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TOMOYO Linux Cross Reference
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 
 56 struct ping_table {
 57         struct hlist_nulls_head hash[PING_HTABLE_SIZE];
 58         rwlock_t                lock;
 59 };
 60 
 61 static struct ping_table ping_table;
 62 struct pingv6_ops pingv6_ops;
 63 EXPORT_SYMBOL_GPL(pingv6_ops);
 64 
 65 static u16 ping_port_rover;
 66 
 67 static 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 }
 74 EXPORT_SYMBOL_GPL(ping_hash);
 75 
 76 static 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 
 82 int 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;
110 next_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 
142 fail:
143         write_unlock_bh(&ping_table.lock);
144         return 1;
145 }
146 EXPORT_SYMBOL_GPL(ping_get_port);
147 
148 int 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         return 0;
154 }
155 
156 void ping_unhash(struct sock *sk)
157 {
158         struct inet_sock *isk = inet_sk(sk);
159 
160         pr_debug("ping_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
161         write_lock_bh(&ping_table.lock);
162         if (sk_hashed(sk)) {
163                 hlist_nulls_del(&sk->sk_nulls_node);
164                 sk_nulls_node_init(&sk->sk_nulls_node);
165                 sock_put(sk);
166                 isk->inet_num = 0;
167                 isk->inet_sport = 0;
168                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
169         }
170         write_unlock_bh(&ping_table.lock);
171 }
172 EXPORT_SYMBOL_GPL(ping_unhash);
173 
174 static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
175 {
176         struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
177         struct sock *sk = NULL;
178         struct inet_sock *isk;
179         struct hlist_nulls_node *hnode;
180         int dif = skb->dev->ifindex;
181 
182         if (skb->protocol == htons(ETH_P_IP)) {
183                 pr_debug("try to find: num = %d, daddr = %pI4, dif = %d\n",
184                          (int)ident, &ip_hdr(skb)->daddr, dif);
185 #if IS_ENABLED(CONFIG_IPV6)
186         } else if (skb->protocol == htons(ETH_P_IPV6)) {
187                 pr_debug("try to find: num = %d, daddr = %pI6c, dif = %d\n",
188                          (int)ident, &ipv6_hdr(skb)->daddr, dif);
189 #endif
190         }
191 
192         read_lock_bh(&ping_table.lock);
193 
194         ping_portaddr_for_each_entry(sk, hnode, hslot) {
195                 isk = inet_sk(sk);
196 
197                 pr_debug("iterate\n");
198                 if (isk->inet_num != ident)
199                         continue;
200 
201                 if (skb->protocol == htons(ETH_P_IP) &&
202                     sk->sk_family == AF_INET) {
203                         pr_debug("found: %p: num=%d, daddr=%pI4, dif=%d\n", sk,
204                                  (int) isk->inet_num, &isk->inet_rcv_saddr,
205                                  sk->sk_bound_dev_if);
206 
207                         if (isk->inet_rcv_saddr &&
208                             isk->inet_rcv_saddr != ip_hdr(skb)->daddr)
209                                 continue;
210 #if IS_ENABLED(CONFIG_IPV6)
211                 } else if (skb->protocol == htons(ETH_P_IPV6) &&
212                            sk->sk_family == AF_INET6) {
213 
214                         pr_debug("found: %p: num=%d, daddr=%pI6c, dif=%d\n", sk,
215                                  (int) isk->inet_num,
216                                  &sk->sk_v6_rcv_saddr,
217                                  sk->sk_bound_dev_if);
218 
219                         if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
220                             !ipv6_addr_equal(&sk->sk_v6_rcv_saddr,
221                                              &ipv6_hdr(skb)->daddr))
222                                 continue;
223 #endif
224                 } else {
225                         continue;
226                 }
227 
228                 if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
229                         continue;
230 
231                 sock_hold(sk);
232                 goto exit;
233         }
234 
235         sk = NULL;
236 exit:
237         read_unlock_bh(&ping_table.lock);
238 
239         return sk;
240 }
241 
242 static void inet_get_ping_group_range_net(struct net *net, kgid_t *low,
243                                           kgid_t *high)
244 {
245         kgid_t *data = net->ipv4.ping_group_range.range;
246         unsigned int seq;
247 
248         do {
249                 seq = read_seqbegin(&net->ipv4.ping_group_range.lock);
250 
251                 *low = data[0];
252                 *high = data[1];
253         } while (read_seqretry(&net->ipv4.ping_group_range.lock, seq));
254 }
255 
256 
257 int ping_init_sock(struct sock *sk)
258 {
259         struct net *net = sock_net(sk);
260         kgid_t group = current_egid();
261         struct group_info *group_info;
262         int i;
263         kgid_t low, high;
264         int ret = 0;
265 
266         if (sk->sk_family == AF_INET6)
267                 sk->sk_ipv6only = 1;
268 
269         inet_get_ping_group_range_net(net, &low, &high);
270         if (gid_lte(low, group) && gid_lte(group, high))
271                 return 0;
272 
273         group_info = get_current_groups();
274         for (i = 0; i < group_info->ngroups; i++) {
275                 kgid_t gid = group_info->gid[i];
276 
