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(size: 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(uuid: buf) || |
134 | add_uevent_var(env, format: "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, delim: '='); |
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, delim: ' '); |
165 | if (!next) |
166 | goto out; |
167 | |
168 | if (add_uevent_var(env, format: "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(objp: 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, type: &action, args: &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, envp: no_uuid_envp); |
209 | goto out; |
210 | } |
211 | |
212 | r = kobject_action_args(buf: action_args, |
213 | count: count - (action_args - buf), ret_env: &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, envp: env->envp); |
223 | kfree(objp: 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(objp: 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 buffer_size = sizeof(env->buf) - env->buflen; |
255 | int len; |
256 | |
257 | len = strscpy(p: &env->buf[env->buflen], q: subsystem, size: buffer_size); |
258 | if (len < 0) { |
259 | pr_warn("%s: insufficient buffer space (%u left) for %s\n" , |
260 | __func__, buffer_size, subsystem); |
261 | return -ENOMEM; |
262 | } |
263 | |
264 | env->argv[0] = uevent_helper; |
265 | env->argv[1] = &env->buf[env->buflen]; |
266 | env->argv[2] = NULL; |
267 | |
268 | env->buflen += len + 1; |
269 | return 0; |
270 | } |
271 | |
272 | static void cleanup_uevent_env(struct subprocess_info *info) |
273 | { |
274 | kfree(objp: info->data); |
275 | } |
276 | #endif |
277 | |
278 | #ifdef CONFIG_NET |
279 | static struct sk_buff *alloc_uevent_skb(struct kobj_uevent_env *env, |
280 | const char *action_string, |
281 | const char *devpath) |
282 | { |
283 | struct netlink_skb_parms *parms; |
284 | struct sk_buff *skb = NULL; |
285 | char *scratch; |
286 | size_t len; |
287 | |
288 | /* allocate message with maximum possible size */ |
289 | len = strlen(action_string) + strlen(devpath) + 2; |
290 | skb = alloc_skb(size: len + env->buflen, GFP_KERNEL); |
291 | if (!skb) |
292 | return NULL; |
293 | |
294 | /* add header */ |
295 | scratch = skb_put(skb, len); |
296 | sprintf(buf: scratch, fmt: "%s@%s" , action_string, devpath); |
297 | |
298 | skb_put_data(skb, data: env->buf, len: env->buflen); |
299 | |
300 | parms = &NETLINK_CB(skb); |
301 | parms->creds.uid = GLOBAL_ROOT_UID; |
302 | parms->creds.gid = GLOBAL_ROOT_GID; |
303 | parms->dst_group = 1; |
304 | parms->portid = 0; |
305 | |
306 | return skb; |
307 | } |
308 | |
309 | static int uevent_net_broadcast_untagged(struct kobj_uevent_env *env, |
310 | const char *action_string, |
311 | const char *devpath) |
312 | { |
313 | struct sk_buff *skb = NULL; |
314 | struct uevent_sock *ue_sk; |
315 | int retval = 0; |
316 | |
317 | /* send netlink message */ |
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(sk: uevent_sock, group: 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(ssk: uevent_sock, skb: skb_get(skb), portid: 0, group: 1, |
332 | GFP_KERNEL); |
333 | /* ENOBUFS should be handled in userspace */ |
334 | if (retval == -ENOBUFS || retval == -ESRCH) |
335 | retval = 0; |
336 | } |
337 | consume_skb(skb); |
338 | |
339 | return retval; |
340 | } |
341 | |
342 | static int uevent_net_broadcast_tagged(struct sock *usk, |
343 | struct kobj_uevent_env *env, |
344 | const char *action_string, |
345 | const char *devpath) |
346 | { |
347 | struct user_namespace *owning_user_ns = sock_net(sk: usk)->user_ns; |
348 | struct sk_buff *skb = NULL; |
349 | int ret = 0; |
350 | |
351 | skb = alloc_uevent_skb(env, action_string, devpath); |
352 | if (!skb) |
