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 = pkt->in, *out = pkt->out;
  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 = pkt->pf;
  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 (pkt->pf) {
 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                         if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
 158                                 *dest = PACKET_MULTICAST;
 159                         else
 160                                 *dest = PACKET_BROADCAST;
 161                         break;
 162                 default:
 163                         WARN_ON(1);
 164                         goto err;
 165                 }
 166                 break;
 167         case NFT_META_CPU:
 168                 *dest = raw_smp_processor_id();
 169                 break;
 170         case NFT_META_IIFGROUP:
 171                 if (in == NULL)
 172                         goto err;
 173                 *dest = in->group;
 174                 break;
 175         case NFT_META_OIFGROUP:
 176                 if (out == NULL)
 177                         goto err;
 178                 *dest = out->group;
 179                 break;
 180 #ifdef CONFIG_CGROUP_NET_CLASSID
 181         case NFT_META_CGROUP:
 182                 sk = skb_to_full_sk(skb);
 183                 if (!sk || !sk_fullsock(sk))
 184                         goto err;
 185                 *dest = sock_cgroup_classid(&sk->sk_cgrp_data);
 186                 break;
 187 #endif
 188         case NFT_META_PRANDOM: {
 189                 struct rnd_state *state = this_cpu_ptr(&nft_prandom_state);
 190                 *dest = prandom_u32_state(state);
 191                 break;
 192         }
 193         default:
 194                 WARN_ON(1);
 195                 goto err;
 196         }
 197         return;
 198
 199 err:
 200         regs->verdict.code = NFT_BREAK;
 201 }
 202 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 203
 204 void nft_meta_set_eval(const struct nft_expr *expr,
 205                        struct nft_regs *regs,
 206                        const struct nft_pktinfo *pkt)
 207 {
 208         const struct nft_meta *meta = nft_expr_priv(expr);
 209         struct sk_buff *skb = pkt->skb;
 210         u32 value = regs->data[meta->sreg];
 211
 212         switch (meta->key) {
 213         case NFT_META_MARK:
 214                 skb->mark = value;
 215                 break;
 216         case NFT_META_PRIORITY:
 217                 skb->priority = value;
 218                 break;
 219         case NFT_META_PKTTYPE:
 220                 if (skb->pkt_type != value &&
 221                     skb_pkt_type_ok(value) && skb_pkt_type_ok(skb->pkt_type))
 222                         skb->pkt_type = value;
 223                 break;
 224         case NFT_META_NFTRACE:
 225                 skb->nf_trace = !!value;
 226                 break;
 227         default:
 228                 WARN_ON(1);
 229         }
 230 }
 231 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 232
 233 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 234         [NFTA_META_DREG]        = { .type = NLA_U32 },
 235         [NFTA_META_KEY]         = { .type = NLA_U32 },
 236         [NFTA_META_SREG]        = { .type = NLA_U32 },
 237 };
 238 EXPORT_SYMBOL_GPL(nft_meta_policy);
 239
 240 int nft_meta_get_init(const struct nft_ctx *ctx,
 241                       const struct nft_expr *expr,
 242                       const struct nlattr * const tb[])
 243 {
 244         struct nft_meta *priv = nft_expr_priv(expr);
 245         unsigned int len;
 246
 247         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 248         switch (priv->key) {
 249         case NFT_META_PROTOCOL:
 250         case NFT_META_IIFTYPE:
 251         case NFT_META_OIFTYPE:
 252                 len = sizeof(u16);
 253                 break;
 254         case NFT_META_NFPROTO:
 255         case NFT_META_L4PROTO:
 256         case NFT_META_LEN:
 257         case NFT_META_PRIORITY:
 258         case NFT_META_MARK:
 259         case NFT_META_IIF:
 260         case NFT_META_OIF:
 261         case NFT_META_SKUID:
 262         case NFT_META_SKGID:
 263 #ifdef CONFIG_IP_ROUTE_CLASSID
 264         case NFT_META_RTCLASSID:
 265 #endif
 266 #ifdef CONFIG_NETWORK_SECMARK
 267         case NFT_META_SECMARK:
 268 #endif
 269         case NFT_META_PKTTYPE:
 270         case NFT_META_CPU:
 271         case NFT_META_IIFGROUP:
 272         case NFT_META_OIFGROUP:
 273 #ifdef CONFIG_CGROUP_NET_CLASSID
 274         case NFT_META_CGROUP:
 275 #endif
 276                 len = sizeof(u32);
 277                 break;
 278         case NFT_META_IIFNAME:
 279         case NFT_META_OIFNAME:
 280                 len = IFNAMSIZ;
 281                 break;
 282         case NFT_META_PRANDOM:
 283                 prandom_init_once(&nft_prandom_state);
 284                 len = sizeof(u32);
 285                 break;
 286         default:
 287                 return -EOPNOTSUPP;
 288         }
 289
 290         priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
 291         return nft_validate_register_store(ctx, priv->dreg, NULL,
 292                                            NFT_DATA_VALUE, len);
 293 }
 294 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 295
 296 int nft_meta_set_validate(const struct nft_ctx *ctx,
 297                           const struct nft_expr *expr,
 298                           const struct nft_data **data)
 299 {
 300         struct nft_meta *priv = nft_expr_priv(expr);
