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 __maybe_unused = 2;
  26 static int min_sndbuf = SOCK_MIN_SNDBUF;
  27 static int min_rcvbuf = SOCK_MIN_RCVBUF;
  28 static int max_skb_frags = MAX_SKB_FRAGS;
  29 static long long_one __maybe_unused = 1;
  30 static long long_max __maybe_unused = LONG_MAX;
  31
  32 static int net_msg_warn;        /* Unused, but still a sysctl */
  33
  34 int sysctl_fb_tunnels_only_for_init_net __read_mostly = 0;
  35 EXPORT_SYMBOL(sysctl_fb_tunnels_only_for_init_net);
  36
  37 /* 0 - Keep current behavior:
  38  *     IPv4: inherit all current settings from init_net
  39  *     IPv6: reset all settings to default
  40  * 1 - Both inherit all current settings from init_net
  41  * 2 - Both reset all settings to default
  42  */
  43 int sysctl_devconf_inherit_init_net __read_mostly;
  44 EXPORT_SYMBOL(sysctl_devconf_inherit_init_net);
  45
  46 #ifdef CONFIG_RPS
  47 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
  48                                 void __user *buffer, size_t *lenp, loff_t *ppos)
  49 {
  50         unsigned int orig_size, size;
  51         int ret, i;
  52         struct ctl_table tmp = {
  53                 .data = &size,
  54                 .maxlen = sizeof(size),
  55                 .mode = table->mode
  56         };
  57         struct rps_sock_flow_table *orig_sock_table, *sock_table;
  58         static DEFINE_MUTEX(sock_flow_mutex);
  59
  60         mutex_lock(&sock_flow_mutex);
  61
  62         orig_sock_table = rcu_dereference_protected(rps_sock_flow_table,
  63                                         lockdep_is_held(&sock_flow_mutex));
  64         size = orig_size = orig_sock_table ? orig_sock_table->mask + 1 : 0;
  65
  66         ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);
  67
  68         if (write) {
  69                 if (size) {
  70                         if (size > 1<<29) {
  71                                 /* Enforce limit to prevent overflow */
  72                                 mutex_unlock(&sock_flow_mutex);
  73                                 return -EINVAL;
  74                         }
  75                         size = roundup_pow_of_two(size);
  76                         if (size != orig_size) {
  77                                 sock_table =
  78                                     vmalloc(RPS_SOCK_FLOW_TABLE_SIZE(size));
  79                                 if (!sock_table) {
  80                                         mutex_unlock(&sock_flow_mutex);
  81                                         return -ENOMEM;
  82                                 }
  83                                 rps_cpu_mask = roundup_pow_of_two(nr_cpu_ids) - 1;
  84                                 sock_table->mask = size - 1;
  85                         } else
  86                                 sock_table = orig_sock_table;
  87
  88                         for (i = 0; i < size; i++)
  89                                 sock_table->ents[i] = RPS_NO_CPU;
  90                 } else
  91                         sock_table = NULL;
  92
  93                 if (sock_table != orig_sock_table) {
  94                         rcu_assign_pointer(rps_sock_flow_table, sock_table);
  95                         if (sock_table) {
  96                                 static_branch_inc(&rps_needed);
  97                                 static_branch_inc(&rfs_needed);
  98                         }
  99                         if (orig_sock_table) {
 100                                 static_branch_dec(&rps_needed);
 101                                 static_branch_dec(&rfs_needed);
 102                                 synchronize_rcu();
 103                                 vfree(orig_sock_table);
 104                         }
 105                 }
 106         }
 107
 108         mutex_unlock(&sock_flow_mutex);
 109
 110         return ret;
 111 }
 112 #endif /* CONFIG_RPS */
 113
 114 #ifdef CONFIG_NET_FLOW_LIMIT
 115 static DEFINE_MUTEX(flow_limit_update_mutex);
 116
 117 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
 118                                  void __user *buffer, size_t *lenp,
 119                                  loff_t *ppos)
 120 {
 121         struct sd_flow_limit *cur;
 122         struct softnet_data *sd;
 123         cpumask_var_t mask;
 124         int i, len, ret = 0;
 125
 126         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 127                 return -ENOMEM;
 128
 129         if (write) {
 130                 ret = cpumask_parse_user(buffer, *lenp, mask);
 131                 if (ret)
 132                         goto done;
 133
 134                 mutex_lock(&flow_limit_update_mutex);
 135                 len = sizeof(*cur) + netdev_flow_limit_table_len;
 136                 for_each_possible_cpu(i) {
 137                         sd = &per_cpu(softnet_data, i);
 138                         cur = rcu_dereference_protected(sd->flow_limit,
 139                                      lockdep_is_held(&flow_limit_update_mutex));
 140                         if (cur && !cpumask_test_cpu(i, mask)) {
 141                                 RCU_INIT_POINTER(sd->flow_limit, NULL);
 142                                 synchronize_rcu();
 143                                 kfree(cur);
 144                         } else if (!cur && cpumask_test_cpu(i, mask)) {
 145                                 cur = kzalloc_node(len, GFP_KERNEL,
 146                                                    cpu_to_node(i));
