| 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 nf_sockopt_ops *ops; |
| 27 | int ret = 0; |
| 28 | |
| 29 | mutex_lock(&nf_sockopt_mutex); |
| 30 | list_for_each_entry(ops, &nf_sockopts, list) { |
| 31 | if (ops->pf == reg->pf |
| 32 | && (overlap(ops->set_optmin, ops->set_optmax, |
| 33 | reg->set_optmin, reg->set_optmax) |
| 34 | || overlap(ops->get_optmin, ops->get_optmax, |
| 35 | reg->get_optmin, reg->get_optmax))) { |
| 36 | NFDEBUG("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n", |
| 37 | ops->set_optmin, ops->set_optmax, |
| 38 | ops->get_optmin, ops->get_optmax, |
| 39 | reg->set_optmin, reg->set_optmax, |
| 40 | reg->get_optmin, reg->get_optmax); |
| 41 | ret = -EBUSY; |
| 42 | goto out; |
| 43 | } |
| 44 | } |
| 45 | |
| 46 | list_add(®->list, &nf_sockopts); |
| 47 | out: |
| 48 | mutex_unlock(&nf_sockopt_mutex); |
| 49 | return ret; |
| 50 | } |
| 51 | EXPORT_SYMBOL(nf_register_sockopt); |
| 52 | |
| 53 | void nf_unregister_sockopt(struct nf_sockopt_ops *reg) |
| 54 | { |
| 55 | mutex_lock(&nf_sockopt_mutex); |
| 56 | list_del(®->list); |
| 57 | mutex_unlock(&nf_sockopt_mutex); |
| 58 | } |
| 59 | EXPORT_SYMBOL(nf_unregister_sockopt); |
| 60 | |
| 61 | static struct nf_sockopt_ops *nf_sockopt_find(struct sock *sk, u_int8_t pf, |
| 62 | int val, int get) |
| 63 | { |
| 64 | struct nf_sockopt_ops *ops; |
| 65 | |
| 66 | mutex_lock(&nf_sockopt_mutex); |
| 67 | list_for_each_entry(ops, &nf_sockopts, list) { |
| 68 | if (ops->pf == pf) { |
| 69 | if (!try_module_get(ops->owner)) |
| 70 | goto out_nosup; |
| 71 | |
| 72 | if (get) { |
| 73 | if (val >= ops->get_optmin && |
| 74 | val < ops->get_optmax) |
| 75 | goto out; |
| 76 | } else { |
| 77 | if (val >= ops->set_optmin && |
| 78 | val < ops->set_optmax) |
| 79 | goto out; |
| 80 | } |
| 81 | module_put(ops->owner); |
| 82 | } |
| 83 | } |
| 84 | out_nosup: |
| 85 | ops = ERR_PTR(-ENOPROTOOPT); |
| 86 | out: |
| 87 | mutex_unlock(&nf_sockopt_mutex); |
| 88 | return ops; |
| 89 | } |
| 90 | |
| 91 | /* Call get/setsockopt() */ |
| 92 | static int nf_sockopt(struct sock *sk, u_int8_t pf, int val, |
| 93 | char __user *opt, int *len, int get) |
| 94 | { |
| 95 | struct nf_sockopt_ops *ops; |
| 96 | int ret; |
| 97 | |
| 98 | ops = nf_sockopt_find(sk, pf, val, get); |
| 99 | if (IS_ERR(ops)) |
| 100 | return PTR_ERR(ops); |
| 101 | |
| 102 | if (get) |
| 103 | ret = ops->get(sk, val, opt, len); |
| 104 | else |
| 105 | ret = ops->set(sk, val, opt, *len); |
| 106 | |
| 107 | module_put(ops->owner); |
| 108 | return ret; |
| 109 | } |
| 110 | |
| 111 | int nf_setsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt, |
| 112 | unsigned int len) |
| 113 | { |
| 114 | return nf_sockopt(sk, pf, val, opt, &len, 0); |
| 115 | } |
| 116 | EXPORT_SYMBOL(nf_setsockopt); |
| 117 | |
| 118 | int nf_getsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt, |
| 119 | int *len) |
| 120 | { |
| 121 | return nf_sockopt(sk, pf, val, opt, len, 1); |
| 122 | } |
| 123 | EXPORT_SYMBOL(nf_getsockopt); |
| 124 | |
| 125 | #ifdef CONFIG_COMPAT |
| 126 | static int compat_nf_sockopt(struct sock *sk, u_int8_t pf, int val, |
| 127 | char __user *opt, int *len, int get) |
| 128 | { |
| 129 | struct nf_sockopt_ops *ops; |
| 130 | int ret; |
| 131 | |
| 132 | ops = nf_sockopt_find(sk, pf, val, get); |
| 133 | if (IS_ERR(ops)) |
| 134 | return PTR_ERR(ops); |
| 135 | |
| 136 | if (get) { |
| 137 | if (ops->compat_get) |
| 138 | ret = ops->compat_get(sk, val, opt, len); |
| 139 | else |
| 140 | ret = ops->get(sk, val, opt, len); |
| 141 | } else { |
| 142 | if (ops->compat_set) |
| 143 | ret = ops->compat_set(sk, val, opt, *len); |
| 144 | else |
| 145 | ret = ops->set(sk, val, opt, *len); |
| 146 | } |
| 147 | |
| 148 | module_put(ops->owner); |
| 149 | return ret; |
| 150 | } |
| 151 | |
| 152 | int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, |
| 153 | int val, char __user *opt, unsigned int len) |
| 154 | { |
| 155 | return compat_nf_sockopt(sk, pf, val, opt, &len, 0); |
| 156 | } |
| 157 | EXPORT_SYMBOL(compat_nf_setsockopt); |
| 158 | |
| 159 | int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, |
| 160 | int val, char __user *opt, int *len) |
| 161 | { |
| 162 | return compat_nf_sockopt(sk, pf, val, opt, len, 1); |
| 163 | } |
| 164 | EXPORT_SYMBOL(compat_nf_getsockopt); |
| 165 | #endif |