xref: /openbmc/linux/net/core/sock_diag.c (revision 68198dca)
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  
14  #include <linux/inet_diag.h>
15  #include <linux/sock_diag.h>
16  
17  static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
18  static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
19  static DEFINE_MUTEX(sock_diag_table_mutex);
20  static struct workqueue_struct *broadcast_wq;
21  
22  u64 sock_gen_cookie(struct sock *sk)
23  {
24  	while (1) {
25  		u64 res = atomic64_read(&sk->sk_cookie);
26  
27  		if (res)
28  			return res;
29  		res = atomic64_inc_return(&sock_net(sk)->cookie_gen);
30  		atomic64_cmpxchg(&sk->sk_cookie, 0, res);
31  	}
32  }
33  
34  int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
35  {
36  	u64 res;
37  
38  	if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
39  		return 0;
40  
41  	res = sock_gen_cookie(sk);
42  	if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
43  		return -ESTALE;
44  
45  	return 0;
46  }
47  EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
48  
49  void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
50  {
51  	u64 res = sock_gen_cookie(sk);
52  
53  	cookie[0] = (u32)res;
54  	cookie[1] = (u32)(res >> 32);
55  }
56  EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
57  
58  int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
59  {
60  	u32 mem[SK_MEMINFO_VARS];
61  
62  	sk_get_meminfo(sk, mem);
63  
64  	return nla_put(skb, attrtype, sizeof(mem), &mem);
65  }
66  EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
67  
68  int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
69  			     struct sk_buff *skb, int attrtype)
70  {
71  	struct sock_fprog_kern *fprog;
72  	struct sk_filter *filter;
73  	struct nlattr *attr;
74  	unsigned int flen;
75  	int err = 0;
76  
77  	if (!may_report_filterinfo) {
78  		nla_reserve(skb, attrtype, 0);
79  		return 0;
80  	}
81  
82  	rcu_read_lock();
83  	filter = rcu_dereference(sk->sk_filter);
84  	if (!filter)
85  		goto out;
86  
87  	fprog = filter->prog->orig_prog;
88  	if (!fprog)
89  		goto out;
90  
91  	flen = bpf_classic_proglen(fprog);
92  
93  	attr = nla_reserve(skb, attrtype, flen);
94  	if (attr == NULL) {
95  		err = -EMSGSIZE;
96  		goto out;
97  	}
98  
99  	memcpy(nla_data(attr), fprog->filter, flen);
100  out:
101  	rcu_read_unlock();
102  	return err;
103  }
104  EXPORT_SYMBOL(sock_diag_put_filterinfo);
105  
106  struct broadcast_sk {
107  	struct sock *sk;
108  	struct work_struct work;
109  };
110  
111  static size_t sock_diag_nlmsg_size(void)
112  {
113  	return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
114  	       + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
115  	       + nla_total_size_64bit(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
116  }
117  
118  static void sock_diag_broadcast_destroy_work(struct work_struct *work)
119  {
120  	struct broadcast_sk *bsk =
121  		container_of(work, struct broadcast_sk, work);
122  	struct sock *sk = bsk->sk;
123  	const struct sock_diag_handler *hndl;
124  	struct sk_buff *skb;
125  	const enum sknetlink_groups group = sock_diag_destroy_group(sk);
126  	int err = -1;
127  
128  	WARN_ON(group == SKNLGRP_NONE);
129  
130  	skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
131  	if (!skb)
132  		goto out;
133  
134  	mutex_lock(&sock_diag_table_mutex);
135  	hndl = sock_diag_handlers[sk->sk_family];
136  	if (hndl && hndl->get_info)
137  		err = hndl->get_info(skb, sk);
138  	mutex_unlock(&sock_diag_table_mutex);
139  
140  	if (!err)
141  		nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
142  				GFP_KERNEL);
143  	else
144  		kfree_skb(skb);
145  out:
146  	sk_destruct(sk);
147  	kfree(bsk);
148  }
149  
150  void sock_diag_broadcast_destroy(struct sock *sk)
151  {
152  	/* Note, this function is often called from an interrupt context. */
153  	struct broadcast_sk *bsk =
154  		kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
155  	if (!bsk)
156  		return sk_destruct(sk);
157  	bsk->sk = sk;
