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 <linux/bpf-cgroup.h>
  37 #include <net/sock.h>
  38 #include <net/ping.h>
  39 #include <net/udp.h>
  40 #include <net/route.h>
  41 #include <net/inet_common.h>
  42 #include <net/checksum.h>
  43
  44 #if IS_ENABLED(CONFIG_IPV6)
  45 #include <linux/in6.h>
  46 #include <linux/icmpv6.h>
  47 #include <net/addrconf.h>
  48 #include <net/ipv6.h>
  49 #include <net/transp_v6.h>
  50 #endif
  51
  52 struct ping_table {
  53         struct hlist_nulls_head hash[PING_HTABLE_SIZE];
  54         spinlock_t              lock;
  55 };
  56
  57 static struct ping_table ping_table;
  58 struct pingv6_ops pingv6_ops;
  59 EXPORT_SYMBOL_GPL(pingv6_ops);
  60
  61 static u16 ping_port_rover;
  62
  63 static inline u32 ping_hashfn(const struct net *net, u32 num, u32 mask)
  64 {
  65         u32 res = (num + net_hash_mix(net)) & mask;
  66
  67         pr_debug("hash(%u) = %u\n", num, res);
  68         return res;
  69 }
  70 EXPORT_SYMBOL_GPL(ping_hash);
  71
  72 static inline struct hlist_nulls_head *ping_hashslot(struct ping_table *table,
  73                                              struct net *net, unsigned int num)
  74 {
  75         return &table->hash[ping_hashfn(net, num, PING_HTABLE_MASK)];
  76 }
  77
  78 int ping_get_port(struct sock *sk, unsigned short ident)
  79 {
  80         struct hlist_nulls_node *node;
  81         struct hlist_nulls_head *hlist;
  82         struct inet_sock *isk, *isk2;
  83         struct sock *sk2 = NULL;
  84
  85         isk = inet_sk(sk);
  86         spin_lock(&ping_table.lock);
  87         if (ident == 0) {
  88                 u32 i;
  89                 u16 result = ping_port_rover + 1;
  90
  91                 for (i = 0; i < (1L << 16); i++, result++) {
  92                         if (!result)
  93                                 result++; /* avoid zero */
  94                         hlist = ping_hashslot(&ping_table, sock_net(sk),
  95                                             result);
  96                         ping_portaddr_for_each_entry(sk2, node, hlist) {
  97                                 isk2 = inet_sk(sk2);
  98
  99                                 if (isk2->inet_num == result)
 100                                         goto next_port;
 101                         }
 102
 103                         /* found */
 104                         ping_port_rover = ident = result;
 105                         break;
 106 next_port:
 107                         ;
 108                 }
 109                 if (i >= (1L << 16))
 110                         goto fail;
 111         } else {
 112                 hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
 113                 ping_portaddr_for_each_entry(sk2, node, hlist) {
 114                         isk2 = inet_sk(sk2);
 115
 116                         /* BUG? Why is this reuse and not reuseaddr? ping.c
 117                          * doesn't turn off SO_REUSEADDR, and it doesn't expect
 118                          * that other ping processes can steal its packets.
 119                          */
 120                         if ((isk2->inet_num == ident) &&
 121                             (sk2 != sk) &&
 122                             (!sk2->sk_reuse || !sk->sk_reuse))
 123                                 goto fail;
 124                 }
 125         }
 126
 127         pr_debug("found port/ident = %d\n", ident);
 128         isk->inet_num = ident;
 129         if (sk_unhashed(sk)) {
 130                 pr_debug("was not hashed\n");
 131                 sock_hold(sk);
 132                 sock_set_flag(sk, SOCK_RCU_FREE);
 133                 hlist_nulls_add_head_rcu(&sk->sk_nulls_node, hlist);
 134                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 135         }
 136         spin_unlock(&ping_table.lock);
 137         return 0;
 138
 139 fail:
 140         spin_unlock(&ping_table.lock);
 141         return 1;
 142 }
 143 EXPORT_SYMBOL_GPL(ping_get_port);
 144
 145 int ping_hash(struct sock *sk)
 146 {
 147         pr_debug("ping_hash(sk->port=%u)\n", inet_sk(sk)->inet_num);
