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   1 From: Harsha Sharma <harshasharmaiitr@gmail.com>
   2 Date: Wed, 27 Dec 2017 00:59:00 +0530
   3 Subject: [PATCH] netfilter: nf_tables: allocate handle and delete objects via
   4  handle
   5
   6 This patch allows deletion of objects via unique handle which can be
   7 listed via '-a' option.
   8
   9 Signed-off-by: Harsha Sharma <harshasharmaiitr@gmail.com>
  10 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
  11 ---
  12
  13 --- a/include/net/netfilter/nf_tables.h
  14 +++ b/include/net/netfilter/nf_tables.h
  15 @@ -370,6 +370,7 @@ void nft_unregister_set(struct nft_set_t
  16   *     @list: table set list node
  17   *     @bindings: list of set bindings
  18   *     @name: name of the set
  19 + *     @handle: unique handle of the set
  20   *     @ktype: key type (numeric type defined by userspace, not used in the kernel)
  21   *     @dtype: data type (verdict or numeric type defined by userspace)
  22   *     @objtype: object type (see NFT_OBJECT_* definitions)
  23 @@ -392,6 +393,7 @@ struct nft_set {
  24         struct list_head                list;
  25         struct list_head                bindings;
  26         char                            *name;
  27 +       u64                             handle;
  28         u32                             ktype;
  29         u32                             dtype;
  30         u32                             objtype;
  31 @@ -942,6 +944,7 @@ unsigned int nft_do_chain(struct nft_pkt
  32   *     @objects: stateful objects in the table
  33   *     @flowtables: flow tables in the table
  34   *     @hgenerator: handle generator state
  35 + *     @handle: table handle
  36   *     @use: number of chain references to this table
  37   *     @flags: table flag (see enum nft_table_flags)
  38   *     @genmask: generation mask
  39 @@ -955,6 +958,7 @@ struct nft_table {
  40         struct list_head                objects;
  41         struct list_head                flowtables;
  42         u64                             hgenerator;
  43 +       u64                             handle;
  44         u32                             use;
  45         u16                             family:6,
  46                                         flags:8,
  47 @@ -979,9 +983,9 @@ int nft_verdict_dump(struct sk_buff *skb
  48   *     @name: name of this stateful object
  49   *     @genmask: generation mask
  50   *     @use: number of references to this stateful object
  51 - *     @data: object data, layout depends on type
  52 + *     @handle: unique object handle
  53   *     @ops: object operations
  54 - *     @data: pointer to object data
  55 + *     @data: object data, layout depends on type
  56   */
  57  struct nft_object {
  58         struct list_head                list;
  59 @@ -989,6 +993,7 @@ struct nft_object {
  60         struct nft_table                *table;
  61         u32                             genmask:2,
  62                                         use:30;
  63 +       u64                             handle;
  64         /* runtime data below here */
  65         const struct nft_object_ops     *ops ____cacheline_aligned;
  66         unsigned char                   data[]
  67 @@ -1070,6 +1075,7 @@ void nft_unregister_obj(struct nft_objec
  68   *     @ops_len: number of hooks in array
  69   *     @genmask: generation mask
  70   *     @use: number of references to this flow table
  71 + *     @handle: unique object handle
  72   *     @data: rhashtable and garbage collector
