net/netfilter/nft_meta.c

   1 /*
   2  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/netlink.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/netfilter/nf_tables.h>
  17 #include <linux/in.h>
  18 #include <linux/ip.h>
  19 #include <linux/ipv6.h>
  20 #include <linux/smp.h>
  21 #include <linux/static_key.h>
  22 #include <net/dst.h>
  23 #include <net/sock.h>
  24 #include <net/tcp_states.h> /* for TCP_TIME_WAIT */
  25 #include <net/netfilter/nf_tables.h>
  26 #include <net/netfilter/nf_tables_core.h>
  27 #include <net/netfilter/nft_meta.h>
  28
  29 #include <uapi/linux/netfilter_bridge.h> /* NF_BR_PRE_ROUTING */
  30
  31 static DEFINE_PER_CPU(struct rnd_state, nft_prandom_state);
  32
  33 void nft_meta_get_eval(const struct nft_expr *expr,
  34                        struct nft_regs *regs,
  35                        const struct nft_pktinfo *pkt)
  36 {
  37         const struct nft_meta *priv = nft_expr_priv(expr);
  38         const struct sk_buff *skb = pkt->skb;
  39         const struct net_device *in = nft_in(pkt), *out = nft_out(pkt);
  40         struct sock *sk;
  41         u32 *dest = &regs->data[priv->dreg];
  42
  43         switch (priv->key) {
  44         case NFT_META_LEN:
  45                 *dest = skb->len;
  46                 break;
  47         case NFT_META_PROTOCOL:
  48                 *dest = 0;
  49                 *(__be16 *)dest = skb->protocol;
  50                 break;
  51         case NFT_META_NFPROTO:
  52                 *dest = nft_pf(pkt);
  53                 break;
  54         case NFT_META_L4PROTO:
  55                 if (!pkt->tprot_set)
  56                         goto err;
  57                 *dest = pkt->tprot;
  58                 break;
  59         case NFT_META_PRIORITY:
  60                 *dest = skb->priority;
  61                 break;
  62         case NFT_META_MARK:
  63                 *dest = skb->mark;
  64                 break;
  65         case NFT_META_IIF:
  66                 if (in == NULL)
  67                         goto err;
  68                 *dest = in->ifindex;
  69                 break;
  70         case NFT_META_OIF:
  71                 if (out == NULL)
  72                         goto err;
  73                 *dest = out->ifindex;
  74                 break;
  75         case NFT_META_IIFNAME:
  76                 if (in == NULL)
  77                         goto err;
  78                 strncpy((char *)dest, in->name, IFNAMSIZ);
  79                 break;
  80         case NFT_META_OIFNAME:
  81                 if (out == NULL)
  82                         goto err;
  83                 strncpy((char *)dest, out->name, IFNAMSIZ);
  84                 break;
  85         case NFT_META_IIFTYPE:
  86                 if (in == NULL)
  87                         goto err;
  88                 *dest = 0;
  89                 *(u16 *)dest = in->type;
  90                 break;
  91         case NFT_META_OIFTYPE:
  92                 if (out == NULL)
  93                         goto err;
  94                 *dest = 0;
  95                 *(u16 *)dest = out->type;
  96                 break;
  97         case NFT_META_SKUID:
  98                 sk = skb_to_full_sk(skb);
  99                 if (!sk || !sk_fullsock(sk))
 100                         goto err;
 101
 102                 read_lock_bh(&sk->sk_callback_lock);
 103                 if (sk->sk_socket == NULL ||
 104                     sk->sk_socket->file == NULL) {
 105                         read_unlock_bh(&sk->sk_callback_lock);
 106                         goto err;
 107                 }
 108
 109                 *dest = from_kuid_munged(&init_user_ns,
 110                                 sk->sk_socket->file->f_cred->fsuid);
 111                 read_unlock_bh(&sk->sk_callback_lock);
 112                 break;
 113         case NFT_META_SKGID:
 114                 sk = skb_to_full_sk(skb);
 115                 if (!sk || !sk_fullsock(sk))
 116                         goto err;
 117
 118                 read_lock_bh(&sk->sk_callback_lock);
 119                 if (sk->sk_socket == NULL ||
 120                     sk->sk_socket->file == NULL) {
 121                         read_unlock_bh(&sk->sk_callback_lock);
 122                         goto err;
 123                 }
 124                 *dest = from_kgid_munged(&init_user_ns,
 125                                  sk->sk_socket->file->f_cred->fsgid);
