linux/net/ipv4/ping.c
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   1/*
   2 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3 *              operating system.  INET is implemented using the  BSD Socket
   4 *              interface as the means of communication with the user level.
   5 *
   6 *              "Ping" sockets
   7 *
   8 *              This program is free software; you can redistribute it and/or
   9 *              modify it under the terms of the GNU General Public License
  10 *              as published by the Free Software Foundation; either version
  11 *              2 of the License, or (at your option) any later version.
  12 *
  13 * Based on ipv4/udp.c code.
  14 *
  15 * Authors:     Vasiliy Kulikov / Openwall (for Linux 2.6),
  16 *              Pavel Kankovsky (for Linux 2.4.32)
  17 *
  18 * Pavel gave all rights to bugs to Vasiliy,
  19 * none of the bugs are Pavel's now.
  20 *
  21 */
  22
  23#include <linux/uaccess.h>
  24#include <linux/types.h>
  25#include <linux/fcntl.h>
  26#include <linux/socket.h>
  27#include <linux/sockios.h>
  28#include <linux/in.h>
  29#include <linux/errno.h>
  30#include <linux/timer.h>
  31#include <linux/mm.h>
  32#include <linux/inet.h>
  33#include <linux/netdevice.h>
  34#include <net/snmp.h>
  35#include <net/ip.h>
  36#include <net/icmp.h>
  37#include <net/protocol.h>
  38#include <linux/skbuff.h>
  39#include <linux/proc_fs.h>
  40#include <linux/export.h>
  41#include <net/sock.h>
  42#include <net/ping.h>
  43#include <net/udp.h>
  44#include <net/route.h>
  45#include <net/inet_common.h>
  46#include <net/checksum.h>
  47
  48#if IS_ENABLED(CONFIG_IPV6)
  49#include <linux/in6.h>
  50#include <linux/icmpv6.h>
  51#include <net/addrconf.h>
  52#include <net/ipv6.h>
  53#include <net/transp_v6.h>
  54#endif
  55
  56struct ping_table {
  57        struct hlist_nulls_head hash[PING_HTABLE_SIZE];
  58        rwlock_t                lock;
  59};
  60
  61static struct ping_table ping_table;
  62struct pingv6_ops pingv6_ops;
  63EXPORT_SYMBOL_GPL(pingv6_ops);
  64
  65static u16 ping_port_rover;
  66
  67static inline u32 ping_hashfn(const struct net *net, u32 num, u32 mask)
  68{
  69        u32 res = (num + net_hash_mix(net)) & mask;
  70
  71        pr_debug("hash(%u) = %u\n", num, res);
  72        return res;
  73}
  74EXPORT_SYMBOL_GPL(ping_hash);
  75
  76static inline struct hlist_nulls_head *ping_hashslot(struct ping_table *table,
  77                                             struct net *net, unsigned int num)
  78{
  79        return &table->hash[ping_hashfn(net, num, PING_HTABLE_MASK)];
  80}
  81
  82int ping_get_port(struct sock *sk, unsigned short ident)
  83{
  84        struct hlist_nulls_node *node;
  85        struct hlist_nulls_head *hlist;
  86        struct inet_sock *isk, *isk2;
  87        struct sock *sk2 = NULL;
  88
  89        isk = inet_sk(sk);
  90        write_lock_bh(&ping_table.lock);
  91        if (ident == 0) {
  92                u32 i;
  93                u16 result = ping_port_rover + 1;
  94
  95                for (i = 0; i < (1L << 16); i++, result++) {
  96                        if (!result)
  97                                result++; /* avoid zero */
  98                        hlist = ping_hashslot(&ping_table, sock_net(sk),
  99                                            result);
 100                        ping_portaddr_for_each_entry(sk2, node, hlist) {
 101                                isk2 = inet_sk(sk2);
 102
 103                                if (isk2->inet_num == result)
 104                                        goto next_port;
 105                        }
 106
 107                        /* found */
 108                        ping_port_rover = ident = result;
 109                        break;
 110next_port:
 111                        ;
 112                }
 113                if (i >= (1L << 16))
 114                        goto fail;
 115        } else {
 116                hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
 117                ping_portaddr_for_each_entry(sk2, node, hlist) {
 118                        isk2 = inet_sk(sk2);
 119
 120                        /* BUG? Why is this reuse and not reuseaddr? ping.c
 121                         * doesn't turn off SO_REUSEADDR, and it doesn't expect
 122                         * that other ping processes can steal its packets.
