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 {
 298         struct net *net = sock_net(sk);
 299         if (sk->sk_family == AF_INET) {
 300                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 301                 int chk_addr_ret;
 302
 303                 if (addr_len < sizeof(*addr))
 304                         return -EINVAL;
 305
 306                 if (addr->sin_family != AF_INET &&
 307                     !(addr->sin_family == AF_UNSPEC &&
 308                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 309                         return -EAFNOSUPPORT;
 310
 311                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 312                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 313
 314                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 315                         chk_addr_ret = RTN_LOCAL;
 316                 else
 317                         chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
 318
 319                 if ((!inet_can_nonlocal_bind(net, isk) &&
 320                      chk_addr_ret != RTN_LOCAL) ||
 321                     chk_addr_ret == RTN_MULTICAST ||
 322                     chk_addr_ret == RTN_BROADCAST)
 323                         return -EADDRNOTAVAIL;
 324
 325 #if IS_ENABLED(CONFIG_IPV6)
 326         } else if (sk->sk_family == AF_INET6) {
 327                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 328                 int addr_type, scoped, has_addr;
 329                 struct net_device *dev = NULL;
 330
 331                 if (addr_len < sizeof(*addr))
 332                         return -EINVAL;
 333
 334                 if (addr->sin6_family != AF_INET6)
 335                         return -EAFNOSUPPORT;
 336
 337                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 338                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 339
 340                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 341                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 342                 if ((addr_type != IPV6_ADDR_ANY &&
 343                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 344                     (scoped && !addr->sin6_scope_id))
 345                         return -EINVAL;
 346
 347                 rcu_read_lock();
 348                 if (addr->sin6_scope_id) {
 349                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 350                         if (!dev) {
 351                                 rcu_read_unlock();
 352                                 return -ENODEV;
 353                         }
 354                 }
 355                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 356                                                     scoped);
 357                 rcu_read_unlock();
 358
 359                 if (!(ipv6_can_nonlocal_bind(net, isk) || has_addr ||
 360                       addr_type == IPV6_ADDR_ANY))
 361                         return -EADDRNOTAVAIL;
 362
 363                 if (scoped)
 364                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 365 #endif
 366         } else {
 367                 return -EAFNOSUPPORT;
 368         }
 369         return 0;
 370 }
 371
 372 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 373 {
 374         if (saddr->sa_family == AF_INET) {
 375                 struct inet_sock *isk = inet_sk(sk);
 376                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 377                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 378 #if IS_ENABLED(CONFIG_IPV6)
 379         } else if (saddr->sa_family == AF_INET6) {
 380                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 381                 struct ipv6_pinfo *np = inet6_sk(sk);
 382                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 383 #endif
 384         }
 385 }
 386
 387 /*
 388  * We need our own bind because there are no privileged id's == local ports.
 389  * Moreover, we don't allow binding to multi- and broadcast addresses.
 390  */
 391
 392 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 393 {
 394         struct inet_sock *isk = inet_sk(sk);
 395         unsigned short snum;
 396         int err;
 397         int dif = sk->sk_bound_dev_if;
 398
 399         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 400         if (err)
 401                 return err;
 402
 403         lock_sock(sk);
 404
 405         err = -EINVAL;
 406         if (isk->inet_num != 0)
 407                 goto out;
 408
 409         err = -EADDRINUSE;
 410         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 411         if (ping_get_port(sk, snum) != 0) {
 412                 /* Restore possibly modified sk->sk_bound_dev_if by ping_check_bind_addr(). */
 413                 sk->sk_bound_dev_if = dif;
 414                 goto out;
 415         }
 416         ping_set_saddr(sk, uaddr);
 417
 418         pr_debug("after bind(): num = %hu, dif = %d\n",
 419                  isk->inet_num,
 420                  sk->sk_bound_dev_if);
 421
 422         err = 0;
 423         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 424                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 425 #if IS_ENABLED(CONFIG_IPV6)
 426         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 427                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 428 #endif
 429
 430         if (snum)
 431                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 432         isk->inet_sport = htons(isk->inet_num);
 433         isk->inet_daddr = 0;
 434         isk->inet_dport = 0;
 435
 436 #if IS_ENABLED(CONFIG_IPV6)
 437         if (sk->sk_family == AF_INET6)
 438                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 439 #endif
 440
 441         sk_dst_reset(sk);
 442 out:
 443         release_sock(sk);
 444         pr_debug("ping_v4_bind -> %d\n", err);
 445         return err;
 446 }
 447 EXPORT_SYMBOL_GPL(ping_bind);
 448
 449 /*
 450  * Is this a supported type of ICMP message?
