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 = skb->dev->ifindex;
 176
 177         if (skb->protocol == htons(ETH_P_IP)) {
 178                 pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
 179                          (int)ident, &ip_hdr(skb)->daddr, dif);
 180 #if IS_ENABLED(CONFIG_IPV6)
 181         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 182                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 183                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
 184 #endif
 185         }
 186
 187         read_lock_bh(&ping_table.lock);
 188
 189         ping_portaddr_for_each_entry(sk, hnode, hslot) {
 190                 isk = inet_sk(sk);
 191
 192                 pr_debug("iterate\n");
 193                 if (isk->inet_num != ident)
 194                         continue;
 195
 196                 if (skb->protocol == htons(ETH_P_IP) &&
 197                     sk->sk_family == AF_INET) {
 198                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 199                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
 200                                  sk->sk_bound_dev_if);
 201
 202                         if (isk->inet_rcv_saddr &&
 203                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 204                                 continue;
 205 #if IS_ENABLED(CONFIG_IPV6)
 206                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
 207                            sk->sk_family == AF_INET6) {
 208
 209                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 210                                  (int) isk->inet_num,
 211                                  &sk->sk_v6_rcv_saddr,
 212                                  sk->sk_bound_dev_if);
 213
 214                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 215                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 216                                              &ipv6_hdr(skb)->daddr))
 217                                 continue;
 218 #endif
 219                 } else {
 220                         continue;
 221                 }
 222
 223                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
 224                         continue;
 225
 226                 sock_hold(sk);
 227                 goto exit;
 228         }
 229
 230         sk = NULL;
 231 exit:
 232         read_unlock_bh(&ping_table.lock);
 233
 234         return sk;
 235 }
 236
 237 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 238                                           kgid_t *high)
 239 {
 240         kgid_t *data = net->ipv4.ping_group_range.range;
 241         unsigned int seq;
 242
 243         do {
 244                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 245
 246                 *low = data[0];
 247                 *high = data[1];
 248         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 249 }
 250
 251
 252 int ping_init_sock(struct sock *sk)
 253 {
 254         struct net *net = sock_net(sk);
 255         kgid_t group = current_egid();
 256         struct group_info *group_info;
 257         int i;
 258         kgid_t low, high;
 259         int ret = 0;
 260
 261         if (sk->sk_family == AF_INET6)
 262                 sk->sk_ipv6only = 1;
 263
 264         inet_get_ping_group_range_net(net, &low, &high);
 265         if (gid_lte(low, group) && gid_lte(group, high))
 266                 return 0;
 267
 268         group_info = get_current_groups();
 269         for (i = 0; i < group_info->ngroups; i++) {
 270                 kgid_t gid = group_info->gid[i];
 271
 272                 if (gid_lte(low, gid) && gid_lte(gid, high))
 273                         goto out_release_group;
 274         }
 275
 276         ret = -EACCES;
 277
 278 out_release_group:
 279         put_group_info(group_info);
 280         return ret;
 281 }
 282 EXPORT_SYMBOL_GPL(ping_init_sock);
 283
 284 void ping_close(struct sock *sk, long timeout)
 285 {
 286         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 287                  inet_sk(sk), inet_sk(sk)->inet_num);
 288         pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
 289
 290         sk_common_release(sk);
 291 }
 292 EXPORT_SYMBOL_GPL(ping_close);
 293
 294 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 295 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 296                                 struct sockaddr *uaddr, int addr_len) {
 297         struct net *net = sock_net(sk);
 298         if (sk->sk_family == AF_INET) {
 299                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 300                 int chk_addr_ret;
 301
 302                 if (addr_len < sizeof(*addr))
 303                         return -EINVAL;
 304
 305                 if (addr->sin_family != AF_INET &&
 306                     !(addr->sin_family == AF_UNSPEC &&
 307                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 308                         return -EAFNOSUPPORT;
 309
 310                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 311                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 312
 313                 chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
 314
 315                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 316                         chk_addr_ret = RTN_LOCAL;
 317
 318                 if ((!inet_can_nonlocal_bind(net, isk) &&
 319                      chk_addr_ret != RTN_LOCAL) ||
