net/core/sysctl_net_core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* -*- linux-c -*-
   3  * sysctl_net_core.c: sysctl interface to net core subsystem.
   4  *
   5  * Begun April 1, 1996, Mike Shaver.
   6  * Added /proc/sys/net/core directory entry (empty =) ). [MS]
   7  */
   8
   9 #include <linux/filter.h>
  10 #include <linux/mm.h>
  11 #include <linux/sysctl.h>
  12 #include <linux/module.h>
  13 #include <linux/socket.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/ratelimit.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19
  20 #include <net/ip.h>
  21 #include <net/sock.h>
  22 #include <net/net_ratelimit.h>
  23 #include <net/busy_poll.h>
  24 #include <net/pkt_sched.h>
  25
  26 static int two = 2;
  27 static int three = 3;
  28 static int int_3600 = 3600;
  29 static int min_sndbuf = SOCK_MIN_SNDBUF;
  30 static int min_rcvbuf = SOCK_MIN_RCVBUF;
  31 static int max_skb_frags = MAX_SKB_FRAGS;
  32 static long long_one __maybe_unused = 1;
  33 static long long_max __maybe_unused = LONG_MAX;
  34
  35 static int net_msg_warn;        /* Unused, but still a sysctl */
  36
  37 int sysctl_fb_tunnels_only_for_init_net __read_mostly = 0;
  38 EXPORT_SYMBOL(sysctl_fb_tunnels_only_for_init_net);
  39
  40 /* 0 - Keep current behavior:
  41  *     IPv4: inherit all current settings from init_net
  42  *     IPv6: reset all settings to default
  43  * 1 - Both inherit all current settings from init_net
  44  * 2 - Both reset all settings to default
  45  * 3 - Both inherit all settings from current netns
  46  */
  47 int sysctl_devconf_inherit_init_net __read_mostly;
  48 EXPORT_SYMBOL(sysctl_devconf_inherit_init_net);
  49
  50 #ifdef CONFIG_RPS
  51 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
  52                                 void *buffer, size_t *lenp, loff_t *ppos)
  53 {
  54         unsigned int orig_size, size;
  55         int ret, i;
  56         struct ctl_table tmp = {
  57                 .data = &size,
  58                 .maxlen = sizeof(size),
  59                 .mode = table->mode
  60         };
  61         struct rps_sock_flow_table *orig_sock_table, *sock_table;
  62         static DEFINE_MUTEX(sock_flow_mutex);
  63
  64         mutex_lock(&sock_flow_mutex);
  65
  66         orig_sock_table = rcu_dereference_protected(rps_sock_flow_table,
  67                                         lockdep_is_held(&sock_flow_mutex));
  68         size = orig_size = orig_sock_table ? orig_sock_table->mask + 1 : 0;
  69
  70         ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);
  71
  72         if (write) {
  73                 if (size) {
  74                         if (size > 1<<29) {
  75                                 /* Enforce limit to prevent overflow */
  76                                 mutex_unlock(&sock_flow_mutex);
  77                                 return -EINVAL;
  78                         }
  79                         size = roundup_pow_of_two(size);
  80                         if (size != orig_size) {
  81                                 sock_table =
  82                                     vmalloc(RPS_SOCK_FLOW_TABLE_SIZE(size));
  83                                 if (!sock_table) {
  84                                         mutex_unlock(&sock_flow_mutex);
  85                                         return -ENOMEM;
  86                                 }
  87                                 rps_cpu_mask = roundup_pow_of_two(nr_cpu_ids) - 1;
  88                                 sock_table->mask = size - 1;
  89                         } else
  90                                 sock_table = orig_sock_table;
  91
  92                         for (i = 0; i < size; i++)
  93                                 sock_table->ents[i] = RPS_NO_CPU;
  94                 } else
  95                         sock_table = NULL;
  96
  97                 if (sock_table != orig_sock_table) {
  98                         rcu_assign_pointer(rps_sock_flow_table, sock_table);
  99                         if (sock_table) {
 100                                 static_branch_inc(&rps_needed);
 101                                 static_branch_inc(&rfs_needed);
 102                         }
 103                         if (orig_sock_table) {
 104                                 static_branch_dec(&rps_needed);
 105                                 static_branch_dec(&rfs_needed);
 106                                 kvfree_rcu(orig_sock_table);
 107                         }
