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 (sk->sk_net != &init_net)
  73                 return -ENOPROTOOPT;
  74
  75         if (mutex_lock_interruptible(&nf_sockopt_mutex) != 0)
  76                 return -EINTR;
  77
  78         list_for_each(i, &nf_sockopts) {
  79                 ops = (struct nf_sockopt_ops *)i;
  80                 if (ops->pf == pf) {
  81                         if (!try_module_get(ops->owner))
  82                                 goto out_nosup;
  83                         if (get) {
  84                                 if (val >= ops->get_optmin
  85                                     && val < ops->get_optmax) {
  86                                         mutex_unlock(&nf_sockopt_mutex);
  87                                         ret = ops->get(sk, val, opt, len);
  88                                         goto out;
  89                                 }
  90                         } else {
  91                                 if (val >= ops->set_optmin
  92                                     && val < ops->set_optmax) {
  93                                         mutex_unlock(&nf_sockopt_mutex);
  94                                         ret = ops->set(sk, val, opt, *len);
  95                                         goto out;
  96                                 }
  97                         }
  98                         module_put(ops->owner);
  99                 }
 100         }
 101  out_nosup:
 102         mutex_unlock(&nf_sockopt_mutex);
 103         return -ENOPROTOOPT;
 104
 105  out:
 106         module_put(ops->owner);
 107         return ret;
 108 }
 109
 110 int nf_setsockopt(struct sock *sk, int pf, int val, char __user *opt,
 111                   int len)
 112 {
 113         return nf_sockopt(sk, pf, val, opt, &len, 0);
 114 }
 115 EXPORT_SYMBOL(nf_setsockopt);
 116
 117 int nf_getsockopt(struct sock *sk, int pf, int val, char __user *opt, int *len)
 118 {
 119         return nf_sockopt(sk, pf, val, opt, len, 1);
 120 }
 121 EXPORT_SYMBOL(nf_getsockopt);
 122
 123 #ifdef CONFIG_COMPAT
 124 static int compat_nf_sockopt(struct sock *sk, int pf, int val,
 125                              char __user *opt, int *len, int get)
 126 {
 127         struct list_head *i;
 128         struct nf_sockopt_ops *ops;
 129         int ret;
 130
 131         if (sk->sk_net != &init_net)
 132                 return -ENOPROTOOPT;
 133
 134
 135         if (mutex_lock_interruptible(&nf_sockopt_mutex) != 0)
 136                 return -EINTR;
 137
 138         list_for_each(i, &nf_sockopts) {
 139                 ops = (struct nf_sockopt_ops *)i;
 140                 if (ops->pf == pf) {
 141                         if (!try_module_get(ops->owner))
 142                                 goto out_nosup;
 143
 144                         if (get) {
 145                                 if (val >= ops->get_optmin
 146                                     && val < ops->get_optmax) {
 147                                         mutex_unlock(&nf_sockopt_mutex);
 148                                         if (ops->compat_get)
 149                                                 ret = ops->compat_get(sk,
 150                                                         val, opt, len);
 151                                         else
 152                                                 ret = ops->get(sk,
 153                                                         val, opt, len);
 154                                         goto out;
 155                                 }
 156                         } else {
 157                                 if (val >= ops->set_optmin
 158                                     && val < ops->set_optmax) {
 159                                         mutex_unlock(&nf_sockopt_mutex);
 160                                         if (ops->compat_set)
 161                                                 ret = ops->compat_set(sk,
 162                                                         val, opt, *len);
 163                                         else
 164                                                 ret = ops->set(sk,
 165                                                         val, opt, *len);
 166                                         goto out;
 167                                 }
 168                         }
 169                         module_put(ops->owner);
 170                 }
 171         }
 172  out_nosup:
 173         mutex_unlock(&nf_sockopt_mutex);
 174         return -ENOPROTOOPT;
 175
 176  out:
 177         module_put(ops->owner);
 178         return ret;
 179 }
 180
 181 int compat_nf_setsockopt(struct sock *sk, int pf,
 182                 int val, char __user *opt, int len)
 183 {
 184         return compat_nf_sockopt(sk, pf, val, opt, &len, 0);
 185 }
 186 EXPORT_SYMBOL(compat_nf_setsockopt);
 187
 188 int compat_nf_getsockopt(struct sock *sk, int pf,
 189                 int val, char __user *opt, int *len)
 190 {
 191         return compat_nf_sockopt(sk, pf, val, opt, len, 1);
 192 }
 193 EXPORT_SYMBOL(compat_nf_getsockopt);
 194 #endif