 320                     chk_addr_ret == RTN_MULTICAST ||
 321                     chk_addr_ret == RTN_BROADCAST)
 322                         return -EADDRNOTAVAIL;
 323
 324 #if IS_ENABLED(CONFIG_IPV6)
 325         } else if (sk->sk_family == AF_INET6) {
 326                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 327                 int addr_type, scoped, has_addr;
 328                 struct net_device *dev = NULL;
 329
 330                 if (addr_len < sizeof(*addr))
 331                         return -EINVAL;
 332
 333                 if (addr->sin6_family != AF_INET6)
 334                         return -EAFNOSUPPORT;
 335
 336                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 337                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 338
 339                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 340                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 341                 if ((addr_type != IPV6_ADDR_ANY &&
 342                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 343                     (scoped && !addr->sin6_scope_id))
 344                         return -EINVAL;
 345
 346                 rcu_read_lock();
 347                 if (addr->sin6_scope_id) {
 348                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 349                         if (!dev) {
 350                                 rcu_read_unlock();
 351                                 return -ENODEV;
 352                         }
 353                 }
 354                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 355                                                     scoped);
 356                 rcu_read_unlock();
 357
 358                 if (!(ipv6_can_nonlocal_bind(net, isk) || has_addr ||
 359                       addr_type == IPV6_ADDR_ANY))
 360                         return -EADDRNOTAVAIL;
 361
 362                 if (scoped)
 363                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 364 #endif
 365         } else {
 366                 return -EAFNOSUPPORT;
 367         }
 368         return 0;
 369 }
 370
 371 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 372 {
 373         if (saddr->sa_family == AF_INET) {
 374                 struct inet_sock *isk = inet_sk(sk);
 375                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 376                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 377 #if IS_ENABLED(CONFIG_IPV6)
 378         } else if (saddr->sa_family == AF_INET6) {
 379                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 380                 struct ipv6_pinfo *np = inet6_sk(sk);
 381                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 382 #endif
 383         }
 384 }
 385
 386 static void ping_clear_saddr(struct sock *sk, int dif)
 387 {
 388         sk->sk_bound_dev_if = dif;
 389         if (sk->sk_family == AF_INET) {
 390                 struct inet_sock *isk = inet_sk(sk);
 391                 isk->inet_rcv_saddr = isk->inet_saddr = 0;
 392 #if IS_ENABLED(CONFIG_IPV6)
 393         } else if (sk->sk_family == AF_INET6) {
 394                 struct ipv6_pinfo *np = inet6_sk(sk);
 395                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 396                 memset(&np->saddr, 0, sizeof(np->saddr));
 397 #endif
 398         }
 399 }
 400 /*
 401  * We need our own bind because there are no privileged id's == local ports.
 402  * Moreover, we don't allow binding to multi- and broadcast addresses.
 403  */
 404
 405 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 406 {
 407         struct inet_sock *isk = inet_sk(sk);
 408         unsigned short snum;
 409         int err;
 410         int dif = sk->sk_bound_dev_if;
 411
 412         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 413         if (err)
 414                 return err;
 415
 416         lock_sock(sk);
 417
 418         err = -EINVAL;
 419         if (isk->inet_num != 0)
 420                 goto out;
 421
 422         err = -EADDRINUSE;
 423         ping_set_saddr(sk, uaddr);
 424         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 425         if (ping_get_port(sk, snum) != 0) {
 426                 ping_clear_saddr(sk, dif);
 427                 goto out;
 428         }
 429
 430         pr_debug("after bind(): num = %hu, dif = %d\n",
 431                  isk->inet_num,
 432                  sk->sk_bound_dev_if);
 433
 434         err = 0;
 435         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 436                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 437 #if IS_ENABLED(CONFIG_IPV6)
 438         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 439                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 440 #endif
 441
 442         if (snum)
 443                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 444         isk->inet_sport = htons(isk->inet_num);
 445         isk->inet_daddr = 0;
 446         isk->inet_dport = 0;
 447
 448 #if IS_ENABLED(CONFIG_IPV6)
 449         if (sk->sk_family == AF_INET6)
 450                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 451 #endif
 452
 453         sk_dst_reset(sk);
 454 out:
 455         release_sock(sk);
 456         pr_debug("ping_v4_bind -> %d\n", err);
 457         return err;
 458 }
 459 EXPORT_SYMBOL_GPL(ping_bind);
 460
 461 /*
 462  * Is this a supported type of ICMP message?
