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Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | kmod, the new module loader (replaces kerneld) | |
3 | Kirk Petersen | |
4 | ||
5 | Reorganized not to be a daemon by Adam Richter, with guidance | |
6 | from Greg Zornetzer. | |
7 | ||
8 | Modified to avoid chroot and file sharing problems. | |
9 | Mikael Pettersson | |
10 | ||
11 | Limit the concurrent number of kmod modprobes to catch loops from | |
12 | "modprobe needs a service that is in a module". | |
13 | Keith Owens <kaos@ocs.com.au> December 1999 | |
14 | ||
15 | Unblock all signals when we exec a usermode process. | |
16 | Shuu Yamaguchi <shuu@wondernetworkresources.com> December 2000 | |
17 | ||
18 | call_usermodehelper wait flag, and remove exec_usermodehelper. | |
19 | Rusty Russell <rusty@rustcorp.com.au> Jan 2003 | |
20 | */ | |
1da177e4 LT |
21 | #include <linux/module.h> |
22 | #include <linux/sched.h> | |
23 | #include <linux/syscalls.h> | |
24 | #include <linux/unistd.h> | |
25 | #include <linux/kmod.h> | |
1da177e4 | 26 | #include <linux/slab.h> |
1da177e4 | 27 | #include <linux/completion.h> |
17f60a7d | 28 | #include <linux/cred.h> |
1da177e4 | 29 | #include <linux/file.h> |
9f3acc31 | 30 | #include <linux/fdtable.h> |
1da177e4 LT |
31 | #include <linux/workqueue.h> |
32 | #include <linux/security.h> | |
33 | #include <linux/mount.h> | |
34 | #include <linux/kernel.h> | |
35 | #include <linux/init.h> | |
d025c9db | 36 | #include <linux/resource.h> |
8cdd4936 RW |
37 | #include <linux/notifier.h> |
38 | #include <linux/suspend.h> | |
b298d289 | 39 | #include <linux/rwsem.h> |
a74fb73c | 40 | #include <linux/ptrace.h> |
0fdff3ec | 41 | #include <linux/async.h> |
1da177e4 LT |
42 | #include <asm/uaccess.h> |
43 | ||
7ead8b83 LZ |
44 | #include <trace/events/module.h> |
45 | ||
1da177e4 LT |
46 | extern int max_threads; |
47 | ||
48 | static struct workqueue_struct *khelper_wq; | |
49 | ||
17f60a7d EP |
50 | #define CAP_BSET (void *)1 |
51 | #define CAP_PI (void *)2 | |
52 | ||
53 | static kernel_cap_t usermodehelper_bset = CAP_FULL_SET; | |
54 | static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET; | |
55 | static DEFINE_SPINLOCK(umh_sysctl_lock); | |
b298d289 | 56 | static DECLARE_RWSEM(umhelper_sem); |
17f60a7d | 57 | |
a1ef5adb | 58 | #ifdef CONFIG_MODULES |
1da177e4 LT |
59 | |
60 | /* | |
61 | modprobe_path is set via /proc/sys. | |
62 | */ | |
63 | char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; | |
64 | ||
1cc684ab ON |
65 | static void free_modprobe_argv(struct subprocess_info *info) |
66 | { | |
67 | kfree(info->argv[3]); /* check call_modprobe() */ | |
68 | kfree(info->argv); | |
69 | } | |
70 | ||
3e63a93b ON |
71 | static int call_modprobe(char *module_name, int wait) |
72 | { | |
f634460c | 73 | struct subprocess_info *info; |
3e63a93b ON |
74 | static char *envp[] = { |
75 | "HOME=/", | |
76 | "TERM=linux", | |
77 | "PATH=/sbin:/usr/sbin:/bin:/usr/bin", | |
78 | NULL | |
79 | }; | |
80 | ||
1cc684ab ON |
81 | char **argv = kmalloc(sizeof(char *[5]), GFP_KERNEL); |
82 | if (!argv) | |
83 | goto out; | |
84 | ||
85 | module_name = kstrdup(module_name, GFP_KERNEL); | |
86 | if (!module_name) | |
87 | goto free_argv; | |
88 | ||
89 | argv[0] = modprobe_path; | |
90 | argv[1] = "-q"; | |
91 | argv[2] = "--"; | |
92 | argv[3] = module_name; /* check free_modprobe_argv() */ | |
