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         bool                            expr;
  23         u8                              num_exprs;
  24         u64                             timeout;
  25         struct nft_expr                 *expr_array[NFT_SET_EXPR_MAX];
  26         struct nft_set_binding          binding;
  27 };
  28
  29 static int nft_dynset_expr_setup(const struct nft_dynset *priv,
  30                                  const struct nft_set_ext *ext)
  31 {
  32         struct nft_set_elem_expr *elem_expr = nft_set_ext_expr(ext);
  33         struct nft_expr *expr;
  34         int i;
  35
  36         for (i = 0; i < priv->num_exprs; i++) {
  37                 expr = nft_setelem_expr_at(elem_expr, elem_expr->size);
  38                 if (nft_expr_clone(expr, priv->expr_array[i]) < 0)
  39                         return -1;
  40
  41                 elem_expr->size += priv->expr_array[i]->ops->size;
  42         }
  43
  44         return 0;
  45 }
  46
  47 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
  48                             struct nft_regs *regs)
  49 {
  50         const struct nft_dynset *priv = nft_expr_priv(expr);
  51         struct nft_set_ext *ext;
  52         u64 timeout;
  53         void *elem;
  54
  55         if (!atomic_add_unless(&set->nelems, 1, set->size))
  56                 return NULL;
  57
  58         timeout = priv->timeout ? : set->timeout;
  59         elem = nft_set_elem_init(set, &priv->tmpl,
  60                                  &regs->data[priv->sreg_key], NULL,
  61                                  &regs->data[priv->sreg_data],
  62                                  timeout, 0, GFP_ATOMIC);
  63         if (elem == NULL)
  64                 goto err1;
  65
  66         ext = nft_set_elem_ext(set, elem);
  67         if (priv->num_exprs && nft_dynset_expr_setup(priv, ext) < 0)
  68                 goto err2;
  69
  70         return elem;
  71
  72 err2:
  73         nft_set_elem_destroy(set, elem, false);
  74 err1:
  75         if (set->size)
  76                 atomic_dec(&set->nelems);
  77         return NULL;
  78 }
  79
  80 void nft_dynset_eval(const struct nft_expr *expr,
  81                      struct nft_regs *regs, const struct nft_pktinfo *pkt)
  82 {
  83         const struct nft_dynset *priv = nft_expr_priv(expr);
  84         struct nft_set *set = priv->set;
  85         const struct nft_set_ext *ext;
  86         u64 timeout;
  87
  88         if (priv->op == NFT_DYNSET_OP_DELETE) {
  89                 set->ops->delete(set, &regs->data[priv->sreg_key]);
  90                 return;
  91         }
  92
  93         if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
  94                              expr, regs, &ext)) {
  95                 if (priv->op == NFT_DYNSET_OP_UPDATE &&
  96                     nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
  97                         timeout = priv->timeout ? : set->timeout;
  98                         *nft_set_ext_expiration(ext) = get_jiffies_64() + timeout;
  99                 }
 100
 101                 nft_set_elem_update_expr(ext, regs, pkt);
 102
 103                 if (priv->invert)
 104                         regs->verdict.code = NFT_BREAK;
 105                 return;
 106         }
 107
 108         if (!priv->invert)
 109                 regs->verdict.code = NFT_BREAK;
 110 }
 111
 112 static void nft_dynset_ext_add_expr(struct nft_dynset *priv)
 113 {
 114         u8 size = 0;
 115         int i;
 116
 117         for (i = 0; i < priv->num_exprs; i++)
 118                 size += priv->expr_array[i]->ops->size;
 119
 120         nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPRESSIONS,
 121                                sizeof(struct nft_set_elem_expr) + size);
 122 }
 123
 124 static struct nft_expr *
 125 nft_dynset_expr_alloc(const struct nft_ctx *ctx, const struct nft_set *set,
 126                       const struct nlattr *attr, int pos)
 127 {
 128         struct nft_expr *expr;
 129         int err;
 130
 131         expr = nft_set_elem_expr_alloc(ctx, set, attr);
 132         if (IS_ERR(expr))
 133                 return expr;
 134
 135         if (set->exprs[pos] && set->exprs[pos]->ops != expr->ops) {
 136                 err = -EOPNOTSUPP;
 137                 goto err_dynset_expr;
 138         }
 139
 140         return expr;
 141
 142 err_dynset_expr:
 143         nft_expr_destroy(ctx, expr);
 144         return ERR_PTR(err);
 145 }
 146
 147 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
 148         [NFTA_DYNSET_SET_NAME]  = { .type = NLA_STRING,
 149                                     .len = NFT_SET_MAXNAMELEN - 1 },
 150         [NFTA_DYNSET_SET_ID]    = { .type = NLA_U32 },
 151         [NFTA_DYNSET_OP]        = { .type = NLA_U32 },
 152         [NFTA_DYNSET_SREG_KEY]  = { .type = NLA_U32 },
 153         [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
 154         [NFTA_DYNSET_TIMEOUT]   = { .type = NLA_U64 },
 155         [NFTA_DYNSET_EXPR]      = { .type = NLA_NESTED },
 156         [NFTA_DYNSET_FLAGS]     = { .type = NLA_U32 },
 157         [NFTA_DYNSET_EXPRESSIONS] = { .type = NLA_NESTED },
 158 };
 159
 160 static int nft_dynset_init(const struct nft_ctx *ctx,