353 | return -ENOMEM; |
354 | |
355 | /* fix credentials */ |
356 | if (owning_user_ns != &init_user_ns) { |
357 | struct netlink_skb_parms *parms = &NETLINK_CB(skb); |
358 | kuid_t root_uid; |
359 | kgid_t root_gid; |
360 | |
361 | /* fix uid */ |
362 | root_uid = make_kuid(from: owning_user_ns, uid: 0); |
363 | if (uid_valid(uid: root_uid)) |
364 | parms->creds.uid = root_uid; |
365 | |
366 | /* fix gid */ |
367 | root_gid = make_kgid(from: owning_user_ns, gid: 0); |
368 | if (gid_valid(gid: root_gid)) |
369 | parms->creds.gid = root_gid; |
370 | } |
371 | |
372 | ret = netlink_broadcast(ssk: usk, skb, portid: 0, group: 1, GFP_KERNEL); |
373 | /* ENOBUFS should be handled in userspace */ |
374 | if (ret == -ENOBUFS || ret == -ESRCH) |
375 | ret = 0; |
376 | |
377 | return ret; |
378 | } |
379 | #endif |
380 | |
381 | static int kobject_uevent_net_broadcast(struct kobject *kobj, |
382 | struct kobj_uevent_env *env, |
383 | const char *action_string, |
384 | const char *devpath) |
385 | { |
386 | int ret = 0; |
387 | |
388 | #ifdef CONFIG_NET |
389 | const struct kobj_ns_type_operations *ops; |
390 | const struct net *net = NULL; |
391 | |
392 | ops = kobj_ns_ops(kobj); |
393 | if (!ops && kobj->kset) { |
394 | struct kobject *ksobj = &kobj->kset->kobj; |
395 | |
396 | if (ksobj->parent != NULL) |
397 | ops = kobj_ns_ops(kobj: ksobj->parent); |
398 | } |
399 | |
400 | /* kobjects currently only carry network namespace tags and they |
401 | * are the only tag relevant here since we want to decide which |
402 | * network namespaces to broadcast the uevent into. |
403 | */ |
404 | if (ops && ops->netlink_ns && kobj->ktype->namespace) |
405 | if (ops->type == KOBJ_NS_TYPE_NET) |
406 | net = kobj->ktype->namespace(kobj); |
407 | |
408 | if (!net) |
409 | ret = uevent_net_broadcast_untagged(env, action_string, |
410 | devpath); |
411 | else |
412 | ret = uevent_net_broadcast_tagged(usk: net->uevent_sock->sk, env, |
413 | action_string, devpath); |
414 | #endif |
415 | |
416 | return ret; |
417 | } |
418 | |
419 | static void zap_modalias_env(struct kobj_uevent_env *env) |
420 | { |
421 | static const char modalias_prefix[] = "MODALIAS=" ; |
422 | size_t len; |
423 | int i, j; |
424 | |
425 | for (i = 0; i < env->envp_idx;) { |
426 | if (strncmp(env->envp[i], modalias_prefix, |
427 | sizeof(modalias_prefix) - 1)) { |
428 | i++; |
429 | continue; |
430 | } |
431 | |
432 | len = strlen(env->envp[i]) + 1; |
433 | |
434 | if (i != env->envp_idx - 1) { |
435 | memmove(env->envp[i], env->envp[i + 1], |
436 | env->buflen - len); |
437 | |
438 | for (j = i; j < env->envp_idx - 1; j++) |
439 | env->envp[j] = env->envp[j + 1] - len; |
440 | } |
441 | |
442 | env->envp_idx--; |
443 | env->buflen -= len; |
444 | } |
445 | } |
446 | |
447 | /** |
448 | * kobject_uevent_env - send an uevent with environmental data |
449 | * |
450 | * @kobj: struct kobject that the action is happening to |
451 | * @action: action that is happening |
452 | * @envp_ext: pointer to environmental data |
453 | * |
454 | * Returns 0 if kobject_uevent_env() is completed with success or the |
455 | * corresponding error when it fails. |
456 | */ |
457 | int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, |
458 | char *envp_ext[]) |
459 | { |
460 | struct kobj_uevent_env *env; |
461 | const char *action_string = kobject_actions[action]; |
462 | const char *devpath = NULL; |
463 | const char *subsystem; |
464 | struct kobject *top_kobj; |
465 | struct kset *kset; |
466 | const struct kset_uevent_ops *uevent_ops; |
467 | int i = 0; |
468 | int retval = 0; |
469 | |
470 | /* |
471 | * Mark "remove" event done regardless of result, for some subsystems |
