linux/net/netfilter/nft_dynset.c
<<
>>
Prefs
   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
  15struct 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
  29static 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
  47static 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
  72err2:
  73        nft_set_elem_destroy(set, elem, false);
  74err1:
  75        if (set->size)
  76                atomic_dec(&set->nelems);
  77        return NULL;
  78}
  79
  80void 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
 112static 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
 124static struct nft_expr *
 125nft_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
 142err_dynset_expr:
 143        nft_expr_destroy(ctx, expr);
 144        return ERR_PTR(err);
 145}
 146
 147static 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
 160static int nft_dynset_init(const struct nft_ctx *ctx,
 161                           const struct nft_expr *expr,
 162                           const struct nlattr * const tb[])
 163{
 164        struct nftables_pernet *nft_net = nft_pernet(ctx->net);
 165        struct nft_dynset *priv = nft_expr_priv(expr);
 166        u8 genmask = nft_genmask_next(ctx->net);
 167        struct nft_set *set;
 168        u64 timeout;
 169        int err, i;
 170
 171        lockdep_assert_held(&nft_net->commit_mutex);
 172
 173        if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
 174            tb[NFTA_DYNSET_OP] == NULL ||
 175            tb[NFTA_DYNSET_SREG_KEY] == NULL)
 176                return -EINVAL;
 177
 178        if (tb[NFTA_DYNSET_FLAGS]) {
 179                u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
 180                if (flags & ~(NFT_DYNSET_F_INV | NFT_DYNSET_F_EXPR))
 181                        return -EOPNOTSUPP;
 182                if (flags & NFT_DYNSET_F_INV)
 183                        priv->invert = true;
 184                if (flags & NFT_DYNSET_F_EXPR)
 185                        priv->expr = true;
 186        }
 187
 188        set = nft_set_lookup_global(ctx->net, ctx->table,
 189                                    tb[NFTA_DYNSET_SET_NAME],
 190                                    tb[NFTA_DYNSET_SET_ID], genmask);
 191        if (IS_ERR(set))
 192                return PTR_ERR(set);
 193
 194        if (set->ops->update == NULL)
 195                return -EOPNOTSUPP;
 196
 197        if (set->flags & NFT_SET_CONSTANT)
 198                return -EBUSY;
 199
 200        priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
 201        if (priv->op > NFT_DYNSET_OP_DELETE)
 202                return -EOPNOTSUPP;
 203
 204        timeout = 0;
 205        if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
 206                if (!(set->flags & NFT_SET_TIMEOUT))
 207                        return -EOPNOTSUPP;
 208
 209                err = nf_msecs_to_jiffies64(tb[NFTA_DYNSET_TIMEOUT], &timeout);
 210                if (err)
 211                        return err;
 212        }
 213
 214        err = nft_parse_register_load(tb[NFTA_DYNSET_SREG_KEY], &priv->sreg_key,
 215                                      set->klen);
 216        if (err < 0)
 217                return err;
 218
 219        if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
 220                if (!(set->flags & NFT_SET_MAP))
 221                        return -EOPNOTSUPP;
 222                if (set->dtype == NFT_DATA_VERDICT)
 223                        return -EOPNOTSUPP;
 224
 225                err = nft_parse_register_load(tb[NFTA_DYNSET_SREG_DATA],
 226                                              &priv->sreg_data, set->dlen);
 227                if (err < 0)
 228                        return err;
 229        } else if (set->flags & NFT_SET_MAP)
 230                return -EINVAL;
 231
 232        if ((tb[NFTA_DYNSET_EXPR] || tb[NFTA_DYNSET_EXPRESSIONS]) &&
 233            !(set->flags & NFT_SET_EVAL))
 234                return -EINVAL;
 235
 236        if (tb[NFTA_DYNSET_EXPR]) {
 237                struct nft_expr *dynset_expr;
 238
 239                dynset_expr = nft_dynset_expr_alloc(ctx, set,
 240                                                    tb[NFTA_DYNSET_EXPR], 0);
 241                if (IS_ERR(dynset_expr))
 242                        return PTR_ERR(dynset_expr);
 243
 244                priv->num_exprs++;
 245                priv->expr_array[0] = dynset_expr;
 246
 247                if (set->num_exprs > 1 ||
 248                    (set->num_exprs == 1 &&
 249                     dynset_expr->ops != set->exprs[0]->ops)) {
 250                        err = -EOPNOTSUPP;
 251                        goto err_expr_free;
 252                }
 253        } else if (tb[NFTA_DYNSET_EXPRESSIONS]) {
 254                struct nft_expr *dynset_expr;