 463  */
 464
 465 static inline int ping_supported(int family, int type, int code)
 466 {
 467         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 468                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0);
 469 }
 470
 471 /*
 472  * This routine is called by the ICMP module when it gets some
 473  * sort of error condition.
 474  */
 475
 476 void ping_err(struct sk_buff *skb, int offset, u32 info)
 477 {
 478         int family;
 479         struct icmphdr *icmph;
 480         struct inet_sock *inet_sock;
 481         int type;
 482         int code;
 483         struct net *net = dev_net(skb->dev);
 484         struct sock *sk;
 485         int harderr;
 486         int err;
 487
 488         if (skb->protocol == htons(ETH_P_IP)) {
 489                 family = AF_INET;
 490                 type = icmp_hdr(skb)->type;
 491                 code = icmp_hdr(skb)->code;
 492                 icmph = (struct icmphdr *)(skb->data + offset);
 493         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 494                 family = AF_INET6;
 495                 type = icmp6_hdr(skb)->icmp6_type;
 496                 code = icmp6_hdr(skb)->icmp6_code;
 497                 icmph = (struct icmphdr *) (skb->data + offset);
 498         } else {
 499                 BUG();
 500         }
 501
 502         /* We assume the packet has already been checked by icmp_unreach */
 503
 504         if (!ping_supported(family, icmph->type, icmph->code))
 505                 return;
 506
 507         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 508                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 509                  ntohs(icmph->un.echo.sequence));
 510
 511         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 512         if (!sk) {
 513                 pr_debug("no socket, dropping\n");
 514                 return; /* No socket for error */
 515         }
 516         pr_debug("err on socket %p\n", sk);
 517
 518         err = 0;
 519         harderr = 0;
 520         inet_sock = inet_sk(sk);
 521
 522         if (skb->protocol == htons(ETH_P_IP)) {
 523                 switch (type) {
 524                 default:
 525                 case ICMP_TIME_EXCEEDED:
 526                         err = EHOSTUNREACH;
 527                         break;
 528                 case ICMP_SOURCE_QUENCH:
 529                         /* This is not a real error but ping wants to see it.
 530                          * Report it with some fake errno.
 531                          */
 532                         err = EREMOTEIO;
 533                         break;
 534                 case ICMP_PARAMETERPROB:
 535                         err = EPROTO;
 536                         harderr = 1;
 537                         break;
 538                 case ICMP_DEST_UNREACH:
 539                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 540                                 ipv4_sk_update_pmtu(skb, sk, info);
 541                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 542                                         err = EMSGSIZE;
 543                                         harderr = 1;
 544                                         break;
 545                                 }
 546                                 goto out;
 547                         }
 548                         err = EHOSTUNREACH;
 549                         if (code <= NR_ICMP_UNREACH) {
 550                                 harderr = icmp_err_convert[code].fatal;
 551                                 err = icmp_err_convert[code].errno;
 552                         }
 553                         break;
 554                 case ICMP_REDIRECT:
 555                         /* See ICMP_SOURCE_QUENCH */
 556                         ipv4_sk_redirect(skb, sk);
 557                         err = EREMOTEIO;
 558                         break;
 559                 }
 560 #if IS_ENABLED(CONFIG_IPV6)
 561         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 562                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 563 #endif
 564         }
 565
 566         /*
 567          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 568          *      4.1.3.3.
 569          */
 570         if ((family == AF_INET && !inet_sock->recverr) ||
 571             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 572                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 573                         goto out;
 574         } else {
 575                 if (family == AF_INET) {
 576                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 577                                       info, (u8 *)icmph);
 578 #if IS_ENABLED(CONFIG_IPV6)
 579                 } else if (family == AF_INET6) {
 580                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 581                                                    info, (u8 *)icmph);
 582 #endif
 583                 }
 584         }
 585         sk->sk_err = err;
 586         sk->sk_error_report(sk);
 587 out:
 588         sock_put(sk);
 589 }
 590 EXPORT_SYMBOL_GPL(ping_err);
 591
 592 /*
 593  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 594  *      starting from the payload.
