linux/net/ipv4/ping.c
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   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
  51struct ping_table {
  52        struct hlist_nulls_head hash[PING_HTABLE_SIZE];
  53        rwlock_t                lock;
  54};
  55
  56static struct ping_table ping_table;
  57struct pingv6_ops pingv6_ops;
  58EXPORT_SYMBOL_GPL(pingv6_ops);
  59
  60static u16 ping_port_rover;
  61
  62static 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}
  69EXPORT_SYMBOL_GPL(ping_hash);
  70
  71static 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
  77int 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;
 105next_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
 137fail:
 138        write_unlock_bh(&ping_table.lock);
 139        return 1;
 140}
 141EXPORT_SYMBOL_GPL(ping_get_port);
 142
 143int 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
 151void 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}
 167EXPORT_SYMBOL_GPL(ping_unhash);
 168
 169static 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;
 231exit:
 232        read_unlock_bh(&ping_table.lock);
 233
 234        return sk;
 235}
 236
 237static 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
 252int 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
 278out_release_group:
 279        put_group_info(group_info);
 280        return ret;
 281}
 282EXPORT_SYMBOL_GPL(ping_init_sock);
 283
 284void 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}
 292EXPORT_SYMBOL_GPL(ping_close);
 293
 294/* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 295static 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
 372static 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
 392int 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);
 442out:
 443        release_sock(sk);
 444        pr_debug("ping_v4_bind -> %d\n", err);
 445        return err;
 446}
 447EXPORT_SYMBOL_GPL(ping_bind);
 448
 449/*
 450 * Is this a supported type of ICMP message?
 451 */
 452
 453static 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
 466void 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_error_report(sk);
 577out:
 578        sock_put(sk);
 579}
 580EXPORT_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
 587int 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}
 622EXPORT_SYMBOL_GPL(ping_getfrag);
 623
 624static 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
 639int 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}
 683EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 684
 685static 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;
 800back_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
 824out:
 825        ip_rt_put(rt);
 826out_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
 835do_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
 844int 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
 926done:
 927        skb_free_datagram(sk, skb);
 928out:
 929        pr_debug("ping_recvmsg -> %d\n", err);
 930        return err;
 931}
 932EXPORT_SYMBOL_GPL(ping_recvmsg);
 933
 934int 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}
 945EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 946
 947
 948/*
 949 *      All we need to do is get the socket.
 950 */
 951
 952bool 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}
 982EXPORT_SYMBOL_GPL(ping_rcv);
 983
 984struct 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};
1003EXPORT_SYMBOL(ping_prot);
1004
1005#ifdef CONFIG_PROC_FS
1006
1007static 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;
1030found:
1031        return sk;
1032}
1033
1034static 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
1048static 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
1058void *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}
1069EXPORT_SYMBOL_GPL(ping_seq_start);
1070
1071static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1072{
1073        return ping_seq_start(seq, pos, AF_INET);
1074}
1075
1076void *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}
1088EXPORT_SYMBOL_GPL(ping_seq_next);
1089
1090void ping_seq_stop(struct seq_file *seq, void *v)
1091        __releases(ping_table.lock)
1092{
1093        read_unlock_bh(&ping_table.lock);
1094}
1095EXPORT_SYMBOL_GPL(ping_seq_stop);
1096
1097static 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
1118static 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
1134static 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
1141static 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
1149static void __net_exit ping_v4_proc_exit_net(struct net *net)
1150{
1151        remove_proc_entry("icmp", net->proc_net);
1152}
1153
1154static struct pernet_operations ping_v4_net_ops = {
1155        .init = ping_v4_proc_init_net,
1156        .exit = ping_v4_proc_exit_net,
1157};
1158
1159int __init ping_proc_init(void)
1160{
1161        return register_pernet_subsys(&ping_v4_net_ops);
1162}
1163
1164void ping_proc_exit(void)
1165{
1166        unregister_pernet_subsys(&ping_v4_net_ops);
1167}
1168
1169#endif
1170
1171void __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}
1179