GNU Linux-libre 5.10.219-gnu1
[releases.git] / net / core / sock_diag.c
1 /* License: GPL */
2
3 #include <linux/mutex.h>
4 #include <linux/socket.h>
5 #include <linux/skbuff.h>
6 #include <net/netlink.h>
7 #include <net/net_namespace.h>
8 #include <linux/module.h>
9 #include <net/sock.h>
10 #include <linux/kernel.h>
11 #include <linux/tcp.h>
12 #include <linux/workqueue.h>
13 #include <linux/nospec.h>
14 #include <linux/cookie.h>
15 #include <linux/inet_diag.h>
16 #include <linux/sock_diag.h>
17
18 static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
19 static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
20 static DEFINE_MUTEX(sock_diag_table_mutex);
21 static struct workqueue_struct *broadcast_wq;
22
23 DEFINE_COOKIE(sock_cookie);
24
25 u64 __sock_gen_cookie(struct sock *sk)
26 {
27         while (1) {
28                 u64 res = atomic64_read(&sk->sk_cookie);
29
30                 if (res)
31                         return res;
32                 res = gen_cookie_next(&sock_cookie);
33                 atomic64_cmpxchg(&sk->sk_cookie, 0, res);
34         }
35 }
36
37 int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
38 {
39         u64 res;
40
41         if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
42                 return 0;
43
44         res = sock_gen_cookie(sk);
45         if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
46                 return -ESTALE;
47
48         return 0;
49 }
50 EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
51
52 void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
53 {
54         u64 res = sock_gen_cookie(sk);
55
56         cookie[0] = (u32)res;
57         cookie[1] = (u32)(res >> 32);
58 }
59 EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
60
61 int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
62 {
63         u32 mem[SK_MEMINFO_VARS];
64
65         sk_get_meminfo(sk, mem);
66
67         return nla_put(skb, attrtype, sizeof(mem), &mem);
68 }
69 EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
70
71 int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
72                              struct sk_buff *skb, int attrtype)
73 {
74         struct sock_fprog_kern *fprog;
75         struct sk_filter *filter;
76         struct nlattr *attr;
77         unsigned int flen;
78         int err = 0;
79
80         if (!may_report_filterinfo) {
81                 nla_reserve(skb, attrtype, 0);
82                 return 0;
83         }
84
85         rcu_read_lock();
86         filter = rcu_dereference(sk->sk_filter);
87         if (!filter)
88                 goto out;
89
90         fprog = filter->prog->orig_prog;
91         if (!fprog)
92                 goto out;
93
94         flen = bpf_classic_proglen(fprog);
95
96         attr = nla_reserve(skb, attrtype, flen);
97         if (attr == NULL) {
98                 err = -EMSGSIZE;
99                 goto out;
100         }
101
102         memcpy(nla_data(attr), fprog->filter, flen);
103 out:
104         rcu_read_unlock();
105         return err;
106 }
107 EXPORT_SYMBOL(sock_diag_put_filterinfo);
108
109 struct broadcast_sk {
110         struct sock *sk;
111         struct work_struct work;
112 };
113
114 static size_t sock_diag_nlmsg_size(void)
115 {
116         return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
117                + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
118                + nla_total_size_64bit(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
119 }
120
121 static void sock_diag_broadcast_destroy_work(struct work_struct *work)
122 {
123         struct broadcast_sk *bsk =
124                 container_of(work, struct broadcast_sk, work);
125         struct sock *sk = bsk->sk;
126         const struct sock_diag_handler *hndl;
127         struct sk_buff *skb;
128         const enum sknetlink_groups group = sock_diag_destroy_group(sk);
129         int err = -1;
130
131         WARN_ON(group == SKNLGRP_NONE);
132
133         skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
134         if (!skb)
135                 goto out;
136
137         mutex_lock(&sock_diag_table_mutex);
138         hndl = sock_diag_handlers[sk->sk_family];
139         if (hndl && hndl->get_info)
140                 err = hndl->get_info(skb, sk);
141         mutex_unlock(&sock_diag_table_mutex);
142
143         if (!err)
144                 nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
145                                 GFP_KERNEL);
146         else
147                 kfree_skb(skb);
148 out:
149         sk_destruct(sk);
150         kfree(bsk);
151 }
152
153 void sock_diag_broadcast_destroy(struct sock *sk)
154 {
155         /* Note, this function is often called from an interrupt context. */
156         struct broadcast_sk *bsk =
157                 kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
158         if (!bsk)
159                 return sk_destruct(sk);
160         bsk->sk = sk;
161         INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
162         queue_work(broadcast_wq, &bsk->work);
163 }
164
165 void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
166 {
167         mutex_lock(&sock_diag_table_mutex);
168         inet_rcv_compat = fn;
169         mutex_unlock(&sock_diag_table_mutex);
170 }
171 EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
172
173 void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
174 {
175         mutex_lock(&sock_diag_table_mutex);