 595  */
 596
 597 int ping_getfrag(void *from, char *to,
 598                  int offset, int fraglen, int odd, struct sk_buff *skb)
 599 {
 600         struct pingfakehdr *pfh = (struct pingfakehdr *)from;
 601
 602         if (offset == 0) {
 603                 fraglen -= sizeof(struct icmphdr);
 604                 if (fraglen < 0)
 605                         BUG();
 606                 if (!csum_and_copy_from_iter_full(to + sizeof(struct icmphdr),
 607                             fraglen, &pfh->wcheck,
 608                             &pfh->msg->msg_iter))
 609                         return -EFAULT;
 610         } else if (offset < sizeof(struct icmphdr)) {
 611                         BUG();
 612         } else {
 613                 if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
 614                                             &pfh->msg->msg_iter))
 615                         return -EFAULT;
 616         }
 617
 618 #if IS_ENABLED(CONFIG_IPV6)
 619         /* For IPv6, checksum each skb as we go along, as expected by
 620          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 621          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 622          */
 623         if (pfh->family == AF_INET6) {
 624                 skb->csum = pfh->wcheck;
 625                 skb->ip_summed = CHECKSUM_NONE;
 626                 pfh->wcheck = 0;
 627         }
 628 #endif
 629
 630         return 0;
 631 }
 632 EXPORT_SYMBOL_GPL(ping_getfrag);
 633
 634 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 635                                        struct flowi4 *fl4)
 636 {
 637         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 638
 639         if (!skb)
 640                 return 0;
 641         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 642                 sizeof(struct icmphdr), pfh->wcheck);
 643         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 644         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 645         skb->ip_summed = CHECKSUM_NONE;
 646         return ip_push_pending_frames(sk, fl4);
 647 }
 648
 649 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 650                         void *user_icmph, size_t icmph_len) {
 651         u8 type, code;
 652
 653         if (len > 0xFFFF)
 654                 return -EMSGSIZE;
 655
 656         /* Must have at least a full ICMP header. */
 657         if (len < icmph_len)
 658                 return -EINVAL;
 659
 660         /*
 661          *      Check the flags.
 662          */
 663
 664         /* Mirror BSD error message compatibility */
 665         if (msg->msg_flags & MSG_OOB)
 666                 return -EOPNOTSUPP;
 667
 668         /*
 669          *      Fetch the ICMP header provided by the userland.
 670          *      iovec is modified! The ICMP header is consumed.
 671          */
 672         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 673                 return -EFAULT;
 674
 675         if (family == AF_INET) {
 676                 type = ((struct icmphdr *) user_icmph)->type;
 677                 code = ((struct icmphdr *) user_icmph)->code;
 678 #if IS_ENABLED(CONFIG_IPV6)
 679         } else if (family == AF_INET6) {
 680                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 681                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 682 #endif
 683         } else {
 684                 BUG();
 685         }
 686
 687         if (!ping_supported(family, type, code))
 688                 return -EINVAL;
 689
 690         return 0;
 691 }
 692 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 693
 694 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 695 {
 696         struct net *net = sock_net(sk);
 697         struct flowi4 fl4;
 698         struct inet_sock *inet = inet_sk(sk);
 699         struct ipcm_cookie ipc;
 700         struct icmphdr user_icmph;
 701         struct pingfakehdr pfh;
 702         struct rtable *rt = NULL;
 703         struct ip_options_data opt_copy;
 704         int free = 0;
 705         __be32 saddr, daddr, faddr;
 706         u8  tos;
 707         int err;
 708
 709         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 710
 711         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 712                                   sizeof(user_icmph));
 713         if (err)
 714                 return err;
 715
 716         /*
 717          *      Get and verify the address.
