh(&rt->dst, &fl4.daddr);
 841         if (!(msg->msg_flags & MSG_PROBE) || len)
 842                 goto back_from_confirm;
 843         err = 0;
 844         goto out;
 845 }
 846
 847 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 848                  int flags, int *addr_len)
 849 {
 850         struct inet_sock *isk = inet_sk(sk);
 851         int family = sk->sk_family;
 852         struct sk_buff *skb;
 853         int copied, err;
 854
 855         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 856
 857         err = -EOPNOTSUPP;
 858         if (flags & MSG_OOB)
 859                 goto out;
 860
 861         if (flags & MSG_ERRQUEUE)
 862                 return inet_recv_error(sk, msg, len, addr_len);
 863
 864         skb = skb_recv_datagram(sk, flags, noblock, &err);
 865         if (!skb)
 866                 goto out;
 867
 868         copied = skb->len;
 869         if (copied > len) {
 870                 msg->msg_flags |= MSG_TRUNC;
 871                 copied = len;
 872         }
 873
 874         /* Don't bother checking the checksum */
 875         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 876         if (err)
 877                 goto done;
 878
 879         sock_recv_timestamp(msg, sk, skb);
 880
 881         /* Copy the address and add cmsg data. */
 882         if (family == AF_INET) {
 883                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 884
 885                 if (sin) {
 886                         sin->sin_family = AF_INET;
 887                         sin->sin_port = 0 /* skb->h.uh->source */;
 888                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 889                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 890                         *addr_len = sizeof(*sin);
 891                 }
 892
 893                 if (isk->cmsg_flags)
 894                         ip_cmsg_recv(msg, skb);
 895
 896 #if IS_ENABLED(CONFIG_IPV6)
 897         } else if (family == AF_INET6) {
 898                 struct ipv6_pinfo *np = inet6_sk(sk);
 899                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 900                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 901
 902                 if (sin6) {
 903                         sin6->sin6_family = AF_INET6;
 904                         sin6->sin6_port = 0;
 905                         sin6->sin6_addr = ip6->saddr;
 906                         sin6->sin6_flowinfo = 0;
 907                         if (np->sndflow)
 908                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 909                         sin6->sin6_scope_id =
 910                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 911                                                     inet6_iif(skb));
 912                         *addr_len = sizeof(*sin6);
 913                 }
 914
 915                 if (inet6_sk(sk)->rxopt.all)
 916                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 917                 if (skb->protocol == htons(ETH_P_IPV6) &&
 918                     inet6_sk(sk)->rxopt.all)
 919                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 920                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 921                         ip_cmsg_recv(msg, skb);
 922 #endif
 923         } else {
 924                 BUG();
 925         }
 926
 927         err = copied;
 928
 929 done:
 930         skb_free_datagram(sk, skb);
 931 out:
 932         pr_debug("ping_recvmsg -> %d\n", err);
 933         return err;
 934 }
 935 EXPORT_SYMBOL_GPL(ping_recvmsg);
 936
 937 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 938 {
 939         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 940                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 941         if (sock_queue_rcv_skb(sk, skb) < 0) {
 942                 kfree_skb(skb);
 943                 pr_debug("ping_queue_rcv_skb -> failed\n");
 944                 return -1;
 945         }
 946         return 0;
 947 }
 948 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 949
 950
 951 /*
 952  *      All we need to do is get the socket.
 953  */
 954
 955 bool ping_rcv(struct sk_buff *skb)
 956 {
 957         struct sock *sk;
 958         struct net *net = dev_net(skb->dev);
 959         struct icmphdr *icmph = icmp_hdr(skb);
 960         bool rc = false;
 961
 962         /* We assume the packet has already been checked by icmp_rcv */
 963
 964         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 965                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 966
 967         /* Push ICMP header back */
 968         skb_push(skb, skb->data - (u8 *)icmph);
 969
 970         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 971         if (sk) {
 972                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 973
 974                 pr_debug("rcv on socket %p\n", sk);
 975                 if (skb2 && !ping_queue_rcv_skb(sk, skb2))
 976                         rc = true;
 977                 sock_put(sk);
 978         }
 979
 980         if (!rc)
 981                 pr_debug("no socket, dropping\n");
 982
 983         return rc;
 984 }
 985 EXPORT_SYMBOL_GPL(ping_rcv);
 986
 987 struct proto ping_prot = {
 988         .name =         "PING",
 989         .owner =        THIS_MODULE,
 990         .init =         ping_init_sock,
 991         .close =        ping_close,