 148         BUG(); /* "Please do not press this button again." */
 149
 150         return 0;
 151 }
 152
 153 void ping_unhash(struct sock *sk)
 154 {
 155         struct inet_sock *isk = inet_sk(sk);
 156
 157         pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
 158         spin_lock(&ping_table.lock);
 159         if (sk_hashed(sk)) {
 160                 hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
 161                 sock_put(sk);
 162                 isk->inet_num = 0;
 163                 isk->inet_sport = 0;
 164                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 165         }
 166         spin_unlock(&ping_table.lock);
 167 }
 168 EXPORT_SYMBOL_GPL(ping_unhash);
 169
 170 /* Called under rcu_read_lock() */
 171 static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 172 {
 173         struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
 174         struct sock *sk = NULL;
 175         struct inet_sock *isk;
 176         struct hlist_nulls_node *hnode;
 177         int dif, sdif;
 178
 179         if (skb->protocol == htons(ETH_P_IP)) {
 180                 dif = inet_iif(skb);
 181                 sdif = inet_sdif(skb);
 182                 pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
 183                          (int)ident, &ip_hdr(skb)->daddr, dif);
 184 #if IS_ENABLED(CONFIG_IPV6)
 185         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 186                 dif = inet6_iif(skb);
 187                 sdif = inet6_sdif(skb);
 188                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 189                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
 190 #endif
 191         } else {
 192                 return NULL;
 193         }
 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                 goto exit;
 234         }
 235
 236         sk = NULL;
 237 exit:
 238
 239         return sk;
 240 }
 241
 242 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 243                                           kgid_t *high)
 244 {
 245         kgid_t *data = net->ipv4.ping_group_range.range;
 246         unsigned int seq;
 247
 248         do {
 249                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 250
 251                 *low = data[0];
 252                 *high = data[1];
 253         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 254 }
 255
 256
 257 int ping_init_sock(struct sock *sk)
 258 {
 259         struct net *net = sock_net(sk);
 260         kgid_t group = current_egid();
 261         struct group_info *group_info;
 262         int i;
 263         kgid_t low, high;
 264         int ret = 0;
 265
 266         if (sk->sk_family == AF_INET6)
 267                 sk->sk_ipv6only = 1;
 268
 269         inet_get_ping_group_range_net(net, &low, &high);
 270         if (gid_lte(low, group) && gid_lte(group, high))
 271                 return 0;
 272
 273         group_info = get_current_groups();
 274         for (i = 0; i < group_info->ngroups; i++) {
 275                 kgid_t gid = group_info->gid[i];
 276
 277                 if (gid_lte(low, gid) && gid_lte(gid, high))
 278                         goto out_release_group;
 279         }
 280
 281         ret = -EACCES;
 282
 283 out_release_group:
 284         put_group_info(group_info);
 285         return ret;
 286 }
 287 EXPORT_SYMBOL_GPL(ping_init_sock);
 288
 289 void ping_close(struct sock *sk, long timeout)
 290 {
 291         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 292                  inet_sk(sk), inet_sk(sk)->inet_num);
 293         pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
 294
 295         sk_common_release(sk);
 296 }
 297 EXPORT_SYMBOL_GPL(ping_close);
 298
 299 static int ping_pre_connect(struct sock *sk, struct sockaddr *uaddr,
 300                             int addr_len)
 301 {
 302         /* This check is replicated from __ip4_datagram_connect() and
 303          * intended to prevent BPF program called below from accessing bytes
 304          * that are out of the bound specified by user in addr_len.
