net/netfilter/nft_chain_filter.c

   1 #include <linux/init.h>
   2 #include <linux/kernel.h>
   3 #include <linux/netdevice.h>
   4 #include <net/net_namespace.h>
   5 #include <net/netfilter/nf_tables.h>
   6 #include <linux/netfilter_ipv4.h>
   7 #include <linux/netfilter_ipv6.h>
   8 #include <linux/netfilter_bridge.h>
   9 #include <linux/netfilter_arp.h>
  10 #include <net/netfilter/nf_tables_ipv4.h>
  11 #include <net/netfilter/nf_tables_ipv6.h>
  12
  13 #ifdef CONFIG_NF_TABLES_IPV4
  14 static unsigned int nft_do_chain_ipv4(void *priv,
  15                                       struct sk_buff *skb,
  16                                       const struct nf_hook_state *state)
  17 {
  18         struct nft_pktinfo pkt;
  19
  20         nft_set_pktinfo(&pkt, skb, state);
  21         nft_set_pktinfo_ipv4(&pkt, skb);
  22
  23         return nft_do_chain(&pkt, priv);
  24 }
  25
  26 static const struct nft_chain_type nft_chain_filter_ipv4 = {
  27         .name           = "filter",
  28         .type           = NFT_CHAIN_T_DEFAULT,
  29         .family         = NFPROTO_IPV4,
  30         .hook_mask      = (1 << NF_INET_LOCAL_IN) |
  31                           (1 << NF_INET_LOCAL_OUT) |
  32                           (1 << NF_INET_FORWARD) |
  33                           (1 << NF_INET_PRE_ROUTING) |
  34                           (1 << NF_INET_POST_ROUTING),
  35         .hooks          = {
  36                 [NF_INET_LOCAL_IN]      = nft_do_chain_ipv4,
  37                 [NF_INET_LOCAL_OUT]     = nft_do_chain_ipv4,
  38                 [NF_INET_FORWARD]       = nft_do_chain_ipv4,
  39                 [NF_INET_PRE_ROUTING]   = nft_do_chain_ipv4,
  40                 [NF_INET_POST_ROUTING]  = nft_do_chain_ipv4,
  41         },
  42 };
  43
  44 static void nft_chain_filter_ipv4_init(void)
  45 {
  46         nft_register_chain_type(&nft_chain_filter_ipv4);
  47 }
  48 static void nft_chain_filter_ipv4_fini(void)
  49 {
  50         nft_unregister_chain_type(&nft_chain_filter_ipv4);
  51 }
  52
  53 #else
  54 static inline void nft_chain_filter_ipv4_init(void) {}
  55 static inline void nft_chain_filter_ipv4_fini(void) {}
  56 #endif /* CONFIG_NF_TABLES_IPV4 */
  57
  58 #ifdef CONFIG_NF_TABLES_ARP
  59 static unsigned int nft_do_chain_arp(void *priv, struct sk_buff *skb,
  60                                      const struct nf_hook_state *state)
  61 {
  62         struct nft_pktinfo pkt;
  63
  64         nft_set_pktinfo(&pkt, skb, state);
  65         nft_set_pktinfo_unspec(&pkt, skb);
  66
  67         return nft_do_chain(&pkt, priv);
  68 }
  69
  70 static const struct nft_chain_type nft_chain_filter_arp = {
  71         .name           = "filter",
  72         .type           = NFT_CHAIN_T_DEFAULT,
  73         .family         = NFPROTO_ARP,
  74         .owner          = THIS_MODULE,
  75         .hook_mask      = (1 << NF_ARP_IN) |
  76                           (1 << NF_ARP_OUT),
  77         .hooks          = {
  78                 [NF_ARP_IN]             = nft_do_chain_arp,
  79                 [NF_ARP_OUT]            = nft_do_chain_arp,
  80         },
  81 };
  82
  83 static void nft_chain_filter_arp_init(void)
  84 {
  85         nft_register_chain_type(&nft_chain_filter_arp);
  86 }
  87
  88 static void nft_chain_filter_arp_fini(void)
  89 {
  90         nft_unregister_chain_type(&nft_chain_filter_arp);
  91 }
  92 #else
  93 static inline void nft_chain_filter_arp_init(void) {}
  94 static inline void nft_chain_filter_arp_fini(void) {}
  95 #endif /* CONFIG_NF_TABLES_ARP */
  96
  97 #ifdef CONFIG_NF_TABLES_IPV6
  98 static unsigned int nft_do_chain_ipv6(void *priv,
  99                                       struct sk_buff *skb,
 100                                       const struct nf_hook_state *state)
 101 {
 102         struct nft_pktinfo pkt;
 103