 451  */
 452
 453 static inline int ping_supported(int family, int type, int code)
 454 {
 455         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 456                (family == AF_INET && type == ICMP_EXT_ECHO && code == 0) ||
 457                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0) ||
 458                (family == AF_INET6 && type == ICMPV6_EXT_ECHO_REQUEST && code == 0);
 459 }
 460
 461 /*
 462  * This routine is called by the ICMP module when it gets some
 463  * sort of error condition.
 464  */
 465
 466 void ping_err(struct sk_buff *skb, int offset, u32 info)
 467 {
 468         int family;
 469         struct icmphdr *icmph;
 470         struct inet_sock *inet_sock;
 471         int type;
 472         int code;
 473         struct net *net = dev_net(skb->dev);
 474         struct sock *sk;
 475         int harderr;
 476         int err;
 477
 478         if (skb->protocol == htons(ETH_P_IP)) {
 479                 family = AF_INET;
 480                 type = icmp_hdr(skb)->type;
 481                 code = icmp_hdr(skb)->code;
 482                 icmph = (struct icmphdr *)(skb->data + offset);
 483         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 484                 family = AF_INET6;
 485                 type = icmp6_hdr(skb)->icmp6_type;
 486                 code = icmp6_hdr(skb)->icmp6_code;
 487                 icmph = (struct icmphdr *) (skb->data + offset);
 488         } else {
 489                 BUG();
 490         }
 491
 492         /* We assume the packet has already been checked by icmp_unreach */
 493
 494         if (!ping_supported(family, icmph->type, icmph->code))
 495                 return;
 496
 497         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 498                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 499                  ntohs(icmph->un.echo.sequence));
 500
 501         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 502         if (!sk) {
 503                 pr_debug("no socket, dropping\n");
 504                 return; /* No socket for error */
 505         }
 506         pr_debug("err on socket %p\n", sk);
 507
 508         err = 0;
 509         harderr = 0;
 510         inet_sock = inet_sk(sk);
 511
 512         if (skb->protocol == htons(ETH_P_IP)) {
 513                 switch (type) {
 514                 default:
 515                 case ICMP_TIME_EXCEEDED:
 516                         err = EHOSTUNREACH;
 517                         break;
 518                 case ICMP_SOURCE_QUENCH:
 519                         /* This is not a real error but ping wants to see it.
 520                          * Report it with some fake errno.
 521                          */
 522                         err = EREMOTEIO;
 523                         break;
 524                 case ICMP_PARAMETERPROB:
 525                         err = EPROTO;
 526                         harderr = 1;
 527                         break;
 528                 case ICMP_DEST_UNREACH:
 529                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 530                                 ipv4_sk_update_pmtu(skb, sk, info);
 531                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 532                                         err = EMSGSIZE;
 533                                         harderr = 1;
 534                                         break;
 535                                 }
 536                                 goto out;
 537                         }
 538                         err = EHOSTUNREACH;
 539                         if (code <= NR_ICMP_UNREACH) {
 540                                 harderr = icmp_err_convert[code].fatal;
 541                                 err = icmp_err_convert[code].errno;
 542                         }
 543                         break;
 544                 case ICMP_REDIRECT:
 545                         /* See ICMP_SOURCE_QUENCH */
 546                         ipv4_sk_redirect(skb, sk);
 547                         err = EREMOTEIO;
 548                         break;
 549                 }
 550 #if IS_ENABLED(CONFIG_IPV6)
 551         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 552                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 553 #endif
 554         }
 555
 556         /*
 557          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 558          *      4.1.3.3.
