net/netfilter/nft_lookup.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
   4  *
   5  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/init.h>
  10 #include <linux/list.h>
  11 #include <linux/rbtree.h>
  12 #include <linux/netlink.h>
  13 #include <linux/netfilter.h>
  14 #include <linux/netfilter/nf_tables.h>
  15 #include <net/netfilter/nf_tables.h>
  16 #include <net/netfilter/nf_tables_core.h>
  17
  18 struct nft_lookup {
  19         struct nft_set                  *set;
  20         enum nft_registers              sreg:8;
  21         enum nft_registers              dreg:8;
  22         bool                            invert;
  23         struct nft_set_binding          binding;
  24 };
  25
  26 void nft_lookup_eval(const struct nft_expr *expr,
  27                      struct nft_regs *regs,
  28                      const struct nft_pktinfo *pkt)
  29 {
  30         const struct nft_lookup *priv = nft_expr_priv(expr);
  31         const struct nft_set *set = priv->set;
  32         const struct nft_set_ext *ext;
  33         bool found;
  34
  35         found = set->ops->lookup(nft_net(pkt), set, &regs->data[priv->sreg],
  36                                  &ext) ^ priv->invert;
  37         if (!found) {
  38                 regs->verdict.code = NFT_BREAK;
  39                 return;
  40         }
  41
  42         if (set->flags & NFT_SET_MAP)
  43                 nft_data_copy(&regs->data[priv->dreg],
  44                               nft_set_ext_data(ext), set->dlen);
  45
  46         nft_set_elem_update_expr(ext, regs, pkt);
  47 }
  48
  49 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
  50         [NFTA_LOOKUP_SET]       = { .type = NLA_STRING,
  51                                     .len = NFT_SET_MAXNAMELEN - 1 },
  52         [NFTA_LOOKUP_SET_ID]    = { .type = NLA_U32 },
  53         [NFTA_LOOKUP_SREG]      = { .type = NLA_U32 },
  54         [NFTA_LOOKUP_DREG]      = { .type = NLA_U32 },
  55         [NFTA_LOOKUP_FLAGS]     = { .type = NLA_U32 },
  56 };
  57
  58 static int nft_lookup_init(const struct nft_ctx *ctx,
  59                            const struct nft_expr *expr,
  60                            const struct nlattr * const tb[])
  61 {
  62         struct nft_lookup *priv = nft_expr_priv(expr);
  63         u8 genmask = nft_genmask_next(ctx->net);
  64         struct nft_set *set;
  65         u32 flags;
  66         int err;
  67
  68         if (tb[NFTA_LOOKUP_SET] == NULL ||
  69             tb[NFTA_LOOKUP_SREG] == NULL)
  70                 return -EINVAL;
  71
  72         set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
  73                                     tb[NFTA_LOOKUP_SET_ID], genmask);
  74         if (IS_ERR(set))
  75                 return PTR_ERR(set);
  76
  77         priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]);
  78         err = nft_validate_register_load(priv->sreg, set->klen);
  79         if (err < 0)
  80                 return err;
  81
  82         if (tb[NFTA_LOOKUP_FLAGS]) {
  83                 flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
  84
  85                 if (flags & ~NFT_LOOKUP_F_INV)
  86                         return -EINVAL;
  87
  88                 if (flags & NFT_LOOKUP_F_INV) {
  89                         if (set->flags & NFT_SET_MAP)
  90                                 return -EINVAL;
  91                         priv->invert = true;
  92                 }
  93         }
  94
  95         if (tb[NFTA_LOOKUP_DREG] != NULL) {
  96                 if (priv->invert)
  97                         return -EINVAL;
  98                 if (!(set->flags & NFT_SET_MAP))
  99                         return -EINVAL;
 100
 101                 priv->dreg = nft_parse_register(tb[NFTA_LOOKUP_DREG]);
 102                 err = nft_validate_register_store(ctx, priv->dreg, NULL,
 103                                                   set->dtype, set->dlen);
 104                 if (err < 0)
 105                         return err;
 106         } else if (set->flags & NFT_SET_MAP)
 107                 return -EINVAL;
 108
 109         priv->binding.flags = set->flags & NFT_SET_MAP;
 110
 111         err = nf_tables_bind_set(ctx, set, &priv->binding);
 112         if (err < 0)
 113                 return err;
 114
 115         priv->set = set;
 116         return 0;
 117 }
 118
 119 static void nft_lookup_deactivate(const struct nft_ctx *ctx,
