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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * kernel userspace event delivery
4 *
5 * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
6 * Copyright (C) 2004 Novell, Inc. All rights reserved.
7 * Copyright (C) 2004 IBM, Inc. All rights reserved.
8 *
9 * Authors:
10 * Robert Love <[email protected]>
11 * Kay Sievers <[email protected]>
12 * Arjan van de Ven <[email protected]>
13 * Greg Kroah-Hartman <[email protected]>
14 */
15
16#include <linux/spinlock.h>
17#include <linux/string.h>
18#include <linux/kobject.h>
19#include <linux/export.h>
20#include <linux/kmod.h>
21#include <linux/slab.h>
22#include <linux/socket.h>
23#include <linux/skbuff.h>
24#include <linux/netlink.h>
25#include <linux/uidgid.h>
26#include <linux/uuid.h>
27#include <linux/ctype.h>
28#include <net/sock.h>
29#include <net/netlink.h>
30#include <net/net_namespace.h>
31
32
33atomic64_t uevent_seqnum;
34#ifdef CONFIG_UEVENT_HELPER
35char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
36#endif
37
38struct uevent_sock {
39 struct list_head list;
40 struct sock *sk;
41};
42
43#ifdef CONFIG_NET
44static LIST_HEAD(uevent_sock_list);
45/* This lock protects uevent_sock_list */
46static DEFINE_MUTEX(uevent_sock_mutex);
47#endif
48
49/* the strings here must match the enum in include/linux/kobject.h */
50static const char *kobject_actions[] = {
51 [KOBJ_ADD] = "add",
52 [KOBJ_REMOVE] = "remove",
53 [KOBJ_CHANGE] = "change",
54 [KOBJ_MOVE] = "move",
55 [KOBJ_ONLINE] = "online",
56 [KOBJ_OFFLINE] = "offline",
57 [KOBJ_BIND] = "bind",
58 [KOBJ_UNBIND] = "unbind",
59};
60
61static int kobject_action_type(const char *buf, size_t count,
62 enum kobject_action *type,
63 const char **args)
64{
65 enum kobject_action action;
66 size_t count_first;
67 const char *args_start;
68 int ret = -EINVAL;
69
70 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0'))
71 count--;
72
73 if (!count)
74 goto out;
75
76 args_start = strnchr(buf, count, ' ');
77 if (args_start) {
78 count_first = args_start - buf;
79 args_start = args_start + 1;
80 } else
81 count_first = count;
82
83 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
84 if (strncmp(kobject_actions[action], buf, count_first) != 0)
85 continue;
86 if (kobject_actions[action][count_first] != '\0')
87 continue;
88 if (args)
89 *args = args_start;
90 *type = action;
91 ret = 0;
92 break;
93 }
94out:
95 return ret;
96}
97
98static const char *action_arg_word_end(const char *buf, const char *buf_end,
99 char delim)
100{
101 const char *next = buf;
102
103 while (next <= buf_end && *next != delim)
104 if (!isalnum(*next++))
105 return NULL;
106
107 if (next == buf)
108 return NULL;
109
110 return next;
111}
112
113static int kobject_action_args(const char *buf, size_t count,
114 struct kobj_uevent_env **ret_env)
115{
116 struct kobj_uevent_env *env = NULL;
117 const char *next, *buf_end, *key;
118 int key_len;
119 int r = -EINVAL;
120
121 if (count && (buf[count - 1] == '\n' || buf[count - 1] == '\0'))
122 count--;
123
124 if (!count)
125 return -EINVAL;
126
127 env = kzalloc_obj(*env);
128 if (!env)
129 return -ENOMEM;
130
131 /* first arg is UUID */
132 if (count < UUID_STRING_LEN || !uuid_is_valid(buf) ||
133 add_uevent_var(env, "SYNTH_UUID=%.*s", UUID_STRING_LEN, buf))
134 goto out;
135
136 /*
137 * the rest are custom environment variables in KEY=VALUE
138 * format with ' ' delimiter between each KEY=VALUE pair
139 */
140 next = buf + UUID_STRING_LEN;
141 buf_end = buf + count - 1;
142
143 while (next <= buf_end) {
144 if (*next != ' ')
145 goto out;
146
147 /* skip the ' ', key must follow */
148 key = ++next;
149 if (key > buf_end)
150 goto out;
151
152 buf = next;
153 next = action_arg_word_end(buf, buf_end, '=');
154 if (!next || next > buf_end || *next != '=')
155 goto out;
156 key_len = next - buf;
157
158 /* skip the '=', value must follow */
159 if (++next > buf_end)
160 goto out;
161
162 buf = next;
163 next = action_arg_word_end(buf, buf_end, ' ');
164 if (!next)
165 goto out;
166
167 if (add_uevent_var(env, "SYNTH_ARG_%.*s=%.*s",
168 key_len, key, (int) (next - buf), buf))
169 goto out;
170 }
171
172 r = 0;
173out:
174 if (r)
175 kfree(env);
176 else
177 *ret_env = env;
178 return r;
179}
180
181/**
182 * kobject_synth_uevent - send synthetic uevent with arguments
183 *
184 * @kobj: struct kobject for which synthetic uevent is to be generated
185 * @buf: buffer containing action type and action args, newline is ignored
186 * @count: length of buffer
187 *
188 * Returns 0 if kobject_synthetic_uevent() is completed with success or the
189 * corresponding error when it fails.