 718          */
 719
 720         if (msg->msg_name) {
 721                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 722                 if (msg->msg_namelen < sizeof(*usin))
 723                         return -EINVAL;
 724                 if (usin->sin_family != AF_INET)
 725                         return -EAFNOSUPPORT;
 726                 daddr = usin->sin_addr.s_addr;
 727                 /* no remote port */
 728         } else {
 729                 if (sk->sk_state != TCP_ESTABLISHED)
 730                         return -EDESTADDRREQ;
 731                 daddr = inet->inet_daddr;
 732                 /* no remote port */
 733         }
 734
 735         ipcm_init_sk(&ipc, inet);
 736
 737         if (msg->msg_controllen) {
 738                 err = ip_cmsg_send(sk, msg, &ipc, false);
 739                 if (unlikely(err)) {
 740                         kfree(ipc.opt);
 741                         return err;
 742                 }
 743                 if (ipc.opt)
 744                         free = 1;
 745         }
 746         if (!ipc.opt) {
 747                 struct ip_options_rcu *inet_opt;
 748
 749                 rcu_read_lock();
 750                 inet_opt = rcu_dereference(inet->inet_opt);
 751                 if (inet_opt) {
 752                         memcpy(&opt_copy, inet_opt,
 753                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 754                         ipc.opt = &opt_copy.opt;
 755                 }
 756                 rcu_read_unlock();
 757         }
 758
 759         saddr = ipc.addr;
 760         ipc.addr = faddr = daddr;
 761
 762         if (ipc.opt && ipc.opt->opt.srr) {
 763                 if (!daddr) {
 764                         err = -EINVAL;
 765                         goto out_free;
 766                 }
 767                 faddr = ipc.opt->opt.faddr;
 768         }
 769         tos = get_rttos(&ipc, inet);
 770         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 771             (msg->msg_flags & MSG_DONTROUTE) ||
 772             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 773                 tos |= RTO_ONLINK;
 774         }
 775
 776         if (ipv4_is_multicast(daddr)) {
 777                 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
 778                         ipc.oif = inet->mc_index;
 779                 if (!saddr)
 780                         saddr = inet->mc_addr;
 781         } else if (!ipc.oif)
 782                 ipc.oif = inet->uc_index;
 783
 784         flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos,
 785                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 786                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
 787                            sk->sk_uid);
 788
 789         fl4.fl4_icmp_type = user_icmph.type;
 790         fl4.fl4_icmp_code = user_icmph.code;
 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 out_free:
 836         if (free)
 837                 kfree(ipc.opt);
 838         if (!err) {
 839                 icmp_out_count(sock_net(sk), user_icmph.type);
 840                 return len;
 841         }
 842         return err;
 843
 844 do_confirm:
 845         if (msg->msg_flags & MSG_PROBE)
 846                 dst_confirm_neigh(&rt->dst, &fl4.daddr);
 847         if (!(msg->msg_flags & MSG_PROBE) || len)
 848                 goto back_from_confirm;
 849         err = 0;
 850         goto out;
 851 }
 852
 853 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 854                  int flags, int *addr_len)
 855 {
 856         struct inet_sock *isk = inet_sk(sk);
 857         int family = sk->sk_family;
 858         struct sk_buff *skb;
 859         int copied, err;
 860
 861         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 862
 863         err = -EOPNOTSUPP;
 864         if (flags & MSG_OOB)
 865                 goto out;
 866
 867         if (flags & MSG_ERRQUEUE)
 868                 return inet_recv_error(sk, msg, len, addr_len);
 869
 870         skb = skb_recv_datagram(sk, flags, noblock, &err);
 871         if (!skb)
 872                 goto out;
 873
 874         copied = skb->len;
 875         if (copied > len) {
 876                 msg->msg_flags |= MSG_TRUNC;
 877                 copied = len;
 878         }
 879
 880         /* Don't bother checking the checksum */
 881         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 882         if (err)
 883                 goto done;
 884
 885         sock_recv_timestamp(msg, sk, skb);
 886
 887         /* Copy the address and add cmsg data. */
 888         if (family == AF_INET) {
 889                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 890
 891                 if (sin) {
 892                         sin->sin_family = AF_INET;
 893                         sin->sin_port = 0 /* skb->h.uh->source */;
 894                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 895                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 896                         *addr_len = sizeof(*sin);