277                 if (gid_lte(low, gid) && gid_lte(gid, high))
278                         goto out_release_group;
279         }
280 
281         ret = -EACCES;
282 
283 out_release_group:
284         put_group_info(group_info);
285         return ret;
286 }
287 EXPORT_SYMBOL_GPL(ping_init_sock);
288 
289 void ping_close(struct sock *sk, long timeout)
290 {
291         pr_debug("ping_close(sk=%p,sk->num=%u)\n",
292                  inet_sk(sk), inet_sk(sk)->inet_num);
293         pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
294 
295         sk_common_release(sk);
296 }
297 EXPORT_SYMBOL_GPL(ping_close);
298 
299 /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
300 static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
301                                 struct sockaddr *uaddr, int addr_len) {
302         struct net *net = sock_net(sk);
303         if (sk->sk_family == AF_INET) {
304                 struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
305                 int chk_addr_ret;
306 
307                 if (addr_len < sizeof(*addr))
308                         return -EINVAL;
309 
310                 if (addr->sin_family != AF_INET &&
311                     !(addr->sin_family == AF_UNSPEC &&
312                       addr->sin_addr.s_addr == htonl(INADDR_ANY)))
313                         return -EAFNOSUPPORT;
314 
315                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
316                          sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
317 
318                 chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
319 
320                 if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
321                         chk_addr_ret = RTN_LOCAL;
322 
323                 if ((net->ipv4.sysctl_ip_nonlocal_bind == 0 &&
324                     isk->freebind == 0 && isk->transparent == 0 &&
325                      chk_addr_ret != RTN_LOCAL) ||
326                     chk_addr_ret == RTN_MULTICAST ||
327                     chk_addr_ret == RTN_BROADCAST)
328                         return -EADDRNOTAVAIL;
329 
330 #if IS_ENABLED(CONFIG_IPV6)
331         } else if (sk->sk_family == AF_INET6) {
332                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) uaddr;
333                 int addr_type, scoped, has_addr;
334                 struct net_device *dev = NULL;
335 
336                 if (addr_len < sizeof(*addr))
337                         return -EINVAL;
338 
339                 if (addr->sin6_family != AF_INET6)
340                         return -EAFNOSUPPORT;
341 
342                 pr_debug("ping_check_bind_addr(sk=%p,addr=%pI6c,port=%d)\n",
343                          sk, addr->sin6_addr.s6_addr, ntohs(addr->sin6_port));
344 
345                 addr_type = ipv6_addr_type(&addr->sin6_addr);
346                 scoped = __ipv6_addr_needs_scope_id(addr_type);
347                 if ((addr_type != IPV6_ADDR_ANY &&
348                      !(addr_type & IPV6_ADDR_UNICAST)) ||
349                     (scoped && !addr->sin6_scope_id))
350                         return -EINVAL;
351 
352                 rcu_read_lock();
353                 if (addr->sin6_scope_id) {
354                         dev = dev_get_by_index_rcu(net, addr->sin6_scope_id);
355                         if (!dev) {
356                                 rcu_read_unlock();
357                                 return -ENODEV;
358                         }
359                 }
360                 has_addr = pingv6_ops.ipv6_chk_addr(net, &addr->sin6_addr, dev,
361                                                     scoped);
362                 rcu_read_unlock();
363 
364                 if (!(net->ipv6.sysctl.ip_nonlocal_bind ||
365                       isk->freebind || isk->transparent || has_addr ||
366                       addr_type == IPV6_ADDR_ANY))
367                         return -EADDRNOTAVAIL;
368 
369                 if (scoped)
370                         sk->sk_bound_dev_if = addr->sin6_scope_id;
371 #endif
372         } else {
373                 return -EAFNOSUPPORT;
374         }
375         return 0;
376 }
377 
378 static void ping_set_saddr(struct sock *sk, struct sockaddr *saddr)
379 {
380         if (saddr->sa_family == AF_INET) {
381                 struct inet_sock *isk = inet_sk(sk);
382                 struct sockaddr_in *addr = (struct sockaddr_in *) saddr;
383                 isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
384 #if IS_ENABLED(CONFIG_IPV6)
385         } else if (saddr->sa_family == AF_INET6) {
386                 struct sockaddr_in6 *addr = (struct sockaddr_in6 *) saddr;
387                 struct ipv6_pinfo *np = inet6_sk(sk);
388                 sk->sk_v6_rcv_saddr = np->saddr = addr->sin6_addr;
389 #endif
390         }
391 }
392 
393 static void ping_clear_saddr(struct sock *sk, int dif)
394 {
395         sk->sk_bound_dev_if = dif;
396         if (sk->sk_family == AF_INET) {
397                 struct inet_sock *isk = inet_sk(sk);
398                 isk->inet_rcv_saddr = isk->inet_saddr = 0;
399 #if IS_ENABLED(CONFIG_IPV6)
400         } else if (sk->sk_family == AF_INET6) {
401                 struct ipv6_pinfo *np = inet6_sk(sk);
402                 memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
403                 memset(&np->saddr, 0, sizeof(np->saddr));
404 #endif
405         }
406 }
407 /*
408  * We need our own bind because there are no privileged id's == local ports.
