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 void nft_meta_get_eval(const struct nft_expr *expr,
  32                        struct nft_regs *regs,
  33                        const struct nft_pktinfo *pkt)
  34 {
  35         const struct nft_meta *priv = nft_expr_priv(expr);
  36         const struct sk_buff *skb = pkt->skb;
  37         const struct net_device *in = pkt->in, *out = pkt->out;
  38         struct sock *sk;
  39         u32 *dest = &regs->data[priv->dreg];
  40
  41         switch (priv->key) {
  42         case NFT_META_LEN:
  43                 *dest = skb->len;
  44                 break;
  45         case NFT_META_PROTOCOL:
  46                 *dest = 0;
  47                 *(__be16 *)dest = skb->protocol;
  48                 break;
  49         case NFT_META_NFPROTO:
  50                 *dest = pkt->pf;
  51                 break;
  52         case NFT_META_L4PROTO:
  53                 *dest = pkt->tprot;
  54                 break;
  55         case NFT_META_PRIORITY:
  56                 *dest = skb->priority;
  57                 break;
  58         case NFT_META_MARK:
  59                 *dest = skb->mark;
  60                 break;
  61         case NFT_META_IIF:
  62                 if (in == NULL)
  63                         goto err;
  64                 *dest = in->ifindex;
  65                 break;
  66         case NFT_META_OIF:
  67                 if (out == NULL)
  68                         goto err;
  69                 *dest = out->ifindex;
  70                 break;
  71         case NFT_META_IIFNAME:
  72                 if (in == NULL)
  73                         goto err;
  74                 strncpy((char *)dest, in->name, IFNAMSIZ);
  75                 break;
  76         case NFT_META_OIFNAME:
  77                 if (out == NULL)
  78                         goto err;
  79                 strncpy((char *)dest, out->name, IFNAMSIZ);
  80                 break;
  81         case NFT_META_IIFTYPE:
  82                 if (in == NULL)
  83                         goto err;
  84                 *dest = 0;
  85                 *(u16 *)dest = in->type;
  86                 break;
  87         case NFT_META_OIFTYPE:
  88                 if (out == NULL)
  89                         goto err;
  90                 *dest = 0;
  91                 *(u16 *)dest = out->type;
  92                 break;
  93         case NFT_META_SKUID:
  94                 sk = skb_to_full_sk(skb);
  95                 if (!sk || !sk_fullsock(sk))
  96                         goto err;
  97
  98                 read_lock_bh(&sk->sk_callback_lock);
  99                 if (sk->sk_socket == NULL ||
 100                     sk->sk_socket->file == NULL) {
 101                         read_unlock_bh(&sk->sk_callback_lock);
 102                         goto err;
 103                 }
 104
 105                 *dest = from_kuid_munged(&init_user_ns,
 106                                 sk->sk_socket->file->f_cred->fsuid);
 107                 read_unlock_bh(&sk->sk_callback_lock);
 108                 break;
 109         case NFT_META_SKGID:
 110                 sk = skb_to_full_sk(skb);
 111                 if (!sk || !sk_fullsock(sk))
 112                         goto err;
 113
 114                 read_lock_bh(&sk->sk_callback_lock);
 115                 if (sk->sk_socket == NULL ||
 116                     sk->sk_socket->file == NULL) {
 117                         read_unlock_bh(&sk->sk_callback_lock);
 118                         goto err;
 119                 }
 120                 *dest = from_kgid_munged(&init_user_ns,
 121                                  sk->sk_socket->file->f_cred->fsgid);
 122                 read_unlock_bh(&sk->sk_callback_lock);
 123                 break;
 124 #ifdef CONFIG_IP_ROUTE_CLASSID
 125         case NFT_META_RTCLASSID: {
 126                 const struct dst_entry *dst = skb_dst(skb);
 127
 128                 if (dst == NULL)
 129                         goto err;
 130                 *dest = dst->tclassid;
 131                 break;
 132         }
 133 #endif
 134 #ifdef CONFIG_NETWORK_SECMARK
 135         case NFT_META_SECMARK:
 136                 *dest = skb->secmark;
 137                 break;