 123                         */
 124                        if ((isk2->inet_num == ident) &&
 125                            (sk2 != sk) &&
 126                            (!sk2->sk_reuse || !sk->sk_reuse))
 127                                goto fail;
 128                }
 129        }
 130
 131        pr_debug("found port/ident = %d\n", ident);
 132        isk->inet_num = ident;
 133        if (sk_unhashed(sk)) {
 134                pr_debug("was not hashed\n");
 135                sock_hold(sk);
 136                hlist_nulls_add_head(&sk->sk_nulls_node, hlist);
 137                sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 138        }
 139        write_unlock_bh(&ping_table.lock);
 140        return 0;
 141
 142fail:
 143        write_unlock_bh(&ping_table.lock);
 144        return 1;
 145}
 146EXPORT_SYMBOL_GPL(ping_get_port);
 147
 148void ping_hash(struct sock *sk)
 149{
 150        pr_debug("ping_hash(sk->port=%u)\n", inet_sk(sk)->inet_num);
 151        BUG(); /* "Please do not press this button again." */
 152}
 153
 154void ping_unhash(struct sock *sk)
 155{
 156        struct inet_sock *isk = inet_sk(sk);
 157        pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
 158        if (sk_hashed(sk)) {
 159                write_lock_bh(&ping_table.lock);
 160                hlist_nulls_del(&sk->sk_nulls_node);
 161                sk_nulls_node_init(&sk->sk_nulls_node);
 162                sock_put(sk);
 163                isk->inet_num = 0;
 164                isk->inet_sport = 0;
 165                sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 166                write_unlock_bh(&ping_table.lock);
 167        }
 168}
 169EXPORT_SYMBOL_GPL(ping_unhash);
 170
 171static 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 = skb->dev->ifindex;
 178
 179        if (skb->protocol == htons(ETH_P_IP)) {
 180                pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
 181                         (int)ident, &ip_hdr(skb)->daddr, dif);
 182#if IS_ENABLED(CONFIG_IPV6)
 183        } else if (skb->protocol == htons(ETH_P_IPV6)) {
 184                pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
 185                         (int)ident, &ipv6_hdr(skb)->daddr, dif);
 186#endif
 187        }
 188
 189        read_lock_bh(&ping_table.lock);
 190
 191        ping_portaddr_for_each_entry(sk, hnode, hslot) {
 192                isk = inet_sk(sk);
 193
 194                pr_debug("iterate\n");
 195                if (isk->inet_num != ident)
 196                        continue;
 197
 198                if (skb->protocol == htons(ETH_P_IP) &&
 199                    sk->sk_family == AF_INET) {
 200                        pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
 201                                 (int) isk->inet_num, &isk->inet_rcv_saddr,
 202                                 sk->sk_bound_dev_if);
 203
 204                        if (isk->inet_rcv_saddr &&
 205                            isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
 206                                continue;
 207#if IS_ENABLED(CONFIG_IPV6)
 208                } else if (skb->protocol == htons(ETH_P_IPV6) &&
 209                           sk->sk_family == AF_INET6) {
 210
 211                        pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
 212                                 (int) isk->inet_num,
 213                                 &sk->sk_v6_rcv_saddr,
 214                                 sk->sk_bound_dev_if);
 215
 216                        if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
 217                            !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
 218                                             &ipv6_hdr(skb)->daddr))
 219                                continue;
 220#endif
 221                } else {
 222                        continue;
 223                }
 224
 225                if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
 226                        continue;
 227
 228                sock_hold(sk);
 229                goto exit;
 230        }
 231
 232        sk = NULL;
 233exit:
 234        read_unlock_bh(&ping_table.lock);
 235
 236        return sk;
 237}
 238
 239static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
 240                                          kgid_t *high)
 241{
 242        kgid_t *data = net->ipv4.ping_group_range.range;
 243        unsigned int seq;
 244
 245        do {
 246                seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
 247
 248                *low = data[0];
 249                *high = data[1];
 250        } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
 251}
 252
 253
 254int ping_init_sock(struct sock *sk)
 255{
 256        struct net *net = sock_net(sk);
 257        kgid_t group = current_egid();
 258        struct group_info *group_info;
 259        int i, j, count;
 260        kgid_t low, high;
 261        int ret = 0;
 262
 263        if (sk->sk_family == AF_INET6)
 264                sk->sk_ipv6only = 1;
 265
 266        inet_get_ping_group_range_net(net, &low, &high);
 267        if (gid_lte(low, group) && gid_lte(group, high))
 268                return 0;
 269
 270        group_info = get_current_groups();
 271        count = group_info->ngroups;
 272        for (i = 0; i < group_info->nblocks; i++) {
 273                int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
 274                for (j = 0; j < cp_count; j++) {
 275                        kgid_t gid = group_info->blocks[i][j];
 276                        if (gid_lte(low, gid) && gid_lte(gid, high))
 277                                goto out_release_group;
 278                }
 279
 280                count -= cp_count;
 281        }
 282
 283        ret = -EACCES;
 284
 285out_release_group:
 286        put_group_info(group_info);
 287        return ret;
 288}
 289EXPORT_SYMBOL_GPL(ping_init_sock);
 290
 291void ping_close(struct sock *sk, long timeout)
 292{
 293        pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 294                 inet_sk(sk), inet_sk(sk)->inet_num);
 295        pr_debug("isk->refcnt = %d\n", sk->sk_refcnt.counter);
 296
 297        sk_common_release(sk);
 298}
 299EXPORT_SYMBOL_GPL(ping_close);
 300
 301/* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
 302static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
 303                                struct sockaddr *uaddr, int addr_len) {
 304        struct net *net = sock_net(sk);
 305        if (sk->sk_family == AF_INET) {
