1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/module.h>
3
4 #include <net/sock.h>
5 #include <linux/netlink.h>
6 #include <linux/sock_diag.h>
7 #include <linux/netlink_diag.h>
8 #include <linux/rhashtable.h>
9
10 #include "af_netlink.h"
11
sk_diag_dump_groups(struct sock * sk,struct sk_buff * nlskb)12 static int sk_diag_dump_groups(struct sock *sk, struct sk_buff *nlskb)
13 {
14 struct netlink_sock *nlk = nlk_sk(sk);
15 unsigned long *groups;
16 unsigned int ngroups;
17
18 /* Hashed sockets are dumped from the rhashtable walk, which only
19 * holds rcu_read_lock(), while netlink_realloc_groups() can replace
20 * nlk->groups and nlk->ngroups at any time.
21 *
22 * Read nlk->ngroups first : this pairs with smp_store_release()
23 * from netlink_realloc_groups(), so that we can not use the new
24 * (bigger) size with the old (smaller) buffer. The old buffer is
25 * freed after an RCU grace period.
26 */
27 ngroups = smp_load_acquire(&nlk->ngroups);
28 groups = READ_ONCE(nlk->groups);
29 if (!groups)
30 return 0;
31
32 return nla_put(nlskb, NETLINK_DIAG_GROUPS, NLGRPSZ(ngroups), groups);
33 }
34
sk_diag_put_flags(struct sock * sk,struct sk_buff * skb)35 static int sk_diag_put_flags(struct sock *sk, struct sk_buff *skb)
36 {
37 struct netlink_sock *nlk = nlk_sk(sk);
38 u32 flags = 0;
39
40 if (nlk->cb_running)
41 flags |= NDIAG_FLAG_CB_RUNNING;
42 if (nlk_test_bit(RECV_PKTINFO, sk))
43 flags |= NDIAG_FLAG_PKTINFO;
44 if (nlk_test_bit(BROADCAST_SEND_ERROR, sk))
45 flags |= NDIAG_FLAG_BROADCAST_ERROR;
46 if (nlk_test_bit(RECV_NO_ENOBUFS, sk))
47 flags |= NDIAG_FLAG_NO_ENOBUFS;
48 if (nlk_test_bit(LISTEN_ALL_NSID, sk))
49 flags |= NDIAG_FLAG_LISTEN_ALL_NSID;
50 if (nlk_test_bit(CAP_ACK, sk))
51 flags |= NDIAG_FLAG_CAP_ACK;
52
53 return nla_put_u32(skb, NETLINK_DIAG_FLAGS, flags);
54 }
55
sk_diag_fill(struct sock * sk,struct sk_buff * skb,struct netlink_diag_req * req,u32 portid,u32 seq,u32 flags,u64 sk_ino)56 static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
57 struct netlink_diag_req *req,
58 u32 portid, u32 seq, u32 flags, u64 sk_ino)
59 {
60 struct nlmsghdr *nlh;
61 struct netlink_diag_msg *rep;
62 struct netlink_sock *nlk = nlk_sk(sk);
63
64 nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
65 flags);
66 if (!nlh)
67 return -EMSGSIZE;
68
69 rep = nlmsg_data(nlh);
70 rep->ndiag_family = AF_NETLINK;
71 rep->ndiag_type = sk->sk_type;
72 rep->ndiag_protocol = sk->sk_protocol;
73 rep->ndiag_state = sk->sk_state;
74
75 rep->ndiag_ino = sk_ino;
76 rep->ndiag_portid = nlk->portid;
77 rep->ndiag_dst_portid = nlk->dst_portid;
78 rep->ndiag_dst_group = nlk->dst_group;
79 sock_diag_save_cookie(sk, rep->ndiag_cookie);
80
81 if ((req->ndiag_show & NDIAG_SHOW_GROUPS) &&
82 sk_diag_dump_groups(sk, skb))
83 goto out_nlmsg_trim;
84
85 if ((req->ndiag_show & NDIAG_SHOW_MEMINFO) &&
86 sock_diag_put_meminfo(sk, skb, NETLINK_DIAG_MEMINFO))
87 goto out_nlmsg_trim;
88
89 if ((req->ndiag_show & NDIAG_SHOW_FLAGS) &&
90 sk_diag_put_flags(sk, skb))
91 goto out_nlmsg_trim;
92
93 nlmsg_end(skb, nlh);
94 return 0;
95
96 out_nlmsg_trim:
97 nlmsg_cancel(skb, nlh);
98 return -EMSGSIZE;
99 }
100
__netlink_diag_dump(struct sk_buff * skb,struct netlink_callback * cb,int protocol,int s_num)101 static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
102 int protocol, int s_num)
103 {
104 struct rhashtable_iter *hti = (void *)cb->args[2];
105 struct netlink_table *tbl = &nl_table[protocol];
106 struct net *net = sock_net(skb->sk);
107 struct netlink_diag_req *req;
108 struct netlink_sock *nlsk;
109 unsigned long flags;
110 struct sock *sk;
111 int num = 2;
112 int ret = 0;
113
114 req = nlmsg_data(cb->nlh);
