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 #define ping_portaddr_for_each_entry(__sk, node, list) \
  53         hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
  54 #define ping_portaddr_for_each_entry_rcu(__sk, node, list) \
  55         hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
  56
  57 struct ping_table {
  58         struct hlist_nulls_head hash[PING_HTABLE_SIZE];
  59         spinlock_t              lock;
  60 };
  61
  62 static struct ping_table ping_table;
  63 struct pingv6_ops pingv6_ops;
  64 EXPORT_SYMBOL_GPL(pingv6_ops);
  65
  66 static u16 ping_port_rover;
  67
  68 static inline u32 ping_hashfn(const struct net *net, u32 num, u32 mask)
  69 {
  70         u32 res = (num + net_hash_mix(net)) & mask;
  71
  72         pr_debug("hash(%u) = %u\n", num, res);
  73         return res;
  74 }
  75 EXPORT_SYMBOL_GPL(ping_hash);
  76
  77 static inline struct hlist_nulls_head *ping_hashslot(struct ping_table *table,
  78                                              struct net *net, unsigned int num)
  79 {
  80         return &table->hash[ping_hashfn(net, num, PING_HTABLE_MASK)];
  81 }
  82
  83 int ping_get_port(struct sock *sk, unsigned short ident)
  84 {
  85         struct hlist_nulls_node *node;
  86         struct hlist_nulls_head *hlist;
  87         struct inet_sock *isk, *isk2;
  88         struct sock *sk2 = NULL;
  89
  90         isk = inet_sk(sk);
  91         spin_lock(&ping_table.lock);
  92         if (ident == 0) {
  93                 u32 i;
  94                 u16 result = ping_port_rover + 1;
  95
  96                 for (i = 0; i < (1L << 16); i++, result++) {
  97                         if (!result)
  98                                 result++; /* avoid zero */
  99                         hlist = ping_hashslot(&ping_table, sock_net(sk),
 100                                             result);
 101                         ping_portaddr_for_each_entry(sk2, node, hlist) {
 102                                 isk2 = inet_sk(sk2);
 103
 104                                 if (isk2->inet_num == result)
 105                                         goto next_port;
 106                         }
 107
 108                         /* found */
 109                         ping_port_rover = ident = result;
 110                         break;
 111 next_port:
 112                         ;
 113                 }
 114                 if (i >= (1L << 16))
 115                         goto fail;
 116         } else {
 117                 hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
 118                 ping_portaddr_for_each_entry(sk2, node, hlist) {
 119                         isk2 = inet_sk(sk2);
 120
 121                         /* BUG? Why is this reuse and not reuseaddr? ping.c
 122                          * doesn't turn off SO_REUSEADDR, and it doesn't expect
 123                          * that other ping processes can steal its packets.
 124                          */
 125                         if ((isk2->inet_num == ident) &&
 126                             (sk2 != sk) &&
 127                             (!sk2->sk_reuse || !sk->sk_reuse))
 128                                 goto fail;
 129                 }
 130         }
 131
 132         pr_debug("found port/ident = %d\n", ident);
 133         isk->inet_num = ident;
 134         if (sk_unhashed(sk)) {
 135                 pr_debug("was not hashed\n");
 136                 sock_hold(sk);
 137                 sock_set_flag(sk, SOCK_RCU_FREE);
 138                 hlist_nulls_add_head_rcu(&sk->sk_nulls_node, hlist);
 139                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 140         }
 141         spin_unlock(&ping_table.lock);
 142         return 0;
 143
 144 fail:
 145         spin_unlock(&ping_table.lock);
 146         return -EADDRINUSE;
 147 }
 148 EXPORT_SYMBOL_GPL(ping_get_port);
 149
 150 int ping_hash(struct sock *sk)
 151 {
 152         pr_debug("ping_hash(sk->port=%u)\n", inet_sk(sk)->inet_num);
 153         BUG(); /* "Please do not press this button again." */
 154
 155         return 0;
 156 }
 157
 158 void ping_unhash(struct sock *sk)
 159 {
 160         struct inet_sock *isk = inet_sk(sk);
 161
 162         pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
 163         spin_lock(&ping_table.lock);
 164         if (sk_hashed(sk)) {
 165                 hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
 166                 sock_put(sk);
 167                 isk->inet_num = 0;
 168                 isk->inet_sport = 0;
 169                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 170         }
 171         spin_unlock(&ping_table.lock);
 172 }
 173 EXPORT_SYMBOL_GPL(ping_unhash);
 174
 175 /* Called under rcu_read_lock() */
 176 static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 177 {
 178         struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