 306                struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
 307                int chk_addr_ret;
 308
 309                if (addr_len < sizeof(*addr))
 310                        return -EINVAL;
 311
 312                if (addr->sin_family != AF_INET &&
 313                    !(addr->sin_family == AF_UNSPEC &&
 314                      addr->sin_addr.s_addr == htonl(INADDR_ANY)))
 315                        return -EAFNOSUPPORT;
 316
 317                pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
 318                         sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
 319
 320                chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
 321
 322                if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
 323                        chk_addr_ret = RTN_LOCAL;
 324
 325                if ((net->ipv4.sysctl_ip_nonlocal_bind == 0 &&
 326                    isk->freebind == 0 && isk->transparent == 0 &&
 327                     chk_addr_ret != RTN_LOCAL) ||
 328                    chk_addr_ret == RTN_MULTICAST ||
 329                    chk_addr_ret == RTN_BROADCAST)
 330                        return -EADDRNOTAVAIL;
 331
 332#if IS_ENABLED(CONFIG_IPV6)
 333        } else if (sk->sk_family == AF_INET6) {
 334                struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
 335                int addr_type, scoped, has_addr;
 336                struct net_device *dev = NULL;
 337
 338                if (addr_len < sizeof(*addr))
 339                        return -EINVAL;
 340
 341                if (addr->sin6_family != AF_INET6)
 342                        return -EAFNOSUPPORT;
 343
 344                pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
 345                         sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
 346
 347                addr_type = ipv6_addr_type(&addr->sin6_addr);
 348                scoped = __ipv6_addr_needs_scope_id(addr_type);
 349                if ((addr_type != IPV6_ADDR_ANY &&
 350                     !(addr_type & IPV6_ADDR_UNICAST)) ||
 351                    (scoped && !addr->sin6_scope_id))
 352                        return -EINVAL;
 353
 354                rcu_read_lock();
 355                if (addr->sin6_scope_id) {
 356                        dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
 357                        if (!dev) {
 358                                rcu_read_unlock();
 359                                return -ENODEV;
 360                        }
 361                }
 362                has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
 363                                                    scoped);
 364                rcu_read_unlock();
 365
 366                if (!(net->ipv6.sysctl.ip_nonlocal_bind ||
 367                      isk->freebind || isk->transparent || has_addr ||
 368                      addr_type == IPV6_ADDR_ANY))
 369                        return -EADDRNOTAVAIL;
 370
 371                if (scoped)
 372                        sk->sk_bound_dev_if = addr->sin6_scope_id;
 373#endif
 374        } else {
 375                return -EAFNOSUPPORT;
 376        }
 377        return 0;
 378}
 379
 380static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
 381{
 382        if (saddr->sa_family == AF_INET) {
 383                struct inet_sock *isk = inet_sk(sk);
 384                struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
 385                isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
 386#if IS_ENABLED(CONFIG_IPV6)
 387        } else if (saddr->sa_family == AF_INET6) {
 388                struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
 389                struct ipv6_pinfo *np = inet6_sk(sk);
 390                sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
 391#endif
 392        }
 393}
 394
 395static void ping_clear_saddr(struct sock *sk, int dif)
 396{
 397        sk->sk_bound_dev_if = dif;
 398        if (sk->sk_family == AF_INET) {
 399                struct inet_sock *isk = inet_sk(sk);
 400                isk->inet_rcv_saddr = isk->inet_saddr = 0;
 401#if IS_ENABLED(CONFIG_IPV6)
 402        } else if (sk->sk_family == AF_INET6) {
 403                struct ipv6_pinfo *np = inet6_sk(sk);
 404                memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
 405                memset(&np->saddr, 0, sizeof(np->saddr));
 406#endif
 407        }
 408}
 409/*
 410 * We need our own bind because there are no privileged id's == local ports.
 411 * Moreover, we don't allow binding to multi- and broadcast addresses.
 412 */
 413
 414int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 415{
 416        struct inet_sock *isk = inet_sk(sk);
 417        unsigned short snum;
 418        int err;
 419        int dif = sk->sk_bound_dev_if;
 420
 421        err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
 422        if (err)
 423                return err;
 424
 425        lock_sock(sk);
 426
 427        err = -EINVAL;
 428        if (isk->inet_num != 0)
 429                goto out;
 430
 431        err = -EADDRINUSE;
 432        ping_set_saddr(sk, uaddr);
 433        snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
 434        if (ping_get_port(sk, snum) != 0) {
 435                ping_clear_saddr(sk, dif);
 436                goto out;
 437        }
 438
 439        pr_debug("after bind(): num = %d, dif = %d\n",
 440                 (int)isk->inet_num,
 441                 (int)sk->sk_bound_dev_if);
 442
 443        err = 0;
 444        if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
 445                sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 446#if IS_ENABLED(CONFIG_IPV6)
 447        if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 448                sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
 449#endif
 450
 451        if (snum)
 452                sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
 453        isk->inet_sport = htons(isk->inet_num);
 454        isk->inet_daddr = 0;
 455        isk->inet_dport = 0;
 456
 457#if IS_ENABLED(CONFIG_IPV6)
 458        if (sk->sk_family == AF_INET6)
 459                memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
 460#endif
 461
 462        sk_dst_reset(sk);
 463out:
 464        release_sock(sk);
 465        pr_debug("ping_v4_bind -> %d\n", err);
 466        return err;
 467}
 468EXPORT_SYMBOL_GPL(ping_bind);
 469
 470/*
 471 * Is this a supported type of ICMP message?
