xref: /openbmc/linux/net/unix/diag.c (revision d8011254)
1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/types.h>
3 #include <linux/spinlock.h>
4 #include <linux/sock_diag.h>
5 #include <linux/unix_diag.h>
6 #include <linux/skbuff.h>
7 #include <linux/module.h>
8 #include <linux/uidgid.h>
9 #include <net/netlink.h>
10 #include <net/af_unix.h>
11 #include <net/tcp_states.h>
12 #include <net/sock.h>
13 
sk_diag_dump_name(struct sock * sk,struct sk_buff * nlskb)14 static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)
15 {
16 	/* might or might not have a hash table lock */
17 	struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
18 
19 	if (!addr)
20 		return 0;
21 
22 	return nla_put(nlskb, UNIX_DIAG_NAME,
23 		       addr->len - offsetof(struct sockaddr_un, sun_path),
24 		       addr->name->sun_path);
25 }
26 
sk_diag_dump_vfs(struct sock * sk,struct sk_buff * nlskb)27 static int sk_diag_dump_vfs(struct sock *sk, struct sk_buff *nlskb)
28 {
29 	struct dentry *dentry = unix_sk(sk)->path.dentry;
30 
31 	if (dentry) {
32 		struct unix_diag_vfs uv = {
33 			.udiag_vfs_ino = d_backing_inode(dentry)->i_ino,
34 			.udiag_vfs_dev = dentry->d_sb->s_dev,
35 		};
36 
37 		return nla_put(nlskb, UNIX_DIAG_VFS, sizeof(uv), &uv);
38 	}
39 
40 	return 0;
41 }
42 
sk_diag_dump_peer(struct sock * sk,struct sk_buff * nlskb)43 static int sk_diag_dump_peer(struct sock *sk, struct sk_buff *nlskb)
44 {
45 	struct sock *peer;
46 	int ino;
47 
48 	peer = unix_peer_get(sk);
49 	if (peer) {
50 		unix_state_lock(peer);
51 		ino = sock_i_ino(peer);
52 		unix_state_unlock(peer);
53 		sock_put(peer);
54 
55 		return nla_put_u32(nlskb, UNIX_DIAG_PEER, ino);
56 	}
57 
58 	return 0;
59 }
60 
sk_diag_dump_icons(struct sock * sk,struct sk_buff * nlskb)61 static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb)
62 {
63 	struct sk_buff *skb;
64 	struct nlattr *attr;
65 	u32 *buf;
66 	int i;
67 
68 	if (READ_ONCE(sk->sk_state) == TCP_LISTEN) {
69 		spin_lock(&sk->sk_receive_queue.lock);
70 
71 		attr = nla_reserve(nlskb, UNIX_DIAG_ICONS,
72 				   sk->sk_receive_queue.qlen * sizeof(u32));
73 		if (!attr)
74 			goto errout;
75 
76 		buf = nla_data(attr);
77 		i = 0;
78 		skb_queue_walk(&sk->sk_receive_queue, skb) {
79 			struct sock *req, *peer;
80 
81 			req = skb->sk;
82 			/*
83 			 * The state lock is outer for the same sk's
84 			 * queue lock. With the other's queue locked it's
85 			 * OK to lock the state.
