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 u64 res = atomic64_read(&sk->sk_cookie);
29
30 if (!res) {
31 u64 new = gen_cookie_next(&sock_cookie);
32
33 atomic64_cmpxchg(&sk->sk_cookie, res, new);
34
35 /* Another thread might have changed sk_cookie before us. */
36 res = atomic64_read(&sk->sk_cookie);
37 }
38 return res;
39 }
40
sock_diag_check_cookie(struct sock * sk,const __u32 * cookie)41 int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
42 {
43 u64 res;
44
45 if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
46 return 0;
47
48 res = sock_gen_cookie(sk);
49 if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
50 return -ESTALE;
51
52 return 0;
53 }
54 EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
55
sock_diag_save_cookie(struct sock * sk,__u32 * cookie)56 void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
57 {
58 u64 res = sock_gen_cookie(sk);
59
60 cookie[0] = (u32)res;
61 cookie[1] = (u32)(res >> 32);
62 }
63 EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
64
sock_diag_put_meminfo(struct sock * sk,struct sk_buff * skb,int attrtype)65 int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
66 {
67 u32 mem[SK_MEMINFO_VARS];
68
69 sk_get_meminfo(sk, mem);
70
71 return nla_put(skb, attrtype, sizeof(mem), &mem);
72 }
73 EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
74
sock_diag_put_filterinfo(bool may_report_filterinfo,struct sock * sk,struct sk_buff * skb,int attrtype)75 int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
76 struct sk_buff *skb, int attrtype)
77 {
78 struct sock_fprog_kern *fprog;
79 struct sk_filter *filter;
80 struct nlattr *attr;
81 unsigned int flen;
82 int err = 0;
83
84 if (!may_report_filterinfo) {
85 nla_reserve(skb, attrtype, 0);
86 return 0;
87 }
88
89 rcu_read_lock();
90 filter = rcu_dereference(sk->sk_filter);
91 if (!filter)
92 goto out;
93
94 fprog = filter->prog->orig_prog;
95 if (!fprog)
96 goto out;
97
98 flen = bpf_classic_proglen(fprog);
99
100 attr = nla_reserve(skb, attrtype, flen);
101 if (attr == NULL) {
102 err = -EMSGSIZE;
103 goto out;
104 }
105
106 memcpy(nla_data(attr), fprog->filter, flen);
107 out:
108 rcu_read_unlock();
109 return err;
110 }
111 EXPORT_SYMBOL(sock_diag_put_filterinfo);
112
113 struct broadcast_sk {
114 struct sock *sk;
115 struct work_struct work;
116 };
117
sock_diag_nlmsg_size(void)118 static size_t sock_diag_nlmsg_size(void)
119 {
120 return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
121 + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
122 + nla_total_size_64bit(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
123 }
124
sock_diag_broadcast_destroy_work(struct work_struct * work)125 static void sock_diag_broadcast_destroy_work(struct work_struct *work)
126 {
127 struct broadcast_sk *bsk =
128 container_of(work, struct broadcast_sk, work);
129 struct sock *sk = bsk->sk;
130 const struct sock_diag_handler *hndl;
131 struct sk_buff *skb;
132 const enum sknetlink_groups group = sock_diag_destroy_group(sk);
133 int err = -1;
134
135 WARN_ON(group == SKNLGRP_NONE);
136
137 skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
138 if (!skb)
139 goto out;
140
141 mutex_lock(&sock_diag_table_mutex);
142 hndl = sock_diag_handlers[sk->sk_family];
143 if (hndl && hndl->get_info)
144 err = hndl->get_info(skb, sk);
145 mutex_unlock(&sock_diag_table_mutex);
146
147 if (!err)
148 nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
149 GFP_KERNEL);
150 else
151 kfree_skb(skb);
152 out:
153 sk_destruct(sk);
154 kfree(bsk);
155 }
156
sock_diag_broadcast_destroy(struct sock * sk)157 void sock_diag_broadcast_destroy(struct sock *sk)
158 {
159 /* Note, this function is often called from an interrupt context. */
160 struct broadcast_sk *bsk =
161 kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
162 if (!bsk)
163 return sk_destruct(sk);
164 bsk->sk = sk;
165 INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
166 queue_work(broadcast_wq, &bsk->work);
167 }
168
sock_diag_register_inet_compat(int (* fn)(struct sk_buff * skb,struct nlmsghdr * nlh))169 void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
170 {
171 mutex_lock(&sock_diag_table_mutex);
172 inet_rcv_compat = fn;
173 mutex_unlock(&sock_diag_table_mutex);
174 }
175 EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
176
sock_diag_unregister_inet_compat(int (* fn)(struct sk_buff * skb,struct nlmsghdr * nlh))177 void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
178 {
179 mutex_lock(&sock_diag_table_mutex);
180 inet_rcv_compat = NULL;
181 mutex_unlock(&sock_diag_table_mutex);
182 }
183 EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
184