176         inet_rcv_compat = NULL;
177         mutex_unlock(&sock_diag_table_mutex);
178 }
179 EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
180
181 int sock_diag_register(const struct sock_diag_handler *hndl)
182 {
183         int err = 0;
184
185         if (hndl->family >= AF_MAX)
186                 return -EINVAL;
187
188         mutex_lock(&sock_diag_table_mutex);
189         if (sock_diag_handlers[hndl->family])
190                 err = -EBUSY;
191         else
192                 WRITE_ONCE(sock_diag_handlers[hndl->family], hndl);
193         mutex_unlock(&sock_diag_table_mutex);
194
195         return err;
196 }
197 EXPORT_SYMBOL_GPL(sock_diag_register);
198
199 void sock_diag_unregister(const struct sock_diag_handler *hnld)
200 {
201         int family = hnld->family;
202
203         if (family >= AF_MAX)
204                 return;
205
206         mutex_lock(&sock_diag_table_mutex);
207         BUG_ON(sock_diag_handlers[family] != hnld);
208         WRITE_ONCE(sock_diag_handlers[family], NULL);
209         mutex_unlock(&sock_diag_table_mutex);
210 }
211 EXPORT_SYMBOL_GPL(sock_diag_unregister);
212
213 static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
214 {
215         int err;
216         struct sock_diag_req *req = nlmsg_data(nlh);
217         const struct sock_diag_handler *hndl;
218
219         if (nlmsg_len(nlh) < sizeof(*req))
220                 return -EINVAL;
221
222         if (req->sdiag_family >= AF_MAX)
223                 return -EINVAL;
224         req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX);
225
226         if (READ_ONCE(sock_diag_handlers[req->sdiag_family]) == NULL)
227                 sock_load_diag_module(req->sdiag_family, 0);
228
229         mutex_lock(&sock_diag_table_mutex);
230         hndl = sock_diag_handlers[req->sdiag_family];
231         if (hndl == NULL)
232                 err = -ENOENT;
233         else if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY)
234                 err = hndl->dump(skb, nlh);
235         else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy)
236                 err = hndl->destroy(skb, nlh);
237         else
238                 err = -EOPNOTSUPP;
239         mutex_unlock(&sock_diag_table_mutex);
240
241         return err;
242 }
243
244 static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
245                              struct netlink_ext_ack *extack)
246 {
247         int ret;
248
249         switch (nlh->nlmsg_type) {
250         case TCPDIAG_GETSOCK:
251         case DCCPDIAG_GETSOCK:
252                 if (inet_rcv_compat == NULL)
253                         sock_load_diag_module(AF_INET, 0);
254
255                 mutex_lock(&sock_diag_table_mutex);
256                 if (inet_rcv_compat != NULL)
257                         ret = inet_rcv_compat(skb, nlh);
258                 else
259                         ret = -EOPNOTSUPP;
260                 mutex_unlock(&sock_diag_table_mutex);
261
262                 return ret;
263         case SOCK_DIAG_BY_FAMILY:
264         case SOCK_DESTROY:
265                 return __sock_diag_cmd(skb, nlh);
266         default:
267                 return -EINVAL;
268         }
269 }
270
271 static DEFINE_MUTEX(sock_diag_mutex);
272
273 static void sock_diag_rcv(struct sk_buff *skb)
274 {
275         mutex_lock(&sock_diag_mutex);
276         netlink_rcv_skb(skb, &sock_diag_rcv_msg);
277         mutex_unlock(&sock_diag_mutex);
278 }
279
280 static int sock_diag_bind(struct net *net, int group)
281 {
282         switch (group) {
283         case SKNLGRP_INET_TCP_DESTROY:
284         case SKNLGRP_INET_UDP_DESTROY:
285                 if (!READ_ONCE(sock_diag_handlers[AF_INET]))
286                         sock_load_diag_module(AF_INET, 0);
287                 break;
288         case SKNLGRP_INET6_TCP_DESTROY:
289         case SKNLGRP_INET6_UDP_DESTROY:
290                 if (!READ_ONCE(sock_diag_handlers[AF_INET6]))
291                         sock_load_diag_module(AF_INET6, 0);
292                 break;
293         }
294         return 0;
295 }
296
297 int sock_diag_destroy(struct sock *sk, int err)
298 {
299         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
300                 return -EPERM;
301
302         if (!sk->sk_prot->diag_destroy)
303                 return -EOPNOTSUPP;
304
305         return sk->sk_prot->diag_destroy(sk, err);
306 }
307 EXPORT_SYMBOL_GPL(sock_diag_destroy);
308
309 static int __net_init diag_net_init(struct net *net)
310 {
311         struct netlink_kernel_cfg cfg = {
312                 .groups = SKNLGRP_MAX,
313                 .input  = sock_diag_rcv,
314                 .bind   = sock_diag_bind,
315                 .flags  = NL_CFG_F_NONROOT_RECV,
316         };
317
318         net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
319         return net->diag_nlsk == NULL ? -ENOMEM : 0;
320 }
321
322 static void __net_exit diag_net_exit(struct net *net)
323 {
324         netlink_kernel_release(net->diag_nlsk);
325         net->diag_nlsk = NULL;
326 }
327
328 static struct pernet_operations diag_net_ops = {
329         .init = diag_net_init,
330         .exit = diag_net_exit,
331 };
332
333 static int __init sock_diag_init(void)
334 {
335         broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
336         BUG_ON(!broadcast_wq);
337         return register_pernet_subsys(&diag_net_ops);
338 }
339 device_initcall(sock_diag_init);