1/* License: GPL */
2
3#include <linux/filter.h>
4#include <linux/mutex.h>
5#include <linux/socket.h>
6#include <linux/skbuff.h>
7#include <net/netlink.h>
8#include <net/net_namespace.h>
9#include <linux/module.h>
10#include <net/sock.h>
11#include <linux/kernel.h>
12#include <linux/tcp.h>
13#include <linux/workqueue.h>
14#include <linux/nospec.h>
15#include <linux/cookie.h>
16#include <linux/inet_diag.h>
17#include <linux/sock_diag.h>
18
19static const struct sock_diag_handler __rcu *sock_diag_handlers[AF_MAX];
20
21static struct sock_diag_inet_compat __rcu *inet_rcv_compat;
22
23static struct workqueue_struct *broadcast_wq;
24
25DEFINE_COOKIE(sock_cookie);
26
27u64 __sock_gen_cookie(struct sock *sk)
28{
29	u64 res = atomic64_read(&sk->sk_cookie);
30
31	if (!res) {
32		u64 new = gen_cookie_next(&sock_cookie);
33
34		atomic64_cmpxchg(&sk->sk_cookie, res, new);
35
36		/* Another thread might have changed sk_cookie before us. */
37		res = atomic64_read(&sk->sk_cookie);
38	}
39	return res;
40}
41
42int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
43{
44	u64 res;
45
46	if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
47		return 0;
48
49	res = sock_gen_cookie(sk);
50	if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
51		return -ESTALE;
52
53	return 0;
54}
55EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
56
57void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
58{
59	u64 res = sock_gen_cookie(sk);
60
61	cookie[0] = (u32)res;
62	cookie[1] = (u32)(res >> 32);
63}
64EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
65
66int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
67{
68	u32 mem[SK_MEMINFO_VARS];
69
70	sk_get_meminfo(sk, mem);
71
72	return nla_put(skb, attrtype, sizeof(mem), &mem);
73}
74EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
75
76int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
77			     struct sk_buff *skb, int attrtype)
78{
79	struct sock_fprog_kern *fprog;
80	struct sk_filter *filter;
81	struct nlattr *attr;
82	unsigned int flen;
83	int err = 0;
84
85	if (!may_report_filterinfo) {
86		nla_reserve(skb, attrtype, 0);
87		return 0;
88	}
89
90	rcu_read_lock();
91	filter = rcu_dereference(sk->sk_filter);
92	if (!filter)
93		goto out;
94
95	fprog = filter->prog->orig_prog;
96	if (!fprog)
97		goto out;
98
99	flen = bpf_classic_proglen(fprog);
100
101	attr = nla_reserve(skb, attrtype, flen);
102	if (attr == NULL) {
103		err = -EMSGSIZE;
104		goto out;
105	}
106
107	memcpy(nla_data(attr), fprog->filter, flen);
108out:
109	rcu_read_unlock();
110	return err;
111}
112EXPORT_SYMBOL(sock_diag_put_filterinfo);
113
114struct broadcast_sk {
115	struct sock *sk;
116	struct work_struct work;
117};
118
119static size_t sock_diag_nlmsg_size(void)
120{
121	return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
122	       + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
123	       + nla_total_size_64bit(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
124}
125
126static const struct sock_diag_handler *sock_diag_lock_handler(int family)
127{
128	const struct sock_diag_handler *handler;
129
130	rcu_read_lock();
131	handler = rcu_dereference(sock_diag_handlers[family]);
132	if (handler && !try_module_get(handler->owner))
133		handler = NULL;
134	rcu_read_unlock();
135
136	return handler;
137}
138
139static void sock_diag_unlock_handler(const struct sock_diag_handler *handler)
140{
141	module_put(handler->owner);
142}
143
144static void sock_diag_broadcast_destroy_work(struct work_struct *work)
145{
146	struct broadcast_sk *bsk =
147		container_of(work, struct broadcast_sk, work);
148	struct sock *sk = bsk->sk;
149	const struct sock_diag_handler *hndl;
150	struct sk_buff *skb;
151	const enum sknetlink_groups group = sock_diag_destroy_group(sk);
152	int err = -1;
153
154	WARN_ON(group == SKNLGRP_NONE);
155
156	skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
157	if (!skb)
158		goto out;
159
160	hndl = sock_diag_lock_handler(sk->sk_family);
161	if (hndl) {
162		if (hndl->get_info)
163			err = hndl->get_info(skb, sk);
164		sock_diag_unlock_handler(hndl);
165	}
166	if (!err)
167		nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
168				GFP_KERNEL);
169	else
170		kfree_skb(skb);
171out:
172	sk_destruct(sk);
173	kfree(bsk);
174}
175
176void sock_diag_broadcast_destroy(struct sock *sk)
177{
178	/* Note, this function is often called from an interrupt context. */
179	struct broadcast_sk *bsk =
180		kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
181	if (!bsk)
182		return sk_destruct(sk);
183	bsk->sk = sk;
184	INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
