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 /* 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  */
  45 int sysctl_devconf_inherit_init_net __read_mostly;
  46 EXPORT_SYMBOL(sysctl_devconf_inherit_init_net);
  47
  48 #ifdef CONFIG_RPS
  49 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
  50                                 void __user *buffer, size_t *lenp, loff_t *ppos)
  51 {
  52         unsigned int orig_size, size;
  53         int ret, i;
  54         struct ctl_table tmp = {
  55                 .data = &size,
  56                 .maxlen = sizeof(size),
  57                 .mode = table->mode
  58         };
  59         struct rps_sock_flow_table *orig_sock_table, *sock_table;
  60         static DEFINE_MUTEX(sock_flow_mutex);
  61
  62         mutex_lock(&sock_flow_mutex);
  63
  64         orig_sock_table = rcu_dereference_protected(rps_sock_flow_table,
  65                                         lockdep_is_held(&sock_flow_mutex));
  66         size = orig_size = orig_sock_table ? orig_sock_table->mask + 1 : 0;
  67
  68         ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);
  69
  70         if (write) {
  71                 if (size) {
  72                         if (size > 1<<29) {
  73                                 /* Enforce limit to prevent overflow */
  74                                 mutex_unlock(&sock_flow_mutex);
  75                                 return -EINVAL;
  76                         }
  77                         size = roundup_pow_of_two(size);
  78                         if (size != orig_size) {
  79                                 sock_table =
  80                                     vmalloc(RPS_SOCK_FLOW_TABLE_SIZE(size));
  81                                 if (!sock_table) {
  82                                         mutex_unlock(&sock_flow_mutex);
  83                                         return -ENOMEM;
  84                                 }
  85                                 rps_cpu_mask = roundup_pow_of_two(nr_cpu_ids) - 1;
  86                                 sock_table->mask = size - 1;
  87                         } else
  88                                 sock_table = orig_sock_table;
  89
  90                         for (i = 0; i < size; i++)
  91                                 sock_table->ents[i] = RPS_NO_CPU;
  92                 } else
  93                         sock_table = NULL;
  94
  95                 if (sock_table != orig_sock_table) {
  96                         rcu_assign_pointer(rps_sock_flow_table, sock_table);
  97                         if (sock_table) {
  98                                 static_branch_inc(&rps_needed);
  99                                 static_branch_inc(&rfs_needed);
 100                         }
 101                         if (orig_sock_table) {
 102                                 static_branch_dec(&rps_needed);
 103                                 static_branch_dec(&rfs_needed);
 104                                 synchronize_rcu();
 105                                 vfree(orig_sock_table);
 106                         }
 107                 }
 108         }
 109
 110         mutex_unlock(&sock_flow_mutex);
 111
 112         return ret;
 113 }
 114 #endif /* CONFIG_RPS */
 115
 116 #ifdef CONFIG_NET_FLOW_LIMIT
 117 static DEFINE_MUTEX(flow_limit_update_mutex);
 118
 119 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
 120                                  void __user *buffer, size_t *lenp,
 121                                  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_user(buffer, *lenp, 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                 if (copy_to_user(buffer, kbuf, len)) {
 186                         ret = -EFAULT;
 187                         goto done;
 188                 }
 189                 *lenp = len;
 190                 *ppos += len;
 191         }
 192
 193 done:
 194         free_cpumask_var(mask);
 195         return ret;
 196 }
 197
 198 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
 199                                        void __user *buffer, size_t *lenp,
 200                                        loff_t *ppos)
 201 {
 202         unsigned int old, *ptr;
 203         int ret;
 204
