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