409  * Moreover, we don't allow binding to multi- and broadcast addresses.
410  */
411 
412 int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
413 {
414         struct inet_sock *isk = inet_sk(sk);
415         unsigned short snum;
416         int err;
417         int dif = sk->sk_bound_dev_if;
418 
419         err = ping_check_bind_addr(sk, isk, uaddr, addr_len);
420         if (err)
421                 return err;
422 
423         lock_sock(sk);
424 
425         err = -EINVAL;
426         if (isk->inet_num != 0)
427                 goto out;
428 
429         err = -EADDRINUSE;
430         ping_set_saddr(sk, uaddr);
431         snum = ntohs(((struct sockaddr_in *)uaddr)->sin_port);
432         if (ping_get_port(sk, snum) != 0) {
433                 ping_clear_saddr(sk, dif);
434                 goto out;
435         }
436 
437         pr_debug("after bind(): num = %hu, dif = %d\n",
438                  isk->inet_num,
439                  sk->sk_bound_dev_if);
440 
441         err = 0;
442         if (sk->sk_family == AF_INET && isk->inet_rcv_saddr)
443                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
444 #if IS_ENABLED(CONFIG_IPV6)
445         if (sk->sk_family == AF_INET6 && !ipv6_addr_any(&sk->sk_v6_rcv_saddr))
446                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
447 #endif
448 
449         if (snum)
450                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
451         isk->inet_sport = htons(isk->inet_num);
452         isk->inet_daddr = 0;
453         isk->inet_dport = 0;
454 
455 #if IS_ENABLED(CONFIG_IPV6)
456         if (sk->sk_family == AF_INET6)
457                 memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
458 #endif
459 
460         sk_dst_reset(sk);
461 out:
462         release_sock(sk);
463         pr_debug("ping_v4_bind -> %d\n", err);
464         return err;
465 }
466 EXPORT_SYMBOL_GPL(ping_bind);
467 
468 /*
469  * Is this a supported type of ICMP message?
470  */
471 
472 static inline int ping_supported(int family, int type, int code)
473 {
474         return (family == AF_INET && type == ICMP_ECHO && code == 0) ||
475                (family == AF_INET6 && type == ICMPV6_ECHO_REQUEST && code == 0);
476 }
477 
478 /*
479  * This routine is called by the ICMP module when it gets some
480  * sort of error condition.
481  */
482 
483 void ping_err(struct sk_buff *skb, int offset, u32 info)
484 {
485         int family;
486         struct icmphdr *icmph;
487         struct inet_sock *inet_sock;
488         int type;
489         int code;
490         struct net *net = dev_net(skb->dev);
491         struct sock *sk;
492         int harderr;
493         int err;
494 
495         if (skb->protocol == htons(ETH_P_IP)) {
496                 family = AF_INET;
497                 type = icmp_hdr(skb)->type;
498                 code = icmp_hdr(skb)->code;
499                 icmph = (struct icmphdr *)(skb->data + offset);
500         } else if (skb->protocol == htons(ETH_P_IPV6)) {
501                 family = AF_INET6;
502                 type = icmp6_hdr(skb)->icmp6_type;
503                 code = icmp6_hdr(skb)->icmp6_code;
504                 icmph = (struct icmphdr *) (skb->data + offset);
505         } else {
506                 BUG();
507         }
508 
509         /* We assume the packet has already been checked by icmp_unreach */
510 
511         if (!ping_supported(family, icmph->type, icmph->code))
512                 return;
513 
514         pr_debug("ping_err(proto=0x%x,type=%d,code=%d,id=%04x,seq=%04x)\n",
515                  skb->protocol, type, code, ntohs(icmph->un.echo.id),
516                  ntohs(icmph->un.echo.sequence));
517 
518         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
519         if (!sk) {
520                 pr_debug("no socket, dropping\n");
521                 return; /* No socket for error */
522         }
523         pr_debug("err on socket %p\n", sk);
524 
525         err = 0;
526         harderr = 0;
527         inet_sock = inet_sk(sk);
528 
529         if (skb->protocol == htons(ETH_P_IP)) {
530                 switch (type) {
531                 default:
532                 case ICMP_TIME_EXCEEDED:
533                         err = EHOSTUNREACH;
534                         break;
535                 case ICMP_SOURCE_QUENCH:
536                         /* This is not a real error but ping wants to see it.