 472 */
 473
 474static inline int ping_supported(int family, int type, int code)
 475{
 476        return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
 477               (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0);
 478}
 479
 480/*
 481 * This routine is called by the ICMP module when it gets some
 482 * sort of error condition.
 483 */
 484
 485void ping_err(struct sk_buff *skb, int offset, u32 info)
 486{
 487        int family;
 488        struct icmphdr *icmph;
 489        struct inet_sock *inet_sock;
 490        int type;
 491        int code;
 492        struct net *net = dev_net(skb->dev);
 493        struct sock *sk;
 494        int harderr;
 495        int err;
 496
 497        if (skb->protocol == htons(ETH_P_IP)) {
 498                family = AF_INET;
 499                type = icmp_hdr(skb)->type;
 500                code = icmp_hdr(skb)->code;
 501                icmph = (struct icmphdr *)(skb->data + offset);
 502        } else if (skb->protocol == htons(ETH_P_IPV6)) {
 503                family = AF_INET6;
 504                type = icmp6_hdr(skb)->icmp6_type;
 505                code = icmp6_hdr(skb)->icmp6_code;
 506                icmph = (struct icmphdr *) (skb->data + offset);
 507        } else {
 508                BUG();
 509        }
 510
 511        /* We assume the packet has already been checked by icmp_unreach */
 512
 513        if (!ping_supported(family, icmph->type, icmph->code))
 514                return;
 515
 516        pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
 517                 skb->protocol, type, code, ntohs(icmph->un.echo.id),
 518                 ntohs(icmph->un.echo.sequence));
 519
 520        sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 521        if (!sk) {
 522                pr_debug("no socket, dropping\n");
 523                return; /* No socket for error */
 524        }
 525        pr_debug("err on socket %p\n", sk);
 526
 527        err = 0;
 528        harderr = 0;
 529        inet_sock = inet_sk(sk);
 530
 531        if (skb->protocol == htons(ETH_P_IP)) {
 532                switch (type) {
 533                default:
 534                case ICMP_TIME_EXCEEDED:
 535                        err = EHOSTUNREACH;
 536                        break;
 537                case ICMP_SOURCE_QUENCH:
 538                        /* This is not a real error but ping wants to see it.
 539                         * Report it with some fake errno.
 540                         */
 541                        err = EREMOTEIO;
 542                        break;
 543                case ICMP_PARAMETERPROB:
 544                        err = EPROTO;
 545                        harderr = 1;
 546                        break;
 547                case ICMP_DEST_UNREACH:
 548                        if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 549                                ipv4_sk_update_pmtu(skb, sk, info);
 550                                if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 551                                        err = EMSGSIZE;
 552                                        harderr = 1;
 553                                        break;
 554                                }
 555                                goto out;
 556                        }
 557                        err = EHOSTUNREACH;
 558                        if (code <= NR_ICMP_UNREACH) {
 559                                harderr = icmp_err_convert[code].fatal;
 560                                err = icmp_err_convert[code].errno;
 561                        }
 562                        break;
 563                case ICMP_REDIRECT:
 564                        /* See ICMP_SOURCE_QUENCH */
 565                        ipv4_sk_redirect(skb, sk);
 566                        err = EREMOTEIO;
 567                        break;
 568                }
 569#if IS_ENABLED(CONFIG_IPV6)
 570        } else if (skb->protocol == htons(ETH_P_IPV6)) {
 571                harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
 572#endif
 573        }
 574
 575        /*
 576         *      RFC1122: OK.  Passes ICMP errors back to application, as per
 577         *      4.1.3.3.
 578         */
 579        if ((family == AF_INET && !inet_sock->recverr) ||
 580            (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
 581                if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 582                        goto out;
 583        } else {
 584                if (family == AF_INET) {
 585                        ip_icmp_error(sk, skb, err, 0 /* no remote port */,
 586                                      info, (u8 *)icmph);
 587#if IS_ENABLED(CONFIG_IPV6)
 588                } else if (family == AF_INET6) {
 589                        pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
 590                                                   info, (u8 *)icmph);
 591#endif
 592                }
 593        }
 594        sk->sk_err = err;
 595        sk->sk_error_report(sk);
 596out:
 597        sock_put(sk);
 598}
 599EXPORT_SYMBOL_GPL(ping_err);
 600
 601/*
 602 *      Copy and checksum an ICMP Echo packet from user space into a buffer
 603 *      starting from the payload.
