net/netfilter/nft_objref.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2012-2016 Pablo Neira Ayuso <pablo@netfilter.org>
   4  */
   5
   6 #include <linux/init.h>
   7 #include <linux/module.h>
   8 #include <linux/skbuff.h>
   9 #include <linux/netlink.h>
  10 #include <linux/netfilter.h>
  11 #include <linux/netfilter/nf_tables.h>
  12 #include <net/netfilter/nf_tables_core.h>
  13
  14 #define nft_objref_priv(expr)   *((struct nft_object **)nft_expr_priv(expr))
  15
  16 void nft_objref_eval(const struct nft_expr *expr,
  17                      struct nft_regs *regs,
  18                      const struct nft_pktinfo *pkt)
  19 {
  20         struct nft_object *obj = nft_objref_priv(expr);
  21
  22         obj->ops->eval(obj, regs, pkt);
  23 }
  24
  25 static int nft_objref_init(const struct nft_ctx *ctx,
  26                            const struct nft_expr *expr,
  27                            const struct nlattr * const tb[])
  28 {
  29         struct nft_object *obj = nft_objref_priv(expr);
  30         u8 genmask = nft_genmask_next(ctx->net);
  31         u32 objtype;
  32
  33         if (!tb[NFTA_OBJREF_IMM_NAME] ||
  34             !tb[NFTA_OBJREF_IMM_TYPE])
  35                 return -EINVAL;
  36
  37         objtype = ntohl(nla_get_be32(tb[NFTA_OBJREF_IMM_TYPE]));
  38         obj = nft_obj_lookup(ctx->net, ctx->table,
  39                              tb[NFTA_OBJREF_IMM_NAME], objtype,
  40                              genmask);
  41         if (IS_ERR(obj))
  42                 return -ENOENT;
  43
  44         if (!nft_use_inc(&obj->use))
  45                 return -EMFILE;
  46
  47         nft_objref_priv(expr) = obj;
  48
  49         return 0;
  50 }
  51
  52 static int nft_objref_dump(struct sk_buff *skb,
  53                            const struct nft_expr *expr, bool reset)
  54 {
  55         const struct nft_object *obj = nft_objref_priv(expr);
  56
  57         if (nla_put_string(skb, NFTA_OBJREF_IMM_NAME, obj->key.name) ||
  58             nla_put_be32(skb, NFTA_OBJREF_IMM_TYPE,
  59                          htonl(obj->ops->type->type)))
  60                 goto nla_put_failure;
  61
  62         return 0;
  63
  64 nla_put_failure:
  65         return -1;
  66 }
  67
  68 static void nft_objref_deactivate(const struct nft_ctx *ctx,
  69                                   const struct nft_expr *expr,
  70                                   enum nft_trans_phase phase)
  71 {
  72         struct nft_object *obj = nft_objref_priv(expr);
  73
  74         if (phase == NFT_TRANS_COMMIT)
  75                 return;
  76
  77         nft_use_dec(&obj->use);
  78 }
  79
  80 static void nft_objref_activate(const struct nft_ctx *ctx,
  81                                 const struct nft_expr *expr)
  82 {
  83         struct nft_object *obj = nft_objref_priv(expr);
  84
  85         nft_use_inc_restore(&obj->use);
  86 }
  87
  88 static const struct nft_expr_ops nft_objref_ops = {
  89         .type           = &nft_objref_type,
  90         .size           = NFT_EXPR_SIZE(sizeof(struct nft_object *)),
  91         .eval           = nft_objref_eval,
  92         .init           = nft_objref_init,
  93         .activate       = nft_objref_activate,
  94         .deactivate     = nft_objref_deactivate,
  95         .dump           = nft_objref_dump,
  96         .reduce         = NFT_REDUCE_READONLY,
  97 };
  98
  99 struct nft_objref_map {
 100         struct nft_set          *set;
 101         u8                      sreg;
 102         struct nft_set_binding  binding;
 103 };
 104
 105 void nft_objref_map_eval(const struct nft_expr *expr,
 106                          struct nft_regs *regs,
 107                          const struct nft_pktinfo *pkt)
 108 {
 109         struct nft_objref_map *priv = nft_expr_priv(expr);
 110         const struct nft_set *set = priv->set;
 111         struct net *net = nft_net(pkt);
 112         const struct nft_set_ext *ext;
 113         struct nft_object *obj;
 114         bool found;
 115
 116         found = nft_set_do_lookup(net, set, &regs->data[priv->sreg], &ext);
 117         if (!found) {
 118                 ext = nft_set_catchall_lookup(net, set);
 119                 if (!ext) {
 120                         regs->verdict.code = NFT_BREAK;
 121                         return;
 122                 }
 123         }
 124         obj = *nft_set_ext_obj(ext);
 125         obj->ops->eval(obj, regs, pkt);
 126 }
 127
 128 static int nft_objref_map_init(const struct nft_ctx *ctx,