 205         mutex_lock(&flow_limit_update_mutex);
 206
 207         ptr = table->data;
 208         old = *ptr;
 209         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 210         if (!ret && write && !is_power_of_2(*ptr)) {
 211                 *ptr = old;
 212                 ret = -EINVAL;
 213         }
 214
 215         mutex_unlock(&flow_limit_update_mutex);
 216         return ret;
 217 }
 218 #endif /* CONFIG_NET_FLOW_LIMIT */
 219
 220 #ifdef CONFIG_NET_SCHED
 221 static int set_default_qdisc(struct ctl_table *table, int write,
 222                              void __user *buffer, size_t *lenp, loff_t *ppos)
 223 {
 224         char id[IFNAMSIZ];
 225         struct ctl_table tbl = {
 226                 .data = id,
 227                 .maxlen = IFNAMSIZ,
 228         };
 229         int ret;
 230
 231         qdisc_get_default(id, IFNAMSIZ);
 232
 233         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 234         if (write && ret == 0)
 235                 ret = qdisc_set_default(id);
 236         return ret;
 237 }
 238 #endif
 239
 240 static int proc_do_dev_weight(struct ctl_table *table, int write,
 241                            void __user *buffer, size_t *lenp, loff_t *ppos)
 242 {
 243         int ret;
 244
 245         ret = proc_dointvec(table, write, buffer, lenp, ppos);
 246         if (ret != 0)
 247                 return ret;
 248
 249         dev_rx_weight = weight_p * dev_weight_rx_bias;
 250         dev_tx_weight = weight_p * dev_weight_tx_bias;
 251
 252         return ret;
 253 }
 254
 255 static int proc_do_rss_key(struct ctl_table *table, int write,
 256                            void __user *buffer, size_t *lenp, loff_t *ppos)
 257 {
 258         struct ctl_table fake_table;
 259         char buf[NETDEV_RSS_KEY_LEN * 3];
 260
 261         snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
 262         fake_table.data = buf;
 263         fake_table.maxlen = sizeof(buf);
 264         return proc_dostring(&fake_table, write, buffer, lenp, ppos);
 265 }
 266
 267 #ifdef CONFIG_BPF_JIT
 268 static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
 269                                            void __user *buffer, size_t *lenp,
 270                                            loff_t *ppos)
 271 {
 272         int ret, jit_enable = *(int *)table->data;
 273         struct ctl_table tmp = *table;
 274
 275         if (write && !capable(CAP_SYS_ADMIN))
 276                 return -EPERM;
 277
 278         tmp.data = &jit_enable;
 279         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
 280         if (write && !ret) {
 281                 if (jit_enable < 2 ||
 282                     (jit_enable == 2 && bpf_dump_raw_ok())) {
 283                         *(int *)table->data = jit_enable;
 284                         if (jit_enable == 2)
 285                                 pr_warn("bpf_jit_enable = 2 was set! NEVER use this in production, only for JIT debugging!\n");
 286                 } else {
 287                         ret = -EPERM;
 288                 }
 289         }
 290         return ret;
 291 }
 292
 293 static int
 294 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 295                                     void __user *buffer, size_t *lenp,
 296                                     loff_t *ppos)
 297 {
 298         if (!capable(CAP_SYS_ADMIN))
 299                 return -EPERM;
 300
 301         return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 302 }
 303
 304 static int
 305 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
 306                                      void __user *buffer, size_t *lenp,
 307                                      loff_t *ppos)
 308 {
 309         if (!capable(CAP_SYS_ADMIN))
 310                 return -EPERM;
 311
 312         return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 313 }
 314 #endif
 315
 316 static struct ctl_table net_core_table[] = {
 317 #ifdef CONFIG_NET
 318         {
 319                 .procname       = "wmem_max",
 320                 .data           = &sysctl_wmem_max,
 321                 .maxlen         = sizeof(int),
 322                 .mode           = 0644,
 323                 .proc_handler   = proc_dointvec_minmax,