 179         struct sock *sk = NULL;
 180         struct inet_sock *isk;
 181         struct hlist_nulls_node *hnode;
 182         int dif, sdif;
 183
 184         if (skb->protocol == htons(ETH_P_IP)) {
 185                 dif = inet_iif(skb);
 186                 sdif = inet_sdif(skb);
 187                 pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
 188                          (int)ident, &ip_hdr(skb)->daddr, dif);
 189 #if IS_ENABLED(CONFIG_IPV6)
 190         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 191                 dif = inet6_iif(skb);
 192                 sdif = inet6_sdif(skb);
 193                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 194                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
 195 #endif
 196         } else {
 197                 return NULL;
 198         }
 199
 200         ping_portaddr_for_each_entry_rcu(sk, hnode, hslot) {
 201                 isk = inet_sk(sk);
 202
 203                 pr_debug("iterate\n");
 204                 if (isk->inet_num != ident)
 205                         continue;
 206
 207                 if (skb->protocol == htons(ETH_P_IP) &&
 208                     sk->sk_family == AF_INET) {
 209                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 210                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
 211                                  sk->sk_bound_dev_if);
 212
 213                         if (isk->inet_rcv_saddr &&
 214                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 215                                 continue;
 216 #if IS_ENABLED(CONFIG_IPV6)
 217                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
 218                            sk->sk_family == AF_INET6) {
 219
 220                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 221                                  (int) isk->inet_num,
 222                                  &sk->sk_v6_rcv_saddr,
 223                                  sk->sk_bound_dev_if);
 224
 225                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 226                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 227                                              &ipv6_hdr(skb)->daddr))
 228                                 continue;
 229 #endif
 230                 } else {
 231                         continue;
 232                 }
 233
 234                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif &&
 235                     sk->sk_bound_dev_if != sdif)
 236                         continue;
 237
 238                 goto exit;
 239         }
 240
 241         sk = NULL;
 242 exit:
 243
 244         return sk;
 245 }
 246
 247 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 248                                           kgid_t *high)
 249 {
 250         kgid_t *data = net->ipv4.ping_group_range.range;
 251         unsigned int seq;
 252
 253         do {
 254                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 255
 256                 *low = data[0];
 257                 *high = data[1];
 258         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 259 }
 260
 261
 262 int ping_init_sock(struct sock *sk)
 263 {
 264         struct net *net = sock_net(sk);
 265         kgid_t group = current_egid();
 266         struct group_info *group_info;
 267         int i;
 268         kgid_t low, high;
 269         int ret = 0;
 270
 271         if (sk->sk_family == AF_INET6)
 272                 sk->sk_ipv6only = 1;
 273
 274         inet_get_ping_group_range_net(net, &low, &high);
 275         if (gid_lte(low, group) && gid_lte(group, high))
 276                 return 0;
 277
 278         group_info = get_current_groups();
 279         for (i = 0; i < group_info->ngroups; i++) {
 280                 kgid_t gid = group_info->gid[i];
 281
 282                 if (gid_lte(low, gid) && gid_lte(gid, high))
 283                         goto out_release_group;
 284         }
 285
 286         ret = -EACCES;
 287
 288 out_release_group:
 289         put_group_info(group_info);
 290         return ret;
 291 }
 292 EXPORT_SYMBOL_GPL(ping_init_sock);
 293
 294 void ping_close(struct sock *sk, long timeout)
 295 {
 296         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 297                  inet_sk(sk), inet_sk(sk)->inet_num);
 298         pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
 299
 300         sk_common_release(sk);
 301 }
 302 EXPORT_SYMBOL_GPL(ping_close);
 303
 304 static int ping_pre_connect(struct sock *sk, struct sockaddr *uaddr,
 305                             int addr_len)
 306 {
 307         /* This check is replicated from __ip4_datagram_connect() and
 308          * intended to prevent BPF program called below from accessing bytes
 309          * that are out of the bound specified by user in addr_len.
