1 // SPDX-License-Identifier: GPL-2.0
2 /* -*- linux-c -*-
3 * sysctl_net_core.c: sysctl interface to net core subsystem.
4 *
5 * Begun April 1, 1996, Mike Shaver.
6 * Added /proc/sys/net/core directory entry (empty =) ). [MS]
7 */
8
9 #include <linux/mm.h>
10 #include <linux/sysctl.h>
11 #include <linux/module.h>
12 #include <linux/socket.h>
13 #include <linux/netdevice.h>
14 #include <linux/ratelimit.h>
15 #include <linux/vmalloc.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18
19 #include <net/ip.h>
20 #include <net/sock.h>
21 #include <net/net_ratelimit.h>
22 #include <net/busy_poll.h>
23 #include <net/pkt_sched.h>
24
25 static int two = 2;
26 static int three = 3;
27 static int min_sndbuf = SOCK_MIN_SNDBUF;
28 static int min_rcvbuf = SOCK_MIN_RCVBUF;
29 static int max_skb_frags = MAX_SKB_FRAGS;
30 static long long_one __maybe_unused = 1;
31 static long long_max __maybe_unused = LONG_MAX;
32
33 static int net_msg_warn; /* Unused, but still a sysctl */
34
35 int sysctl_fb_tunnels_only_for_init_net __read_mostly = 0;
36 EXPORT_SYMBOL(sysctl_fb_tunnels_only_for_init_net);
37
38 /* 0 - Keep current behavior:
39 * IPv4: inherit all current settings from init_net
40 * IPv6: reset all settings to default
41 * 1 - Both inherit all current settings from init_net
42 * 2 - Both reset all settings to default
43 * 3 - Both inherit all settings from current netns
44 */
45 int sysctl_devconf_inherit_init_net __read_mostly;
46 EXPORT_SYMBOL(sysctl_devconf_inherit_init_net);
47
48 #ifdef CONFIG_RPS
rps_sock_flow_sysctl(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)49 static int rps_sock_flow_sysctl(struct ctl_table *table, int write,
50 void *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
flow_limit_cpu_sysctl(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)119 static int flow_limit_cpu_sysctl(struct ctl_table *table, int write,
120 void *buffer, size_t *lenp, loff_t *ppos)
121 {
122 struct sd_flow_limit *cur;
123 struct softnet_data *sd;
124 cpumask_var_t mask;
125 int i, len, ret = 0;
126
127 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
128 return -ENOMEM;
129
130 if (write) {
131 ret = cpumask_parse(buffer, mask);
132 if (ret)
133 goto done;
134
135 mutex_lock(&flow_limit_update_mutex);
136 len = sizeof(*cur) + netdev_flow_limit_table_len;
137 for_each_possible_cpu(i) {
138 sd = &per_cpu(softnet_data, i);
139 cur = rcu_dereference_protected(sd->flow_limit,
140 lockdep_is_held(&flow_limit_update_mutex));
141 if (cur && !cpumask_test_cpu(i, mask)) {
142 RCU_INIT_POINTER(sd->flow_limit, NULL);
143 synchronize_rcu();
144 kfree(cur);
145 } else if (!cur && cpumask_test_cpu(i, mask)) {
146 cur = kzalloc_node(len, GFP_KERNEL,
147 cpu_to_node(i));
148 if (!cur) {
149 /* not unwinding previous changes */
150 ret = -ENOMEM;
151 goto write_unlock;
152 }
153 cur->num_buckets = netdev_flow_limit_table_len;
154 rcu_assign_pointer(sd->flow_limit, cur);
155 }
156 }
157 write_unlock:
158 mutex_unlock(&flow_limit_update_mutex);
159 } else {
160 char kbuf[128];
161
162 if (*ppos || !*lenp) {
163 *lenp = 0;
164 goto done;
165 }
166
167 cpumask_clear(mask);
168 rcu_read_lock();
169 for_each_possible_cpu(i) {
170 sd = &per_cpu(softnet_data, i);
