net/netfilter/nf_sockopt.c

   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? */
  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). */
  24 int nf_register_sockopt(struct nf_sockopt_ops *reg)
  25 {
  26         struct list_head *i;
  27         int ret = 0;
  28
  29         if (mutex_lock_interruptible(&nf_sockopt_mutex) != 0)
  30                 return -EINTR;
  31
  32         list_for_each(i, &nf_sockopts) {
  33                 struct nf_sockopt_ops *ops = (struct nf_sockopt_ops *)i;
  34                 if (ops->pf == reg->pf
  35                     && (overlap(ops->set_optmin, ops->set_optmax,
  36                                 reg->set_optmin, reg->set_optmax)
  37                         || overlap(ops->get_optmin, ops->get_optmax,
  38                                    reg->get_optmin, reg->get_optmax))) {
  39                         NFDEBUG("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
  40                                 ops->set_optmin, ops->set_optmax,
  41                                 ops->get_optmin, ops->get_optmax,
  42                                 reg->set_optmin, reg->set_optmax,
  43                                 reg->get_optmin, reg->get_optmax);
  44                         ret = -EBUSY;
  45                         goto out;
  46                 }
  47         }
  48
  49         list_add(&reg->list, &nf_sockopts);
  50 out:
  51         mutex_unlock(&nf_sockopt_mutex);
  52         return ret;
  53 }
  54 EXPORT_SYMBOL(nf_register_sockopt);
  55
  56 void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
  57 {
  58         mutex_lock(&nf_sockopt_mutex);
  59         list_del(&reg->list);
  60         mutex_unlock(&nf_sockopt_mutex);
  61 }
  62 EXPORT_SYMBOL(nf_unregister_sockopt);
  63
  64 /* Call get/setsockopt() */
  65 static int nf_sockopt(struct sock *sk, int pf, int val,
  66                       char __user *opt, int *len, int get)
  67 {
  68         struct list_head *i;
  69         struct nf_sockopt_ops *ops;
  70         int ret;
  71
  72         if (mutex_lock_interruptible(&nf_sockopt_mutex) != 0)
  73                 return -EINTR;
  74
  75         list_for_each(i, &nf_sockopts) {
  76                 ops = (struct nf_sockopt_ops *)i;
  77                 if (ops->pf == pf) {
  78                         if (!try_module_get(ops->owner))
  79                                 goto out_nosup;
  80                         if (get) {
  81                                 if (val >= ops->get_optmin
  82                                     && val < ops->get_optmax) {
  83                                         mutex_unlock(&nf_sockopt_mutex);
  84                                         ret = ops->get(sk, val, opt, len);
  85                                         goto out;
  86                                 }
  87                         } else {
  88                                 if (val >= ops->set_optmin
  89                                     && val < ops->set_optmax) {
  90                                         mutex_unlock(&nf_sockopt_mutex);
  91                                         ret = ops->set(sk, val, opt, *len);
  92                                         goto out;
  93                                 }
  94                         }
  95                         module_put(ops->owner);
  96                 }
  97         }
  98  out_nosup:
  99         mutex_unlock(&nf_sockopt_mutex);
 100         return -ENOPROTOOPT;
 101
 102  out:
 103         module_put(ops->owner);
 104         return ret;
 105 }
 106
 107 int nf_setsockopt(struct sock *sk, int pf, int val, char __user *opt,
 108                   int len)
 109 {
 110         return nf_sockopt(sk, pf, val, opt, &len, 0);
 111 }
 112 EXPORT_SYMBOL(nf_setsockopt);
 113
 114 int nf_getsockopt(struct sock *sk, int pf, int val, char __user *opt, int *len)
 115 {
 116         return nf_sockopt(sk, pf, val, opt, len, 1);
 117 }
 118 EXPORT_SYMBOL(nf_getsockopt);
 119
 120 #ifdef CONFIG_COMPAT
 121 static int compat_nf_sockopt(struct sock *sk, int pf, int val,
 122                              char __user *opt, int *len, int get)
 123 {
 124         struct list_head *i;
 125         struct nf_sockopt_ops *ops;
 126         int ret;
 127
 128         if (mutex_lock_interruptible(&nf_sockopt_mutex) != 0)
 129                 return -EINTR;
 130
 131         list_for_each(i, &nf_sockopts) {
 132                 ops = (struct nf_sockopt_ops *)i;
 133                 if (ops->pf == pf) {
 134                         if (!try_module_get(ops->owner))
 135                                 goto out_nosup;
 136
 137                         if (get) {
 138                                 if (val >= ops->get_optmin
 139                                     && val < ops->get_optmax) {
 140                                         mutex_unlock(&nf_sockopt_mutex);
 141                                         if (ops->compat_get)
 142                                                 ret = ops->compat_get(sk,
 143                                                         val, opt, len);
 144                                         else
 145                                                 ret = ops->get(sk,
 146                                                         val, opt, len);
 147                                         goto out;
 148                                 }
 149                         } else {
 150                                 if (val >= ops->set_optmin
 151                                     && val < ops->set_optmax) {
 152                                         mutex_unlock(&nf_sockopt_mutex);
 153                                         if (ops->compat_set)
 154                                                 ret = ops->compat_set(sk,
 155                                                         val, opt, *len);
 156                                         else
 157                                                 ret = ops->set(sk,
 158                                                         val, opt, *len);
 159                                         goto out;
 160                                 }
 161                         }
 162                         module_put(ops->owner);
 163                 }
 164         }
 165  out_nosup:
 166         mutex_unlock(&nf_sockopt_mutex);
 167         return -ENOPROTOOPT;
 168
 169  out:
 170         module_put(ops->owner);
 171         return ret;
 172 }
 173
 174 int compat_nf_setsockopt(struct sock *sk, int pf,
 175                 int val, char __user *opt, int len)
 176 {
 177         return compat_nf_sockopt(sk, pf, val, opt, &len, 0);
 178 }
 179 EXPORT_SYMBOL(compat_nf_setsockopt);
 180
 181 int compat_nf_getsockopt(struct sock *sk, int pf,
 182                 int val, char __user *opt, int *len)
 183 {
 184         return compat_nf_sockopt(sk, pf, val, opt, len, 1);
 185 }
 186 EXPORT_SYMBOL(compat_nf_getsockopt);
 187 #endif