 604 */
 605
 606int ping_getfrag(void *from, char *to,
 607                 int offset, int fraglen, int odd, struct sk_buff *skb)
 608{
 609        struct pingfakehdr *pfh = (struct pingfakehdr *)from;
 610
 611        if (offset == 0) {
 612                fraglen -= sizeof(struct icmphdr);
 613                if (fraglen < 0)
 614                        BUG();
 615                if (csum_and_copy_from_iter(to + sizeof(struct icmphdr),
 616                            fraglen, &pfh->wcheck,
 617                            &pfh->msg->msg_iter) != fraglen)
 618                        return -EFAULT;
 619        } else if (offset < sizeof(struct icmphdr)) {
 620                        BUG();
 621        } else {
 622                if (csum_and_copy_from_iter(to, fraglen, &pfh->wcheck,
 623                                            &pfh->msg->msg_iter) != fraglen)
 624                        return -EFAULT;
 625        }
 626
 627#if IS_ENABLED(CONFIG_IPV6)
 628        /* For IPv6, checksum each skb as we go along, as expected by
 629         * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
 630         * wcheck, it will be finalized in ping_v4_push_pending_frames.
 631         */
 632        if (pfh->family == AF_INET6) {
 633                skb->csum = pfh->wcheck;
 634                skb->ip_summed = CHECKSUM_NONE;
 635                pfh->wcheck = 0;
 636        }
 637#endif
 638
 639        return 0;
 640}
 641EXPORT_SYMBOL_GPL(ping_getfrag);
 642
 643static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
 644                                       struct flowi4 *fl4)
 645{
 646        struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
 647
 648        pfh->wcheck = csum_partial((char *)&pfh->icmph,
 649                sizeof(struct icmphdr), pfh->wcheck);
 650        pfh->icmph.checksum = csum_fold(pfh->wcheck);
 651        memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
 652        skb->ip_summed = CHECKSUM_NONE;
 653        return ip_push_pending_frames(sk, fl4);
 654}
 655
 656int ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 657                        void *user_icmph, size_t icmph_len) {
 658        u8 type, code;
 659
 660        if (len > 0xFFFF)
 661                return -EMSGSIZE;
 662
 663        /*
 664         *      Check the flags.
 665         */
 666
 667        /* Mirror BSD error message compatibility */
 668        if (msg->msg_flags & MSG_OOB)
 669                return -EOPNOTSUPP;
 670
 671        /*
 672         *      Fetch the ICMP header provided by the userland.
 673         *      iovec is modified! The ICMP header is consumed.
 674         */
 675        if (memcpy_from_msg(user_icmph, msg, icmph_len))
 676                return -EFAULT;
 677
 678        if (family == AF_INET) {
 679                type = ((struct icmphdr *) user_icmph)->type;
 680                code = ((struct icmphdr *) user_icmph)->code;
 681#if IS_ENABLED(CONFIG_IPV6)
 682        } else if (family == AF_INET6) {
 683                type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
 684                code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
 685#endif
 686        } else {
 687                BUG();
 688        }
 689
 690        if (!ping_supported(family, type, code))
 691                return -EINVAL;
 692
 693        return 0;
 694}
 695EXPORT_SYMBOL_GPL(ping_common_sendmsg);
 696
 697static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 698{
 699        struct net *net = sock_net(sk);
 700        struct flowi4 fl4;
 701        struct inet_sock *inet = inet_sk(sk);
 702        struct ipcm_cookie ipc;
 703        struct icmphdr user_icmph;
 704        struct pingfakehdr pfh;
 705        struct rtable *rt = NULL;
 706        struct ip_options_data opt_copy;
 707        int free = 0;
 708        __be32 saddr, daddr, faddr;
 709        u8  tos;
 710        int err;
 711
 712        pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
 713
 714        err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
 715                                  sizeof(user_icmph));
 716        if (err)
 717                return err;
 718
 719        /*
 720         *      Get and verify the address.
