xref: /kernel/linux/linux-5.10/net/core/sock_diag.c (revision 8c2ecf20) 
1/* License: GPL */
2
3#include <linux/mutex.h>
4#include <linux/socket.h>
5#include <linux/skbuff.h>
6#include <net/netlink.h>
7#include <net/net_namespace.h>
8#include <linux/module.h>
9#include <net/sock.h>
10#include <linux/kernel.h>
11#include <linux/tcp.h>
12#include <linux/workqueue.h>
13#include <linux/nospec.h>
14#include <linux/cookie.h>
15#include <linux/inet_diag.h>
16#include <linux/sock_diag.h>
17
18static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
19static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
20static DEFINE_MUTEX(sock_diag_table_mutex);
21static struct workqueue_struct *broadcast_wq;
22
23DEFINE_COOKIE(sock_cookie);
24
25u64 __sock_gen_cookie(struct sock *sk)
26{
27	while (1) {
28		u64 res = atomic64_read(&sk->sk_cookie);
29
30		if (res)
31			return res;
32		res = gen_cookie_next(&sock_cookie);
33		atomic64_cmpxchg(&sk->sk_cookie, 0, res);
34	}
35}
36
37int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
38{
39	u64 res;
40
41	if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
42		return 0;
43
44	res = sock_gen_cookie(sk);
45	if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
46		return -ESTALE;
47
48	return 0;
49}
50EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
51
52void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
53{
54	u64 res = sock_gen_cookie(sk);
55
56	cookie[0] = (u32)res;
57	cookie[1] = (u32)(res >> 32);
58}
59EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
60
61int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
62{
63	u32 mem[SK_MEMINFO_VARS];
64
65	sk_get_meminfo(sk, mem);
66
67	return nla_put(skb, attrtype, sizeof(mem), &mem);
68}
69EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
70
71int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
72			     struct sk_buff *skb, int attrtype)
73{
74	struct sock_fprog_kern *fprog;
75	struct sk_filter *filter;
76	struct nlattr *attr;
77	unsigned int flen;
78	int err = 0;
79
80	if (!may_report_filterinfo) {
81		nla_reserve(skb, attrtype, 0);
82		return 0;
83	}
84
85	rcu_read_lock();
86	filter = rcu_dereference(sk->sk_filter);
87	if (!filter)
88		goto out;
89
90	fprog = filter->prog->orig_prog;
91	if (!fprog)
92		goto out;
93
94	flen = bpf_classic_proglen(fprog);
95
96	attr = nla_reserve(skb, attrtype, flen);
97	if (attr == NULL) {
98		err = -EMSGSIZE;
99		goto out;
100	}
101
102	memcpy(nla_data(attr), fprog->filter, flen);
103out:
104	rcu_read_unlock();
105	return err;
106}
107EXPORT_SYMBOL(sock_diag_put_filterinfo);
108
109struct broadcast_sk {
110	struct sock *sk;
111	struct work_struct work;
112};
113
114static size_t sock_diag_nlmsg_size(void)
115{
116	return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
117	       + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
118	       + nla_total_size_64bit(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
119}
120
121static void sock_diag_broadcast_destroy_work(struct work_struct *work)
122{
123	struct broadcast_sk *bsk =
124		container_of(work, struct broadcast_sk, work);
125	struct sock *sk = bsk->sk;
126	const struct sock_diag_handler *hndl;
127	struct sk_buff *skb;
128	const enum sknetlink_groups group = sock_diag_destroy_group(sk);
129	int err = -1;
130
131	WARN_ON(group == SKNLGRP_NONE);
132
133	skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
134	if (!skb)
135		goto out;
136
137	mutex_lock(&sock_diag_table_mutex);
138	hndl = sock_diag_handlers[sk->sk_family];
139	if (hndl && hndl->get_info)
140		err = hndl->get_info(skb, sk);
141	mutex_unlock(&sock_diag_table_mutex);
142
143	if (!err)
144		nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
145				GFP_KERNEL);
146	else
147		kfree_skb(skb);
148out:
149	sk_destruct(sk);
150	kfree(bsk);
151}
152
153void sock_diag_broadcast_destroy(struct sock *sk)
154{
155	/* Note, this function is often called from an interrupt context. */
156	struct broadcast_sk *bsk =
157		kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
158	if (!bsk)
159		return sk_destruct(sk);
160	bsk->sk = sk;
161	INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
162	queue_work(broadcast_wq, &bsk->work);
163}
164
165void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
166{
167	mutex_lock(&sock_diag_table_mutex);
168	inet_rcv_compat = fn;
169	mutex_unlock(&sock_diag_table_mutex);
170}
171EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
