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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> |
1da177e4 LT |
40 | #include <asm/uaccess.h> |
41 | ||
7ead8b83 LZ |
42 | #include <trace/events/module.h> |
43 | ||
1da177e4 LT |
44 | extern int max_threads; |
45 | ||
46 | static struct workqueue_struct *khelper_wq; | |
47 | ||
17f60a7d EP |
48 | #define CAP_BSET (void *)1 |
49 | #define CAP_PI (void *)2 | |
50 | ||
51 | static kernel_cap_t usermodehelper_bset = CAP_FULL_SET; | |
52 | static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET; | |
53 | static DEFINE_SPINLOCK(umh_sysctl_lock); | |
b298d289 | 54 | static DECLARE_RWSEM(umhelper_sem); |
17f60a7d | 55 | |
a1ef5adb | 56 | #ifdef CONFIG_MODULES |
1da177e4 LT |
57 | |
58 | /* | |
59 | modprobe_path is set via /proc/sys. | |
60 | */ | |
61 | char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; | |
62 | ||
1cc684ab ON |
63 | static void free_modprobe_argv(struct subprocess_info *info) |
64 | { | |
65 | kfree(info->argv[3]); /* check call_modprobe() */ | |
66 | kfree(info->argv); | |
67 | } | |
68 | ||
3e63a93b ON |
69 | static int call_modprobe(char *module_name, int wait) |
70 | { | |
71 | static char *envp[] = { | |
72 | "HOME=/", | |
73 | "TERM=linux", | |
74 | "PATH=/sbin:/usr/sbin:/bin:/usr/bin", | |
75 | NULL | |
76 | }; | |
77 | ||
1cc684ab ON |
78 | char **argv = kmalloc(sizeof(char *[5]), GFP_KERNEL); |
79 | if (!argv) | |
80 | goto out; | |
81 | ||
82 | module_name = kstrdup(module_name, GFP_KERNEL); | |
83 | if (!module_name) | |
84 | goto free_argv; | |
85 | ||
86 | argv[0] = modprobe_path; | |
87 | argv[1] = "-q"; | |
88 | argv[2] = "--"; | |
89 | argv[3] = module_name; /* check free_modprobe_argv() */ | |
90 | argv[4] = NULL; | |
3e63a93b ON |
91 | |
92 | return call_usermodehelper_fns(modprobe_path, argv, envp, | |
1cc684ab ON |
93 | wait | UMH_KILLABLE, NULL, free_modprobe_argv, NULL); |
94 | free_argv: | |
95 | kfree(argv); | |
96 | out: | |
97 | return -ENOMEM; | |
3e63a93b ON |
98 | } |
99 | ||
1da177e4 | 100 | /** |
acae0515 AV |
101 | * __request_module - try to load a kernel module |
102 | * @wait: wait (or not) for the operation to complete | |
bd4207c9 RD |
103 | * @fmt: printf style format string for the name of the module |
104 | * @...: arguments as specified in the format string | |
1da177e4 LT |
105 | * |
106 | * Load a module using the user mode module loader. The function returns | |
107 | * zero on success or a negative errno code on failure. Note that a | |
108 | * successful module load does not mean the module did not then unload | |
109 | * and exit on an error of its own. Callers must check that the service | |
110 | * they requested is now available not blindly invoke it. | |
111 | * | |
112 | * If module auto-loading support is disabled then this function | |
113 | * becomes a no-operation. | |
114 | */ | |
acae0515 | 115 | int __request_module(bool wait, const char *fmt, ...) |
1da177e4 LT |
116 | { |
117 | va_list args; | |
118 | char module_name[MODULE_NAME_LEN]; | |
119 | unsigned int max_modprobes; | |
120 | int ret; | |
1da177e4 LT |
121 | static atomic_t kmod_concurrent = ATOMIC_INIT(0); |
122 | #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ | |
123 | static int kmod_loop_msg; | |
124 | ||