 310          */
 311         if (addr_len < sizeof(struct sockaddr_in))
 312                 return -EINVAL;
 313
 314         return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr);
 315 }
 316
 317 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 318 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 319                                 struct sockaddr *uaddr, int addr_len)
 320 {
 321         struct net *net = sock_net(sk);
 322         if (sk->sk_family == AF_INET) {
 323                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 324                 u32 tb_id = RT_TABLE_LOCAL;
 325                 int chk_addr_ret;
 326
 327                 if (addr_len < sizeof(*addr))
 328                         return -EINVAL;
 329
 330                 if (addr->sin_family != AF_INET &&
 331                     !(addr->sin_family == AF_UNSPEC &&
 332                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 333                         return -EAFNOSUPPORT;
 334
 335                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 336                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 337
 338                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 339                         return 0;
 340
 341                 tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ? : tb_id;
 342                 chk_addr_ret = inet_addr_type_table(net, addr->sin_addr.s_addr, tb_id);
 343
 344                 if (chk_addr_ret == RTN_MULTICAST ||
 345                     chk_addr_ret == RTN_BROADCAST ||
 346                     (chk_addr_ret != RTN_LOCAL &&
 347                      !inet_can_nonlocal_bind(net, isk)))
 348                         return -EADDRNOTAVAIL;
 349
 350 #if IS_ENABLED(CONFIG_IPV6)
 351         } else if (sk->sk_family == AF_INET6) {
 352                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 353                 int addr_type, scoped, has_addr;
 354                 struct net_device *dev = NULL;
 355
 356                 if (addr_len < sizeof(*addr))
 357                         return -EINVAL;
 358
 359                 if (addr->sin6_family != AF_INET6)
 360                         return -EAFNOSUPPORT;
 361
 362                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 363                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 364
 365                 addr_type = ipv6_addr_type(&addr->sin6_addr);
 366                 scoped = __ipv6_addr_needs_scope_id(addr_type);
 367                 if ((addr_type != IPV6_ADDR_ANY &&
 368                      !(addr_type & IPV6_ADDR_UNICAST)) ||
 369                     (scoped && !addr->sin6_scope_id))
 370                         return -EINVAL;
 371
 372                 rcu_read_lock();
 373                 if (addr->sin6_scope_id) {
 374                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 375                         if (!dev) {
 376                                 rcu_read_unlock();
 377                                 return -ENODEV;
 378                         }
 379                 }
 380
 381                 if (!dev && sk->sk_bound_dev_if) {
 382                         dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
 383                         if (!dev) {
 384                                 rcu_read_unlock();
 385                                 return -ENODEV;
 386                         }
 387                 }
 388                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 389                                                     scoped);
 390                 rcu_read_unlock();
 391
 392                 if (!(ipv6_can_nonlocal_bind(net, isk) || has_addr ||
 393                       addr_type == IPV6_ADDR_ANY))
 394                         return -EADDRNOTAVAIL;
 395
 396                 if (scoped)
 397                         sk->sk_bound_dev_if = addr->sin6_scope_id;
 398 #endif
 399         } else {
 400                 return -EAFNOSUPPORT;
 401         }
 402         return 0;
 403 }
 404
 405 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 406 {
 407         if (saddr->sa_family == AF_INET) {
 408                 struct inet_sock *isk = inet_sk(sk);
 409                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 410                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 411 #if IS_ENABLED(CONFIG_IPV6)
 412         } else if (saddr->sa_family == AF_INET6) {
 413                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 414                 struct ipv6_pinfo *np = inet6_sk(sk);
 415                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 416 #endif
 417         }
 418 }
 419
 420 /*
 421  * We need our own bind because there are no privileged id's == local ports.
 422  * Moreover, we don't allow binding to multi- and broadcast addresses.
 423  */
 424
 425 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 426 {
 427         struct inet_sock *isk = inet_sk(sk);
 428         unsigned short snum;
 429         int err;
 430         int dif = sk->sk_bound_dev_if;
 431
 432         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 433         if (err)
 434                 return err;
 435
 436         lock_sock(sk);
 437
 438         err = -EINVAL;
 439         if (isk->inet_num != 0)
 440                 goto out;
 441
 442         err = -EADDRINUSE;
 443         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 444         if (ping_get_port(sk, snum) != 0) {
 445                 /* Restore possibly modified sk->sk_bound_dev_if by ping_check_bind_addr(). */
 446                 sk->sk_bound_dev_if = dif;
 447                 goto out;
 448         }
 449         ping_set_saddr(sk, uaddr);
 450
 451         pr_debug("after bind(): num = %hu, dif = %d\n",
 452                  isk->inet_num,
 453                  sk->sk_bound_dev_if);
 454
 455         err = 0;
 456         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 457                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 458 #if IS_ENABLED(CONFIG_IPV6)
 459         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 460                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 461 #endif
 462
 463         if (snum)
 464                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 465         isk->inet_sport = htons(isk->inet_num);
 466         isk->inet_daddr = 0;
 467         isk->inet_dport = 0;
 468
 469 #if IS_ENABLED(CONFIG_IPV6)
 470         if (sk->sk_family == AF_INET6)
 471                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 472 #endif
 473
 474         sk_dst_reset(sk);
 475 out:
 476         release_sock(sk);
 477         pr_debug("ping_v4_bind -> %d\n", err);
 478         return err;
 479 }
 480 EXPORT_SYMBOL_GPL(ping_bind);
 481
 482 /*
 483  * Is this a supported type of ICMP message?
