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);
  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);
  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);
 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);
 153                 break;
 154         case NFPROTO_IPV6:
 155                 nft_set_pktinfo_ipv6(&pkt);
 156                 break;
 157         default:
 158                 break;
 159         }
 160
 161         return nft_do_chain(&pkt, priv);
 162 }
 163
 164 static unsigned int nft_do_chain_inet_ingress(void *priv, struct sk_buff *skb,
 165                                               const struct nf_hook_state *state)
 166 {
 167         struct nf_hook_state ingress_state = *state;
 168         struct nft_pktinfo pkt;
 169
 170         switch (skb->protocol) {
 171         case htons(ETH_P_IP):
 172                 /* Original hook is NFPROTO_NETDEV and NF_NETDEV_INGRESS. */
 173                 ingress_state.pf = NFPROTO_IPV4;
 174                 ingress_state.hook = NF_INET_INGRESS;
 175                 nft_set_pktinfo(&pkt, skb, &ingress_state);
 176
 177                 if (nft_set_pktinfo_ipv4_ingress(&pkt) < 0)
 178                         return NF_DROP;
 179                 break;
 180         case htons(ETH_P_IPV6):
 181                 ingress_state.pf = NFPROTO_IPV6;
 182                 ingress_state.hook = NF_INET_INGRESS;
 183                 nft_set_pktinfo(&pkt, skb, &ingress_state);
 184
 185                 if (nft_set_pktinfo_ipv6_ingress(&pkt) < 0)
 186                         return NF_DROP;
 187                 break;
 188         default:
 189                 return NF_ACCEPT;
 190         }
 191
 192         return nft_do_chain(&pkt, priv);
 193 }
 194
 195 static const struct nft_chain_type nft_chain_filter_inet = {
 196         .name           = "filter",
 197         .type           = NFT_CHAIN_T_DEFAULT,
 198         .family         = NFPROTO_INET,
 199         .hook_mask      = (1 << NF_INET_INGRESS) |
 200                           (1 << NF_INET_LOCAL_IN) |
 201                           (1 << NF_INET_LOCAL_OUT) |
 202                           (1 << NF_INET_FORWARD) |
 203                           (1 << NF_INET_PRE_ROUTING) |
 204                           (1 << NF_INET_POST_ROUTING),
 205         .hooks          = {
 206                 [NF_INET_INGRESS]       = nft_do_chain_inet_ingress,
 207                 [NF_INET_LOCAL_IN]      = nft_do_chain_inet,
 208                 [NF_INET_LOCAL_OUT]     = nft_do_chain_inet,
 209                 [NF_INET_FORWARD]       = nft_do_chain_inet,
 210                 [NF_INET_PRE_ROUTING]   = nft_do_chain_inet,
 211                 [NF_INET_POST_ROUTING]  = nft_do_chain_inet,
 212         },
 213 };
 214
 215 static void nft_chain_filter_inet_init(void)
 216 {
 217         nft_register_chain_type(&nft_chain_filter_inet);
 218 }
 219
 220 static void nft_chain_filter_inet_fini(void)
 221 {
 222         nft_unregister_chain_type(&nft_chain_filter_inet);
 223 }
 224 #else
 225 static inline void nft_chain_filter_inet_init(void) {}
 226 static inline void nft_chain_filter_inet_fini(void) {}
 227 #endif /* CONFIG_NF_TABLES_IPV6 */
 228
 229 #if IS_ENABLED(CONFIG_NF_TABLES_BRIDGE)
 230 static unsigned int
 231 nft_do_chain_bridge(void *priv,
 232                     struct sk_buff *skb,
 233                     const struct nf_hook_state *state)
 234 {
 235         struct nft_pktinfo pkt;
 236
 237         nft_set_pktinfo(&pkt, skb, state);
 238
 239         switch (eth_hdr(skb)->h_proto) {
 240         case htons(ETH_P_IP):
 241                 nft_set_pktinfo_ipv4_validate(&pkt);
 242                 break;
 243         case htons(ETH_P_IPV6):
 244                 nft_set_pktinfo_ipv6_validate(&pkt);