 721         */
 722
 723        if (msg->msg_name) {
 724                DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 725                if (msg->msg_namelen < sizeof(*usin))
 726                        return -EINVAL;
 727                if (usin->sin_family != AF_INET)
 728                        return -EAFNOSUPPORT;
 729                daddr = usin->sin_addr.s_addr;
 730                /* no remote port */
 731        } else {
 732                if (sk->sk_state != TCP_ESTABLISHED)
 733                        return -EDESTADDRREQ;
 734                daddr = inet->inet_daddr;
 735                /* no remote port */
 736        }
 737
 738        ipc.addr = inet->inet_saddr;
 739        ipc.opt = NULL;
 740        ipc.oif = sk->sk_bound_dev_if;
 741        ipc.tx_flags = 0;
 742        ipc.ttl = 0;
 743        ipc.tos = -1;
 744
 745        sock_tx_timestamp(sk, &ipc.tx_flags);
 746
 747        if (msg->msg_controllen) {
 748                err = ip_cmsg_send(sock_net(sk), msg, &ipc, false);
 749                if (err)
 750                        return err;
 751                if (ipc.opt)
 752                        free = 1;
 753        }
 754        if (!ipc.opt) {
 755                struct ip_options_rcu *inet_opt;
 756
 757                rcu_read_lock();
 758                inet_opt = rcu_dereference(inet->inet_opt);
 759                if (inet_opt) {
 760                        memcpy(&opt_copy, inet_opt,
 761                               sizeof(*inet_opt) + inet_opt->opt.optlen);
 762                        ipc.opt = &opt_copy.opt;
 763                }
 764                rcu_read_unlock();
 765        }
 766
 767        saddr = ipc.addr;
 768        ipc.addr = faddr = daddr;
 769
 770        if (ipc.opt && ipc.opt->opt.srr) {
 771                if (!daddr)
 772                        return -EINVAL;
 773                faddr = ipc.opt->opt.faddr;
 774        }
 775        tos = get_rttos(&ipc, inet);
 776        if (sock_flag(sk, SOCK_LOCALROUTE) ||
 777            (msg->msg_flags & MSG_DONTROUTE) ||
 778            (ipc.opt && ipc.opt->opt.is_strictroute)) {
 779                tos |= RTO_ONLINK;
 780        }
 781
 782        if (ipv4_is_multicast(daddr)) {
 783                if (!ipc.oif)
 784                        ipc.oif = inet->mc_index;
 785                if (!saddr)
 786                        saddr = inet->mc_addr;
 787        } else if (!ipc.oif)
 788                ipc.oif = inet->uc_index;
 789
 790        flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
 791                           RT_SCOPE_UNIVERSE, sk->sk_protocol,
 792                           inet_sk_flowi_flags(sk), faddr, saddr, 0, 0);
 793
 794        security_sk_classify_flow(sk, flowi4_to_flowi(&fl4));
 795        rt = ip_route_output_flow(net, &fl4, sk);
 796        if (IS_ERR(rt)) {
 797                err = PTR_ERR(rt);
 798                rt = NULL;
 799                if (err == -ENETUNREACH)
 800                        IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
 801                goto out;
 802        }
 803
 804        err = -EACCES;
 805        if ((rt->rt_flags & RTCF_BROADCAST) &&
 806            !sock_flag(sk, SOCK_BROADCAST))
 807                goto out;
 808
 809        if (msg->msg_flags & MSG_CONFIRM)
 810                goto do_confirm;
 811back_from_confirm:
 812
 813        if (!ipc.addr)
 814                ipc.addr = fl4.daddr;
 815
 816        lock_sock(sk);
 817
 818        pfh.icmph.type = user_icmph.type; /* already checked */
 819        pfh.icmph.code = user_icmph.code; /* ditto */
 820        pfh.icmph.checksum = 0;
 821        pfh.icmph.un.echo.id = inet->inet_sport;
 822        pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
 823        pfh.msg = msg;
 824        pfh.wcheck = 0;
 825        pfh.family = AF_INET;
 826
 827        err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
 828                        0, &ipc, &rt, msg->msg_flags);
 829        if (err)
 830                ip_flush_pending_frames(sk);
 831        else
 832                err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
 833        release_sock(sk);
 834
 835out:
 836        ip_rt_put(rt);
 837        if (free)
 838                kfree(ipc.opt);
 839        if (!err) {
 840                icmp_out_count(sock_net(sk), user_icmph.type);
 841                return len;
 842        }
 843        return err;
 844
 845do_confirm:
 846        dst_confirm(&rt->dst);
 847        if (!(msg->msg_flags & MSG_PROBE) || len)
 848                goto back_from_confirm;
 849        err = 0;
 850        goto out;
 851}
 852
 853int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 854                 int flags, int *addr_len)
 855{
 856        struct inet_sock *isk = inet_sk(sk);
 857        int family = sk->sk_family;
 858        struct sk_buff *skb;
 859        int copied, err;
 860
 861        pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
 862
 863        err = -EOPNOTSUPP;
 864        if (flags & MSG_OOB)
 865                goto out;
 866
 867        if (flags & MSG_ERRQUEUE)
 868                return inet_recv_error(sk, msg, len, addr_len);
 869
 870        skb = skb_recv_datagram(sk, flags, noblock, &err);
 871        if (!skb)
 872                goto out;
 873
 874        copied = skb->len;
 875        if (copied > len) {
 876                msg->msg_flags |= MSG_TRUNC;
 877                copied = len;
 878        }
 879
 880        /* Don't bother checking the checksum */
 881        err = skb_copy_datagram_msg(skb, 0, msg, copied);
 882        if (err)
 883                goto done;
 884
 885        sock_recv_timestamp(msg, sk, skb);
 886
 887        /* Copy the address and add cmsg data. */
 888        if (family == AF_INET) {