  73   *     @ops: array of hooks
  74   */
  75 @@ -1082,6 +1088,7 @@ struct nft_flowtable {
  76         int                             ops_len;
  77         u32                             genmask:2,
  78                                         use:30;
  79 +       u64                             handle;
  80         /* runtime data below here */
  81         struct nf_hook_ops              *ops ____cacheline_aligned;
  82         struct nf_flowtable             data;
  83 --- a/include/uapi/linux/netfilter/nf_tables.h
  84 +++ b/include/uapi/linux/netfilter/nf_tables.h
  85 @@ -174,6 +174,8 @@ enum nft_table_attributes {
  86         NFTA_TABLE_NAME,
  87         NFTA_TABLE_FLAGS,
  88         NFTA_TABLE_USE,
  89 +       NFTA_TABLE_HANDLE,
  90 +       NFTA_TABLE_PAD,
  91         __NFTA_TABLE_MAX
  92  };
  93  #define NFTA_TABLE_MAX         (__NFTA_TABLE_MAX - 1)
  94 @@ -317,6 +319,7 @@ enum nft_set_desc_attributes {
  95   * @NFTA_SET_GC_INTERVAL: garbage collection interval (NLA_U32)
  96   * @NFTA_SET_USERDATA: user data (NLA_BINARY)
  97   * @NFTA_SET_OBJ_TYPE: stateful object type (NLA_U32: NFT_OBJECT_*)
  98 + * @NFTA_SET_HANDLE: set handle (NLA_U64)
  99   */
 100  enum nft_set_attributes {
 101         NFTA_SET_UNSPEC,
 102 @@ -335,6 +338,7 @@ enum nft_set_attributes {
 103         NFTA_SET_USERDATA,
 104         NFTA_SET_PAD,
 105         NFTA_SET_OBJ_TYPE,
 106 +       NFTA_SET_HANDLE,
 107         __NFTA_SET_MAX
 108  };
 109  #define NFTA_SET_MAX           (__NFTA_SET_MAX - 1)
 110 @@ -1314,6 +1318,7 @@ enum nft_ct_helper_attributes {
 111   * @NFTA_OBJ_TYPE: stateful object type (NLA_U32)
 112   * @NFTA_OBJ_DATA: stateful object data (NLA_NESTED)
 113   * @NFTA_OBJ_USE: number of references to this expression (NLA_U32)
 114 + * @NFTA_OBJ_HANDLE: object handle (NLA_U64)
 115   */
 116  enum nft_object_attributes {
 117         NFTA_OBJ_UNSPEC,
 118 @@ -1322,6 +1327,8 @@ enum nft_object_attributes {
 119         NFTA_OBJ_TYPE,
 120         NFTA_OBJ_DATA,
 121         NFTA_OBJ_USE,
 122 +       NFTA_OBJ_HANDLE,
 123 +       NFTA_OBJ_PAD,
 124         __NFTA_OBJ_MAX
 125  };
 126  #define NFTA_OBJ_MAX           (__NFTA_OBJ_MAX - 1)
 127 @@ -1333,6 +1340,7 @@ enum nft_object_attributes {
 128   * @NFTA_FLOWTABLE_NAME: name of this flow table (NLA_STRING)
 129   * @NFTA_FLOWTABLE_HOOK: netfilter hook configuration(NLA_U32)
 130   * @NFTA_FLOWTABLE_USE: number of references to this flow table (NLA_U32)
 131 + * @NFTA_FLOWTABLE_HANDLE: object handle (NLA_U64)
 132   */
 133  enum nft_flowtable_attributes {
 134         NFTA_FLOWTABLE_UNSPEC,
 135 @@ -1340,6 +1348,8 @@ enum nft_flowtable_attributes {
 136         NFTA_FLOWTABLE_NAME,
 137         NFTA_FLOWTABLE_HOOK,
 138         NFTA_FLOWTABLE_USE,
 139 +       NFTA_FLOWTABLE_HANDLE,
 140 +       NFTA_FLOWTABLE_PAD,
 141         __NFTA_FLOWTABLE_MAX
 142  };
 143  #define NFTA_FLOWTABLE_MAX     (__NFTA_FLOWTABLE_MAX - 1)
 144 --- a/net/netfilter/nf_tables_api.c
 145 +++ b/net/netfilter/nf_tables_api.c
 146 @@ -26,6 +26,7 @@
 147  static LIST_HEAD(nf_tables_expressions);
 148  static LIST_HEAD(nf_tables_objects);
 149  static LIST_HEAD(nf_tables_flowtables);
 150 +static u64 table_handle;
 151
 152  static void nft_ctx_init(struct nft_ctx *ctx,
 153                          struct net *net,
 154 @@ -376,6 +377,20 @@ static struct nft_table *nft_table_looku
 155         return NULL;
 156  }
 157
 158 +static struct nft_table *nft_table_lookup_byhandle(const struct net *net,
 159 +                                                  const struct nlattr *nla,