172
173void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
174{
175	mutex_lock(&sock_diag_table_mutex);
176	inet_rcv_compat = NULL;
177	mutex_unlock(&sock_diag_table_mutex);
178}
179EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
180
181int sock_diag_register(const struct sock_diag_handler *hndl)
182{
183	int err = 0;
184
185	if (hndl->family >= AF_MAX)
186		return -EINVAL;
187
188	mutex_lock(&sock_diag_table_mutex);
189	if (sock_diag_handlers[hndl->family])
190		err = -EBUSY;
191	else
192		sock_diag_handlers[hndl->family] = hndl;
193	mutex_unlock(&sock_diag_table_mutex);
194
195	return err;
196}
197EXPORT_SYMBOL_GPL(sock_diag_register);
198
199void sock_diag_unregister(const struct sock_diag_handler *hnld)
200{
201	int family = hnld->family;
202
203	if (family >= AF_MAX)
204		return;
205
206	mutex_lock(&sock_diag_table_mutex);
207	BUG_ON(sock_diag_handlers[family] != hnld);
208	sock_diag_handlers[family] = NULL;
209	mutex_unlock(&sock_diag_table_mutex);
210}
211EXPORT_SYMBOL_GPL(sock_diag_unregister);
212
213static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
214{
215	int err;
216	struct sock_diag_req *req = nlmsg_data(nlh);
217	const struct sock_diag_handler *hndl;
218
219	if (nlmsg_len(nlh) < sizeof(*req))
220		return -EINVAL;
221
222	if (req->sdiag_family >= AF_MAX)
223		return -EINVAL;
224	req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX);
225
226	if (sock_diag_handlers[req->sdiag_family] == NULL)
227		sock_load_diag_module(req->sdiag_family, 0);
228
229	mutex_lock(&sock_diag_table_mutex);
230	hndl = sock_diag_handlers[req->sdiag_family];
231	if (hndl == NULL)
232		err = -ENOENT;
233	else if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY)
234		err = hndl->dump(skb, nlh);
235	else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy)
236		err = hndl->destroy(skb, nlh);
237	else
238		err = -EOPNOTSUPP;
239	mutex_unlock(&sock_diag_table_mutex);
240
241	return err;
242}
243
244static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
245			     struct netlink_ext_ack *extack)
246{
247	int ret;
248
249	switch (nlh->nlmsg_type) {
250	case TCPDIAG_GETSOCK:
251	case DCCPDIAG_GETSOCK:
252		if (inet_rcv_compat == NULL)
253			sock_load_diag_module(AF_INET, 0);
254
255		mutex_lock(&sock_diag_table_mutex);
256		if (inet_rcv_compat != NULL)
257			ret = inet_rcv_compat(skb, nlh);
258		else
259			ret = -EOPNOTSUPP;
260		mutex_unlock(&sock_diag_table_mutex);
261
262		return ret;
263	case SOCK_DIAG_BY_FAMILY:
264	case SOCK_DESTROY:
265		return __sock_diag_cmd(skb, nlh);
266	default:
267		return -EINVAL;
268	}
269}
270
271static DEFINE_MUTEX(sock_diag_mutex);
272
273static void sock_diag_rcv(struct sk_buff *skb)
274{
275	mutex_lock(&sock_diag_mutex);
276	netlink_rcv_skb(skb, &sock_diag_rcv_msg);
277	mutex_unlock(&sock_diag_mutex);
278}
279
280static int sock_diag_bind(struct net *net, int group)
281{
282	switch (group) {
283	case SKNLGRP_INET_TCP_DESTROY:
284	case SKNLGRP_INET_UDP_DESTROY:
285		if (!sock_diag_handlers[AF_INET])
286			sock_load_diag_module(AF_INET, 0);
287		break;
288	case SKNLGRP_INET6_TCP_DESTROY:
289	case SKNLGRP_INET6_UDP_DESTROY:
290		if (!sock_diag_handlers[AF_INET6])
291			sock_load_diag_module(AF_INET6, 0);
292		break;
293	}
294	return 0;
295}
296
297int sock_diag_destroy(struct sock *sk, int err)
298{
299	if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
300		return -EPERM;
301
302	if (!sk->sk_prot->diag_destroy)
303		return -EOPNOTSUPP;
304
305	return sk->sk_prot->diag_destroy(sk, err);
306}
307EXPORT_SYMBOL_GPL(sock_diag_destroy);
308
309static int __net_init diag_net_init(struct net *net)
310{
311	struct netlink_kernel_cfg cfg = {
312		.groups	= SKNLGRP_MAX,
313		.input	= sock_diag_rcv,
314		.bind	= sock_diag_bind,
315		.flags	= NL_CFG_F_NONROOT_RECV,
316	};
317
318	net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
319	return net->diag_nlsk == NULL ? -ENOMEM : 0;
320}
321
322static void __net_exit diag_net_exit(struct net *net)
323{
324	netlink_kernel_release(net->diag_nlsk);
325	net->diag_nlsk = NULL;
326}
327
328static struct pernet_operations diag_net_ops = {
329	.init = diag_net_init,
330	.exit = diag_net_exit,
331};
332
333static int __init sock_diag_init(void)
334{
335	broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
336	BUG_ON(!broadcast_wq);
337	return register_pernet_subsys(&diag_net_ops);
338}
339device_initcall(sock_diag_init);
340