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 __rcu *sock_diag_handlers[AF_MAX];
20
21 static const struct sock_diag_inet_compat __rcu *inet_rcv_compat;
22
23 static struct workqueue_struct *broadcast_wq;
24
25 DEFINE_COOKIE(sock_cookie);
26
27 u64 __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
42 int 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 }
55 EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
56
57 void 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 }
64 EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
65
66 int 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 }
74 EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
75
76 int 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);
108 out:
109 rcu_read_unlock();
110 return err;
111 }
112 EXPORT_SYMBOL(sock_diag_put_filterinfo);
113
114 struct broadcast_sk {
115 struct sock *sk;
116 struct work_struct work;
117 };
118
119 static 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
126 static 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
139 static void sock_diag_unlock_handler(const struct sock_diag_handler *handler)
140 {
141 module_put(handler->owner);
142 }
143
144 static 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);
171 out:
172 sk_destruct(sk);
173 kfree(bsk);
174 }
175
176 void 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
188 void sock_diag_register_inet_compat(const struct sock_diag_inet_compat *ptr)
189 {
190 xchg(&inet_rcv_compat, RCU_INITIALIZER(ptr));
191 }
192 EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
193
194 void sock_diag_unregister_inet_compat(const struct sock_diag_inet_compat *ptr)
195 {
196 const struct sock_diag_inet_compat *old;
197
198 old = unrcu_pointer(xchg(&inet_rcv_compat, NULL));
199 WARN_ON_ONCE(old != ptr);
200 }
201 EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
202
203 int sock_diag_register(const struct sock_diag_handler *hndl)
204 {
205 int family = hndl->family;
206
207 if (family >= AF_MAX)
208 return -EINVAL;
209
210 return !cmpxchg((const struct sock_diag_handler **)
211 &sock_diag_handlers[family],
212 NULL, hndl) ? 0 : -EBUSY;
213 }
214 EXPORT_SYMBOL_GPL(sock_diag_register);
215
216 void sock_diag_unregister(const struct sock_diag_handler *hndl)
217 {
218 int family = hndl->family;
219
220 if (family >= AF_MAX)
221 return;
222
223 xchg((const struct sock_diag_handler **)&sock_diag_handlers[family],
224 NULL);
225 }
226 EXPORT_SYMBOL_GPL(sock_diag_unregister);
227
228 static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
229 {
230 int err;
231 struct sock_diag_req *req = nlmsg_data(nlh);
232 const struct sock_diag_handler *hndl;
233
234 if (nlmsg_len(nlh) < sizeof(*req))
235 return -EINVAL;
236
237 if (req->sdiag_family >= AF_MAX)
238 return -EINVAL;
239 req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX);
240
241 if (!rcu_access_pointer(sock_diag_handlers[req->sdiag_family]))
242 sock_load_diag_module(req->sdiag_family, 0);
243
244 hndl = sock_diag_lock_handler(req->sdiag_family);
245 if (hndl == NULL)
246 return -ENOENT;
247
248 if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY)
249 err = hndl->dump(skb, nlh);
250 else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy)
251 err = hndl->destroy(skb, nlh);
252 else
253 err = -EOPNOTSUPP;
254 sock_diag_unlock_handler(hndl);
255
256 return err;
257 }
258
259 static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
260 struct netlink_ext_ack *extack)
261 {
262 const struct sock_diag_inet_compat *ptr;
263 int ret;
264
265 switch (nlh->nlmsg_type) {
266 case TCPDIAG_GETSOCK:
267 case DCCPDIAG_GETSOCK:
268
269 if (!rcu_access_pointer(inet_rcv_compat))
270 sock_load_diag_module(AF_INET, 0);
271
272 rcu_read_lock();
273 ptr = rcu_dereference(inet_rcv_compat);
274 if (ptr && !try_module_get(ptr->owner))
275 ptr = NULL;
276 rcu_read_unlock();
277
278 ret = -EOPNOTSUPP;
279 if (ptr) {
280 ret = ptr->fn(skb, nlh);
281 module_put(ptr->owner);
282 }
283
284 return ret;
285 case SOCK_DIAG_BY_FAMILY:
286 case SOCK_DESTROY:
287 return __sock_diag_cmd(skb, nlh);
288 default:
289 return -EINVAL;
290 }
291 }
292
293 static void sock_diag_rcv(struct sk_buff *skb)
294 {
295 netlink_rcv_skb(skb, &sock_diag_rcv_msg);
296 }
297
298 static int sock_diag_bind(struct net *net, int group)
299 {
300 switch (group) {
301 case SKNLGRP_INET_TCP_DESTROY:
302 case SKNLGRP_INET_UDP_DESTROY:
303 if (!rcu_access_pointer(sock_diag_handlers[AF_INET]))
304 sock_load_diag_module(AF_INET, 0);
305 break;
306 case SKNLGRP_INET6_TCP_DESTROY:
307 case SKNLGRP_INET6_UDP_DESTROY:
308 if (!rcu_access_pointer(sock_diag_handlers[AF_INET6]))
309 sock_load_diag_module(AF_INET6, 0);
310 break;
311 }
312 return 0;
313 }
314
315 int sock_diag_destroy(struct sock *sk, int err)
316 {
317 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
318 return -EPERM;
319
320 if (!sk->sk_prot->diag_destroy)
321 return -EOPNOTSUPP;
322
323 return sk->sk_prot->diag_destroy(sk, err);
324 }
325 EXPORT_SYMBOL_GPL(sock_diag_destroy);
326
327 static int __net_init diag_net_init(struct net *net)
328 {
329 struct netlink_kernel_cfg cfg = {
330 .groups = SKNLGRP_MAX,
331 .input = sock_diag_rcv,
332 .bind = sock_diag_bind,
333 .flags = NL_CFG_F_NONROOT_RECV,
334 };
335
336 net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
337 return net->diag_nlsk == NULL ? -ENOMEM : 0;
338 }
339
340 static void __net_exit diag_net_exit(struct net *net)
341 {
342 netlink_kernel_release(net->diag_nlsk);
343 net->diag_nlsk = NULL;
344 }
345
346 static struct pernet_operations diag_net_ops = {
347 .init = diag_net_init,
348 .exit = diag_net_exit,
349 };
350
351 static int __init sock_diag_init(void)
352 {
353 broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
354 BUG_ON(!broadcast_wq);
355 return register_pernet_subsys(&diag_net_ops);
356 }
357 device_initcall(sock_diag_init);
358
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