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