net/netfilter/nft_dynset.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2015 Patrick McHardy <kaber@trash.net>
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/netlink.h>
  10 #include <linux/netfilter.h>
  11 #include <linux/netfilter/nf_tables.h>
  12 #include <net/netfilter/nf_tables.h>
  13 #include <net/netfilter/nf_tables_core.h>
  14
  15 struct nft_dynset {
  16         struct nft_set                  *set;
  17         struct nft_set_ext_tmpl         tmpl;
  18         enum nft_dynset_ops             op:8;
  19         enum nft_registers              sreg_key:8;
  20         enum nft_registers              sreg_data:8;
  21         bool                            invert;
  22         u64                             timeout;
  23         struct nft_expr                 *expr;
  24         struct nft_set_binding          binding;
  25 };
  26
  27 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
  28                             struct nft_regs *regs)
  29 {
  30         const struct nft_dynset *priv = nft_expr_priv(expr);
  31         struct nft_set_ext *ext;
  32         u64 timeout;
  33         void *elem;
  34
  35         if (!atomic_add_unless(&set->nelems, 1, set->size))
  36                 return NULL;
  37
  38         timeout = priv->timeout ? : set->timeout;
  39         elem = nft_set_elem_init(set, &priv->tmpl,
  40                                  &regs->data[priv->sreg_key], NULL,
  41                                  &regs->data[priv->sreg_data],
  42                                  timeout, 0, GFP_ATOMIC);
  43         if (elem == NULL)
  44                 goto err1;
  45
  46         ext = nft_set_elem_ext(set, elem);
  47         if (priv->expr != NULL &&
  48             nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0)
  49                 goto err2;
  50
  51         return elem;
  52
  53 err2:
  54         nft_set_elem_destroy(set, elem, false);
  55 err1:
  56         if (set->size)
  57                 atomic_dec(&set->nelems);
  58         return NULL;
  59 }
  60
  61 void nft_dynset_eval(const struct nft_expr *expr,
  62                      struct nft_regs *regs, const struct nft_pktinfo *pkt)
  63 {
  64         const struct nft_dynset *priv = nft_expr_priv(expr);
  65         struct nft_set *set = priv->set;
  66         const struct nft_set_ext *ext;
  67         u64 timeout;
  68
  69         if (priv->op == NFT_DYNSET_OP_DELETE) {
  70                 set->ops->delete(set, &regs->data[priv->sreg_key]);
  71                 return;
  72         }
  73
  74         if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
  75                              expr, regs, &ext)) {
  76                 if (priv->op == NFT_DYNSET_OP_UPDATE &&
  77                     nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
  78                         timeout = priv->timeout ? : set->timeout;
  79                         *nft_set_ext_expiration(ext) = get_jiffies_64() + timeout;
  80                 }
  81
  82                 nft_set_elem_update_expr(ext, regs, pkt);
  83
  84                 if (priv->invert)
  85                         regs->verdict.code = NFT_BREAK;
  86                 return;
  87         }
  88
  89         if (!priv->invert)
  90                 regs->verdict.code = NFT_BREAK;
  91 }
  92
  93 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
  94         [NFTA_DYNSET_SET_NAME]  = { .type = NLA_STRING,
  95                                     .len = NFT_SET_MAXNAMELEN - 1 },
  96         [NFTA_DYNSET_SET_ID]    = { .type = NLA_U32 },
  97         [NFTA_DYNSET_OP]        = { .type = NLA_U32 },
  98         [NFTA_DYNSET_SREG_KEY]  = { .type = NLA_U32 },
  99         [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
 100         [NFTA_DYNSET_TIMEOUT]   = { .type = NLA_U64 },
 101         [NFTA_DYNSET_EXPR]      = { .type = NLA_NESTED },
 102         [NFTA_DYNSET_FLAGS]     = { .type = NLA_U32 },
 103 };
 104
 105 static int nft_dynset_init(const struct nft_ctx *ctx,
 106                            const struct nft_expr *expr,
 107                            const struct nlattr * const tb[])
 108 {
 109         struct nft_dynset *priv = nft_expr_priv(expr);
 110         u8 genmask = nft_genmask_next(ctx->net);
 111         struct nft_set *set;
 112         u64 timeout;
 113         int err;
 114
 115         lockdep_assert_held(&ctx->net->nft.commit_mutex);
 116
 117         if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
 118             tb[NFTA_DYNSET_OP] == NULL ||
 119             tb[NFTA_DYNSET_SREG_KEY] == NULL)
 120                 return -EINVAL;
 121
 122         if (tb[NFTA_DYNSET_FLAGS]) {
 123                 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
 124
 125                 if (flags & ~NFT_DYNSET_F_INV)
 126                         return -EINVAL;
 127                 if (flags & NFT_DYNSET_F_INV)
 128                         priv->invert = true;
 129         }
 130
 131         set = nft_set_lookup_global(ctx->net, ctx->table,
 132                                     tb[NFTA_DYNSET_SET_NAME],
 133                                     tb[NFTA_DYNSET_SET_ID], genmask);
 134         if (IS_ERR(set))
 135                 return PTR_ERR(set);
 136
 137         if (set->ops->update == NULL)
 138                 return -EOPNOTSUPP;
 139
 140         if (set->flags & NFT_SET_CONSTANT)
 141                 return -EBUSY;
 142
 143         priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
 144         switch (priv->op) {
 145         case NFT_DYNSET_OP_ADD:
 146         case NFT_DYNSET_OP_DELETE:
 147                 break;
 148         case NFT_DYNSET_OP_UPDATE:
 149                 if (!(set->flags & NFT_SET_TIMEOUT))
 150                         return -EOPNOTSUPP;
 151                 break;
 152         default:
 153                 return -EOPNOTSUPP;
 154         }
 155