 245                 break;
 246         default:
 247                 nft_set_pktinfo_unspec(&pkt);
 248                 break;
 249         }
 250
 251         return nft_do_chain(&pkt, priv);
 252 }
 253
 254 static const struct nft_chain_type nft_chain_filter_bridge = {
 255         .name           = "filter",
 256         .type           = NFT_CHAIN_T_DEFAULT,
 257         .family         = NFPROTO_BRIDGE,
 258         .hook_mask      = (1 << NF_BR_PRE_ROUTING) |
 259                           (1 << NF_BR_LOCAL_IN) |
 260                           (1 << NF_BR_FORWARD) |
 261                           (1 << NF_BR_LOCAL_OUT) |
 262                           (1 << NF_BR_POST_ROUTING),
 263         .hooks          = {
 264                 [NF_BR_PRE_ROUTING]     = nft_do_chain_bridge,
 265                 [NF_BR_LOCAL_IN]        = nft_do_chain_bridge,
 266                 [NF_BR_FORWARD]         = nft_do_chain_bridge,
 267                 [NF_BR_LOCAL_OUT]       = nft_do_chain_bridge,
 268                 [NF_BR_POST_ROUTING]    = nft_do_chain_bridge,
 269         },
 270 };
 271
 272 static void nft_chain_filter_bridge_init(void)
 273 {
 274         nft_register_chain_type(&nft_chain_filter_bridge);
 275 }
 276
 277 static void nft_chain_filter_bridge_fini(void)
 278 {
 279         nft_unregister_chain_type(&nft_chain_filter_bridge);
 280 }
 281 #else
 282 static inline void nft_chain_filter_bridge_init(void) {}
 283 static inline void nft_chain_filter_bridge_fini(void) {}
 284 #endif /* CONFIG_NF_TABLES_BRIDGE */
 285
 286 #ifdef CONFIG_NF_TABLES_NETDEV
 287 static unsigned int nft_do_chain_netdev(void *priv, struct sk_buff *skb,
 288                                         const struct nf_hook_state *state)
 289 {
 290         struct nft_pktinfo pkt;
 291
 292         nft_set_pktinfo(&pkt, skb, state);
 293
 294         switch (skb->protocol) {
 295         case htons(ETH_P_IP):
 296                 nft_set_pktinfo_ipv4_validate(&pkt);
 297                 break;
 298         case htons(ETH_P_IPV6):
 299                 nft_set_pktinfo_ipv6_validate(&pkt);
 300                 break;
 301         default:
 302                 nft_set_pktinfo_unspec(&pkt);
 303                 break;
 304         }
 305
 306         return nft_do_chain(&pkt, priv);
 307 }
 308
 309 static const struct nft_chain_type nft_chain_filter_netdev = {
 310         .name           = "filter",
 311         .type           = NFT_CHAIN_T_DEFAULT,
 312         .family         = NFPROTO_NETDEV,
 313         .hook_mask      = (1 << NF_NETDEV_INGRESS) |
 314                           (1 << NF_NETDEV_EGRESS),
 315         .hooks          = {
 316                 [NF_NETDEV_INGRESS]     = nft_do_chain_netdev,
 317                 [NF_NETDEV_EGRESS]      = nft_do_chain_netdev,
 318         },
 319 };
 320
 321 static void nft_netdev_event(unsigned long event, struct net_device *dev,
 322                              struct nft_ctx *ctx)
 323 {
 324         struct nft_base_chain *basechain = nft_base_chain(ctx->chain);
 325         struct nft_hook *hook, *found = NULL;
 326         int n = 0;
 327
 328         if (event != NETDEV_UNREGISTER)
 329                 return;
 330
 331         list_for_each_entry(hook, &basechain->hook_list, list) {
 332                 if (hook->ops.dev == dev)
 333                         found = hook;
 334
 335                 n++;
 336         }
 337         if (!found)
 338                 return;
 339
 340         if (n > 1) {
 341                 nf_unregister_net_hook(ctx->net, &found->ops);
 342                 list_del_rcu(&found->list);
 343                 kfree_rcu(found, rcu);
 344                 return;
 345         }
 346
 347         /* UNREGISTER events are also happening on netns exit.
