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 /* don't change or set _LOOPBACK, _USER, etc. */
 203 static bool pkt_type_ok(u32 p)
 204 {
 205         return p == PACKET_HOST || p == PACKET_BROADCAST ||
 206                p == PACKET_MULTICAST || p == PACKET_OTHERHOST;
 207 }
 208
 209 void nft_meta_set_eval(const struct nft_expr *expr,
 210                        struct nft_regs *regs,
 211                        const struct nft_pktinfo *pkt)
 212 {
 213         const struct nft_meta *meta = nft_expr_priv(expr);
 214         struct sk_buff *skb = pkt->skb;
 215         u32 value = regs->data[meta->sreg];
 216
 217         switch (meta->key) {
 218         case NFT_META_MARK:
 219                 skb->mark = value;
 220                 break;
 221         case NFT_META_PRIORITY:
 222                 skb->priority = value;
 223                 break;
 224         case NFT_META_PKTTYPE:
 225                 if (skb->pkt_type != value &&
 226                     pkt_type_ok(value) && pkt_type_ok(skb->pkt_type))
 227                         skb->pkt_type = value;
 228                 break;
 229         case NFT_META_NFTRACE:
 230                 skb->nf_trace = 1;
 231                 break;
 232         default:
 233                 WARN_ON(1);
 234         }
 235 }
 236 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 237
 238 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 239         [NFTA_META_DREG]        = { .type = NLA_U32 },
 240         [NFTA_META_KEY]         = { .type = NLA_U32 },
 241         [NFTA_META_SREG]        = { .type = NLA_U32 },
 242 };
 243 EXPORT_SYMBOL_GPL(nft_meta_policy);
 244
 245 int nft_meta_get_init(const struct nft_ctx *ctx,
 246                       const struct nft_expr *expr,
 247                       const struct nlattr * const tb[])
 248 {
 249         struct nft_meta *priv = nft_expr_priv(expr);
 250         unsigned int len;
 251
 252         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 253         switch (priv->key) {
 254         case NFT_META_PROTOCOL:
 255         case NFT_META_IIFTYPE:
 256         case NFT_META_OIFTYPE:
 257                 len = sizeof(u16);
 258                 break;
 259         case NFT_META_NFPROTO:
 260         case NFT_META_L4PROTO:
 261         case NFT_META_LEN:
 262         case NFT_META_PRIORITY:
 263         case NFT_META_MARK:
 264         case NFT_META_IIF:
 265         case NFT_META_OIF:
 266         case NFT_META_SKUID:
 267         case NFT_META_SKGID:
 268 #ifdef CONFIG_IP_ROUTE_CLASSID
 269         case NFT_META_RTCLASSID:
 270 #endif
 271 #ifdef CONFIG_NETWORK_SECMARK
 272         case NFT_META_SECMARK:
 273 #endif
 274         case NFT_META_PKTTYPE:
 275         case NFT_META_CPU:
 276         case NFT_META_IIFGROUP:
 277         case NFT_META_OIFGROUP:
 278 #ifdef CONFIG_CGROUP_NET_CLASSID
 279         case NFT_META_CGROUP:
 280 #endif
 281                 len = sizeof(u32);
 282                 break;
 283         case NFT_META_IIFNAME:
 284         case NFT_META_OIFNAME:
 285                 len = IFNAMSIZ;
 286                 break;
 287         case NFT_META_PRANDOM:
 288                 prandom_init_once(&nft_prandom_state);
 289                 len = sizeof(u32);
 290                 break;
 291         default:
 292                 return -EOPNOTSUPP;
 293         }
 294
 295         priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
 296         return nft_validate_register_store(ctx, priv->dreg, NULL,
 297                                            NFT_DATA_VALUE, len);
 298 }
 299 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 300
 301 static int nft_meta_set_init_pkttype(const struct nft_ctx *ctx)
 302 {
 303         unsigned int hooks;
 304
 305         switch (ctx->afi->family) {
 306         case NFPROTO_BRIDGE:
 307                 hooks = 1 << NF_BR_PRE_ROUTING;
 308                 break;
 309         case NFPROTO_NETDEV:
 310                 hooks = 1 << NF_NETDEV_INGRESS;
 311                 break;
 312         default:
 313                 return -EOPNOTSUPP;
 314         }
 315
 316         return nft_chain_validate_hooks(ctx->chain, hooks);
 317 }
 318
 319 int nft_meta_set_init(const struct nft_ctx *ctx,
 320                       const struct nft_expr *expr,
 321                       const struct nlattr * const tb[])
 322 {
 323         struct nft_meta *priv = nft_expr_priv(expr);
 324         unsigned int len;
 325         int err;
 326
 327         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 328         switch (priv->key) {
