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 (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 (sk->sk_state == TCP_LISTEN) {
107 rql.udiag_rqueue = sk->sk_receive_queue.qlen;
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 = 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, 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 << 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 .owner = THIS_MODULE,
326 .family = AF_UNIX,
327 .dump = unix_diag_handler_dump,
328 };
329
unix_diag_init(void)330 static int __init unix_diag_init(void)
331 {
332 return sock_diag_register(&unix_diag_handler);
333 }
334
unix_diag_exit(void)335 static void __exit unix_diag_exit(void)
336 {
337 sock_diag_unregister(&unix_diag_handler);
338 }
339
340 module_init(unix_diag_init);
341 module_exit(unix_diag_exit);
342 MODULE_LICENSE("GPL");
343 MODULE_DESCRIPTION("UNIX socket monitoring via SOCK_DIAG");
344 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 1 /* AF_LOCAL */);
345