537                          * Report it with some fake errno.
538                          */
539                         err = EREMOTEIO;
540                         break;
541                 case ICMP_PARAMETERPROB:
542                         err = EPROTO;
543                         harderr = 1;
544                         break;
545                 case ICMP_DEST_UNREACH:
546                         if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
547                                 ipv4_sk_update_pmtu(skb, sk, info);
548                                 if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
549                                         err = EMSGSIZE;
550                                         harderr = 1;
551                                         break;
552                                 }
553                                 goto out;
554                         }
555                         err = EHOSTUNREACH;
556                         if (code <= NR_ICMP_UNREACH) {
557                                 harderr = icmp_err_convert[code].fatal;
558                                 err = icmp_err_convert[code].errno;
559                         }
560                         break;
561                 case ICMP_REDIRECT:
562                         /* See ICMP_SOURCE_QUENCH */
563                         ipv4_sk_redirect(skb, sk);
564                         err = EREMOTEIO;
565                         break;
566                 }
567 #if IS_ENABLED(CONFIG_IPV6)
568         } else if (skb->protocol == htons(ETH_P_IPV6)) {
569                 harderr = pingv6_ops.icmpv6_err_convert(type, code, &err);
570 #endif
571         }
572 
573         /*
574          *      RFC1122: OK.  Passes ICMP errors back to application, as per
575          *      4.1.3.3.
576          */
577         if ((family == AF_INET && !inet_sock->recverr) ||
578             (family == AF_INET6 && !inet6_sk(sk)->recverr)) {
579                 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
580                         goto out;
581         } else {
582                 if (family == AF_INET) {
583                         ip_icmp_error(sk, skb, err, 0 /* no remote port */,
584                                       info, (u8 *)icmph);
585 #if IS_ENABLED(CONFIG_IPV6)
586                 } else if (family == AF_INET6) {
587                         pingv6_ops.ipv6_icmp_error(sk, skb, err, 0,
588                                                    info, (u8 *)icmph);
589 #endif
590                 }
591         }
592         sk->sk_err = err;
593         sk->sk_error_report(sk);
594 out:
595         sock_put(sk);
596 }
597 EXPORT_SYMBOL_GPL(ping_err);
598 
599 /*
600  *      Copy and checksum an ICMP Echo packet from user space into a buffer
601  *      starting from the payload.
602  */
603 
604 int ping_getfrag(void *from, char *to,
605                  int offset, int fraglen, int odd, struct sk_buff *skb)
606 {
607         struct pingfakehdr *pfh = (struct pingfakehdr *)from;
608 
609         if (offset == 0) {
610                 fraglen -= sizeof(struct icmphdr);
611                 if (fraglen < 0)
612                         BUG();
613                 if (!csum_and_copy_from_iter_full(to + sizeof(struct icmphdr),
614                             fraglen, &pfh->wcheck,
615                             &pfh->msg->msg_iter))
616                         return -EFAULT;
617         } else if (offset < sizeof(struct icmphdr)) {
618                         BUG();
619         } else {
620                 if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
621                                             &pfh->msg->msg_iter))
622                         return -EFAULT;
623         }
624 
625 #if IS_ENABLED(CONFIG_IPV6)
626         /* For IPv6, checksum each skb as we go along, as expected by
627          * icmpv6_push_pending_frames. For IPv4, accumulate the checksum in
628          * wcheck, it will be finalized in ping_v4_push_pending_frames.
629          */
630         if (pfh->family == AF_INET6) {
631                 skb->csum = pfh->wcheck;
632                 skb->ip_summed = CHECKSUM_NONE;
633                 pfh->wcheck = 0;
634         }
635 #endif
636 
637         return 0;
638 }
639 EXPORT_SYMBOL_GPL(ping_getfrag);
640 
641 static int ping_v4_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh,
642                                        struct flowi4 *fl4)
643 {
644         struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
645 
646         if (!skb)
647                 return 0;
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 
656 int 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         /* Must have at least a full ICMP header. */
664         if (len < icmph_len)
665                 return -EINVAL;
666 
667         /*
668          *      Check the flags.
669          */
670 
671         /* Mirror BSD error message compatibility */
672         if (msg->msg_flags & MSG_OOB)
673                 return -EOPNOTSUPP;
674 
675         /*
676          *      Fetch the ICMP header provided by the userland.