158  	INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
159  	queue_work(broadcast_wq, &bsk->work);
160  }
161  
162  void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
163  {
164  	mutex_lock(&sock_diag_table_mutex);
165  	inet_rcv_compat = fn;
166  	mutex_unlock(&sock_diag_table_mutex);
167  }
168  EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
169  
170  void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
171  {
172  	mutex_lock(&sock_diag_table_mutex);
173  	inet_rcv_compat = NULL;
174  	mutex_unlock(&sock_diag_table_mutex);
175  }
176  EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
177  
178  int sock_diag_register(const struct sock_diag_handler *hndl)
179  {
180  	int err = 0;
181  
182  	if (hndl->family >= AF_MAX)
183  		return -EINVAL;
184  
185  	mutex_lock(&sock_diag_table_mutex);
186  	if (sock_diag_handlers[hndl->family])
187  		err = -EBUSY;
188  	else
189  		sock_diag_handlers[hndl->family] = hndl;
190  	mutex_unlock(&sock_diag_table_mutex);
191  
192  	return err;
193  }
194  EXPORT_SYMBOL_GPL(sock_diag_register);
195  
196  void sock_diag_unregister(const struct sock_diag_handler *hnld)
197  {
198  	int family = hnld->family;
199  
200  	if (family >= AF_MAX)
201  		return;
202  
203  	mutex_lock(&sock_diag_table_mutex);
204  	BUG_ON(sock_diag_handlers[family] != hnld);
205  	sock_diag_handlers[family] = NULL;
206  	mutex_unlock(&sock_diag_table_mutex);
207  }
208  EXPORT_SYMBOL_GPL(sock_diag_unregister);
209  
210  static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
211  {
212  	int err;
213  	struct sock_diag_req *req = nlmsg_data(nlh);
214  	const struct sock_diag_handler *hndl;
215  
216  	if (nlmsg_len(nlh) < sizeof(*req))
217  		return -EINVAL;
218  
219  	if (req->sdiag_family >= AF_MAX)
220  		return -EINVAL;
221  
222  	if (sock_diag_handlers[req->sdiag_family] == NULL)
223  		request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
224  				NETLINK_SOCK_DIAG, req->sdiag_family);
225  
226  	mutex_lock(&sock_diag_table_mutex);
227  	hndl = sock_diag_handlers[req->sdiag_family];
228  	if (hndl == NULL)
229  		err = -ENOENT;
230  	else if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY)
231  		err = hndl->dump(skb, nlh);
232  	else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy)
233  		err = hndl->destroy(skb, nlh);
234  	else
235  		err = -EOPNOTSUPP;
236  	mutex_unlock(&sock_diag_table_mutex);
237  
238  	return err;
239  }
240  
241  static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
242  			     struct netlink_ext_ack *extack)
243  {
244  	int ret;
245  
246  	switch (nlh->nlmsg_type) {
247  	case TCPDIAG_GETSOCK:
248  	case DCCPDIAG_GETSOCK:
249  		if (inet_rcv_compat == NULL)
250  			request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
251  					NETLINK_SOCK_DIAG, AF_INET);
252  
253  		mutex_lock(&sock_diag_table_mutex);
254  		if (inet_rcv_compat != NULL)
255  			ret = inet_rcv_compat(skb, nlh);
256  		else
257  			ret = -EOPNOTSUPP;
258  		mutex_unlock(&sock_diag_table_mutex);
259  
260  		return ret;
261  	case SOCK_DIAG_BY_FAMILY:
262  	case SOCK_DESTROY:
263  		return __sock_diag_cmd(skb, nlh);
264  	default:
265  		return -EINVAL;
266  	}
267  }
268  
269  static DEFINE_MUTEX(sock_diag_mutex);
270  
271  static void sock_diag_rcv(struct sk_buff *skb)
272  {
273  	mutex_lock(&sock_diag_mutex);
274  	netlink_rcv_skb(skb, &sock_diag_rcv_msg);
275  	mutex_unlock(&sock_diag_mutex);
276  }
277  
278  static int sock_diag_bind(struct net *net, int group)
279  {
280  	switch (group) {
281  	case SKNLGRP_INET_TCP_DESTROY:
282  	case SKNLGRP_INET_UDP_DESTROY:
283  		if (!sock_diag_handlers[AF_INET])
284  			request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
285  				       NETLINK_SOCK_DIAG, AF_INET);
286  		break;
287  	case SKNLGRP_INET6_TCP_DESTROY:
288  	case SKNLGRP_INET6_UDP_DESTROY:
289  		if (!sock_diag_handlers[AF_INET6])
290  			request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
291  				       NETLINK_SOCK_DIAG, AF_INET);
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);
340