171 if (rcu_dereference(sd->flow_limit))
172 cpumask_set_cpu(i, mask);
173 }
174 rcu_read_unlock();
175
176 len = min(sizeof(kbuf) - 1, *lenp);
177 len = scnprintf(kbuf, len, "%*pb", cpumask_pr_args(mask));
178 if (!len) {
179 *lenp = 0;
180 goto done;
181 }
182 if (len < *lenp)
183 kbuf[len++] = '\n';
184 memcpy(buffer, kbuf, len);
185 *lenp = len;
186 *ppos += len;
187 }
188
189 done:
190 free_cpumask_var(mask);
191 return ret;
192 }
193
flow_limit_table_len_sysctl(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)194 static int flow_limit_table_len_sysctl(struct ctl_table *table, int write,
195 void *buffer, size_t *lenp, loff_t *ppos)
196 {
197 unsigned int old, *ptr;
198 int ret;
199
200 mutex_lock(&flow_limit_update_mutex);
201
202 ptr = table->data;
203 old = *ptr;
204 ret = proc_dointvec(table, write, buffer, lenp, ppos);
205 if (!ret && write && !is_power_of_2(*ptr)) {
206 *ptr = old;
207 ret = -EINVAL;
208 }
209
210 mutex_unlock(&flow_limit_update_mutex);
211 return ret;
212 }
213 #endif /* CONFIG_NET_FLOW_LIMIT */
214
215 #ifdef CONFIG_NET_SCHED
set_default_qdisc(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)216 static int set_default_qdisc(struct ctl_table *table, int write,
217 void *buffer, size_t *lenp, loff_t *ppos)
218 {
219 char id[IFNAMSIZ];
220 struct ctl_table tbl = {
221 .data = id,
222 .maxlen = IFNAMSIZ,
223 };
224 int ret;
225
226 qdisc_get_default(id, IFNAMSIZ);
227
228 ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
229 if (write && ret == 0)
230 ret = qdisc_set_default(id);
231 return ret;
232 }
233 #endif
234
proc_do_dev_weight(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)235 static int proc_do_dev_weight(struct ctl_table *table, int write,
236 void *buffer, size_t *lenp, loff_t *ppos)
237 {
238 int ret;
239
240 ret = proc_dointvec(table, write, buffer, lenp, ppos);
241 if (ret != 0)
242 return ret;
243
244 dev_rx_weight = weight_p * dev_weight_rx_bias;
245 dev_tx_weight = weight_p * dev_weight_tx_bias;
246
247 return ret;
248 }
249
proc_do_rss_key(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)250 static int proc_do_rss_key(struct ctl_table *table, int write,
251 void *buffer, size_t *lenp, loff_t *ppos)
252 {
253 struct ctl_table fake_table;
254 char buf[NETDEV_RSS_KEY_LEN * 3];
255
256 snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
257 fake_table.data = buf;
258 fake_table.maxlen = sizeof(buf);
259 return proc_dostring(&fake_table, write, buffer, lenp, ppos);
260 }
261
262 #ifdef CONFIG_BPF_JIT
proc_dointvec_minmax_bpf_enable(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)263 static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write,
264 void *buffer, size_t *lenp,
265 loff_t *ppos)
266 {
267 int ret, jit_enable = *(int *)table->data;
268 struct ctl_table tmp = *table;
269
270 if (write && !capable(CAP_SYS_ADMIN))
271 return -EPERM;
272
273 tmp.data = &jit_enable;
274 ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
275 if (write && !ret) {
276 if (jit_enable < 2 ||
277 (jit_enable == 2 && bpf_dump_raw_ok(current_cred()))) {
278 *(int *)table->data = jit_enable;
279 if (jit_enable == 2)
280 pr_warn("bpf_jit_enable = 2 was set! NEVER use this in production, only for JIT debugging!\n");