93 | argv[4] = NULL; | |
3e63a93b | 94 | |
f634460c LDM |
95 | info = call_usermodehelper_setup(modprobe_path, argv, envp, GFP_KERNEL, |
96 | NULL, free_modprobe_argv, NULL); | |
97 | if (!info) | |
98 | goto free_module_name; | |
99 | ||
100 | return call_usermodehelper_exec(info, wait | UMH_KILLABLE); | |
101 | ||
102 | free_module_name: | |
103 | kfree(module_name); | |
1cc684ab ON |
104 | free_argv: |
105 | kfree(argv); | |
106 | out: | |
107 | return -ENOMEM; | |
3e63a93b ON |
108 | } |
109 | ||
1da177e4 | 110 | /** |
acae0515 AV |
111 | * __request_module - try to load a kernel module |
112 | * @wait: wait (or not) for the operation to complete | |
bd4207c9 RD |
113 | * @fmt: printf style format string for the name of the module |
114 | * @...: arguments as specified in the format string | |
1da177e4 LT |
115 | * |
116 | * Load a module using the user mode module loader. The function returns | |
60b61a6f N |
117 | * zero on success or a negative errno code or positive exit code from |
118 | * "modprobe" on failure. Note that a successful module load does not mean | |
119 | * the module did not then unload and exit on an error of its own. Callers | |
120 | * must check that the service they requested is now available not blindly | |
121 | * invoke it. | |
1da177e4 LT |
122 | * |
123 | * If module auto-loading support is disabled then this function | |
124 | * becomes a no-operation. | |
125 | */ | |
acae0515 | 126 | int __request_module(bool wait, const char *fmt, ...) |
1da177e4 LT |
127 | { |
128 | va_list args; | |
129 | char module_name[MODULE_NAME_LEN]; | |
130 | unsigned int max_modprobes; | |
131 | int ret; | |
1da177e4 LT |
132 | static atomic_t kmod_concurrent = ATOMIC_INIT(0); |
133 | #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ | |
134 | static int kmod_loop_msg; | |
135 | ||
0fdff3ec TH |
136 | /* |
137 | * We don't allow synchronous module loading from async. Module | |
138 | * init may invoke async_synchronize_full() which will end up | |
139 | * waiting for this task which already is waiting for the module | |
140 | * loading to complete, leading to a deadlock. | |
141 | */ | |
142 | WARN_ON_ONCE(wait && current_is_async()); | |
143 | ||
7f57cfa4 ON |
144 | if (!modprobe_path[0]) |
145 | return 0; | |
146 | ||
1da177e4 LT |
147 | va_start(args, fmt); |
148 | ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); | |
149 | va_end(args); | |
150 | if (ret >= MODULE_NAME_LEN) | |
151 | return -ENAMETOOLONG; | |
152 | ||
dd8dbf2e EP |
153 | ret = security_kernel_module_request(module_name); |
154 | if (ret) | |
155 | return ret; | |
156 | ||
1da177e4 LT |
157 | /* If modprobe needs a service that is in a module, we get a recursive |
158 | * loop. Limit the number of running kmod threads to max_threads/2 or | |
159 | * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method | |
160 | * would be to run the parents of this process, counting how many times | |
161 | * kmod was invoked. That would mean accessing the internals of the | |
162 | * process tables to get the command line, proc_pid_cmdline is static | |
163 | * and it is not worth changing the proc code just to handle this case. | |
164 | * KAO. | |
165 | * | |
166 | * "trace the ppid" is simple, but will fail if someone's | |
167 | * parent exits. I think this is as good as it gets. --RR | |
168 | */ | |