677          *      iovec is modified! The ICMP header is consumed.
678          */
679         if (memcpy_from_msg(user_icmph, msg, icmph_len))
680                 return -EFAULT;
681 
682         if (family == AF_INET) {
683                 type = ((struct icmphdr *) user_icmph)->type;
684                 code = ((struct icmphdr *) user_icmph)->code;
685 #if IS_ENABLED(CONFIG_IPV6)
686         } else if (family == AF_INET6) {
687                 type = ((struct icmp6hdr *) user_icmph)->icmp6_type;
688                 code = ((struct icmp6hdr *) user_icmph)->icmp6_code;
689 #endif
690         } else {
691                 BUG();
692         }
693 
694         if (!ping_supported(family, type, code))
695                 return -EINVAL;
696 
697         return 0;
698 }
699 EXPORT_SYMBOL_GPL(ping_common_sendmsg);
700 
701 static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
702 {
703         struct net *net = sock_net(sk);
704         struct flowi4 fl4;
705         struct inet_sock *inet = inet_sk(sk);
706         struct ipcm_cookie ipc;
707         struct icmphdr user_icmph;
708         struct pingfakehdr pfh;
709         struct rtable *rt = NULL;
710         struct ip_options_data opt_copy;
711         int free = 0;
712         __be32 saddr, daddr, faddr;
713         u8  tos;
714         int err;
715 
716         pr_debug("ping_v4_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
717 
718         err = ping_common_sendmsg(AF_INET, msg, len, &user_icmph,
719                                   sizeof(user_icmph));
720         if (err)
721                 return err;
722 
723         /*
724          *      Get and verify the address.
725          */
726 
727         if (msg->msg_name) {
728                 DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
729                 if (msg->msg_namelen < sizeof(*usin))
730                         return -EINVAL;
731                 if (usin->sin_family != AF_INET)
732                         return -EAFNOSUPPORT;
733                 daddr = usin->sin_addr.s_addr;
734                 /* no remote port */
735         } else {
736                 if (sk->sk_state != TCP_ESTABLISHED)
737                         return -EDESTADDRREQ;
738                 daddr = inet->inet_daddr;
739                 /* no remote port */
740         }
741 
742         ipc.sockc.tsflags = sk->sk_tsflags;
743         ipc.addr = inet->inet_saddr;
744         ipc.opt = NULL;
745         ipc.oif = sk->sk_bound_dev_if;
746         ipc.tx_flags = 0;
747         ipc.ttl = 0;
748         ipc.tos = -1;
749 
750         if (msg->msg_controllen) {
751                 err = ip_cmsg_send(sk, msg, &ipc, false);
752                 if (unlikely(err)) {
753                         kfree(ipc.opt);
754                         return err;
755                 }
756                 if (ipc.opt)
757                         free = 1;
758         }
759         if (!ipc.opt) {
760                 struct ip_options_rcu *inet_opt;
761 
762                 rcu_read_lock();
763                 inet_opt = rcu_dereference(inet->inet_opt);
764                 if (inet_opt) {
765                         memcpy(&opt_copy, inet_opt,
766                                sizeof(*inet_opt) + inet_opt->opt.optlen);
767                         ipc.opt = &opt_copy.opt;
768                 }
769                 rcu_read_unlock();
770         }
771 
772         sock_tx_timestamp(sk, ipc.sockc.tsflags, &ipc.tx_flags);
773 
774         saddr = ipc.addr;
775         ipc.addr = faddr = daddr;
776 
777         if (ipc.opt && ipc.opt->opt.srr) {
778                 if (!daddr)
779                         return -EINVAL;
780                 faddr = ipc.opt->opt.faddr;
781         }
782         tos = get_rttos(&ipc, inet);
783         if (sock_flag(sk, SOCK_LOCALROUTE) ||
784             (msg->msg_flags & MSG_DONTROUTE) ||
785             (ipc.opt && ipc.opt->opt.is_strictroute)) {
786                 tos |= RTO_ONLINK;
787         }
788 
789         if (ipv4_is_multicast(daddr)) {
790                 if (!ipc.oif)
791                         ipc.oif = inet->mc_index;
792                 if (!saddr)
793                         saddr = inet->mc_addr;
794         } else if (!ipc.oif)
795                 ipc.oif = inet->uc_index;
796 
797         flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
798                            RT_SCOPE_UNIVERSE, sk->sk_protocol,
799                            inet_sk_flowi_flags(sk), faddr, saddr, 0, 0,
800                            sk->sk_uid);
801 
802         security_sk_classify_flow(sk, flowi4_to_flowi(&fl4));
803         rt = ip_route_output_flow(net, &fl4, sk);
804         if (IS_ERR(rt)) {
805                 err = PTR_ERR(rt);
806                 rt = NULL;
807                 if (err == -ENETUNREACH)
808                         IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
809                 goto out;
810         }
811 
812         err = -EACCES;
813         if ((rt->rt_flags & RTCF_BROADCAST) &&
814             !sock_flag(sk, SOCK_BROADCAST))
815                 goto out;
816 
817         if (msg->msg_flags & MSG_CONFIRM)
818                 goto do_confirm;
819 back_from_confirm:
820 
821         if (!ipc.addr)