 160 +                                                  u8 genmask)
 161 +{
 162 +       struct nft_table *table;
 163 +
 164 +       list_for_each_entry(table, &net->nft.tables, list) {
 165 +               if (be64_to_cpu(nla_get_be64(nla)) == table->handle &&
 166 +                   nft_active_genmask(table, genmask))
 167 +                       return table;
 168 +       }
 169 +       return NULL;
 170 +}
 171 +
 172  static struct nft_table *nf_tables_table_lookup(const struct net *net,
 173                                                 const struct nlattr *nla,
 174                                                 u8 family, u8 genmask)
 175 @@ -392,6 +407,22 @@ static struct nft_table *nf_tables_table
 176         return ERR_PTR(-ENOENT);
 177  }
 178
 179 +static struct nft_table *nf_tables_table_lookup_byhandle(const struct net *net,
 180 +                                                        const struct nlattr *nla,
 181 +                                                        u8 genmask)
 182 +{
 183 +       struct nft_table *table;
 184 +
 185 +       if (nla == NULL)
 186 +               return ERR_PTR(-EINVAL);
 187 +
 188 +       table = nft_table_lookup_byhandle(net, nla, genmask);
 189 +       if (table != NULL)
 190 +               return table;
 191 +
 192 +       return ERR_PTR(-ENOENT);
 193 +}
 194 +
 195  static inline u64 nf_tables_alloc_handle(struct nft_table *table)
 196  {
 197         return ++table->hgenerator;
 198 @@ -438,6 +469,7 @@ static const struct nla_policy nft_table
 199         [NFTA_TABLE_NAME]       = { .type = NLA_STRING,
 200                                     .len = NFT_TABLE_MAXNAMELEN - 1 },
 201         [NFTA_TABLE_FLAGS]      = { .type = NLA_U32 },
 202 +       [NFTA_TABLE_HANDLE]     = { .type = NLA_U64 },
 203  };
 204
 205  static int nf_tables_fill_table_info(struct sk_buff *skb, struct net *net,
 206 @@ -459,7 +491,9 @@ static int nf_tables_fill_table_info(str
 207
 208         if (nla_put_string(skb, NFTA_TABLE_NAME, table->name) ||
 209             nla_put_be32(skb, NFTA_TABLE_FLAGS, htonl(table->flags)) ||
 210 -           nla_put_be32(skb, NFTA_TABLE_USE, htonl(table->use)))
 211 +           nla_put_be32(skb, NFTA_TABLE_USE, htonl(table->use)) ||
 212 +           nla_put_be64(skb, NFTA_TABLE_HANDLE, cpu_to_be64(table->handle),
 213 +                        NFTA_TABLE_PAD))
 214                 goto nla_put_failure;
 215
 216         nlmsg_end(skb, nlh);
 217 @@ -718,6 +752,7 @@ static int nf_tables_newtable(struct net
 218         INIT_LIST_HEAD(&table->flowtables);
 219         table->family = family;
 220         table->flags = flags;
 221 +       table->handle = ++table_handle;
 222
 223         nft_ctx_init(&ctx, net, skb, nlh, family, table, NULL, nla);
 224         err = nft_trans_table_add(&ctx, NFT_MSG_NEWTABLE);
 225 @@ -835,11 +870,18 @@ static int nf_tables_deltable(struct net
 226         struct nft_ctx ctx;
 227
 228         nft_ctx_init(&ctx, net, skb, nlh, 0, NULL, NULL, nla);
 229 -       if (family == AF_UNSPEC || nla[NFTA_TABLE_NAME] == NULL)
 230 +       if (family == AF_UNSPEC ||
 231 +           (!nla[NFTA_TABLE_NAME] && !nla[NFTA_TABLE_HANDLE]))
 232                 return nft_flush(&ctx, family);
 233
 234 -       table = nf_tables_table_lookup(net, nla[NFTA_TABLE_NAME], family,
 235 -                                      genmask);
 236 +       if (nla[NFTA_TABLE_HANDLE])
 237 +               table = nf_tables_table_lookup_byhandle(net,
 238 +                                                       nla[NFTA_TABLE_HANDLE],
