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 __rcu *sock_diag_handlers[AF_MAX]; |
20 | |
21 | static struct sock_diag_inet_compat __rcu *inet_rcv_compat; |
22 | |
23 | static struct workqueue_struct *broadcast_wq; |
24 | |
25 | DEFINE_COOKIE(sock_cookie); |
26 | |
27 | u64 __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 | |
42 | int 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 | } |
55 | EXPORT_SYMBOL_GPL(sock_diag_check_cookie); |
56 | |
57 | void 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 | } |
64 | EXPORT_SYMBOL_GPL(sock_diag_save_cookie); |
65 | |
66 | int 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 | } |
74 | EXPORT_SYMBOL_GPL(sock_diag_put_meminfo); |
75 | |
76 | int 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(nla_data(attr), fprog->filter, flen); |
108 | out: |
109 | rcu_read_unlock(); |
110 | return err; |
111 | } |
112 | EXPORT_SYMBOL(sock_diag_put_filterinfo); |
113 | |
114 | struct broadcast_sk { |
115 | struct sock *sk; |
116 | struct work_struct work; |
117 | }; |
118 | |
119 | static 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 | |
126 | static 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 | |
139 | static void sock_diag_unlock_handler(const struct sock_diag_handler *handler) |
140 | { |
141 | module_put(module: handler->owner); |
142 | } |
143 | |
144 | static 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); |
171 | out: |
172 | sk_destruct(sk); |
173 | kfree(objp: bsk); |
174 | } |
175 | |
176 | void 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(size: 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 | |
188 | void sock_diag_register_inet_compat(const struct sock_diag_inet_compat *ptr) |
189 | { |
190 | xchg((__force const struct sock_diag_inet_compat **)&inet_rcv_compat, |
191 | ptr); |
192 | } |
193 | EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat); |
194 | |
195 | void sock_diag_unregister_inet_compat(const struct sock_diag_inet_compat *ptr) |
196 | { |
197 | const struct sock_diag_inet_compat *old; |
198 | |
199 | old = xchg((__force const struct sock_diag_inet_compat **)&inet_rcv_compat, |
200 | NULL); |
201 | WARN_ON_ONCE(old != ptr); |
202 | } |
203 | EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat); |
204 | |
205 | int sock_diag_register(const struct sock_diag_handler *hndl) |
206 | { |
207 | int family = hndl->family; |
208 | |
209 | if (family >= AF_MAX) |
210 | return -EINVAL; |
211 | |
212 | return !cmpxchg((const struct sock_diag_handler **) |
213 | &sock_diag_handlers[family], |
214 | NULL, hndl) ? 0 : -EBUSY; |
215 | } |
216 | EXPORT_SYMBOL_GPL(sock_diag_register); |
217 | |
218 | void sock_diag_unregister(const struct sock_diag_handler *hndl) |
219 | { |
220 | int family = hndl->family; |
221 | |
222 | if (family >= AF_MAX) |
223 | return; |
224 | |
225 | xchg((const struct sock_diag_handler **)&sock_diag_handlers[family], |
226 | NULL); |
227 | } |
228 | EXPORT_SYMBOL_GPL(sock_diag_unregister); |
229 | |
230 | static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh) |
231 | { |
232 | int err; |
233 | struct sock_diag_req *req = nlmsg_data(nlh); |
234 | const struct sock_diag_handler *hndl; |
235 | |
236 | if (nlmsg_len(nlh) < sizeof(*req)) |
237 | return -EINVAL; |
238 | |
239 | if (req->sdiag_family >= AF_MAX) |
240 | return -EINVAL; |
241 | req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX); |
242 | |
243 | if (!rcu_access_pointer(sock_diag_handlers[req->sdiag_family])) |
