1 #include <linux/kernel.h>
2 #include <linux/init.h>
3 #include <linux/module.h>
4 #include <linux/skbuff.h>
5 #include <linux/netfilter.h>
6 #include <linux/mutex.h>
7 #include <net/sock.h>
8
9 #include "nf_internals.h"
10
11 /* Sockopts only registered and called from user context, so
12 net locking would be overkill. Also, [gs]etsockopt calls may
13 sleep. */
14 static DEFINE_MUTEX(nf_sockopt_mutex);
15 static LIST_HEAD(nf_sockopts);
16
17 /* Do exclusive ranges overlap? */
overlap(int min1,int max1,int min2,int max2)18 static inline int overlap(int min1, int max1, int min2, int max2)
19 {
20 return max1 > min2 && min1 < max2;
21 }
22
23 /* Functions to register sockopt ranges (exclusive). */
nf_register_sockopt(struct nf_sockopt_ops * reg)24 int nf_register_sockopt(struct nf_sockopt_ops *reg)
25 {
26 struct nf_sockopt_ops *ops;
27 int ret = 0;
28
29 if (mutex_lock_interruptible(&nf_sockopt_mutex) != 0)
30 return -EINTR;
31
32 list_for_each_entry(ops, &nf_sockopts, list) {
33 if (ops->pf == reg->pf
34 && (overlap(ops->set_optmin, ops->set_optmax,
35 reg->set_optmin, reg->set_optmax)
36 || overlap(ops->get_optmin, ops->get_optmax,
37 reg->get_optmin, reg->get_optmax))) {
38 NFDEBUG("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
39 ops->set_optmin, ops->set_optmax,
40 ops->get_optmin, ops->get_optmax,
41 reg->set_optmin, reg->set_optmax,
42 reg->get_optmin, reg->get_optmax);
43 ret = -EBUSY;
44 goto out;
45 }
46 }
47
48 list_add(®->list, &nf_sockopts);
49 out:
50 mutex_unlock(&nf_sockopt_mutex);
51 return ret;
52 }
53 EXPORT_SYMBOL(nf_register_sockopt);
54
nf_unregister_sockopt(struct nf_sockopt_ops * reg)55 void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
56 {
57 mutex_lock(&nf_sockopt_mutex);
58 list_del(®->list);
59 mutex_unlock(&nf_sockopt_mutex);
60 }
61 EXPORT_SYMBOL(nf_unregister_sockopt);
62
nf_sockopt_find(struct sock * sk,u_int8_t pf,int val,int get)63 static struct nf_sockopt_ops *nf_sockopt_find(struct sock *sk, u_int8_t pf,
64 int val, int get)
65 {
66 struct nf_sockopt_ops *ops;
67
68 if (mutex_lock_interruptible(&nf_sockopt_mutex) != 0)
69 return ERR_PTR(-EINTR);
70
71 list_for_each_entry(ops, &nf_sockopts, list) {
72 if (ops->pf == pf) {
73 if (!try_module_get(ops->owner))
74 goto out_nosup;
75
76 if (get) {
77 if (val >= ops->get_optmin &&
78 val < ops->get_optmax)
79 goto out;
80 } else {
81 if (val >= ops->set_optmin &&
82 val < ops->set_optmax)
83 goto out;
84 }
85 module_put(ops->owner);
86 }
87 }
88 out_nosup:
89 ops = ERR_PTR(-ENOPROTOOPT);
90 out:
91 mutex_unlock(&nf_sockopt_mutex);
92 return ops;
93 }
94
95 /* Call get/setsockopt() */
nf_sockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,int * len,int get)96 static int nf_sockopt(struct sock *sk, u_int8_t pf, int val,
97 char __user *opt, int *len, int get)
98 {
99 struct nf_sockopt_ops *ops;
100 int ret;
101
102 ops = nf_sockopt_find(sk, pf, val, get);
103 if (IS_ERR(ops))
104 return PTR_ERR(ops);
105
106 if (get)
107 ret = ops->get(sk, val, opt, len);
108 else
109 ret = ops->set(sk, val, opt, *len);
110
111 module_put(ops->owner);
112 return ret;
113 }
114
nf_setsockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,unsigned int len)115 int nf_setsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
116 unsigned int len)
117 {
118 return nf_sockopt(sk, pf, val, opt, &len, 0);
119 }
120 EXPORT_SYMBOL(nf_setsockopt);
121
nf_getsockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,int * len)122 int nf_getsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
123 int *len)
124 {
125 return nf_sockopt(sk, pf, val, opt, len, 1);
126 }
127 EXPORT_SYMBOL(nf_getsockopt);
128
129 #ifdef CONFIG_COMPAT
compat_nf_sockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,int * len,int get)130 static int compat_nf_sockopt(struct sock *sk, u_int8_t pf, int val,
131 char __user *opt, int *len, int get)
132 {
133 struct nf_sockopt_ops *ops;
134 int ret;
135
136 ops = nf_sockopt_find(sk, pf, val, get);
137 if (IS_ERR(ops))
138 return PTR_ERR(ops);
139
140 if (get) {
141 if (ops->compat_get)
142 ret = ops->compat_get(sk, val, opt, len);
143 else
144 ret = ops->get(sk, val, opt, len);
145 } else {
146 if (ops->compat_set)
147 ret = ops->compat_set(sk, val, opt, *len);
148 else
149 ret = ops->set(sk, val, opt, *len);
150 }
151
152 module_put(ops->owner);
153 return ret;
154 }
155
compat_nf_setsockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,unsigned int len)156 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf,
157 int val, char __user *opt, unsigned int len)
158 {
159 return compat_nf_sockopt(sk, pf, val, opt, &len, 0);
160 }
161 EXPORT_SYMBOL(compat_nf_setsockopt);
162
compat_nf_getsockopt(struct sock * sk,u_int8_t pf,int val,char __user * opt,int * len)163 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf,
164 int val, char __user *opt, int *len)
165 {
166 return compat_nf_sockopt(sk, pf, val, opt, len, 1);
167 }
168 EXPORT_SYMBOL(compat_nf_getsockopt);
169 #endif
170