472 | * do not want to re-trigger "remove" event via automatic cleanup. |
473 | */ |
474 | if (action == KOBJ_REMOVE) |
475 | kobj->state_remove_uevent_sent = 1; |
476 | |
477 | pr_debug("kobject: '%s' (%p): %s\n" , |
478 | kobject_name(kobj), kobj, __func__); |
479 | |
480 | /* search the kset we belong to */ |
481 | top_kobj = kobj; |
482 | while (!top_kobj->kset && top_kobj->parent) |
483 | top_kobj = top_kobj->parent; |
484 | |
485 | if (!top_kobj->kset) { |
486 | pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " |
487 | "without kset!\n" , kobject_name(kobj), kobj, |
488 | __func__); |
489 | return -EINVAL; |
490 | } |
491 | |
492 | kset = top_kobj->kset; |
493 | uevent_ops = kset->uevent_ops; |
494 | |
495 | /* skip the event, if uevent_suppress is set*/ |
496 | if (kobj->uevent_suppress) { |
497 | pr_debug("kobject: '%s' (%p): %s: uevent_suppress " |
498 | "caused the event to drop!\n" , |
499 | kobject_name(kobj), kobj, __func__); |
500 | return 0; |
501 | } |
502 | /* skip the event, if the filter returns zero. */ |
503 | if (uevent_ops && uevent_ops->filter) |
504 | if (!uevent_ops->filter(kobj)) { |
505 | pr_debug("kobject: '%s' (%p): %s: filter function " |
506 | "caused the event to drop!\n" , |
507 | kobject_name(kobj), kobj, __func__); |
508 | return 0; |
509 | } |
510 | |
511 | /* originating subsystem */ |
512 | if (uevent_ops && uevent_ops->name) |
513 | subsystem = uevent_ops->name(kobj); |
514 | else |
515 | subsystem = kobject_name(kobj: &kset->kobj); |
516 | if (!subsystem) { |
517 | pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " |
518 | "event to drop!\n" , kobject_name(kobj), kobj, |
519 | __func__); |
520 | return 0; |
521 | } |
522 | |
523 | /* environment buffer */ |
524 | env = kzalloc(size: sizeof(struct kobj_uevent_env), GFP_KERNEL); |
525 | if (!env) |
526 | return -ENOMEM; |
527 | |
528 | /* complete object path */ |
529 | devpath = kobject_get_path(kobj, GFP_KERNEL); |
530 | if (!devpath) { |
531 | retval = -ENOENT; |
532 | goto exit; |
533 | } |
534 | |
535 | /* default keys */ |
536 | retval = add_uevent_var(env, format: "ACTION=%s" , action_string); |
537 | if (retval) |
538 | goto exit; |
539 | retval = add_uevent_var(env, format: "DEVPATH=%s" , devpath); |
540 | if (retval) |
541 | goto exit; |
542 | retval = add_uevent_var(env, format: "SUBSYSTEM=%s" , subsystem); |
543 | if (retval) |
544 | goto exit; |
545 | |
546 | /* keys passed in from the caller */ |
547 | if (envp_ext) { |
548 | for (i = 0; envp_ext[i]; i++) { |
549 | retval = add_uevent_var(env, format: "%s" , envp_ext[i]); |
550 | if (retval) |
551 | goto exit; |
552 | } |
553 | } |
554 | |
555 | /* let the kset specific function add its stuff */ |
556 | if (uevent_ops && uevent_ops->uevent) { |
557 | retval = uevent_ops->uevent(kobj, env); |
558 | if (retval) { |
559 | pr_debug("kobject: '%s' (%p): %s: uevent() returned " |
560 | "%d\n" , kobject_name(kobj), kobj, |
561 | __func__, retval); |
562 | goto exit; |
563 | } |
564 | } |
565 | |
566 | switch (action) { |
567 | case KOBJ_ADD: |
568 | /* |
569 | * Mark "add" event so we can make sure we deliver "remove" |
570 | * event to userspace during automatic cleanup. If |
571 | * the object did send an "add" event, "remove" will |
572 | * automatically generated by the core, if not already done |
573 | * by the caller. |
574 | */ |
575 | kobj->state_add_uevent_sent = 1; |
576 | break; |
577 | |
578 | case KOBJ_UNBIND: |
579 | zap_modalias_env(env); |
580 | break; |
581 | |
582 | default: |
583 | break; |
584 | } |
585 | |
586 | mutex_lock(&uevent_sock_mutex); |
587 | /* we will send an event, so request a new sequence number */ |
