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