169 | max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT); | |
170 | atomic_inc(&kmod_concurrent); | |
171 | if (atomic_read(&kmod_concurrent) > max_modprobes) { | |
172 | /* We may be blaming an innocent here, but unlikely */ | |
37252db6 | 173 | if (kmod_loop_msg < 5) { |
1da177e4 LT |
174 | printk(KERN_ERR |
175 | "request_module: runaway loop modprobe %s\n", | |
176 | module_name); | |
37252db6 JK |
177 | kmod_loop_msg++; |
178 | } | |
1da177e4 LT |
179 | atomic_dec(&kmod_concurrent); |
180 | return -ENOMEM; | |
181 | } | |
182 | ||
7ead8b83 LZ |
183 | trace_module_request(module_name, wait, _RET_IP_); |
184 | ||
3e63a93b | 185 | ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC); |
a06a4dc3 | 186 | |
1da177e4 LT |
187 | atomic_dec(&kmod_concurrent); |
188 | return ret; | |
189 | } | |
acae0515 | 190 | EXPORT_SYMBOL(__request_module); |
118a9069 | 191 | #endif /* CONFIG_MODULES */ |
1da177e4 | 192 | |
0baf2a4d MS |
193 | static void call_usermodehelper_freeinfo(struct subprocess_info *info) |
194 | { | |
195 | if (info->cleanup) | |
196 | (*info->cleanup)(info); | |
197 | kfree(info); | |
198 | } | |
199 | ||
200 | static void umh_complete(struct subprocess_info *sub_info) | |
201 | { | |
202 | struct completion *comp = xchg(&sub_info->complete, NULL); | |
203 | /* | |
204 | * See call_usermodehelper_exec(). If xchg() returns NULL | |
205 | * we own sub_info, the UMH_KILLABLE caller has gone away | |
206 | * or the caller used UMH_NO_WAIT. | |
207 | */ | |
208 | if (comp) | |
209 | complete(comp); | |
210 | else | |
211 | call_usermodehelper_freeinfo(sub_info); | |
212 | } | |
213 | ||
1da177e4 LT |
214 | /* |
215 | * This is the task which runs the usermode application | |
216 | */ | |
217 | static int ____call_usermodehelper(void *data) | |
218 | { | |
219 | struct subprocess_info *sub_info = data; | |
17f60a7d | 220 | struct cred *new; |
1da177e4 LT |
221 | int retval; |
222 | ||
1da177e4 LT |
223 | spin_lock_irq(¤t->sighand->siglock); |
224 | flush_signal_handlers(current, 1); | |
1da177e4 LT |
225 | spin_unlock_irq(¤t->sighand->siglock); |
226 | ||
227 | /* We can run anywhere, unlike our parent keventd(). */ | |
1a2142af | 228 | set_cpus_allowed_ptr(current, cpu_all_mask); |
1da177e4 | 229 | |
b73a7e76 JE |
230 | /* |
231 | * Our parent is keventd, which runs with elevated scheduling priority. | |
232 | * Avoid propagating that into the userspace child. | |
233 | */ | |
234 | set_user_nice(current, 0); | |
235 | ||
17f60a7d EP |
236 | retval = -ENOMEM; |
237 | new = prepare_kernel_cred(current); | |
238 | if (!new) | |
0baf2a4d | 239 | goto out; |
17f60a7d EP |
240 | |
241 | spin_lock(&umh_sysctl_lock); | |
242 | new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset); | |
243 | new->cap_inheritable = cap_intersect(usermodehelper_inheritable, | |
244 | new->cap_inheritable); | |
245 | spin_unlock(&umh_sysctl_lock); | |
246 | ||
87966996 DH |
247 | if (sub_info->init) { |
248 | retval = sub_info->init(sub_info, new); | |
249 | if (retval) { | |
250 | abort_creds(new); | |
0baf2a4d | 251 | goto out; |
87966996 DH |
252 | } |
253 | } | |
254 | ||
17f60a7d EP |
255 | commit_creds(new); |
256 | ||
c4ad8f98 | 257 | retval = do_execve(getname_kernel(sub_info->path), |
ae903caa AV |
258 | (const char __user *const __user *)sub_info->argv, |
259 | (const char __user *const __user *)sub_info->envp); | |
0baf2a4d MS |
260 | out: |