 129                                const struct nft_expr *expr,
 130                                const struct nlattr * const tb[])
 131 {
 132         struct nft_objref_map *priv = nft_expr_priv(expr);
 133         u8 genmask = nft_genmask_next(ctx->net);
 134         struct nft_set *set;
 135         int err;
 136
 137         set = nft_set_lookup_global(ctx->net, ctx->table,
 138                                     tb[NFTA_OBJREF_SET_NAME],
 139                                     tb[NFTA_OBJREF_SET_ID], genmask);
 140         if (IS_ERR(set))
 141                 return PTR_ERR(set);
 142
 143         if (!(set->flags & NFT_SET_OBJECT))
 144                 return -EINVAL;
 145
 146         err = nft_parse_register_load(ctx, tb[NFTA_OBJREF_SET_SREG], &priv->sreg,
 147                                       set->klen);
 148         if (err < 0)
 149                 return err;
 150
 151         priv->binding.flags = set->flags & NFT_SET_OBJECT;
 152
 153         err = nf_tables_bind_set(ctx, set, &priv->binding);
 154         if (err < 0)
 155                 return err;
 156
 157         priv->set = set;
 158         return 0;
 159 }
 160
 161 static int nft_objref_map_dump(struct sk_buff *skb,
 162                                const struct nft_expr *expr, bool reset)
 163 {
 164         const struct nft_objref_map *priv = nft_expr_priv(expr);
 165
 166         if (nft_dump_register(skb, NFTA_OBJREF_SET_SREG, priv->sreg) ||
 167             nla_put_string(skb, NFTA_OBJREF_SET_NAME, priv->set->name))
 168                 goto nla_put_failure;
 169
 170         return 0;
 171
 172 nla_put_failure:
 173         return -1;
 174 }
 175
 176 static void nft_objref_map_deactivate(const struct nft_ctx *ctx,
 177                                       const struct nft_expr *expr,
 178                                       enum nft_trans_phase phase)
 179 {
 180         struct nft_objref_map *priv = nft_expr_priv(expr);
 181
 182         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 183 }
 184
 185 static void nft_objref_map_activate(const struct nft_ctx *ctx,
 186                                     const struct nft_expr *expr)
 187 {
 188         struct nft_objref_map *priv = nft_expr_priv(expr);
 189
 190         nf_tables_activate_set(ctx, priv->set);
 191 }
 192
 193 static void nft_objref_map_destroy(const struct nft_ctx *ctx,
 194                                    const struct nft_expr *expr)
 195 {
 196         struct nft_objref_map *priv = nft_expr_priv(expr);
 197
 198         nf_tables_destroy_set(ctx, priv->set);
 199 }
 200
 201 static const struct nft_expr_ops nft_objref_map_ops = {
 202         .type           = &nft_objref_type,
 203         .size           = NFT_EXPR_SIZE(sizeof(struct nft_objref_map)),
 204         .eval           = nft_objref_map_eval,
 205         .init           = nft_objref_map_init,
 206         .activate       = nft_objref_map_activate,
 207         .deactivate     = nft_objref_map_deactivate,
 208         .destroy        = nft_objref_map_destroy,
 209         .dump           = nft_objref_map_dump,
 210         .reduce         = NFT_REDUCE_READONLY,
 211 };
 212
 213 static const struct nft_expr_ops *
 214 nft_objref_select_ops(const struct nft_ctx *ctx,
 215                       const struct nlattr * const tb[])
 216 {
 217         if (tb[NFTA_OBJREF_SET_SREG] &&
 218             (tb[NFTA_OBJREF_SET_NAME] ||
 219              tb[NFTA_OBJREF_SET_ID]))
 220                 return &nft_objref_map_ops;
 221         else if (tb[NFTA_OBJREF_IMM_NAME] &&
 222                  tb[NFTA_OBJREF_IMM_TYPE])
 223                 return &nft_objref_ops;
 224
 225         return ERR_PTR(-EOPNOTSUPP);
 226 }
 227
 228 static const struct nla_policy nft_objref_policy[NFTA_OBJREF_MAX + 1] = {
 229         [NFTA_OBJREF_IMM_NAME]  = { .type = NLA_STRING,
 230                                     .len = NFT_OBJ_MAXNAMELEN - 1 },
 231         [NFTA_OBJREF_IMM_TYPE]  = { .type = NLA_U32 },
 232         [NFTA_OBJREF_SET_SREG]  = { .type = NLA_U32 },
 233         [NFTA_OBJREF_SET_NAME]  = { .type = NLA_STRING,
 234                                     .len = NFT_SET_MAXNAMELEN - 1 },
 235         [NFTA_OBJREF_SET_ID]    = { .type = NLA_U32 },
 236 };
 237
 238 struct nft_expr_type nft_objref_type __read_mostly = {
 239         .name           = "objref",
 240         .select_ops     = nft_objref_select_ops,
 241         .policy         = nft_objref_policy,
 242         .maxattr        = NFTA_OBJREF_MAX,
 243         .owner          = THIS_MODULE,
 244 };