 992         .connect =      ip4_datagram_connect,
 993         .disconnect =   __udp_disconnect,
 994         .setsockopt =   ip_setsockopt,
 995         .getsockopt =   ip_getsockopt,
 996         .sendmsg =      ping_v4_sendmsg,
 997         .recvmsg =      ping_recvmsg,
 998         .bind =         ping_bind,
 999         .backlog_rcv =  ping_queue_rcv_skb,
1000         .release_cb =   ip4_datagram_release_cb,
1001         .hash =         ping_hash,
1002         .unhash =       ping_unhash,
1003         .get_port =     ping_get_port,
1004         .put_port =     ping_unhash,
1005         .obj_size =     sizeof(struct inet_sock),
1006 };
1007 EXPORT_SYMBOL(ping_prot);
1008
1009 #ifdef CONFIG_PROC_FS
1010
1011 static struct sock *ping_get_first(struct seq_file *seq, int start)
1012 {
1013         struct sock *sk;
1014         struct ping_iter_state *state = seq->private;
1015         struct net *net = seq_file_net(seq);
1016
1017         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1018              ++state->bucket) {
1019                 struct hlist_nulls_node *node;
1020                 struct hlist_nulls_head *hslot;
1021
1022                 hslot = &ping_table.hash[state->bucket];
1023
1024                 if (hlist_nulls_empty(hslot))
1025                         continue;
1026
1027                 sk_nulls_for_each(sk, node, hslot) {
1028                         if (net_eq(sock_net(sk), net) &&
1029                             sk->sk_family == state->family)
1030                                 goto found;
1031                 }
1032         }
1033         sk = NULL;
1034 found:
1035         return sk;
1036 }
1037
1038 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1039 {
1040         struct ping_iter_state *state = seq->private;
1041         struct net *net = seq_file_net(seq);
1042
1043         do {
1044                 sk = sk_nulls_next(sk);
1045         } while (sk && (!net_eq(sock_net(sk), net)));
1046
1047         if (!sk)
1048                 return ping_get_first(seq, state->bucket + 1);
1049         return sk;
1050 }
1051
1052 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1053 {
1054         struct sock *sk = ping_get_first(seq, 0);
1055
1056         if (sk)
1057                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1058                         --pos;
1059         return pos ? NULL : sk;
1060 }
1061
1062 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1063         __acquires(ping_table.lock)
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         __releases(ping_table.lock)
1096 {
1097         read_unlock_bh(&ping_table.lock);
1098 }
1099 EXPORT_SYMBOL_GPL(ping_seq_stop);
1100
1101 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1102                 int bucket)
1103 {
1104         struct inet_sock *inet = inet_sk(sp);
1105         __be32 dest = inet->inet_daddr;
1106         __be32 src = inet->inet_rcv_saddr;
1107         __u16 destp = ntohs(inet->inet_dport);
1108         __u16 srcp = ntohs(inet->inet_sport);
1109
1110         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1111                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
1112                 bucket, src, srcp, dest, destp, sp->sk_state,
1113                 sk_wmem_alloc_get(sp),
1114                 sk_rmem_alloc_get(sp),
1115                 0, 0L, 0,
1116                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1117                 0, sock_i_ino(sp),
1118                 refcount_read(&sp->sk_refcnt), sp,
1119                 atomic_read(&sp->sk_drops));
1120 }
1121
1122 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1123 {
1124         seq_setwidth(seq, 127);
1125         if (v == SEQ_START_TOKEN)
1126                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1127                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1128                            "inode ref pointer drops");
1129         else {
1130                 struct ping_iter_state *state = seq->private;
1131
1132                 ping_v4_format_sock(v, seq, state->bucket);
1133         }
1134         seq_pad(seq, '\n');
1135         return 0;
1136 }
1137
1138 static const struct seq_operations ping_v4_seq_ops = {
1139         .start          = ping_v4_seq_start,
1140         .show           = ping_v4_seq_show,
1141         .next           = ping_seq_next,
1142         .stop           = ping_seq_stop,
1143 };
1144
1145 static int __net_init ping_v4_proc_init_net(struct net *net)
1146 {
1147         if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
1148                         sizeof(struct ping_iter_state)))
1149                 return -ENOMEM;
1150         return 0;
1151 }
1152
1153 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1154 {
1155         remove_proc_entry("icmp", net->proc_net);
1156 }
1157
1158 static struct pernet_operations ping_v4_net_ops = {
1159         .init = ping_v4_proc_init_net,
1160         .exit = ping_v4_proc_exit_net,
1161 };
1162
1163 int __init ping_proc_init(void)
1164 {
1165         return register_pernet_subsys(&ping_v4_net_ops);
1166 }
1167
1168 void ping_proc_exit(void)
1169 {
1170         unregister_pernet_subsys(&ping_v4_net_ops);
1171 }
1172
1173 #endif
1174
1175 void __init ping_init(void)
1176 {
1177         int i;
1178
1179         for (i = 0; i < PING_HTABLE_SIZE; i++)
1180                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1181         rwlock_init(&ping_table.lock);
1182 }