261 | sub_info->retval = retval; | |
262 | /* wait_for_helper() will call umh_complete if UHM_WAIT_PROC. */ | |
7117bc88 | 263 | if (!(sub_info->wait & UMH_WAIT_PROC)) |
0baf2a4d | 264 | umh_complete(sub_info); |
a74fb73c AV |
265 | if (!retval) |
266 | return 0; | |
fb45550d | 267 | do_exit(0); |
1da177e4 LT |
268 | } |
269 | ||
270 | /* Keventd can't block, but this (a child) can. */ | |
271 | static int wait_for_helper(void *data) | |
272 | { | |
273 | struct subprocess_info *sub_info = data; | |
274 | pid_t pid; | |
1da177e4 | 275 | |
7d642242 | 276 | /* If SIGCLD is ignored sys_wait4 won't populate the status. */ |
76e0a6f4 | 277 | kernel_sigaction(SIGCHLD, SIG_DFL); |
1da177e4 LT |
278 | pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD); |
279 | if (pid < 0) { | |
280 | sub_info->retval = pid; | |
281 | } else { | |
7d642242 | 282 | int ret = -ECHILD; |
1da177e4 LT |
283 | /* |
284 | * Normally it is bogus to call wait4() from in-kernel because | |
285 | * wait4() wants to write the exit code to a userspace address. | |
286 | * But wait_for_helper() always runs as keventd, and put_user() | |
287 | * to a kernel address works OK for kernel threads, due to their | |
288 | * having an mm_segment_t which spans the entire address space. | |
289 | * | |
290 | * Thus the __user pointer cast is valid here. | |
291 | */ | |
111dbe0c BS |
292 | sys_wait4(pid, (int __user *)&ret, 0, NULL); |
293 | ||
294 | /* | |
295 | * If ret is 0, either ____call_usermodehelper failed and the | |
296 | * real error code is already in sub_info->retval or | |
297 | * sub_info->retval is 0 anyway, so don't mess with it then. | |
298 | */ | |
299 | if (ret) | |
300 | sub_info->retval = ret; | |
1da177e4 LT |
301 | } |
302 | ||
b3449922 | 303 | umh_complete(sub_info); |
fb45550d | 304 | do_exit(0); |
1da177e4 LT |
305 | } |
306 | ||
307 | /* This is run by khelper thread */ | |
65f27f38 | 308 | static void __call_usermodehelper(struct work_struct *work) |
1da177e4 | 309 | { |
65f27f38 DH |
310 | struct subprocess_info *sub_info = |
311 | container_of(work, struct subprocess_info, work); | |
d47419cd | 312 | pid_t pid; |
1da177e4 | 313 | |
7117bc88 | 314 | if (sub_info->wait & UMH_WAIT_PROC) |
1da177e4 LT |
315 | pid = kernel_thread(wait_for_helper, sub_info, |
316 | CLONE_FS | CLONE_FILES | SIGCHLD); | |
7f6def9f ON |
317 | else |
318 | pid = kernel_thread(____call_usermodehelper, sub_info, | |
319 | SIGCHLD); | |
1da177e4 | 320 | |
0baf2a4d MS |
321 | if (pid < 0) { |
322 | sub_info->retval = pid; | |
b3449922 | 323 | umh_complete(sub_info); |
86313c48 | 324 | } |
1da177e4 LT |
325 | } |
326 | ||
ccd4b65a RW |
327 | /* |
328 | * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY | |
329 | * (used for preventing user land processes from being created after the user | |
330 | * land has been frozen during a system-wide hibernation or suspend operation). | |
b298d289 | 331 | * Should always be manipulated under umhelper_sem acquired for write. |
ccd4b65a | 332 | */ |
247bc037 | 333 | static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED; |
ccd4b65a RW |
334 | |
335 | /* Number of helpers running */ | |
336 | static atomic_t running_helpers = ATOMIC_INIT(0); | |
337 | ||
338 | /* | |
5307427a | 339 | * Wait queue head used by usermodehelper_disable() to wait for all running |
ccd4b65a RW |
340 | * helpers to finish. |
341 | */ | |