588 | retval = add_uevent_var(env, format: "SEQNUM=%llu" , ++uevent_seqnum); |
589 | if (retval) { |
590 | mutex_unlock(lock: &uevent_sock_mutex); |
591 | goto exit; |
592 | } |
593 | retval = kobject_uevent_net_broadcast(kobj, env, action_string, |
594 | devpath); |
595 | mutex_unlock(lock: &uevent_sock_mutex); |
596 | |
597 | #ifdef CONFIG_UEVENT_HELPER |
598 | /* call uevent_helper, usually only enabled during early boot */ |
599 | if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { |
600 | struct subprocess_info *info; |
601 | |
602 | retval = add_uevent_var(env, format: "HOME=/" ); |
603 | if (retval) |
604 | goto exit; |
605 | retval = add_uevent_var(env, |
606 | format: "PATH=/sbin:/bin:/usr/sbin:/usr/bin" ); |
607 | if (retval) |
608 | goto exit; |
609 | retval = init_uevent_argv(env, subsystem); |
610 | if (retval) |
611 | goto exit; |
612 | |
613 | retval = -ENOMEM; |
614 | info = call_usermodehelper_setup(path: env->argv[0], argv: env->argv, |
615 | envp: env->envp, GFP_KERNEL, |
616 | NULL, cleanup: cleanup_uevent_env, data: env); |
617 | if (info) { |
618 | retval = call_usermodehelper_exec(info, UMH_NO_WAIT); |
619 | env = NULL; /* freed by cleanup_uevent_env */ |
620 | } |
621 | } |
622 | #endif |
623 | |
624 | exit: |
625 | kfree(objp: devpath); |
626 | kfree(objp: env); |
627 | return retval; |
628 | } |
629 | EXPORT_SYMBOL_GPL(kobject_uevent_env); |
630 | |
631 | /** |
632 | * kobject_uevent - notify userspace by sending an uevent |
633 | * |
634 | * @kobj: struct kobject that the action is happening to |
635 | * @action: action that is happening |
636 | * |
637 | * Returns 0 if kobject_uevent() is completed with success or the |
638 | * corresponding error when it fails. |
639 | */ |
640 | int kobject_uevent(struct kobject *kobj, enum kobject_action action) |
641 | { |
642 | return kobject_uevent_env(kobj, action, NULL); |
643 | } |
644 | EXPORT_SYMBOL_GPL(kobject_uevent); |
645 | |
646 | /** |
647 | * add_uevent_var - add key value string to the environment buffer |
648 | * @env: environment buffer structure |
649 | * @format: printf format for the key=value pair |
650 | * |
651 | * Returns 0 if environment variable was added successfully or -ENOMEM |
652 | * if no space was available. |
653 | */ |
654 | int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) |
655 | { |
656 | va_list args; |
657 | int len; |
658 | |
659 | if (env->envp_idx >= ARRAY_SIZE(env->envp)) { |
660 | WARN(1, KERN_ERR "add_uevent_var: too many keys\n" ); |
661 | return -ENOMEM; |
662 | } |
663 | |
664 | va_start(args, format); |
665 | len = vsnprintf(buf: &env->buf[env->buflen], |
666 | size: sizeof(env->buf) - env->buflen, |
667 | fmt: format, args); |
668 | va_end(args); |
669 | |
670 | if (len >= (sizeof(env->buf) - env->buflen)) { |
671 | WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n" ); |
672 | return -ENOMEM; |
673 | } |
674 | |
675 | env->envp[env->envp_idx++] = &env->buf[env->buflen]; |
676 | env->buflen += len + 1; |
677 | return 0; |
678 | } |
679 | EXPORT_SYMBOL_GPL(add_uevent_var); |
680 | |
681 | #if defined(CONFIG_NET) |
682 | static int uevent_net_broadcast(struct sock *usk, struct sk_buff *skb, |
683 | struct netlink_ext_ack *extack) |
684 | { |
685 | /* u64 to chars: 2^64 - 1 = 21 chars */ |
686 | char buf[sizeof("SEQNUM=" ) + 21]; |
687 | struct sk_buff *skbc; |
688 | int ret; |
689 | |
690 | /* bump and prepare sequence number */ |
691 | ret = snprintf(buf, size: sizeof(buf), fmt: "SEQNUM=%llu" , ++uevent_seqnum); |
692 | if (ret < 0 || (size_t)ret >= sizeof(buf)) |
693 | return -ENOMEM; |
694 | ret++; |
695 | |
696 | /* verify message does not overflow */ |
697 | if ((skb->len + ret) > UEVENT_BUFFER_SIZE) { |