822                 ipc.addr = fl4.daddr;
823 
824         lock_sock(sk);
825 
826         pfh.icmph.type = user_icmph.type; /* already checked */
827         pfh.icmph.code = user_icmph.code; /* ditto */
828         pfh.icmph.checksum = 0;
829         pfh.icmph.un.echo.id = inet->inet_sport;
830         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
831         pfh.msg = msg;
832         pfh.wcheck = 0;
833         pfh.family = AF_INET;
834 
835         err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
836                         0, &ipc, &rt, msg->msg_flags);
837         if (err)
838                 ip_flush_pending_frames(sk);
839         else
840                 err = ping_v4_push_pending_frames(sk, &pfh, &fl4);
841         release_sock(sk);
842 
843 out:
844         ip_rt_put(rt);
845         if (free)
846                 kfree(ipc.opt);
847         if (!err) {
848                 icmp_out_count(sock_net(sk), user_icmph.type);
849                 return len;
850         }
851         return err;
852 
853 do_confirm:
854         if (msg->msg_flags & MSG_PROBE)
855                 dst_confirm_neigh(&rt->dst, &fl4.daddr);
856         if (!(msg->msg_flags & MSG_PROBE) || len)
857                 goto back_from_confirm;
858         err = 0;
859         goto out;
860 }
861 
862 int ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
863                  int flags, int *addr_len)
864 {
865         struct inet_sock *isk = inet_sk(sk);
866         int family = sk->sk_family;
867         struct sk_buff *skb;
868         int copied, err;
869 
870         pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
871 
872         err = -EOPNOTSUPP;
873         if (flags & MSG_OOB)
874                 goto out;
875 
876         if (flags & MSG_ERRQUEUE)
877                 return inet_recv_error(sk, msg, len, addr_len);
878 
879         skb = skb_recv_datagram(sk, flags, noblock, &err);
880         if (!skb)
881                 goto out;
882 
883         copied = skb->len;
884         if (copied > len) {
885                 msg->msg_flags |= MSG_TRUNC;
886                 copied = len;
887         }
888 
889         /* Don't bother checking the checksum */
890         err = skb_copy_datagram_msg(skb, 0, msg, copied);
891         if (err)
892                 goto done;
893 
894         sock_recv_timestamp(msg, sk, skb);
895 
896         /* Copy the address and add cmsg data. */
897         if (family == AF_INET) {
898                 DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
899 
900                 if (sin) {
901                         sin->sin_family = AF_INET;
902                         sin->sin_port = 0 /* skb->h.uh->source */;
903                         sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
904                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
905                         *addr_len = sizeof(*sin);
906                 }
907 
908                 if (isk->cmsg_flags)
909                         ip_cmsg_recv(msg, skb);
910 
911 #if IS_ENABLED(CONFIG_IPV6)
912         } else if (family == AF_INET6) {
913                 struct ipv6_pinfo *np = inet6_sk(sk);
914                 struct ipv6hdr *ip6 = ipv6_hdr(skb);
915                 DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
916 
917                 if (sin6) {
918                         sin6->sin6_family = AF_INET6;
919                         sin6->sin6_port = 0;
920                         sin6->sin6_addr = ip6->saddr;
921                         sin6->sin6_flowinfo = 0;
922                         if (np->sndflow)
923                                 sin6->sin6_flowinfo = ip6_flowinfo(ip6);
924                         sin6->sin6_scope_id =
925                                 ipv6_iface_scope_id(&sin6->sin6_addr,
926                                                     inet6_iif(skb));
927                         *addr_len = sizeof(*sin6);
928                 }
929 
930                 if (inet6_sk(sk)->rxopt.all)
931                         pingv6_ops.ip6_datagram_recv_common_ctl(sk, msg, skb);
932                 if (skb->protocol == htons(ETH_P_IPV6) &&
933                     inet6_sk(sk)->rxopt.all)
934                         pingv6_ops.ip6_datagram_recv_specific_ctl(sk, msg, skb);
935                 else if (skb->protocol == htons(ETH_P_IP) && isk->cmsg_flags)
936                         ip_cmsg_recv(msg, skb);
937 #endif
938         } else {
939                 BUG();
940         }
941 
942         err = copied;
943 
944 done:
945         skb_free_datagram(sk, skb);
946 out:
947         pr_debug("ping_recvmsg -> %d\n", err);
948         return err;
949 }
950 EXPORT_SYMBOL_GPL(ping_recvmsg);
951 
952 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
953 {
954         pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
955                  inet_sk(sk), inet_sk(sk)->inet_num, skb);
956         if (sock_queue_rcv_skb(sk, skb) < 0) {
957                 kfree_skb(skb);
958                 pr_debug("ping_queue_rcv_skb -> failed\n");
959                 return -1;
960         }
961         return 0;
962 }
963 EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
964 
965 
966 /*
967  *      All we need to do is get the socket.
