1 // SPDX-License-Identifier: GPL-2.0-only
2
3 #include <linux/dcache.h>
4 #include <linux/module.h>
5 #include <linux/skbuff.h>
6 #include <linux/sock_diag.h>
7 #include <linux/types.h>
8 #include <linux/user_namespace.h>
9 #include <net/af_unix.h>
10 #include <net/netlink.h>
11 #include <net/tcp_states.h>
12 #include <uapi/linux/unix_diag.h>
13
14 #include "af_unix.h"
15
sk_diag_dump_name(struct sock * sk,struct sk_buff * nlskb)16 static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb)
17 {
18 /* might or might not have a hash table lock */
19 struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr);
20
21 if (!addr)
22 return 0;
23
24 return nla_put(nlskb, UNIX_DIAG_NAME,
25 addr->len - offsetof(struct sockaddr_un, sun_path),
26 addr->name->sun_path);
27 }
28
sk_diag_dump_vfs(struct sock * sk,struct sk_buff * nlskb)29 static int sk_diag_dump_vfs(struct sock *sk, struct sk_buff *nlskb)
30 {
31 struct unix_diag_vfs uv;
32 struct dentry *dentry;
33 bool have_vfs = false;
34
35 unix_state_lock(sk);
36 dentry = unix_sk(sk)->path.dentry;
37 if (dentry) {
38 uv.udiag_vfs_ino = d_backing_inode(dentry)->i_ino;
39 uv.udiag_vfs_dev = dentry->d_sb->s_dev;
40 have_vfs = true;
41 }
42 unix_state_unlock(sk);
43
44 if (!have_vfs)
45 return 0;
46
47 return nla_put(nlskb, UNIX_DIAG_VFS, sizeof(uv), &uv);
48 }
49
sk_diag_dump_peer(struct sock * sk,struct sk_buff * nlskb)50 static int sk_diag_dump_peer(struct sock *sk, struct sk_buff *nlskb)
51 {
52 struct sock *peer;
53 u64 ino;
54
55 peer = unix_peer_get(sk);
56 if (peer) {
57 ino = sock_i_ino(peer);
58 sock_put(peer);
59
60 return nla_put_u32(nlskb, UNIX_DIAG_PEER, ino);
61 }
62
63 return 0;
64 }
65
sk_diag_dump_icons(struct sock * sk,struct sk_buff * nlskb)66 static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb)
67 {
68 struct sk_buff *skb;
69 struct nlattr *attr;
70 u32 *buf;
71 int i;
72
73 if (READ_ONCE(sk->sk_state) == TCP_LISTEN) {
74 spin_lock(&sk->sk_receive_queue.lock);
75
76 attr = nla_reserve(nlskb, UNIX_DIAG_ICONS,
77 sk->sk_receive_queue.qlen * sizeof(u32));
78 if (!attr)
79 goto errout;
80
81 buf = nla_data(attr);
82 i = 0;
83 skb_queue_walk(&sk->sk_receive_queue, skb)
84 buf[i++] = sock_i_ino(unix_peer(skb->sk));
85
86 spin_unlock(&sk->sk_receive_queue.lock);
87 }
88
89 return 0;
90
91 errout:
92 spin_unlock(&sk->sk_receive_queue.lock);
93 return -EMSGSIZE;
94 }
95
sk_diag_show_rqlen(struct sock * sk,struct sk_buff * nlskb)96 static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb)
97 {
98 struct unix_diag_rqlen rql;
99
100 if (READ_ONCE(sk->sk_state) == TCP_LISTEN) {
101 rql.udiag_rqueue = skb_queue_len_lockless(&sk->sk_receive_queue);
102 rql.udiag_wqueue = sk->sk_max_ack_backlog;
103 } else {
104 rql.udiag_rqueue = (u32) unix_inq_len(sk);
105 rql.udiag_wqueue = (u32) unix_outq_len(sk);
106 }
107
108 return nla_put(nlskb, UNIX_DIAG_RQLEN, sizeof(rql), &rql);
109 }
110