125 | va_start(args, fmt); | |
126 | ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); | |
127 | va_end(args); | |
128 | if (ret >= MODULE_NAME_LEN) | |
129 | return -ENAMETOOLONG; | |
130 | ||
dd8dbf2e EP |
131 | ret = security_kernel_module_request(module_name); |
132 | if (ret) | |
133 | return ret; | |
134 | ||
1da177e4 LT |
135 | /* If modprobe needs a service that is in a module, we get a recursive |
136 | * loop. Limit the number of running kmod threads to max_threads/2 or | |
137 | * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method | |
138 | * would be to run the parents of this process, counting how many times | |
139 | * kmod was invoked. That would mean accessing the internals of the | |
140 | * process tables to get the command line, proc_pid_cmdline is static | |
141 | * and it is not worth changing the proc code just to handle this case. | |
142 | * KAO. | |
143 | * | |
144 | * "trace the ppid" is simple, but will fail if someone's | |
145 | * parent exits. I think this is as good as it gets. --RR | |
146 | */ | |
147 | max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT); | |
148 | atomic_inc(&kmod_concurrent); | |
149 | if (atomic_read(&kmod_concurrent) > max_modprobes) { | |
150 | /* We may be blaming an innocent here, but unlikely */ | |
37252db6 | 151 | if (kmod_loop_msg < 5) { |
1da177e4 LT |
152 | printk(KERN_ERR |
153 | "request_module: runaway loop modprobe %s\n", | |
154 | module_name); | |
37252db6 JK |
155 | kmod_loop_msg++; |
156 | } | |
1da177e4 LT |
157 | atomic_dec(&kmod_concurrent); |
158 | return -ENOMEM; | |
159 | } | |
160 | ||
7ead8b83 LZ |
161 | trace_module_request(module_name, wait, _RET_IP_); |
162 | ||
3e63a93b | 163 | ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC); |
a06a4dc3 | 164 | |
1da177e4 LT |
165 | atomic_dec(&kmod_concurrent); |
166 | return ret; | |
167 | } | |
acae0515 | 168 | EXPORT_SYMBOL(__request_module); |
118a9069 | 169 | #endif /* CONFIG_MODULES */ |
1da177e4 | 170 | |
1da177e4 LT |
171 | /* |
172 | * This is the task which runs the usermode application | |
173 | */ | |
174 | static int ____call_usermodehelper(void *data) | |
175 | { | |
176 | struct subprocess_info *sub_info = data; | |
17f60a7d | 177 | struct cred *new; |
1da177e4 LT |
178 | int retval; |
179 | ||
1da177e4 LT |
180 | spin_lock_irq(¤t->sighand->siglock); |
181 | flush_signal_handlers(current, 1); | |
1da177e4 LT |
182 | spin_unlock_irq(¤t->sighand->siglock); |
183 | ||
184 | /* We can run anywhere, unlike our parent keventd(). */ | |
1a2142af | 185 | set_cpus_allowed_ptr(current, cpu_all_mask); |
1da177e4 | 186 | |
b73a7e76 JE |
187 | /* |
188 | * Our parent is keventd, which runs with elevated scheduling priority. | |
189 | * Avoid propagating that into the userspace child. | |
190 | */ | |
191 | set_user_nice(current, 0); | |
192 | ||
17f60a7d EP |
193 | retval = -ENOMEM; |
194 | new = prepare_kernel_cred(current); | |
195 | if (!new) | |
196 | goto fail; | |
197 | ||
198 | spin_lock(&umh_sysctl_lock); | |
199 | new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset); | |
200 | new->cap_inheritable = cap_intersect(usermodehelper_inheritable, | |
201 | new->cap_inheritable); | |
202 | spin_unlock(&umh_sysctl_lock); | |
203 | ||
87966996 DH |
204 | if (sub_info->init) { |
