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