190 */
191int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
192{
193 char *no_uuid_envp[] = { "SYNTH_UUID=0", NULL };
194 enum kobject_action action;
195 const char *action_args;
196 struct kobj_uevent_env *env;
197 const char *msg = NULL, *devpath;
198 int r;
199
200 r = kobject_action_type(buf, count, &action, &action_args);
201 if (r) {
202 msg = "unknown uevent action string";
203 goto out;
204 }
205
206 if (!action_args) {
207 r = kobject_uevent_env(kobj, action, no_uuid_envp);
208 goto out;
209 }
210
211 r = kobject_action_args(action_args,
212 count - (action_args - buf), &env);
213 if (r == -EINVAL) {
214 msg = "incorrect uevent action arguments";
215 goto out;
216 }
217
218 if (r)
219 goto out;
220
221 r = kobject_uevent_env(kobj, action, env->envp);
222 kfree(env);
223out:
224 if (r) {
225 devpath = kobject_get_path(kobj, GFP_KERNEL);
226 pr_warn("synth uevent: %s: %s\n",
227 devpath ?: "unknown device",
228 msg ?: "failed to send uevent");
229 kfree(devpath);
230 }
231 return r;
232}
233
234#ifdef CONFIG_UEVENT_HELPER
235static int kobj_usermode_filter(struct kobject *kobj)
236{
237 const struct kobj_ns_type_operations *ops;
238
239 ops = kobj_ns_ops(kobj);
240 if (ops) {
241 const struct ns_common *init_ns, *ns;
242
243 ns = kobj->ktype->namespace(kobj);
244 init_ns = ops->initial_ns();
245 return ns != init_ns;
246 }
247
248 return 0;
249}
250
251static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem)
252{
253 int buffer_size = sizeof(env->buf) - env->buflen;
254 int len;
255
256 len = strscpy(&env->buf[env->buflen], subsystem, buffer_size);
257 if (len < 0) {
258 pr_warn("%s: insufficient buffer space (%u left) for %s\n",
259 __func__, buffer_size, subsystem);
260 return -ENOMEM;
261 }
262
263 env->argv[0] = uevent_helper;
264 env->argv[1] = &env->buf[env->buflen];
265 env->argv[2] = NULL;
266
267 env->buflen += len + 1;
268 return 0;
269}
270
271static void cleanup_uevent_env(struct subprocess_info *info)
272{
273 kfree(info->data);
274}
275#endif
276
277#ifdef CONFIG_NET
278static struct sk_buff *alloc_uevent_skb(struct kobj_uevent_env *env,
279 const char *action_string,
280 const char *devpath)
281{
282 struct netlink_skb_parms *parms;
283 struct sk_buff *skb = NULL;
284 char *scratch;
285 size_t len;
286
287 /* allocate message with maximum possible size */
288 len = strlen(action_string) + strlen(devpath) + 2;
289 skb = alloc_skb(len + env->buflen, GFP_KERNEL);
290 if (!skb)
291 return NULL;
292
293 /* add header */
294 scratch = skb_put(skb, len);
295 sprintf(scratch, "%s@%s", action_string, devpath);
296
297 skb_put_data(skb, env->buf, env->buflen);
298
299 parms = &NETLINK_CB(skb);
300 parms->creds.uid = GLOBAL_ROOT_UID;
301 parms->creds.gid = GLOBAL_ROOT_GID;
302 parms->dst_group = 1;
303 parms->portid = 0;
304
305 return skb;
306}
307
308static int uevent_net_broadcast_untagged(struct kobj_uevent_env *env,
309 const char *action_string,
310 const char *devpath)
311{
312 struct sk_buff *skb = NULL;
313 struct uevent_sock *ue_sk;
314 int retval = 0;
315
316 /* send netlink message */
317 mutex_lock(&uevent_sock_mutex);
318 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
319 struct sock *uevent_sock = ue_sk->sk;
320
321 if (!netlink_has_listeners(uevent_sock, 1))
322 continue;
323
324 if (!skb) {
325 retval = -ENOMEM;
326 skb = alloc_uevent_skb(env, action_string, devpath);
327 if (!skb)