 305          */
 306         if (addr_len < sizeof(struct sockaddr_in))
 307                 return -EINVAL;
 308
 309         return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr);
 310 }
 311
 312 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 313 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 314                                 struct sockaddr *uaddr, int addr_len)
 315 {
 316         struct net *net = sock_net(sk);
 317         if (sk->sk_family == AF_INET) {
 318                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 319                 u32 tb_id = RT_TABLE_LOCAL;
 320                 int chk_addr_ret;
 321
 322                 if (addr_len < sizeof(*addr))
 323                         return -EINVAL;
 324
 325                 if (addr->sin_family != AF_INET &&
 326                     !(addr->sin_family == AF_UNSPEC &&
 327                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 328                         return -EAFNOSUPPORT;
 329
 330                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 331                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 332
 333                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 334                         return 0;
 335
 336                 tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ? : tb_id;
 337                 chk_addr_ret = inet_addr_type_table(net, addr->sin_addr.s_addr, tb_id);
 338
 339                 if (chk_addr_ret == RTN_MULTICAST ||
 340                     chk_addr_ret == RTN_BROADCAST ||
 341                     (chk_addr_ret != RTN_LOCAL &&
 342                      !inet_can_nonlocal_bind(net, isk)))
 343                         return -EADDRNOTAVAIL;
 344
 345 #if IS_ENABLED(CONFIG_IPV6)
 346         } else if (sk->sk_family == AF_INET6) {
 347                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 348                 int addr_type, scoped, has_addr;
 349                 struct net_device *dev = NULL;
 350
 351                 if (addr_len < sizeof(*addr))
 352                         return -EINVAL;
 353
 354                 if (addr->sin6_family != AF_INET6)
 355                         return -EAFNOSUPPORT;
 356
 357                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 358                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 359
 360                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 361                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 362                 if ((addr_type != IPV6_ADDR_ANY &&
 363                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 364                     (scoped && !addr->sin6_scope_id))
 365                         return -EINVAL;
 366
 367                 rcu_read_lock();
 368                 if (addr->sin6_scope_id) {
 369                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 370                         if (!dev) {
 371                                 rcu_read_unlock();
 372                                 return -ENODEV;
 373                         }
 374                 }
 375
 376                 if (!dev && sk->sk_bound_dev_if) {
 377                         dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
 378                         if (!dev) {
 379                                 rcu_read_unlock();
 380                                 return -ENODEV;
 381                         }
 382                 }
 383                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 384                                                     scoped);
 385                 rcu_read_unlock();
 386
 387                 if (!(ipv6_can_nonlocal_bind(net, isk) || has_addr ||
 388                       addr_type == IPV6_ADDR_ANY))
 389                         return -EADDRNOTAVAIL;
 390
 391                 if (scoped)
 392                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 393 #endif
 394         } else {
 395                 return -EAFNOSUPPORT;
 396         }
 397         return 0;
 398 }
 399
 400 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 401 {
 402         if (saddr->sa_family == AF_INET) {
 403                 struct inet_sock *isk = inet_sk(sk);
 404                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 405                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 406 #if IS_ENABLED(CONFIG_IPV6)
 407         } else if (saddr->sa_family == AF_INET6) {
 408                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 409                 struct ipv6_pinfo *np = inet6_sk(sk);
 410                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 411 #endif
 412         }
 413 }
 414
 415 /*
 416  * We need our own bind because there are no privileged id's == local ports.
 417  * Moreover, we don't allow binding to multi- and broadcast addresses.
 418  */
 419
 420 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 421 {
 422         struct inet_sock *isk = inet_sk(sk);
 423         unsigned short snum;
 424         int err;
 425         int dif = sk->sk_bound_dev_if;
 426
 427         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 428         if (err)
 429                 return err;
 430
 431         lock_sock(sk);
 432
 433         err = -EINVAL;
 434         if (isk->inet_num != 0)
 435                 goto out;
 436
 437         err = -EADDRINUSE;
 438         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 439         if (ping_get_port(sk, snum) != 0) {
 440                 /* Restore possibly modified sk->sk_bound_dev_if by ping_check_bind_addr(). */
 441                 sk->sk_bound_dev_if = dif;
 442                 goto out;
 443         }
 444         ping_set_saddr(sk, uaddr);
 445
 446         pr_debug("after bind(): num = %hu, dif = %d\n",
 447                  isk->inet_num,
 448                  sk->sk_bound_dev_if);
 449
 450         err = 0;
 451         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 452                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 453 #if IS_ENABLED(CONFIG_IPV6)
 454         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 455                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 456 #endif
 457
 458         if (snum)
 459                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 460         isk->inet_sport = htons(isk->inet_num);
 461         isk->inet_daddr = 0;
 462         isk->inet_dport = 0;
 463
 464 #if IS_ENABLED(CONFIG_IPV6)
 465         if (sk->sk_family == AF_INET6)
 466                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 467 #endif
 468
 469         sk_dst_reset(sk);
 470 out:
 471         release_sock(sk);
 472         pr_debug("ping_v4_bind -> %d\n", err);
 473         return err;
 474 }
 475 EXPORT_SYMBOL_GPL(ping_bind);
 476
 477 /*
 478  * Is this a supported type of ICMP message?
 479  */
 480
 481 static inline int ping_supported(int family, int type, int code)
 482 {
 483         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 484                (family == AF_INET && type == ICMP_EXT_ECHO && code == 0) ||
 485                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0) ||
 486                (family == AF_INET6 && type == ICMPV6_EXT_ECHO_REQUEST && code == 0);
 487 }
 488
 489 /*
 490  * This routine is called by the ICMP module when it gets some
 491  * sort of error condition.