 120                                   const struct nft_expr *expr,
 121                                   enum nft_trans_phase phase)
 122 {
 123         struct nft_lookup *priv = nft_expr_priv(expr);
 124
 125         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 126 }
 127
 128 static void nft_lookup_activate(const struct nft_ctx *ctx,
 129                                 const struct nft_expr *expr)
 130 {
 131         struct nft_lookup *priv = nft_expr_priv(expr);
 132
 133         priv->set->use++;
 134 }
 135
 136 static void nft_lookup_destroy(const struct nft_ctx *ctx,
 137                                const struct nft_expr *expr)
 138 {
 139         struct nft_lookup *priv = nft_expr_priv(expr);
 140
 141         nf_tables_destroy_set(ctx, priv->set);
 142 }
 143
 144 static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
 145 {
 146         const struct nft_lookup *priv = nft_expr_priv(expr);
 147         u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
 148
 149         if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
 150                 goto nla_put_failure;
 151         if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
 152                 goto nla_put_failure;
 153         if (priv->set->flags & NFT_SET_MAP)
 154                 if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
 155                         goto nla_put_failure;
 156         if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
 157                 goto nla_put_failure;
 158         return 0;
 159
 160 nla_put_failure:
 161         return -1;
 162 }
 163
 164 static int nft_lookup_validate_setelem(const struct nft_ctx *ctx,
 165                                        struct nft_set *set,
 166                                        const struct nft_set_iter *iter,
 167                                        struct nft_set_elem *elem)
 168 {
 169         const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv);
 170         struct nft_ctx *pctx = (struct nft_ctx *)ctx;
 171         const struct nft_data *data;
 172         int err;
 173
 174         if (nft_set_ext_exists(ext, NFT_SET_EXT_FLAGS) &&
 175             *nft_set_ext_flags(ext) & NFT_SET_ELEM_INTERVAL_END)
 176                 return 0;
 177
 178         data = nft_set_ext_data(ext);
 179         switch (data->verdict.code) {
 180         case NFT_JUMP:
 181         case NFT_GOTO:
 182                 pctx->level++;
 183                 err = nft_chain_validate(ctx, data->verdict.chain);
 184                 if (err < 0)
 185                         return err;
 186                 pctx->level--;
 187                 break;
 188         default:
 189                 break;
 190         }
 191
 192         return 0;
 193 }
 194
 195 static int nft_lookup_validate(const struct nft_ctx *ctx,
 196                                const struct nft_expr *expr,
 197                                const struct nft_data **d)
 198 {
 199         const struct nft_lookup *priv = nft_expr_priv(expr);
 200         struct nft_set_iter iter;
 201
 202         if (!(priv->set->flags & NFT_SET_MAP) ||
 203             priv->set->dtype != NFT_DATA_VERDICT)
 204                 return 0;
 205
 206         iter.genmask    = nft_genmask_next(ctx->net);
 207         iter.skip       = 0;
 208         iter.count      = 0;
 209         iter.err        = 0;
 210         iter.fn         = nft_lookup_validate_setelem;
 211
 212         priv->set->ops->walk(ctx, priv->set, &iter);
 213         if (iter.err < 0)
 214                 return iter.err;
 215
 216         return 0;
 217 }
 218
 219 static const struct nft_expr_ops nft_lookup_ops = {
 220         .type           = &nft_lookup_type,
 221         .size           = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
 222         .eval           = nft_lookup_eval,
 223         .init           = nft_lookup_init,
 224         .activate       = nft_lookup_activate,
 225         .deactivate     = nft_lookup_deactivate,
 226         .destroy        = nft_lookup_destroy,
 227         .dump           = nft_lookup_dump,
 228         .validate       = nft_lookup_validate,
 229 };
 230
 231 struct nft_expr_type nft_lookup_type __read_mostly = {
 232         .name           = "lookup",
 233         .ops            = &nft_lookup_ops,
 234         .policy         = nft_lookup_policy,
 235         .maxattr        = NFTA_LOOKUP_MAX,
 236         .owner          = THIS_MODULE,
 237 };