 138 #endif
 139         case NFT_META_PKTTYPE:
 140                 if (skb->pkt_type != PACKET_LOOPBACK) {
 141                         *dest = skb->pkt_type;
 142                         break;
 143                 }
 144
 145                 switch (pkt->pf) {
 146                 case NFPROTO_IPV4:
 147                         if (ipv4_is_multicast(ip_hdr(skb)->daddr))
 148                                 *dest = PACKET_MULTICAST;
 149                         else
 150                                 *dest = PACKET_BROADCAST;
 151                         break;
 152                 case NFPROTO_IPV6:
 153                         if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
 154                                 *dest = PACKET_MULTICAST;
 155                         else
 156                                 *dest = PACKET_BROADCAST;
 157                         break;
 158                 default:
 159                         WARN_ON(1);
 160                         goto err;
 161                 }
 162                 break;
 163         case NFT_META_CPU:
 164                 *dest = raw_smp_processor_id();
 165                 break;
 166         case NFT_META_IIFGROUP:
 167                 if (in == NULL)
 168                         goto err;
 169                 *dest = in->group;
 170                 break;
 171         case NFT_META_OIFGROUP:
 172                 if (out == NULL)
 173                         goto err;
 174                 *dest = out->group;
 175                 break;
 176 #ifdef CONFIG_CGROUP_NET_CLASSID
 177         case NFT_META_CGROUP:
 178                 sk = skb_to_full_sk(skb);
 179                 if (!sk || !sk_fullsock(sk))
 180                         goto err;
 181                 *dest = sock_cgroup_classid(&sk->sk_cgrp_data);
 182                 break;
 183 #endif
 184         default:
 185                 WARN_ON(1);
 186                 goto err;
 187         }
 188         return;
 189
 190 err:
 191         regs->verdict.code = NFT_BREAK;
 192 }
 193 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 194
 195 /* don't change or set _LOOPBACK, _USER, etc. */
 196 static bool pkt_type_ok(u32 p)
 197 {
 198         return p == PACKET_HOST || p == PACKET_BROADCAST ||
 199                p == PACKET_MULTICAST || p == PACKET_OTHERHOST;
 200 }
 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                     pkt_type_ok(value) && pkt_type_ok(skb->pkt_type))
 220                         skb->pkt_type = value;
 221                 break;
 222         case NFT_META_NFTRACE:
 223                 skb->nf_trace = 1;
 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         default:
 281                 return -EOPNOTSUPP;
 282         }
 283
 284         priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
 285         return nft_validate_register_store(ctx, priv->dreg, NULL,
 286                                            NFT_DATA_VALUE, len);
 287 }
 288 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 289
 290 static int nft_meta_set_init_pkttype(const struct nft_ctx *ctx)
 291 {
 292         unsigned int hooks;
 293
 294         switch (ctx->afi->family) {
 295         case NFPROTO_BRIDGE:
 296                 hooks = 1 << NF_BR_PRE_ROUTING;
 297                 break;
 298         case NFPROTO_NETDEV:
 299                 hooks = 1 << NF_NETDEV_INGRESS;
 300                 break;
 301         default:
 302                 return -EOPNOTSUPP;
 303         }
 304
 305         return nft_chain_validate_hooks(ctx->chain, hooks);
 306 }
 307
 308 int nft_meta_set_init(const struct nft_ctx *ctx,
 309                       const struct nft_expr *expr,
 310                       const struct nlattr * const tb[])
 311 {
 312         struct nft_meta *priv = nft_expr_priv(expr);
 313         unsigned int len;
 314         int err;
 315
 316         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 317         switch (priv->key) {
 318         case NFT_META_MARK:
 319         case NFT_META_PRIORITY:
 320                 len = sizeof(u32);
 321                 break;
 322         case NFT_META_NFTRACE:
 323                 len = sizeof(u8);
 324                 break;
 325         case NFT_META_PKTTYPE:
