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