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                 *dest = pkt->tprot;
  56                 break;
  57         case NFT_META_PRIORITY:
  58                 *dest = skb->priority;
  59                 break;
  60         case NFT_META_MARK:
  61                 *dest = skb->mark;
  62                 break;
  63         case NFT_META_IIF:
  64                 if (in == NULL)
  65                         goto err;
  66                 *dest = in->ifindex;
  67                 break;
  68         case NFT_META_OIF:
  69                 if (out == NULL)
  70                         goto err;
  71                 *dest = out->ifindex;
  72                 break;
  73         case NFT_META_IIFNAME:
  74                 if (in == NULL)
  75                         goto err;
  76                 strncpy((char *)dest, in->name, IFNAMSIZ);
  77                 break;
  78         case NFT_META_OIFNAME:
  79                 if (out == NULL)
  80                         goto err;
  81                 strncpy((char *)dest, out->name, IFNAMSIZ);
  82                 break;
  83         case NFT_META_IIFTYPE:
  84                 if (in == NULL)
  85                         goto err;
  86                 *dest = 0;
  87                 *(u16 *)dest = in->type;
  88                 break;
  89         case NFT_META_OIFTYPE:
  90                 if (out == NULL)
  91                         goto err;
  92                 *dest = 0;
  93                 *(u16 *)dest = out->type;
  94                 break;
  95         case NFT_META_SKUID:
  96                 sk = skb_to_full_sk(skb);
  97                 if (!sk || !sk_fullsock(sk))
  98                         goto err;
  99
 100                 read_lock_bh(&sk->sk_callback_lock);
 101                 if (sk->sk_socket == NULL ||
 102                     sk->sk_socket->file == NULL) {
 103                         read_unlock_bh(&sk->sk_callback_lock);
 104                         goto err;
 105                 }
 106
 107                 *dest = from_kuid_munged(&init_user_ns,
 108                                 sk->sk_socket->file->f_cred->fsuid);
 109                 read_unlock_bh(&sk->sk_callback_lock);
 110                 break;
 111         case NFT_META_SKGID:
 112                 sk = skb_to_full_sk(skb);
 113                 if (!sk || !sk_fullsock(sk))
 114                         goto err;
 115
 116                 read_lock_bh(&sk->sk_callback_lock);
 117                 if (sk->sk_socket == NULL ||
 118                     sk->sk_socket->file == NULL) {
 119                         read_unlock_bh(&sk->sk_callback_lock);
 120                         goto err;
 121                 }
 122                 *dest = from_kgid_munged(&init_user_ns,
 123                                  sk->sk_socket->file->f_cred->fsgid);
 124                 read_unlock_bh(&sk->sk_callback_lock);
 125                 break;
 126 #ifdef CONFIG_IP_ROUTE_CLASSID
 127         case NFT_META_RTCLASSID: {
 128                 const struct dst_entry *dst = skb_dst(skb);
 129
 130                 if (dst == NULL)
 131                         goto err;
 132                 *dest = dst->tclassid;
 133                 break;
 134         }
 135 #endif
 136 #ifdef CONFIG_NETWORK_SECMARK
 137         case NFT_META_SECMARK:
 138                 *dest = skb->secmark;
 139                 break;
 140 #endif
 141         case NFT_META_PKTTYPE:
 142                 if (skb->pkt_type != PACKET_LOOPBACK) {
 143                         *dest = skb->pkt_type;
 144                         break;
 145                 }
 146
 147                 switch (pkt->pf) {
 148                 case NFPROTO_IPV4:
 149                         if (ipv4_is_multicast(ip_hdr(skb)->daddr))
 150                                 *dest = PACKET_MULTICAST;
 151                         else
 152                                 *dest = PACKET_BROADCAST;
 153                         break;
 154                 case NFPROTO_IPV6:
 155                         if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
 156                                 *dest = PACKET_MULTICAST;
 157                         else
 158                                 *dest = PACKET_BROADCAST;
 159                         break;
 160                 default:
 161                         WARN_ON(1);
 162                         goto err;
 163                 }
 164                 break;
 165         case NFT_META_CPU:
 166                 *dest = raw_smp_processor_id();
 167                 break;
 168         case NFT_META_IIFGROUP:
 169                 if (in == NULL)
 170                         goto err;
 171                 *dest = in->group;
 172                 break;
 173         case NFT_META_OIFGROUP:
 174                 if (out == NULL)
 175                         goto err;