 108                 }
 109         }
 110
 111         mutex_unlock(&sock_flow_mutex);
 112
 113         return ret;
 114 }
 115 #endif /* CONFIG_RPS */
 116
 117 #ifdef CONFIG_NET_FLOW_LIMIT
 118 static DEFINE_MUTEX(flow_limit_update_mutex);
 119
 120 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
 121                                  void *buffer, size_t *lenp, loff_t *ppos)
 122 {
 123         struct sd_flow_limit *cur;
 124         struct softnet_data *sd;
 125         cpumask_var_t mask;
 126         int i, len, ret = 0;
 127
 128         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 129                 return -ENOMEM;
 130
 131         if (write) {
 132                 ret = cpumask_parse(buffer, mask);
 133                 if (ret)
 134                         goto done;
 135
 136                 mutex_lock(&flow_limit_update_mutex);
 137                 len = sizeof(*cur) + netdev_flow_limit_table_len;
 138                 for_each_possible_cpu(i) {
 139                         sd = &per_cpu(softnet_data, i);
 140                         cur = rcu_dereference_protected(sd->flow_limit,
 141                                      lockdep_is_held(&flow_limit_update_mutex));
 142                         if (cur && !cpumask_test_cpu(i, mask)) {
 143                                 RCU_INIT_POINTER(sd->flow_limit, NULL);
 144                                 kfree_rcu(cur);
 145                         } else if (!cur && cpumask_test_cpu(i, mask)) {
 146                                 cur = kzalloc_node(len, GFP_KERNEL,
 147                                                    cpu_to_node(i));
 148                                 if (!cur) {
 149                                         /* not unwinding previous changes */
 150                                         ret = -ENOMEM;
 151                                         goto write_unlock;
 152                                 }
 153                                 cur->num_buckets = netdev_flow_limit_table_len;
 154                                 rcu_assign_pointer(sd->flow_limit, cur);
 155                         }
 156                 }
 157 write_unlock:
 158                 mutex_unlock(&flow_limit_update_mutex);
 159         } else {
 160                 char kbuf[128];
 161
 162                 if (*ppos || !*lenp) {
 163                         *lenp = 0;
 164                         goto done;
 165                 }
 166
 167                 cpumask_clear(mask);
 168                 rcu_read_lock();
 169                 for_each_possible_cpu(i) {
 170                         sd = &per_cpu(softnet_data, i);
 171                         if (rcu_dereference(sd->flow_limit))
 172                                 cpumask_set_cpu(i, mask);
 173                 }
 174                 rcu_read_unlock();
 175
 176                 len = min(sizeof(kbuf) - 1, *lenp);
 177                 len = scnprintf(kbuf, len, "%*pb", cpumask_pr_args(mask));
 178                 if (!len) {
 179                         *lenp = 0;
 180                         goto done;
 181                 }
 182                 if (len < *lenp)
 183                         kbuf[len++] = '\n';
 184                 memcpy(buffer, kbuf, len);
 185                 *lenp = len;
 186                 *ppos += len;
 187         }
 188
 189 done:
 190         free_cpumask_var(mask);
 191         return ret;
 192 }
 193
 194 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
 195                                        void *buffer, size_t *lenp, loff_t *ppos)
 196 {
 197         unsigned int old, *ptr;
 198         int ret;
 199
 200         mutex_lock(&flow_limit_update_mutex);
 201
 202         ptr = table->data;
 203         old = *ptr;
 204         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 205         if (!ret && write && !is_power_of_2(*ptr)) {
 206                 *ptr = old;
 207                 ret = -EINVAL;
 208         }
 209
 210         mutex_unlock(&flow_limit_update_mutex);
 211         return ret;
 212 }
 213 #endif /* CONFIG_NET_FLOW_LIMIT */
 214
 215 #ifdef CONFIG_NET_SCHED
 216 static int set_default_qdisc(struct ctl_table *table, int write,
 217                              void *buffer, size_t *lenp, loff_t *ppos)
 218 {
 219         char id[IFNAMSIZ];
 220         struct ctl_table tbl = {
 221                 .data = id,
 222                 .maxlen = IFNAMSIZ,
 223         };
 224         int ret;
 225
 226         qdisc_get_default(id, IFNAMSIZ);
 227