 484  */
 485
 486 static inline int ping_supported(int family, int type, int code)
 487 {
 488         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 489                (family == AF_INET && type == ICMP_EXT_ECHO && code == 0) ||
 490                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0) ||
 491                (family == AF_INET6 && type == ICMPV6_EXT_ECHO_REQUEST && code == 0);
 492 }
 493
 494 /*
 495  * This routine is called by the ICMP module when it gets some
 496  * sort of error condition.
 497  */
 498
 499 void ping_err(struct sk_buff *skb, int offset, u32 info)
 500 {
 501         int family;
 502         struct icmphdr *icmph;
 503         struct inet_sock *inet_sock;
 504         int type;
 505         int code;
 506         struct net *net = dev_net(skb->dev);
 507         struct sock *sk;
 508         int harderr;
 509         int err;
 510
 511         if (skb->protocol == htons(ETH_P_IP)) {
 512                 family = AF_INET;
 513                 type = icmp_hdr(skb)->type;
 514                 code = icmp_hdr(skb)->code;
 515                 icmph = (struct icmphdr *)(skb->data + offset);
 516         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 517                 family = AF_INET6;
 518                 type = icmp6_hdr(skb)->icmp6_type;
 519                 code = icmp6_hdr(skb)->icmp6_code;
 520                 icmph = (struct icmphdr *) (skb->data + offset);
 521         } else {
 522                 BUG();
 523         }
 524
 525         /* We assume the packet has already been checked by icmp_unreach */
 526
 527         if (!ping_supported(family, icmph->type, icmph->code))
 528                 return;
 529
 530         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 531                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
 532                  ntohs(icmph->un.echo.sequence));
 533
 534         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 535         if (!sk) {
 536                 pr_debug("no socket, dropping\n");
 537                 return; /* No socket for error */
 538         }
 539         pr_debug("err on socket %p\n", sk);
 540
 541         err = 0;
 542         harderr = 0;
 543         inet_sock = inet_sk(sk);
 544
 545         if (skb->protocol == htons(ETH_P_IP)) {
 546                 switch (type) {
 547                 default:
 548                 case ICMP_TIME_EXCEEDED:
 549                         err = EHOSTUNREACH;
 550                         break;
 551                 case ICMP_SOURCE_QUENCH:
 552                         /* This is not a real error but ping wants to see it.
 553                          * Report it with some fake errno.
 554                          */
 555                         err = EREMOTEIO;
 556                         break;
 557                 case ICMP_PARAMETERPROB:
 558                         err = EPROTO;
 559                         harderr = 1;
 560                         break;
 561                 case ICMP_DEST_UNREACH:
 562                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 563                                 ipv4_sk_update_pmtu(skb, sk, info);
 564                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 565                                         err = EMSGSIZE;
 566                                         harderr = 1;
 567                                         break;
 568                                 }
 569                                 goto out;
 570                         }
 571                         err = EHOSTUNREACH;
 572                         if (code <= NR_ICMP_UNREACH) {
 573                                 harderr = icmp_err_convert[code].fatal;
 574                                 err = icmp_err_convert[code].errno;
 575                         }
 576                         break;
 577                 case ICMP_REDIRECT:
 578                         /* See ICMP_SOURCE_QUENCH */
 579                         ipv4_sk_redirect(skb, sk);
 580                         err = EREMOTEIO;
 581                         break;
 582                 }
 583 #if IS_ENABLED(CONFIG_IPV6)
 584         } else if (skb->protocol == htons(ETH_P_IPV6)) {
 585                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 586 #endif
 587         }
 588
 589         /*
 590          *      RFC1122: OK.  Passes ICMP errors back to application, as per
 591          *      4.1.3.3.
 592          */
 593         if ((family == AF_INET && !inet_sock->recverr) ||
 594             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 595                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 596                         goto out;
 597         } else {
 598                 if (family == AF_INET) {
 599                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 600                                       info, (u8 *)icmph);
 601 #if IS_ENABLED(CONFIG_IPV6)
 602                 } else if (family == AF_INET6) {
 603                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 604                                                    info, (u8 *)icmph);
 605 #endif
 606                 }
 607         }
 608         sk->sk_err = err;
 609         sk_error_report(sk);
 610 out:
 611         return;
 612 }
 613 EXPORT_SYMBOL_GPL(ping_err);
 614
 615 /*
 616  *      Copy and checksum an ICMP Echo packet from user space into a buffer
 617  *      starting from the payload.
 618  */
 619
 620 int ping_getfrag(void *from, char *to,
 621                  int offset, int fraglen, int odd, struct sk_buff *skb)
 622 {
 623         struct pingfakehdr *pfh = from;
 624
 625         if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
 626                                           &pfh->msg->msg_iter))
 627                 return -EFAULT;
 628
 629 #if IS_ENABLED(CONFIG_IPV6)
 630         /* For IPv6, checksum each skb as we go along, as expected by
 631          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 632          * wcheck, it will be finalized in ping_v4_push_pending_frames.