 147                                 if (!cur) {
 148                                         /* not unwinding previous changes */
 149                                         ret = -ENOMEM;
 150                                         goto write_unlock;
 151                                 }
 152                                 cur->num_buckets = netdev_flow_limit_table_len;
 153                                 rcu_assign_pointer(sd->flow_limit, cur);
 154                         }
 155                 }
 156 write_unlock:
 157                 mutex_unlock(&flow_limit_update_mutex);
 158         } else {
 159                 char kbuf[128];
 160
 161                 if (*ppos || !*lenp) {
 162                         *lenp = 0;
 163                         goto done;
 164                 }
 165
 166                 cpumask_clear(mask);
 167                 rcu_read_lock();
 168                 for_each_possible_cpu(i) {
 169                         sd = &per_cpu(softnet_data, i);
 170                         if (rcu_dereference(sd->flow_limit))
 171                                 cpumask_set_cpu(i, mask);
 172                 }
 173                 rcu_read_unlock();
 174
 175                 len = min(sizeof(kbuf) - 1, *lenp);
 176                 len = scnprintf(kbuf, len, "%*pb", cpumask_pr_args(mask));
 177                 if (!len) {
 178                         *lenp = 0;
 179                         goto done;
 180                 }
 181                 if (len < *lenp)
 182                         kbuf[len++] = '\n';
 183                 if (copy_to_user(buffer, kbuf, len)) {
 184                         ret = -EFAULT;
 185                         goto done;
 186                 }
 187                 *lenp = len;
 188                 *ppos += len;
 189         }
 190
 191 done:
 192         free_cpumask_var(mask);
 193         return ret;
 194 }
 195
 196 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
 197                                        void __user *buffer, size_t *lenp,
 198                                        loff_t *ppos)
 199 {
 200         unsigned int old, *ptr;
 201         int ret;
 202
 203         mutex_lock(&flow_limit_update_mutex);
 204
 205         ptr = table->data;
 206         old = *ptr;
 207         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 208         if (!ret && write && !is_power_of_2(*ptr)) {
 209                 *ptr = old;
 210                 ret = -EINVAL;
 211         }
 212
 213         mutex_unlock(&flow_limit_update_mutex);
 214         return ret;
 215 }
 216 #endif /* CONFIG_NET_FLOW_LIMIT */
 217
 218 #ifdef CONFIG_NET_SCHED
 219 static int set_default_qdisc(struct ctl_table *table, int write,
 220                              void __user *buffer, size_t *lenp, loff_t *ppos)
 221 {
 222         char id[IFNAMSIZ];
 223         struct ctl_table tbl = {
 224                 .data = id,
 225                 .maxlen = IFNAMSIZ,
 226         };
 227         int ret;
 228
 229         qdisc_get_default(id, IFNAMSIZ);
 230
 231         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 232         if (write && ret == 0)
 233                 ret = qdisc_set_default(id);
 234         return ret;
 235 }
 236 #endif
 237
 238 static int proc_do_dev_weight(struct ctl_table *table, int write,
 239                            void __user *buffer, size_t *lenp, loff_t *ppos)
 240 {
 241         int ret;
 242
 243         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 244         if (ret != 0)
 245                 return ret;
 246
 247         dev_rx_weight = weight_p * dev_weight_rx_bias;
 248         dev_tx_weight = weight_p * dev_weight_tx_bias;
 249
 250         return ret;
 251 }
 252
 253 static int proc_do_rss_key(struct ctl_table *table, int write,
 254                            void __user *buffer, size_t *lenp, loff_t *ppos)
 255 {
 256         struct ctl_table fake_table;
 257         char buf[NETDEV_RSS_KEY_LEN * 3];
 258
 259         snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
 260         fake_table.data = buf;
 261         fake_table.maxlen = sizeof(buf);
 262         return proc_dostring(&fake_table, write, buffer, lenp, ppos);
 263 }
 264
 265 #ifdef CONFIG_BPF_JIT
 266 static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
 267                                            void __user *buffer, size_t *lenp,
 268                                            loff_t *ppos)
 269 {
 270         int ret, jit_enable = *(int *)table->data;
 271         struct ctl_table tmp = *table;
 272
 273         if (write && !capable(CAP_SYS_ADMIN))
 274                 return -EPERM;
 275
 276         tmp.data = &jit_enable;
 277         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
 278         if (write && !ret) {
 279                 if (jit_enable < 2 ||
 280                     (jit_enable == 2 && bpf_dump_raw_ok())) {
 281                         *(int *)table->data = jit_enable;
 282                         if (jit_enable == 2)
 283                                 pr_warn("bpf_jit_enable = 2 was set! NEVER use this in production, only for JIT debugging!\n");
 284                 } else {
 285                         ret = -EPERM;
 286                 }
 287         }
 288         return ret;
 289 }
 290
 291 static int
 292 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 293                                     void __user *buffer, size_t *lenp,
 294                                     loff_t *ppos)
 295 {