 176                 *dest = out->group;
 177                 break;
 178 #ifdef CONFIG_CGROUP_NET_CLASSID
 179         case NFT_META_CGROUP:
 180                 sk = skb_to_full_sk(skb);
 181                 if (!sk || !sk_fullsock(sk))
 182                         goto err;
 183                 *dest = sock_cgroup_classid(&sk->sk_cgrp_data);
 184                 break;
 185 #endif
 186         case NFT_META_PRANDOM: {
 187                 struct rnd_state *state = this_cpu_ptr(&nft_prandom_state);
 188                 *dest = prandom_u32_state(state);
 189                 break;
 190         }
 191         default:
 192                 WARN_ON(1);
 193                 goto err;
 194         }
 195         return;
 196
 197 err:
 198         regs->verdict.code = NFT_BREAK;
 199 }
 200 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 201
 202 void nft_meta_set_eval(const struct nft_expr *expr,
 203                        struct nft_regs *regs,
 204                        const struct nft_pktinfo *pkt)
 205 {
 206         const struct nft_meta *meta = nft_expr_priv(expr);
 207         struct sk_buff *skb = pkt->skb;
 208         u32 value = regs->data[meta->sreg];
 209
 210         switch (meta->key) {
 211         case NFT_META_MARK:
 212                 skb->mark = value;
 213                 break;
 214         case NFT_META_PRIORITY:
 215                 skb->priority = value;
 216                 break;
 217         case NFT_META_PKTTYPE:
 218                 if (skb->pkt_type != value &&
 219                     skb_pkt_type_ok(value) && skb_pkt_type_ok(skb->pkt_type))
 220                         skb->pkt_type = value;
 221                 break;
 222         case NFT_META_NFTRACE:
 223                 skb->nf_trace = !!value;
 224                 break;
 225         default:
 226                 WARN_ON(1);
 227         }
 228 }
 229 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 230
 231 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 232         [NFTA_META_DREG]        = { .type = NLA_U32 },
 233         [NFTA_META_KEY]         = { .type = NLA_U32 },
 234         [NFTA_META_SREG]        = { .type = NLA_U32 },
 235 };
 236 EXPORT_SYMBOL_GPL(nft_meta_policy);
 237
 238 int nft_meta_get_init(const struct nft_ctx *ctx,
 239                       const struct nft_expr *expr,
 240                       const struct nlattr * const tb[])
 241 {
 242         struct nft_meta *priv = nft_expr_priv(expr);
 243         unsigned int len;
 244
 245         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 246         switch (priv->key) {
 247         case NFT_META_PROTOCOL:
 248         case NFT_META_IIFTYPE:
 249         case NFT_META_OIFTYPE:
 250                 len = sizeof(u16);
 251                 break;
 252         case NFT_META_NFPROTO:
 253         case NFT_META_L4PROTO:
 254         case NFT_META_LEN:
 255         case NFT_META_PRIORITY:
 256         case NFT_META_MARK:
 257         case NFT_META_IIF:
 258         case NFT_META_OIF:
 259         case NFT_META_SKUID:
 260         case NFT_META_SKGID:
 261 #ifdef CONFIG_IP_ROUTE_CLASSID
 262         case NFT_META_RTCLASSID:
 263 #endif
 264 #ifdef CONFIG_NETWORK_SECMARK
 265         case NFT_META_SECMARK:
 266 #endif
 267         case NFT_META_PKTTYPE:
 268         case NFT_META_CPU:
 269         case NFT_META_IIFGROUP:
 270         case NFT_META_OIFGROUP:
 271 #ifdef CONFIG_CGROUP_NET_CLASSID
 272         case NFT_META_CGROUP:
 273 #endif
 274                 len = sizeof(u32);
 275                 break;
 276         case NFT_META_IIFNAME:
 277         case NFT_META_OIFNAME:
 278                 len = IFNAMSIZ;
 279                 break;
 280         case NFT_META_PRANDOM:
 281                 prandom_init_once(&nft_prandom_state);
 282                 len = sizeof(u32);
 283                 break;
 284         default:
 285                 return -EOPNOTSUPP;
 286         }
 287
 288         priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
 289         return nft_validate_register_store(ctx, priv->dreg, NULL,
 290                                            NFT_DATA_VALUE, len);
 291 }
 292 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 293
 294 static int nft_meta_set_init_pkttype(const struct nft_ctx *ctx)
 295 {
 296         unsigned int hooks;
 297
 298         switch (ctx->afi->family) {
 299         case NFPROTO_BRIDGE:
 300                 hooks = 1 << NF_BR_PRE_ROUTING;
 301                 break;
 302         case NFPROTO_NETDEV:
 303                 hooks = 1 << NF_NETDEV_INGRESS;
 304                 break;
 305         default:
 306                 return -EOPNOTSUPP;
 307         }
 308
 309         return nft_chain_validate_hooks(ctx->chain, hooks);
 310 }
 311
 312 int nft_meta_set_init(const struct nft_ctx *ctx,
 313                       const struct nft_expr *expr,
