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
__sock_gen_cookie(struct sock * sk)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
sock_diag_check_cookie(struct sock * sk,const __u32 * cookie)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
sock_diag_save_cookie(struct sock * sk,__u32 * cookie)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
sock_diag_put_meminfo(struct sock * sk,struct sk_buff * skb,int attrtype)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
sock_diag_put_filterinfo(bool may_report_filterinfo,struct sock * sk,struct sk_buff * skb,int attrtype)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
sock_diag_nlmsg_size(void)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
sock_diag_broadcast_destroy_work(struct work_struct * work)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
sock_diag_broadcast_destroy(struct sock * sk)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
sock_diag_register_inet_compat(int (* fn)(struct sk_buff * skb,struct nlmsghdr * nlh))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
sock_diag_unregister_inet_compat(int (* fn)(struct sk_buff * skb,struct nlmsghdr * nlh))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
sock_diag_register(const struct sock_diag_handler * hndl)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 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
sock_diag_unregister(const struct sock_diag_handler * hnld)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 sock_diag_handlers[family] = NULL;
209 mutex_unlock(&sock_diag_table_mutex);
210 }
211 EXPORT_SYMBOL_GPL(sock_diag_unregister);
212
__sock_diag_cmd(struct sk_buff * skb,struct nlmsghdr * nlh)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 (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
sock_diag_rcv_msg(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)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
sock_diag_rcv(struct sk_buff * skb)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
sock_diag_bind(struct net * net,int group)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 (!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 (!sock_diag_handlers[AF_INET6])
291 sock_load_diag_module(AF_INET6, 0);
292 break;
293 }
294 return 0;
295 }
296
sock_diag_destroy(struct sock * sk,int err)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
diag_net_init(struct net * net)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
diag_net_exit(struct net * net)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
sock_diag_init(void)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);
340