 633          */
 634         if (pfh->family == AF_INET6) {
 635                 skb->csum = csum_block_add(skb->csum, pfh->wcheck, odd);
 636                 skb->ip_summed = CHECKSUM_NONE;
 637                 pfh->wcheck = 0;
 638         }
 639 #endif
 640
 641         return 0;
 642 }
 643 EXPORT_SYMBOL_GPL(ping_getfrag);
 644
 645 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 646                                        struct flowi4 *fl4)
 647 {
 648         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 649
 650         if (!skb)
 651                 return 0;
 652         pfh->wcheck = csum_partial((char *)&pfh->icmph,
 653                 sizeof(struct icmphdr), pfh->wcheck);
 654         pfh->icmph.checksum = csum_fold(pfh->wcheck);
 655         memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 656         skb->ip_summed = CHECKSUM_NONE;
 657         return ip_push_pending_frames(sk, fl4);
 658 }
 659
 660 int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 661                         void *user_icmph, size_t icmph_len)
 662 {
 663         u8 type, code;
 664
 665         if (len > 0xFFFF)
 666                 return -EMSGSIZE;
 667
 668         /* Must have at least a full ICMP header. */
 669         if (len < icmph_len)
 670                 return -EINVAL;
 671
 672         /*
 673          *      Check the flags.
 674          */
 675
 676         /* Mirror BSD error message compatibility */
 677         if (msg->msg_flags & MSG_OOB)
 678                 return -EOPNOTSUPP;
 679
 680         /*
 681          *      Fetch the ICMP header provided by the userland.
 682          *      iovec is modified! The ICMP header is consumed.
 683          */
 684         if (memcpy_from_msg(user_icmph, msg, icmph_len))
 685                 return -EFAULT;
 686
 687         if (family == AF_INET) {
 688                 type = ((struct icmphdr *) user_icmph)->type;
 689                 code = ((struct icmphdr *) user_icmph)->code;
 690 #if IS_ENABLED(CONFIG_IPV6)
 691         } else if (family == AF_INET6) {
 692                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 693                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 694 #endif
 695         } else {
 696                 BUG();
 697         }
 698
 699         if (!ping_supported(family, type, code))
 700                 return -EINVAL;
 701
 702         return 0;
 703 }
 704 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 705
 706 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 707 {
 708         struct net *net = sock_net(sk);
 709         struct flowi4 fl4;
 710         struct inet_sock *inet = inet_sk(sk);
 711         struct ipcm_cookie ipc;
 712         struct icmphdr user_icmph;
 713         struct pingfakehdr pfh;
 714         struct rtable *rt = NULL;
 715         struct ip_options_data opt_copy;
 716         int free = 0;
 717         __be32 saddr, daddr, faddr;
 718         u8  tos;
 719         int err;
 720
 721         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 722
 723         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 724                                   sizeof(user_icmph));
 725         if (err)
 726                 return err;
 727
 728         /*
 729          *      Get and verify the address.
 730          */
 731
 732         if (msg->msg_name) {
 733                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 734                 if (msg->msg_namelen < sizeof(*usin))
 735                         return -EINVAL;
 736                 if (usin->sin_family != AF_INET)
 737                         return -EAFNOSUPPORT;
 738                 daddr = usin->sin_addr.s_addr;
 739                 /* no remote port */
 740         } else {
 741                 if (sk->sk_state != TCP_ESTABLISHED)
 742                         return -EDESTADDRREQ;
 743                 daddr = inet->inet_daddr;
 744                 /* no remote port */
 745         }
 746
 747         ipcm_init_sk(&ipc, inet);
 748
 749         if (msg->msg_controllen) {
 750                 err = ip_cmsg_send(sk, msg, &ipc, false);
 751                 if (unlikely(err)) {
 752                         kfree(ipc.opt);
 753                         return err;
 754                 }
 755                 if (ipc.opt)
 756                         free = 1;
 757         }
 758         if (!ipc.opt) {
 759                 struct ip_options_rcu *inet_opt;
 760
 761                 rcu_read_lock();
 762                 inet_opt = rcu_dereference(inet->inet_opt);
 763                 if (inet_opt) {
 764                         memcpy(&opt_copy, inet_opt,
 765                                sizeof(*inet_opt) + inet_opt->opt.optlen);
 766                         ipc.opt = &opt_copy.opt;
 767                 }
 768                 rcu_read_unlock();
 769         }
 770
 771         saddr = ipc.addr;
 772         ipc.addr = faddr = daddr;
 773
 774         if (ipc.opt && ipc.opt->opt.srr) {
 775                 if (!daddr) {
 776                         err = -EINVAL;