 126                 read_unlock_bh(&sk->sk_callback_lock);
 127                 break;
 128 #ifdef CONFIG_IP_ROUTE_CLASSID
 129         case NFT_META_RTCLASSID: {
 130                 const struct dst_entry *dst = skb_dst(skb);
 131
 132                 if (dst == NULL)
 133                         goto err;
 134                 *dest = dst->tclassid;
 135                 break;
 136         }
 137 #endif
 138 #ifdef CONFIG_NETWORK_SECMARK
 139         case NFT_META_SECMARK:
 140                 *dest = skb->secmark;
 141                 break;
 142 #endif
 143         case NFT_META_PKTTYPE:
 144                 if (skb->pkt_type != PACKET_LOOPBACK) {
 145                         *dest = skb->pkt_type;
 146                         break;
 147                 }
 148
 149                 switch (nft_pf(pkt)) {
 150                 case NFPROTO_IPV4:
 151                         if (ipv4_is_multicast(ip_hdr(skb)->daddr))
 152                                 *dest = PACKET_MULTICAST;
 153                         else
 154                                 *dest = PACKET_BROADCAST;
 155                         break;
 156                 case NFPROTO_IPV6:
 157                         *dest = PACKET_MULTICAST;
 158                         break;
 159                 case NFPROTO_NETDEV:
 160                         switch (skb->protocol) {
 161                         case htons(ETH_P_IP): {
 162                                 int noff = skb_network_offset(skb);
 163                                 struct iphdr *iph, _iph;
 164
 165                                 iph = skb_header_pointer(skb, noff,
 166                                                          sizeof(_iph), &_iph);
 167                                 if (!iph)
 168                                         goto err;
 169
 170                                 if (ipv4_is_multicast(iph->daddr))
 171                                         *dest = PACKET_MULTICAST;
 172                                 else
 173                                         *dest = PACKET_BROADCAST;
 174
 175                                 break;
 176                         }
 177                         case htons(ETH_P_IPV6):
 178                                 *dest = PACKET_MULTICAST;
 179                                 break;
 180                         default:
 181                                 WARN_ON_ONCE(1);
 182                                 goto err;
 183                         }
 184                         break;
 185                 default:
 186                         WARN_ON_ONCE(1);
 187                         goto err;
 188                 }
 189                 break;
 190         case NFT_META_CPU:
 191                 *dest = raw_smp_processor_id();
 192                 break;
 193         case NFT_META_IIFGROUP:
 194                 if (in == NULL)
 195                         goto err;
 196                 *dest = in->group;
 197                 break;
 198         case NFT_META_OIFGROUP:
 199                 if (out == NULL)
 200                         goto err;
 201                 *dest = out->group;
 202                 break;
 203 #ifdef CONFIG_CGROUP_NET_CLASSID
 204         case NFT_META_CGROUP:
 205                 sk = skb_to_full_sk(skb);
 206                 if (!sk || !sk_fullsock(sk))
 207                         goto err;
 208                 *dest = sock_cgroup_classid(&sk->sk_cgrp_data);
 209                 break;
 210 #endif
 211         case NFT_META_PRANDOM: {
 212                 struct rnd_state *state = this_cpu_ptr(&nft_prandom_state);
 213                 *dest = prandom_u32_state(state);
 214                 break;
 215         }
 216         default:
 217                 WARN_ON(1);
 218                 goto err;
 219         }
 220         return;
 221
 222 err:
 223         regs->verdict.code = NFT_BREAK;
 224 }
 225 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 226
 227 void nft_meta_set_eval(const struct nft_expr *expr,
 228                        struct nft_regs *regs,
 229                        const struct nft_pktinfo *pkt)
 230 {
 231         const struct nft_meta *meta = nft_expr_priv(expr);
 232         struct sk_buff *skb = pkt->skb;
 233         u32 value = regs->data[meta->sreg];
 234
 235         switch (meta->key) {
 236         case NFT_META_MARK:
 237                 skb->mark = value;
 238                 break;