 324                 .extra1         = &min_sndbuf,
 325         },
 326         {
 327                 .procname       = "rmem_max",
 328                 .data           = &sysctl_rmem_max,
 329                 .maxlen         = sizeof(int),
 330                 .mode           = 0644,
 331                 .proc_handler   = proc_dointvec_minmax,
 332                 .extra1         = &min_rcvbuf,
 333         },
 334         {
 335                 .procname       = "wmem_default",
 336                 .data           = &sysctl_wmem_default,
 337                 .maxlen         = sizeof(int),
 338                 .mode           = 0644,
 339                 .proc_handler   = proc_dointvec_minmax,
 340                 .extra1         = &min_sndbuf,
 341         },
 342         {
 343                 .procname       = "rmem_default",
 344                 .data           = &sysctl_rmem_default,
 345                 .maxlen         = sizeof(int),
 346                 .mode           = 0644,
 347                 .proc_handler   = proc_dointvec_minmax,
 348                 .extra1         = &min_rcvbuf,
 349         },
 350         {
 351                 .procname       = "dev_weight",
 352                 .data           = &weight_p,
 353                 .maxlen         = sizeof(int),
 354                 .mode           = 0644,
 355                 .proc_handler   = proc_do_dev_weight,
 356         },
 357         {
 358                 .procname       = "dev_weight_rx_bias",
 359                 .data           = &dev_weight_rx_bias,
 360                 .maxlen         = sizeof(int),
 361                 .mode           = 0644,
 362                 .proc_handler   = proc_do_dev_weight,
 363         },
 364         {
 365                 .procname       = "dev_weight_tx_bias",
 366                 .data           = &dev_weight_tx_bias,
 367                 .maxlen         = sizeof(int),
 368                 .mode           = 0644,
 369                 .proc_handler   = proc_do_dev_weight,
 370         },
 371         {
 372                 .procname       = "netdev_max_backlog",
 373                 .data           = &netdev_max_backlog,
 374                 .maxlen         = sizeof(int),
 375                 .mode           = 0644,
 376                 .proc_handler   = proc_dointvec
 377         },
 378         {
 379                 .procname       = "netdev_rss_key",
 380                 .data           = &netdev_rss_key,
 381                 .maxlen         = sizeof(int),
 382                 .mode           = 0444,
 383                 .proc_handler   = proc_do_rss_key,
 384         },
 385 #ifdef CONFIG_BPF_JIT
 386         {
 387                 .procname       = "bpf_jit_enable",
 388                 .data           = &bpf_jit_enable,
 389                 .maxlen         = sizeof(int),
 390                 .mode           = 0644,
 391                 .proc_handler   = proc_dointvec_minmax_bpf_enable,
 392 # ifdef CONFIG_BPF_JIT_ALWAYS_ON
 393                 .extra1         = &one,
 394                 .extra2         = &one,
 395 # else
 396                 .extra1         = &zero,
 397                 .extra2         = &two,
 398 # endif
 399         },
 400 # ifdef CONFIG_HAVE_EBPF_JIT
 401         {
 402                 .procname       = "bpf_jit_harden",
 403                 .data           = &bpf_jit_harden,
 404                 .maxlen         = sizeof(int),
 405                 .mode           = 0600,
 406                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
 407                 .extra1         = &zero,
 408                 .extra2         = &two,
 409         },
 410         {
 411                 .procname       = "bpf_jit_kallsyms",
 412                 .data           = &bpf_jit_kallsyms,
 413                 .maxlen         = sizeof(int),
 414                 .mode           = 0600,
 415                 .proc_handler   = proc_dointvec_minmax_bpf_restricted,
 416                 .extra1         = &zero,
 417                 .extra2         = &one,
 418         },
 419 # endif
 420         {
 421                 .procname       = "bpf_jit_limit",
 422                 .data           = &bpf_jit_limit,
 423                 .maxlen         = sizeof(long),
 424                 .mode           = 0600,