 777                         goto out_free;
 778                 }
 779                 faddr = ipc.opt->opt.faddr;
 780         }
 781         tos = get_rttos(&ipc, inet);
 782         if (sock_flag(sk, SOCK_LOCALROUTE) ||
 783             (msg->msg_flags & MSG_DONTROUTE) ||
 784             (ipc.opt && ipc.opt->opt.is_strictroute)) {
 785                 tos |= RTO_ONLINK;
 786         }
 787
 788         if (ipv4_is_multicast(daddr)) {
 789                 if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
 790                         ipc.oif = inet->mc_index;
 791                 if (!saddr)
 792                         saddr = inet->mc_addr;
 793         } else if (!ipc.oif)
 794                 ipc.oif = inet->uc_index;
 795
 796         flowi4_init_output(&fl4, ipc.oif, ipc.sockc.mark, tos,
 797                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
 798                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
 799                            sk->sk_uid);
 800
 801         fl4.fl4_icmp_type = user_icmph.type;
 802         fl4.fl4_icmp_code = user_icmph.code;
 803
 804         security_sk_classify_flow(sk, flowi4_to_flowi_common(&fl4));
 805         rt = ip_route_output_flow(net, &fl4, sk);
 806         if (IS_ERR(rt)) {
 807                 err = PTR_ERR(rt);
 808                 rt = NULL;
 809                 if (err == -ENETUNREACH)
 810                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 811                 goto out;
 812         }
 813
 814         err = -EACCES;
 815         if ((rt->rt_flags & RTCF_BROADCAST) &&
 816             !sock_flag(sk, SOCK_BROADCAST))
 817                 goto out;
 818
 819         if (msg->msg_flags & MSG_CONFIRM)
 820                 goto do_confirm;
 821 back_from_confirm:
 822
 823         if (!ipc.addr)
 824                 ipc.addr = fl4.daddr;
 825
 826         lock_sock(sk);
 827
 828         pfh.icmph.type = user_icmph.type; /* already checked */
 829         pfh.icmph.code = user_icmph.code; /* ditto */
 830         pfh.icmph.checksum = 0;
 831         pfh.icmph.un.echo.id = inet->inet_sport;
 832         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 833         pfh.msg = msg;
 834         pfh.wcheck = 0;
 835         pfh.family = AF_INET;
 836
 837         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 838                              sizeof(struct icmphdr), &ipc, &rt,
 839                              msg->msg_flags);
 840         if (err)
 841                 ip_flush_pending_frames(sk);
 842         else
 843                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 844         release_sock(sk);
 845
 846 out:
 847         ip_rt_put(rt);
 848 out_free:
 849         if (free)
 850                 kfree(ipc.opt);
 851         if (!err) {
 852                 icmp_out_count(sock_net(sk), user_icmph.type);
 853                 return len;
 854         }
 855         return err;
 856
 857 do_confirm:
 858         if (msg->msg_flags & MSG_PROBE)
 859                 dst_confirm_neigh(&rt->dst, &fl4.daddr);
 860         if (!(msg->msg_flags & MSG_PROBE) || len)
 861                 goto back_from_confirm;
 862         err = 0;
 863         goto out;
 864 }
 865
 866 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
 867                  int *addr_len)
 868 {
 869         struct inet_sock *isk = inet_sk(sk);
 870         int family = sk->sk_family;
 871         struct sk_buff *skb;
 872         int copied, err;
 873
 874         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 875
 876         err = -EOPNOTSUPP;
 877         if (flags & MSG_OOB)
 878                 goto out;
 879
 880         if (flags & MSG_ERRQUEUE)
 881                 return inet_recv_error(sk, msg, len, addr_len);
 882
 883         skb = skb_recv_datagram(sk, flags, &err);
 884         if (!skb)
 885                 goto out;
 886
 887         copied = skb->len;
 888         if (copied > len) {
 889                 msg->msg_flags |= MSG_TRUNC;
 890                 copied = len;
 891         }
 892
 893         /* Don't bother checking the checksum */
 894         err = skb_copy_datagram_msg(skb, 0, msg, copied);
 895         if (err)
 896                 goto done;
 897
 898         sock_recv_timestamp(msg, sk, skb);
 899
 900         /* Copy the address and add cmsg data. */
 901         if (family == AF_INET) {
 902                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 903
 904                 if (sin) {
 905                         sin->sin_family = AF_INET;
 906                         sin->sin_port = 0 /* skb->h.uh->source */;
 907                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 908                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 909                         *addr_len = sizeof(*sin);
 910                 }
 911
 912                 if (isk->cmsg_flags)
 913                         ip_cmsg_recv(msg, skb);
 914
 915 #if IS_ENABLED(CONFIG_IPV6)
 916         } else if (family == AF_INET6) {
 917                 struct ipv6_pinfo *np = inet6_sk(sk);