 239 +                                                       genmask);
 240 +       else
 241 +               table = nf_tables_table_lookup(net, nla[NFTA_TABLE_NAME],
 242 +                                              family, genmask);
 243 +
 244         if (IS_ERR(table))
 245                 return PTR_ERR(table);
 246
 247 @@ -1596,6 +1638,7 @@ static int nf_tables_delchain(struct net
 248         struct nft_rule *rule;
 249         int family = nfmsg->nfgen_family;
 250         struct nft_ctx ctx;
 251 +       u64 handle;
 252         u32 use;
 253         int err;
 254
 255 @@ -1604,7 +1647,12 @@ static int nf_tables_delchain(struct net
 256         if (IS_ERR(table))
 257                 return PTR_ERR(table);
 258
 259 -       chain = nf_tables_chain_lookup(table, nla[NFTA_CHAIN_NAME], genmask);
 260 +       if (nla[NFTA_CHAIN_HANDLE]) {
 261 +               handle = be64_to_cpu(nla_get_be64(nla[NFTA_CHAIN_HANDLE]));
 262 +               chain = nf_tables_chain_lookup_byhandle(table, handle, genmask);
 263 +       } else {
 264 +               chain = nf_tables_chain_lookup(table, nla[NFTA_CHAIN_NAME], genmask);
 265 +       }
 266         if (IS_ERR(chain))
 267                 return PTR_ERR(chain);
 268
 269 @@ -2579,6 +2627,7 @@ static const struct nla_policy nft_set_p
 270         [NFTA_SET_USERDATA]             = { .type = NLA_BINARY,
 271                                             .len  = NFT_USERDATA_MAXLEN },
 272         [NFTA_SET_OBJ_TYPE]             = { .type = NLA_U32 },
 273 +       [NFTA_SET_HANDLE]               = { .type = NLA_U64 },
 274  };
 275
 276  static const struct nla_policy nft_set_desc_policy[NFTA_SET_DESC_MAX + 1] = {
 277 @@ -2622,6 +2671,22 @@ static struct nft_set *nf_tables_set_loo
 278         return ERR_PTR(-ENOENT);
 279  }
 280
 281 +static struct nft_set *nf_tables_set_lookup_byhandle(const struct nft_table *table,
 282 +                                                    const struct nlattr *nla, u8 genmask)
 283 +{
 284 +       struct nft_set *set;
 285 +
 286 +       if (nla == NULL)
 287 +               return ERR_PTR(-EINVAL);
 288 +
 289 +       list_for_each_entry(set, &table->sets, list) {
 290 +               if (be64_to_cpu(nla_get_be64(nla)) == set->handle &&
 291 +                   nft_active_genmask(set, genmask))
 292 +                       return set;
 293 +       }
 294 +       return ERR_PTR(-ENOENT);
 295 +}
 296 +
 297  static struct nft_set *nf_tables_set_lookup_byid(const struct net *net,
 298                                                  const struct nlattr *nla,
 299                                                  u8 genmask)
 300 @@ -2738,6 +2803,9 @@ static int nf_tables_fill_set(struct sk_
 301                 goto nla_put_failure;
 302         if (nla_put_string(skb, NFTA_SET_NAME, set->name))
 303                 goto nla_put_failure;
 304 +       if (nla_put_be64(skb, NFTA_SET_HANDLE, cpu_to_be64(set->handle),
 305 +                        NFTA_SET_PAD))
 306 +               goto nla_put_failure;
 307         if (set->flags != 0)
 308                 if (nla_put_be32(skb, NFTA_SET_FLAGS, htonl(set->flags)))
 309                         goto nla_put_failure;
 310 @@ -3149,6 +3217,7 @@ static int nf_tables_newset(struct net *
 311         set->udata  = udata;
 312         set->timeout = timeout;
 313         set->gc_int = gc_int;
 314 +       set->handle = nf_tables_alloc_handle(table);
 315
 316         err = ops->init(set, &desc, nla);
 317         if (err < 0)
 318 @@ -3208,7 +3277,10 @@ static int nf_tables_delset(struct net *
 319         if (err < 0)
