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         u8                              sreg_key;
  20         u8                              sreg_data;
  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], GFP_ATOMIC) < 0)
  39                         return -1;
  40
  41                 elem_expr->size += priv->expr_array[i]->ops->size;
  42         }
  43
  44         return 0;
  45 }
  46
  47 static struct nft_elem_priv *nft_dynset_new(struct nft_set *set,
  48                                             const struct nft_expr *expr,
  49                                             struct nft_regs *regs)
  50 {
  51         const struct nft_dynset *priv = nft_expr_priv(expr);
  52         struct nft_set_ext *ext;
  53         void *elem_priv;
  54         u64 timeout;
  55
  56         if (!atomic_add_unless(&set->nelems, 1, set->size))
  57                 return NULL;
  58
  59         timeout = priv->timeout ? : READ_ONCE(set->timeout);
  60         elem_priv = nft_set_elem_init(set, &priv->tmpl,
  61                                       &regs->data[priv->sreg_key], NULL,
  62                                       &regs->data[priv->sreg_data],
  63                                       timeout, 0, GFP_ATOMIC);
  64         if (IS_ERR(elem_priv))
  65                 goto err1;
  66
  67         ext = nft_set_elem_ext(set, elem_priv);
  68         if (priv->num_exprs && nft_dynset_expr_setup(priv, ext) < 0)
  69                 goto err2;
  70
  71         return elem_priv;
  72
  73 err2:
  74         nft_set_elem_destroy(set, elem_priv, false);
  75 err1:
  76         if (set->size)
  77                 atomic_dec(&set->nelems);
  78         return NULL;
  79 }
  80
  81 void nft_dynset_eval(const struct nft_expr *expr,
  82                      struct nft_regs *regs, const struct nft_pktinfo *pkt)
  83 {
  84         const struct nft_dynset *priv = nft_expr_priv(expr);
  85         struct nft_set *set = priv->set;
  86         const struct nft_set_ext *ext;
  87         u64 timeout;
  88
  89         if (priv->op == NFT_DYNSET_OP_DELETE) {
  90                 set->ops->delete(set, &regs->data[priv->sreg_key]);
  91                 return;
  92         }
  93
  94         if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
  95                              expr, regs, &ext)) {
  96                 if (priv->op == NFT_DYNSET_OP_UPDATE &&
  97                     nft_set_ext_exists(ext, NFT_SET_EXT_TIMEOUT) &&
  98                     READ_ONCE(nft_set_ext_timeout(ext)->timeout) != 0) {
  99                         timeout = priv->timeout ? : READ_ONCE(set->timeout);
 100                         WRITE_ONCE(nft_set_ext_timeout(ext)->expiration, get_jiffies_64() + timeout);
 101                 }
 102
 103                 nft_set_elem_update_expr(ext, regs, pkt);
 104
 105                 if (priv->invert)
 106                         regs->verdict.code = NFT_BREAK;
 107                 return;
 108         }
 109
 110         if (!priv->invert)
 111                 regs->verdict.code = NFT_BREAK;
 112 }
 113
 114 static void nft_dynset_ext_add_expr(struct nft_dynset *priv)
 115 {
 116         u8 size = 0;
 117         int i;
 118
 119         for (i = 0; i < priv->num_exprs; i++)
 120                 size += priv->expr_array[i]->ops->size;
 121
 122         nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPRESSIONS,
 123                                sizeof(struct nft_set_elem_expr) + size);
 124 }
 125
 126 static struct nft_expr *
 127 nft_dynset_expr_alloc(const struct nft_ctx *ctx, const struct nft_set *set,
 128                       const struct nlattr *attr, int pos)
 129 {
 130         struct nft_expr *expr;
 131         int err;
 132
 133         expr = nft_set_elem_expr_alloc(ctx, set, attr);
 134         if (IS_ERR(expr))
 135                 return expr;
 136
 137         if (set->exprs[pos] && set->exprs[pos]->ops != expr->ops) {
 138                 err = -EOPNOTSUPP;
 139                 goto err_dynset_expr;
 140         }
 141
 142         return expr;
 143