281 } else {
282 ret = -EPERM;
283 }
284 }
285 return ret;
286 }
287
288 # ifdef CONFIG_HAVE_EBPF_JIT
289 static int
proc_dointvec_minmax_bpf_restricted(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)290 proc_dointvec_minmax_bpf_restricted(struct ctl_table *table, int write,
291 void *buffer, size_t *lenp, loff_t *ppos)
292 {
293 if (!capable(CAP_SYS_ADMIN))
294 return -EPERM;
295
296 return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
297 }
298 # endif /* CONFIG_HAVE_EBPF_JIT */
299
300 static int
proc_dolongvec_minmax_bpf_restricted(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)301 proc_dolongvec_minmax_bpf_restricted(struct ctl_table *table, int write,
302 void *buffer, size_t *lenp, loff_t *ppos)
303 {
304 if (!capable(CAP_SYS_ADMIN))
305 return -EPERM;
306
307 return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
308 }
309 #endif
310
311 static struct ctl_table net_core_table[] = {
312 #ifdef CONFIG_NET
313 {
314 .procname = "wmem_max",
315 .data = &sysctl_wmem_max,
316 .maxlen = sizeof(int),
317 .mode = 0644,
318 .proc_handler = proc_dointvec_minmax,
319 .extra1 = &min_sndbuf,
320 },
321 {
322 .procname = "rmem_max",
323 .data = &sysctl_rmem_max,
324 .maxlen = sizeof(int),
325 .mode = 0644,
326 .proc_handler = proc_dointvec_minmax,
327 .extra1 = &min_rcvbuf,
328 },
329 {
330 .procname = "wmem_default",
331 .data = &sysctl_wmem_default,
332 .maxlen = sizeof(int),
333 .mode = 0644,
334 .proc_handler = proc_dointvec_minmax,
335 .extra1 = &min_sndbuf,
336 },
337 {
338 .procname = "rmem_default",
339 .data = &sysctl_rmem_default,
340 .maxlen = sizeof(int),
341 .mode = 0644,
342 .proc_handler = proc_dointvec_minmax,
343 .extra1 = &min_rcvbuf,
344 },
345 {
346 .procname = "dev_weight",
347 .data = &weight_p,
348 .maxlen = sizeof(int),
349 .mode = 0644,
350 .proc_handler = proc_do_dev_weight,
351 },
352 {
353 .procname = "dev_weight_rx_bias",
354 .data = &dev_weight_rx_bias,
355 .maxlen = sizeof(int),
356 .mode = 0644,
357 .proc_handler = proc_do_dev_weight,
358 },
359 {
360 .procname = "dev_weight_tx_bias",
361 .data = &dev_weight_tx_bias,
362 .maxlen = sizeof(int),
363 .mode = 0644,
364 .proc_handler = proc_do_dev_weight,
365 },
366 {
367 .procname = "netdev_max_backlog",
368 .data = &netdev_max_backlog,
369 .maxlen = sizeof(int),
370 .mode = 0644,
371 .proc_handler = proc_dointvec
372 },
373 {
374 .procname = "netdev_rss_key",
375 .data = &netdev_rss_key,
376 .maxlen = sizeof(int),
377 .mode = 0444,
378 .proc_handler = proc_do_rss_key,
379 },
380 #ifdef CONFIG_BPF_JIT
381 {
382 .procname = "bpf_jit_enable",
383 .data = &bpf_jit_enable,
384 .maxlen = sizeof(int),
385 .mode = 0644,
386 .proc_handler = proc_dointvec_minmax_bpf_enable,
387 # ifdef CONFIG_BPF_JIT_ALWAYS_ON
388 .extra1 = SYSCTL_ONE,
389 .extra2 = SYSCTL_ONE,
390 # else
391 .extra1 = SYSCTL_ZERO,
392 .extra2 = &two,
393 # endif
394 },
395 # ifdef CONFIG_HAVE_EBPF_JIT
396 {
397 .procname = "bpf_jit_harden",
398 .data = &bpf_jit_harden,
399 .maxlen = sizeof(int),
400 .mode = 0600,
401 .proc_handler = proc_dointvec_minmax_bpf_restricted,
402 .extra1 = SYSCTL_ZERO,
403 .extra2 = &two,
404 },
405 {