 314                       const struct nlattr * const tb[])
 315 {
 316         struct nft_meta *priv = nft_expr_priv(expr);
 317         unsigned int len;
 318         int err;
 319
 320         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 321         switch (priv->key) {
 322         case NFT_META_MARK:
 323         case NFT_META_PRIORITY:
 324                 len = sizeof(u32);
 325                 break;
 326         case NFT_META_NFTRACE:
 327                 len = sizeof(u8);
 328                 break;
 329         case NFT_META_PKTTYPE:
 330                 err = nft_meta_set_init_pkttype(ctx);
 331                 if (err)
 332                         return err;
 333                 len = sizeof(u8);
 334                 break;
 335         default:
 336                 return -EOPNOTSUPP;
 337         }
 338
 339         priv->sreg = nft_parse_register(tb[NFTA_META_SREG]);
 340         err = nft_validate_register_load(priv->sreg, len);
 341         if (err < 0)
 342                 return err;
 343
 344         if (priv->key == NFT_META_NFTRACE)
 345                 static_branch_inc(&nft_trace_enabled);
 346
 347         return 0;
 348 }
 349 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 350
 351 int nft_meta_get_dump(struct sk_buff *skb,
 352                       const struct nft_expr *expr)
 353 {
 354         const struct nft_meta *priv = nft_expr_priv(expr);
 355
 356         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 357                 goto nla_put_failure;
 358         if (nft_dump_register(skb, NFTA_META_DREG, priv->dreg))
 359                 goto nla_put_failure;
 360         return 0;
 361
 362 nla_put_failure:
 363         return -1;
 364 }
 365 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 366
 367 int nft_meta_set_dump(struct sk_buff *skb,
 368                       const struct nft_expr *expr)
 369 {
 370         const struct nft_meta *priv = nft_expr_priv(expr);
 371
 372         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 373                 goto nla_put_failure;
 374         if (nft_dump_register(skb, NFTA_META_SREG, priv->sreg))
 375                 goto nla_put_failure;
 376
 377         return 0;
 378
 379 nla_put_failure:
 380         return -1;
 381 }
 382 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 383
 384 void nft_meta_set_destroy(const struct nft_ctx *ctx,
 385                           const struct nft_expr *expr)
 386 {
 387         const struct nft_meta *priv = nft_expr_priv(expr);
 388
 389         if (priv->key == NFT_META_NFTRACE)
 390                 static_branch_dec(&nft_trace_enabled);
 391 }
 392 EXPORT_SYMBOL_GPL(nft_meta_set_destroy);
 393
 394 static struct nft_expr_type nft_meta_type;
 395 static const struct nft_expr_ops nft_meta_get_ops = {
 396         .type           = &nft_meta_type,
 397         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 398         .eval           = nft_meta_get_eval,
 399         .init           = nft_meta_get_init,
 400         .dump           = nft_meta_get_dump,
 401 };
 402
 403 static const struct nft_expr_ops nft_meta_set_ops = {
 404         .type           = &nft_meta_type,
 405         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 406         .eval           = nft_meta_set_eval,
 407         .init           = nft_meta_set_init,
 408         .destroy        = nft_meta_set_destroy,
 409         .dump           = nft_meta_set_dump,
 410 };
 411
 412 static const struct nft_expr_ops *
 413 nft_meta_select_ops(const struct nft_ctx *ctx,
 414                     const struct nlattr * const tb[])
 415 {
 416         if (tb[NFTA_META_KEY] == NULL)
 417                 return ERR_PTR(-EINVAL);
 418
 419         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 420                 return ERR_PTR(-EINVAL);
 421
 422         if (tb[NFTA_META_DREG])
 423                 return &nft_meta_get_ops;
 424
 425         if (tb[NFTA_META_SREG])
 426                 return &nft_meta_set_ops;
 427
 428         return ERR_PTR(-EINVAL);
 429 }
 430
 431 static struct nft_expr_type nft_meta_type __read_mostly = {
 432         .name           = "meta",
 433         .select_ops     = &nft_meta_select_ops,
 434         .policy         = nft_meta_policy,
 435         .maxattr        = NFTA_META_MAX,
 436         .owner          = THIS_MODULE,
 437 };
 438
 439 static int __init nft_meta_module_init(void)
 440 {
 441         return nft_register_expr(&nft_meta_type);
 442 }
 443
 444 static void __exit nft_meta_module_exit(void)
 445 {
 446         nft_unregister_expr(&nft_meta_type);
 447 }
 448
 449 module_init(nft_meta_module_init);
 450 module_exit(nft_meta_module_exit);
 451
 452 MODULE_LICENSE("GPL");
 453 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 454 MODULE_ALIAS_NFT_EXPR("meta");