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 int nft_expr_clone(struct nft_expr *dst, struct nft_expr *src)
  28 {
  29         int err;
  30
  31         if (src->ops->clone) {
  32                 dst->ops = src->ops;
  33                 err = src->ops->clone(dst, src);
  34                 if (err < 0)
  35                         return err;
  36         } else {
  37                 memcpy(dst, src, src->ops->size);
  38         }
  39
  40         __module_get(src->ops->type->owner);
  41         return 0;
  42 }
  43
  44 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
  45                             struct nft_regs *regs)
  46 {
  47         const struct nft_dynset *priv = nft_expr_priv(expr);
  48         struct nft_set_ext *ext;
  49         u64 timeout;
  50         void *elem;
  51
  52         if (!atomic_add_unless(&set->nelems, 1, set->size))
  53                 return NULL;
  54
  55         timeout = priv->timeout ? : set->timeout;
  56         elem = nft_set_elem_init(set, &priv->tmpl,
  57                                  &regs->data[priv->sreg_key],
  58                                  &regs->data[priv->sreg_data],
  59                                  timeout, 0, GFP_ATOMIC);
  60         if (elem == NULL)
  61                 goto err1;
  62
  63         ext = nft_set_elem_ext(set, elem);
  64         if (priv->expr != NULL &&
  65             nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0)
  66                 goto err2;
  67
  68         return elem;
  69
  70 err2:
  71         nft_set_elem_destroy(set, elem, false);
  72 err1:
  73         if (set->size)
  74                 atomic_dec(&set->nelems);
  75         return NULL;
  76 }
  77
  78 void nft_dynset_eval(const struct nft_expr *expr,
  79                      struct nft_regs *regs, const struct nft_pktinfo *pkt)
  80 {
  81         const struct nft_dynset *priv = nft_expr_priv(expr);
  82         struct nft_set *set = priv->set;
  83         const struct nft_set_ext *ext;
  84         const struct nft_expr *sexpr;
  85         u64 timeout;
  86
  87         if (priv->op == NFT_DYNSET_OP_DELETE) {
  88                 set->ops->delete(set, &regs->data[priv->sreg_key]);
  89                 return;
  90         }
  91
  92         if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
  93                              expr, regs, &ext)) {
  94                 sexpr = NULL;
  95                 if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR))
  96                         sexpr = nft_set_ext_expr(ext);
  97
  98                 if (priv->op == NFT_DYNSET_OP_UPDATE &&
  99                     nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
 100                         timeout = priv->timeout ? : set->timeout;
 101                         *nft_set_ext_expiration(ext) = get_jiffies_64() + timeout;
 102                 }
 103
 104                 if (sexpr != NULL)
 105                         sexpr->ops->eval(sexpr, regs, pkt);
 106
 107                 if (priv->invert)
 108                         regs->verdict.code = NFT_BREAK;
 109                 return;
 110         }
 111
 112         if (!priv->invert)
 113                 regs->verdict.code = NFT_BREAK;
 114 }
 115
 116 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
 117         [NFTA_DYNSET_SET_NAME]  = { .type = NLA_STRING,
 118                                     .len = NFT_SET_MAXNAMELEN - 1 },
 119         [NFTA_DYNSET_SET_ID]    = { .type = NLA_U32 },
 120         [NFTA_DYNSET_OP]        = { .type = NLA_U32 },
 121         [NFTA_DYNSET_SREG_KEY]  = { .type = NLA_U32 },
 122         [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
 123         [NFTA_DYNSET_TIMEOUT]   = { .type = NLA_U64 },
 124         [NFTA_DYNSET_EXPR]      = { .type = NLA_NESTED },
 125         [NFTA_DYNSET_FLAGS]     = { .type = NLA_U32 },
 126 };
 127
 128 static int nft_dynset_init(const struct nft_ctx *ctx,
 129                            const struct nft_expr *expr,
 130                            const struct nlattr * const tb[])
 131 {
 132         struct nft_dynset *priv = nft_expr_priv(expr);
 133         u8 genmask = nft_genmask_next(ctx->net);
 134         struct nft_set *set;
 135         u64 timeout;
 136         int err;
 137
 138         lockdep_assert_held(&ctx->net->nft.commit_mutex);
 139
 140         if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
 141             tb[NFTA_DYNSET_OP] == NULL ||
 142             tb[NFTA_DYNSET_SREG_KEY] == NULL)
 143                 return -EINVAL;
 144
 145         if (tb[NFTA_DYNSET_FLAGS]) {
 146                 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
 147
 148                 if (flags & ~NFT_DYNSET_F_INV)
 149                         return -EINVAL;
 150                 if (flags & NFT_DYNSET_F_INV)
 151                         priv->invert = true;
 152         }
 153
 154         set = nft_set_lookup_global(ctx->net, ctx->table,
 155                                     tb[NFTA_DYNSET_SET_NAME],
 156                                     tb[NFTA_DYNSET_SET_ID], genmask);
 157         if (IS_ERR(set))
 158                 return PTR_ERR(set);
 159
 160         if (set->ops->update == NULL)
 161                 return -EOPNOTSUPP;
 162
 163         if (set->flags & NFT_SET_CONSTANT)
 164                 return -EBUSY;
 165
 166         priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
 167         switch (priv->op) {
 168         case NFT_DYNSET_OP_ADD:
 169         case NFT_DYNSET_OP_DELETE:
 170                 break;
 171         case NFT_DYNSET_OP_UPDATE:
 172                 if (!(set->flags & NFT_SET_TIMEOUT))
 173                         return -EOPNOTSUPP;
 174                 break;
 175         default:
 176                 return -EOPNOTSUPP;
 177         }
 178
 179         timeout = 0;
 180         if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
 181                 if (!(set->flags & NFT_SET_TIMEOUT))