 559          */
 560         if ((family == AF_INET && !inet_sock->recverr) ||
 561             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 562                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 563                         goto out;
 564         } else {
 565                 if (family == AF_INET) {
 566                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 567                                       info, (u8 *)icmph);
 568 #if IS_ENABLED(CONFIG_IPV6)
 569                 } else if (family == AF_INET6) {
 570                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 571                                                    info, (u8 *)icmph);
 572 #endif
 573                 }
 574         }
 575         sk->sk_err = err;
 576         sk->sk_error_report(sk);
 577 out:
 578         sock_put(sk);
 579 }
 580 EXPORT_SYMBOL_GPL(ping_err);
 581
 582 /*
 583  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 584  *      starting from the payload.
 585  */
 586
 587 int ping_getfrag(void *from, char *to,
 588                  int offset, int fraglen, int odd, struct sk_buff *skb)
 589 {
 590         struct pingfakehdr *pfh = (struct pingfakehdr *)from;
 591
 592         if (offset == 0) {
 593                 fraglen -= sizeof(struct icmphdr);
 594                 if (fraglen < 0)
 595                         BUG();
 596                 if (!csum_and_copy_from_iter_full(to + sizeof(struct icmphdr),
 597                             fraglen, &pfh->wcheck,
 598                             &pfh->msg->msg_iter))
 599                         return -EFAULT;
 600         } else if (offset < sizeof(struct icmphdr)) {
 601                         BUG();
 602         } else {
 603                 if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
 604                                             &pfh->msg->msg_iter))
 605                         return -EFAULT;
 606         }
 607
 608 #if IS_ENABLED(CONFIG_IPV6)
 609         /* For IPv6, checksum each skb as we go along, as expected by
 610          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 611          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 612          */
 613         if (pfh->family == AF_INET6) {
 614                 skb->csum = pfh->wcheck;
 615                 skb->ip_summed = CHECKSUM_NONE;
 616                 pfh->wcheck = 0;
 617         }
 618 #endif
 619
 620         return 0;
 621 }
 622 EXPORT_SYMBOL_GPL(ping_getfrag);
 623
 624 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 625                                        struct flowi4 *fl4)
 626 {
 627         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 628
 629         if (!skb)
 630                 return 0;
 631         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 632                 sizeof(struct icmphdr), pfh->wcheck);
 633         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 634         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 635         skb->ip_summed = CHECKSUM_NONE;
 636         return ip_push_pending_frames(sk, fl4);
 637 }
 638
 639 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 640                         void *user_icmph, size_t icmph_len)
 641 {
 642         u8 type, code;
 643
 644         if (len > 0xFFFF)
 645                 return -EMSGSIZE;
 646
 647         /* Must have at least a full ICMP header. */
 648         if (len < icmph_len)
 649                 return -EINVAL;
 650
 651         /*
 652          *      Check the flags.
 653          */
 654
 655         /* Mirror BSD error message compatibility */
 656         if (msg->msg_flags & MSG_OOB)
 657                 return -EOPNOTSUPP;
 658
 659         /*
 660          *      Fetch the ICMP header provided by the userland.
 661          *      iovec is modified! The ICMP header is consumed.