 239         case NFT_META_PRIORITY:
 240                 skb->priority = value;
 241                 break;
 242         case NFT_META_PKTTYPE:
 243                 if (skb->pkt_type != value &&
 244                     skb_pkt_type_ok(value) && skb_pkt_type_ok(skb->pkt_type))
 245                         skb->pkt_type = value;
 246                 break;
 247         case NFT_META_NFTRACE:
 248                 skb->nf_trace = !!value;
 249                 break;
 250         default:
 251                 WARN_ON(1);
 252         }
 253 }
 254 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 255
 256 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 257         [NFTA_META_DREG]        = { .type = NLA_U32 },
 258         [NFTA_META_KEY]         = { .type = NLA_U32 },
 259         [NFTA_META_SREG]        = { .type = NLA_U32 },
 260 };
 261 EXPORT_SYMBOL_GPL(nft_meta_policy);
 262
 263 int nft_meta_get_init(const struct nft_ctx *ctx,
 264                       const struct nft_expr *expr,
 265                       const struct nlattr * const tb[])
 266 {
 267         struct nft_meta *priv = nft_expr_priv(expr);
 268         unsigned int len;
 269
 270         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 271         switch (priv->key) {
 272         case NFT_META_PROTOCOL:
 273         case NFT_META_IIFTYPE:
 274         case NFT_META_OIFTYPE:
 275                 len = sizeof(u16);
 276                 break;
 277         case NFT_META_NFPROTO:
 278         case NFT_META_L4PROTO:
 279         case NFT_META_LEN:
 280         case NFT_META_PRIORITY:
 281         case NFT_META_MARK:
 282         case NFT_META_IIF:
 283         case NFT_META_OIF:
 284         case NFT_META_SKUID:
 285         case NFT_META_SKGID:
 286 #ifdef CONFIG_IP_ROUTE_CLASSID
 287         case NFT_META_RTCLASSID:
 288 #endif
 289 #ifdef CONFIG_NETWORK_SECMARK
 290         case NFT_META_SECMARK:
 291 #endif
 292         case NFT_META_PKTTYPE:
 293         case NFT_META_CPU:
 294         case NFT_META_IIFGROUP:
 295         case NFT_META_OIFGROUP:
 296 #ifdef CONFIG_CGROUP_NET_CLASSID
 297         case NFT_META_CGROUP:
 298 #endif
 299                 len = sizeof(u32);
 300                 break;
 301         case NFT_META_IIFNAME:
 302         case NFT_META_OIFNAME:
 303                 len = IFNAMSIZ;
 304                 break;
 305         case NFT_META_PRANDOM:
 306                 prandom_init_once(&nft_prandom_state);
 307                 len = sizeof(u32);
 308                 break;
 309         default:
 310                 return -EOPNOTSUPP;
 311         }
 312
 313         priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
 314         return nft_validate_register_store(ctx, priv->dreg, NULL,
 315                                            NFT_DATA_VALUE, len);
 316 }
 317 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 318
 319 int nft_meta_set_validate(const struct nft_ctx *ctx,
 320                           const struct nft_expr *expr,
 321                           const struct nft_data **data)
 322 {
 323         struct nft_meta *priv = nft_expr_priv(expr);
 324         unsigned int hooks;
 325
 326         if (priv->key != NFT_META_PKTTYPE)
 327                 return 0;
 328
 329         switch (ctx->afi->family) {
 330         case NFPROTO_BRIDGE:
 331                 hooks = 1 << NF_BR_PRE_ROUTING;
 332                 break;
 333         case NFPROTO_NETDEV:
 334                 hooks = 1 << NF_NETDEV_INGRESS;
 335                 break;
 336         case NFPROTO_IPV4:
 337         case NFPROTO_IPV6:
 338         case NFPROTO_INET:
 339                 hooks = 1 << NF_INET_PRE_ROUTING;
 340                 break;
 341         default:
 342                 return -EOPNOTSUPP;
 343         }
 344
 345         return nft_chain_validate_hooks(ctx->chain, hooks);
 346 }
 347 EXPORT_SYMBOL_GPL(nft_meta_set_validate);
 348
 349 int nft_meta_set_init(const struct nft_ctx *ctx,
 350                       const struct nft_expr *expr,
 351                       const struct nlattr * const tb[])
 352 {
 353         struct nft_meta *priv = nft_expr_priv(expr);
 354         unsigned int len;
 355         int err;
 356
 357         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 358         switch (priv->key) {
 359         case NFT_META_MARK:
 360         case NFT_META_PRIORITY:
 361                 len = sizeof(u32);
 362                 break;