 918                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
 919                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 920
 921                 if (sin6) {
 922                         sin6->sin6_family = AF_INET6;
 923                         sin6->sin6_port = 0;
 924                         sin6->sin6_addr = ip6->saddr;
 925                         sin6->sin6_flowinfo = 0;
 926                         if (np->sndflow)
 927                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 928                         sin6->sin6_scope_id =
 929                                 ipv6_iface_scope_id(&sin6->sin6_addr,
 930                                                     inet6_iif(skb));
 931                         *addr_len = sizeof(*sin6);
 932                 }
 933
 934                 if (inet6_sk(sk)->rxopt.all)
 935                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 936                 if (skb->protocol == htons(ETH_P_IPV6) &&
 937                     inet6_sk(sk)->rxopt.all)
 938                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 939                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 940                         ip_cmsg_recv(msg, skb);
 941 #endif
 942         } else {
 943                 BUG();
 944         }
 945
 946         err = copied;
 947
 948 done:
 949         skb_free_datagram(sk, skb);
 950 out:
 951         pr_debug("ping_recvmsg -> %d\n", err);
 952         return err;
 953 }
 954 EXPORT_SYMBOL_GPL(ping_recvmsg);
 955
 956 static enum skb_drop_reason __ping_queue_rcv_skb(struct sock *sk,
 957                                                  struct sk_buff *skb)
 958 {
 959         enum skb_drop_reason reason;
 960
 961         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 962                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
 963         if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
 964                 kfree_skb_reason(skb, reason);
 965                 pr_debug("ping_queue_rcv_skb -> failed\n");
 966                 return reason;
 967         }
 968         return SKB_NOT_DROPPED_YET;
 969 }
 970
 971 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 972 {
 973         return __ping_queue_rcv_skb(sk, skb) ? -1 : 0;
 974 }
 975 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 976
 977
 978 /*
 979  *      All we need to do is get the socket.
 980  */
 981
 982 enum skb_drop_reason ping_rcv(struct sk_buff *skb)
 983 {
 984         enum skb_drop_reason reason = SKB_DROP_REASON_NO_SOCKET;
 985         struct sock *sk;
 986         struct net *net = dev_net(skb->dev);
 987         struct icmphdr *icmph = icmp_hdr(skb);
 988
 989         /* We assume the packet has already been checked by icmp_rcv */
 990
 991         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 992                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 993
 994         /* Push ICMP header back */
 995         skb_push(skb, skb->data - (u8 *)icmph);
 996
 997         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 998         if (sk) {
 999                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
1000
1001                 pr_debug("rcv on socket %p\n", sk);
1002                 if (skb2)
1003                         reason = __ping_queue_rcv_skb(sk, skb2);
1004                 else
1005                         reason = SKB_DROP_REASON_NOMEM;
1006         }
1007
1008         if (reason)
1009                 pr_debug("no socket, dropping\n");
1010
1011         return reason;
1012 }
1013 EXPORT_SYMBOL_GPL(ping_rcv);
1014
1015 struct proto ping_prot = {
1016         .name =         "PING",
1017         .owner =        THIS_MODULE,
1018         .init =         ping_init_sock,
1019         .close =        ping_close,
1020         .pre_connect =  ping_pre_connect,
1021         .connect =      ip4_datagram_connect,
1022         .disconnect =   __udp_disconnect,
1023         .setsockopt =   ip_setsockopt,
1024         .getsockopt =   ip_getsockopt,
1025         .sendmsg =      ping_v4_sendmsg,
1026         .recvmsg =      ping_recvmsg,
1027         .bind =         ping_bind,
1028         .backlog_rcv =  ping_queue_rcv_skb,
1029         .release_cb =   ip4_datagram_release_cb,
1030         .hash =         ping_hash,
1031         .unhash =       ping_unhash,
1032         .get_port =     ping_get_port,
1033         .put_port =     ping_unhash,
1034         .obj_size =     sizeof(struct inet_sock),
1035 };
1036 EXPORT_SYMBOL(ping_prot);
1037
1038 #ifdef CONFIG_PROC_FS
1039
1040 static struct sock *ping_get_first(struct seq_file *seq, int start)
1041 {
1042         struct sock *sk;
1043         struct ping_iter_state *state = seq->private;
1044         struct net *net = seq_file_net(seq);
1045
1046         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1047              ++state->bucket) {
1048                 struct hlist_nulls_node *node;
1049                 struct hlist_nulls_head *hslot;
1050
1051                 hslot = &ping_table.hash[state->bucket];