205 | retval = sub_info->init(sub_info, new); | |
206 | if (retval) { | |
207 | abort_creds(new); | |
208 | goto fail; | |
209 | } | |
210 | } | |
211 | ||
17f60a7d EP |
212 | commit_creds(new); |
213 | ||
d7627467 DH |
214 | retval = kernel_execve(sub_info->path, |
215 | (const char *const *)sub_info->argv, | |
216 | (const char *const *)sub_info->envp); | |
1da177e4 LT |
217 | |
218 | /* Exec failed? */ | |
a06a4dc3 | 219 | fail: |
1da177e4 | 220 | sub_info->retval = retval; |
5b9bd473 | 221 | return 0; |
1da177e4 LT |
222 | } |
223 | ||
0ab4dc92 JF |
224 | void call_usermodehelper_freeinfo(struct subprocess_info *info) |
225 | { | |
226 | if (info->cleanup) | |
a06a4dc3 | 227 | (*info->cleanup)(info); |
0ab4dc92 JF |
228 | kfree(info); |
229 | } | |
230 | EXPORT_SYMBOL(call_usermodehelper_freeinfo); | |
231 | ||
b3449922 ON |
232 | static void umh_complete(struct subprocess_info *sub_info) |
233 | { | |
d0bd587a ON |
234 | struct completion *comp = xchg(&sub_info->complete, NULL); |
235 | /* | |
236 | * See call_usermodehelper_exec(). If xchg() returns NULL | |
237 | * we own sub_info, the UMH_KILLABLE caller has gone away. | |
238 | */ | |
239 | if (comp) | |
240 | complete(comp); | |
241 | else | |
242 | call_usermodehelper_freeinfo(sub_info); | |
b3449922 ON |
243 | } |
244 | ||
1da177e4 LT |
245 | /* Keventd can't block, but this (a child) can. */ |
246 | static int wait_for_helper(void *data) | |
247 | { | |
248 | struct subprocess_info *sub_info = data; | |
249 | pid_t pid; | |
1da177e4 | 250 | |
7d642242 ON |
251 | /* If SIGCLD is ignored sys_wait4 won't populate the status. */ |
252 | spin_lock_irq(¤t->sighand->siglock); | |
253 | current->sighand->action[SIGCHLD-1].sa.sa_handler = SIG_DFL; | |
254 | spin_unlock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
255 | |
256 | pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD); | |
257 | if (pid < 0) { | |
258 | sub_info->retval = pid; | |
259 | } else { | |
7d642242 | 260 | int ret = -ECHILD; |
1da177e4 LT |
261 | /* |
262 | * Normally it is bogus to call wait4() from in-kernel because | |
263 | * wait4() wants to write the exit code to a userspace address. | |
264 | * But wait_for_helper() always runs as keventd, and put_user() | |
265 | * to a kernel address works OK for kernel threads, due to their | |
266 | * having an mm_segment_t which spans the entire address space. | |
267 | * | |
268 | * Thus the __user pointer cast is valid here. | |
269 | */ | |
111dbe0c BS |
270 | sys_wait4(pid, (int __user *)&ret, 0, NULL); |
271 | ||
272 | /* | |
273 | * If ret is 0, either ____call_usermodehelper failed and the | |
274 | * real error code is already in sub_info->retval or | |
275 | * sub_info->retval is 0 anyway, so don't mess with it then. | |
276 | */ | |
277 | if (ret) | |
278 | sub_info->retval = ret; | |
1da177e4 LT |
279 | } |
280 | ||
b3449922 | 281 | umh_complete(sub_info); |
1da177e4 LT |
282 | return 0; |
283 | } | |
284 | ||
285 | /* This is run by khelper thread */ | |
65f27f38 | 286 | static void __call_usermodehelper(struct work_struct *work) |
1da177e4 | 287 | { |
65f27f38 DH |
288 | struct subprocess_info *sub_info = |
289 | container_of(work, struct subprocess_info, work); | |
9d944ef3 | 290 | int wait = sub_info->wait & ~UMH_KILLABLE; |
d47419cd | 291 | pid_t pid; |