244 | sock_load_diag_module(family: req->sdiag_family, protocol: 0); |
245 | |
246 | hndl = sock_diag_lock_handler(family: req->sdiag_family); |
247 | if (hndl == NULL) |
248 | return -ENOENT; |
249 | |
250 | if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY) |
251 | err = hndl->dump(skb, nlh); |
252 | else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy) |
253 | err = hndl->destroy(skb, nlh); |
254 | else |
255 | err = -EOPNOTSUPP; |
256 | sock_diag_unlock_handler(handler: hndl); |
257 | |
258 | return err; |
259 | } |
260 | |
261 | static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, |
262 | struct netlink_ext_ack *extack) |
263 | { |
264 | const struct sock_diag_inet_compat *ptr; |
265 | int ret; |
266 | |
267 | switch (nlh->nlmsg_type) { |
268 | case TCPDIAG_GETSOCK: |
269 | case DCCPDIAG_GETSOCK: |
270 | |
271 | if (!rcu_access_pointer(inet_rcv_compat)) |
272 | sock_load_diag_module(AF_INET, protocol: 0); |
273 | |
274 | rcu_read_lock(); |
275 | ptr = rcu_dereference(inet_rcv_compat); |
276 | if (ptr && !try_module_get(module: ptr->owner)) |
277 | ptr = NULL; |
278 | rcu_read_unlock(); |
279 | |
280 | ret = -EOPNOTSUPP; |
281 | if (ptr) { |
282 | ret = ptr->fn(skb, nlh); |
283 | module_put(module: ptr->owner); |
284 | } |
285 | |
286 | return ret; |
287 | case SOCK_DIAG_BY_FAMILY: |
288 | case SOCK_DESTROY: |
289 | return __sock_diag_cmd(skb, nlh); |
290 | default: |
291 | return -EINVAL; |
292 | } |
293 | } |
294 | |
295 | static void sock_diag_rcv(struct sk_buff *skb) |
296 | { |
297 | netlink_rcv_skb(skb, cb: &sock_diag_rcv_msg); |
298 | } |
299 | |
300 | static int sock_diag_bind(struct net *net, int group) |
301 | { |
302 | switch (group) { |
303 | case SKNLGRP_INET_TCP_DESTROY: |
304 | case SKNLGRP_INET_UDP_DESTROY: |
305 | if (!rcu_access_pointer(sock_diag_handlers[AF_INET])) |
306 | sock_load_diag_module(AF_INET, protocol: 0); |
307 | break; |
308 | case SKNLGRP_INET6_TCP_DESTROY: |
309 | case SKNLGRP_INET6_UDP_DESTROY: |
310 | if (!rcu_access_pointer(sock_diag_handlers[AF_INET6])) |
311 | sock_load_diag_module(AF_INET6, protocol: 0); |
312 | break; |
313 | } |
314 | return 0; |
315 | } |
316 | |
317 | int sock_diag_destroy(struct sock *sk, int err) |
318 | { |
319 | if (!ns_capable(ns: sock_net(sk)->user_ns, CAP_NET_ADMIN)) |
320 | return -EPERM; |
321 | |
322 | if (!sk->sk_prot->diag_destroy) |
323 | return -EOPNOTSUPP; |
324 | |
325 | return sk->sk_prot->diag_destroy(sk, err); |
326 | } |
327 | EXPORT_SYMBOL_GPL(sock_diag_destroy); |
328 | |
329 | static int __net_init diag_net_init(struct net *net) |
330 | { |
331 | struct netlink_kernel_cfg cfg = { |
332 | .groups = SKNLGRP_MAX, |
333 | .input = sock_diag_rcv, |
334 | .bind = sock_diag_bind, |
335 | .flags = NL_CFG_F_NONROOT_RECV, |
336 | }; |
337 | |
338 | net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, cfg: &cfg); |
339 | return net->diag_nlsk == NULL ? -ENOMEM : 0; |
340 | } |
341 | |
342 | static void __net_exit diag_net_exit(struct net *net) |
343 | { |
344 | netlink_kernel_release(sk: net->diag_nlsk); |
345 | net->diag_nlsk = NULL; |
346 | } |
347 | |
348 | static struct pernet_operations diag_net_ops = { |
349 | .init = diag_net_init, |
350 | .exit = diag_net_exit, |
351 | }; |
352 | |
353 | static int __init sock_diag_init(void) |
354 | { |
355 | broadcast_wq = alloc_workqueue(fmt: "sock_diag_events" , flags: 0, max_active: 0); |
356 | BUG_ON(!broadcast_wq); |
357 | return register_pernet_subsys(&diag_net_ops); |
358 | } |
359 | device_initcall(sock_diag_init); |
360 | |