ping.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * INET		An implementation of the TCP/IP protocol suite for the LINUX
  4 *		operating system.  INET is implemented using the  BSD Socket
  5 *		interface as the means of communication with the user level.
  6 *
  7 *		"Ping" sockets
  8 *
  9 * Based on ipv4/ping.c code.
 10 *
 11 * Authors:	Lorenzo Colitti (IPv6 support)
 12 *		Vasiliy Kulikov / Openwall (IPv4 implementation, for Linux 2.6),
 13 *		Pavel Kankovsky (IPv4 implementation, for Linux 2.4.32)
 14 */
 15
 16#include <net/addrconf.h>
 17#include <net/ipv6.h>
 18#include <net/ip6_route.h>
 19#include <net/protocol.h>
 20#include <net/udp.h>
 21#include <net/transp_v6.h>
 22#include <linux/proc_fs.h>
 23#include <linux/bpf-cgroup.h>
 24#include <net/ping.h>
 25
 26/* Compatibility glue so we can support IPv6 when it's compiled as a module */
 27static int dummy_ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
 28				 int *addr_len)
 29{
 30	return -EAFNOSUPPORT;
 31}
 32static void dummy_ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
 33				       struct sk_buff *skb)
 34{
 35}
 36static int dummy_icmpv6_err_convert(u8 type, u8 code, int *err)
 37{
 38	return -EAFNOSUPPORT;
 39}
 40static void dummy_ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 41				  __be16 port, u32 info, u8 *payload) {}
 42static int dummy_ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
 43			       const struct net_device *dev, int strict)
 44{
 45	return 0;
 46}
 47
 48static int ping_v6_pre_connect(struct sock *sk, struct sockaddr_unsized *uaddr,
 49			       int addr_len)
 50{
 51	/* This check is replicated from __ip6_datagram_connect() and
 52	 * intended to prevent BPF program called below from accessing
 53	 * bytes that are out of the bound specified by user in addr_len.
 54	 */
 55
 56	if (addr_len < SIN6_LEN_RFC2133)
 57		return -EINVAL;
 58
 59	return BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr, &addr_len);
 60}
 61
 62static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 63{
 64	struct inet_sock *inet = inet_sk(sk);
 65	struct ipv6_pinfo *np = inet6_sk(sk);
 66	struct icmp6hdr user_icmph;
 67	int addr_type;
 68	struct in6_addr *daddr;
 69	int oif = 0;
 70	struct flowi6 fl6;
 71	int err;
 72	struct dst_entry *dst;
 73	struct rt6_info *rt;
 74	struct pingfakehdr pfh;
 75	struct ipcm6_cookie ipc6;
 76
 77	err = ping_common_sendmsg(AF_INET6, msg, len, &user_icmph,
 78				  sizeof(user_icmph));
 79	if (err)
 80		return err;
 81
 82	memset(&fl6, 0, sizeof(fl6));
 83
 84	if (msg->msg_name) {
 85		DECLARE_SOCKADDR(struct sockaddr_in6 *, u, msg->msg_name);
 86		if (msg->msg_namelen < sizeof(*u))
 87			return -EINVAL;
 88		if (u->sin6_family != AF_INET6) {
 89			return -EAFNOSUPPORT;
 90		}
 91		daddr = &(u->sin6_addr);
 92		if (inet6_test_bit(SNDFLOW, sk))
 93			fl6.flowlabel = u->sin6_flowinfo & IPV6_FLOWINFO_MASK;
 94		if (__ipv6_addr_needs_scope_id(ipv6_addr_type(daddr)))
 95			oif = u->sin6_scope_id;
 96	} else {
 97		if (sk->sk_state != TCP_ESTABLISHED)
 98			return -EDESTADDRREQ;
 99		daddr = &sk->sk_v6_daddr;
100		fl6.flowlabel = np->flow_label;
101	}
102
103	if (!oif)
104		oif = sk->sk_bound_dev_if;
105
106	if (!oif)
107		oif = np->sticky_pktinfo.ipi6_ifindex;
108
109	if (!oif && ipv6_addr_is_multicast(daddr))
110		oif = READ_ONCE(np->mcast_oif);
111	else if (!oif)
112		oif = READ_ONCE(np->ucast_oif);
113
114	addr_type = ipv6_addr_type(daddr);
115	if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
116	    (addr_type & IPV6_ADDR_MAPPED) ||
117	    (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if &&
118	     l3mdev_master_ifindex_by_index(sock_net(sk), oif) != sk->sk_bound_dev_if))
119		return -EINVAL;
120
121	ipcm6_init_sk(&ipc6, sk);
122
123	fl6.flowi6_oif = oif;
124
125	if (msg->msg_controllen) {
126		struct ipv6_txoptions opt = {};
127
128		opt.tot_len = sizeof(opt);
129		ipc6.opt = &opt;
130
131		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6);
132		if (err < 0)
133			return err;
134
135		/* Changes to txoptions and flow info are not implemented, yet.