1da177e4 LT |
292 | |
293 | /* CLONE_VFORK: wait until the usermode helper has execve'd | |
294 | * successfully We need the data structures to stay around | |
295 | * until that is done. */ | |
d47419cd | 296 | if (wait == UMH_WAIT_PROC) |
1da177e4 LT |
297 | pid = kernel_thread(wait_for_helper, sub_info, |
298 | CLONE_FS | CLONE_FILES | SIGCHLD); | |
299 | else | |
300 | pid = kernel_thread(____call_usermodehelper, sub_info, | |
301 | CLONE_VFORK | SIGCHLD); | |
302 | ||
86313c48 JF |
303 | switch (wait) { |
304 | case UMH_NO_WAIT: | |
d47419cd | 305 | call_usermodehelper_freeinfo(sub_info); |
86313c48 | 306 | break; |
a98f0dd3 | 307 | |
86313c48 JF |
308 | case UMH_WAIT_PROC: |
309 | if (pid > 0) | |
310 | break; | |
86313c48 | 311 | /* FALLTHROUGH */ |
86313c48 | 312 | case UMH_WAIT_EXEC: |
04b1c384 ON |
313 | if (pid < 0) |
314 | sub_info->retval = pid; | |
b3449922 | 315 | umh_complete(sub_info); |
86313c48 | 316 | } |
1da177e4 LT |
317 | } |
318 | ||
ccd4b65a RW |
319 | /* |
320 | * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY | |
321 | * (used for preventing user land processes from being created after the user | |
322 | * land has been frozen during a system-wide hibernation or suspend operation). | |
b298d289 | 323 | * Should always be manipulated under umhelper_sem acquired for write. |
ccd4b65a | 324 | */ |
288d5abe | 325 | static int usermodehelper_disabled = 1; |
ccd4b65a RW |
326 | |
327 | /* Number of helpers running */ | |
328 | static atomic_t running_helpers = ATOMIC_INIT(0); | |
329 | ||
330 | /* | |
5307427a | 331 | * Wait queue head used by usermodehelper_disable() to wait for all running |
ccd4b65a RW |
332 | * helpers to finish. |
333 | */ | |
334 | static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); | |
335 | ||
336 | /* | |
337 | * Time to wait for running_helpers to become zero before the setting of | |
5307427a | 338 | * usermodehelper_disabled in usermodehelper_disable() fails |
ccd4b65a RW |
339 | */ |
340 | #define RUNNING_HELPERS_TIMEOUT (5 * HZ) | |
341 | ||
b298d289 SB |
342 | void read_lock_usermodehelper(void) |
343 | { | |
344 | down_read(&umhelper_sem); | |
345 | } | |
346 | EXPORT_SYMBOL_GPL(read_lock_usermodehelper); | |
347 | ||
348 | void read_unlock_usermodehelper(void) | |
349 | { | |
350 | up_read(&umhelper_sem); | |
351 | } | |
352 | EXPORT_SYMBOL_GPL(read_unlock_usermodehelper); | |
353 | ||
1bfcf130 RW |
354 | /** |
355 | * usermodehelper_disable - prevent new helpers from being started | |
356 | */ | |
357 | int usermodehelper_disable(void) | |
8cdd4936 | 358 | { |
ccd4b65a RW |
359 | long retval; |
360 | ||
b298d289 | 361 | down_write(&umhelper_sem); |
1bfcf130 | 362 | usermodehelper_disabled = 1; |
b298d289 SB |
363 | up_write(&umhelper_sem); |
364 | ||
1bfcf130 RW |
365 | /* |
366 | * From now on call_usermodehelper_exec() won't start any new | |
367 | * helpers, so it is sufficient if running_helpers turns out to | |
368 | * be zero at one point (it may be increased later, but that | |
369 | * doesn't matter). | |
370 | */ | |
371 | retval = wait_event_timeout(running_helpers_waitq, | |
ccd4b65a RW |
372 | atomic_read(&running_helpers) == 0, |
373 | RUNNING_HELPERS_TIMEOUT); | |
1bfcf130 RW |
374 | if (retval) |
375 | return 0; | |
8cdd4936 | 376 | |
