xref: /linux/net/ipv6/ping.c (revision ab52c59103002b49f2455371e4b9c56ba3ef1781)
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 */
27 static int dummy_ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
28 				 int *addr_len)
29 {
30 	return -EAFNOSUPPORT;
31 }
32 static void dummy_ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
33 				       struct sk_buff *skb)
34 {
35 }
36 static int dummy_icmpv6_err_convert(u8 type, u8 code, int *err)
37 {
38 	return -EAFNOSUPPORT;
39 }
40 static void dummy_ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
41 				  __be16 port, u32 info, u8 *payload) {}
42 static 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 
48 static int ping_v6_pre_connect(struct sock *sk, struct sockaddr *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 
62 static 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 	ipc6.sockc.tsflags = READ_ONCE(sk->sk_tsflags);
123 	ipc6.sockc.mark = READ_ONCE(sk->sk_mark);
124 
125 	fl6.flowi6_oif = oif;
126 
127 	if (msg->msg_controllen) {
128 		struct ipv6_txoptions opt = {};
129 
130 		opt.tot_len = sizeof(opt);
131 		ipc6.opt = &opt;
132 
133 		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6);
134 		if (err < 0)
135 			return err;
136 
137 		/* Changes to txoptions and flow info are not implemented, yet.
138 		 * Drop the options.
139 		 */
140 		ipc6.opt = NULL;
141 	}
142 
143 	fl6.flowi6_proto = IPPROTO_ICMPV6;
144 	fl6.saddr = np->saddr;
145 	fl6.daddr = *daddr;
146 	fl6.flowi6_mark = ipc6.sockc.mark;
147 	fl6.flowi6_uid = sk->sk_uid;
148 	fl6.fl6_icmp_type = user_icmph.icmp6_type;
149 	fl6.fl6_icmp_code = user_icmph.icmp6_code;
150 	security_sk_classify_flow(sk, flowi6_to_flowi_common(&fl6));
151 
152 	fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
153 
154 	dst = ip6_sk_dst_lookup_flow(sk, &fl6, daddr, false);
155 	if (IS_ERR(dst))
156 		return PTR_ERR(dst);
157 	rt = dst_rt6_info(dst);
158 
159 	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
160 		fl6.flowi6_oif = READ_ONCE(np->mcast_oif);
161 	else if (!fl6.flowi6_oif)
162 		fl6.flowi6_oif = READ_ONCE(np->ucast_oif);
163 
164 	pfh.icmph.type = user_icmph.icmp6_type;
165 	pfh.icmph.code = user_icmph.icmp6_code;
166 	pfh.icmph.checksum = 0;
167 	pfh.icmph.un.echo.id = inet->inet_sport;
168 	pfh.icmph.un.echo.sequence = user_icmph.icmp6_sequence;
169 	pfh.msg = msg;
170 	pfh.wcheck = 0;
171 	pfh.family = AF_INET6;
172 
173 	if (ipc6.hlimit < 0)
174 		ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
175 
176 	lock_sock(sk);
177 	err = ip6_append_data(sk, ping_getfrag, &pfh, len,
178 			      sizeof(struct icmp6hdr), &ipc6, &fl6, rt,
179 			      MSG_DONTWAIT);
180 
181 	if (err) {
182 		ICMP6_INC_STATS(sock_net(sk), rt->rt6i_idev,
183 				ICMP6_MIB_OUTERRORS);
184 		ip6_flush_pending_frames(sk);
185 	} else {
186 		icmpv6_push_pending_frames(sk, &fl6,
187 					   (struct icmp6hdr *)&pfh.icmph, len);
188 	}
189 	release_sock(sk);
190 
191 	dst_release(dst);
192 
193 	if (err)
194 		return err;
195 
196 	return len;
197 }
198 
199 struct proto pingv6_prot = {
200 	.name =		"PINGv6",
201 	.owner =	THIS_MODULE,
202 	.init =		ping_init_sock,
203 	.close =	ping_close,
204 	.pre_connect =	ping_v6_pre_connect,
205 	.connect =	ip6_datagram_connect_v6_only,
206 	.disconnect =	__udp_disconnect,
