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 <net/dst.h>
  18 #include <net/sock.h>
  19 #include <net/tcp_states.h> /* for TCP_TIME_WAIT */
  20 #include <net/netfilter/nf_tables.h>
  21
  22 struct nft_meta {
  23         enum nft_meta_keys      key:8;
  24         union {
  25                 enum nft_registers      dreg:8;
  26                 enum nft_registers      sreg:8;
  27         };
  28 };
  29
  30 static void nft_meta_get_eval(const struct nft_expr *expr,
  31                               struct nft_data data[NFT_REG_MAX + 1],
  32                               const struct nft_pktinfo *pkt)
  33 {
  34         const struct nft_meta *priv = nft_expr_priv(expr);
  35         const struct sk_buff *skb = pkt->skb;
  36         const struct net_device *in = pkt->in, *out = pkt->out;
  37         struct nft_data *dest = &data[priv->dreg];
  38
  39         switch (priv->key) {
  40         case NFT_META_LEN:
  41                 dest->data[0] = skb->len;
  42                 break;
  43         case NFT_META_PROTOCOL:
  44                 *(__be16 *)dest->data = skb->protocol;
  45                 break;
  46         case NFT_META_NFPROTO:
  47                 dest->data[0] = pkt->ops->pf;
  48                 break;
  49         case NFT_META_L4PROTO:
  50                 dest->data[0] = pkt->tprot;
  51                 break;
  52         case NFT_META_PRIORITY:
  53                 dest->data[0] = skb->priority;
  54                 break;
  55         case NFT_META_MARK:
  56                 dest->data[0] = skb->mark;
  57                 break;
  58         case NFT_META_IIF:
  59                 if (in == NULL)
  60                         goto err;
  61                 dest->data[0] = in->ifindex;
  62                 break;
  63         case NFT_META_OIF:
  64                 if (out == NULL)
  65                         goto err;
  66                 dest->data[0] = out->ifindex;
  67                 break;
  68         case NFT_META_IIFNAME:
  69                 if (in == NULL)
  70                         goto err;
  71                 strncpy((char *)dest->data, in->name, sizeof(dest->data));
  72                 break;
  73         case NFT_META_OIFNAME:
  74                 if (out == NULL)
  75                         goto err;
  76                 strncpy((char *)dest->data, out->name, sizeof(dest->data));
  77                 break;
  78         case NFT_META_IIFTYPE:
  79                 if (in == NULL)
  80                         goto err;
  81                 *(u16 *)dest->data = in->type;
  82                 break;
  83         case NFT_META_OIFTYPE:
  84                 if (out == NULL)
  85                         goto err;
  86                 *(u16 *)dest->data = out->type;
  87                 break;
  88         case NFT_META_SKUID:
  89                 if (skb->sk == NULL || skb->sk->sk_state == TCP_TIME_WAIT)
  90                         goto err;
  91
  92                 read_lock_bh(&skb->sk->sk_callback_lock);
  93                 if (skb->sk->sk_socket == NULL ||
  94                     skb->sk->sk_socket->file == NULL) {
  95                         read_unlock_bh(&skb->sk->sk_callback_lock);
  96                         goto err;
  97                 }
  98
  99                 dest->data[0] =
 100                         from_kuid_munged(&init_user_ns,
 101                                 skb->sk->sk_socket->file->f_cred->fsuid);
 102                 read_unlock_bh(&skb->sk->sk_callback_lock);
 103                 break;
 104         case NFT_META_SKGID:
 105                 if (skb->sk == NULL || skb->sk->sk_state == TCP_TIME_WAIT)
 106                         goto err;
 107
 108                 read_lock_bh(&skb->sk->sk_callback_lock);
 109                 if (skb->sk->sk_socket == NULL ||
