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