207 	.setsockopt =	ipv6_setsockopt,
208 	.getsockopt =	ipv6_getsockopt,
209 	.sendmsg =	ping_v6_sendmsg,
210 	.recvmsg =	ping_recvmsg,
211 	.bind =		ping_bind,
212 	.backlog_rcv =	ping_queue_rcv_skb,
213 	.hash =		ping_hash,
214 	.unhash =	ping_unhash,
215 	.get_port =	ping_get_port,
216 	.put_port =	ping_unhash,
217 	.obj_size =	sizeof(struct raw6_sock),
218 	.ipv6_pinfo_offset = offsetof(struct raw6_sock, inet6),
219 };
220 EXPORT_SYMBOL_GPL(pingv6_prot);
221 
222 static struct inet_protosw pingv6_protosw = {
223 	.type =      SOCK_DGRAM,
224 	.protocol =  IPPROTO_ICMPV6,
225 	.prot =      &pingv6_prot,
226 	.ops =       &inet6_sockraw_ops,
227 	.flags =     INET_PROTOSW_REUSE,
228 };
229 
230 #ifdef CONFIG_PROC_FS
231 static void *ping_v6_seq_start(struct seq_file *seq, loff_t *pos)
232 {
233 	return ping_seq_start(seq, pos, AF_INET6);
234 }
235 
236 static int ping_v6_seq_show(struct seq_file *seq, void *v)
237 {
238 	if (v == SEQ_START_TOKEN) {
239 		seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
240 	} else {
241 		int bucket = ((struct ping_iter_state *) seq->private)->bucket;
242 		struct inet_sock *inet = inet_sk((struct sock *)v);
243 		__u16 srcp = ntohs(inet->inet_sport);
244 		__u16 destp = ntohs(inet->inet_dport);
245 		ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
246 	}
247 	return 0;
248 }
249 
250 static const struct seq_operations ping_v6_seq_ops = {
251 	.start		= ping_v6_seq_start,
252 	.show		= ping_v6_seq_show,
253 	.next		= ping_seq_next,
254 	.stop		= ping_seq_stop,
255 };
256 
257 static int __net_init ping_v6_proc_init_net(struct net *net)
258 {
259 	if (!proc_create_net("icmp6", 0444, net->proc_net, &ping_v6_seq_ops,
260 			sizeof(struct ping_iter_state)))
261 		return -ENOMEM;
262 	return 0;
263 }
264 
265 static void __net_exit ping_v6_proc_exit_net(struct net *net)
266 {
267 	remove_proc_entry("icmp6", net->proc_net);
268 }
269 
270 static struct pernet_operations ping_v6_net_ops = {
271 	.init = ping_v6_proc_init_net,
272 	.exit = ping_v6_proc_exit_net,
273 };
274 #endif
275 
276 int __init pingv6_init(void)
277 {
278 #ifdef CONFIG_PROC_FS
279 	int ret = register_pernet_subsys(&ping_v6_net_ops);
280 	if (ret)
281 		return ret;
282 #endif
283 	pingv6_ops.ipv6_recv_error = ipv6_recv_error;
284 	pingv6_ops.ip6_datagram_recv_common_ctl = ip6_datagram_recv_common_ctl;
285 	pingv6_ops.ip6_datagram_recv_specific_ctl =
286 		ip6_datagram_recv_specific_ctl;
287 	pingv6_ops.icmpv6_err_convert = icmpv6_err_convert;
288 	pingv6_ops.ipv6_icmp_error = ipv6_icmp_error;
289 	pingv6_ops.ipv6_chk_addr = ipv6_chk_addr;
290 	return inet6_register_protosw(&pingv6_protosw);
291 }
292 
293 /* This never gets called because it's not possible to unload the ipv6 module,
294  * but just in case.
295  */
296 void pingv6_exit(void)
297 {
298 	pingv6_ops.ipv6_recv_error = dummy_ipv6_recv_error;
299 	pingv6_ops.ip6_datagram_recv_common_ctl = dummy_ip6_datagram_recv_ctl;
300 	pingv6_ops.ip6_datagram_recv_specific_ctl = dummy_ip6_datagram_recv_ctl;
301 	pingv6_ops.icmpv6_err_convert = dummy_icmpv6_err_convert;
302 	pingv6_ops.ipv6_icmp_error = dummy_ipv6_icmp_error;
303 	pingv6_ops.ipv6_chk_addr = dummy_ipv6_chk_addr;
304 #ifdef CONFIG_PROC_FS
305 	unregister_pernet_subsys(&ping_v6_net_ops);
306 #endif
307 	inet6_unregister_protosw(&pingv6_protosw);
308 }
309