 320                 return err;
 321
 322 -       set = nf_tables_set_lookup(ctx.table, nla[NFTA_SET_NAME], genmask);
 323 +       if (nla[NFTA_SET_HANDLE])
 324 +               set = nf_tables_set_lookup_byhandle(ctx.table, nla[NFTA_SET_HANDLE], genmask);
 325 +       else
 326 +               set = nf_tables_set_lookup(ctx.table, nla[NFTA_SET_NAME], genmask);
 327         if (IS_ERR(set))
 328                 return PTR_ERR(set);
 329
 330 @@ -4271,6 +4343,21 @@ struct nft_object *nf_tables_obj_lookup(
 331  }
 332  EXPORT_SYMBOL_GPL(nf_tables_obj_lookup);
 333
 334 +struct nft_object *nf_tables_obj_lookup_byhandle(const struct nft_table *table,
 335 +                                                const struct nlattr *nla,
 336 +                                                u32 objtype, u8 genmask)
 337 +{
 338 +       struct nft_object *obj;
 339 +
 340 +       list_for_each_entry(obj, &table->objects, list) {
 341 +               if (be64_to_cpu(nla_get_be64(nla)) == obj->handle &&
 342 +                   objtype == obj->ops->type->type &&
 343 +                   nft_active_genmask(obj, genmask))
 344 +                       return obj;
 345 +       }
 346 +       return ERR_PTR(-ENOENT);
 347 +}
 348 +
 349  static const struct nla_policy nft_obj_policy[NFTA_OBJ_MAX + 1] = {
 350         [NFTA_OBJ_TABLE]        = { .type = NLA_STRING,
 351                                     .len = NFT_TABLE_MAXNAMELEN - 1 },
 352 @@ -4278,6 +4365,7 @@ static const struct nla_policy nft_obj_p
 353                                     .len = NFT_OBJ_MAXNAMELEN - 1 },
 354         [NFTA_OBJ_TYPE]         = { .type = NLA_U32 },
 355         [NFTA_OBJ_DATA]         = { .type = NLA_NESTED },
 356 +       [NFTA_OBJ_HANDLE]       = { .type = NLA_U64},
 357  };
 358
 359  static struct nft_object *nft_obj_init(const struct nft_ctx *ctx,
 360 @@ -4425,6 +4513,8 @@ static int nf_tables_newobj(struct net *
 361                 goto err1;
 362         }
 363         obj->table = table;
 364 +       obj->handle = nf_tables_alloc_handle(table);
 365 +
 366         obj->name = nla_strdup(nla[NFTA_OBJ_NAME], GFP_KERNEL);
 367         if (!obj->name) {
 368                 err = -ENOMEM;
 369 @@ -4471,7 +4561,9 @@ static int nf_tables_fill_obj_info(struc
 370             nla_put_string(skb, NFTA_OBJ_NAME, obj->name) ||
 371             nla_put_be32(skb, NFTA_OBJ_TYPE, htonl(obj->ops->type->type)) ||
 372             nla_put_be32(skb, NFTA_OBJ_USE, htonl(obj->use)) ||
 373 -           nft_object_dump(skb, NFTA_OBJ_DATA, obj, reset))
 374 +           nft_object_dump(skb, NFTA_OBJ_DATA, obj, reset) ||
 375 +           nla_put_be64(skb, NFTA_OBJ_HANDLE, cpu_to_be64(obj->handle),
 376 +                        NFTA_OBJ_PAD))
 377                 goto nla_put_failure;
 378
 379         nlmsg_end(skb, nlh);
 380 @@ -4669,7 +4761,7 @@ static int nf_tables_delobj(struct net *
 381         u32 objtype;
 382
 383         if (!nla[NFTA_OBJ_TYPE] ||
 384 -           !nla[NFTA_OBJ_NAME])
 385 +           (!nla[NFTA_OBJ_NAME] && !nla[NFTA_OBJ_HANDLE]))
 386                 return -EINVAL;
 387
 388         table = nf_tables_table_lookup(net, nla[NFTA_OBJ_TABLE], family,
 389 @@ -4678,7 +4770,12 @@ static int nf_tables_delobj(struct net *
 390                 return PTR_ERR(table);
 391
 392         objtype = ntohl(nla_get_be32(nla[NFTA_OBJ_TYPE]));
 393 -       obj = nf_tables_obj_lookup(table, nla[NFTA_OBJ_NAME], objtype, genmask);
 394 +       if (nla[NFTA_OBJ_HANDLE])
 395 +               obj = nf_tables_obj_lookup_byhandle(table, nla[NFTA_OBJ_HANDLE],