328 continue;
329 }
330
331 retval = netlink_broadcast(uevent_sock, skb_get(skb), 0, 1,
332 GFP_KERNEL);
333 /* ENOBUFS should be handled in userspace */
334 if (retval == -ENOBUFS || retval == -ESRCH)
335 retval = 0;
336 }
337 mutex_unlock(&uevent_sock_mutex);
338 consume_skb(skb);
339
340 return retval;
341}
342
343static int uevent_net_broadcast_tagged(struct sock *usk,
344 struct kobj_uevent_env *env,
345 const char *action_string,
346 const char *devpath)
347{
348 struct user_namespace *owning_user_ns = sock_net(usk)->user_ns;
349 struct sk_buff *skb = NULL;
350 int ret = 0;
351
352 skb = alloc_uevent_skb(env, action_string, devpath);
353 if (!skb)
354 return -ENOMEM;
355
356 /* fix credentials */
357 if (owning_user_ns != &init_user_ns) {
358 struct netlink_skb_parms *parms = &NETLINK_CB(skb);
359 kuid_t root_uid;
360 kgid_t root_gid;
361
362 /* fix uid */
363 root_uid = make_kuid(owning_user_ns, 0);
364 if (uid_valid(root_uid))
365 parms->creds.uid = root_uid;
366
367 /* fix gid */
368 root_gid = make_kgid(owning_user_ns, 0);
369 if (gid_valid(root_gid))
370 parms->creds.gid = root_gid;
371 }
372
373 ret = netlink_broadcast(usk, skb, 0, 1, GFP_KERNEL);
374 /* ENOBUFS should be handled in userspace */
375 if (ret == -ENOBUFS || ret == -ESRCH)
376 ret = 0;
377
378 return ret;
379}
380#endif
381
382static int kobject_uevent_net_broadcast(struct kobject *kobj,
383 struct kobj_uevent_env *env,
384 const char *action_string,
385 const char *devpath)
386{
387 int ret = 0;
388
389#ifdef CONFIG_NET
390 const struct kobj_ns_type_operations *ops;
391 const struct ns_common *ns = NULL;
392
393 ops = kobj_ns_ops(kobj);
394 if (!ops && kobj->kset) {
395 struct kobject *ksobj = &kobj->kset->kobj;
396
397 if (ksobj->parent != NULL)
398 ops = kobj_ns_ops(ksobj->parent);
399 }
400
401 /* kobjects currently only carry network namespace tags and they
402 * are the only tag relevant here since we want to decide which
403 * network namespaces to broadcast the uevent into.
404 */
405 if (ops && ops->netlink_ns && kobj->ktype->namespace)
406 if (ops->type == KOBJ_NS_TYPE_NET)
407 ns = kobj->ktype->namespace(kobj);
408
409 if (!ns)
410 ret = uevent_net_broadcast_untagged(env, action_string,
411 devpath);
412 else {
413 const struct net *net = container_of(ns, struct net, ns);
414
415 ret = uevent_net_broadcast_tagged(net->uevent_sock->sk, env,
416 action_string, devpath);
417 }
418#endif
419
420 return ret;
421}
422
423static void zap_modalias_env(struct kobj_uevent_env *env)
424{
425 static const char modalias_prefix[] = "MODALIAS=";
426 size_t len;
427 int i, j;
428
429 for (i = 0; i < env->envp_idx;) {
430 if (strncmp(env->envp[i], modalias_prefix,
431 sizeof(modalias_prefix) - 1)) {
432 i++;
433 continue;
434 }
435
436 len = strlen(env->envp[i]) + 1;
437
438 if (i != env->envp_idx - 1) {
439 /* @env->envp[] contains pointers to @env->buf[]
440 * with @env->buflen chars, and we are removing
441 * variable MODALIAS here pointed by @env->envp[i]
442 * with length @len as shown below:
443 *
444 * 0 @env->buf[] @env->buflen
445 * ---------------------------------------------
446 * ^ ^ ^ ^
447 * | |-> @len <-| target block |
448 * @env->envp[0] @env->envp[i] @env->envp[i + 1]
449 *
450 * so the "target block" indicated above is moved
451 * backward by @len, and its right size is
452 * @env->buflen - (@env->envp[i + 1] - @env->envp[0]).