 326                 err = nft_meta_set_init_pkttype(ctx);
 327                 if (err)
 328                         return err;
 329                 len = sizeof(u8);
 330                 break;
 331         default:
 332                 return -EOPNOTSUPP;
 333         }
 334
 335         priv->sreg = nft_parse_register(tb[NFTA_META_SREG]);
 336         err = nft_validate_register_load(priv->sreg, len);
 337         if (err < 0)
 338                 return err;
 339
 340         if (priv->key == NFT_META_NFTRACE)
 341                 static_branch_inc(&nft_trace_enabled);
 342
 343         return 0;
 344 }
 345 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 346
 347 int nft_meta_get_dump(struct sk_buff *skb,
 348                       const struct nft_expr *expr)
 349 {
 350         const struct nft_meta *priv = nft_expr_priv(expr);
 351
 352         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 353                 goto nla_put_failure;
 354         if (nft_dump_register(skb, NFTA_META_DREG, priv->dreg))
 355                 goto nla_put_failure;
 356         return 0;
 357
 358 nla_put_failure:
 359         return -1;
 360 }
 361 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 362
 363 int nft_meta_set_dump(struct sk_buff *skb,
 364                       const struct nft_expr *expr)
 365 {
 366         const struct nft_meta *priv = nft_expr_priv(expr);
 367
 368         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 369                 goto nla_put_failure;
 370         if (nft_dump_register(skb, NFTA_META_SREG, priv->sreg))
 371                 goto nla_put_failure;
 372
 373         return 0;
 374
 375 nla_put_failure:
 376         return -1;
 377 }
 378 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 379
 380 void nft_meta_set_destroy(const struct nft_ctx *ctx,
 381                           const struct nft_expr *expr)
 382 {
 383         const struct nft_meta *priv = nft_expr_priv(expr);
 384
 385         if (priv->key == NFT_META_NFTRACE)
 386                 static_branch_dec(&nft_trace_enabled);
 387 }
 388 EXPORT_SYMBOL_GPL(nft_meta_set_destroy);
 389
 390 static struct nft_expr_type nft_meta_type;
 391 static const struct nft_expr_ops nft_meta_get_ops = {
 392         .type           = &nft_meta_type,
 393         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 394         .eval           = nft_meta_get_eval,
 395         .init           = nft_meta_get_init,
 396         .dump           = nft_meta_get_dump,
 397 };
 398
 399 static const struct nft_expr_ops nft_meta_set_ops = {
 400         .type           = &nft_meta_type,
 401         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 402         .eval           = nft_meta_set_eval,
 403         .init           = nft_meta_set_init,
 404         .destroy        = nft_meta_set_destroy,
 405         .dump           = nft_meta_set_dump,
 406 };
 407
 408 static const struct nft_expr_ops *
 409 nft_meta_select_ops(const struct nft_ctx *ctx,
 410                     const struct nlattr * const tb[])
 411 {
 412         if (tb[NFTA_META_KEY] == NULL)
 413                 return ERR_PTR(-EINVAL);
 414
 415         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 416                 return ERR_PTR(-EINVAL);
 417
 418         if (tb[NFTA_META_DREG])
 419                 return &nft_meta_get_ops;
 420
 421         if (tb[NFTA_META_SREG])
 422                 return &nft_meta_set_ops;
 423
 424         return ERR_PTR(-EINVAL);
 425 }
 426
 427 static struct nft_expr_type nft_meta_type __read_mostly = {
 428         .name           = "meta",
 429         .select_ops     = &nft_meta_select_ops,
 430         .policy         = nft_meta_policy,
 431         .maxattr        = NFTA_META_MAX,
 432         .owner          = THIS_MODULE,
 433 };
 434
 435 static int __init nft_meta_module_init(void)
 436 {
 437         return nft_register_expr(&nft_meta_type);
 438 }
 439
 440 static void __exit nft_meta_module_exit(void)
 441 {
 442         nft_unregister_expr(&nft_meta_type);
 443 }
 444
 445 module_init(nft_meta_module_init);
 446 module_exit(nft_meta_module_exit);
 447
 448 MODULE_LICENSE("GPL");
 449 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 450 MODULE_ALIAS_NFT_EXPR("meta");