 329         case NFT_META_MARK:
 330         case NFT_META_PRIORITY:
 331                 len = sizeof(u32);
 332                 break;
 333         case NFT_META_NFTRACE:
 334                 len = sizeof(u8);
 335                 break;
 336         case NFT_META_PKTTYPE:
 337                 err = nft_meta_set_init_pkttype(ctx);
 338                 if (err)
 339                         return err;
 340                 len = sizeof(u8);
 341                 break;
 342         default:
 343                 return -EOPNOTSUPP;
 344         }
 345
 346         priv->sreg = nft_parse_register(tb[NFTA_META_SREG]);
 347         err = nft_validate_register_load(priv->sreg, len);
 348         if (err < 0)
 349                 return err;
 350
 351         if (priv->key == NFT_META_NFTRACE)
 352                 static_branch_inc(&nft_trace_enabled);
 353
 354         return 0;
 355 }
 356 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 357
 358 int nft_meta_get_dump(struct sk_buff *skb,
 359                       const struct nft_expr *expr)
 360 {
 361         const struct nft_meta *priv = nft_expr_priv(expr);
 362
 363         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 364                 goto nla_put_failure;
 365         if (nft_dump_register(skb, NFTA_META_DREG, priv->dreg))
 366                 goto nla_put_failure;
 367         return 0;
 368
 369 nla_put_failure:
 370         return -1;
 371 }
 372 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 373
 374 int nft_meta_set_dump(struct sk_buff *skb,
 375                       const struct nft_expr *expr)
 376 {
 377         const struct nft_meta *priv = nft_expr_priv(expr);
 378
 379         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 380                 goto nla_put_failure;
 381         if (nft_dump_register(skb, NFTA_META_SREG, priv->sreg))
 382                 goto nla_put_failure;
 383
 384         return 0;
 385
 386 nla_put_failure:
 387         return -1;
 388 }
 389 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 390
 391 void nft_meta_set_destroy(const struct nft_ctx *ctx,
 392                           const struct nft_expr *expr)
 393 {
 394         const struct nft_meta *priv = nft_expr_priv(expr);
 395
 396         if (priv->key == NFT_META_NFTRACE)
 397                 static_branch_dec(&nft_trace_enabled);
 398 }
 399 EXPORT_SYMBOL_GPL(nft_meta_set_destroy);
 400
 401 static struct nft_expr_type nft_meta_type;
 402 static const struct nft_expr_ops nft_meta_get_ops = {
 403         .type           = &nft_meta_type,
 404         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 405         .eval           = nft_meta_get_eval,
 406         .init           = nft_meta_get_init,
 407         .dump           = nft_meta_get_dump,
 408 };
 409
 410 static const struct nft_expr_ops nft_meta_set_ops = {
 411         .type           = &nft_meta_type,
 412         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 413         .eval           = nft_meta_set_eval,
 414         .init           = nft_meta_set_init,
 415         .destroy        = nft_meta_set_destroy,
 416         .dump           = nft_meta_set_dump,
 417 };
 418
 419 static const struct nft_expr_ops *
 420 nft_meta_select_ops(const struct nft_ctx *ctx,
 421                     const struct nlattr * const tb[])
 422 {
 423         if (tb[NFTA_META_KEY] == NULL)
 424                 return ERR_PTR(-EINVAL);
 425
 426         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 427                 return ERR_PTR(-EINVAL);
 428
 429         if (tb[NFTA_META_DREG])
 430                 return &nft_meta_get_ops;
 431
 432         if (tb[NFTA_META_SREG])
 433                 return &nft_meta_set_ops;
 434
 435         return ERR_PTR(-EINVAL);
 436 }
 437
 438 static struct nft_expr_type nft_meta_type __read_mostly = {
 439         .name           = "meta",
 440         .select_ops     = &nft_meta_select_ops,
 441         .policy         = nft_meta_policy,
 442         .maxattr        = NFTA_META_MAX,
 443         .owner          = THIS_MODULE,
 444 };
 445
 446 static int __init nft_meta_module_init(void)
 447 {
 448         return nft_register_expr(&nft_meta_type);
 449 }
 450
 451 static void __exit nft_meta_module_exit(void)
 452 {
 453         nft_unregister_expr(&nft_meta_type);
 454 }
 455
 456 module_init(nft_meta_module_init);
 457 module_exit(nft_meta_module_exit);
 458
 459 MODULE_LICENSE("GPL");
 460 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 461 MODULE_ALIAS_NFT_EXPR("meta");