 662          */
 663         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 664                 return -EFAULT;
 665
 666         if (family == AF_INET) {
 667                 type = ((struct icmphdr *) user_icmph)->type;
 668                 code = ((struct icmphdr *) user_icmph)->code;
 669 #if IS_ENABLED(CONFIG_IPV6)
 670         } else if (family == AF_INET6) {
 671                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 672                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 673 #endif
 674         } else {
 675                 BUG();
 676         }
 677
 678         if (!ping_supported(family, type, code))
 679                 return -EINVAL;
 680
 681         return 0;
 682 }
 683 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 684
 685 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 686 {
 687         struct net *net = sock_net(sk);
 688         struct flowi4 fl4;
 689         struct inet_sock *inet = inet_sk(sk);
 690         struct ipcm_cookie ipc;
 691         struct icmphdr user_icmph;
 692         struct pingfakehdr pfh;
 693         struct rtable *rt = NULL;
 694         struct ip_options_data opt_copy;
 695         int free = 0;
 696         __be32 saddr, daddr, faddr;
 697         u8  tos;
 698         int err;
 699
 700         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 701
 702         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 703                                   sizeof(user_icmph));
 704         if (err)
 705                 return err;
 706
 707         /*
 708          *      Get and verify the address.
 709          */
 710
 711         if (msg->msg_name) {
 712                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 713                 if (msg->msg_namelen < sizeof(*usin))
 714                         return -EINVAL;
 715                 if (usin->sin_family != AF_INET)
 716                         return -EAFNOSUPPORT;
 717                 daddr = usin->sin_addr.s_addr;
 718                 /* no remote port */
 719         } else {
 720                 if (sk->sk_state != TCP_ESTABLISHED)
 721                         return -EDESTADDRREQ;
 722                 daddr = inet->inet_daddr;
 723                 /* no remote port */
 724         }
 725
 726         ipcm_init_sk(&ipc, inet);
 727
 728         if (msg->msg_controllen) {
 729                 err = ip_cmsg_send(sk, msg, &ipc, false);
 730                 if (unlikely(err)) {
 731                         kfree(ipc.opt);
 732                         return err;
 733                 }
 734                 if (ipc.opt)
 735                         free = 1;
 736         }
 737         if (!ipc.opt) {
 738                 struct ip_options_rcu *inet_opt;
 739
 740                 rcu_read_lock();
 741                 inet_opt = rcu_dereference(inet->inet_opt);
 742                 if (inet_opt) {
 743                         memcpy(&opt_copy, inet_opt,
 744                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 745                         ipc.opt = &opt_copy.opt;
 746                 }
 747                 rcu_read_unlock();
 748         }
 749
 750         saddr = ipc.addr;
 751         ipc.addr = faddr = daddr;
 752
 753         if (ipc.opt && ipc.opt->opt.srr) {
 754                 if (!daddr) {
 755                         err = -EINVAL;
 756                         goto out_free;
 757                 }
 758                 faddr = ipc.opt->opt.faddr;
 759         }
 760         tos = get_rttos(&ipc, inet);
 761         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 762             (msg->msg_flags & MSG_DONTROUTE) ||
 763             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 764                 tos |= RTO_ONLINK;
 765         }
 766
 767         if (ipv4_is_multicast(daddr)) {
 768                 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
 769                         ipc.oif = inet->mc_index;
 770                 if (!saddr)
 771                         saddr = inet->mc_addr;
 772         } else if (!ipc.oif)
 773                 ipc.oif = inet->uc_index;
 774
 775         flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos,
 776                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 777                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
 778                            sk->sk_uid);
 779
 780         fl4.fl4_icmp_type = user_icmph.type;
 781         fl4.fl4_icmp_code = user_icmph.code;
 782
 783         security_sk_classify_flow(sk, flowi4_to_flowi_common(&fl4));
 784         rt = ip_route_output_flow(net, &fl4, sk);
 785         if (IS_ERR(rt)) {
 786                 err = PTR_ERR(rt);
 787                 rt = NULL;
 788                 if (err == -ENETUNREACH)
 789                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 790                 goto out;
 791         }
 792
 793         err = -EACCES;
 794         if ((rt->rt_flags & RTCF_BROADCAST) &&
 795             !sock_flag(sk, SOCK_BROADCAST))
 796                 goto out;
 797
 798         if (msg->msg_flags & MSG_CONFIRM)
 799                 goto do_confirm;
 800 back_from_confirm:
 801
 802         if (!ipc.addr)
 803                 ipc.addr = fl4.daddr;
 804
