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
16static 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(skb: nlskb, attrtype: UNIX_DIAG_NAME,
25 attrlen: addr->len - offsetof(struct sockaddr_un, sun_path),
26 data: addr->name->sun_path);
27}
28
29static int sk_diag_dump_vfs(struct sock *sk, struct sk_buff *nlskb)
30{
31 struct dentry *dentry = unix_sk(sk)->path.dentry;
32
33 if (dentry) {
34 struct unix_diag_vfs uv = {
35 .udiag_vfs_ino = d_backing_inode(upper: dentry)->i_ino,
36 .udiag_vfs_dev = dentry->d_sb->s_dev,
37 };
38
39 return nla_put(skb: nlskb, attrtype: UNIX_DIAG_VFS, attrlen: sizeof(uv), data: &uv);
40 }
41
42 return 0;
43}
44
45static int sk_diag_dump_peer(struct sock *sk, struct sk_buff *nlskb)
46{
47 struct sock *peer;
48 int ino;
49
50 peer = unix_peer_get(sk);
51 if (peer) {
52 ino = sock_i_ino(sk: peer);
53 sock_put(sk: peer);
54
55 return nla_put_u32(skb: nlskb, attrtype: UNIX_DIAG_PEER, value: ino);
56 }
57
58 return 0;
59}
60
61static 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(lock: &sk->sk_receive_queue.lock);
70
71 attr = nla_reserve(skb: nlskb, attrtype: UNIX_DIAG_ICONS,
72 attrlen: sk->sk_receive_queue.qlen * sizeof(u32));
73 if (!attr)
74 goto errout;
75
76 buf = nla_data(nla: attr);
77 i = 0;
78 skb_queue_walk(&sk->sk_receive_queue, skb)
79 buf[i++] = sock_i_ino(unix_peer(skb->sk));
80
81 spin_unlock(lock: &sk->sk_receive_queue.lock);
82 }
83
84 return 0;
85
86errout:
87 spin_unlock(lock: &sk->sk_receive_queue.lock);
88 return -EMSGSIZE;
89}
90
91static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb)
92{
93 struct unix_diag_rqlen rql;
94
95 if (READ_ONCE(sk->sk_state) == TCP_LISTEN) {
96 rql.udiag_rqueue = skb_queue_len_lockless(list_: &sk->sk_receive_queue);
97 rql.udiag_wqueue = sk->sk_max_ack_backlog;
98 } else {
99 rql.udiag_rqueue = (u32) unix_inq_len(sk);
100 rql.udiag_wqueue = (u32) unix_outq_len(sk);
101 }
102
103 return nla_put(skb: nlskb, attrtype: UNIX_DIAG_RQLEN, attrlen: sizeof(rql), data: &rql);
104}
105
106static int sk_diag_dump_uid(struct sock *sk, struct sk_buff *nlskb,
107 struct user_namespace *user_ns)
108{
109 uid_t uid = from_kuid_munged(to: user_ns, uid: sk_uid(sk));
110 return nla_put(skb: nlskb, attrtype: UNIX_DIAG_UID, attrlen: sizeof(uid_t), data: &uid);
111}
112
113static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
114 struct user_namespace *user_ns,
115 u32 portid, u32 seq, u32 flags, int sk_ino)
116{
117 struct nlmsghdr *nlh;
118 struct unix_diag_msg *rep;
119
120 nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, payload: sizeof(*rep),
121 flags);
122 if (!nlh)
123 return -EMSGSIZE;
124
125 rep = nlmsg_data(nlh);
126 rep->udiag_family = AF_UNIX;
127 rep->udiag_type = sk->sk_type;
128 rep->udiag_state = READ_ONCE(sk->sk_state);
129 rep->pad = 0;
130 rep->udiag_ino = sk_ino;
131 sock_diag_save_cookie(sk, cookie: rep->udiag_cookie);
132
133 if ((req->udiag_show & UDIAG_SHOW_NAME) &&
134 sk_diag_dump_name(sk, nlskb: skb))
135 goto out_nlmsg_trim;
136
137 if ((req->udiag_show & UDIAG_SHOW_VFS) &&
138 sk_diag_dump_vfs(sk, nlskb: skb))
139 goto out_nlmsg_trim;
140
141 if ((req->udiag_show & UDIAG_SHOW_PEER) &&
142 sk_diag_dump_peer(sk, nlskb: skb))
143 goto out_nlmsg_trim;
144
145 if ((req->udiag_show & UDIAG_SHOW_ICONS) &&
146 sk_diag_dump_icons(sk, nlskb: skb))
147 goto out_nlmsg_trim;
148
149 if ((req->udiag_show & UDIAG_SHOW_RQLEN) &&
150 sk_diag_show_rqlen(sk, nlskb: skb))
151 goto out_nlmsg_trim;
152
153 if ((req->udiag_show & UDIAG_SHOW_MEMINFO) &&
154 sock_diag_put_meminfo(sk, skb, attr: UNIX_DIAG_MEMINFO))
155 goto out_nlmsg_trim;
156
157 if (nla_put_u8(skb, attrtype: UNIX_DIAG_SHUTDOWN, READ_ONCE(sk->sk_shutdown)))
158 goto out_nlmsg_trim;
159
160 if ((req->udiag_show & UDIAG_SHOW_UID) &&
161 sk_diag_dump_uid(sk, nlskb: skb, user_ns))
162 goto out_nlmsg_trim;
163
164 nlmsg_end(skb, nlh);
165 return 0;
166
167out_nlmsg_trim:
168 nlmsg_cancel(skb, nlh);
