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
92 /* Call get/setsockopt() */
nf_sockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,int * len,int get)93 static int nf_sockopt(struct sock *sk, u_int8_t pf, int val,
94 char __user *opt, int *len, int get)
95 {
96 struct nf_sockopt_ops *ops;
97 int ret;
98
99 ops = nf_sockopt_find(sk, pf, val, get);
100 if (IS_ERR(ops))
101 return PTR_ERR(ops);
102
103 if (get)
104 ret = ops->get(sk, val, opt, len);
105 else
106 ret = ops->set(sk, val, opt, *len);
107
108 module_put(ops->owner);
109 return ret;
110 }
111
nf_setsockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,unsigned int len)112 int nf_setsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
113 unsigned int len)
114 {
115 return nf_sockopt(sk, pf, val, opt, &len, 0);
116 }
117 EXPORT_SYMBOL(nf_setsockopt);
118
nf_getsockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,int * len)119 int nf_getsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
120 int *len)
121 {
122 return nf_sockopt(sk, pf, val, opt, len, 1);
123 }
124 EXPORT_SYMBOL(nf_getsockopt);
125
126 #ifdef CONFIG_COMPAT
compat_nf_sockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,int * len,int get)127 static int compat_nf_sockopt(struct sock *sk, u_int8_t pf, int val,
128 char __user *opt, int *len, int get)
129 {
130 struct nf_sockopt_ops *ops;
131 int ret;
132
133 ops = nf_sockopt_find(sk, pf, val, get);
134 if (IS_ERR(ops))
135 return PTR_ERR(ops);
136
137 if (get) {
138 if (ops->compat_get)
139 ret = ops->compat_get(sk, val, opt, len);
140 else
141 ret = ops->get(sk, val, opt, len);
142 } else {
143 if (ops->compat_set)
144 ret = ops->compat_set(sk, val, opt, *len);
145 else
146 ret = ops->set(sk, val, opt, *len);
147 }
148
149 module_put(ops->owner);
150 return ret;
151 }
152
compat_nf_setsockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,unsigned int len)153 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf,
154 int val, char __user *opt, unsigned int len)
155 {
156 return compat_nf_sockopt(sk, pf, val, opt, &len, 0);
157 }
158 EXPORT_SYMBOL(compat_nf_setsockopt);
159
compat_nf_getsockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,int * len)160 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf,
161 int val, char __user *opt, int *len)
162 {
163 return compat_nf_sockopt(sk, pf, val, opt, len, 1);
164 }
165 EXPORT_SYMBOL(compat_nf_getsockopt);
166 #endif
167