 228         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 229         if (write && ret == 0)
 230                 ret = qdisc_set_default(id);
 231         return ret;
 232 }
 233 #endif
 234
 235 static int proc_do_dev_weight(struct ctl_table *table, int write,
 236                            void *buffer, size_t *lenp, loff_t *ppos)
 237 {
 238         int ret;
 239
 240         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 241         if (ret != 0)
 242                 return ret;
 243
 244         dev_rx_weight = weight_p * dev_weight_rx_bias;
 245         dev_tx_weight = weight_p * dev_weight_tx_bias;
 246
 247         return ret;
 248 }
 249
 250 static int proc_do_rss_key(struct ctl_table *table, int write,
 251                            void *buffer, size_t *lenp, loff_t *ppos)
 252 {
 253         struct ctl_table fake_table;
 254         char buf[NETDEV_RSS_KEY_LEN * 3];
 255
 256         snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
 257         fake_table.data = buf;
 258         fake_table.maxlen = sizeof(buf);
 259         return proc_dostring(&fake_table, write, buffer, lenp, ppos);
 260 }
 261
 262 #ifdef CONFIG_BPF_JIT
 263 static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
 264                                            void *buffer, size_t *lenp,
 265                                            loff_t *ppos)
 266 {
 267         int ret, jit_enable = *(int *)table->data;
 268         struct ctl_table tmp = *table;
 269
 270         if (write && !capable(CAP_SYS_ADMIN))
 271                 return -EPERM;
 272
 273         tmp.data = &jit_enable;
 274         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
 275         if (write && !ret) {
 276                 if (jit_enable < 2 ||
 277                     (jit_enable == 2 && bpf_dump_raw_ok(current_cred()))) {
 278                         *(int *)table->data = jit_enable;
 279                         if (jit_enable == 2)
 280                                 pr_warn("bpf_jit_enable = 2 was set! NEVER use this in production, only for JIT debugging!\n");
 281                 } else {
 282                         ret = -EPERM;
 283                 }
 284         }
 285         return ret;
 286 }
 287
 288 # ifdef CONFIG_HAVE_EBPF_JIT
 289 static int
 290 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 291                                     void *buffer, size_t *lenp, loff_t *ppos)
 292 {
 293         if (!capable(CAP_SYS_ADMIN))
 294                 return -EPERM;
 295
 296         return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 297 }
 298 # endif /* CONFIG_HAVE_EBPF_JIT */
 299
 300 static int
 301 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 302                                      void *buffer, size_t *lenp, loff_t *ppos)
 303 {
 304         if (!capable(CAP_SYS_ADMIN))
 305                 return -EPERM;
 306
 307         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 308 }
 309 #endif
 310
 311 static struct ctl_table net_core_table[] = {
 312         {
 313                 .procname       = "wmem_max",
 314                 .data           = &sysctl_wmem_max,
 315                 .maxlen         = sizeof(int),
 316                 .mode           = 0644,
 317                 .proc_handler   = proc_dointvec_minmax,
 318                 .extra1         = &min_sndbuf,
 319         },
 320         {
 321                 .procname       = "rmem_max",
 322                 .data           = &sysctl_rmem_max,
 323                 .maxlen         = sizeof(int),
 324                 .mode           = 0644,
 325                 .proc_handler   = proc_dointvec_minmax,
 326                 .extra1         = &min_rcvbuf,
 327         },
 328         {
 329                 .procname       = "wmem_default",
 330                 .data           = &sysctl_wmem_default,
 331                 .maxlen         = sizeof(int),
 332                 .mode           = 0644,
 333                 .proc_handler   = proc_dointvec_minmax,
 334                 .extra1         = &min_sndbuf,
 335         },
 336         {
 337                 .procname       = "rmem_default",
 338                 .data           = &sysctl_rmem_default,
 339                 .maxlen         = sizeof(int),
 340                 .mode           = 0644,
 341                 .proc_handler   = proc_dointvec_minmax,
 342                 .extra1         = &min_rcvbuf,
 343         },
 344         {
 345                 .procname       = "dev_weight",