 897                 }
 898
 899                 if (isk->cmsg_flags)
 900                         ip_cmsg_recv(msg, skb);
 901
 902 #if IS_ENABLED(CONFIG_IPV6)
 903         } else if (family == AF_INET6) {
 904                 struct ipv6_pinfo *np = inet6_sk(sk);
 905                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 906                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 907
 908                 if (sin6) {
 909                         sin6->sin6_family = AF_INET6;
 910                         sin6->sin6_port = 0;
 911                         sin6->sin6_addr = ip6->saddr;
 912                         sin6->sin6_flowinfo = 0;
 913                         if (np->sndflow)
 914                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 915                         sin6->sin6_scope_id =
 916                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 917                                                     inet6_iif(skb));
 918                         *addr_len = sizeof(*sin6);
 919                 }
 920
 921                 if (inet6_sk(sk)->rxopt.all)
 922                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 923                 if (skb->protocol == htons(ETH_P_IPV6) &&
 924                     inet6_sk(sk)->rxopt.all)
 925                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 926                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 927                         ip_cmsg_recv(msg, skb);
 928 #endif
 929         } else {
 930                 BUG();
 931         }
 932
 933         err = copied;
 934
 935 done:
 936         skb_free_datagram(sk, skb);
 937 out:
 938         pr_debug("ping_recvmsg -> %d\n", err);
 939         return err;
 940 }
 941 EXPORT_SYMBOL_GPL(ping_recvmsg);
 942
 943 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 944 {
 945         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 946                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 947         if (sock_queue_rcv_skb(sk, skb) < 0) {
 948                 kfree_skb(skb);
 949                 pr_debug("ping_queue_rcv_skb -> failed\n");
 950                 return -1;
 951         }
 952         return 0;
 953 }
 954 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 955
 956
 957 /*
 958  *      All we need to do is get the socket.
 959  */
 960
 961 bool ping_rcv(struct sk_buff *skb)
 962 {
 963         struct sock *sk;
 964         struct net *net = dev_net(skb->dev);
 965         struct icmphdr *icmph = icmp_hdr(skb);
 966
 967         /* We assume the packet has already been checked by icmp_rcv */
 968
 969         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 970                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 971
 972         /* Push ICMP header back */
 973         skb_push(skb, skb->data - (u8 *)icmph);
 974
 975         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 976         if (sk) {
 977                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 978
 979                 pr_debug("rcv on socket %p\n", sk);
 980                 if (skb2)
 981                         ping_queue_rcv_skb(sk, skb2);
 982                 sock_put(sk);
 983                 return true;
 984         }
 985         pr_debug("no socket, dropping\n");
 986
 987         return false;
 988 }
 989 EXPORT_SYMBOL_GPL(ping_rcv);
 990
 991 struct proto ping_prot = {
 992         .name =         "PING",
 993         .owner =        THIS_MODULE,
 994         .init =         ping_init_sock,
 995         .close =        ping_close,
 996         .connect =      ip4_datagram_connect,
 997         .disconnect =   __udp_disconnect,
 998         .setsockopt =   ip_setsockopt,
 999         .getsockopt =   ip_getsockopt,
1000         .sendmsg =      ping_v4_sendmsg,
1001         .recvmsg =      ping_recvmsg,
1002         .bind =         ping_bind,
1003         .backlog_rcv =  ping_queue_rcv_skb,
1004         .release_cb =   ip4_datagram_release_cb,
1005         .hash =         ping_hash,
1006         .unhash =       ping_unhash,
1007         .get_port =     ping_get_port,
1008         .obj_size =     sizeof(struct inet_sock),
1009 };
1010 EXPORT_SYMBOL(ping_prot);
1011
1012 #ifdef CONFIG_PROC_FS
1013
1014 static struct sock *ping_get_first(struct seq_file *seq, int start)
1015 {
1016         struct sock *sk;
1017         struct ping_iter_state *state = seq->private;
1018         struct net *net = seq_file_net(seq);
1019
1020         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1021              ++state->bucket) {
1022                 struct hlist_nulls_node *node;
1023                 struct hlist_nulls_head *hslot;
1024
1025                 hslot = &ping_table.hash[state->bucket];
1026
1027                 if (hlist_nulls_empty(hslot))
1028                         continue;