698 | NL_SET_ERR_MSG(extack, "uevent message too big" ); |
699 | return -EINVAL; |
700 | } |
701 | |
702 | /* copy skb and extend to accommodate sequence number */ |
703 | skbc = skb_copy_expand(skb, newheadroom: 0, newtailroom: ret, GFP_KERNEL); |
704 | if (!skbc) |
705 | return -ENOMEM; |
706 | |
707 | /* append sequence number */ |
708 | skb_put_data(skb: skbc, data: buf, len: ret); |
709 | |
710 | /* remove msg header */ |
711 | skb_pull(skb: skbc, NLMSG_HDRLEN); |
712 | |
713 | /* set portid 0 to inform userspace message comes from kernel */ |
714 | NETLINK_CB(skbc).portid = 0; |
715 | NETLINK_CB(skbc).dst_group = 1; |
716 | |
717 | ret = netlink_broadcast(ssk: usk, skb: skbc, portid: 0, group: 1, GFP_KERNEL); |
718 | /* ENOBUFS should be handled in userspace */ |
719 | if (ret == -ENOBUFS || ret == -ESRCH) |
720 | ret = 0; |
721 | |
722 | return ret; |
723 | } |
724 | |
725 | static int uevent_net_rcv_skb(struct sk_buff *skb, struct nlmsghdr *nlh, |
726 | struct netlink_ext_ack *extack) |
727 | { |
728 | struct net *net; |
729 | int ret; |
730 | |
731 | if (!nlmsg_data(nlh)) |
732 | return -EINVAL; |
733 | |
734 | /* |
735 | * Verify that we are allowed to send messages to the target |
736 | * network namespace. The caller must have CAP_SYS_ADMIN in the |
737 | * owning user namespace of the target network namespace. |
738 | */ |
739 | net = sock_net(NETLINK_CB(skb).sk); |
740 | if (!netlink_ns_capable(skb, ns: net->user_ns, CAP_SYS_ADMIN)) { |
741 | NL_SET_ERR_MSG(extack, "missing CAP_SYS_ADMIN capability" ); |
742 | return -EPERM; |
743 | } |
744 | |
745 | mutex_lock(&uevent_sock_mutex); |
746 | ret = uevent_net_broadcast(usk: net->uevent_sock->sk, skb, extack); |
747 | mutex_unlock(lock: &uevent_sock_mutex); |
748 | |
749 | return ret; |
750 | } |
751 | |
752 | static void uevent_net_rcv(struct sk_buff *skb) |
753 | { |
754 | netlink_rcv_skb(skb, cb: &uevent_net_rcv_skb); |
755 | } |
756 | |
757 | static int uevent_net_init(struct net *net) |
758 | { |
759 | struct uevent_sock *ue_sk; |
760 | struct netlink_kernel_cfg cfg = { |
761 | .groups = 1, |
762 | .input = uevent_net_rcv, |
763 | .flags = NL_CFG_F_NONROOT_RECV |
764 | }; |
765 | |
766 | ue_sk = kzalloc(size: sizeof(*ue_sk), GFP_KERNEL); |
767 | if (!ue_sk) |
768 | return -ENOMEM; |
769 | |
770 | ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, cfg: &cfg); |
771 | if (!ue_sk->sk) { |
772 | pr_err("kobject_uevent: unable to create netlink socket!\n" ); |
773 | kfree(objp: ue_sk); |
774 | return -ENODEV; |
775 | } |
776 | |
777 | net->uevent_sock = ue_sk; |
778 | |
779 | /* Restrict uevents to initial user namespace. */ |
780 | if (sock_net(sk: ue_sk->sk)->user_ns == &init_user_ns) { |
781 | mutex_lock(&uevent_sock_mutex); |
782 | list_add_tail(new: &ue_sk->list, head: &uevent_sock_list); |
783 | mutex_unlock(lock: &uevent_sock_mutex); |
784 | } |
785 | |
786 | return 0; |
787 | } |
788 | |
789 | static void uevent_net_exit(struct net *net) |
790 | { |
791 | struct uevent_sock *ue_sk = net->uevent_sock; |
792 | |
793 | if (sock_net(sk: ue_sk->sk)->user_ns == &init_user_ns) { |
794 | mutex_lock(&uevent_sock_mutex); |
795 | list_del(entry: &ue_sk->list); |
796 | mutex_unlock(lock: &uevent_sock_mutex); |
797 | } |
798 | |
799 | netlink_kernel_release(sk: ue_sk->sk); |
800 | kfree(objp: ue_sk); |
801 | } |
802 | |
803 | static struct pernet_operations uevent_net_ops = { |
804 | .init = uevent_net_init, |
805 | .exit = uevent_net_exit, |
806 | }; |
807 | |
808 | static int __init kobject_uevent_init(void) |
809 | { |
810 | return register_pernet_subsys(&uevent_net_ops); |
811 | } |
812 | |
813 | |
814 | postcore_initcall(kobject_uevent_init); |
815 | #endif |
816 | |