 156         timeout = 0;
 157         if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
 158                 if (!(set->flags & NFT_SET_TIMEOUT))
 159                         return -EINVAL;
 160                 timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64(
 161                                                 tb[NFTA_DYNSET_TIMEOUT])));
 162         }
 163
 164         priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
 165         err = nft_validate_register_load(priv->sreg_key, set->klen);
 166         if (err < 0)
 167                 return err;
 168
 169         if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
 170                 if (!(set->flags & NFT_SET_MAP))
 171                         return -EINVAL;
 172                 if (set->dtype == NFT_DATA_VERDICT)
 173                         return -EOPNOTSUPP;
 174
 175                 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
 176                 err = nft_validate_register_load(priv->sreg_data, set->dlen);
 177                 if (err < 0)
 178                         return err;
 179         } else if (set->flags & NFT_SET_MAP)
 180                 return -EINVAL;
 181
 182         if (tb[NFTA_DYNSET_EXPR] != NULL) {
 183                 if (!(set->flags & NFT_SET_EVAL))
 184                         return -EINVAL;
 185
 186                 priv->expr = nft_set_elem_expr_alloc(ctx, set,
 187                                                      tb[NFTA_DYNSET_EXPR]);
 188                 if (IS_ERR(priv->expr))
 189                         return PTR_ERR(priv->expr);
 190
 191                 if (set->expr && set->expr->ops != priv->expr->ops) {
 192                         err = -EOPNOTSUPP;
 193                         goto err_expr_free;
 194                 }
 195         }
 196
 197         nft_set_ext_prepare(&priv->tmpl);
 198         nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
 199         if (set->flags & NFT_SET_MAP)
 200                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
 201         if (priv->expr != NULL)
 202                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR,
 203                                        priv->expr->ops->size);
 204         if (set->flags & NFT_SET_TIMEOUT) {
 205                 if (timeout || set->timeout)
 206                         nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
 207         }
 208
 209         priv->timeout = timeout;
 210
 211         err = nf_tables_bind_set(ctx, set, &priv->binding);
 212         if (err < 0)
 213                 goto err_expr_free;
 214
 215         if (set->size == 0)
 216                 set->size = 0xffff;
 217
 218         priv->set = set;
 219         return 0;
 220
 221 err_expr_free:
 222         if (priv->expr != NULL)
 223                 nft_expr_destroy(ctx, priv->expr);
 224         return err;
 225 }
 226
 227 static void nft_dynset_deactivate(const struct nft_ctx *ctx,
 228                                   const struct nft_expr *expr,
 229                                   enum nft_trans_phase phase)
 230 {
 231         struct nft_dynset *priv = nft_expr_priv(expr);
 232
 233         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 234 }
 235
 236 static void nft_dynset_activate(const struct nft_ctx *ctx,
 237                                 const struct nft_expr *expr)
 238 {
 239         struct nft_dynset *priv = nft_expr_priv(expr);
 240
 241         priv->set->use++;
 242 }
 243
 244 static void nft_dynset_destroy(const struct nft_ctx *ctx,
 245                                const struct nft_expr *expr)
 246 {
 247         struct nft_dynset *priv = nft_expr_priv(expr);
 248
 249         if (priv->expr != NULL)
 250                 nft_expr_destroy(ctx, priv->expr);
 251
 252         nf_tables_destroy_set(ctx, priv->set);
 253 }
 254
 255 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
 256 {
 257         const struct nft_dynset *priv = nft_expr_priv(expr);
 258         u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
 259
 260         if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
 261                 goto nla_put_failure;
 262         if (priv->set->flags & NFT_SET_MAP &&
 263             nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
 264                 goto nla_put_failure;
 265         if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
 266                 goto nla_put_failure;
 267         if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
 268                 goto nla_put_failure;
 269         if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
 270                          cpu_to_be64(jiffies_to_msecs(priv->timeout)),
 271                          NFTA_DYNSET_PAD))
 272                 goto nla_put_failure;
 273         if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr))
 274                 goto nla_put_failure;
 275         if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
 276                 goto nla_put_failure;
 277         return 0;
 278
 279 nla_put_failure:
 280         return -1;
 281 }
 282
 283 static const struct nft_expr_ops nft_dynset_ops = {
 284         .type           = &nft_dynset_type,
 285         .size           = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
 286         .eval           = nft_dynset_eval,
 287         .init           = nft_dynset_init,
 288         .destroy        = nft_dynset_destroy,
 289         .activate       = nft_dynset_activate,
 290         .deactivate     = nft_dynset_deactivate,
 291         .dump           = nft_dynset_dump,
 292 };
 293
 294 struct nft_expr_type nft_dynset_type __read_mostly = {
 295         .name           = "dynset",
 296         .ops            = &nft_dynset_ops,
 297         .policy         = nft_dynset_policy,
 298         .maxattr        = NFTA_DYNSET_MAX,
 299         .owner          = THIS_MODULE,
 300 };