 182                         return -EINVAL;
 183                 timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64(
 184                                                 tb[NFTA_DYNSET_TIMEOUT])));
 185         }
 186
 187         priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
 188         err = nft_validate_register_load(priv->sreg_key, set->klen);
 189         if (err < 0)
 190                 return err;
 191
 192         if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
 193                 if (!(set->flags & NFT_SET_MAP))
 194                         return -EINVAL;
 195                 if (set->dtype == NFT_DATA_VERDICT)
 196                         return -EOPNOTSUPP;
 197
 198                 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
 199                 err = nft_validate_register_load(priv->sreg_data, set->dlen);
 200                 if (err < 0)
 201                         return err;
 202         } else if (set->flags & NFT_SET_MAP)
 203                 return -EINVAL;
 204
 205         if (tb[NFTA_DYNSET_EXPR] != NULL) {
 206                 if (!(set->flags & NFT_SET_EVAL))
 207                         return -EINVAL;
 208
 209                 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]);
 210                 if (IS_ERR(priv->expr))
 211                         return PTR_ERR(priv->expr);
 212
 213                 err = -EOPNOTSUPP;
 214                 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL))
 215                         goto err1;
 216
 217                 if (priv->expr->ops->type->flags & NFT_EXPR_GC) {
 218                         if (set->flags & NFT_SET_TIMEOUT)
 219                                 goto err1;
 220                         if (!set->ops->gc_init)
 221                                 goto err1;
 222                         set->ops->gc_init(set);
 223                 }
 224         }
 225
 226         nft_set_ext_prepare(&priv->tmpl);
 227         nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
 228         if (set->flags & NFT_SET_MAP)
 229                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
 230         if (priv->expr != NULL)
 231                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR,
 232                                        priv->expr->ops->size);
 233         if (set->flags & NFT_SET_TIMEOUT) {
 234                 if (timeout || set->timeout)
 235                         nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
 236         }
 237
 238         priv->timeout = timeout;
 239
 240         err = nf_tables_bind_set(ctx, set, &priv->binding);
 241         if (err < 0)
 242                 goto err1;
 243
 244         if (set->size == 0)
 245                 set->size = 0xffff;
 246
 247         priv->set = set;
 248         return 0;
 249
 250 err1:
 251         if (priv->expr != NULL)
 252                 nft_expr_destroy(ctx, priv->expr);
 253         return err;
 254 }
 255
 256 static void nft_dynset_deactivate(const struct nft_ctx *ctx,
 257                                   const struct nft_expr *expr,
 258                                   enum nft_trans_phase phase)
 259 {
 260         struct nft_dynset *priv = nft_expr_priv(expr);
 261
 262         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 263 }
 264
 265 static void nft_dynset_activate(const struct nft_ctx *ctx,
 266                                 const struct nft_expr *expr)
 267 {
 268         struct nft_dynset *priv = nft_expr_priv(expr);
 269
 270         priv->set->use++;
 271 }
 272
 273 static void nft_dynset_destroy(const struct nft_ctx *ctx,
 274                                const struct nft_expr *expr)
 275 {
 276         struct nft_dynset *priv = nft_expr_priv(expr);
 277
 278         if (priv->expr != NULL)
 279                 nft_expr_destroy(ctx, priv->expr);
 280
 281         nf_tables_destroy_set(ctx, priv->set);
 282 }
 283
 284 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
 285 {
 286         const struct nft_dynset *priv = nft_expr_priv(expr);
 287         u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
 288
 289         if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
 290                 goto nla_put_failure;
 291         if (priv->set->flags & NFT_SET_MAP &&
 292             nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
 293                 goto nla_put_failure;
 294         if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
 295                 goto nla_put_failure;
 296         if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
 297                 goto nla_put_failure;
 298         if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
 299                          cpu_to_be64(jiffies_to_msecs(priv->timeout)),
 300                          NFTA_DYNSET_PAD))
 301                 goto nla_put_failure;
 302         if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr))
 303                 goto nla_put_failure;
 304         if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
 305                 goto nla_put_failure;
 306         return 0;
 307
 308 nla_put_failure:
 309         return -1;
 310 }
 311
 312 static const struct nft_expr_ops nft_dynset_ops = {
 313         .type           = &nft_dynset_type,
 314         .size           = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
 315         .eval           = nft_dynset_eval,
 316         .init           = nft_dynset_init,
 317         .destroy        = nft_dynset_destroy,
 318         .activate       = nft_dynset_activate,
 319         .deactivate     = nft_dynset_deactivate,
 320         .dump           = nft_dynset_dump,
 321 };
 322
 323 struct nft_expr_type nft_dynset_type __read_mostly = {
 324         .name           = "dynset",
 325         .ops            = &nft_dynset_ops,
 326         .policy         = nft_dynset_policy,
 327         .maxattr        = NFTA_DYNSET_MAX,
 328         .owner          = THIS_MODULE,
 329 };