 346                 .data           = &weight_p,
 347                 .maxlen         = sizeof(int),
 348                 .mode           = 0644,
 349                 .proc_handler   = proc_do_dev_weight,
 350         },
 351         {
 352                 .procname       = "dev_weight_rx_bias",
 353                 .data           = &dev_weight_rx_bias,
 354                 .maxlen         = sizeof(int),
 355                 .mode           = 0644,
 356                 .proc_handler   = proc_do_dev_weight,
 357         },
 358         {
 359                 .procname       = "dev_weight_tx_bias",
 360                 .data           = &dev_weight_tx_bias,
 361                 .maxlen         = sizeof(int),
 362                 .mode           = 0644,
 363                 .proc_handler   = proc_do_dev_weight,
 364         },
 365         {
 366                 .procname       = "netdev_max_backlog",
 367                 .data           = &netdev_max_backlog,
 368                 .maxlen         = sizeof(int),
 369                 .mode           = 0644,
 370                 .proc_handler   = proc_dointvec
 371         },
 372         {
 373                 .procname       = "netdev_rss_key",
 374                 .data           = &netdev_rss_key,
 375                 .maxlen         = sizeof(int),
 376                 .mode           = 0444,
 377                 .proc_handler   = proc_do_rss_key,
 378         },
 379 #ifdef CONFIG_BPF_JIT
 380         {
 381                 .procname       = "bpf_jit_enable",
 382                 .data           = &bpf_jit_enable,
 383                 .maxlen         = sizeof(int),
 384                 .mode           = 0644,
 385                 .proc_handler   = proc_dointvec_minmax_bpf_enable,
 386 # ifdef CONFIG_BPF_JIT_ALWAYS_ON
 387                 .extra1         = SYSCTL_ONE,
 388                 .extra2         = SYSCTL_ONE,
 389 # else
 390                 .extra1         = SYSCTL_ZERO,
 391                 .extra2         = &two,
 392 # endif
 393         },
 394 # ifdef CONFIG_HAVE_EBPF_JIT
 395         {
 396                 .procname       = "bpf_jit_harden",
 397                 .data           = &bpf_jit_harden,
 398                 .maxlen         = sizeof(int),
 399                 .mode           = 0600,
 400                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
 401                 .extra1         = SYSCTL_ZERO,
 402                 .extra2         = &two,
 403         },
 404         {
 405                 .procname       = "bpf_jit_kallsyms",
 406                 .data           = &bpf_jit_kallsyms,
 407                 .maxlen         = sizeof(int),
 408                 .mode           = 0600,
 409                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
 410                 .extra1         = SYSCTL_ZERO,
 411                 .extra2         = SYSCTL_ONE,
 412         },
 413 # endif
 414         {
 415                 .procname       = "bpf_jit_limit",
 416                 .data           = &bpf_jit_limit,
 417                 .maxlen         = sizeof(long),
 418                 .mode           = 0600,
 419                 .proc_handler   = proc_dolongvec_minmax_bpf_restricted,
 420                 .extra1         = &long_one,
 421                 .extra2         = &bpf_jit_limit_max,
 422         },
 423 #endif
 424         {
 425                 .procname       = "netdev_tstamp_prequeue",
 426                 .data           = &netdev_tstamp_prequeue,
 427                 .maxlen         = sizeof(int),
 428                 .mode           = 0644,
 429                 .proc_handler   = proc_dointvec
 430         },
 431         {
 432                 .procname       = "message_cost",
 433                 .data           = &net_ratelimit_state.interval,
 434                 .maxlen         = sizeof(int),
 435                 .mode           = 0644,
 436                 .proc_handler   = proc_dointvec_jiffies,
 437         },
 438         {
 439                 .procname       = "message_burst",
 440                 .data           = &net_ratelimit_state.burst,
 441                 .maxlen         = sizeof(int),
 442                 .mode           = 0644,
 443                 .proc_handler   = proc_dointvec,
 444         },
 445         {
 446                 .procname       = "optmem_max",
 447                 .data           = &sysctl_optmem_max,
 448                 .maxlen         = sizeof(int),
 449                 .mode           = 0644,