86 			 */
87 			unix_state_lock_nested(req, U_LOCK_DIAG);
88 			peer = unix_sk(req)->peer;
89 			buf[i++] = (peer ? sock_i_ino(peer) : 0);
90 			unix_state_unlock(req);
91 		}
92 		spin_unlock(&sk->sk_receive_queue.lock);
93 	}
94 
95 	return 0;
96 
97 errout:
98 	spin_unlock(&sk->sk_receive_queue.lock);
99 	return -EMSGSIZE;
100 }
101 
sk_diag_show_rqlen(struct sock * sk,struct sk_buff * nlskb)102 static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb)
103 {
104 	struct unix_diag_rqlen rql;
105 
106 	if (READ_ONCE(sk->sk_state) == TCP_LISTEN) {
107 		rql.udiag_rqueue = skb_queue_len_lockless(&sk->sk_receive_queue);
108 		rql.udiag_wqueue = sk->sk_max_ack_backlog;
109 	} else {
110 		rql.udiag_rqueue = (u32) unix_inq_len(sk);
111 		rql.udiag_wqueue = (u32) unix_outq_len(sk);
112 	}
113 
114 	return nla_put(nlskb, UNIX_DIAG_RQLEN, sizeof(rql), &rql);
115 }
116 
sk_diag_dump_uid(struct sock * sk,struct sk_buff * nlskb,struct user_namespace * user_ns)117 static int sk_diag_dump_uid(struct sock *sk, struct sk_buff *nlskb,
118 			    struct user_namespace *user_ns)
119 {
120 	uid_t uid = from_kuid_munged(user_ns, sock_i_uid(sk));
121 	return nla_put(nlskb, UNIX_DIAG_UID, sizeof(uid_t), &uid);
122 }
123 
sk_diag_fill(struct sock * sk,struct sk_buff * skb,struct unix_diag_req * req,struct user_namespace * user_ns,u32 portid,u32 seq,u32 flags,int sk_ino)124 static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
125 			struct user_namespace *user_ns,
126 			u32 portid, u32 seq, u32 flags, int sk_ino)
127 {
128 	struct nlmsghdr *nlh;
129 	struct unix_diag_msg *rep;
130 
131 	nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
132 			flags);
133 	if (!nlh)
134 		return -EMSGSIZE;
135 
136 	rep = nlmsg_data(nlh);
137 	rep->udiag_family = AF_UNIX;
138 	rep->udiag_type = sk->sk_type;
139 	rep->udiag_state = READ_ONCE(sk->sk_state);
140 	rep->pad = 0;
141 	rep->udiag_ino = sk_ino;
142 	sock_diag_save_cookie(sk, rep->udiag_cookie);
143 
144 	if ((req->udiag_show & UDIAG_SHOW_NAME) &&
145 	    sk_diag_dump_name(sk, skb))
146 		goto out_nlmsg_trim;
147 
148 	if ((req->udiag_show & UDIAG_SHOW_VFS) &&
149 	    sk_diag_dump_vfs(sk, skb))
150 		goto out_nlmsg_trim;
151 
152 	if ((req->udiag_show & UDIAG_SHOW_PEER) &&
153 	    sk_diag_dump_peer(sk, skb))
154 		goto out_nlmsg_trim;
155 
156 	if ((req->udiag_show & UDIAG_SHOW_ICONS) &&
157 	    sk_diag_dump_icons(sk, skb))
158 		goto out_nlmsg_trim;
159 
160 	if ((req->udiag_show & UDIAG_SHOW_RQLEN) &&
161 	    sk_diag_show_rqlen(sk, skb))
162 		goto out_nlmsg_trim;
163 
164 	if ((req->udiag_show & UDIAG_SHOW_MEMINFO) &&
165 	    sock_diag_put_meminfo(sk, skb, UNIX_DIAG_MEMINFO))
166 		goto out_nlmsg_trim;
167 
168 	if (nla_put_u8(skb, UNIX_DIAG_SHUTDOWN, READ_ONCE(sk->sk_shutdown)))
169 		goto out_nlmsg_trim;
170 
171 	if ((req->udiag_show & UDIAG_SHOW_UID) &&
172 	    sk_diag_dump_uid(sk, skb, user_ns))
173 		goto out_nlmsg_trim;
174 
175 	nlmsg_end(skb, nlh);
176 	return 0;
177 
178 out_nlmsg_trim:
179 	nlmsg_cancel(skb, nlh);
180 	return -EMSGSIZE;
181 }
182 
sk_diag_dump(struct sock * sk,struct sk_buff * skb,struct unix_diag_req * req,struct user_namespace * user_ns,u32 portid,u32 seq,u32 flags)183 static int sk_diag_dump(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
184 			struct user_namespace *user_ns,
185 			u32 portid, u32 seq, u32 flags)
186 {
187 	int sk_ino;
188 
189 	unix_state_lock(sk);
190 	sk_ino = sock_i_ino(sk);
191 	unix_state_unlock(sk);
192 
193 	if (!sk_ino)
194 		return 0;
195 
196 	return sk_diag_fill(sk, skb, req, user_ns, portid, seq, flags, sk_ino);
197 }
198 
unix_diag_dump(struct sk_buff * skb,struct netlink_callback * cb)199 static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
200 {
201 	struct net *net = sock_net(skb->sk);
202 	int num, s_num, slot, s_slot;
