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
rps_sock_flow_sysctl(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)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
flow_limit_cpu_sysctl(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)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
flow_limit_table_len_sysctl(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)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
set_default_qdisc(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)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
proc_do_dev_weight(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)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
proc_do_rss_key(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)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
proc_dointvec_minmax_bpf_enable(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)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
proc_dointvec_minmax_bpf_restricted(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)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
proc_dolongvec_minmax_bpf_restricted(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)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 .procname = "gro_normal_batch",
572 .data = &gro_normal_batch,
573 .maxlen = sizeof(unsigned int),
574 .mode = 0644,
575 .proc_handler = proc_dointvec_minmax,
576 .extra1 = SYSCTL_ONE,
577 },
578 { }
579 };
580
581 static struct ctl_table netns_core_table[] = {
582 {
583 .procname = "somaxconn",
584 .data = &init_net.core.sysctl_somaxconn,
585 .maxlen = sizeof(int),
586 .mode = 0644,
587 .extra1 = SYSCTL_ZERO,
588 .proc_handler = proc_dointvec_minmax
589 },
590 { }
591 };
592
sysctl_core_net_init(struct net * net)593 static __net_init int sysctl_core_net_init(struct net *net)
594 {
595 struct ctl_table *tbl;
596
597 tbl = netns_core_table;
598 if (!net_eq(net, &init_net)) {
599 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
600 if (tbl == NULL)
601 goto err_dup;
602
603 tbl[0].data = &net->core.sysctl_somaxconn;
604
605 /* Don't export any sysctls to unprivileged users */
606 if (net->user_ns != &init_user_ns) {
607 tbl[0].procname = NULL;
608 }
609 }
610
611 net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
612 if (net->core.sysctl_hdr == NULL)
613 goto err_reg;
614
615 return 0;
616
617 err_reg:
618 if (tbl != netns_core_table)
619 kfree(tbl);
620 err_dup:
621 return -ENOMEM;
622 }
623
sysctl_core_net_exit(struct net * net)624 static __net_exit void sysctl_core_net_exit(struct net *net)
625 {
626 struct ctl_table *tbl;
627
628 tbl = net->core.sysctl_hdr->ctl_table_arg;
629 unregister_net_sysctl_table(net->core.sysctl_hdr);
630 BUG_ON(tbl == netns_core_table);
631 kfree(tbl);
632 }
633
634 static __net_initdata struct pernet_operations sysctl_core_ops = {
635 .init = sysctl_core_net_init,
636 .exit = sysctl_core_net_exit,
637 };
638
sysctl_core_init(void)639 static __init int sysctl_core_init(void)
640 {
641 register_net_sysctl(&init_net, "net/core", net_core_table);
642 return register_pernet_subsys(&sysctl_core_ops);
643 }
644
645 fs_initcall(sysctl_core_init);
646