 144 err_dynset_expr:
 145         nft_expr_destroy(ctx, expr);
 146         return ERR_PTR(err);
 147 }
 148
 149 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
 150         [NFTA_DYNSET_SET_NAME]  = { .type = NLA_STRING,
 151                                     .len = NFT_SET_MAXNAMELEN - 1 },
 152         [NFTA_DYNSET_SET_ID]    = { .type = NLA_U32 },
 153         [NFTA_DYNSET_OP]        = NLA_POLICY_MAX(NLA_BE32, 255),
 154         [NFTA_DYNSET_SREG_KEY]  = { .type = NLA_U32 },
 155         [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 },
 156         [NFTA_DYNSET_TIMEOUT]   = { .type = NLA_U64 },
 157         [NFTA_DYNSET_EXPR]      = { .type = NLA_NESTED },
 158         [NFTA_DYNSET_FLAGS]     = { .type = NLA_U32 },
 159         [NFTA_DYNSET_EXPRESSIONS] = { .type = NLA_NESTED },
 160 };
 161
 162 static int nft_dynset_init(const struct nft_ctx *ctx,
 163                            const struct nft_expr *expr,
 164                            const struct nlattr * const tb[])
 165 {
 166         struct nftables_pernet *nft_net = nft_pernet(ctx->net);
 167         struct nft_dynset *priv = nft_expr_priv(expr);
 168         u8 genmask = nft_genmask_next(ctx->net);
 169         struct nft_set *set;
 170         u64 timeout;
 171         int err, i;
 172
 173         lockdep_assert_held(&nft_net->commit_mutex);
 174
 175         if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
 176             tb[NFTA_DYNSET_OP] == NULL ||
 177             tb[NFTA_DYNSET_SREG_KEY] == NULL)
 178                 return -EINVAL;
 179
 180         if (tb[NFTA_DYNSET_FLAGS]) {
 181                 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
 182                 if (flags & ~(NFT_DYNSET_F_INV | NFT_DYNSET_F_EXPR))
 183                         return -EOPNOTSUPP;
 184                 if (flags & NFT_DYNSET_F_INV)
 185                         priv->invert = true;
 186                 if (flags & NFT_DYNSET_F_EXPR)
 187                         priv->expr = true;
 188         }
 189
 190         set = nft_set_lookup_global(ctx->net, ctx->table,
 191                                     tb[NFTA_DYNSET_SET_NAME],
 192                                     tb[NFTA_DYNSET_SET_ID], genmask);
 193         if (IS_ERR(set))
 194                 return PTR_ERR(set);
 195
 196         if (set->flags & NFT_SET_OBJECT)
 197                 return -EOPNOTSUPP;
 198
 199         if (set->ops->update == NULL)
 200                 return -EOPNOTSUPP;
 201
 202         if (set->flags & NFT_SET_CONSTANT)
 203                 return -EBUSY;
 204
 205         priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
 206         if (priv->op > NFT_DYNSET_OP_DELETE)
 207                 return -EOPNOTSUPP;
 208
 209         timeout = 0;
 210         if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
 211                 if (!(set->flags & NFT_SET_TIMEOUT))
 212                         return -EOPNOTSUPP;
 213
 214                 err = nf_msecs_to_jiffies64(tb[NFTA_DYNSET_TIMEOUT], &timeout);
 215                 if (err)
 216                         return err;
 217         }
 218
 219         err = nft_parse_register_load(ctx, tb[NFTA_DYNSET_SREG_KEY], &priv->sreg_key,
 220                                       set->klen);
 221         if (err < 0)
 222                 return err;
 223
 224         if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
 225                 if (!(set->flags & NFT_SET_MAP))
 226                         return -EOPNOTSUPP;
 227                 if (set->dtype == NFT_DATA_VERDICT)
 228                         return -EOPNOTSUPP;
 229
 230                 err = nft_parse_register_load(ctx, tb[NFTA_DYNSET_SREG_DATA],
 231                                               &priv->sreg_data, set->dlen);
 232                 if (err < 0)
 233                         return err;
 234         } else if (set->flags & NFT_SET_MAP)
 235                 return -EINVAL;
 236
 237         if ((tb[NFTA_DYNSET_EXPR] || tb[NFTA_DYNSET_EXPRESSIONS]) &&
 238             !(set->flags & NFT_SET_EVAL))
 239                 return -EINVAL;