 104         nft_set_pktinfo(&pkt, skb, state);
 105         nft_set_pktinfo_ipv6(&pkt, skb);
 106
 107         return nft_do_chain(&pkt, priv);
 108 }
 109
 110 static const struct nft_chain_type nft_chain_filter_ipv6 = {
 111         .name           = "filter",
 112         .type           = NFT_CHAIN_T_DEFAULT,
 113         .family         = NFPROTO_IPV6,
 114         .hook_mask      = (1 << NF_INET_LOCAL_IN) |
 115                           (1 << NF_INET_LOCAL_OUT) |
 116                           (1 << NF_INET_FORWARD) |
 117                           (1 << NF_INET_PRE_ROUTING) |
 118                           (1 << NF_INET_POST_ROUTING),
 119         .hooks          = {
 120                 [NF_INET_LOCAL_IN]      = nft_do_chain_ipv6,
 121                 [NF_INET_LOCAL_OUT]     = nft_do_chain_ipv6,
 122                 [NF_INET_FORWARD]       = nft_do_chain_ipv6,
 123                 [NF_INET_PRE_ROUTING]   = nft_do_chain_ipv6,
 124                 [NF_INET_POST_ROUTING]  = nft_do_chain_ipv6,
 125         },
 126 };
 127
 128 static void nft_chain_filter_ipv6_init(void)
 129 {
 130         nft_register_chain_type(&nft_chain_filter_ipv6);
 131 }
 132
 133 static void nft_chain_filter_ipv6_fini(void)
 134 {
 135         nft_unregister_chain_type(&nft_chain_filter_ipv6);
 136 }
 137 #else
 138 static inline void nft_chain_filter_ipv6_init(void) {}
 139 static inline void nft_chain_filter_ipv6_fini(void) {}
 140 #endif /* CONFIG_NF_TABLES_IPV6 */
 141
 142 #ifdef CONFIG_NF_TABLES_INET
 143 static unsigned int nft_do_chain_inet(void *priv, struct sk_buff *skb,
 144                                       const struct nf_hook_state *state)
 145 {
 146         struct nft_pktinfo pkt;
 147
 148         nft_set_pktinfo(&pkt, skb, state);
 149
 150         switch (state->pf) {
 151         case NFPROTO_IPV4:
 152                 nft_set_pktinfo_ipv4(&pkt, skb);
 153                 break;
 154         case NFPROTO_IPV6:
 155                 nft_set_pktinfo_ipv6(&pkt, skb);
 156                 break;
 157         default:
 158                 break;
 159         }
 160
 161         return nft_do_chain(&pkt, priv);
 162 }
 163
 164 static const struct nft_chain_type nft_chain_filter_inet = {
 165         .name           = "filter",
 166         .type           = NFT_CHAIN_T_DEFAULT,
 167         .family         = NFPROTO_INET,
 168         .hook_mask      = (1 << NF_INET_LOCAL_IN) |
 169                           (1 << NF_INET_LOCAL_OUT) |
 170                           (1 << NF_INET_FORWARD) |
 171                           (1 << NF_INET_PRE_ROUTING) |
 172                           (1 << NF_INET_POST_ROUTING),
 173         .hooks          = {
 174                 [NF_INET_LOCAL_IN]      = nft_do_chain_inet,
 175                 [NF_INET_LOCAL_OUT]     = nft_do_chain_inet,
 176                 [NF_INET_FORWARD]       = nft_do_chain_inet,
 177                 [NF_INET_PRE_ROUTING]   = nft_do_chain_inet,
 178                 [NF_INET_POST_ROUTING]  = nft_do_chain_inet,
 179         },
 180 };
 181
 182 static void nft_chain_filter_inet_init(void)
 183 {
 184         nft_register_chain_type(&nft_chain_filter_inet);
 185 }
 186
 187 static void nft_chain_filter_inet_fini(void)
 188 {
 189         nft_unregister_chain_type(&nft_chain_filter_inet);
 190 }
 191 #else
 192 static inline void nft_chain_filter_inet_init(void) {}
 193 static inline void nft_chain_filter_inet_fini(void) {}
 194 #endif /* CONFIG_NF_TABLES_IPV6 */
 195
 196 #if IS_ENABLED(CONFIG_NF_TABLES_BRIDGE)
 197 static unsigned int
 198 nft_do_chain_bridge(void *priv,
 199                     struct sk_buff *skb,
 200                     const struct nf_hook_state *state)
 201 {
 202         struct nft_pktinfo pkt;
 203
 204         nft_set_pktinfo(&pkt, skb, state);
 205
 206         switch (eth_hdr(skb)->h_proto) {
 207         case htons(ETH_P_IP):