 161                            const struct nft_expr *expr,
 162                            const struct nlattr * const tb[])
 163 {
 164         struct nft_dynset *priv = nft_expr_priv(expr);
 165         u8 genmask = nft_genmask_next(ctx->net);
 166         struct nft_set *set;
 167         u64 timeout;
 168         int err, i;
 169
 170         lockdep_assert_held(&ctx->net->nft.commit_mutex);
 171
 172         if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
 173             tb[NFTA_DYNSET_OP] == NULL ||
 174             tb[NFTA_DYNSET_SREG_KEY] == NULL)
 175                 return -EINVAL;
 176
 177         if (tb[NFTA_DYNSET_FLAGS]) {
 178                 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
 179                 if (flags & ~(NFT_DYNSET_F_INV | NFT_DYNSET_F_EXPR))
 180                         return -EOPNOTSUPP;
 181                 if (flags & NFT_DYNSET_F_INV)
 182                         priv->invert = true;
 183                 if (flags & NFT_DYNSET_F_EXPR)
 184                         priv->expr = true;
 185         }
 186
 187         set = nft_set_lookup_global(ctx->net, ctx->table,
 188                                     tb[NFTA_DYNSET_SET_NAME],
 189                                     tb[NFTA_DYNSET_SET_ID], genmask);
 190         if (IS_ERR(set))
 191                 return PTR_ERR(set);
 192
 193         if (set->ops->update == NULL)
 194                 return -EOPNOTSUPP;
 195
 196         if (set->flags & NFT_SET_CONSTANT)
 197                 return -EBUSY;
 198
 199         priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
 200         switch (priv->op) {
 201         case NFT_DYNSET_OP_ADD:
 202         case NFT_DYNSET_OP_DELETE:
 203                 break;
 204         case NFT_DYNSET_OP_UPDATE:
 205                 if (!(set->flags & NFT_SET_TIMEOUT))
 206                         return -EOPNOTSUPP;
 207                 break;
 208         default:
 209                 return -EOPNOTSUPP;
 210         }
 211
 212         timeout = 0;
 213         if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
 214                 if (!(set->flags & NFT_SET_TIMEOUT))
 215                         return -EOPNOTSUPP;
 216
 217                 err = nf_msecs_to_jiffies64(tb[NFTA_DYNSET_TIMEOUT], &timeout);
 218                 if (err)
 219                         return err;
 220         }
 221
 222         priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
 223         err = nft_validate_register_load(priv->sreg_key, set->klen);
 224         if (err < 0)
 225                 return err;
 226
 227         if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
 228                 if (!(set->flags & NFT_SET_MAP))
 229                         return -EOPNOTSUPP;
 230                 if (set->dtype == NFT_DATA_VERDICT)
 231                         return -EOPNOTSUPP;
 232
 233                 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
 234                 err = nft_validate_register_load(priv->sreg_data, set->dlen);
 235                 if (err < 0)
 236                         return err;
 237         } else if (set->flags & NFT_SET_MAP)
 238                 return -EINVAL;
 239
 240         if ((tb[NFTA_DYNSET_EXPR] || tb[NFTA_DYNSET_EXPRESSIONS]) &&
 241             !(set->flags & NFT_SET_EVAL))
 242                 return -EINVAL;
 243
 244         if (tb[NFTA_DYNSET_EXPR]) {
 245                 struct nft_expr *dynset_expr;
 246
 247                 dynset_expr = nft_dynset_expr_alloc(ctx, set,
 248                                                     tb[NFTA_DYNSET_EXPR], 0);
 249                 if (IS_ERR(dynset_expr))
 250                         return PTR_ERR(dynset_expr);
 251
 252                 priv->num_exprs++;
 253                 priv->expr_array[0] = dynset_expr;
 254
 255                 if (set->num_exprs > 1 ||
 256                     (set->num_exprs == 1 &&
 257                      dynset_expr->ops != set->exprs[0]->ops)) {
 258                         err = -EOPNOTSUPP;
 259                         goto err_expr_free;
 260                 }
 261         } else if (tb[NFTA_DYNSET_EXPRESSIONS]) {
 262                 struct nft_expr *dynset_expr;
 263                 struct nlattr *tmp;
 264                 int left;
 265
 266                 if (!priv->expr)
 267                         return -EINVAL;
 268
 269                 i = 0;
 270                 nla_for_each_nested(tmp, tb[NFTA_DYNSET_EXPRESSIONS], left) {
 271                         if (i == NFT_SET_EXPR_MAX) {
 272                                 err = -E2BIG;
 273                                 goto err_expr_free;
 274                         }
 275                         if (nla_type(tmp) != NFTA_LIST_ELEM) {
 276                                 err = -EINVAL;
 277                                 goto err_expr_free;
 278                         }
 279                         dynset_expr = nft_dynset_expr_alloc(ctx, set, tmp, i);
 280                         if (IS_ERR(dynset_expr)) {
 281                                 err = PTR_ERR(dynset_expr);
 282                                 goto err_expr_free;
 283                         }
 284                         priv->expr_array[i] = dynset_expr;
 285                         priv->num_exprs++;
 286