 240
 241         if (tb[NFTA_DYNSET_EXPR]) {
 242                 struct nft_expr *dynset_expr;
 243
 244                 dynset_expr = nft_dynset_expr_alloc(ctx, set,
 245                                                     tb[NFTA_DYNSET_EXPR], 0);
 246                 if (IS_ERR(dynset_expr))
 247                         return PTR_ERR(dynset_expr);
 248
 249                 priv->num_exprs++;
 250                 priv->expr_array[0] = dynset_expr;
 251
 252                 if (set->num_exprs > 1 ||
 253                     (set->num_exprs == 1 &&
 254                      dynset_expr->ops != set->exprs[0]->ops)) {
 255                         err = -EOPNOTSUPP;
 256                         goto err_expr_free;
 257                 }
 258         } else if (tb[NFTA_DYNSET_EXPRESSIONS]) {
 259                 struct nft_expr *dynset_expr;
 260                 struct nlattr *tmp;
 261                 int left;
 262
 263                 if (!priv->expr)
 264                         return -EINVAL;
 265
 266                 i = 0;
 267                 nla_for_each_nested(tmp, tb[NFTA_DYNSET_EXPRESSIONS], left) {
 268                         if (i == NFT_SET_EXPR_MAX) {
 269                                 err = -E2BIG;
 270                                 goto err_expr_free;
 271                         }
 272                         if (nla_type(tmp) != NFTA_LIST_ELEM) {
 273                                 err = -EINVAL;
 274                                 goto err_expr_free;
 275                         }
 276                         dynset_expr = nft_dynset_expr_alloc(ctx, set, tmp, i);
 277                         if (IS_ERR(dynset_expr)) {
 278                                 err = PTR_ERR(dynset_expr);
 279                                 goto err_expr_free;
 280                         }
 281                         priv->expr_array[i] = dynset_expr;
 282                         priv->num_exprs++;
 283
 284                         if (set->num_exprs) {
 285                                 if (i >= set->num_exprs) {
 286                                         err = -EINVAL;
 287                                         goto err_expr_free;
 288                                 }
 289                                 if (dynset_expr->ops != set->exprs[i]->ops) {
 290                                         err = -EOPNOTSUPP;
 291                                         goto err_expr_free;
 292                                 }
 293                         }
 294                         i++;
 295                 }
 296                 if (set->num_exprs && set->num_exprs != i) {
 297                         err = -EOPNOTSUPP;
 298                         goto err_expr_free;
 299                 }
 300         } else if (set->num_exprs > 0) {
 301                 err = nft_set_elem_expr_clone(ctx, set, priv->expr_array);
 302                 if (err < 0)
 303                         return err;
 304
 305                 priv->num_exprs = set->num_exprs;
 306         }
 307
 308         nft_set_ext_prepare(&priv->tmpl);
 309         nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
 310         if (set->flags & NFT_SET_MAP)
 311                 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
 312
 313         if (priv->num_exprs)
 314                 nft_dynset_ext_add_expr(priv);
 315
 316         if (set->flags & NFT_SET_TIMEOUT &&
 317             (timeout || READ_ONCE(set->timeout)))
 318                 nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_TIMEOUT);
 319
 320         priv->timeout = timeout;
 321
 322         err = nf_tables_bind_set(ctx, set, &priv->binding);
 323         if (err < 0)
 324                 goto err_expr_free;
 325
 326         if (set->size == 0)
 327                 set->size = 0xffff;
 328
 329         priv->set = set;
 330         return 0;
 331
 332 err_expr_free:
 333         for (i = 0; i < priv->num_exprs; i++)
 334                 nft_expr_destroy(ctx, priv->expr_array[i]);
 335         return err;
 336 }
 337