342 | static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); | |
343 | ||
9b78c1da RW |
344 | /* |
345 | * Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled | |
346 | * to become 'false'. | |
347 | */ | |
348 | static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq); | |
349 | ||
ccd4b65a RW |
350 | /* |
351 | * Time to wait for running_helpers to become zero before the setting of | |
5307427a | 352 | * usermodehelper_disabled in usermodehelper_disable() fails |
ccd4b65a RW |
353 | */ |
354 | #define RUNNING_HELPERS_TIMEOUT (5 * HZ) | |
355 | ||
fe2e39d8 | 356 | int usermodehelper_read_trylock(void) |
b298d289 | 357 | { |
247bc037 | 358 | DEFINE_WAIT(wait); |
fe2e39d8 RW |
359 | int ret = 0; |
360 | ||
b298d289 | 361 | down_read(&umhelper_sem); |
247bc037 RW |
362 | for (;;) { |
363 | prepare_to_wait(&usermodehelper_disabled_waitq, &wait, | |
364 | TASK_INTERRUPTIBLE); | |
365 | if (!usermodehelper_disabled) | |
366 | break; | |
367 | ||
368 | if (usermodehelper_disabled == UMH_DISABLED) | |
369 | ret = -EAGAIN; | |
370 | ||
fe2e39d8 | 371 | up_read(&umhelper_sem); |
247bc037 RW |
372 | |
373 | if (ret) | |
374 | break; | |
375 | ||
376 | schedule(); | |
377 | try_to_freeze(); | |
378 | ||
379 | down_read(&umhelper_sem); | |
fe2e39d8 | 380 | } |
247bc037 | 381 | finish_wait(&usermodehelper_disabled_waitq, &wait); |
fe2e39d8 | 382 | return ret; |
b298d289 | 383 | } |
fe2e39d8 | 384 | EXPORT_SYMBOL_GPL(usermodehelper_read_trylock); |
b298d289 | 385 | |
9b78c1da RW |
386 | long usermodehelper_read_lock_wait(long timeout) |
387 | { | |
388 | DEFINE_WAIT(wait); | |
389 | ||
390 | if (timeout < 0) | |
391 | return -EINVAL; | |
392 | ||
393 | down_read(&umhelper_sem); | |
394 | for (;;) { | |
395 | prepare_to_wait(&usermodehelper_disabled_waitq, &wait, | |
396 | TASK_UNINTERRUPTIBLE); | |
397 | if (!usermodehelper_disabled) | |
398 | break; | |
399 | ||
400 | up_read(&umhelper_sem); | |
401 | ||
402 | timeout = schedule_timeout(timeout); | |
403 | if (!timeout) | |
404 | break; | |
405 | ||
406 | down_read(&umhelper_sem); | |
407 | } | |
408 | finish_wait(&usermodehelper_disabled_waitq, &wait); | |
409 | return timeout; | |
410 | } | |
411 | EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait); | |
412 | ||
fe2e39d8 | 413 | void usermodehelper_read_unlock(void) |
b298d289 SB |
414 | { |
415 | up_read(&umhelper_sem); | |
416 | } | |
fe2e39d8 | 417 | EXPORT_SYMBOL_GPL(usermodehelper_read_unlock); |
b298d289 | 418 | |
9b78c1da | 419 | /** |
247bc037 | 420 | * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled. |
9b3c98cd | 421 | * @depth: New value to assign to usermodehelper_disabled. |
247bc037 RW |
422 | * |
423 | * Change the value of usermodehelper_disabled (under umhelper_sem locked for | |
424 | * writing) and wakeup tasks waiting for it to change. | |
9b78c1da | 425 | */ |
247bc037 | 426 | void __usermodehelper_set_disable_depth(enum umh_disable_depth depth) |
9b78c1da RW |
427 | { |
428 | down_write(&umhelper_sem); | |
247bc037 | 429 | usermodehelper_disabled = depth; |
9b78c1da RW |
430 | wake_up(&usermodehelper_disabled_waitq); |
431 | up_write(&umhelper_sem); | |
432 | } | |
433 | ||
1bfcf130 | 434 | /** |
247bc037 RW |
435 | * __usermodehelper_disable - Prevent new helpers from being started. |
436 | * @depth: New value to assign to usermodehelper_disabled. | |
437 | * | |
