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         u8                              sreg;
  21         u8                              dreg;
  22         bool                            dreg_set;
  23         bool                            invert;
  24         struct nft_set_binding          binding;
  25 };
  26
  27 #ifdef CONFIG_MITIGATION_RETPOLINE
  28 bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
  29                        const u32 *key, const struct nft_set_ext **ext)
  30 {
  31         if (set->ops == &nft_set_hash_fast_type.ops)
  32                 return nft_hash_lookup_fast(net, set, key, ext);
  33         if (set->ops == &nft_set_hash_type.ops)
  34                 return nft_hash_lookup(net, set, key, ext);
  35
  36         if (set->ops == &nft_set_rhash_type.ops)
  37                 return nft_rhash_lookup(net, set, key, ext);
  38
  39         if (set->ops == &nft_set_bitmap_type.ops)
  40                 return nft_bitmap_lookup(net, set, key, ext);
  41
  42         if (set->ops == &nft_set_pipapo_type.ops)
  43                 return nft_pipapo_lookup(net, set, key, ext);
  44 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
  45         if (set->ops == &nft_set_pipapo_avx2_type.ops)
  46                 return nft_pipapo_avx2_lookup(net, set, key, ext);
  47 #endif
  48
  49         if (set->ops == &nft_set_rbtree_type.ops)
  50                 return nft_rbtree_lookup(net, set, key, ext);
  51
  52         WARN_ON_ONCE(1);
  53         return set->ops->lookup(net, set, key, ext);
  54 }
  55 EXPORT_SYMBOL_GPL(nft_set_do_lookup);
  56 #endif
  57
  58 void nft_lookup_eval(const struct nft_expr *expr,
  59                      struct nft_regs *regs,
  60                      const struct nft_pktinfo *pkt)
  61 {
  62         const struct nft_lookup *priv = nft_expr_priv(expr);
  63         const struct nft_set *set = priv->set;
  64         const struct nft_set_ext *ext = NULL;
  65         const struct net *net = nft_net(pkt);
  66         bool found;
  67
  68         found = nft_set_do_lookup(net, set, &regs->data[priv->sreg], &ext) ^
  69                                   priv->invert;
  70         if (!found) {
  71                 ext = nft_set_catchall_lookup(net, set);
  72                 if (!ext) {
  73                         regs->verdict.code = NFT_BREAK;
  74                         return;
  75                 }
  76         }
  77
  78         if (ext) {
  79                 if (priv->dreg_set)
  80                         nft_data_copy(&regs->data[priv->dreg],
  81                                       nft_set_ext_data(ext), set->dlen);
  82
  83                 nft_set_elem_update_expr(ext, regs, pkt);
  84         }
  85 }
  86
  87 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
  88         [NFTA_LOOKUP_SET]       = { .type = NLA_STRING,
  89                                     .len = NFT_SET_MAXNAMELEN - 1 },
  90         [NFTA_LOOKUP_SET_ID]    = { .type = NLA_U32 },
  91         [NFTA_LOOKUP_SREG]      = { .type = NLA_U32 },
  92         [NFTA_LOOKUP_DREG]      = { .type = NLA_U32 },
  93         [NFTA_LOOKUP_FLAGS]     =
  94                 NLA_POLICY_MASK(NLA_BE32, NFT_LOOKUP_F_INV),
  95 };
  96
  97 static int nft_lookup_init(const struct nft_ctx *ctx,
  98                            const struct nft_expr *expr,
  99                            const struct nlattr * const tb[])
 100 {
 101         struct nft_lookup *priv = nft_expr_priv(expr);
 102         u8 genmask = nft_genmask_next(ctx->net);
 103         struct nft_set *set;
 104         u32 flags;
 105         int err;
 106
 107         if (tb[NFTA_LOOKUP_SET] == NULL ||
 108             tb[NFTA_LOOKUP_SREG] == NULL)
 109                 return -EINVAL;
 110
 111         set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
 112                                     tb[NFTA_LOOKUP_SET_ID], genmask);
 113         if (IS_ERR(set))
 114                 return PTR_ERR(set);
 115
 116         err = nft_parse_register_load(ctx, tb[NFTA_LOOKUP_SREG], &priv->sreg,
 117                                       set->klen);
 118         if (err < 0)
 119                 return err;
 120
 121         if (tb[NFTA_LOOKUP_FLAGS]) {
 122                 flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
 123
 124                 if (flags & NFT_LOOKUP_F_INV)
 125                         priv->invert = true;
 126         }
 127
 128         if (tb[NFTA_LOOKUP_DREG] != NULL) {
 129                 if (priv->invert)
 130                         return -EINVAL;
 131                 if (!(set->flags & NFT_SET_MAP))
 132                         return -EINVAL;
 133
 134                 err = nft_parse_register_store(ctx, tb[NFTA_LOOKUP_DREG],
 135                                                &priv->dreg, NULL,
 136                                                nft_set_datatype(set),
 137                                                set->dlen);
 138                 if (err < 0)
 139                         return err;
 140                 priv->dreg_set = true;
 141         } else if (set->flags & NFT_SET_MAP) {
 142                 /* Map given, but user asks for lookup only (i.e. to
 143                  * ignore value assoicated with key).