 363         case NFT_META_NFTRACE:
 364                 len = sizeof(u8);
 365                 break;
 366         case NFT_META_PKTTYPE:
 367                 len = sizeof(u8);
 368                 break;
 369         default:
 370                 return -EOPNOTSUPP;
 371         }
 372
 373         err = nft_meta_set_validate(ctx, expr, NULL);
 374         if (err < 0)
 375                 return err;
 376
 377         priv->sreg = nft_parse_register(tb[NFTA_META_SREG]);
 378         err = nft_validate_register_load(priv->sreg, len);
 379         if (err < 0)
 380                 return err;
 381
 382         if (priv->key == NFT_META_NFTRACE)
 383                 static_branch_inc(&nft_trace_enabled);
 384
 385         return 0;
 386 }
 387 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 388
 389 int nft_meta_get_dump(struct sk_buff *skb,
 390                       const struct nft_expr *expr)
 391 {
 392         const struct nft_meta *priv = nft_expr_priv(expr);
 393
 394         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 395                 goto nla_put_failure;
 396         if (nft_dump_register(skb, NFTA_META_DREG, priv->dreg))
 397                 goto nla_put_failure;
 398         return 0;
 399
 400 nla_put_failure:
 401         return -1;
 402 }
 403 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 404
 405 int nft_meta_set_dump(struct sk_buff *skb,
 406                       const struct nft_expr *expr)
 407 {
 408         const struct nft_meta *priv = nft_expr_priv(expr);
 409
 410         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 411                 goto nla_put_failure;
 412         if (nft_dump_register(skb, NFTA_META_SREG, priv->sreg))
 413                 goto nla_put_failure;
 414
 415         return 0;
 416
 417 nla_put_failure:
 418         return -1;
 419 }
 420 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 421
 422 void nft_meta_set_destroy(const struct nft_ctx *ctx,
 423                           const struct nft_expr *expr)
 424 {
 425         const struct nft_meta *priv = nft_expr_priv(expr);
 426
 427         if (priv->key == NFT_META_NFTRACE)
 428                 static_branch_dec(&nft_trace_enabled);
 429 }
 430 EXPORT_SYMBOL_GPL(nft_meta_set_destroy);
 431
 432 static struct nft_expr_type nft_meta_type;
 433 static const struct nft_expr_ops nft_meta_get_ops = {
 434         .type           = &nft_meta_type,
 435         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 436         .eval           = nft_meta_get_eval,
 437         .init           = nft_meta_get_init,
 438         .dump           = nft_meta_get_dump,
 439 };
 440
 441 static const struct nft_expr_ops nft_meta_set_ops = {
 442         .type           = &nft_meta_type,
 443         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 444         .eval           = nft_meta_set_eval,
 445         .init           = nft_meta_set_init,
 446         .destroy        = nft_meta_set_destroy,
 447         .dump           = nft_meta_set_dump,
 448         .validate       = nft_meta_set_validate,
 449 };
 450
 451 static const struct nft_expr_ops *
 452 nft_meta_select_ops(const struct nft_ctx *ctx,
 453                     const struct nlattr * const tb[])
 454 {
 455         if (tb[NFTA_META_KEY] == NULL)
 456                 return ERR_PTR(-EINVAL);
 457
 458         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 459                 return ERR_PTR(-EINVAL);
 460
 461         if (tb[NFTA_META_DREG])
 462                 return &nft_meta_get_ops;
 463
 464         if (tb[NFTA_META_SREG])
 465                 return &nft_meta_set_ops;
 466
 467         return ERR_PTR(-EINVAL);
 468 }
 469
 470 static struct nft_expr_type nft_meta_type __read_mostly = {
 471         .name           = "meta",
 472         .select_ops     = &nft_meta_select_ops,
 473         .policy         = nft_meta_policy,
 474         .maxattr        = NFTA_META_MAX,
 475         .owner          = THIS_MODULE,
 476 };
 477
 478 static int __init nft_meta_module_init(void)
 479 {
 480         return nft_register_expr(&nft_meta_type);
 481 }
 482
 483 static void __exit nft_meta_module_exit(void)
 484 {
 485         nft_unregister_expr(&nft_meta_type);
 486 }
 487
 488 module_init(nft_meta_module_init);
 489 module_exit(nft_meta_module_exit);
 490
 491 MODULE_LICENSE("GPL");
 492 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 493 MODULE_ALIAS_NFT_EXPR("meta");