438 | * Set usermodehelper_disabled to @depth and wait for running helpers to exit. | |
1bfcf130 | 439 | */ |
247bc037 | 440 | int __usermodehelper_disable(enum umh_disable_depth depth) |
8cdd4936 | 441 | { |
ccd4b65a RW |
442 | long retval; |
443 | ||
247bc037 RW |
444 | if (!depth) |
445 | return -EINVAL; | |
446 | ||
b298d289 | 447 | down_write(&umhelper_sem); |
247bc037 | 448 | usermodehelper_disabled = depth; |
b298d289 SB |
449 | up_write(&umhelper_sem); |
450 | ||
1bfcf130 RW |
451 | /* |
452 | * From now on call_usermodehelper_exec() won't start any new | |
453 | * helpers, so it is sufficient if running_helpers turns out to | |
454 | * be zero at one point (it may be increased later, but that | |
455 | * doesn't matter). | |
456 | */ | |
457 | retval = wait_event_timeout(running_helpers_waitq, | |
ccd4b65a RW |
458 | atomic_read(&running_helpers) == 0, |
459 | RUNNING_HELPERS_TIMEOUT); | |
1bfcf130 RW |
460 | if (retval) |
461 | return 0; | |
8cdd4936 | 462 | |
247bc037 | 463 | __usermodehelper_set_disable_depth(UMH_ENABLED); |
1bfcf130 RW |
464 | return -EAGAIN; |
465 | } | |
466 | ||
ccd4b65a RW |
467 | static void helper_lock(void) |
468 | { | |
469 | atomic_inc(&running_helpers); | |
4e857c58 | 470 | smp_mb__after_atomic(); |
ccd4b65a RW |
471 | } |
472 | ||
473 | static void helper_unlock(void) | |
474 | { | |
475 | if (atomic_dec_and_test(&running_helpers)) | |
476 | wake_up(&running_helpers_waitq); | |
477 | } | |
ccd4b65a | 478 | |
1da177e4 | 479 | /** |
0ab4dc92 | 480 | * call_usermodehelper_setup - prepare to call a usermode helper |
61df47c8 RD |
481 | * @path: path to usermode executable |
482 | * @argv: arg vector for process | |
483 | * @envp: environment for process | |
ac331d15 | 484 | * @gfp_mask: gfp mask for memory allocation |
938e4b22 LDM |
485 | * @cleanup: a cleanup function |
486 | * @init: an init function | |
487 | * @data: arbitrary context sensitive data | |
0ab4dc92 | 488 | * |
61df47c8 | 489 | * Returns either %NULL on allocation failure, or a subprocess_info |
0ab4dc92 JF |
490 | * structure. This should be passed to call_usermodehelper_exec to |
491 | * exec the process and free the structure. | |
938e4b22 LDM |
492 | * |
493 | * The init function is used to customize the helper process prior to | |
494 | * exec. A non-zero return code causes the process to error out, exit, | |
495 | * and return the failure to the calling process | |
496 | * | |
497 | * The cleanup function is just before ethe subprocess_info is about to | |
498 | * be freed. This can be used for freeing the argv and envp. The | |
499 | * Function must be runnable in either a process context or the | |
500 | * context in which call_usermodehelper_exec is called. | |
0ab4dc92 | 501 | */ |
ac331d15 | 502 | struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, |
938e4b22 LDM |
503 | char **envp, gfp_t gfp_mask, |
504 | int (*init)(struct subprocess_info *info, struct cred *new), | |
505 | void (*cleanup)(struct subprocess_info *info), | |
506 | void *data) | |
0ab4dc92 JF |
507 | { |
508 | struct subprocess_info *sub_info; | |
ac331d15 | 509 | sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); |
0ab4dc92 JF |
510 | if (!sub_info) |
511 | goto out; | |
512 | ||
513 | INIT_WORK(&sub_info->work, __call_usermodehelper); | |
514 | sub_info->path = path; | |
515 | sub_info->argv = argv; | |
516 | sub_info->envp = envp; | |