453 */
454 memmove(env->envp[i], env->envp[i + 1],
455 env->buflen - (env->envp[i + 1] - env->envp[0]));
456
457 for (j = i; j < env->envp_idx - 1; j++)
458 env->envp[j] = env->envp[j + 1] - len;
459 }
460
461 env->envp_idx--;
462 env->buflen -= len;
463 }
464}
465
466/**
467 * kobject_uevent_env - send an uevent with environmental data
468 *
469 * @kobj: struct kobject that the action is happening to
470 * @action: action that is happening
471 * @envp_ext: pointer to environmental data
472 *
473 * Returns 0 if kobject_uevent_env() is completed with success or the
474 * corresponding error when it fails.
475 */
476int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
477 char *envp_ext[])
478{
479 struct kobj_uevent_env *env;
480 const char *action_string = kobject_actions[action];
481 const char *devpath = NULL;
482 const char *subsystem;
483 struct kobject *top_kobj;
484 struct kset *kset;
485 const struct kset_uevent_ops *uevent_ops;
486 int i = 0;
487 int retval = 0;
488
489 /*
490 * Mark "remove" event done regardless of result, for some subsystems
491 * do not want to re-trigger "remove" event via automatic cleanup.
492 */
493 if (action == KOBJ_REMOVE)
494 kobj->state_remove_uevent_sent = 1;
495
496 pr_debug("kobject: '%s' (%p): %s\n",
497 kobject_name(kobj), kobj, __func__);
498
499 /* search the kset we belong to */
500 top_kobj = kobj;
501 while (!top_kobj->kset && top_kobj->parent)
502 top_kobj = top_kobj->parent;
503
504 if (!top_kobj->kset) {
505 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
506 "without kset!\n", kobject_name(kobj), kobj,
507 __func__);
508 return -EINVAL;
509 }
510
511 kset = top_kobj->kset;
512 uevent_ops = kset->uevent_ops;
513
514 /* skip the event, if uevent_suppress is set*/
515 if (kobj->uevent_suppress) {
516 pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
517 "caused the event to drop!\n",
518 kobject_name(kobj), kobj, __func__);
519 return 0;
520 }
521 /* skip the event, if the filter returns zero. */
522 if (uevent_ops && uevent_ops->filter)
523 if (!uevent_ops->filter(kobj)) {
524 pr_debug("kobject: '%s' (%p): %s: filter function "
525 "caused the event to drop!\n",
526 kobject_name(kobj), kobj, __func__);
527 return 0;
528 }
529
530 /* originating subsystem */
531 if (uevent_ops && uevent_ops->name)
532 subsystem = uevent_ops->name(kobj);
533 else
534 subsystem = kobject_name(&kset->kobj);
535 if (!subsystem) {
536 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
537 "event to drop!\n", kobject_name(kobj), kobj,
538 __func__);
539 return 0;
540 }
541
542 /* environment buffer */
543 env = kzalloc_obj(struct kobj_uevent_env);
544 if (!env)
545 return -ENOMEM;
546
547 /* complete object path */
548 devpath = kobject_get_path(kobj, GFP_KERNEL);
549 if (!devpath) {
550 retval = -ENOENT;
551 goto exit;
552 }
553
554 /* default keys */
555 retval = add_uevent_var(env, "ACTION=%s", action_string);
556 if (retval)
557 goto exit;
558 retval = add_uevent_var(env, "DEVPATH=%s", devpath);
559 if (retval)
560 goto exit;
561 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
562 if (retval)
563 goto exit;
564
565 /* keys passed in from the caller */
566 if (envp_ext) {
567 for (i = 0; envp_ext[i]; i++) {
568 retval = add_uevent_var(env, "%s", envp_ext[i]);
569 if (retval)
570 goto exit;
571 }
572 }
573
574 /* let the kset specific function add its stuff */
575 if (uevent_ops && uevent_ops->uevent) {
576 retval = uevent_ops->uevent(kobj, env);
577 if (retval) {
578 pr_debug("kobject: '%s' (%p): %s: uevent() returned "
579 "%d\n", kobject_name(kobj), kobj,
580 __func__, retval);
581 goto exit;
582 }
583 }
584
585 switch (action) {
586 case KOBJ_ADD:
587 /*
588 * Mark "add" event so we can make sure we deliver "remove"
589 * event to userspace during automatic cleanup. If
590 * the object did send an "add" event, "remove" will
591 * automatically generated by the core, if not already done
592 * by the caller.