185	queue_work(broadcast_wq, &bsk->work);
186}
187
188void sock_diag_register_inet_compat(const struct sock_diag_inet_compat *ptr)
189{
190	xchg((__force const struct sock_diag_inet_compat **)&inet_rcv_compat,
191	     ptr);
192}
193EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
194
195void sock_diag_unregister_inet_compat(const struct sock_diag_inet_compat *ptr)
196{
197	const struct sock_diag_inet_compat *old;
198
199	old = xchg((__force const struct sock_diag_inet_compat **)&inet_rcv_compat,
200		   NULL);
201	WARN_ON_ONCE(old != ptr);
202}
203EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
204
205int sock_diag_register(const struct sock_diag_handler *hndl)
206{
207	int family = hndl->family;
208
209	if (family >= AF_MAX)
210		return -EINVAL;
211
212	return !cmpxchg((const struct sock_diag_handler **)
213				&sock_diag_handlers[family],
214			NULL, hndl) ? 0 : -EBUSY;
215}
216EXPORT_SYMBOL_GPL(sock_diag_register);
217
218void sock_diag_unregister(const struct sock_diag_handler *hndl)
219{
220	int family = hndl->family;
221
222	if (family >= AF_MAX)
223		return;
224
225	xchg((const struct sock_diag_handler **)&sock_diag_handlers[family],
226	     NULL);
227}
228EXPORT_SYMBOL_GPL(sock_diag_unregister);
229
230static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
231{
232	int err;
233	struct sock_diag_req *req = nlmsg_data(nlh);
234	const struct sock_diag_handler *hndl;
235
236	if (nlmsg_len(nlh) < sizeof(*req))
237		return -EINVAL;
238
239	if (req->sdiag_family >= AF_MAX)
240		return -EINVAL;
241	req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX);
242
243	if (!rcu_access_pointer(sock_diag_handlers[req->sdiag_family]))
244		sock_load_diag_module(req->sdiag_family, 0);
245
246	hndl = sock_diag_lock_handler(req->sdiag_family);
247	if (hndl == NULL)
248		return -ENOENT;
249
250	if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY)
251		err = hndl->dump(skb, nlh);
252	else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy)
253		err = hndl->destroy(skb, nlh);
254	else
255		err = -EOPNOTSUPP;
256	sock_diag_unlock_handler(hndl);
257
258	return err;
259}
260
261static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
262			     struct netlink_ext_ack *extack)
263{
264	const struct sock_diag_inet_compat *ptr;
265	int ret;
266
267	switch (nlh->nlmsg_type) {
268	case TCPDIAG_GETSOCK:
269	case DCCPDIAG_GETSOCK:
270
271		if (!rcu_access_pointer(inet_rcv_compat))
272			sock_load_diag_module(AF_INET, 0);
273
274		rcu_read_lock();
275		ptr = rcu_dereference(inet_rcv_compat);
276		if (ptr && !try_module_get(ptr->owner))
277			ptr = NULL;
278		rcu_read_unlock();
279
280		ret = -EOPNOTSUPP;
281		if (ptr) {
282			ret = ptr->fn(skb, nlh);
283			module_put(ptr->owner);
284		}
285
286		return ret;
287	case SOCK_DIAG_BY_FAMILY:
288	case SOCK_DESTROY:
289		return __sock_diag_cmd(skb, nlh);
290	default:
291		return -EINVAL;
292	}
293}
294
295static void sock_diag_rcv(struct sk_buff *skb)
296{
297	netlink_rcv_skb(skb, &sock_diag_rcv_msg);
298}
299
300static int sock_diag_bind(struct net *net, int group)
301{
302	switch (group) {
303	case SKNLGRP_INET_TCP_DESTROY:
304	case SKNLGRP_INET_UDP_DESTROY:
305		if (!rcu_access_pointer(sock_diag_handlers[AF_INET]))
306			sock_load_diag_module(AF_INET, 0);
307		break;
308	case SKNLGRP_INET6_TCP_DESTROY:
309	case SKNLGRP_INET6_UDP_DESTROY:
310		if (!rcu_access_pointer(sock_diag_handlers[AF_INET6]))
311			sock_load_diag_module(AF_INET6, 0);
312		break;
313	}
314	return 0;
315}
316
317int sock_diag_destroy(struct sock *sk, int err)
318{
319	if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
320		return -EPERM;
321
322	if (!sk->sk_prot->diag_destroy)
323		return -EOPNOTSUPP;
324
325	return sk->sk_prot->diag_destroy(sk, err);
326}
327EXPORT_SYMBOL_GPL(sock_diag_destroy);
328
329static int __net_init diag_net_init(struct net *net)
330{
331	struct netlink_kernel_cfg cfg = {
332		.groups	= SKNLGRP_MAX,
333		.input	= sock_diag_rcv,
334		.bind	= sock_diag_bind,
335		.flags	= NL_CFG_F_NONROOT_RECV,
336	};
337
338	net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
339	return net->diag_nlsk == NULL ? -ENOMEM : 0;
340}
341
342static void __net_exit diag_net_exit(struct net *net)
343{
344	netlink_kernel_release(net->diag_nlsk);
345	net->diag_nlsk = NULL;
346}
347
348static struct pernet_operations diag_net_ops = {
349	.init = diag_net_init,
350	.exit = diag_net_exit,
351};
352
353static int __init sock_diag_init(void)
354{
355	broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
356	BUG_ON(!broadcast_wq);
357	return register_pernet_subsys(&diag_net_ops);
358}
359device_initcall(sock_diag_init);
360