 492  */
 493
 494 void ping_err(struct sk_buff *skb, int offset, u32 info)
 495 {
 496         int family;
 497         struct icmphdr *icmph;
 498         struct inet_sock *inet_sock;
 499         int type;
 500         int code;
 501         struct net *net = dev_net(skb->dev);
 502         struct sock *sk;
 503         int harderr;
 504         int err;
 505
 506         if (skb->protocol == htons(ETH_P_IP)) {
 507                 family = AF_INET;
 508                 type = icmp_hdr(skb)->type;
 509                 code = icmp_hdr(skb)->code;
 510                 icmph = (struct icmphdr *)(skb->data + offset);
 511         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 512                 family = AF_INET6;
 513                 type = icmp6_hdr(skb)->icmp6_type;
 514                 code = icmp6_hdr(skb)->icmp6_code;
 515                 icmph = (struct icmphdr *) (skb->data + offset);
 516         } else {
 517                 BUG();
 518         }
 519
 520         /* We assume the packet has already been checked by icmp_unreach */
 521
 522         if (!ping_supported(family, icmph->type, icmph->code))
 523                 return;
 524
 525         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 526                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 527                  ntohs(icmph->un.echo.sequence));
 528
 529         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 530         if (!sk) {
 531                 pr_debug("no socket, dropping\n");
 532                 return; /* No socket for error */
 533         }
 534         pr_debug("err on socket %p\n", sk);
 535
 536         err = 0;
 537         harderr = 0;
 538         inet_sock = inet_sk(sk);
 539
 540         if (skb->protocol == htons(ETH_P_IP)) {
 541                 switch (type) {
 542                 default:
 543                 case ICMP_TIME_EXCEEDED:
 544                         err = EHOSTUNREACH;
 545                         break;
 546                 case ICMP_SOURCE_QUENCH:
 547                         /* This is not a real error but ping wants to see it.
 548                          * Report it with some fake errno.
 549                          */
 550                         err = EREMOTEIO;
 551                         break;
 552                 case ICMP_PARAMETERPROB:
 553                         err = EPROTO;
 554                         harderr = 1;
 555                         break;
 556                 case ICMP_DEST_UNREACH:
 557                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 558                                 ipv4_sk_update_pmtu(skb, sk, info);
 559                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 560                                         err = EMSGSIZE;
 561                                         harderr = 1;
 562                                         break;
 563                                 }
 564                                 goto out;
 565                         }
 566                         err = EHOSTUNREACH;
 567                         if (code <= NR_ICMP_UNREACH) {
 568                                 harderr = icmp_err_convert[code].fatal;
 569                                 err = icmp_err_convert[code].errno;
 570                         }
 571                         break;
 572                 case ICMP_REDIRECT:
 573                         /* See ICMP_SOURCE_QUENCH */
 574                         ipv4_sk_redirect(skb, sk);
 575                         err = EREMOTEIO;
 576                         break;
 577                 }
 578 #if IS_ENABLED(CONFIG_IPV6)
 579         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 580                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 581 #endif
 582         }
 583
 584         /*
 585          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 586          *      4.1.3.3.
 587          */
 588         if ((family == AF_INET && !inet_sock->recverr) ||
 589             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 590                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 591                         goto out;
 592         } else {
 593                 if (family == AF_INET) {
 594                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 595                                       info, (u8 *)icmph);
 596 #if IS_ENABLED(CONFIG_IPV6)
 597                 } else if (family == AF_INET6) {
 598                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 599                                                    info, (u8 *)icmph);
 600 #endif
 601                 }
 602         }
 603         sk->sk_err = err;
 604         sk_error_report(sk);
 605 out:
 606         return;
 607 }
 608 EXPORT_SYMBOL_GPL(ping_err);
 609
 610 /*
 611  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 612  *      starting from the payload.