 889                DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 890
 891                if (sin) {
 892                        sin->sin_family = AF_INET;
 893                        sin->sin_port = 0 /* skb->h.uh->source */;
 894                        sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
 895                        memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 896                        *addr_len = sizeof(*sin);
 897                }
 898
 899                if (isk->cmsg_flags)
 900                        ip_cmsg_recv(msg, skb);
 901
 902#if IS_ENABLED(CONFIG_IPV6)
 903        } else if (family == AF_INET6) {
 904                struct ipv6_pinfo *np = inet6_sk(sk);
 905                struct ipv6hdr *ip6 = ipv6_hdr(skb);
 906                DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
 907
 908                if (sin6) {
 909                        sin6->sin6_family = AF_INET6;
 910                        sin6->sin6_port = 0;
 911                        sin6->sin6_addr = ip6->saddr;
 912                        sin6->sin6_flowinfo = 0;
 913                        if (np->sndflow)
 914                                sin6->sin6_flowinfo = ip6_flowinfo(ip6);
 915                        sin6->sin6_scope_id =
 916                                ipv6_iface_scope_id(&sin6->sin6_addr,
 917                                                    inet6_iif(skb));
 918                        *addr_len = sizeof(*sin6);
 919                }
 920
 921                if (inet6_sk(sk)->rxopt.all)
 922                        pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
 923                if (skb->protocol == htons(ETH_P_IPV6) &&
 924                    inet6_sk(sk)->rxopt.all)
 925                        pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
 926                else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
 927                        ip_cmsg_recv(msg, skb);
 928#endif
 929        } else {
 930                BUG();
 931        }
 932
 933        err = copied;
 934
 935done:
 936        skb_free_datagram(sk, skb);
 937out:
 938        pr_debug("ping_recvmsg -> %d\n", err);
 939        return err;
 940}
 941EXPORT_SYMBOL_GPL(ping_recvmsg);
 942
 943int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 944{
 945        pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 946                 inet_sk(sk), inet_sk(sk)->inet_num, skb);
 947        if (sock_queue_rcv_skb(sk, skb) < 0) {
 948                kfree_skb(skb);
 949                pr_debug("ping_queue_rcv_skb -> failed\n");
 950                return -1;
 951        }
 952        return 0;
 953}
 954EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
 955
 956
 957/*
 958 *      All we need to do is get the socket.
 959 */
 960
 961bool ping_rcv(struct sk_buff *skb)
 962{
 963        struct sock *sk;
 964        struct net *net = dev_net(skb->dev);
 965        struct icmphdr *icmph = icmp_hdr(skb);
 966
 967        /* We assume the packet has already been checked by icmp_rcv */
 968
 969        pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
 970                 skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
 971
 972        /* Push ICMP header back */
 973        skb_push(skb, skb->data - (u8 *)icmph);
 974
 975        sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
 976        if (sk) {
 977                struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 978
 979                pr_debug("rcv on socket %p\n", sk);
 980                if (skb2)
 981                        ping_queue_rcv_skb(sk, skb2);
 982                sock_put(sk);
 983                return true;
 984        }
 985        pr_debug("no socket, dropping\n");
 986
 987        return false;
 988}
 989EXPORT_SYMBOL_GPL(ping_rcv);
 990
 991struct proto ping_prot = {
 992        .name =         "PING",
 993        .owner =        THIS_MODULE,
 994        .init =         ping_init_sock,
 995        .close =        ping_close,
 996        .connect =      ip4_datagram_connect,
 997        .disconnect =   udp_disconnect,
 998        .setsockopt =   ip_setsockopt,
 999        .getsockopt =   ip_getsockopt,
1000        .sendmsg =      ping_v4_sendmsg,
1001        .recvmsg =      ping_recvmsg,
1002        .bind =         ping_bind,
1003        .backlog_rcv =  ping_queue_rcv_skb,
1004        .release_cb =   ip4_datagram_release_cb,
1005        .hash =         ping_hash,
1006        .unhash =       ping_unhash,
1007        .get_port =     ping_get_port,
1008        .obj_size =     sizeof(struct inet_sock),
1009};
1010EXPORT_SYMBOL(ping_prot);
1011
1012#ifdef CONFIG_PROC_FS
1013
1014static struct sock *ping_get_first(struct seq_file *seq, int start)
1015{
1016        struct sock *sk;
1017        struct ping_iter_state *state = seq->private;
1018        struct net *net = seq_file_net(seq);
1019
1020        for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1021             ++state->bucket) {
1022                struct hlist_nulls_node *node;
1023                struct hlist_nulls_head *hslot;
1024
1025                hslot = &ping_table.hash[state->bucket];
1026
1027                if (hlist_nulls_empty(hslot))
1028                        continue;
1029
1030                sk_nulls_for_each(sk, node, hslot) {
1031                        if (net_eq(sock_net(sk), net) &&
1032                            sk->sk_family == state->family)
1033                                goto found;
1034                }
1035        }
1036        sk = NULL;
1037found:
1038        return sk;
1039}
1040
1041static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1042{
1043        struct ping_iter_state *state = seq->private;
1044        struct net *net = seq_file_net(seq);
1045
1046        do {