938e4b22 LDM |
517 | |
518 | sub_info->cleanup = cleanup; | |
519 | sub_info->init = init; | |
520 | sub_info->data = data; | |
0ab4dc92 JF |
521 | out: |
522 | return sub_info; | |
523 | } | |
938e4b22 | 524 | EXPORT_SYMBOL(call_usermodehelper_setup); |
0ab4dc92 | 525 | |
0ab4dc92 JF |
526 | /** |
527 | * call_usermodehelper_exec - start a usermode application | |
528 | * @sub_info: information about the subprocessa | |
1da177e4 | 529 | * @wait: wait for the application to finish and return status. |
66e5b7e1 LDM |
530 | * when UMH_NO_WAIT don't wait at all, but you get no useful error back |
531 | * when the program couldn't be exec'ed. This makes it safe to call | |
a98f0dd3 | 532 | * from interrupt context. |
1da177e4 LT |
533 | * |
534 | * Runs a user-space application. The application is started | |
535 | * asynchronously if wait is not set, and runs as a child of keventd. | |
536 | * (ie. it runs with full root capabilities). | |
1da177e4 | 537 | */ |
9d944ef3 | 538 | int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) |
1da177e4 | 539 | { |
60be6b9a | 540 | DECLARE_COMPLETION_ONSTACK(done); |
78468033 | 541 | int retval = 0; |
1da177e4 | 542 | |
4c1c7be9 TH |
543 | if (!sub_info->path) { |
544 | call_usermodehelper_freeinfo(sub_info); | |
545 | return -EINVAL; | |
546 | } | |
ccd4b65a | 547 | helper_lock(); |
8cdd4936 | 548 | if (!khelper_wq || usermodehelper_disabled) { |
0ab4dc92 JF |
549 | retval = -EBUSY; |
550 | goto out; | |
551 | } | |
0baf2a4d MS |
552 | /* |
553 | * Set the completion pointer only if there is a waiter. | |
554 | * This makes it possible to use umh_complete to free | |
555 | * the data structure in case of UMH_NO_WAIT. | |
556 | */ | |
557 | sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done; | |
a98f0dd3 AK |
558 | sub_info->wait = wait; |
559 | ||
560 | queue_work(khelper_wq, &sub_info->work); | |
78468033 NC |
561 | if (wait == UMH_NO_WAIT) /* task has freed sub_info */ |
562 | goto unlock; | |
d0bd587a ON |
563 | |
564 | if (wait & UMH_KILLABLE) { | |
565 | retval = wait_for_completion_killable(&done); | |
566 | if (!retval) | |
567 | goto wait_done; | |
568 | ||
569 | /* umh_complete() will see NULL and free sub_info */ | |
570 | if (xchg(&sub_info->complete, NULL)) | |
571 | goto unlock; | |
572 | /* fallthrough, umh_complete() was already called */ | |
573 | } | |
574 | ||
1da177e4 | 575 | wait_for_completion(&done); |
d0bd587a | 576 | wait_done: |
a98f0dd3 | 577 | retval = sub_info->retval; |
78468033 | 578 | out: |
0ab4dc92 | 579 | call_usermodehelper_freeinfo(sub_info); |
78468033 | 580 | unlock: |
ccd4b65a | 581 | helper_unlock(); |
a98f0dd3 | 582 | return retval; |
1da177e4 | 583 | } |
938e4b22 | 584 | EXPORT_SYMBOL(call_usermodehelper_exec); |
785042f2 | 585 | |
66e5b7e1 LDM |
586 | /** |
587 | * call_usermodehelper() - prepare and start a usermode application | |
588 | * @path: path to usermode executable | |
589 | * @argv: arg vector for process | |
590 | * @envp: environment for process | |
591 | * @wait: wait for the application to finish and return status. | |
592 | * when UMH_NO_WAIT don't wait at all, but you get no useful error back | |
593 | * when the program couldn't be exec'ed. This makes it safe to call | |
594 | * from interrupt context. | |
595 | * | |
596 | * This function is the equivalent to use call_usermodehelper_setup() and | |