968  */
969 
970 bool ping_rcv(struct sk_buff *skb)
971 {
972         struct sock *sk;
973         struct net *net = dev_net(skb->dev);
974         struct icmphdr *icmph = icmp_hdr(skb);
975 
976         /* We assume the packet has already been checked by icmp_rcv */
977 
978         pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
979                  skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
980 
981         /* Push ICMP header back */
982         skb_push(skb, skb->data - (u8 *)icmph);
983 
984         sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id));
985         if (sk) {
986                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
987 
988                 pr_debug("rcv on socket %p\n", sk);
989                 if (skb2)
990                         ping_queue_rcv_skb(sk, skb2);
991                 sock_put(sk);
992                 return true;
993         }
994         pr_debug("no socket, dropping\n");
995 
996         return false;
997 }
998 EXPORT_SYMBOL_GPL(ping_rcv);
999 
1000 struct proto ping_prot = {
1001         .name =         "PING",
1002         .owner =        THIS_MODULE,
1003         .init =         ping_init_sock,
1004         .close =        ping_close,
1005         .connect =      ip4_datagram_connect,
1006         .disconnect =   __udp_disconnect,
1007         .setsockopt =   ip_setsockopt,
1008         .getsockopt =   ip_getsockopt,
1009         .sendmsg =      ping_v4_sendmsg,
1010         .recvmsg =      ping_recvmsg,
1011         .bind =         ping_bind,
1012         .backlog_rcv =  ping_queue_rcv_skb,
1013         .release_cb =   ip4_datagram_release_cb,
1014         .hash =         ping_hash,
1015         .unhash =       ping_unhash,
1016         .get_port =     ping_get_port,
1017         .obj_size =     sizeof(struct inet_sock),
1018 };
1019 EXPORT_SYMBOL(ping_prot);
1020 
1021 #ifdef CONFIG_PROC_FS
1022 
1023 static struct sock *ping_get_first(struct seq_file *seq, int start)
1024 {
1025         struct sock *sk;
1026         struct ping_iter_state *state = seq->private;
1027         struct net *net = seq_file_net(seq);
1028 
1029         for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
1030              ++state->bucket) {
1031                 struct hlist_nulls_node *node;
1032                 struct hlist_nulls_head *hslot;
1033 
1034                 hslot = &ping_table.hash[state->bucket];
1035 
1036                 if (hlist_nulls_empty(hslot))
1037                         continue;
1038 
1039                 sk_nulls_for_each(sk, node, hslot) {
1040                         if (net_eq(sock_net(sk), net) &&
1041                             sk->sk_family == state->family)
1042                                 goto found;
1043                 }
1044         }
1045         sk = NULL;
1046 found:
1047         return sk;
1048 }
1049 
1050 static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
1051 {
1052         struct ping_iter_state *state = seq->private;
1053         struct net *net = seq_file_net(seq);
1054 
1055         do {
1056                 sk = sk_nulls_next(sk);
1057         } while (sk && (!net_eq(sock_net(sk), net)));
1058 
1059         if (!sk)
1060                 return ping_get_first(seq, state->bucket + 1);
1061         return sk;
1062 }
1063 
1064 static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
1065 {
1066         struct sock *sk = ping_get_first(seq, 0);
1067 
1068         if (sk)
1069                 while (pos && (sk = ping_get_next(seq, sk)) != NULL)
1070                         --pos;
1071         return pos ? NULL : sk;
1072 }
1073 
1074 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family)
1075         __acquires(ping_table.lock)
1076 {
1077         struct ping_iter_state *state = seq->private;
1078         state->bucket = 0;
1079         state->family = family;
1080 
1081         read_lock_bh(&ping_table.lock);
1082 
1083         return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
1084 }
1085 EXPORT_SYMBOL_GPL(ping_seq_start);
1086 
1087 static void *ping_v4_seq_start(struct seq_file *seq, loff_t *pos)
1088 {
1089         return ping_seq_start(seq, pos, AF_INET);
1090 }
1091 
1092 void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1093 {
1094         struct sock *sk;
1095 
1096         if (v == SEQ_START_TOKEN)
1097                 sk = ping_get_idx(seq, 0);
1098         else
1099                 sk = ping_get_next(seq, v);
1100 