1047                sk = sk_nulls_next(sk);
1048        } while (sk && (!net_eq(sock_net(sk), net)));
1049
1050        if (!sk)
1051                return ping_get_first(seq, state->bucket + 1);
1052        return sk;
1053}
1054
1055static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1056{
1057        struct sock *sk = ping_get_first(seq, 0);
1058
1059        if (sk)
1060                while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1061                        --pos;
1062        return pos ? NULL : sk;
1063}
1064
1065void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1066{
1067        struct ping_iter_state *state = seq->private;
1068        state->bucket = 0;
1069        state->family = family;
1070
1071        read_lock_bh(&ping_table.lock);
1072
1073        return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1074}
1075EXPORT_SYMBOL_GPL(ping_seq_start);
1076
1077static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1078{
1079        return ping_seq_start(seq, pos, AF_INET);
1080}
1081
1082void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1083{
1084        struct sock *sk;
1085
1086        if (v == SEQ_START_TOKEN)
1087                sk = ping_get_idx(seq, 0);
1088        else
1089                sk = ping_get_next(seq, v);
1090
1091        ++*pos;
1092        return sk;
1093}
1094EXPORT_SYMBOL_GPL(ping_seq_next);
1095
1096void ping_seq_stop(struct seq_file *seq, void *v)
1097{
1098        read_unlock_bh(&ping_table.lock);
1099}
1100EXPORT_SYMBOL_GPL(ping_seq_stop);
1101
1102static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1103                int bucket)
1104{
1105        struct inet_sock *inet = inet_sk(sp);
1106        __be32 dest = inet->inet_daddr;
1107        __be32 src = inet->inet_rcv_saddr;
1108        __u16 destp = ntohs(inet->inet_dport);
1109        __u16 srcp = ntohs(inet->inet_sport);
1110
1111        seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1112                " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
1113                bucket, src, srcp, dest, destp, sp->sk_state,
1114                sk_wmem_alloc_get(sp),
1115                sk_rmem_alloc_get(sp),
1116                0, 0L, 0,
1117                from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1118                0, sock_i_ino(sp),
1119                atomic_read(&sp->sk_refcnt), sp,
1120                atomic_read(&sp->sk_drops));
1121}
1122
1123static int ping_v4_seq_show(struct seq_file *seq, void *v)
1124{
1125        seq_setwidth(seq, 127);
1126        if (v == SEQ_START_TOKEN)
1127                seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1128                           "rx_queue tr tm->when retrnsmt   uid  timeout "
1129                           "inode ref pointer drops");
1130        else {
1131                struct ping_iter_state *state = seq->private;
1132
1133                ping_v4_format_sock(v, seq, state->bucket);
1134        }
1135        seq_pad(seq, '\n');
1136        return 0;
1137}
1138
1139static const struct seq_operations ping_v4_seq_ops = {
1140        .show           = ping_v4_seq_show,
1141        .start          = ping_v4_seq_start,
1142        .next           = ping_seq_next,
1143        .stop           = ping_seq_stop,
1144};
1145
1146static int ping_seq_open(struct inode *inode, struct file *file)
1147{
1148        struct ping_seq_afinfo *afinfo = PDE_DATA(inode);
1149        return seq_open_net(inode, file, &afinfo->seq_ops,
1150                           sizeof(struct ping_iter_state));
1151}
1152
1153const struct file_operations ping_seq_fops = {
1154        .open           = ping_seq_open,
1155        .read           = seq_read,
1156        .llseek         = seq_lseek,
1157        .release        = seq_release_net,
1158};
1159EXPORT_SYMBOL_GPL(ping_seq_fops);
1160
1161static struct ping_seq_afinfo ping_v4_seq_afinfo = {
1162        .name           = "icmp",
1163        .family         = AF_INET,
1164        .seq_fops       = &ping_seq_fops,
1165        .seq_ops        = {
1166                .start          = ping_v4_seq_start,
1167                .show           = ping_v4_seq_show,
1168                .next           = ping_seq_next,
1169                .stop           = ping_seq_stop,
1170        },
1171};
1172
1173int ping_proc_register(struct net *net, struct ping_seq_afinfo *afinfo)
1174{
1175        struct proc_dir_entry *p;
1176        p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
1177                             afinfo->seq_fops, afinfo);
1178        if (!p)
1179                return -ENOMEM;
1180        return 0;
1181}
1182EXPORT_SYMBOL_GPL(ping_proc_register);
1183
1184void ping_proc_unregister(struct net *net, struct ping_seq_afinfo *afinfo)
1185{
1186        remove_proc_entry(afinfo->name, net->proc_net);
1187}
1188EXPORT_SYMBOL_GPL(ping_proc_unregister);
1189
1190static int __net_init ping_v4_proc_init_net(struct net *net)
1191{
1192        return ping_proc_register(net, &ping_v4_seq_afinfo);
1193}
1194
1195static void __net_exit ping_v4_proc_exit_net(struct net *net)
1196{
1197        ping_proc_unregister(net, &ping_v4_seq_afinfo);
1198}
1199
1200static struct pernet_operations ping_v4_net_ops = {
1201        .init = ping_v4_proc_init_net,
1202        .exit = ping_v4_proc_exit_net,
1203};
1204
1205int __init ping_proc_init(void)
1206{
1207        return register_pernet_subsys(&ping_v4_net_ops);
1208}
1209
1210void ping_proc_exit(void)
1211{
1212        unregister_pernet_subsys(&ping_v4_net_ops);
1213}
1214
1215#endif
1216
1217void __init ping_init(void)
1218{
1219        int i;
1220
1221        for (i = 0; i < PING_HTABLE_SIZE; i++)
1222                INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1223        rwlock_init(&ping_table.lock);
1224}
1225