1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/init.h>
4 #include <linux/module.h>
5 #include <linux/skbuff.h>
6 #include <linux/netfilter.h>
7 #include <linux/mutex.h>
8 #include <net/sock.h>
9
10 #include "nf_internals.h"
11
12 /* Sockopts only registered and called from user context, so
13 net locking would be overkill. Also, [gs]etsockopt calls may
14 sleep. */
15 static DEFINE_MUTEX(nf_sockopt_mutex);
16 static LIST_HEAD(nf_sockopts);
17
18 /* Do exclusive ranges overlap? */
overlap(int min1,int max1,int min2,int max2)19 static inline int overlap(int min1, int max1, int min2, int max2)
20 {
21 return max1 > min2 && min1 < max2;
22 }
23
24 /* Functions to register sockopt ranges (exclusive). */
nf_register_sockopt(struct nf_sockopt_ops * reg)25 int nf_register_sockopt(struct nf_sockopt_ops *reg)
26 {
27 struct nf_sockopt_ops *ops;
28 int ret = 0;
29
30 mutex_lock(&nf_sockopt_mutex);
31 list_for_each_entry(ops, &nf_sockopts, list) {
32 if (ops->pf == reg->pf
33 && (overlap(ops->set_optmin, ops->set_optmax,
34 reg->set_optmin, reg->set_optmax)
35 || overlap(ops->get_optmin, ops->get_optmax,
36 reg->get_optmin, reg->get_optmax))) {
37 pr_debug("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
38 ops->set_optmin, ops->set_optmax,
39 ops->get_optmin, ops->get_optmax,
40 reg->set_optmin, reg->set_optmax,
41 reg->get_optmin, reg->get_optmax);
42 ret = -EBUSY;
43 goto out;
44 }
45 }
46
47 list_add(®->list, &nf_sockopts);
48 out:
49 mutex_unlock(&nf_sockopt_mutex);
50 return ret;
51 }
52 EXPORT_SYMBOL(nf_register_sockopt);
53
nf_unregister_sockopt(struct nf_sockopt_ops * reg)54 void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
55 {
56 mutex_lock(&nf_sockopt_mutex);
57 list_del(®->list);
58 mutex_unlock(&nf_sockopt_mutex);
59 }
60 EXPORT_SYMBOL(nf_unregister_sockopt);
61
nf_sockopt_find(struct sock * sk,u_int8_t pf,int val,int get)62 static struct nf_sockopt_ops *nf_sockopt_find(struct sock *sk, u_int8_t pf,
63 int val, int get)
64 {
65 struct nf_sockopt_ops *ops;
66
67 mutex_lock(&nf_sockopt_mutex);
68 list_for_each_entry(ops, &nf_sockopts, list) {
69 if (ops->pf == pf) {
70 if (!try_module_get(ops->owner))
71 goto out_nosup;
72
73 if (get) {
74 if (val >= ops->get_optmin &&
75 val < ops->get_optmax)
76 goto out;
77 } else {
78 if (val >= ops->set_optmin &&
79 val < ops->set_optmax)
80 goto out;
81 }
82 module_put(ops->owner);
83 }
84 }
85 out_nosup:
86 ops = ERR_PTR(-ENOPROTOOPT);
87 out:
88 mutex_unlock(&nf_sockopt_mutex);
89 return ops;
90 }
91
nf_setsockopt(struct sock * sk,u_int8_t pf,int val,sockptr_t opt,unsigned int len)92 int nf_setsockopt(struct sock *sk, u_int8_t pf, int val, sockptr_t opt,
93 unsigned int len)
94 {
95 struct nf_sockopt_ops *ops;
96 int ret;
97
98 ops = nf_sockopt_find(sk, pf, val, 0);
99 if (IS_ERR(ops))
100 return PTR_ERR(ops);
101 ret = ops->set(sk, val, opt, len);
102 module_put(ops->owner);
103 return ret;
104 }
105 EXPORT_SYMBOL(nf_setsockopt);
106
nf_getsockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,int * len)107 int nf_getsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
108 int *len)
109 {
110 struct nf_sockopt_ops *ops;
111 int ret;
112
113 ops = nf_sockopt_find(sk, pf, val, 1);
114 if (IS_ERR(ops))
115 return PTR_ERR(ops);
116 ret = ops->get(sk, val, opt, len);
117 module_put(ops->owner);
118 return ret;
119 }
120 EXPORT_SYMBOL(nf_getsockopt);
121