 613  */
 614
 615 int ping_getfrag(void *from, char *to,
 616                  int offset, int fraglen, int odd, struct sk_buff *skb)
 617 {
 618         struct pingfakehdr *pfh = from;
 619
 620         if (offset == 0) {
 621                 fraglen -= sizeof(struct icmphdr);
 622                 if (fraglen < 0)
 623                         BUG();
 624                 if (!csum_and_copy_from_iter_full(to + sizeof(struct icmphdr),
 625                             fraglen, &pfh->wcheck,
 626                             &pfh->msg->msg_iter))
 627                         return -EFAULT;
 628         } else if (offset < sizeof(struct icmphdr)) {
 629                         BUG();
 630         } else {
 631                 if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
 632                                             &pfh->msg->msg_iter))
 633                         return -EFAULT;
 634         }
 635
 636 #if IS_ENABLED(CONFIG_IPV6)
 637         /* For IPv6, checksum each skb as we go along, as expected by
 638          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 639          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 640          */
 641         if (pfh->family == AF_INET6) {
 642                 skb->csum = pfh->wcheck;
 643                 skb->ip_summed = CHECKSUM_NONE;
 644                 pfh->wcheck = 0;
 645         }
 646 #endif
 647
 648         return 0;
 649 }
 650 EXPORT_SYMBOL_GPL(ping_getfrag);
 651
 652 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 653                                        struct flowi4 *fl4)
 654 {
 655         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 656
 657         if (!skb)
 658                 return 0;
 659         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 660                 sizeof(struct icmphdr), pfh->wcheck);
 661         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 662         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 663         skb->ip_summed = CHECKSUM_NONE;
 664         return ip_push_pending_frames(sk, fl4);
 665 }
 666
 667 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 668                         void *user_icmph, size_t icmph_len)
 669 {
 670         u8 type, code;
 671
 672         if (len > 0xFFFF)
 673                 return -EMSGSIZE;
 674
 675         /* Must have at least a full ICMP header. */
 676         if (len < icmph_len)
 677                 return -EINVAL;
 678
 679         /*
 680          *      Check the flags.
 681          */
 682
 683         /* Mirror BSD error message compatibility */
 684         if (msg->msg_flags & MSG_OOB)
 685                 return -EOPNOTSUPP;
 686
 687         /*
 688          *      Fetch the ICMP header provided by the userland.
 689          *      iovec is modified! The ICMP header is consumed.
 690          */
 691         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 692                 return -EFAULT;
 693
 694         if (family == AF_INET) {
 695                 type = ((struct icmphdr *) user_icmph)->type;
 696                 code = ((struct icmphdr *) user_icmph)->code;
 697 #if IS_ENABLED(CONFIG_IPV6)
 698         } else if (family == AF_INET6) {
 699                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 700                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 701 #endif
 702         } else {
 703                 BUG();
 704         }
 705
 706         if (!ping_supported(family, type, code))
 707                 return -EINVAL;
 708
 709         return 0;
 710 }
 711 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 712
 713 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 714 {
 715         struct net *net = sock_net(sk);
 716         struct flowi4 fl4;
 717         struct inet_sock *inet = inet_sk(sk);
 718         struct ipcm_cookie ipc;
 719         struct icmphdr user_icmph;
 720         struct pingfakehdr pfh;
 721         struct rtable *rt = NULL;
 722         struct ip_options_data opt_copy;
 723         int free = 0;
 724         __be32 saddr, daddr, faddr;
 725         u8  tos;
 726         int err;
 727
 728         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 729
 730         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 731                                   sizeof(user_icmph));
 732         if (err)
 733                 return err;
 734
 735         /*
 736          *      Get and verify the address.
 737          */
 738
 739         if (msg->msg_name) {
 740                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 741                 if (msg->msg_namelen < sizeof(*usin))
 742                         return -EINVAL;
 743                 if (usin->sin_family != AF_INET)
 744                         return -EAFNOSUPPORT;
 745                 daddr = usin->sin_addr.s_addr;
 746                 /* no remote port */
 747         } else {
 748                 if (sk->sk_state != TCP_ESTABLISHED)
 749                         return -EDESTADDRREQ;
 750                 daddr = inet->inet_daddr;
 751                 /* no remote port */
 752         }
 753
 754         ipcm_init_sk(&ipc, inet);
 755
 756         if (msg->msg_controllen) {
 757                 err = ip_cmsg_send(sk, msg, &ipc, false);
 758                 if (unlikely(err)) {
 759                         kfree(ipc.opt);
