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 const 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(v: &sk->sk_cookie);
30
31 if (!res) {
32 u64 new = gen_cookie_next(gc: &sock_cookie);
33
34 atomic64_cmpxchg(v: &sk->sk_cookie, old: res, new);
35
36 /* Another thread might have changed sk_cookie before us. */
37 res = atomic64_read(v: &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, meminfo: mem);
71
72 return nla_put(skb, attrtype, attrlen: sizeof(mem), data: &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, attrlen: 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, attrlen: flen);
102 if (attr == NULL) {
103 err = -EMSGSIZE;
104 goto out;
105 }
106
107 memcpy(to: nla_data(nla: attr), from: fprog->filter, len: 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(module: 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(module: 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(payload: sock_diag_nlmsg_size(), GFP_KERNEL);
157 if (!skb)
158 goto out;
159
160 hndl = sock_diag_lock_handler(family: sk->sk_family);
161 if (hndl) {
162 if (hndl->get_info)
163 err = hndl->get_info(skb, sk);
164 sock_diag_unlock_handler(handler: hndl);
165 }
166 if (!err)
167 nlmsg_multicast(sk: sock_net(sk)->diag_nlsk, skb, portid: 0, group,
168 GFP_KERNEL);
169 else
170 kfree_skb(skb);
171out:
172 sk_destruct(sk);
173 kfree(objp: 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(wq: broadcast_wq, work: &bsk->work);
186}
187
188void sock_diag_register_inet_compat(const struct sock_diag_inet_compat *ptr)
189{
190 xchg(&inet_rcv_compat, RCU_INITIALIZER(ptr));
191}
192EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
193
194void 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}
201EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
202
203int 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}
214EXPORT_SYMBOL_GPL(sock_diag_register);
215
216void 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}
226EXPORT_SYMBOL_GPL(sock_diag_unregister);
227
228static 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(family: req->sdiag_family, protocol: 0);
243
244 hndl = sock_diag_lock_handler(family: 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(handler: hndl);
255
256 return err;
257}
258
259static 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 if (!rcu_access_pointer(inet_rcv_compat))
268 sock_load_diag_module(AF_INET, protocol: 0);
269
270 rcu_read_lock();
271 ptr = rcu_dereference(inet_rcv_compat);
272 if (ptr && !try_module_get(module: ptr->owner))
273 ptr = NULL;
274 rcu_read_unlock();
275
276 ret = -EOPNOTSUPP;
277 if (ptr) {
278 ret = ptr->fn(skb, nlh);
279 module_put(module: ptr->owner);
280 }
281
282 return ret;
283 case SOCK_DIAG_BY_FAMILY:
284 case SOCK_DESTROY:
285 return __sock_diag_cmd(skb, nlh);
286 default:
287 return -EINVAL;
288 }
289}
290
291static void sock_diag_rcv(struct sk_buff *skb)
292{
293 netlink_rcv_skb(skb, cb: &sock_diag_rcv_msg);
294}
295
296static int sock_diag_bind(struct net *net, int group)
297{
298 switch (group) {
299 case SKNLGRP_INET_TCP_DESTROY:
300 case SKNLGRP_INET_UDP_DESTROY:
301 if (!rcu_access_pointer(sock_diag_handlers[AF_INET]))
302 sock_load_diag_module(AF_INET, protocol: 0);
303 break;
304 case SKNLGRP_INET6_TCP_DESTROY:
305 case SKNLGRP_INET6_UDP_DESTROY:
306 if (!rcu_access_pointer(sock_diag_handlers[AF_INET6]))
307 sock_load_diag_module(AF_INET6, protocol: 0);
308 break;
309 }
310 return 0;
311}
312
313int sock_diag_destroy(struct sock *sk, int err)
314{
315 if (!ns_capable(ns: sock_net(sk)->user_ns, CAP_NET_ADMIN))
316 return -EPERM;
317
318 if (!sk->sk_prot->diag_destroy)
319 return -EOPNOTSUPP;
320
321 return sk->sk_prot->diag_destroy(sk, err);
322}
323EXPORT_SYMBOL_GPL(sock_diag_destroy);
324
325static int __net_init diag_net_init(struct net *net)
326{
327 struct netlink_kernel_cfg cfg = {
328 .groups = SKNLGRP_MAX,
329 .input = sock_diag_rcv,
330 .bind = sock_diag_bind,
331 .flags = NL_CFG_F_NONROOT_RECV,
332 };
333
334 net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, cfg: &cfg);
335 return net->diag_nlsk == NULL ? -ENOMEM : 0;
336}
337
338static void __net_exit diag_net_exit(struct net *net)
339{
340 netlink_kernel_release(sk: net->diag_nlsk);
341 net->diag_nlsk = NULL;
342}
343
344static struct pernet_operations diag_net_ops = {
345 .init = diag_net_init,
346 .exit = diag_net_exit,
347};
348
349static int __init sock_diag_init(void)
350{
351 broadcast_wq = alloc_workqueue("sock_diag_events", WQ_PERCPU, 0);
352 BUG_ON(!broadcast_wq);
353 return register_pernet_subsys(&diag_net_ops);
354}
355device_initcall(sock_diag_init);
356