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