sk_diag_dump_uid(struct sock * sk,struct sk_buff * nlskb,struct user_namespace * user_ns)111 static int sk_diag_dump_uid(struct sock *sk, struct sk_buff *nlskb,
112 struct user_namespace *user_ns)
113 {
114 uid_t uid = from_kuid_munged(user_ns, sk_uid(sk));
115 return nla_put(nlskb, UNIX_DIAG_UID, sizeof(uid_t), &uid);
116 }
117
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,u64 sk_ino)118 static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
119 struct user_namespace *user_ns,
120 u32 portid, u32 seq, u32 flags, u64 sk_ino)
121 {
122 struct nlmsghdr *nlh;
123 struct unix_diag_msg *rep;
124
125 nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
126 flags);
127 if (!nlh)
128 return -EMSGSIZE;
129
130 rep = nlmsg_data(nlh);
131 rep->udiag_family = AF_UNIX;
132 rep->udiag_type = sk->sk_type;
133 rep->udiag_state = READ_ONCE(sk->sk_state);
134 rep->pad = 0;
135 rep->udiag_ino = sk_ino;
136 sock_diag_save_cookie(sk, rep->udiag_cookie);
137
138 if ((req->udiag_show & UDIAG_SHOW_NAME) &&
139 sk_diag_dump_name(sk, skb))
140 goto out_nlmsg_trim;
141
142 if ((req->udiag_show & UDIAG_SHOW_VFS) &&
143 sk_diag_dump_vfs(sk, skb))
144 goto out_nlmsg_trim;
145
146 if ((req->udiag_show & UDIAG_SHOW_PEER) &&
147 sk_diag_dump_peer(sk, skb))
148 goto out_nlmsg_trim;
149
150 if ((req->udiag_show & UDIAG_SHOW_ICONS) &&
151 sk_diag_dump_icons(sk, skb))
152 goto out_nlmsg_trim;
153
154 if ((req->udiag_show & UDIAG_SHOW_RQLEN) &&
155 sk_diag_show_rqlen(sk, skb))
156 goto out_nlmsg_trim;
157
158 if ((req->udiag_show & UDIAG_SHOW_MEMINFO) &&
159 sock_diag_put_meminfo(sk, skb, UNIX_DIAG_MEMINFO))
160 goto out_nlmsg_trim;
161
162 if (nla_put_u8(skb, UNIX_DIAG_SHUTDOWN, READ_ONCE(sk->sk_shutdown)))
163 goto out_nlmsg_trim;
164
165 if ((req->udiag_show & UDIAG_SHOW_UID) &&
166 sk_diag_dump_uid(sk, skb, user_ns))
167 goto out_nlmsg_trim;
168
169 nlmsg_end(skb, nlh);
170 return 0;
171
172 out_nlmsg_trim:
173 nlmsg_cancel(skb, nlh);
174 return -EMSGSIZE;
175 }
176
unix_diag_dump(struct sk_buff * skb,struct netlink_callback * cb)177 static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
178 {
179 struct net *net = sock_net(skb->sk);
180 int num, s_num, slot, s_slot;
181 struct unix_diag_req *req;
182
183 req = nlmsg_data(cb->nlh);
184
185 s_slot = cb->args[0];
186 num = s_num = cb->args[1];
187
188 for (slot = s_slot; slot < UNIX_HASH_SIZE; s_num = 0, slot++) {
189 struct sock *sk;
190
191 num = 0;
192 spin_lock(&net->unx.table.locks[slot]);
193 sk_for_each(sk, &net->unx.table.buckets[slot]) {
194 u64 sk_ino;
195
196 if (num < s_num)
197 goto next;
198
199 if (!(req->udiag_states & (1 << READ_ONCE(sk->sk_state))))
200 goto next;
201
202 sk_ino = sock_i_ino(sk);
203 if (!sk_ino)
204 goto next;
205
206 if (sk_diag_fill(sk, skb, req, sk_user_ns(skb->sk),
207 NETLINK_CB(cb->skb).portid,
208 cb->nlh->nlmsg_seq,
209 NLM_F_MULTI, sk_ino) < 0) {
210 spin_unlock(&net->unx.table.locks[slot]);
211 goto done;
212 }
213 next:
214 num++;
215 }
216 spin_unlock(&net->unx.table.locks[slot]);
217 }
218 done:
219 cb->args[0] = slot;
220 cb->args[1] = num;
221
222 return skb->len;
223 }
224
unix_lookup_by_ino(struct net * net,unsigned int ino)225 static struct sock *unix_lookup_by_ino(struct net *net, unsigned int ino)
226 {
227 struct sock *sk;
228 int i;
229
230 for (i = 0; i < UNIX_HASH_SIZE; i++) {
231 spin_lock(&net->unx.table.locks[i]);
232 sk_for_each(sk, &net->unx.table.buckets[i]) {
233 if (ino == sock_i_ino(sk)) {
234 sock_hold(sk);
235 spin_unlock(&net->unx.table.locks[i]);
236 return sk;
237 }
238 }
239 spin_unlock(&net->unx.table.locks[i]);
240 }
241 return NULL;
242 }
243
unix_diag_get_exact(struct sk_buff * in_skb,const struct nlmsghdr * nlh,struct unix_diag_req * req)244 static int unix_diag_get_exact(struct sk_buff *in_skb,
245 const struct nlmsghdr *nlh,
246 struct unix_diag_req *req)
247 {
248 struct net *net = sock_net(in_skb->sk);
249 unsigned int extra_len;
250 struct sk_buff *rep;
251 struct sock *sk;
252 int err;
253
254 err = -EINVAL;
255 if (req->udiag_ino == 0)
256 goto out_nosk;
257
258 sk = unix_lookup_by_ino(net, req->udiag_ino);
259 err = -ENOENT;
260 if (sk == NULL)
261 goto out_nosk;
262
263 err = sock_diag_check_cookie(sk, req->udiag_cookie);
264 if (err)
265 goto out;
266
267 extra_len = 256;
268 again:
269 err = -ENOMEM;
270 rep = nlmsg_new(sizeof(struct unix_diag_msg) + extra_len, GFP_KERNEL);
271 if (!rep)
272 goto out;
273
274 err = sk_diag_fill(sk, rep, req, sk_user_ns(NETLINK_CB(in_skb).sk),
275 NETLINK_CB(in_skb).portid,
276 nlh->nlmsg_seq, 0, req->udiag_ino);
277 if (err < 0) {
278 nlmsg_free(rep);
279 extra_len += 256;
280 if (extra_len >= PAGE_SIZE)
281 goto out;
282
283 goto again;
284 }
285 err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
286
287 out:
288 if (sk)
289 sock_put(sk);
290 out_nosk:
291 return err;
292 }
293
unix_diag_handler_dump(struct sk_buff * skb,struct nlmsghdr * h)294 static int unix_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
295 {
296 int hdrlen = sizeof(struct unix_diag_req);
297
298 if (nlmsg_len(h) < hdrlen)
299 return -EINVAL;
300
301 if (h->nlmsg_flags & NLM_F_DUMP) {
302 struct netlink_dump_control c = {
303 .dump = unix_diag_dump,
304 };
305 return netlink_dump_start(sock_net(skb->sk)->diag_nlsk, skb, h, &c);
306 } else
307 return unix_diag_get_exact(skb, h, nlmsg_data(h));
308 }
309
310 static const struct sock_diag_handler unix_diag_handler = {
311 .owner = THIS_MODULE,
312 .family = AF_UNIX,
313 .dump = unix_diag_handler_dump,
314 };
315
unix_diag_init(void)316 static int __init unix_diag_init(void)
317 {
318 return sock_diag_register(&unix_diag_handler);
319 }
320
unix_diag_exit(void)321 static void __exit unix_diag_exit(void)
322 {
323 sock_diag_unregister(&unix_diag_handler);
324 }
325
326 module_init(unix_diag_init);
327 module_exit(unix_diag_exit);
328 MODULE_LICENSE("GPL");
329 MODULE_DESCRIPTION("UNIX socket monitoring via SOCK_DIAG");
330 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 1 /* AF_LOCAL */);
331