 760                         return err;
 761                 }
 762                 if (ipc.opt)
 763                         free = 1;
 764         }
 765         if (!ipc.opt) {
 766                 struct ip_options_rcu *inet_opt;
 767
 768                 rcu_read_lock();
 769                 inet_opt = rcu_dereference(inet->inet_opt);
 770                 if (inet_opt) {
 771                         memcpy(&opt_copy, inet_opt,
 772                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 773                         ipc.opt = &opt_copy.opt;
 774                 }
 775                 rcu_read_unlock();
 776         }
 777
 778         saddr = ipc.addr;
 779         ipc.addr = faddr = daddr;
 780
 781         if (ipc.opt && ipc.opt->opt.srr) {
 782                 if (!daddr) {
 783                         err = -EINVAL;
 784                         goto out_free;
 785                 }
 786                 faddr = ipc.opt->opt.faddr;
 787         }
 788         tos = get_rttos(&ipc, inet);
 789         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 790             (msg->msg_flags & MSG_DONTROUTE) ||
 791             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 792                 tos |= RTO_ONLINK;
 793         }
 794
 795         if (ipv4_is_multicast(daddr)) {
 796                 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
 797                         ipc.oif = inet->mc_index;
 798                 if (!saddr)
 799                         saddr = inet->mc_addr;
 800         } else if (!ipc.oif)
 801                 ipc.oif = inet->uc_index;
 802
 803         flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos,
 804                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 805                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
 806                            sk->sk_uid);
 807
 808         fl4.fl4_icmp_type = user_icmph.type;
 809         fl4.fl4_icmp_code = user_icmph.code;
 810
 811         security_sk_classify_flow(sk, flowi4_to_flowi_common(&fl4));
 812         rt = ip_route_output_flow(net, &fl4, sk);
 813         if (IS_ERR(rt)) {
 814                 err = PTR_ERR(rt);
 815                 rt = NULL;
 816                 if (err == -ENETUNREACH)
 817                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 818                 goto out;
 819         }
 820
 821         err = -EACCES;
 822         if ((rt->rt_flags & RTCF_BROADCAST) &&
 823             !sock_flag(sk, SOCK_BROADCAST))
 824                 goto out;
 825
 826         if (msg->msg_flags & MSG_CONFIRM)
 827                 goto do_confirm;
 828 back_from_confirm:
 829
 830         if (!ipc.addr)
 831                 ipc.addr = fl4.daddr;
 832
 833         lock_sock(sk);
 834
 835         pfh.icmph.type = user_icmph.type; /* already checked */
 836         pfh.icmph.code = user_icmph.code; /* ditto */
 837         pfh.icmph.checksum = 0;
 838         pfh.icmph.un.echo.id = inet->inet_sport;
 839         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 840         pfh.msg = msg;
 841         pfh.wcheck = 0;
 842         pfh.family = AF_INET;
 843
 844         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 845                         0, &ipc, &rt, msg->msg_flags);
 846         if (err)
 847                 ip_flush_pending_frames(sk);
 848         else
 849                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 850         release_sock(sk);
 851
 852 out:
 853         ip_rt_put(rt);
 854 out_free:
 855         if (free)
 856                 kfree(ipc.opt);
 857         if (!err) {
 858                 icmp_out_count(sock_net(sk), user_icmph.type);
 859                 return len;
 860         }
 861         return err;
 862
 863 do_confirm:
 864         if (msg->msg_flags & MSG_PROBE)
 865                 dst_confirm_neigh(&rt->dst, &fl4.daddr);
 866         if (!(msg->msg_flags & MSG_PROBE) || len)
 867                 goto back_from_confirm;
 868         err = 0;
 869         goto out;
 870 }
 871
 872 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
 873                  int *addr_len)
 874 {
 875         struct inet_sock *isk = inet_sk(sk);
 876         int family = sk->sk_family;
 877         struct sk_buff *skb;
 878         int copied, err;
 879
 880         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 881
 882         err = -EOPNOTSUPP;
 883         if (flags & MSG_OOB)
 884                 goto out;
 885
 886         if (flags & MSG_ERRQUEUE)
 887                 return inet_recv_error(sk, msg, len, addr_len);
 888
 889         skb = skb_recv_datagram(sk, flags, &err);
 890         if (!skb)
 891                 goto out;
 892
 893         copied = skb->len;
 894         if (copied > len) {
 895                 msg->msg_flags |= MSG_TRUNC;
 896                 copied = len;
 897         }
 898
 899         /* Don't bother checking the checksum */
 900         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 901         if (err)
 902                 goto done;
 903
 904         sock_recv_timestamp(msg, sk, skb);
 905
 906         /* Copy the address and add cmsg data. */
 907         if (family == AF_INET) {
 908                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 909
 910                 if (sin) {