 425                 .proc_handler   = proc_dolongvec_minmax_bpf_restricted,
 426                 .extra1         = &long_one,
 427                 .extra2         = &long_max,
 428         },
 429 #endif
 430         {
 431                 .procname       = "netdev_tstamp_prequeue",
 432                 .data           = &netdev_tstamp_prequeue,
 433                 .maxlen         = sizeof(int),
 434                 .mode           = 0644,
 435                 .proc_handler   = proc_dointvec
 436         },
 437         {
 438                 .procname       = "message_cost",
 439                 .data           = &net_ratelimit_state.interval,
 440                 .maxlen         = sizeof(int),
 441                 .mode           = 0644,
 442                 .proc_handler   = proc_dointvec_jiffies,
 443         },
 444         {
 445                 .procname       = "message_burst",
 446                 .data           = &net_ratelimit_state.burst,
 447                 .maxlen         = sizeof(int),
 448                 .mode           = 0644,
 449                 .proc_handler   = proc_dointvec,
 450         },
 451         {
 452                 .procname       = "optmem_max",
 453                 .data           = &sysctl_optmem_max,
 454                 .maxlen         = sizeof(int),
 455                 .mode           = 0644,
 456                 .proc_handler   = proc_dointvec
 457         },
 458         {
 459                 .procname       = "tstamp_allow_data",
 460                 .data           = &sysctl_tstamp_allow_data,
 461                 .maxlen         = sizeof(int),
 462                 .mode           = 0644,
 463                 .proc_handler   = proc_dointvec_minmax,
 464                 .extra1         = &zero,
 465                 .extra2         = &one
 466         },
 467 #ifdef CONFIG_RPS
 468         {
 469                 .procname       = "rps_sock_flow_entries",
 470                 .maxlen         = sizeof(int),
 471                 .mode           = 0644,
 472                 .proc_handler   = rps_sock_flow_sysctl
 473         },
 474 #endif
 475 #ifdef CONFIG_NET_FLOW_LIMIT
 476         {
 477                 .procname       = "flow_limit_cpu_bitmap",
 478                 .mode           = 0644,
 479                 .proc_handler   = flow_limit_cpu_sysctl
 480         },
 481         {
 482                 .procname       = "flow_limit_table_len",
 483                 .data           = &netdev_flow_limit_table_len,
 484                 .maxlen         = sizeof(int),
 485                 .mode           = 0644,
 486                 .proc_handler   = flow_limit_table_len_sysctl
 487         },
 488 #endif /* CONFIG_NET_FLOW_LIMIT */
 489 #ifdef CONFIG_NET_RX_BUSY_POLL
 490         {
 491                 .procname       = "busy_poll",
 492                 .data           = &sysctl_net_busy_poll,
 493                 .maxlen         = sizeof(unsigned int),
 494                 .mode           = 0644,
 495                 .proc_handler   = proc_dointvec_minmax,
 496                 .extra1         = &zero,
 497         },
 498         {
 499                 .procname       = "busy_read",
 500                 .data           = &sysctl_net_busy_read,
 501                 .maxlen         = sizeof(unsigned int),
 502                 .mode           = 0644,
 503                 .proc_handler   = proc_dointvec_minmax,
 504                 .extra1         = &zero,
 505         },
 506 #endif
 507 #ifdef CONFIG_NET_SCHED
 508         {
 509                 .procname       = "default_qdisc",
 510                 .mode           = 0644,
 511                 .maxlen         = IFNAMSIZ,
 512                 .proc_handler   = set_default_qdisc
 513         },
 514 #endif
 515 #endif /* CONFIG_NET */
 516         {
 517                 .procname       = "netdev_budget",
 518                 .data           = &netdev_budget,
 519                 .maxlen         = sizeof(int),
 520                 .mode           = 0644,
 521                 .proc_handler   = proc_dointvec
 522         },
 523         {
 524                 .procname       = "warnings",
 525                 .data           = &net_msg_warn,
 526                 .maxlen         = sizeof(int),