406 .procname = "bpf_jit_kallsyms",
407 .data = &bpf_jit_kallsyms,
408 .maxlen = sizeof(int),
409 .mode = 0600,
410 .proc_handler = proc_dointvec_minmax_bpf_restricted,
411 .extra1 = SYSCTL_ZERO,
412 .extra2 = SYSCTL_ONE,
413 },
414 # endif
415 {
416 .procname = "bpf_jit_limit",
417 .data = &bpf_jit_limit,
418 .maxlen = sizeof(long),
419 .mode = 0600,
420 .proc_handler = proc_dolongvec_minmax_bpf_restricted,
421 .extra1 = &long_one,
422 .extra2 = &long_max,
423 },
424 #endif
425 {
426 .procname = "netdev_tstamp_prequeue",
427 .data = &netdev_tstamp_prequeue,
428 .maxlen = sizeof(int),
429 .mode = 0644,
430 .proc_handler = proc_dointvec
431 },
432 {
433 .procname = "message_cost",
434 .data = &net_ratelimit_state.interval,
435 .maxlen = sizeof(int),
436 .mode = 0644,
437 .proc_handler = proc_dointvec_jiffies,
438 },
439 {
440 .procname = "message_burst",
441 .data = &net_ratelimit_state.burst,
442 .maxlen = sizeof(int),
443 .mode = 0644,
444 .proc_handler = proc_dointvec,
445 },
446 {
447 .procname = "optmem_max",
448 .data = &sysctl_optmem_max,
449 .maxlen = sizeof(int),
450 .mode = 0644,
451 .proc_handler = proc_dointvec
452 },
453 {
454 .procname = "tstamp_allow_data",
455 .data = &sysctl_tstamp_allow_data,
456 .maxlen = sizeof(int),
457 .mode = 0644,
458 .proc_handler = proc_dointvec_minmax,
459 .extra1 = SYSCTL_ZERO,
460 .extra2 = SYSCTL_ONE
461 },
462 #ifdef CONFIG_RPS
463 {
464 .procname = "rps_sock_flow_entries",
465 .maxlen = sizeof(int),
466 .mode = 0644,
467 .proc_handler = rps_sock_flow_sysctl
468 },
469 #endif
470 #ifdef CONFIG_NET_FLOW_LIMIT
471 {
472 .procname = "flow_limit_cpu_bitmap",
473 .mode = 0644,
474 .proc_handler = flow_limit_cpu_sysctl
475 },
476 {
477 .procname = "flow_limit_table_len",
478 .data = &netdev_flow_limit_table_len,
479 .maxlen = sizeof(int),
480 .mode = 0644,
481 .proc_handler = flow_limit_table_len_sysctl
482 },
483 #endif /* CONFIG_NET_FLOW_LIMIT */
484 #ifdef CONFIG_NET_RX_BUSY_POLL
485 {
486 .procname = "busy_poll",
487 .data = &sysctl_net_busy_poll,
488 .maxlen = sizeof(unsigned int),
489 .mode = 0644,
490 .proc_handler = proc_dointvec_minmax,
491 .extra1 = SYSCTL_ZERO,
492 },
493 {
494 .procname = "busy_read",
495 .data = &sysctl_net_busy_read,
496 .maxlen = sizeof(unsigned int),
497 .mode = 0644,
498 .proc_handler = proc_dointvec_minmax,
499 .extra1 = SYSCTL_ZERO,
500 },
501 #endif
502 #ifdef CONFIG_NET_SCHED
503 {
504 .procname = "default_qdisc",
505 .mode = 0644,
506 .maxlen = IFNAMSIZ,
507 .proc_handler = set_default_qdisc
508 },
509 #endif
510 #endif /* CONFIG_NET */
511 {
512 .procname = "netdev_budget",
513 .data = &netdev_budget,
514 .maxlen = sizeof(int),
515 .mode = 0644,
516 .proc_handler = proc_dointvec
517 },
518 {
519 .procname = "warnings",
520 .data = &net_msg_warn,
521 .maxlen = sizeof(int),
522 .mode = 0644,
523 .proc_handler = proc_dointvec
524 },
525 {
526 .procname = "max_skb_frags",
527 .data = &sysctl_max_skb_frags,
528 .maxlen = sizeof(int),
529 .mode = 0644,
530 .proc_handler = proc_dointvec_minmax,
531 .extra1 = SYSCTL_ONE,
532 .extra2 = &max_skb_frags,
533 },
534 {
535 .procname = "netdev_budget_usecs",
536 .data = &netdev_budget_usecs,
537 .maxlen = sizeof(unsigned int),
538 .mode = 0644,