 208                 nft_set_pktinfo_ipv4_validate(&pkt, skb);
 209                 break;
 210         case htons(ETH_P_IPV6):
 211                 nft_set_pktinfo_ipv6_validate(&pkt, skb);
 212                 break;
 213         default:
 214                 nft_set_pktinfo_unspec(&pkt, skb);
 215                 break;
 216         }
 217
 218         return nft_do_chain(&pkt, priv);
 219 }
 220
 221 static const struct nft_chain_type nft_chain_filter_bridge = {
 222         .name           = "filter",
 223         .type           = NFT_CHAIN_T_DEFAULT,
 224         .family         = NFPROTO_BRIDGE,
 225         .hook_mask      = (1 << NF_BR_PRE_ROUTING) |
 226                           (1 << NF_BR_LOCAL_IN) |
 227                           (1 << NF_BR_FORWARD) |
 228                           (1 << NF_BR_LOCAL_OUT) |
 229                           (1 << NF_BR_POST_ROUTING),
 230         .hooks          = {
 231                 [NF_BR_PRE_ROUTING]     = nft_do_chain_bridge,
 232                 [NF_BR_LOCAL_IN]        = nft_do_chain_bridge,
 233                 [NF_BR_FORWARD]         = nft_do_chain_bridge,
 234                 [NF_BR_LOCAL_OUT]       = nft_do_chain_bridge,
 235                 [NF_BR_POST_ROUTING]    = nft_do_chain_bridge,
 236         },
 237 };
 238
 239 static void nft_chain_filter_bridge_init(void)
 240 {
 241         nft_register_chain_type(&nft_chain_filter_bridge);
 242 }
 243
 244 static void nft_chain_filter_bridge_fini(void)
 245 {
 246         nft_unregister_chain_type(&nft_chain_filter_bridge);
 247 }
 248 #else
 249 static inline void nft_chain_filter_bridge_init(void) {}
 250 static inline void nft_chain_filter_bridge_fini(void) {}
 251 #endif /* CONFIG_NF_TABLES_BRIDGE */
 252
 253 #ifdef CONFIG_NF_TABLES_NETDEV
 254 static unsigned int nft_do_chain_netdev(void *priv, struct sk_buff *skb,
 255                                         const struct nf_hook_state *state)
 256 {
 257         struct nft_pktinfo pkt;
 258
 259         nft_set_pktinfo(&pkt, skb, state);
 260
 261         switch (skb->protocol) {
 262         case htons(ETH_P_IP):
 263                 nft_set_pktinfo_ipv4_validate(&pkt, skb);
 264                 break;
 265         case htons(ETH_P_IPV6):
 266                 nft_set_pktinfo_ipv6_validate(&pkt, skb);
 267                 break;
 268         default:
 269                 nft_set_pktinfo_unspec(&pkt, skb);
 270                 break;
 271         }
 272
 273         return nft_do_chain(&pkt, priv);
 274 }
 275
 276 static const struct nft_chain_type nft_chain_filter_netdev = {
 277         .name           = "filter",
 278         .type           = NFT_CHAIN_T_DEFAULT,
 279         .family         = NFPROTO_NETDEV,
 280         .hook_mask      = (1 << NF_NETDEV_INGRESS),
 281         .hooks          = {
 282                 [NF_NETDEV_INGRESS]     = nft_do_chain_netdev,
 283         },
 284 };
 285
 286 static void nft_netdev_event(unsigned long event, struct net_device *dev,
 287                              struct nft_ctx *ctx)
 288 {
 289         struct nft_base_chain *basechain = nft_base_chain(ctx->chain);
 290         struct nft_hook *hook, *found = NULL;
 291         int n = 0;
 292
 293         if (event != NETDEV_UNREGISTER)
 294                 return;
 295
 296         list_for_each_entry(hook, &basechain->hook_list, list) {
 297                 if (hook->ops.dev == dev)
 298                         found = hook;
 299
 300                 n++;
 301         }
 302         if (!found)
 303                 return;
 304
 305         if (n > 1) {
 306                 nf_unregister_net_hook(ctx->net, &found->ops);
 307                 list_del_rcu(&found->list);
 308                 kfree_rcu(found, rcu);
 309                 return;
 310         }
 311
 312         /* UNREGISTER events are also happening on netns exit.