 301         unsigned int hooks;
 302
 303         if (priv->key != NFT_META_PKTTYPE)
 304                 return 0;
 305
 306         switch (ctx->afi->family) {
 307         case NFPROTO_BRIDGE:
 308                 hooks = 1 << NF_BR_PRE_ROUTING;
 309                 break;
 310         case NFPROTO_NETDEV:
 311                 hooks = 1 << NF_NETDEV_INGRESS;
 312                 break;
 313         default:
 314                 return -EOPNOTSUPP;
 315         }
 316
 317         return nft_chain_validate_hooks(ctx->chain, hooks);
 318 }
 319 EXPORT_SYMBOL_GPL(nft_meta_set_validate);
 320
 321 int nft_meta_set_init(const struct nft_ctx *ctx,
 322                       const struct nft_expr *expr,
 323                       const struct nlattr * const tb[])
 324 {
 325         struct nft_meta *priv = nft_expr_priv(expr);
 326         unsigned int len;
 327         int err;
 328
 329         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 330         switch (priv->key) {
 331         case NFT_META_MARK:
 332         case NFT_META_PRIORITY:
 333                 len = sizeof(u32);
 334                 break;
 335         case NFT_META_NFTRACE:
 336                 len = sizeof(u8);
 337                 break;
 338         case NFT_META_PKTTYPE:
 339                 len = sizeof(u8);
 340                 break;
 341         default:
 342                 return -EOPNOTSUPP;
 343         }
 344
 345         err = nft_meta_set_validate(ctx, expr, NULL);
 346         if (err < 0)
 347                 return err;
 348
 349         priv->sreg = nft_parse_register(tb[NFTA_META_SREG]);
 350         err = nft_validate_register_load(priv->sreg, len);
 351         if (err < 0)
 352                 return err;
 353
 354         if (priv->key == NFT_META_NFTRACE)
 355                 static_branch_inc(&nft_trace_enabled);
 356
 357         return 0;
 358 }
 359 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 360
 361 int nft_meta_get_dump(struct sk_buff *skb,
 362                       const struct nft_expr *expr)
 363 {
 364         const struct nft_meta *priv = nft_expr_priv(expr);
 365
 366         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 367                 goto nla_put_failure;
 368         if (nft_dump_register(skb, NFTA_META_DREG, priv->dreg))
 369                 goto nla_put_failure;
 370         return 0;
 371
 372 nla_put_failure:
 373         return -1;
 374 }
 375 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 376
 377 int nft_meta_set_dump(struct sk_buff *skb,
 378                       const struct nft_expr *expr)
 379 {
 380         const struct nft_meta *priv = nft_expr_priv(expr);
 381
 382         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 383                 goto nla_put_failure;
 384         if (nft_dump_register(skb, NFTA_META_SREG, priv->sreg))
 385                 goto nla_put_failure;
 386
 387         return 0;
 388
 389 nla_put_failure:
 390         return -1;
 391 }
 392 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 393
 394 void nft_meta_set_destroy(const struct nft_ctx *ctx,
 395                           const struct nft_expr *expr)
 396 {
 397         const struct nft_meta *priv = nft_expr_priv(expr);
 398
 399         if (priv->key == NFT_META_NFTRACE)
 400                 static_branch_dec(&nft_trace_enabled);
 401 }
 402 EXPORT_SYMBOL_GPL(nft_meta_set_destroy);
 403
 404 static struct nft_expr_type nft_meta_type;
 405 static const struct nft_expr_ops nft_meta_get_ops = {
 406         .type           = &nft_meta_type,
 407         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 408         .eval           = nft_meta_get_eval,
 409         .init           = nft_meta_get_init,
 410         .dump           = nft_meta_get_dump,
 411 };
 412
 413 static const struct nft_expr_ops nft_meta_set_ops = {
 414         .type           = &nft_meta_type,
 415         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 416         .eval           = nft_meta_set_eval,
 417         .init           = nft_meta_set_init,
 418         .destroy        = nft_meta_set_destroy,
 419         .dump           = nft_meta_set_dump,
 420         .validate       = nft_meta_set_validate,
 421 };
 422
 423 static const struct nft_expr_ops *
 424 nft_meta_select_ops(const struct nft_ctx *ctx,
 425                     const struct nlattr * const tb[])
 426 {
 427         if (tb[NFTA_META_KEY] == NULL)
 428                 return ERR_PTR(-EINVAL);
 429
 430         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 431                 return ERR_PTR(-EINVAL);
 432
 433         if (tb[NFTA_META_DREG])
 434                 return &nft_meta_get_ops;
 435
 436         if (tb[NFTA_META_SREG])
 437                 return &nft_meta_set_ops;
 438
 439         return ERR_PTR(-EINVAL);
 440 }
 441
 442 static struct nft_expr_type nft_meta_type __read_mostly = {
 443         .name           = "meta",
 444         .select_ops     = &nft_meta_select_ops,
 445         .policy         = nft_meta_policy,
 446         .maxattr        = NFTA_META_MAX,
 447         .owner          = THIS_MODULE,
 448 };
 449
 450 static int __init nft_meta_module_init(void)
 451 {
 452         return nft_register_expr(&nft_meta_type);
 453 }
 454
 455 static void __exit nft_meta_module_exit(void)
 456 {
 457         nft_unregister_expr(&nft_meta_type);
 458 }
 459
 460 module_init(nft_meta_module_init);
 461 module_exit(nft_meta_module_exit);
 462
 463 MODULE_LICENSE("GPL");
 464 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 465 MODULE_ALIAS_NFT_EXPR("meta");