 396 +                                                   objtype, genmask);
 397 +       else
 398 +               obj = nf_tables_obj_lookup(table, nla[NFTA_OBJ_NAME],
 399 +                                          objtype, genmask);
 400         if (IS_ERR(obj))
 401                 return PTR_ERR(obj);
 402         if (obj->use > 0)
 403 @@ -4750,6 +4847,7 @@ static const struct nla_policy nft_flowt
 404         [NFTA_FLOWTABLE_NAME]           = { .type = NLA_STRING,
 405                                             .len = NFT_NAME_MAXLEN - 1 },
 406         [NFTA_FLOWTABLE_HOOK]           = { .type = NLA_NESTED },
 407 +       [NFTA_FLOWTABLE_HANDLE]         = { .type = NLA_U64 },
 408  };
 409
 410  struct nft_flowtable *nf_tables_flowtable_lookup(const struct nft_table *table,
 411 @@ -4767,6 +4865,20 @@ struct nft_flowtable *nf_tables_flowtabl
 412  }
 413  EXPORT_SYMBOL_GPL(nf_tables_flowtable_lookup);
 414
 415 +struct nft_flowtable *
 416 +nf_tables_flowtable_lookup_byhandle(const struct nft_table *table,
 417 +                                   const struct nlattr *nla, u8 genmask)
 418 +{
 419 +       struct nft_flowtable *flowtable;
 420 +
 421 +       list_for_each_entry(flowtable, &table->flowtables, list) {
 422 +               if (be64_to_cpu(nla_get_be64(nla)) == flowtable->handle &&
 423 +                   nft_active_genmask(flowtable, genmask))
 424 +                       return flowtable;
 425 +       }
 426 +       return ERR_PTR(-ENOENT);
 427 +}
 428 +
 429  #define NFT_FLOWTABLE_DEVICE_MAX       8
 430
 431  static int nf_tables_parse_devices(const struct nft_ctx *ctx,
 432 @@ -4975,6 +5087,8 @@ static int nf_tables_newflowtable(struct
 433                 return -ENOMEM;
 434
 435         flowtable->table = table;
 436 +       flowtable->handle = nf_tables_alloc_handle(table);
 437 +
 438         flowtable->name = nla_strdup(nla[NFTA_FLOWTABLE_NAME], GFP_KERNEL);
 439         if (!flowtable->name) {
 440                 err = -ENOMEM;
 441 @@ -5049,8 +5163,14 @@ static int nf_tables_delflowtable(struct
 442         if (IS_ERR(table))
 443                 return PTR_ERR(table);
 444
 445 -       flowtable = nf_tables_flowtable_lookup(table, nla[NFTA_FLOWTABLE_NAME],
 446 -                                              genmask);
 447 +       if (nla[NFTA_FLOWTABLE_HANDLE])
 448 +               flowtable = nf_tables_flowtable_lookup_byhandle(table,
 449 +                                                               nla[NFTA_FLOWTABLE_HANDLE],
 450 +                                                               genmask);
 451 +       else
 452 +               flowtable = nf_tables_flowtable_lookup(table,
 453 +                                                      nla[NFTA_FLOWTABLE_NAME],
 454 +                                                      genmask);
 455         if (IS_ERR(flowtable))
 456                  return PTR_ERR(flowtable);
 457         if (flowtable->use > 0)
 458 @@ -5083,7 +5203,9 @@ static int nf_tables_fill_flowtable_info
 459
 460         if (nla_put_string(skb, NFTA_FLOWTABLE_TABLE, flowtable->table->name) ||
 461             nla_put_string(skb, NFTA_FLOWTABLE_NAME, flowtable->name) ||
 462 -           nla_put_be32(skb, NFTA_FLOWTABLE_USE, htonl(flowtable->use)))
 463 +           nla_put_be32(skb, NFTA_FLOWTABLE_USE, htonl(flowtable->use)) ||
 464 +           nla_put_be64(skb, NFTA_FLOWTABLE_HANDLE, cpu_to_be64(flowtable->handle),
 465 +                        NFTA_FLOWTABLE_PAD))
 466                 goto nla_put_failure;
 467
 468         nest = nla_nest_start(skb, NFTA_FLOWTABLE_HOOK);