 313          *
 314          * Although nf_tables core releases all tables/chains, only this event
 315          * handler provides guarantee that hook->ops.dev is still accessible,
 316          * so we cannot skip exiting net namespaces.
 317          */
 318         __nft_release_basechain(ctx);
 319 }
 320
 321 static int nf_tables_netdev_event(struct notifier_block *this,
 322                                   unsigned long event, void *ptr)
 323 {
 324         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 325         struct nft_table *table;
 326         struct nft_chain *chain, *nr;
 327         struct nft_ctx ctx = {
 328                 .net    = dev_net(dev),
 329         };
 330
 331         if (event != NETDEV_UNREGISTER &&
 332             event != NETDEV_CHANGENAME)
 333                 return NOTIFY_DONE;
 334
 335         mutex_lock(&ctx.net->nft.commit_mutex);
 336         list_for_each_entry(table, &ctx.net->nft.tables, list) {
 337                 if (table->family != NFPROTO_NETDEV)
 338                         continue;
 339
 340                 ctx.family = table->family;
 341                 ctx.table = table;
 342                 list_for_each_entry_safe(chain, nr, &table->chains, list) {
 343                         if (!nft_is_base_chain(chain))
 344                                 continue;
 345
 346                         ctx.chain = chain;
 347                         nft_netdev_event(event, dev, &ctx);
 348                 }
 349         }
 350         mutex_unlock(&ctx.net->nft.commit_mutex);
 351
 352         return NOTIFY_DONE;
 353 }
 354
 355 static struct notifier_block nf_tables_netdev_notifier = {
 356         .notifier_call  = nf_tables_netdev_event,
 357 };
 358
 359 static int nft_chain_filter_netdev_init(void)
 360 {
 361         int err;
 362
 363         nft_register_chain_type(&nft_chain_filter_netdev);
 364
 365         err = register_netdevice_notifier(&nf_tables_netdev_notifier);
 366         if (err)
 367                 goto err_register_netdevice_notifier;
 368
 369         return 0;
 370
 371 err_register_netdevice_notifier:
 372         nft_unregister_chain_type(&nft_chain_filter_netdev);
 373
 374         return err;
 375 }
 376
 377 static void nft_chain_filter_netdev_fini(void)
 378 {
 379         nft_unregister_chain_type(&nft_chain_filter_netdev);
 380         unregister_netdevice_notifier(&nf_tables_netdev_notifier);
 381 }
 382 #else
 383 static inline int nft_chain_filter_netdev_init(void) { return 0; }
 384 static inline void nft_chain_filter_netdev_fini(void) {}
 385 #endif /* CONFIG_NF_TABLES_NETDEV */
 386
 387 int __init nft_chain_filter_init(void)
 388 {
 389         int err;
 390
 391         err = nft_chain_filter_netdev_init();
 392         if (err < 0)
 393                 return err;
 394
 395         nft_chain_filter_ipv4_init();
 396         nft_chain_filter_ipv6_init();
 397         nft_chain_filter_arp_init();
 398         nft_chain_filter_inet_init();
 399         nft_chain_filter_bridge_init();
 400
 401         return 0;
 402 }
 403
 404 void nft_chain_filter_fini(void)
 405 {
 406         nft_chain_filter_bridge_fini();
 407         nft_chain_filter_inet_fini();
 408         nft_chain_filter_arp_fini();
 409         nft_chain_filter_ipv6_fini();
 410         nft_chain_filter_ipv4_fini();
 411         nft_chain_filter_netdev_fini();
 412 }