 296         if (!capable(CAP_SYS_ADMIN))
 297                 return -EPERM;
 298
 299         return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 300 }
 301
 302 static int
 303 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 304                                      void __user *buffer, size_t *lenp,
 305                                      loff_t *ppos)
 306 {
 307         if (!capable(CAP_SYS_ADMIN))
 308                 return -EPERM;
 309
 310         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 311 }
 312 #endif
 313
 314 static struct ctl_table net_core_table[] = {
 315 #ifdef CONFIG_NET
 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         = &long_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 #endif /* CONFIG_NET */
 514         {
 515                 .procname       = "netdev_budget",
 516                 .data           = &netdev_budget,
 517                 .maxlen         = sizeof(int),
 518                 .mode           = 0644,
 519                 .proc_handler   = proc_dointvec
 520         },
 521         {
 522                 .procname       = "warnings",
 523                 .data           = &net_msg_warn,
 524                 .maxlen         = sizeof(int),
 525                 .mode           = 0644,
 526                 .proc_handler   = proc_dointvec
 527         },
 528         {
 529                 .procname       = "max_skb_frags",
 530                 .data           = &sysctl_max_skb_frags,
 531                 .maxlen         = sizeof(int),
 532                 .mode           = 0644,
 533                 .proc_handler   = proc_dointvec_minmax,
 534                 .extra1         = SYSCTL_ONE,
 535                 .extra2         = &max_skb_frags,
 536         },
 537         {
 538                 .procname       = "netdev_budget_usecs",
 539                 .data           = &netdev_budget_usecs,
 540                 .maxlen         = sizeof(unsigned int),
 541                 .mode           = 0644,
 542                 .proc_handler   = proc_dointvec_minmax,
 543                 .extra1         = SYSCTL_ZERO,
 544         },
 545         {
 546                 .procname       = "fb_tunnels_only_for_init_net",
 547                 .data           = &sysctl_fb_tunnels_only_for_init_net,
 548                 .maxlen         = sizeof(int),
 549                 .mode           = 0644,
 550                 .proc_handler   = proc_dointvec_minmax,
 551                 .extra1         = SYSCTL_ZERO,
 552                 .extra2         = SYSCTL_ONE,
 553         },
 554         {
 555                 .procname       = "devconf_inherit_init_net",
 556                 .data           = &sysctl_devconf_inherit_init_net,
 557                 .maxlen         = sizeof(int),
 558                 .mode           = 0644,
 559                 .proc_handler   = proc_dointvec_minmax,
 560                 .extra1         = SYSCTL_ZERO,
 561                 .extra2         = &two,
 562         },
 563         {
 564                 .procname       = "high_order_alloc_disable",
 565                 .data           = &net_high_order_alloc_disable_key.key,
 566                 .maxlen         = sizeof(net_high_order_alloc_disable_key),
 567                 .mode           = 0644,
 568                 .proc_handler   = proc_do_static_key,
 569         },
 570         { }
 571 };
 572
 573 static struct ctl_table netns_core_table[] = {
 574         {
 575                 .procname       = "somaxconn",
 576                 .data           = &init_net.core.sysctl_somaxconn,
 577                 .maxlen         = sizeof(int),
 578                 .mode           = 0644,
 579                 .extra1         = SYSCTL_ZERO,
 580                 .proc_handler   = proc_dointvec_minmax
 581         },
 582         { }
 583 };
 584
 585 static __net_init int sysctl_core_net_init(struct net *net)
 586 {
 587         struct ctl_table *tbl;
 588
 589         tbl = netns_core_table;
 590         if (!net_eq(net, &init_net)) {
 591                 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
 592                 if (tbl == NULL)
 593                         goto err_dup;
 594
 595                 tbl[0].data = &net->core.sysctl_somaxconn;
 596
 597                 /* Don't export any sysctls to unprivileged users */
 598                 if (net->user_ns != &init_user_ns) {
 599                         tbl[0].procname = NULL;
 600                 }
 601         }
 602
 603         net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
 604         if (net->core.sysctl_hdr == NULL)
 605                 goto err_reg;
 606
 607         return 0;
 608
 609 err_reg:
 610         if (tbl != netns_core_table)
 611                 kfree(tbl);
 612 err_dup:
 613         return -ENOMEM;
 614 }
 615
 616 static __net_exit void sysctl_core_net_exit(struct net *net)
 617 {
 618         struct ctl_table *tbl;
 619
 620         tbl = net->core.sysctl_hdr->ctl_table_arg;
 621         unregister_net_sysctl_table(net->core.sysctl_hdr);
 622         BUG_ON(tbl == netns_core_table);
 623         kfree(tbl);
 624 }
 625
 626 static __net_initdata struct pernet_operations sysctl_core_ops = {
 627         .init = sysctl_core_net_init,
 628         .exit = sysctl_core_net_exit,
 629 };
 630
 631 static __init int sysctl_core_init(void)
 632 {
 633         register_net_sysctl(&init_net, "net/core", net_core_table);
 634         return register_pernet_subsys(&sysctl_core_ops);
 635 }
 636
 637 fs_initcall(sysctl_core_init);