sock_diag_register(const struct sock_diag_handler * hndl)185 int sock_diag_register(const struct sock_diag_handler *hndl)
186 {
187 int err = 0;
188
189 if (hndl->family >= AF_MAX)
190 return -EINVAL;
191
192 mutex_lock(&sock_diag_table_mutex);
193 if (sock_diag_handlers[hndl->family])
194 err = -EBUSY;
195 else
196 WRITE_ONCE(sock_diag_handlers[hndl->family], hndl);
197 mutex_unlock(&sock_diag_table_mutex);
198
199 return err;
200 }
201 EXPORT_SYMBOL_GPL(sock_diag_register);
202
sock_diag_unregister(const struct sock_diag_handler * hnld)203 void sock_diag_unregister(const struct sock_diag_handler *hnld)
204 {
205 int family = hnld->family;
206
207 if (family >= AF_MAX)
208 return;
209
210 mutex_lock(&sock_diag_table_mutex);
211 BUG_ON(sock_diag_handlers[family] != hnld);
212 WRITE_ONCE(sock_diag_handlers[family], NULL);
213 mutex_unlock(&sock_diag_table_mutex);
214 }
215 EXPORT_SYMBOL_GPL(sock_diag_unregister);
216
__sock_diag_cmd(struct sk_buff * skb,struct nlmsghdr * nlh)217 static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
218 {
219 int err;
220 struct sock_diag_req *req = nlmsg_data(nlh);
221 const struct sock_diag_handler *hndl;
222
223 if (nlmsg_len(nlh) < sizeof(*req))
224 return -EINVAL;
225
226 if (req->sdiag_family >= AF_MAX)
227 return -EINVAL;
228 req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX);
229
230 if (READ_ONCE(sock_diag_handlers[req->sdiag_family]) == NULL)
231 sock_load_diag_module(req->sdiag_family, 0);
232
233 mutex_lock(&sock_diag_table_mutex);
234 hndl = sock_diag_handlers[req->sdiag_family];
235 if (hndl == NULL)
236 err = -ENOENT;
237 else if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY)
238 err = hndl->dump(skb, nlh);
239 else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy)
240 err = hndl->destroy(skb, nlh);
241 else
242 err = -EOPNOTSUPP;
243 mutex_unlock(&sock_diag_table_mutex);
244
245 return err;
246 }
247
sock_diag_rcv_msg(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)248 static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
249 struct netlink_ext_ack *extack)
250 {
251 int ret;
252
253 switch (nlh->nlmsg_type) {
254 case TCPDIAG_GETSOCK:
255 case DCCPDIAG_GETSOCK:
256 if (inet_rcv_compat == NULL)
257 sock_load_diag_module(AF_INET, 0);
258
259 mutex_lock(&sock_diag_table_mutex);
260 if (inet_rcv_compat != NULL)
261 ret = inet_rcv_compat(skb, nlh);
262 else
263 ret = -EOPNOTSUPP;
264 mutex_unlock(&sock_diag_table_mutex);
265
266 return ret;
267 case SOCK_DIAG_BY_FAMILY:
268 case SOCK_DESTROY:
269 return __sock_diag_cmd(skb, nlh);
270 default:
271 return -EINVAL;
272 }
273 }
274
275 static DEFINE_MUTEX(sock_diag_mutex);
276
sock_diag_rcv(struct sk_buff * skb)277 static void sock_diag_rcv(struct sk_buff *skb)
278 {
279 mutex_lock(&sock_diag_mutex);
280 netlink_rcv_skb(skb, &sock_diag_rcv_msg);
281 mutex_unlock(&sock_diag_mutex);
282 }
283
sock_diag_bind(struct net * net,int group)284 static int sock_diag_bind(struct net *net, int group)
285 {
286 switch (group) {
287 case SKNLGRP_INET_TCP_DESTROY:
288 case SKNLGRP_INET_UDP_DESTROY:
289 if (!READ_ONCE(sock_diag_handlers[AF_INET]))
290 sock_load_diag_module(AF_INET, 0);
291 break;
292 case SKNLGRP_INET6_TCP_DESTROY:
293 case SKNLGRP_INET6_UDP_DESTROY:
294 if (!READ_ONCE(sock_diag_handlers[AF_INET6]))
295 sock_load_diag_module(AF_INET6, 0);
296 break;
297 }
298 return 0;
299 }
300
sock_diag_destroy(struct sock * sk,int err)301 int sock_diag_destroy(struct sock *sk, int err)
302 {
303 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
304 return -EPERM;
305
306 if (!sk->sk_prot->diag_destroy)
307 return -EOPNOTSUPP;
308
309 return sk->sk_prot->diag_destroy(sk, err);
310 }
311 EXPORT_SYMBOL_GPL(sock_diag_destroy);
312
diag_net_init(struct net * net)313 static int __net_init diag_net_init(struct net *net)
314 {
315 struct netlink_kernel_cfg cfg = {
316 .groups = SKNLGRP_MAX,
317 .input = sock_diag_rcv,
318 .bind = sock_diag_bind,
319 .flags = NL_CFG_F_NONROOT_RECV,
320 };
321
322 net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
323 return net->diag_nlsk == NULL ? -ENOMEM : 0;
324 }
325
diag_net_exit(struct net * net)326 static void __net_exit diag_net_exit(struct net *net)
327 {
328 netlink_kernel_release(net->diag_nlsk);
329 net->diag_nlsk = NULL;
330 }
331
332 static struct pernet_operations diag_net_ops = {
333 .init = diag_net_init,
334 .exit = diag_net_exit,
335 };
336
sock_diag_init(void)337 static int __init sock_diag_init(void)
338 {
339 broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
340 BUG_ON(!broadcast_wq);
341 return register_pernet_subsys(&diag_net_ops);
342 }
343 device_initcall(sock_diag_init);
344