136		 * Drop the options.
137		 */
138		ipc6.opt = NULL;
139	}
140
141	fl6.flowi6_proto = IPPROTO_ICMPV6;
142	fl6.saddr = np->saddr;
143	fl6.daddr = *daddr;
144	fl6.flowi6_mark = ipc6.sockc.mark;
145	fl6.flowi6_uid = sk_uid(sk);
146	fl6.fl6_icmp_type = user_icmph.icmp6_type;
147	fl6.fl6_icmp_code = user_icmph.icmp6_code;
148	security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6));
149
150	fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
151
152	dst = ip6_sk_dst_lookup_flow(sk, &fl6, daddr, false);
153	if (IS_ERR(dst))
154		return PTR_ERR(dst);
155	rt = dst_rt6_info(dst);
156
157	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
158		fl6.flowi6_oif = READ_ONCE(np->mcast_oif);
159	else if (!fl6.flowi6_oif)
160		fl6.flowi6_oif = READ_ONCE(np->ucast_oif);
161
162	pfh.icmph.type = user_icmph.icmp6_type;
163	pfh.icmph.code = user_icmph.icmp6_code;
164	pfh.icmph.checksum = 0;
165	pfh.icmph.un.echo.id = inet->inet_sport;
166	pfh.icmph.un.echo.sequence = user_icmph.icmp6_sequence;
167	pfh.msg = msg;
168	pfh.wcheck = 0;
169	pfh.family = AF_INET6;
170
171	if (ipc6.hlimit < 0)
172		ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
173
174	lock_sock(sk);
175	err = ip6_append_data(sk, ping_getfrag, &pfh, len,
176			      sizeof(struct icmp6hdr), &ipc6, &fl6, rt,
177			      MSG_DONTWAIT);
178
179	if (err) {
180		ICMP6_INC_STATS(sock_net(sk), rt->rt6i_idev,
181				ICMP6_MIB_OUTERRORS);
182		ip6_flush_pending_frames(sk);
183	} else {
184		icmpv6_push_pending_frames(sk, &fl6,
185					   (struct icmp6hdr *)&pfh.icmph, len);
186	}
187	release_sock(sk);
188
189	dst_release(dst);
190
191	if (err)
192		return err;
193
194	return len;
195}
196
197struct proto pingv6_prot = {
198	.name =		"PINGv6",
199	.owner =	THIS_MODULE,
200	.init =		ping_init_sock,
201	.close =	ping_close,
202	.pre_connect =	ping_v6_pre_connect,
203	.connect =	ip6_datagram_connect_v6_only,
204	.disconnect =	__udp_disconnect,
205	.setsockopt =	ipv6_setsockopt,
206	.getsockopt =	ipv6_getsockopt,
207	.sendmsg =	ping_v6_sendmsg,
208	.recvmsg =	ping_recvmsg,
209	.bind =		ping_bind,
210	.backlog_rcv =	ping_queue_rcv_skb,
211	.unhash =	ping_unhash,
212	.get_port =	ping_get_port,
213	.put_port =	ping_unhash,
214	.obj_size =	sizeof(struct raw6_sock),
215	.ipv6_pinfo_offset = offsetof(struct raw6_sock, inet6),
216};
217EXPORT_SYMBOL_GPL(pingv6_prot);
218
219static struct inet_protosw pingv6_protosw = {
220	.type =      SOCK_DGRAM,
221	.protocol =  IPPROTO_ICMPV6,
222	.prot =      &pingv6_prot,
223	.ops =       &inet6_sockraw_ops,
224	.flags =     INET_PROTOSW_REUSE,