 348          *
 349          * Although nf_tables core releases all tables/chains, only this event
 350          * handler provides guarantee that hook->ops.dev is still accessible,
 351          * so we cannot skip exiting net namespaces.
 352          */
 353         __nft_release_basechain(ctx);
 354 }
 355
 356 static int nf_tables_netdev_event(struct notifier_block *this,
 357                                   unsigned long event, void *ptr)
 358 {
 359         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 360         struct nft_base_chain *basechain;
 361         struct nftables_pernet *nft_net;
 362         struct nft_chain *chain, *nr;
 363         struct nft_table *table;
 364         struct nft_ctx ctx = {
 365                 .net    = dev_net(dev),
 366         };
 367
 368         if (event != NETDEV_UNREGISTER &&
 369             event != NETDEV_CHANGENAME)
 370                 return NOTIFY_DONE;
 371
 372         nft_net = nft_pernet(ctx.net);
 373         mutex_lock(&nft_net->commit_mutex);
 374         list_for_each_entry(table, &nft_net->tables, list) {
 375                 if (table->family != NFPROTO_NETDEV &&
 376                     table->family != NFPROTO_INET)
 377                         continue;
 378
 379                 ctx.family = table->family;
 380                 ctx.table = table;
 381                 list_for_each_entry_safe(chain, nr, &table->chains, list) {
 382                         if (!nft_is_base_chain(chain))
 383                                 continue;
 384
 385                         basechain = nft_base_chain(chain);
 386                         if (table->family == NFPROTO_INET &&
 387                             basechain->ops.hooknum != NF_INET_INGRESS)
 388                                 continue;
 389
 390                         ctx.chain = chain;
 391                         nft_netdev_event(event, dev, &ctx);
 392                 }
 393         }
 394         mutex_unlock(&nft_net->commit_mutex);
 395
 396         return NOTIFY_DONE;
 397 }
 398
 399 static struct notifier_block nf_tables_netdev_notifier = {
 400         .notifier_call  = nf_tables_netdev_event,
 401 };
 402
 403 static int nft_chain_filter_netdev_init(void)
 404 {
 405         int err;
 406
 407         nft_register_chain_type(&nft_chain_filter_netdev);
 408
 409         err = register_netdevice_notifier(&nf_tables_netdev_notifier);
 410         if (err)
 411                 goto err_register_netdevice_notifier;
 412
 413         return 0;
 414
 415 err_register_netdevice_notifier:
 416         nft_unregister_chain_type(&nft_chain_filter_netdev);
 417
 418         return err;
 419 }
 420
 421 static void nft_chain_filter_netdev_fini(void)
 422 {
 423         nft_unregister_chain_type(&nft_chain_filter_netdev);
 424         unregister_netdevice_notifier(&nf_tables_netdev_notifier);
 425 }
 426 #else
 427 static inline int nft_chain_filter_netdev_init(void) { return 0; }
 428 static inline void nft_chain_filter_netdev_fini(void) {}
 429 #endif /* CONFIG_NF_TABLES_NETDEV */
 430
 431 int __init nft_chain_filter_init(void)
 432 {
 433         int err;
 434
 435         err = nft_chain_filter_netdev_init();
 436         if (err < 0)
 437                 return err;
 438
 439         nft_chain_filter_ipv4_init();
 440         nft_chain_filter_ipv6_init();
 441         nft_chain_filter_arp_init();
 442         nft_chain_filter_inet_init();
 443         nft_chain_filter_bridge_init();
 444
 445         return 0;
 446 }
 447
 448 void nft_chain_filter_fini(void)
 449 {
 450         nft_chain_filter_bridge_fini();
 451         nft_chain_filter_inet_fini();
 452         nft_chain_filter_arp_fini();
 453         nft_chain_filter_ipv6_fini();
 454         nft_chain_filter_ipv4_fini();
 455         nft_chain_filter_netdev_fini();
 456 }