 911                         sin->sin_family = AF_INET;
 912                         sin->sin_port = 0 /* skb->h.uh->source */;
 913                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 914                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 915                         *addr_len = sizeof(*sin);
 916                 }
 917
 918                 if (isk->cmsg_flags)
 919                         ip_cmsg_recv(msg, skb);
 920
 921 #if IS_ENABLED(CONFIG_IPV6)
 922         } else if (family == AF_INET6) {
 923                 struct ipv6_pinfo *np = inet6_sk(sk);
 924                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 925                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 926
 927                 if (sin6) {
 928                         sin6->sin6_family = AF_INET6;
 929                         sin6->sin6_port = 0;
 930                         sin6->sin6_addr = ip6->saddr;
 931                         sin6->sin6_flowinfo = 0;
 932                         if (np->sndflow)
 933                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 934                         sin6->sin6_scope_id =
 935                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 936                                                     inet6_iif(skb));
 937                         *addr_len = sizeof(*sin6);
 938                 }
 939
 940                 if (inet6_sk(sk)->rxopt.all)
 941                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 942                 if (skb->protocol == htons(ETH_P_IPV6) &&
 943                     inet6_sk(sk)->rxopt.all)
 944                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 945                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 946                         ip_cmsg_recv(msg, skb);
 947 #endif
 948         } else {
 949                 BUG();
 950         }
 951
 952         err = copied;
 953
 954 done:
 955         skb_free_datagram(sk, skb);
 956 out:
 957         pr_debug("ping_recvmsg -> %d\n", err);
 958         return err;
 959 }
 960 EXPORT_SYMBOL_GPL(ping_recvmsg);
 961
 962 static enum skb_drop_reason __ping_queue_rcv_skb(struct sock *sk,
 963                                                  struct sk_buff *skb)
 964 {
 965         enum skb_drop_reason reason;
 966
 967         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 968                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 969         if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
 970                 kfree_skb_reason(skb, reason);
 971                 pr_debug("ping_queue_rcv_skb -> failed\n");
 972                 return reason;
 973         }
 974         return SKB_NOT_DROPPED_YET;
 975 }
 976
 977 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 978 {
 979         return __ping_queue_rcv_skb(sk, skb) ? -1 : 0;
 980 }
 981 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 982
 983
 984 /*
 985  *      All we need to do is get the socket.
 986  */
 987
 988 enum skb_drop_reason ping_rcv(struct sk_buff *skb)
 989 {
 990         enum skb_drop_reason reason = SKB_DROP_REASON_NO_SOCKET;
 991         struct sock *sk;
 992         struct net *net = dev_net(skb->dev);
 993         struct icmphdr *icmph = icmp_hdr(skb);
 994
 995         /* We assume the packet has already been checked by icmp_rcv */
 996
 997         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 998                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 999
1000         /* Push ICMP header back */
1001         skb_push(skb, skb->data - (u8 *)icmph);
1002
1003         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
1004         if (sk) {
1005                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
1006
1007                 pr_debug("rcv on socket %p\n", sk);
1008                 if (skb2)
1009                         reason = __ping_queue_rcv_skb(sk, skb2);
1010                 else
1011                         reason = SKB_DROP_REASON_NOMEM;
1012         }
1013
1014         if (reason)
1015                 pr_debug("no socket, dropping\n");
1016
1017         return reason;
1018 }
1019 EXPORT_SYMBOL_GPL(ping_rcv);
1020
1021 struct proto ping_prot = {
1022         .name =         "PING",
1023         .owner =        THIS_MODULE,
1024         .init =         ping_init_sock,
1025         .close =        ping_close,
1026         .pre_connect =  ping_pre_connect,
1027         .connect =      ip4_datagram_connect,
1028         .disconnect =   __udp_disconnect,
1029         .setsockopt =   ip_setsockopt,
1030         .getsockopt =   ip_getsockopt,
1031         .sendmsg =      ping_v4_sendmsg,
1032         .recvmsg =      ping_recvmsg,
1033         .bind =         ping_bind,
1034         .backlog_rcv =  ping_queue_rcv_skb,
1035         .release_cb =   ip4_datagram_release_cb,
1036         .hash =         ping_hash,
1037         .unhash =       ping_unhash,
1038         .get_port =     ping_get_port,
1039         .put_port =     ping_unhash,
1040         .obj_size =     sizeof(struct inet_sock),
1041 };
1042 EXPORT_SYMBOL(ping_prot);
1043
1044 #ifdef CONFIG_PROC_FS
1045
1046 static struct sock *ping_get_first(struct seq_file *seq, int start)
1047 {
1048         struct sock *sk;
1049         struct ping_iter_state *state = seq->private;