 287                         if (set->num_exprs &&
 288                             dynset_expr->ops != set->exprs[i]->ops) {
 289                                 err = -EOPNOTSUPP;
 290                                 goto err_expr_free;
 291                         }
 292                         i++;
 293                 }
 294                 if (set->num_exprs && set->num_exprs != i) {
 295                         err = -EOPNOTSUPP;
 296                         goto err_expr_free;
 297                 }
 298         }
 299
 300         nft_set_ext_prepare(&priv->tmpl);
 301         nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
 302         if (set->flags & NFT_SET_MAP)
 303                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
 304
 305         if (priv->num_exprs)
 306                 nft_dynset_ext_add_expr(priv);
 307
 308         if (set->flags & NFT_SET_TIMEOUT) {
 309                 if (timeout || set->timeout)
 310                         nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
 311         }
 312
 313         priv->timeout = timeout;
 314
 315         err = nf_tables_bind_set(ctx, set, &priv->binding);
 316         if (err < 0)
 317                 goto err_expr_free;
 318
 319         if (set->size == 0)
 320                 set->size = 0xffff;
 321
 322         priv->set = set;
 323         return 0;
 324
 325 err_expr_free:
 326         for (i = 0; i < priv->num_exprs; i++)
 327                 nft_expr_destroy(ctx, priv->expr_array[i]);
 328         return err;
 329 }
 330
 331 static void nft_dynset_deactivate(const struct nft_ctx *ctx,
 332                                   const struct nft_expr *expr,
 333                                   enum nft_trans_phase phase)
 334 {
 335         struct nft_dynset *priv = nft_expr_priv(expr);
 336
 337         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 338 }
 339
 340 static void nft_dynset_activate(const struct nft_ctx *ctx,
 341                                 const struct nft_expr *expr)
 342 {
 343         struct nft_dynset *priv = nft_expr_priv(expr);
 344
 345         priv->set->use++;
 346 }
 347
 348 static void nft_dynset_destroy(const struct nft_ctx *ctx,
 349                                const struct nft_expr *expr)
 350 {
 351         struct nft_dynset *priv = nft_expr_priv(expr);
 352         int i;
 353
 354         for (i = 0; i < priv->num_exprs; i++)
 355                 nft_expr_destroy(ctx, priv->expr_array[i]);
 356
 357         nf_tables_destroy_set(ctx, priv->set);
 358 }
 359
 360 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
 361 {
 362         const struct nft_dynset *priv = nft_expr_priv(expr);
 363         u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
 364         int i;
 365
 366         if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
 367                 goto nla_put_failure;
 368         if (priv->set->flags & NFT_SET_MAP &&
 369             nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
 370                 goto nla_put_failure;
 371         if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
 372                 goto nla_put_failure;
 373         if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
 374                 goto nla_put_failure;
 375         if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
 376                          nf_jiffies64_to_msecs(priv->timeout),
 377                          NFTA_DYNSET_PAD))
 378                 goto nla_put_failure;
 379         if (priv->num_exprs == 1) {
 380                 if (nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr_array[0]))
 381                         goto nla_put_failure;
 382         } else if (priv->num_exprs > 1) {
 383                 struct nlattr *nest;
 384
 385                 nest = nla_nest_start_noflag(skb, NFTA_DYNSET_EXPRESSIONS);
 386                 if (!nest)
 387                         goto nla_put_failure;
 388
 389                 for (i = 0; i < priv->num_exprs; i++) {
 390                         if (nft_expr_dump(skb, NFTA_LIST_ELEM,
 391                                           priv->expr_array[i]))
 392                                 goto nla_put_failure;
 393                 }
 394                 nla_nest_end(skb, nest);
 395         }
 396         if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
 397                 goto nla_put_failure;
 398         return 0;
 399
 400 nla_put_failure:
 401         return -1;
 402 }
 403
 404 static const struct nft_expr_ops nft_dynset_ops = {
 405         .type           = &nft_dynset_type,
 406         .size           = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
 407         .eval           = nft_dynset_eval,
 408         .init           = nft_dynset_init,
 409         .destroy        = nft_dynset_destroy,
 410         .activate       = nft_dynset_activate,
 411         .deactivate     = nft_dynset_deactivate,
 412         .dump           = nft_dynset_dump,
 413 };
 414
 415 struct nft_expr_type nft_dynset_type __read_mostly = {
 416         .name           = "dynset",
 417         .ops            = &nft_dynset_ops,
 418         .policy         = nft_dynset_policy,
 419         .maxattr        = NFTA_DYNSET_MAX,
 420         .owner          = THIS_MODULE,
 421 };