 805         lock_sock(sk);
 806
 807         pfh.icmph.type = user_icmph.type; /* already checked */
 808         pfh.icmph.code = user_icmph.code; /* ditto */
 809         pfh.icmph.checksum = 0;
 810         pfh.icmph.un.echo.id = inet->inet_sport;
 811         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 812         pfh.msg = msg;
 813         pfh.wcheck = 0;
 814         pfh.family = AF_INET;
 815
 816         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 817                         0, &ipc, &rt, msg->msg_flags);
 818         if (err)
 819                 ip_flush_pending_frames(sk);
 820         else
 821                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 822         release_sock(sk);
 823
 824 out:
 825         ip_rt_put(rt);
 826 out_free:
 827         if (free)
 828                 kfree(ipc.opt);
 829         if (!err) {
 830                 icmp_out_count(sock_net(sk), user_icmph.type);
 831                 return len;
 832         }
 833         return err;
 834
 835 do_confirm:
 836         if (msg->msg_flags & MSG_PROBE)
 837                 dst_confirm_neigh(&rt->dst, &fl4.daddr);
 838         if (!(msg->msg_flags & MSG_PROBE) || len)
 839                 goto back_from_confirm;
 840         err = 0;
 841         goto out;
 842 }
 843
 844 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 845                  int flags, int *addr_len)
 846 {
 847         struct inet_sock *isk = inet_sk(sk);
 848         int family = sk->sk_family;
 849         struct sk_buff *skb;
 850         int copied, err;
 851
 852         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 853
 854         err = -EOPNOTSUPP;
 855         if (flags & MSG_OOB)
 856                 goto out;
 857
 858         if (flags & MSG_ERRQUEUE)
 859                 return inet_recv_error(sk, msg, len, addr_len);
 860
 861         skb = skb_recv_datagram(sk, flags, noblock, &err);
 862         if (!skb)
 863                 goto out;
 864
 865         copied = skb->len;
 866         if (copied > len) {
 867                 msg->msg_flags |= MSG_TRUNC;
 868                 copied = len;
 869         }
 870
 871         /* Don't bother checking the checksum */
 872         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 873         if (err)
 874                 goto done;
 875
 876         sock_recv_timestamp(msg, sk, skb);
 877
 878         /* Copy the address and add cmsg data. */
 879         if (family == AF_INET) {
 880                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 881
 882                 if (sin) {
 883                         sin->sin_family = AF_INET;
 884                         sin->sin_port = 0 /* skb->h.uh->source */;
 885                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 886                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 887                         *addr_len = sizeof(*sin);
 888                 }
 889
 890                 if (isk->cmsg_flags)
 891                         ip_cmsg_recv(msg, skb);
 892
 893 #if IS_ENABLED(CONFIG_IPV6)
 894         } else if (family == AF_INET6) {
 895                 struct ipv6_pinfo *np = inet6_sk(sk);
 896                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 897                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 898
 899                 if (sin6) {
 900                         sin6->sin6_family = AF_INET6;
 901                         sin6->sin6_port = 0;
 902                         sin6->sin6_addr = ip6->saddr;
 903                         sin6->sin6_flowinfo = 0;
 904                         if (np->sndflow)
 905                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 906                         sin6->sin6_scope_id =
 907                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 908                                                     inet6_iif(skb));
 909                         *addr_len = sizeof(*sin6);
 910                 }
 911
 912                 if (inet6_sk(sk)->rxopt.all)
 913                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 914                 if (skb->protocol == htons(ETH_P_IPV6) &&
 915                     inet6_sk(sk)->rxopt.all)
 916                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 917                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 918                         ip_cmsg_recv(msg, skb);
 919 #endif
 920         } else {
 921                 BUG();
 922         }
 923
 924         err = copied;
 925
 926 done:
 927         skb_free_datagram(sk, skb);
 928 out:
 929         pr_debug("ping_recvmsg -> %d\n", err);
 930         return err;
 931 }
 932 EXPORT_SYMBOL_GPL(ping_recvmsg);
 933
 934 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 935 {
 936         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 937                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 938         if (sock_queue_rcv_skb(sk, skb) < 0) {
 939                 kfree_skb(skb);
 940                 pr_debug("ping_queue_rcv_skb -> failed\n");
 941                 return -1;
 942         }
 943         return 0;
 944 }
 945 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 946
 947
 948 /*
 949  *      All we need to do is get the socket.