 338 static void nft_dynset_deactivate(const struct nft_ctx *ctx,
 339                                   const struct nft_expr *expr,
 340                                   enum nft_trans_phase phase)
 341 {
 342         struct nft_dynset *priv = nft_expr_priv(expr);
 343
 344         nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 345 }
 346
 347 static void nft_dynset_activate(const struct nft_ctx *ctx,
 348                                 const struct nft_expr *expr)
 349 {
 350         struct nft_dynset *priv = nft_expr_priv(expr);
 351
 352         nf_tables_activate_set(ctx, priv->set);
 353 }
 354
 355 static void nft_dynset_destroy(const struct nft_ctx *ctx,
 356                                const struct nft_expr *expr)
 357 {
 358         struct nft_dynset *priv = nft_expr_priv(expr);
 359         int i;
 360
 361         for (i = 0; i < priv->num_exprs; i++)
 362                 nft_expr_destroy(ctx, priv->expr_array[i]);
 363
 364         nf_tables_destroy_set(ctx, priv->set);
 365 }
 366
 367 static int nft_dynset_dump(struct sk_buff *skb,
 368                            const struct nft_expr *expr, bool reset)
 369 {
 370         const struct nft_dynset *priv = nft_expr_priv(expr);
 371         u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
 372         int i;
 373
 374         if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
 375                 goto nla_put_failure;
 376         if (priv->set->flags & NFT_SET_MAP &&
 377             nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
 378                 goto nla_put_failure;
 379         if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
 380                 goto nla_put_failure;
 381         if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
 382                 goto nla_put_failure;
 383         if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
 384                          nf_jiffies64_to_msecs(priv->timeout),
 385                          NFTA_DYNSET_PAD))
 386                 goto nla_put_failure;
 387         if (priv->set->num_exprs == 0) {
 388                 if (priv->num_exprs == 1) {
 389                         if (nft_expr_dump(skb, NFTA_DYNSET_EXPR,
 390                                           priv->expr_array[0], reset))
 391                                 goto nla_put_failure;
 392                 } else if (priv->num_exprs > 1) {
 393                         struct nlattr *nest;
 394
 395                         nest = nla_nest_start_noflag(skb, NFTA_DYNSET_EXPRESSIONS);
 396                         if (!nest)
 397                                 goto nla_put_failure;
 398
 399                         for (i = 0; i < priv->num_exprs; i++) {
 400                                 if (nft_expr_dump(skb, NFTA_LIST_ELEM,
 401                                                   priv->expr_array[i], reset))
 402                                         goto nla_put_failure;
 403                         }
 404                         nla_nest_end(skb, nest);
 405                 }
 406         }
 407         if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
 408                 goto nla_put_failure;
 409         return 0;
 410
 411 nla_put_failure:
 412         return -1;
 413 }
 414
 415 static const struct nft_expr_ops nft_dynset_ops = {
 416         .type           = &nft_dynset_type,
 417         .size           = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
 418         .eval           = nft_dynset_eval,
 419         .init           = nft_dynset_init,
 420         .destroy        = nft_dynset_destroy,
 421         .activate       = nft_dynset_activate,
 422         .deactivate     = nft_dynset_deactivate,
 423         .dump           = nft_dynset_dump,
 424         .reduce         = NFT_REDUCE_READONLY,
 425 };
 426
 427 struct nft_expr_type nft_dynset_type __read_mostly = {
 428         .name           = "dynset",
 429         .ops            = &nft_dynset_ops,
 430         .policy         = nft_dynset_policy,
 431         .maxattr        = NFTA_DYNSET_MAX,
 432         .owner          = THIS_MODULE,
 433 };