 144                  *
 145                  * This makes no sense for anonymous maps since they are
 146                  * scoped to the rule, but for named sets this can be useful.
 147                  */
 148                 if (set->flags & NFT_SET_ANONYMOUS)
 149                         return -EINVAL;
 150         }
 151
 152         priv->binding.flags = set->flags & NFT_SET_MAP;
 153
 154         err = nf_tables_bind_set(ctx, set, &priv->binding);
 155         if (err < 0)
 156                 return err;
 157
 158         priv->set = set;
 159         return 0;
 160 }
 161
 162 static void nft_lookup_deactivate(const struct nft_ctx *ctx,
 163                                   const struct nft_expr *expr,
 164                                   enum nft_trans_phase phase)
 165 {
 166         struct nft_lookup *priv = nft_expr_priv(expr);
 167
 168         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 169 }
 170
 171 static void nft_lookup_activate(const struct nft_ctx *ctx,
 172                                 const struct nft_expr *expr)
 173 {
 174         struct nft_lookup *priv = nft_expr_priv(expr);
 175
 176         nf_tables_activate_set(ctx, priv->set);
 177 }
 178
 179 static void nft_lookup_destroy(const struct nft_ctx *ctx,
 180                                const struct nft_expr *expr)
 181 {
 182         struct nft_lookup *priv = nft_expr_priv(expr);
 183
 184         nf_tables_destroy_set(ctx, priv->set);
 185 }
 186
 187 static int nft_lookup_dump(struct sk_buff *skb,
 188                            const struct nft_expr *expr, bool reset)
 189 {
 190         const struct nft_lookup *priv = nft_expr_priv(expr);
 191         u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
 192
 193         if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
 194                 goto nla_put_failure;
 195         if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
 196                 goto nla_put_failure;
 197         if (priv->dreg_set)
 198                 if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
 199                         goto nla_put_failure;
 200         if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
 201                 goto nla_put_failure;
 202         return 0;
 203
 204 nla_put_failure:
 205         return -1;
 206 }
 207
 208 static int nft_lookup_validate(const struct nft_ctx *ctx,
 209                                const struct nft_expr *expr)
 210 {
 211         const struct nft_lookup *priv = nft_expr_priv(expr);
 212         struct nft_set_iter iter;
 213
 214         if (!(priv->set->flags & NFT_SET_MAP) ||
 215             priv->set->dtype != NFT_DATA_VERDICT)
 216                 return 0;
 217
 218         iter.genmask    = nft_genmask_next(ctx->net);
 219         iter.type       = NFT_ITER_UPDATE;
 220         iter.skip       = 0;
 221         iter.count      = 0;
 222         iter.err        = 0;
 223         iter.fn         = nft_setelem_validate;
 224
 225         priv->set->ops->walk(ctx, priv->set, &iter);
 226         if (!iter.err)
 227                 iter.err = nft_set_catchall_validate(ctx, priv->set);
 228
 229         if (iter.err < 0)
 230                 return iter.err;
 231
 232         return 0;
 233 }
 234
 235 static bool nft_lookup_reduce(struct nft_regs_track *track,
 236                               const struct nft_expr *expr)
 237 {
 238         const struct nft_lookup *priv = nft_expr_priv(expr);
 239
 240         if (priv->set->flags & NFT_SET_MAP)
 241                 nft_reg_track_cancel(track, priv->dreg, priv->set->dlen);
 242
 243         return false;
 244 }
 245
 246 static const struct nft_expr_ops nft_lookup_ops = {
 247         .type           = &nft_lookup_type,
 248         .size           = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
 249         .eval           = nft_lookup_eval,
 250         .init           = nft_lookup_init,
 251         .activate       = nft_lookup_activate,
 252         .deactivate     = nft_lookup_deactivate,
 253         .destroy        = nft_lookup_destroy,
 254         .dump           = nft_lookup_dump,
 255         .validate       = nft_lookup_validate,
 256         .reduce         = nft_lookup_reduce,
 257 };
 258
 259 struct nft_expr_type nft_lookup_type __read_mostly = {
 260         .name           = "lookup",
 261         .ops            = &nft_lookup_ops,
 262         .policy         = nft_lookup_policy,
 263         .maxattr        = NFTA_LOOKUP_MAX,
 264         .owner          = THIS_MODULE,
 265 };