225};
226
227#ifdef CONFIG_PROC_FS
228static void *ping_v6_seq_start(struct seq_file *seq, loff_t *pos)
229{
230	return ping_seq_start(seq, pos, AF_INET6);
231}
232
233static int ping_v6_seq_show(struct seq_file *seq, void *v)
234{
235	if (v == SEQ_START_TOKEN) {
236		seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
237	} else {
238		int bucket = ((struct ping_iter_state *) seq->private)->bucket;
239		struct inet_sock *inet = inet_sk((struct sock *)v);
240		__u16 srcp = ntohs(inet->inet_sport);
241		__u16 destp = ntohs(inet->inet_dport);
242		ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
243	}
244	return 0;
245}
246
247static const struct seq_operations ping_v6_seq_ops = {
248	.start		= ping_v6_seq_start,
249	.show		= ping_v6_seq_show,
250	.next		= ping_seq_next,
251	.stop		= ping_seq_stop,
252};
253
254static int __net_init ping_v6_proc_init_net(struct net *net)
255{
256	if (!proc_create_net("icmp6", 0444, net->proc_net, &ping_v6_seq_ops,
257			sizeof(struct ping_iter_state)))
258		return -ENOMEM;
259	return 0;
260}
261
262static void __net_exit ping_v6_proc_exit_net(struct net *net)
263{
264	remove_proc_entry("icmp6", net->proc_net);
265}
266
267static struct pernet_operations ping_v6_net_ops = {
268	.init = ping_v6_proc_init_net,
269	.exit = ping_v6_proc_exit_net,
270};
271#endif
272
273int __init pingv6_init(void)
274{
275#ifdef CONFIG_PROC_FS
276	int ret = register_pernet_subsys(&ping_v6_net_ops);
277	if (ret)
278		return ret;
279#endif
280	pingv6_ops.ipv6_recv_error = ipv6_recv_error;
281	pingv6_ops.ip6_datagram_recv_common_ctl = ip6_datagram_recv_common_ctl;
282	pingv6_ops.ip6_datagram_recv_specific_ctl =
283		ip6_datagram_recv_specific_ctl;
284	pingv6_ops.icmpv6_err_convert = icmpv6_err_convert;
285	pingv6_ops.ipv6_icmp_error = ipv6_icmp_error;
286	pingv6_ops.ipv6_chk_addr = ipv6_chk_addr;
287	return inet6_register_protosw(&pingv6_protosw);
288}
289
290/* This never gets called because it's not possible to unload the ipv6 module,
291 * but just in case.
292 */
293void pingv6_exit(void)
294{
295	pingv6_ops.ipv6_recv_error = dummy_ipv6_recv_error;
296	pingv6_ops.ip6_datagram_recv_common_ctl = dummy_ip6_datagram_recv_ctl;
297	pingv6_ops.ip6_datagram_recv_specific_ctl = dummy_ip6_datagram_recv_ctl;
298	pingv6_ops.icmpv6_err_convert = dummy_icmpv6_err_convert;
299	pingv6_ops.ipv6_icmp_error = dummy_ipv6_icmp_error;
300	pingv6_ops.ipv6_chk_addr = dummy_ipv6_chk_addr;
301#ifdef CONFIG_PROC_FS
302	unregister_pernet_subsys(&ping_v6_net_ops);
303#endif
304	inet6_unregister_protosw(&pingv6_protosw);
305}