539 .proc_handler = proc_dointvec_minmax,
540 .extra1 = SYSCTL_ZERO,
541 },
542 {
543 .procname = "fb_tunnels_only_for_init_net",
544 .data = &sysctl_fb_tunnels_only_for_init_net,
545 .maxlen = sizeof(int),
546 .mode = 0644,
547 .proc_handler = proc_dointvec_minmax,
548 .extra1 = SYSCTL_ZERO,
549 .extra2 = &two,
550 },
551 {
552 .procname = "devconf_inherit_init_net",
553 .data = &sysctl_devconf_inherit_init_net,
554 .maxlen = sizeof(int),
555 .mode = 0644,
556 .proc_handler = proc_dointvec_minmax,
557 .extra1 = SYSCTL_ZERO,
558 .extra2 = &three,
559 },
560 {
561 .procname = "high_order_alloc_disable",
562 .data = &net_high_order_alloc_disable_key.key,
563 .maxlen = sizeof(net_high_order_alloc_disable_key),
564 .mode = 0644,
565 .proc_handler = proc_do_static_key,
566 },
567 {
568 .procname = "gro_normal_batch",
569 .data = &gro_normal_batch,
570 .maxlen = sizeof(unsigned int),
571 .mode = 0644,
572 .proc_handler = proc_dointvec_minmax,
573 .extra1 = SYSCTL_ONE,
574 },
575 { }
576 };
577
578 static struct ctl_table netns_core_table[] = {
579 {
580 .procname = "somaxconn",
581 .data = &init_net.core.sysctl_somaxconn,
582 .maxlen = sizeof(int),
583 .mode = 0644,
584 .extra1 = SYSCTL_ZERO,
585 .proc_handler = proc_dointvec_minmax
586 },
587 { }
588 };
589
fb_tunnels_only_for_init_net_sysctl_setup(char * str)590 static int __init fb_tunnels_only_for_init_net_sysctl_setup(char *str)
591 {
592 /* fallback tunnels for initns only */
593 if (!strncmp(str, "initns", 6))
594 sysctl_fb_tunnels_only_for_init_net = 1;
595 /* no fallback tunnels anywhere */
596 else if (!strncmp(str, "none", 4))
597 sysctl_fb_tunnels_only_for_init_net = 2;
598
599 return 1;
600 }
601 __setup("fb_tunnels=", fb_tunnels_only_for_init_net_sysctl_setup);
602
sysctl_core_net_init(struct net * net)603 static __net_init int sysctl_core_net_init(struct net *net)
604 {
605 struct ctl_table *tbl;
606
607 tbl = netns_core_table;
608 if (!net_eq(net, &init_net)) {
609 tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
610 if (tbl == NULL)
611 goto err_dup;
612
613 tbl[0].data = &net->core.sysctl_somaxconn;
614
615 /* Don't export any sysctls to unprivileged users */
616 if (net->user_ns != &init_user_ns) {
617 tbl[0].procname = NULL;
618 }
619 }
620
621 net->core.sysctl_hdr = register_net_sysctl(net, "net/core", tbl);
622 if (net->core.sysctl_hdr == NULL)
623 goto err_reg;
624
625 return 0;
626
627 err_reg:
628 if (tbl != netns_core_table)
629 kfree(tbl);
630 err_dup:
631 return -ENOMEM;
632 }
633
sysctl_core_net_exit(struct net * net)634 static __net_exit void sysctl_core_net_exit(struct net *net)
635 {
636 struct ctl_table *tbl;
637
638 tbl = net->core.sysctl_hdr->ctl_table_arg;
639 unregister_net_sysctl_table(net->core.sysctl_hdr);
640 BUG_ON(tbl == netns_core_table);
641 kfree(tbl);
642 }
643
644 static __net_initdata struct pernet_operations sysctl_core_ops = {
645 .init = sysctl_core_net_init,
646 .exit = sysctl_core_net_exit,
647 };
648
sysctl_core_init(void)649 static __init int sysctl_core_init(void)
650 {
651 register_net_sysctl(&init_net, "net/core", net_core_table);
652 return register_pernet_subsys(&sysctl_core_ops);
653 }
654
655 fs_initcall(sysctl_core_init);
656