169 return -EMSGSIZE;
170}
171
172static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
173{
174 struct net *net = sock_net(sk: skb->sk);
175 int num, s_num, slot, s_slot;
176 struct unix_diag_req *req;
177
178 req = nlmsg_data(nlh: cb->nlh);
179
180 s_slot = cb->args[0];
181 num = s_num = cb->args[1];
182
183 for (slot = s_slot; slot < UNIX_HASH_SIZE; s_num = 0, slot++) {
184 struct sock *sk;
185
186 num = 0;
187 spin_lock(lock: &net->unx.table.locks[slot]);
188 sk_for_each(sk, &net->unx.table.buckets[slot]) {
189 int sk_ino;
190
191 if (num < s_num)
192 goto next;
193
194 if (!(req->udiag_states & (1 << READ_ONCE(sk->sk_state))))
195 goto next;
196
197 sk_ino = sock_i_ino(sk);
198 if (!sk_ino)
199 goto next;
200
201 if (sk_diag_fill(sk, skb, req, user_ns: sk_user_ns(sk: skb->sk),
202 NETLINK_CB(cb->skb).portid,
203 seq: cb->nlh->nlmsg_seq,
204 NLM_F_MULTI, sk_ino) < 0) {
205 spin_unlock(lock: &net->unx.table.locks[slot]);
206 goto done;
207 }
208next:
209 num++;
210 }
211 spin_unlock(lock: &net->unx.table.locks[slot]);
212 }
213done:
214 cb->args[0] = slot;
215 cb->args[1] = num;
216
217 return skb->len;
218}
219
220static struct sock *unix_lookup_by_ino(struct net *net, unsigned int ino)
221{
222 struct sock *sk;
223 int i;
224
225 for (i = 0; i < UNIX_HASH_SIZE; i++) {
226 spin_lock(lock: &net->unx.table.locks[i]);
227 sk_for_each(sk, &net->unx.table.buckets[i]) {
228 if (ino == sock_i_ino(sk)) {
229 sock_hold(sk);
230 spin_unlock(lock: &net->unx.table.locks[i]);
231 return sk;
232 }
233 }
234 spin_unlock(lock: &net->unx.table.locks[i]);
235 }
236 return NULL;
237}
238
239static int unix_diag_get_exact(struct sk_buff *in_skb,
240 const struct nlmsghdr *nlh,
241 struct unix_diag_req *req)
242{
243 struct net *net = sock_net(sk: in_skb->sk);
244 unsigned int extra_len;
245 struct sk_buff *rep;
246 struct sock *sk;
247 int err;
248
249 err = -EINVAL;
250 if (req->udiag_ino == 0)
251 goto out_nosk;
252
253 sk = unix_lookup_by_ino(net, ino: req->udiag_ino);
254 err = -ENOENT;
255 if (sk == NULL)
256 goto out_nosk;
257
258 err = sock_diag_check_cookie(sk, cookie: req->udiag_cookie);
259 if (err)
260 goto out;
261
262 extra_len = 256;
263again:
264 err = -ENOMEM;
265 rep = nlmsg_new(payload: sizeof(struct unix_diag_msg) + extra_len, GFP_KERNEL);
266 if (!rep)
267 goto out;
268
269 err = sk_diag_fill(sk, skb: rep, req, user_ns: sk_user_ns(NETLINK_CB(in_skb).sk),
270 NETLINK_CB(in_skb).portid,
271 seq: nlh->nlmsg_seq, flags: 0, sk_ino: req->udiag_ino);
272 if (err < 0) {
273 nlmsg_free(skb: rep);
274 extra_len += 256;
275 if (extra_len >= PAGE_SIZE)
276 goto out;
277
278 goto again;
279 }
280 err = nlmsg_unicast(sk: net->diag_nlsk, skb: rep, NETLINK_CB(in_skb).portid);
281
282out:
283 if (sk)
284 sock_put(sk);
285out_nosk:
286 return err;
287}
288
289static int unix_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
290{
291 int hdrlen = sizeof(struct unix_diag_req);
292
293 if (nlmsg_len(nlh: h) < hdrlen)
294 return -EINVAL;
295
296 if (h->nlmsg_flags & NLM_F_DUMP) {
297 struct netlink_dump_control c = {
298 .dump = unix_diag_dump,
299 };
300 return netlink_dump_start(ssk: sock_net(sk: skb->sk)->diag_nlsk, skb, nlh: h, control: &c);
301 } else
302 return unix_diag_get_exact(in_skb: skb, nlh: h, req: nlmsg_data(nlh: h));
303}
304
305static const struct sock_diag_handler unix_diag_handler = {
306 .owner = THIS_MODULE,
307 .family = AF_UNIX,
308 .dump = unix_diag_handler_dump,
309};
310
311static int __init unix_diag_init(void)
312{
313 return sock_diag_register(h: &unix_diag_handler);
314}
315
316static void __exit unix_diag_exit(void)
317{
318 sock_diag_unregister(h: &unix_diag_handler);
319}
320
321module_init(unix_diag_init);
322module_exit(unix_diag_exit);
323MODULE_LICENSE("GPL");
324MODULE_DESCRIPTION("UNIX socket monitoring via SOCK_DIAG");
325MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 1 /* AF_LOCAL */);
326

source code of linux/net/unix/diag.c