 950  */
 951
 952 bool ping_rcv(struct sk_buff *skb)
 953 {
 954         struct sock *sk;
 955         struct net *net = dev_net(skb->dev);
 956         struct icmphdr *icmph = icmp_hdr(skb);
 957         bool rc = false;
 958
 959         /* We assume the packet has already been checked by icmp_rcv */
 960
 961         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 962                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 963
 964         /* Push ICMP header back */
 965         skb_push(skb, skb->data - (u8 *)icmph);
 966
 967         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 968         if (sk) {
 969                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 970
 971                 pr_debug("rcv on socket %p\n", sk);
 972                 if (skb2 && !ping_queue_rcv_skb(sk, skb2))
 973                         rc = true;
 974                 sock_put(sk);
 975         }
 976
 977         if (!rc)
 978                 pr_debug("no socket, dropping\n");
 979
 980         return rc;
 981 }
 982 EXPORT_SYMBOL_GPL(ping_rcv);
 983
 984 struct proto ping_prot = {
 985         .name =         "PING",
 986         .owner =        THIS_MODULE,
 987         .init =         ping_init_sock,
 988         .close =        ping_close,
 989         .connect =      ip4_datagram_connect,
 990         .disconnect =   __udp_disconnect,
 991         .setsockopt =   ip_setsockopt,
 992         .getsockopt =   ip_getsockopt,
 993         .sendmsg =      ping_v4_sendmsg,
 994         .recvmsg =      ping_recvmsg,
 995         .bind =         ping_bind,
 996         .backlog_rcv =  ping_queue_rcv_skb,
 997         .release_cb =   ip4_datagram_release_cb,
 998         .hash =         ping_hash,
 999         .unhash =       ping_unhash,
1000         .get_port =     ping_get_port,
1001         .obj_size =     sizeof(struct inet_sock),
1002 };
1003 EXPORT_SYMBOL(ping_prot);
1004
1005 #ifdef CONFIG_PROC_FS
1006
1007 static struct sock *ping_get_first(struct seq_file *seq, int start)
1008 {
1009         struct sock *sk;
1010         struct ping_iter_state *state = seq->private;
1011         struct net *net = seq_file_net(seq);
1012
1013         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1014              ++state->bucket) {
1015                 struct hlist_nulls_node *node;
1016                 struct hlist_nulls_head *hslot;
1017
1018                 hslot = &ping_table.hash[state->bucket];
1019
1020                 if (hlist_nulls_empty(hslot))
1021                         continue;
1022
1023                 sk_nulls_for_each(sk, node, hslot) {
1024                         if (net_eq(sock_net(sk), net) &&
1025                             sk->sk_family == state->family)
1026                                 goto found;
1027                 }
1028         }
1029         sk = NULL;
1030 found:
1031         return sk;
1032 }
1033
1034 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1035 {
1036         struct ping_iter_state *state = seq->private;
1037         struct net *net = seq_file_net(seq);
1038
1039         do {
1040                 sk = sk_nulls_next(sk);
1041         } while (sk && (!net_eq(sock_net(sk), net)));
1042
1043         if (!sk)
1044                 return ping_get_first(seq, state->bucket + 1);
1045         return sk;
1046 }
1047
1048 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1049 {
1050         struct sock *sk = ping_get_first(seq, 0);
1051
1052         if (sk)
1053                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1054                         --pos;
1055         return pos ? NULL : sk;
1056 }
1057
1058 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1059         __acquires(ping_table.lock)
1060 {