115
116 if (s_num > 1)
117 goto mc_list;
118
119 num--;
120
121 if (!hti) {
122 hti = kmalloc_obj(*hti);
123 if (!hti)
124 return -ENOMEM;
125
126 cb->args[2] = (long)hti;
127 }
128
129 if (!s_num)
130 rhashtable_walk_enter(&tbl->hash, hti);
131
132 rhashtable_walk_start(hti);
133
134 while ((nlsk = rhashtable_walk_next(hti))) {
135 if (IS_ERR(nlsk)) {
136 ret = PTR_ERR(nlsk);
137 if (ret == -EAGAIN) {
138 ret = 0;
139 continue;
140 }
141 break;
142 }
143
144 sk = (struct sock *)nlsk;
145
146 if (!net_eq(sock_net(sk), net))
147 continue;
148
149 if (sk_diag_fill(sk, skb, req,
150 NETLINK_CB(cb->skb).portid,
151 cb->nlh->nlmsg_seq,
152 NLM_F_MULTI,
153 sock_i_ino(sk)) < 0) {
154 ret = 1;
155 break;
156 }
157 }
158
159 rhashtable_walk_stop(hti);
160
161 if (ret)
162 goto done;
163
164 rhashtable_walk_exit(hti);
165 num++;
166
167 mc_list:
168 read_lock_irqsave(&nl_table_lock, flags);
169 sk_for_each_bound(sk, &tbl->mc_list) {
170 if (sk_hashed(sk))
171 continue;
172 if (!net_eq(sock_net(sk), net))
173 continue;
174 if (num < s_num) {
175 num++;
176 continue;
177 }
178
179 if (sk_diag_fill(sk, skb, req,
180 NETLINK_CB(cb->skb).portid,
181 cb->nlh->nlmsg_seq,
182 NLM_F_MULTI,
183 sock_i_ino(sk)) < 0) {
184 ret = 1;
185 break;
186 }
187 num++;
188 }
189 read_unlock_irqrestore(&nl_table_lock, flags);
190
191 done:
192 cb->args[0] = num;
193
194 return ret;
195 }
196
netlink_diag_dump(struct sk_buff * skb,struct netlink_callback * cb)197 static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
198 {
199 struct netlink_diag_req *req;
200 int s_num = cb->args[0];
201 int err = 0;
202
203 req = nlmsg_data(cb->nlh);
204
205 if (req->sdiag_protocol == NDIAG_PROTO_ALL) {
206 int i;
207
208 for (i = cb->args[1]; i < MAX_LINKS; i++) {
209 err = __netlink_diag_dump(skb, cb, i, s_num);
210 if (err)
211 break;
212 s_num = 0;
213 }
214 cb->args[1] = i;
215 } else {
216 if (req->sdiag_protocol >= MAX_LINKS)
217 return -ENOENT;
218
219 err = __netlink_diag_dump(skb, cb, req->sdiag_protocol, s_num);
220 }
221
222 return err <= 0 ? err : skb->len;
223 }
224
netlink_diag_dump_done(struct netlink_callback * cb)225 static int netlink_diag_dump_done(struct netlink_callback *cb)
226 {
227 struct rhashtable_iter *hti = (void *)cb->args[2];
228
229 if (cb->args[0] == 1)
230 rhashtable_walk_exit(hti);
231
232 kfree(hti);
233
234 return 0;
235 }
236
netlink_diag_handler_dump(struct sk_buff * skb,struct nlmsghdr * h)237 static int netlink_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
238 {
239 int hdrlen = sizeof(struct netlink_diag_req);
240 struct net *net = sock_net(skb->sk);
241
242 if (nlmsg_len(h) < hdrlen)
243 return -EINVAL;
244
245 if (h->nlmsg_flags & NLM_F_DUMP) {
246 struct netlink_dump_control c = {
247 .dump = netlink_diag_dump,
248 .done = netlink_diag_dump_done,
249 };
250 return netlink_dump_start(net->diag_nlsk, skb, h, &c);
251 } else
252 return -EOPNOTSUPP;
253 }
254
255 static const struct sock_diag_handler netlink_diag_handler = {
256 .owner = THIS_MODULE,
257 .family = AF_NETLINK,
258 .dump = netlink_diag_handler_dump,
259 };
260
netlink_diag_init(void)261 static int __init netlink_diag_init(void)
262 {
263 return sock_diag_register(&netlink_diag_handler);
264 }
265
netlink_diag_exit(void)266 static void __exit netlink_diag_exit(void)
267 {
268 sock_diag_unregister(&netlink_diag_handler);
269 }
270
271 module_init(netlink_diag_init);
272 module_exit(netlink_diag_exit);
273 MODULE_DESCRIPTION("Netlink-based socket monitoring/diagnostic interface (sock_diag)");
274 MODULE_LICENSE("GPL");
275 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 16 /* AF_NETLINK */);
276