 255                struct nlattr *tmp;
 256                int left;
 257
 258                if (!priv->expr)
 259                        return -EINVAL;
 260
 261                i = 0;
 262                nla_for_each_nested(tmp, tb[NFTA_DYNSET_EXPRESSIONS], left) {
 263                        if (i == NFT_SET_EXPR_MAX) {
 264                                err = -E2BIG;
 265                                goto err_expr_free;
 266                        }
 267                        if (nla_type(tmp) != NFTA_LIST_ELEM) {
 268                                err = -EINVAL;
 269                                goto err_expr_free;
 270                        }
 271                        dynset_expr = nft_dynset_expr_alloc(ctx, set, tmp, i);
 272                        if (IS_ERR(dynset_expr)) {
 273                                err = PTR_ERR(dynset_expr);
 274                                goto err_expr_free;
 275                        }
 276                        priv->expr_array[i] = dynset_expr;
 277                        priv->num_exprs++;
 278
 279                        if (set->num_exprs &&
 280                            dynset_expr->ops != set->exprs[i]->ops) {
 281                                err = -EOPNOTSUPP;
 282                                goto err_expr_free;
 283                        }
 284                        i++;
 285                }
 286                if (set->num_exprs && set->num_exprs != i) {
 287                        err = -EOPNOTSUPP;
 288                        goto err_expr_free;
 289                }
 290        } else if (set->num_exprs > 0) {
 291                err = nft_set_elem_expr_clone(ctx, set, priv->expr_array);
 292                if (err < 0)
 293                        return err;
 294
 295                priv->num_exprs = set->num_exprs;
 296        }
 297
 298        nft_set_ext_prepare(&priv->tmpl);
 299        nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
 300        if (set->flags & NFT_SET_MAP)
 301                nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
 302
 303        if (priv->num_exprs)
 304                nft_dynset_ext_add_expr(priv);
 305
 306        if (set->flags & NFT_SET_TIMEOUT) {
 307                if (timeout || set->timeout) {
 308                        nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_TIMEOUT);
 309                        nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
 310                }
 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
 325err_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
 331static 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
 340static 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
 348static 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
 360static 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->set->num_exprs == 0) {
 380                if (priv->num_exprs == 1) {
 381                        if (nft_expr_dump(skb, NFTA_DYNSET_EXPR,
 382                                          priv->expr_array[0]))
 383                                goto nla_put_failure;
 384                } else if (priv->num_exprs > 1) {
 385                        struct nlattr *nest;
 386
 387                        nest = nla_nest_start_noflag(skb, NFTA_DYNSET_EXPRESSIONS);
 388                        if (!nest)
 389                                goto nla_put_failure;
 390
 391                        for (i = 0; i < priv->num_exprs; i++) {
 392                                if (nft_expr_dump(skb, NFTA_LIST_ELEM,
 393                                                  priv->expr_array[i]))
 394                                        goto nla_put_failure;
 395                        }
 396                        nla_nest_end(skb, nest);
 397                }
 398        }
 399        if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
 400                goto nla_put_failure;
 401        return 0;
 402
 403nla_put_failure:
 404        return -1;
 405}
 406
 407static const struct nft_expr_ops nft_dynset_ops = {
 408        .type           = &nft_dynset_type,
 409        .size           = NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
 410        .eval           = nft_dynset_eval,
 411        .init           = nft_dynset_init,
 412        .destroy        = nft_dynset_destroy,
 413        .activate       = nft_dynset_activate,
 414        .deactivate     = nft_dynset_deactivate,
 415        .dump           = nft_dynset_dump,
 416        .reduce         = NFT_REDUCE_READONLY,
 417};
 418
 419struct nft_expr_type nft_dynset_type __read_mostly = {
 420        .name           = "dynset",
 421        .ops            = &nft_dynset_ops,
 422        .policy         = nft_dynset_policy,
 423        .maxattr        = NFTA_DYNSET_MAX,
 424        .owner          = THIS_MODULE,
 425};
 426