1061         struct ping_iter_state *state = seq->private;
1062         state->bucket = 0;
1063         state->family = family;
1064
1065         read_lock_bh(&ping_table.lock);
1066
1067         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1068 }
1069 EXPORT_SYMBOL_GPL(ping_seq_start);
1070
1071 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1072 {
1073         return ping_seq_start(seq, pos, AF_INET);
1074 }
1075
1076 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1077 {
1078         struct sock *sk;
1079
1080         if (v == SEQ_START_TOKEN)
1081                 sk = ping_get_idx(seq, 0);
1082         else
1083                 sk = ping_get_next(seq, v);
1084
1085         ++*pos;
1086         return sk;
1087 }
1088 EXPORT_SYMBOL_GPL(ping_seq_next);
1089
1090 void ping_seq_stop(struct seq_file *seq, void *v)
1091         __releases(ping_table.lock)
1092 {
1093         read_unlock_bh(&ping_table.lock);
1094 }
1095 EXPORT_SYMBOL_GPL(ping_seq_stop);
1096
1097 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1098                 int bucket)
1099 {
1100         struct inet_sock *inet = inet_sk(sp);
1101         __be32 dest = inet->inet_daddr;
1102         __be32 src = inet->inet_rcv_saddr;
1103         __u16 destp = ntohs(inet->inet_dport);
1104         __u16 srcp = ntohs(inet->inet_sport);
1105
1106         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1107                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
1108                 bucket, src, srcp, dest, destp, sp->sk_state,
1109                 sk_wmem_alloc_get(sp),
1110                 sk_rmem_alloc_get(sp),
1111                 0, 0L, 0,
1112                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1113                 0, sock_i_ino(sp),
1114                 refcount_read(&sp->sk_refcnt), sp,
1115                 atomic_read(&sp->sk_drops));
1116 }
1117
1118 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1119 {
1120         seq_setwidth(seq, 127);
1121         if (v == SEQ_START_TOKEN)
1122                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1123                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1124                            "inode ref pointer drops");
1125         else {
1126                 struct ping_iter_state *state = seq->private;
1127
1128                 ping_v4_format_sock(v, seq, state->bucket);
1129         }
1130         seq_pad(seq, '\n');
1131         return 0;
1132 }
1133
1134 static const struct seq_operations ping_v4_seq_ops = {
1135         .start          = ping_v4_seq_start,
1136         .show           = ping_v4_seq_show,
1137         .next           = ping_seq_next,
1138         .stop           = ping_seq_stop,
1139 };
1140
1141 static int __net_init ping_v4_proc_init_net(struct net *net)
1142 {
1143         if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
1144                         sizeof(struct ping_iter_state)))
1145                 return -ENOMEM;
1146         return 0;
1147 }
1148
1149 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1150 {
1151         remove_proc_entry("icmp", net->proc_net);
1152 }
1153
1154 static struct pernet_operations ping_v4_net_ops = {
1155         .init = ping_v4_proc_init_net,
1156         .exit = ping_v4_proc_exit_net,
1157 };
1158
1159 int __init ping_proc_init(void)
1160 {
1161         return register_pernet_subsys(&ping_v4_net_ops);
1162 }
1163
1164 void ping_proc_exit(void)
1165 {
1166         unregister_pernet_subsys(&ping_v4_net_ops);
1167 }
1168
1169 #endif
1170
1171 void __init ping_init(void)
1172 {
1173         int i;
1174
1175         for (i = 0; i < PING_HTABLE_SIZE; i++)
1176                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1177         rwlock_init(&ping_table.lock);
1178 }