1050         struct net *net = seq_file_net(seq);
1051
1052         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1053              ++state->bucket) {
1054                 struct hlist_nulls_node *node;
1055                 struct hlist_nulls_head *hslot;
1056
1057                 hslot = &ping_table.hash[state->bucket];
1058
1059                 if (hlist_nulls_empty(hslot))
1060                         continue;
1061
1062                 sk_nulls_for_each(sk, node, hslot) {
1063                         if (net_eq(sock_net(sk), net) &&
1064                             sk->sk_family == state->family)
1065                                 goto found;
1066                 }
1067         }
1068         sk = NULL;
1069 found:
1070         return sk;
1071 }
1072
1073 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1074 {
1075         struct ping_iter_state *state = seq->private;
1076         struct net *net = seq_file_net(seq);
1077
1078         do {
1079                 sk = sk_nulls_next(sk);
1080         } while (sk && (!net_eq(sock_net(sk), net)));
1081
1082         if (!sk)
1083                 return ping_get_first(seq, state->bucket + 1);
1084         return sk;
1085 }
1086
1087 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1088 {
1089         struct sock *sk = ping_get_first(seq, 0);
1090
1091         if (sk)
1092                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1093                         --pos;
1094         return pos ? NULL : sk;
1095 }
1096
1097 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1098         __acquires(RCU)
1099 {
1100         struct ping_iter_state *state = seq->private;
1101         state->bucket = 0;
1102         state->family = family;
1103
1104         rcu_read_lock();
1105
1106         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1107 }
1108 EXPORT_SYMBOL_GPL(ping_seq_start);
1109
1110 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1111 {
1112         return ping_seq_start(seq, pos, AF_INET);
1113 }
1114
1115 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1116 {
1117         struct sock *sk;
1118
1119         if (v == SEQ_START_TOKEN)
1120                 sk = ping_get_idx(seq, 0);
1121         else
1122                 sk = ping_get_next(seq, v);
1123
1124         ++*pos;
1125         return sk;
1126 }
1127 EXPORT_SYMBOL_GPL(ping_seq_next);
1128
1129 void ping_seq_stop(struct seq_file *seq, void *v)
1130         __releases(RCU)
1131 {
1132         rcu_read_unlock();
1133 }
1134 EXPORT_SYMBOL_GPL(ping_seq_stop);
1135
1136 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1137                 int bucket)
1138 {
1139         struct inet_sock *inet = inet_sk(sp);
1140         __be32 dest = inet->inet_daddr;
1141         __be32 src = inet->inet_rcv_saddr;
1142         __u16 destp = ntohs(inet->inet_dport);
1143         __u16 srcp = ntohs(inet->inet_sport);
1144
1145         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1146                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
1147                 bucket, src, srcp, dest, destp, sp->sk_state,
1148                 sk_wmem_alloc_get(sp),
1149                 sk_rmem_alloc_get(sp),
1150                 0, 0L, 0,
1151                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1152                 0, sock_i_ino(sp),
1153                 refcount_read(&sp->sk_refcnt), sp,
1154                 atomic_read(&sp->sk_drops));
1155 }
1156
1157 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1158 {
1159         seq_setwidth(seq, 127);
1160         if (v == SEQ_START_TOKEN)
1161                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1162                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1163                            "inode ref pointer drops");
1164         else {
1165                 struct ping_iter_state *state = seq->private;
1166
1167                 ping_v4_format_sock(v, seq, state->bucket);
1168         }
1169         seq_pad(seq, '\n');
1170         return 0;
1171 }
1172
1173 static const struct seq_operations ping_v4_seq_ops = {
1174         .start          = ping_v4_seq_start,
1175         .show           = ping_v4_seq_show,
1176         .next           = ping_seq_next,
1177         .stop           = ping_seq_stop,
1178 };
1179
1180 static int __net_init ping_v4_proc_init_net(struct net *net)
1181 {
1182         if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
1183                         sizeof(struct ping_iter_state)))
1184                 return -ENOMEM;
1185         return 0;
1186 }
1187
1188 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1189 {
1190         remove_proc_entry("icmp", net->proc_net);
1191 }
1192
1193 static struct pernet_operations ping_v4_net_ops = {
1194         .init = ping_v4_proc_init_net,
1195         .exit = ping_v4_proc_exit_net,
1196 };
1197
1198 int __init ping_proc_init(void)
1199 {
1200         return register_pernet_subsys(&ping_v4_net_ops);
1201 }
1202
1203 void ping_proc_exit(void)
1204 {
1205         unregister_pernet_subsys(&ping_v4_net_ops);
1206 }
1207
1208 #endif
1209
1210 void __init ping_init(void)
1211 {
1212         int i;
1213
1214         for (i = 0; i < PING_HTABLE_SIZE; i++)
1215                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1216         spin_lock_init(&ping_table.lock);
1217 }