593 */
594 kobj->state_add_uevent_sent = 1;
595 break;
596
597 case KOBJ_UNBIND:
598 zap_modalias_env(env);
599 break;
600
601 default:
602 break;
603 }
604
605 /* we will send an event, so request a new sequence number */
606 retval = add_uevent_var(env, "SEQNUM=%llu",
607 atomic64_inc_return(&uevent_seqnum));
608 if (retval)
609 goto exit;
610
611 retval = kobject_uevent_net_broadcast(kobj, env, action_string,
612 devpath);
613
614#ifdef CONFIG_UEVENT_HELPER
615 /* call uevent_helper, usually only enabled during early boot */
616 if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
617 struct subprocess_info *info;
618
619 retval = add_uevent_var(env, "HOME=/");
620 if (retval)
621 goto exit;
622 retval = add_uevent_var(env,
623 "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
624 if (retval)
625 goto exit;
626 retval = init_uevent_argv(env, subsystem);
627 if (retval)
628 goto exit;
629
630 retval = -ENOMEM;
631 info = call_usermodehelper_setup(env->argv[0], env->argv,
632 env->envp, GFP_KERNEL,
633 NULL, cleanup_uevent_env, env);
634 if (info) {
635 retval = call_usermodehelper_exec(info, UMH_NO_WAIT);
636 env = NULL; /* freed by cleanup_uevent_env */
637 }
638 }
639#endif
640
641exit:
642 kfree(devpath);
643 kfree(env);
644 return retval;
645}
646EXPORT_SYMBOL_GPL(kobject_uevent_env);
647
648/**
649 * kobject_uevent - notify userspace by sending an uevent
650 *
651 * @kobj: struct kobject that the action is happening to
652 * @action: action that is happening
653 *
654 * Returns 0 if kobject_uevent() is completed with success or the
655 * corresponding error when it fails.
656 */
657int kobject_uevent(struct kobject *kobj, enum kobject_action action)
658{
659 return kobject_uevent_env(kobj, action, NULL);
660}
661EXPORT_SYMBOL_GPL(kobject_uevent);
662
663/**
664 * add_uevent_var - add key value string to the environment buffer
665 * @env: environment buffer structure
666 * @format: printf format for the key=value pair
667 *
668 * Returns 0 if environment variable was added successfully or -ENOMEM
669 * if no space was available.
670 */
671int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
672{
673 va_list args;
674 int len;
675
676 if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
677 WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
678 return -ENOMEM;
679 }
680
681 va_start(args, format);
682 len = vsnprintf(&env->buf[env->buflen],
683 sizeof(env->buf) - env->buflen,
684 format, args);
685 va_end(args);
686
687 if (len >= (sizeof(env->buf) - env->buflen)) {
688 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
689 return -ENOMEM;
690 }
691
692 env->envp[env->envp_idx++] = &env->buf[env->buflen];
693 env->buflen += len + 1;
694 return 0;
695}
696EXPORT_SYMBOL_GPL(add_uevent_var);
697
698#if defined(CONFIG_NET)
699static int uevent_net_broadcast(struct sock *usk, struct sk_buff *skb,
700 struct netlink_ext_ack *extack)
701{
702 /* u64 to chars: 2^64 - 1 = 21 chars */
703 char buf[sizeof("SEQNUM=") + 21];
704 struct sk_buff *skbc;
705 int ret;
706
707 /* bump and prepare sequence number */
708 ret = snprintf(buf, sizeof(buf), "SEQNUM=%llu",
709 atomic64_inc_return(&uevent_seqnum));
710 if (ret < 0 || (size_t)ret >= sizeof(buf))
711 return -ENOMEM;
712 ret++;
713
714 /* verify message does not overflow */
715 if ((skb->len + ret) > UEVENT_BUFFER_SIZE) {
716 NL_SET_ERR_MSG(extack, "uevent message too big");