 110                     skb->sk->sk_socket->file == NULL) {
 111                         read_unlock_bh(&skb->sk->sk_callback_lock);
 112                         goto err;
 113                 }
 114                 dest->data[0] =
 115                         from_kgid_munged(&init_user_ns,
 116                                  skb->sk->sk_socket->file->f_cred->fsgid);
 117                 read_unlock_bh(&skb->sk->sk_callback_lock);
 118                 break;
 119 #ifdef CONFIG_NET_CLS_ROUTE
 120         case NFT_META_RTCLASSID: {
 121                 const struct dst_entry *dst = skb_dst(skb);
 122
 123                 if (dst == NULL)
 124                         goto err;
 125                 dest->data[0] = dst->tclassid;
 126                 break;
 127         }
 128 #endif
 129 #ifdef CONFIG_NETWORK_SECMARK
 130         case NFT_META_SECMARK:
 131                 dest->data[0] = skb->secmark;
 132                 break;
 133 #endif
 134         default:
 135                 WARN_ON(1);
 136                 goto err;
 137         }
 138         return;
 139
 140 err:
 141         data[NFT_REG_VERDICT].verdict = NFT_BREAK;
 142 }
 143
 144 static void nft_meta_set_eval(const struct nft_expr *expr,
 145                               struct nft_data data[NFT_REG_MAX + 1],
 146                               const struct nft_pktinfo *pkt)
 147 {
 148         const struct nft_meta *meta = nft_expr_priv(expr);
 149         struct sk_buff *skb = pkt->skb;
 150         u32 value = data[meta->sreg].data[0];
 151
 152         switch (meta->key) {
 153         case NFT_META_MARK:
 154                 skb->mark = value;
 155                 break;
 156         case NFT_META_PRIORITY:
 157                 skb->priority = value;
 158                 break;
 159         case NFT_META_NFTRACE:
 160                 skb->nf_trace = 1;
 161                 break;
 162         default:
 163                 WARN_ON(1);
 164         }
 165 }
 166
 167 static const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 168         [NFTA_META_DREG]        = { .type = NLA_U32 },
 169         [NFTA_META_KEY]         = { .type = NLA_U32 },
 170         [NFTA_META_SREG]        = { .type = NLA_U32 },
 171 };
 172
 173 static int nft_meta_init_validate_set(uint32_t key)
 174 {
 175         switch (key) {
 176         case NFT_META_MARK:
 177         case NFT_META_PRIORITY:
 178         case NFT_META_NFTRACE:
 179                 return 0;
 180         default:
 181                 return -EOPNOTSUPP;
 182         }
 183 }
 184
 185 static int nft_meta_init_validate_get(uint32_t key)
 186 {
 187         switch (key) {
 188         case NFT_META_LEN:
 189         case NFT_META_PROTOCOL:
 190         case NFT_META_NFPROTO:
 191         case NFT_META_L4PROTO:
 192         case NFT_META_PRIORITY:
 193         case NFT_META_MARK:
 194         case NFT_META_IIF:
 195         case NFT_META_OIF:
 196         case NFT_META_IIFNAME:
 197         case NFT_META_OIFNAME:
 198         case NFT_META_IIFTYPE:
 199         case NFT_META_OIFTYPE:
 200         case NFT_META_SKUID:
 201         case NFT_META_SKGID:
 202 #ifdef CONFIG_NET_CLS_ROUTE
 203         case NFT_META_RTCLASSID:
 204 #endif
 205 #ifdef CONFIG_NETWORK_SECMARK
 206         case NFT_META_SECMARK:
 207 #endif
 208                 return 0;
 209         default:
 210                 return -EOPNOTSUPP;
 211         }
 212
 213 }
 214
 215 static int nft_meta_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 216                          const struct nlattr * const tb[])
 217 {
 218         struct nft_meta *priv = nft_expr_priv(expr);
 219         int err;
 220
 221         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 222
 223         if (tb[NFTA_META_DREG]) {
 224                 err = nft_meta_init_validate_get(priv->key);
 225                 if (err < 0)