 527                 .mode           = 0644,
 528                 .proc_handler   = proc_dointvec
 529         },
 530         {
 531                 .procname       = "max_skb_frags",
 532                 .data           = &sysctl_max_skb_frags,
 533                 .maxlen         = sizeof(int),
 534                 .mode           = 0644,
 535                 .proc_handler   = proc_dointvec_minmax,
 536                 .extra1         = &one,
 537                 .extra2         = &max_skb_frags,
 538         },
 539         {
 540                 .procname       = "netdev_budget_usecs",
 541                 .data           = &netdev_budget_usecs,
 542                 .maxlen         = sizeof(unsigned int),
 543                 .mode           = 0644,
 544                 .proc_handler   = proc_dointvec_minmax,
 545                 .extra1         = &zero,
 546         },
 547         {
 548                 .procname       = "fb_tunnels_only_for_init_net",
 549                 .data           = &sysctl_fb_tunnels_only_for_init_net,
 550                 .maxlen         = sizeof(int),
 551                 .mode           = 0644,
 552                 .proc_handler   = proc_dointvec_minmax,
 553                 .extra1         = &zero,
 554                 .extra2         = &one,
 555         },
 556         {
 557                 .procname       = "devconf_inherit_init_net",
 558                 .data           = &sysctl_devconf_inherit_init_net,
 559                 .maxlen         = sizeof(int),
 560                 .mode           = 0644,
 561                 .proc_handler   = proc_dointvec_minmax,
 562                 .extra1         = &zero,
 563                 .extra2         = &two,
 564         },
 565         {
 566                 .procname       = "high_order_alloc_disable",
 567                 .data           = &net_high_order_alloc_disable_key.key,
 568                 .maxlen         = sizeof(net_high_order_alloc_disable_key),
 569                 .mode           = 0644,
 570                 .proc_handler   = proc_do_static_key,
 571         },
 572         { }
 573 };
 574
 575 static struct ctl_table netns_core_table[] = {
 576         {
 577                 .procname       = "somaxconn",
 578                 .data           = &init_net.core.sysctl_somaxconn,
 579                 .maxlen         = sizeof(int),
 580                 .mode           = 0644,
 581                 .extra1         = &zero,
 582                 .proc_handler   = proc_dointvec_minmax
 583         },
 584         { }
 585 };
 586
 587 static __net_init int sysctl_core_net_init(struct net *net)
 588 {
 589         struct ctl_table *tbl;
 590
 591         tbl = netns_core_table;
 592         if (!net_eq(net, &init_net)) {
 593                 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
 594                 if (tbl == NULL)
 595                         goto err_dup;
 596
 597                 tbl[0].data = &net->core.sysctl_somaxconn;
 598
 599                 /* Don't export any sysctls to unprivileged users */
 600                 if (net->user_ns != &init_user_ns) {
 601                         tbl[0].procname = NULL;
 602                 }
 603         }
 604
 605         net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
 606         if (net->core.sysctl_hdr == NULL)
 607                 goto err_reg;
 608
 609         return 0;
 610
 611 err_reg:
 612         if (tbl != netns_core_table)
 613                 kfree(tbl);
 614 err_dup:
 615         return -ENOMEM;
 616 }
 617
 618 static __net_exit void sysctl_core_net_exit(struct net *net)
 619 {
 620         struct ctl_table *tbl;
 621
 622         tbl = net->core.sysctl_hdr->ctl_table_arg;
 623         unregister_net_sysctl_table(net->core.sysctl_hdr);
 624         BUG_ON(tbl == netns_core_table);
 625         kfree(tbl);
 626 }
 627
 628 static __net_initdata struct pernet_operations sysctl_core_ops = {
 629         .init = sysctl_core_net_init,
 630         .exit = sysctl_core_net_exit,
 631 };
 632
 633 static __init int sysctl_core_init(void)
 634 {
 635         register_net_sysctl(&init_net, "net/core", net_core_table);
 636         return register_pernet_subsys(&sysctl_core_ops);
 637 }
 638
 639 fs_initcall(sysctl_core_init);