717 return -EINVAL;
718 }
719
720 /* copy skb and extend to accommodate sequence number */
721 skbc = skb_copy_expand(skb, 0, ret, GFP_KERNEL);
722 if (!skbc)
723 return -ENOMEM;
724
725 /* append sequence number */
726 skb_put_data(skbc, buf, ret);
727
728 /* remove msg header */
729 skb_pull(skbc, NLMSG_HDRLEN);
730
731 /* set portid 0 to inform userspace message comes from kernel */
732 NETLINK_CB(skbc).portid = 0;
733 NETLINK_CB(skbc).dst_group = 1;
734
735 ret = netlink_broadcast(usk, skbc, 0, 1, GFP_KERNEL);
736 /* ENOBUFS should be handled in userspace */
737 if (ret == -ENOBUFS || ret == -ESRCH)
738 ret = 0;
739
740 return ret;
741}
742
743static int uevent_net_rcv_skb(struct sk_buff *skb, struct nlmsghdr *nlh,
744 struct netlink_ext_ack *extack)
745{
746 struct net *net;
747 int ret;
748
749 if (!nlmsg_data(nlh))
750 return -EINVAL;
751
752 /*
753 * Verify that we are allowed to send messages to the target
754 * network namespace. The caller must have CAP_SYS_ADMIN in the
755 * owning user namespace of the target network namespace.
756 */
757 net = sock_net(NETLINK_CB(skb).sk);
758 if (!netlink_ns_capable(skb, net->user_ns, CAP_SYS_ADMIN)) {
759 NL_SET_ERR_MSG(extack, "missing CAP_SYS_ADMIN capability");
760 return -EPERM;
761 }
762
763 ret = uevent_net_broadcast(net->uevent_sock->sk, skb, extack);
764
765 return ret;
766}
767
768static void uevent_net_rcv(struct sk_buff *skb)
769{
770 netlink_rcv_skb(skb, &uevent_net_rcv_skb);
771}
772
773static int uevent_net_init(struct net *net)
774{
775 struct uevent_sock *ue_sk;
776 struct netlink_kernel_cfg cfg = {
777 .groups = 1,
778 .input = uevent_net_rcv,
779 .flags = NL_CFG_F_NONROOT_RECV
780 };
781
782 ue_sk = kzalloc_obj(*ue_sk);
783 if (!ue_sk)
784 return -ENOMEM;
785
786 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg);
787 if (!ue_sk->sk) {
788 pr_err("kobject_uevent: unable to create netlink socket!\n");
789 kfree(ue_sk);
790 return -ENODEV;
791 }
792
793 net->uevent_sock = ue_sk;
794
795 /* Restrict uevents to initial user namespace. */
796 if (sock_net(ue_sk->sk)->user_ns == &init_user_ns) {
797 mutex_lock(&uevent_sock_mutex);
798 list_add_tail(&ue_sk->list, &uevent_sock_list);
799 mutex_unlock(&uevent_sock_mutex);
800 }
801
802 return 0;
803}
804
805static void uevent_net_exit(struct net *net)
806{
807 struct uevent_sock *ue_sk = net->uevent_sock;
808
809 if (sock_net(ue_sk->sk)->user_ns == &init_user_ns) {
810 mutex_lock(&uevent_sock_mutex);
811 list_del(&ue_sk->list);
812 mutex_unlock(&uevent_sock_mutex);
813 }
814
815 netlink_kernel_release(ue_sk->sk);
816 kfree(ue_sk);
817}
818
819static struct pernet_operations uevent_net_ops = {
820 .init = uevent_net_init,
821 .exit = uevent_net_exit,
822};
823
824static int __init kobject_uevent_init(void)
825{
826 return register_pernet_subsys(&uevent_net_ops);
827}
828
829
830postcore_initcall(kobject_uevent_init);
831#endif
832
833#ifdef CONFIG_UEVENT_HELPER
834static const struct ctl_table uevent_helper_sysctl_table[] = {
835 {
836 .procname = "hotplug",
837 .data = &uevent_helper,
838 .maxlen = UEVENT_HELPER_PATH_LEN,
839 .mode = 0644,
840 .proc_handler = proc_dostring,
841 },
842};
843
844static int __init init_uevent_helper_sysctl(void)
845{
846 register_sysctl_init("kernel", uevent_helper_sysctl_table);
847 return 0;
848}
849
850postcore_initcall(init_uevent_helper_sysctl);
851#endif