 226                         return err;
 227
 228                 priv->dreg = ntohl(nla_get_be32(tb[NFTA_META_DREG]));
 229                 err = nft_validate_output_register(priv->dreg);
 230                 if (err < 0)
 231                         return err;
 232
 233                 return nft_validate_data_load(ctx, priv->dreg, NULL,
 234                                               NFT_DATA_VALUE);
 235         }
 236
 237         err = nft_meta_init_validate_set(priv->key);
 238         if (err < 0)
 239                 return err;
 240
 241         priv->sreg = ntohl(nla_get_be32(tb[NFTA_META_SREG]));
 242         err = nft_validate_input_register(priv->sreg);
 243         if (err < 0)
 244                 return err;
 245
 246         return 0;
 247 }
 248
 249 static int nft_meta_get_dump(struct sk_buff *skb,
 250                              const struct nft_expr *expr)
 251 {
 252         const struct nft_meta *priv = nft_expr_priv(expr);
 253
 254         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 255                 goto nla_put_failure;
 256         if (nla_put_be32(skb, NFTA_META_DREG, htonl(priv->dreg)))
 257                 goto nla_put_failure;
 258         return 0;
 259
 260 nla_put_failure:
 261         return -1;
 262 }
 263
 264 static int nft_meta_set_dump(struct sk_buff *skb,
 265                              const struct nft_expr *expr)
 266 {
 267         const struct nft_meta *priv = nft_expr_priv(expr);
 268
 269         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 270                 goto nla_put_failure;
 271         if (nla_put_be32(skb, NFTA_META_SREG, htonl(priv->sreg)))
 272                 goto nla_put_failure;
 273
 274         return 0;
 275
 276 nla_put_failure:
 277         return -1;
 278 }
 279
 280 static struct nft_expr_type nft_meta_type;
 281 static const struct nft_expr_ops nft_meta_get_ops = {
 282         .type           = &nft_meta_type,
 283         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 284         .eval           = nft_meta_get_eval,
 285         .init           = nft_meta_init,
 286         .dump           = nft_meta_get_dump,
 287 };
 288
 289 static const struct nft_expr_ops nft_meta_set_ops = {
 290         .type           = &nft_meta_type,
 291         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 292         .eval           = nft_meta_set_eval,
 293         .init           = nft_meta_init,
 294         .dump           = nft_meta_set_dump,
 295 };
 296
 297 static const struct nft_expr_ops *
 298 nft_meta_select_ops(const struct nft_ctx *ctx,
 299                     const struct nlattr * const tb[])
 300 {
 301         if (tb[NFTA_META_KEY] == NULL)
 302                 return ERR_PTR(-EINVAL);
 303
 304         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 305                 return ERR_PTR(-EINVAL);
 306
 307         if (tb[NFTA_META_DREG])
 308                 return &nft_meta_get_ops;
 309
 310         if (tb[NFTA_META_SREG])
 311                 return &nft_meta_set_ops;
 312
 313         return ERR_PTR(-EINVAL);
 314 }
 315
 316 static struct nft_expr_type nft_meta_type __read_mostly = {
 317         .name           = "meta",
 318         .select_ops     = &nft_meta_select_ops,
 319         .policy         = nft_meta_policy,
 320         .maxattr        = NFTA_META_MAX,
 321         .owner          = THIS_MODULE,
 322 };
 323
 324 static int __init nft_meta_module_init(void)
 325 {
 326         return nft_register_expr(&nft_meta_type);
 327 }
 328
 329 static void __exit nft_meta_module_exit(void)
 330 {
 331         nft_unregister_expr(&nft_meta_type);
 332 }
 333
 334 module_init(nft_meta_module_init);
 335 module_exit(nft_meta_module_exit);
 336
 337 MODULE_LICENSE("GPL");
 338 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 339 MODULE_ALIAS_NFT_EXPR("meta");