1101         ++*pos;
1102         return sk;
1103 }
1104 EXPORT_SYMBOL_GPL(ping_seq_next);
1105 
1106 void ping_seq_stop(struct seq_file *seq, void *v)
1107         __releases(ping_table.lock)
1108 {
1109         read_unlock_bh(&ping_table.lock);
1110 }
1111 EXPORT_SYMBOL_GPL(ping_seq_stop);
1112 
1113 static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
1114                 int bucket)
1115 {
1116         struct inet_sock *inet = inet_sk(sp);
1117         __be32 dest = inet->inet_daddr;
1118         __be32 src = inet->inet_rcv_saddr;
1119         __u16 destp = ntohs(inet->inet_dport);
1120         __u16 srcp = ntohs(inet->inet_sport);
1121 
1122         seq_printf(f, "%5d: %08X:%04X %08X:%04X"
1123                 " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
1124                 bucket, src, srcp, dest, destp, sp->sk_state,
1125                 sk_wmem_alloc_get(sp),
1126                 sk_rmem_alloc_get(sp),
1127                 0, 0L, 0,
1128                 from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
1129                 0, sock_i_ino(sp),
1130                 refcount_read(&sp->sk_refcnt), sp,
1131                 atomic_read(&sp->sk_drops));
1132 }
1133 
1134 static int ping_v4_seq_show(struct seq_file *seq, void *v)
1135 {
1136         seq_setwidth(seq, 127);
1137         if (v == SEQ_START_TOKEN)
1138                 seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
1139                            "rx_queue tr tm->when retrnsmt   uid  timeout "
1140                            "inode ref pointer drops");
1141         else {
1142                 struct ping_iter_state *state = seq->private;
1143 
1144                 ping_v4_format_sock(v, seq, state->bucket);
1145         }
1146         seq_pad(seq, '\n');
1147         return 0;
1148 }
1149 
1150 static int ping_seq_open(struct inode *inode, struct file *file)
1151 {
1152         struct ping_seq_afinfo *afinfo = PDE_DATA(inode);
1153         return seq_open_net(inode, file, &afinfo->seq_ops,
1154                            sizeof(struct ping_iter_state));
1155 }
1156 
1157 const struct file_operations ping_seq_fops = {
1158         .open           = ping_seq_open,
1159         .read           = seq_read,
1160         .llseek         = seq_lseek,
1161         .release        = seq_release_net,
1162 };
1163 EXPORT_SYMBOL_GPL(ping_seq_fops);
1164 
1165 static struct ping_seq_afinfo ping_v4_seq_afinfo = {
1166         .name           = "icmp",
1167         .family         = AF_INET,
1168         .seq_fops       = &ping_seq_fops,
1169         .seq_ops        = {
1170                 .start          = ping_v4_seq_start,
1171                 .show           = ping_v4_seq_show,
1172                 .next           = ping_seq_next,
1173                 .stop           = ping_seq_stop,
1174         },
1175 };
1176 
1177 int ping_proc_register(struct net *net, struct ping_seq_afinfo *afinfo)
1178 {
1179         struct proc_dir_entry *p;
1180         p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
1181                              afinfo->seq_fops, afinfo);
1182         if (!p)
1183                 return -ENOMEM;
1184         return 0;
1185 }
1186 EXPORT_SYMBOL_GPL(ping_proc_register);
1187 
1188 void ping_proc_unregister(struct net *net, struct ping_seq_afinfo *afinfo)
1189 {
1190         remove_proc_entry(afinfo->name, net->proc_net);
1191 }
1192 EXPORT_SYMBOL_GPL(ping_proc_unregister);
1193 
1194 static int __net_init ping_v4_proc_init_net(struct net *net)
1195 {
1196         return ping_proc_register(net, &ping_v4_seq_afinfo);
1197 }
1198 
1199 static void __net_exit ping_v4_proc_exit_net(struct net *net)
1200 {
1201         ping_proc_unregister(net, &ping_v4_seq_afinfo);
1202 }
1203 
1204 static struct pernet_operations ping_v4_net_ops = {
1205         .init = ping_v4_proc_init_net,
1206         .exit = ping_v4_proc_exit_net,
1207 };
1208 
1209 int __init ping_proc_init(void)
1210 {
1211         return register_pernet_subsys(&ping_v4_net_ops);
1212 }
1213 
1214 void ping_proc_exit(void)
1215 {
1216         unregister_pernet_subsys(&ping_v4_net_ops);
1217 }
1218 
1219 #endif
1220 
1221 void __init ping_init(void)
1222 {
1223         int i;
1224 
1225         for (i = 0; i < PING_HTABLE_SIZE; i++)
1226                 INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
1227         rwlock_init(&ping_table.lock);
1228 }
1229 

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