 450                 .proc_handler   = proc_dointvec
 451         },
 452         {
 453                 .procname       = "tstamp_allow_data",
 454                 .data           = &sysctl_tstamp_allow_data,
 455                 .maxlen         = sizeof(int),
 456                 .mode           = 0644,
 457                 .proc_handler   = proc_dointvec_minmax,
 458                 .extra1         = SYSCTL_ZERO,
 459                 .extra2         = SYSCTL_ONE
 460         },
 461 #ifdef CONFIG_RPS
 462         {
 463                 .procname       = "rps_sock_flow_entries",
 464                 .maxlen         = sizeof(int),
 465                 .mode           = 0644,
 466                 .proc_handler   = rps_sock_flow_sysctl
 467         },
 468 #endif
 469 #ifdef CONFIG_NET_FLOW_LIMIT
 470         {
 471                 .procname       = "flow_limit_cpu_bitmap",
 472                 .mode           = 0644,
 473                 .proc_handler   = flow_limit_cpu_sysctl
 474         },
 475         {
 476                 .procname       = "flow_limit_table_len",
 477                 .data           = &netdev_flow_limit_table_len,
 478                 .maxlen         = sizeof(int),
 479                 .mode           = 0644,
 480                 .proc_handler   = flow_limit_table_len_sysctl
 481         },
 482 #endif /* CONFIG_NET_FLOW_LIMIT */
 483 #ifdef CONFIG_NET_RX_BUSY_POLL
 484         {
 485                 .procname       = "busy_poll",
 486                 .data           = &sysctl_net_busy_poll,
 487                 .maxlen         = sizeof(unsigned int),
 488                 .mode           = 0644,
 489                 .proc_handler   = proc_dointvec_minmax,
 490                 .extra1         = SYSCTL_ZERO,
 491         },
 492         {
 493                 .procname       = "busy_read",
 494                 .data           = &sysctl_net_busy_read,
 495                 .maxlen         = sizeof(unsigned int),
 496                 .mode           = 0644,
 497                 .proc_handler   = proc_dointvec_minmax,
 498                 .extra1         = SYSCTL_ZERO,
 499         },
 500 #endif
 501 #ifdef CONFIG_NET_SCHED
 502         {
 503                 .procname       = "default_qdisc",
 504                 .mode           = 0644,
 505                 .maxlen         = IFNAMSIZ,
 506                 .proc_handler   = set_default_qdisc
 507         },
 508 #endif
 509         {
 510                 .procname       = "netdev_budget",
 511                 .data           = &netdev_budget,
 512                 .maxlen         = sizeof(int),
 513                 .mode           = 0644,
 514                 .proc_handler   = proc_dointvec
 515         },
 516         {
 517                 .procname       = "warnings",
 518                 .data           = &net_msg_warn,
 519                 .maxlen         = sizeof(int),
 520                 .mode           = 0644,
 521                 .proc_handler   = proc_dointvec
 522         },
 523         {
 524                 .procname       = "max_skb_frags",
 525                 .data           = &sysctl_max_skb_frags,
 526                 .maxlen         = sizeof(int),
 527                 .mode           = 0644,
 528                 .proc_handler   = proc_dointvec_minmax,
 529                 .extra1         = SYSCTL_ONE,
 530                 .extra2         = &max_skb_frags,
 531         },
 532         {
 533                 .procname       = "netdev_budget_usecs",
 534                 .data           = &netdev_budget_usecs,
 535                 .maxlen         = sizeof(unsigned int),
 536                 .mode           = 0644,
 537                 .proc_handler   = proc_dointvec_minmax,
 538                 .extra1         = SYSCTL_ZERO,
 539         },
 540         {
 541                 .procname       = "fb_tunnels_only_for_init_net",
 542                 .data           = &sysctl_fb_tunnels_only_for_init_net,
 543                 .maxlen         = sizeof(int),
 544                 .mode           = 0644,
 545                 .proc_handler   = proc_dointvec_minmax,
 546                 .extra1         = SYSCTL_ZERO,
 547                 .extra2         = &two,
 548         },
 549         {
 550                 .procname       = "devconf_inherit_init_net",
 551                 .data           = &sysctl_devconf_inherit_init_net,
 552                 .maxlen         = sizeof(int),
 553                 .mode           = 0644,