1029
1030                 sk_nulls_for_each(sk, node, hslot) {
1031                         if (net_eq(sock_net(sk), net) &&
1032                             sk->sk_family == state->family)
1033                                 goto found;
1034                 }
1035         }
1036         sk = NULL;
1037 found:
1038         return sk;
1039 }
1040
1041 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1042 {
1043         struct ping_iter_state *state = seq->private;
1044         struct net *net = seq_file_net(seq);
1045
1046         do {
1047                 sk = sk_nulls_next(sk);
1048         } while (sk && (!net_eq(sock_net(sk), net)));
1049
1050         if (!sk)
1051                 return ping_get_first(seq, state->bucket + 1);
1052         return sk;
1053 }
1054
1055 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1056 {
1057         struct sock *sk = ping_get_first(seq, 0);
1058
1059         if (sk)
1060                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1061                         --pos;
1062         return pos ? NULL : sk;
1063 }
1064
1065 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1066         __acquires(ping_table.lock)
1067 {
1068         struct ping_iter_state *state = seq->private;
1069         state->bucket = 0;
1070         state->family = family;
1071
1072         read_lock_bh(&ping_table.lock);
1073
1074         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1075 }
1076 EXPORT_SYMBOL_GPL(ping_seq_start);
1077
1078 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1079 {
1080         return ping_seq_start(seq, pos, AF_INET);
1081 }
1082
1083 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1084 {
1085         struct sock *sk;
1086
1087         if (v == SEQ_START_TOKEN)
1088                 sk = ping_get_idx(seq, 0);
1089         else
1090                 sk = ping_get_next(seq, v);
1091
1092         ++*pos;
1093         return sk;
1094 }
1095 EXPORT_SYMBOL_GPL(ping_seq_next);
1096
1097 void ping_seq_stop(struct seq_file *seq, void *v)
1098         __releases(ping_table.lock)
1099 {
1100         read_unlock_bh(&ping_table.lock);
1101 }
1102 EXPORT_SYMBOL_GPL(ping_seq_stop);
1103
1104 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1105                 int bucket)
1106 {
1107         struct inet_sock *inet = inet_sk(sp);
1108         __be32 dest = inet->inet_daddr;
1109         __be32 src = inet->inet_rcv_saddr;
1110         __u16 destp = ntohs(inet->inet_dport);
1111         __u16 srcp = ntohs(inet->inet_sport);
1112
1113         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1114                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
1115                 bucket, src, srcp, dest, destp, sp->sk_state,
1116                 sk_wmem_alloc_get(sp),
1117                 sk_rmem_alloc_get(sp),
1118                 0, 0L, 0,
1119                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1120                 0, sock_i_ino(sp),
1121                 refcount_read(&sp->sk_refcnt), sp,
1122                 atomic_read(&sp->sk_drops));
1123 }
1124
1125 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1126 {
1127         seq_setwidth(seq, 127);
1128         if (v == SEQ_START_TOKEN)
1129                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1130                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1131                            "inode ref pointer drops");
1132         else {
1133                 struct ping_iter_state *state = seq->private;
1134
1135                 ping_v4_format_sock(v, seq, state->bucket);
1136         }
1137         seq_pad(seq, '\n');
1138         return 0;
1139 }
1140
1141 static const struct seq_operations ping_v4_seq_ops = {
1142         .start          = ping_v4_seq_start,
1143         .show           = ping_v4_seq_show,
1144         .next           = ping_seq_next,
1145         .stop           = ping_seq_stop,
1146 };
1147
1148 static int __net_init ping_v4_proc_init_net(struct net *net)
1149 {
1150         if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
1151                         sizeof(struct ping_iter_state)))
1152                 return -ENOMEM;
1153         return 0;
1154 }
1155
1156 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1157 {
1158         remove_proc_entry("icmp", net->proc_net);
1159 }
1160
1161 static struct pernet_operations ping_v4_net_ops = {
1162         .init = ping_v4_proc_init_net,
1163         .exit = ping_v4_proc_exit_net,
1164 };
1165
1166 int __init ping_proc_init(void)
1167 {
1168         return register_pernet_subsys(&ping_v4_net_ops);
1169 }
1170
1171 void ping_proc_exit(void)
1172 {
1173         unregister_pernet_subsys(&ping_v4_net_ops);
1174 }
1175
1176 #endif
1177
1178 void __init ping_init(void)
1179 {
1180         int i;
1181
1182         for (i = 0; i < PING_HTABLE_SIZE; i++)
1183                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1184         rwlock_init(&ping_table.lock);
1185 }