597 | * call_usermodehelper_exec(). | |
79c743dd | 598 | */ |
66e5b7e1 | 599 | int call_usermodehelper(char *path, char **argv, char **envp, int wait) |
785042f2 BH |
600 | { |
601 | struct subprocess_info *info; | |
602 | gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL; | |
603 | ||
938e4b22 | 604 | info = call_usermodehelper_setup(path, argv, envp, gfp_mask, |
66e5b7e1 | 605 | NULL, NULL, NULL); |
785042f2 BH |
606 | if (info == NULL) |
607 | return -ENOMEM; | |
608 | ||
785042f2 BH |
609 | return call_usermodehelper_exec(info, wait); |
610 | } | |
66e5b7e1 | 611 | EXPORT_SYMBOL(call_usermodehelper); |
1da177e4 | 612 | |
17f60a7d EP |
613 | static int proc_cap_handler(struct ctl_table *table, int write, |
614 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
615 | { | |
616 | struct ctl_table t; | |
617 | unsigned long cap_array[_KERNEL_CAPABILITY_U32S]; | |
618 | kernel_cap_t new_cap; | |
619 | int err, i; | |
620 | ||
621 | if (write && (!capable(CAP_SETPCAP) || | |
622 | !capable(CAP_SYS_MODULE))) | |
623 | return -EPERM; | |
624 | ||
625 | /* | |
626 | * convert from the global kernel_cap_t to the ulong array to print to | |
627 | * userspace if this is a read. | |
628 | */ | |
629 | spin_lock(&umh_sysctl_lock); | |
630 | for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) { | |
631 | if (table->data == CAP_BSET) | |
632 | cap_array[i] = usermodehelper_bset.cap[i]; | |
633 | else if (table->data == CAP_PI) | |
634 | cap_array[i] = usermodehelper_inheritable.cap[i]; | |
635 | else | |
636 | BUG(); | |
637 | } | |
638 | spin_unlock(&umh_sysctl_lock); | |
639 | ||
640 | t = *table; | |
641 | t.data = &cap_array; | |
642 | ||
643 | /* | |
644 | * actually read or write and array of ulongs from userspace. Remember | |
645 | * these are least significant 32 bits first | |
646 | */ | |
647 | err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos); | |
648 | if (err < 0) | |
649 | return err; | |
650 | ||
651 | /* | |
652 | * convert from the sysctl array of ulongs to the kernel_cap_t | |
653 | * internal representation | |
654 | */ | |
655 | for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) | |
656 | new_cap.cap[i] = cap_array[i]; | |
657 | ||
658 | /* | |
659 | * Drop everything not in the new_cap (but don't add things) | |
660 | */ | |
661 | spin_lock(&umh_sysctl_lock); | |
662 | if (write) { | |
663 | if (table->data == CAP_BSET) | |
664 | usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap); | |
665 | if (table->data == CAP_PI) | |
666 | usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap); | |
667 | } | |
668 | spin_unlock(&umh_sysctl_lock); | |
669 | ||
670 | return 0; | |
671 | } | |
672 | ||
673 | struct ctl_table usermodehelper_table[] = { | |
674 | { | |
675 | .procname = "bset", | |
676 | .data = CAP_BSET, | |
677 | .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), | |
678 | .mode = 0600, | |
679 | .proc_handler = proc_cap_handler, | |
680 | }, | |
681 | { | |
682 | .procname = "inheritable", | |
683 | .data = CAP_PI, | |
684 | .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), | |
685 | .mode = 0600, | |
686 | .proc_handler = proc_cap_handler, | |
687 | }, | |
688 | { } | |
689 | }; | |
690 | ||
1da177e4 LT |
691 | void __init usermodehelper_init(void) |
692 | { | |
693 | khelper_wq = create_singlethread_workqueue("khelper"); | |
694 | BUG_ON(!khelper_wq); | |
695 | } |