203 	struct unix_diag_req *req;
204 
205 	req = nlmsg_data(cb->nlh);
206 
207 	s_slot = cb->args[0];
208 	num = s_num = cb->args[1];
209 
210 	for (slot = s_slot; slot < UNIX_HASH_SIZE; s_num = 0, slot++) {
211 		struct sock *sk;
212 
213 		num = 0;
214 		spin_lock(&net->unx.table.locks[slot]);
215 		sk_for_each(sk, &net->unx.table.buckets[slot]) {
216 			if (num < s_num)
217 				goto next;
218 			if (!(req->udiag_states & (1 << READ_ONCE(sk->sk_state))))
219 				goto next;
220 			if (sk_diag_dump(sk, skb, req, sk_user_ns(skb->sk),
221 					 NETLINK_CB(cb->skb).portid,
222 					 cb->nlh->nlmsg_seq,
223 					 NLM_F_MULTI) < 0) {
224 				spin_unlock(&net->unx.table.locks[slot]);
225 				goto done;
226 			}
227 next:
228 			num++;
229 		}
230 		spin_unlock(&net->unx.table.locks[slot]);
231 	}
232 done:
233 	cb->args[0] = slot;
234 	cb->args[1] = num;
235 
236 	return skb->len;
237 }
238 
unix_lookup_by_ino(struct net * net,unsigned int ino)239 static struct sock *unix_lookup_by_ino(struct net *net, unsigned int ino)
240 {
241 	struct sock *sk;
242 	int i;
243 
244 	for (i = 0; i < UNIX_HASH_SIZE; i++) {
245 		spin_lock(&net->unx.table.locks[i]);
246 		sk_for_each(sk, &net->unx.table.buckets[i]) {
247 			if (ino == sock_i_ino(sk)) {
248 				sock_hold(sk);
249 				spin_unlock(&net->unx.table.locks[i]);
250 				return sk;
251 			}
252 		}
253 		spin_unlock(&net->unx.table.locks[i]);
254 	}
255 	return NULL;
256 }
257 
unix_diag_get_exact(struct sk_buff * in_skb,const struct nlmsghdr * nlh,struct unix_diag_req * req)258 static int unix_diag_get_exact(struct sk_buff *in_skb,
259 			       const struct nlmsghdr *nlh,
260 			       struct unix_diag_req *req)
261 {
262 	struct net *net = sock_net(in_skb->sk);
263 	unsigned int extra_len;
264 	struct sk_buff *rep;
265 	struct sock *sk;
266 	int err;
267 
268 	err = -EINVAL;
269 	if (req->udiag_ino == 0)
270 		goto out_nosk;
271 
272 	sk = unix_lookup_by_ino(net, req->udiag_ino);
273 	err = -ENOENT;
274 	if (sk == NULL)
275 		goto out_nosk;
276 
277 	err = sock_diag_check_cookie(sk, req->udiag_cookie);
278 	if (err)
279 		goto out;
280 
281 	extra_len = 256;
282 again:
283 	err = -ENOMEM;
284 	rep = nlmsg_new(sizeof(struct unix_diag_msg) + extra_len, GFP_KERNEL);
285 	if (!rep)
286 		goto out;
287 
288 	err = sk_diag_fill(sk, rep, req, sk_user_ns(NETLINK_CB(in_skb).sk),
289 			   NETLINK_CB(in_skb).portid,
290 			   nlh->nlmsg_seq, 0, req->udiag_ino);
291 	if (err < 0) {
292 		nlmsg_free(rep);
293 		extra_len += 256;
294 		if (extra_len >= PAGE_SIZE)
295 			goto out;
296 
297 		goto again;
298 	}
299 	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
300 
301 out:
302 	if (sk)
303 		sock_put(sk);
304 out_nosk:
305 	return err;
306 }
307 
unix_diag_handler_dump(struct sk_buff * skb,struct nlmsghdr * h)308 static int unix_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
309 {
310 	int hdrlen = sizeof(struct unix_diag_req);
311 
312 	if (nlmsg_len(h) < hdrlen)
313 		return -EINVAL;
314 
315 	if (h->nlmsg_flags & NLM_F_DUMP) {
316 		struct netlink_dump_control c = {
317 			.dump = unix_diag_dump,
318 		};
319 		return netlink_dump_start(sock_net(skb->sk)->diag_nlsk, skb, h, &c);
320 	} else
321 		return unix_diag_get_exact(skb, h, nlmsg_data(h));
322 }
323 
324 static const struct sock_diag_handler unix_diag_handler = {
325 	.family = AF_UNIX,
326 	.dump = unix_diag_handler_dump,
327 };
328 
unix_diag_init(void)329 static int __init unix_diag_init(void)
330 {
331 	return sock_diag_register(&unix_diag_handler);
332 }
333 
unix_diag_exit(void)334 static void __exit unix_diag_exit(void)
335 {
336 	sock_diag_unregister(&unix_diag_handler);
337 }
338 
339 module_init(unix_diag_init);
340 module_exit(unix_diag_exit);
341 MODULE_LICENSE("GPL");
342 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 1 /* AF_LOCAL */);
343