1052
1053                 if (hlist_nulls_empty(hslot))
1054                         continue;
1055
1056                 sk_nulls_for_each(sk, node, hslot) {
1057                         if (net_eq(sock_net(sk), net) &&
1058                             sk->sk_family == state->family)
1059                                 goto found;
1060                 }
1061         }
1062         sk = NULL;
1063 found:
1064         return sk;
1065 }
1066
1067 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1068 {
1069         struct ping_iter_state *state = seq->private;
1070         struct net *net = seq_file_net(seq);
1071
1072         do {
1073                 sk = sk_nulls_next(sk);
1074         } while (sk && (!net_eq(sock_net(sk), net)));
1075
1076         if (!sk)
1077                 return ping_get_first(seq, state->bucket + 1);
1078         return sk;
1079 }
1080
1081 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1082 {
1083         struct sock *sk = ping_get_first(seq, 0);
1084
1085         if (sk)
1086                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1087                         --pos;
1088         return pos ? NULL : sk;
1089 }
1090
1091 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1092         __acquires(ping_table.lock)
1093 {
1094         struct ping_iter_state *state = seq->private;
1095         state->bucket = 0;
1096         state->family = family;
1097
1098         spin_lock(&ping_table.lock);
1099
1100         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1101 }
1102 EXPORT_SYMBOL_GPL(ping_seq_start);
1103
1104 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1105 {
1106         return ping_seq_start(seq, pos, AF_INET);
1107 }
1108
1109 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1110 {
1111         struct sock *sk;
1112
1113         if (v == SEQ_START_TOKEN)
1114                 sk = ping_get_idx(seq, 0);
1115         else
1116                 sk = ping_get_next(seq, v);
1117
1118         ++*pos;
1119         return sk;
1120 }
1121 EXPORT_SYMBOL_GPL(ping_seq_next);
1122
1123 void ping_seq_stop(struct seq_file *seq, void *v)
1124         __releases(ping_table.lock)
1125 {
1126         spin_unlock(&ping_table.lock);
1127 }
1128 EXPORT_SYMBOL_GPL(ping_seq_stop);
1129
1130 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1131                 int bucket)
1132 {
1133         struct inet_sock *inet = inet_sk(sp);
1134         __be32 dest = inet->inet_daddr;
1135         __be32 src = inet->inet_rcv_saddr;
1136         __u16 destp = ntohs(inet->inet_dport);
1137         __u16 srcp = ntohs(inet->inet_sport);
1138
1139         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1140                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
1141                 bucket, src, srcp, dest, destp, sp->sk_state,
1142                 sk_wmem_alloc_get(sp),
1143                 sk_rmem_alloc_get(sp),
1144                 0, 0L, 0,
1145                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1146                 0, sock_i_ino(sp),
1147                 refcount_read(&sp->sk_refcnt), sp,
1148                 atomic_read(&sp->sk_drops));
1149 }
1150
1151 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1152 {
1153         seq_setwidth(seq, 127);
1154         if (v == SEQ_START_TOKEN)
1155                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1156                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1157                            "inode ref pointer drops");
1158         else {
1159                 struct ping_iter_state *state = seq->private;
1160
1161                 ping_v4_format_sock(v, seq, state->bucket);
1162         }
1163         seq_pad(seq, '\n');
1164         return 0;
1165 }
1166
1167 static const struct seq_operations ping_v4_seq_ops = {
1168         .start          = ping_v4_seq_start,
1169         .show           = ping_v4_seq_show,
1170         .next           = ping_seq_next,
1171         .stop           = ping_seq_stop,
1172 };
1173
1174 static int __net_init ping_v4_proc_init_net(struct net *net)
1175 {
1176         if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
1177                         sizeof(struct ping_iter_state)))
1178                 return -ENOMEM;
1179         return 0;
1180 }
1181
1182 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1183 {
1184         remove_proc_entry("icmp", net->proc_net);
1185 }
1186
1187 static struct pernet_operations ping_v4_net_ops = {
1188         .init = ping_v4_proc_init_net,
1189         .exit = ping_v4_proc_exit_net,
1190 };
1191
1192 int __init ping_proc_init(void)
1193 {
1194         return register_pernet_subsys(&ping_v4_net_ops);
1195 }
1196
1197 void ping_proc_exit(void)
1198 {
1199         unregister_pernet_subsys(&ping_v4_net_ops);
1200 }
1201
1202 #endif
1203
1204 void __init ping_init(void)
1205 {
1206         int i;
1207
1208         for (i = 0; i < PING_HTABLE_SIZE; i++)
1209                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1210         spin_lock_init(&ping_table.lock);
1211 }