 554                 .proc_handler   = proc_dointvec_minmax,
 555                 .extra1         = SYSCTL_ZERO,
 556                 .extra2         = &three,
 557         },
 558         {
 559                 .procname       = "high_order_alloc_disable",
 560                 .data           = &net_high_order_alloc_disable_key.key,
 561                 .maxlen         = sizeof(net_high_order_alloc_disable_key),
 562                 .mode           = 0644,
 563                 .proc_handler   = proc_do_static_key,
 564         },
 565         {
 566                 .procname       = "gro_normal_batch",
 567                 .data           = &gro_normal_batch,
 568                 .maxlen         = sizeof(unsigned int),
 569                 .mode           = 0644,
 570                 .proc_handler   = proc_dointvec_minmax,
 571                 .extra1         = SYSCTL_ONE,
 572         },
 573         {
 574                 .procname       = "netdev_unregister_timeout_secs",
 575                 .data           = &netdev_unregister_timeout_secs,
 576                 .maxlen         = sizeof(unsigned int),
 577                 .mode           = 0644,
 578                 .proc_handler   = proc_dointvec_minmax,
 579                 .extra1         = SYSCTL_ONE,
 580                 .extra2         = &int_3600,
 581         },
 582         { }
 583 };
 584
 585 static struct ctl_table netns_core_table[] = {
 586         {
 587                 .procname       = "somaxconn",
 588                 .data           = &init_net.core.sysctl_somaxconn,
 589                 .maxlen         = sizeof(int),
 590                 .mode           = 0644,
 591                 .extra1         = SYSCTL_ZERO,
 592                 .proc_handler   = proc_dointvec_minmax
 593         },
 594         {
 595                 .procname       = "txrehash",
 596                 .data           = &init_net.core.sysctl_txrehash,
 597                 .maxlen         = sizeof(u8),
 598                 .mode           = 0644,
 599                 .extra1         = SYSCTL_ZERO,
 600                 .extra2         = SYSCTL_ONE,
 601                 .proc_handler   = proc_dou8vec_minmax,
 602         },
 603         { }
 604 };
 605
 606 static int __init fb_tunnels_only_for_init_net_sysctl_setup(char *str)
 607 {
 608         /* fallback tunnels for initns only */
 609         if (!strncmp(str, "initns", 6))
 610                 sysctl_fb_tunnels_only_for_init_net = 1;
 611         /* no fallback tunnels anywhere */
 612         else if (!strncmp(str, "none", 4))
 613                 sysctl_fb_tunnels_only_for_init_net = 2;
 614
 615         return 1;
 616 }
 617 __setup("fb_tunnels=", fb_tunnels_only_for_init_net_sysctl_setup);
 618
 619 static __net_init int sysctl_core_net_init(struct net *net)
 620 {
 621         struct ctl_table *tbl, *tmp;
 622
 623         tbl = netns_core_table;
 624         if (!net_eq(net, &init_net)) {
 625                 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
 626                 if (tbl == NULL)
 627                         goto err_dup;
 628
 629                 for (tmp = tbl; tmp->procname; tmp++)
 630                         tmp->data += (char *)net - (char *)&init_net;
 631
 632                 /* Don't export any sysctls to unprivileged users */
 633                 if (net->user_ns != &init_user_ns) {
 634                         tbl[0].procname = NULL;
 635                 }
 636         }
 637
 638         net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
 639         if (net->core.sysctl_hdr == NULL)
 640                 goto err_reg;
 641
 642         return 0;
 643
 644 err_reg:
 645         if (tbl != netns_core_table)
 646                 kfree(tbl);
 647 err_dup:
 648         return -ENOMEM;
 649 }
 650
 651 static __net_exit void sysctl_core_net_exit(struct net *net)
 652 {
 653         struct ctl_table *tbl;
 654
 655         tbl = net->core.sysctl_hdr->ctl_table_arg;
 656         unregister_net_sysctl_table(net->core.sysctl_hdr);
 657         BUG_ON(tbl == netns_core_table);
 658         kfree(tbl);
 659 }
 660
 661 static __net_initdata struct pernet_operations sysctl_core_ops = {
 662         .init = sysctl_core_net_init,
 663         .exit = sysctl_core_net_exit,
 664 };
 665
 666 static __init int sysctl_core_init(void)
 667 {
 668         register_net_sysctl(&init_net, "net/core", net_core_table);
 669         return register_pernet_subsys(&sysctl_core_ops);
 670 }
 671
 672 fs_initcall(sysctl_core_init);