b298d289 | 377 | down_write(&umhelper_sem); |
1bfcf130 | 378 | usermodehelper_disabled = 0; |
b298d289 | 379 | up_write(&umhelper_sem); |
1bfcf130 RW |
380 | return -EAGAIN; |
381 | } | |
382 | ||
383 | /** | |
384 | * usermodehelper_enable - allow new helpers to be started again | |
385 | */ | |
386 | void usermodehelper_enable(void) | |
387 | { | |
b298d289 | 388 | down_write(&umhelper_sem); |
1bfcf130 | 389 | usermodehelper_disabled = 0; |
b298d289 | 390 | up_write(&umhelper_sem); |
8cdd4936 RW |
391 | } |
392 | ||
a144c6a6 RW |
393 | /** |
394 | * usermodehelper_is_disabled - check if new helpers are allowed to be started | |
395 | */ | |
396 | bool usermodehelper_is_disabled(void) | |
397 | { | |
398 | return usermodehelper_disabled; | |
399 | } | |
400 | EXPORT_SYMBOL_GPL(usermodehelper_is_disabled); | |
401 | ||
ccd4b65a RW |
402 | static void helper_lock(void) |
403 | { | |
404 | atomic_inc(&running_helpers); | |
405 | smp_mb__after_atomic_inc(); | |
406 | } | |
407 | ||
408 | static void helper_unlock(void) | |
409 | { | |
410 | if (atomic_dec_and_test(&running_helpers)) | |
411 | wake_up(&running_helpers_waitq); | |
412 | } | |
ccd4b65a | 413 | |
1da177e4 | 414 | /** |
0ab4dc92 | 415 | * call_usermodehelper_setup - prepare to call a usermode helper |
61df47c8 RD |
416 | * @path: path to usermode executable |
417 | * @argv: arg vector for process | |
418 | * @envp: environment for process | |
ac331d15 | 419 | * @gfp_mask: gfp mask for memory allocation |
0ab4dc92 | 420 | * |
61df47c8 | 421 | * Returns either %NULL on allocation failure, or a subprocess_info |
0ab4dc92 JF |
422 | * structure. This should be passed to call_usermodehelper_exec to |
423 | * exec the process and free the structure. | |
424 | */ | |
ac331d15 KM |
425 | struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, |
426 | char **envp, gfp_t gfp_mask) | |
0ab4dc92 JF |
427 | { |
428 | struct subprocess_info *sub_info; | |
ac331d15 | 429 | sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); |
0ab4dc92 JF |
430 | if (!sub_info) |
431 | goto out; | |
432 | ||
433 | INIT_WORK(&sub_info->work, __call_usermodehelper); | |
434 | sub_info->path = path; | |
435 | sub_info->argv = argv; | |
436 | sub_info->envp = envp; | |
0ab4dc92 JF |
437 | out: |
438 | return sub_info; | |
439 | } | |
440 | EXPORT_SYMBOL(call_usermodehelper_setup); | |
441 | ||
0ab4dc92 | 442 | /** |
a06a4dc3 | 443 | * call_usermodehelper_setfns - set a cleanup/init function |
0ab4dc92 JF |
444 | * @info: a subprocess_info returned by call_usermodehelper_setup |
445 | * @cleanup: a cleanup function | |
a06a4dc3 NH |
446 | * @init: an init function |
447 | * @data: arbitrary context sensitive data | |
448 | * | |
449 | * The init function is used to customize the helper process prior to | |
450 | * exec. A non-zero return code causes the process to error out, exit, | |
451 | * and return the failure to the calling process | |
0ab4dc92 | 452 | * |
a06a4dc3 | 453 | * The cleanup function is just before ethe subprocess_info is about to |
0ab4dc92 JF |
454 | * be freed. This can be used for freeing the argv and envp. The |
455 | * Function must be runnable in either a process context or the | |
456 | * context in which call_usermodehelper_exec is called. | |
457 | */ | |
a06a4dc3 | 458 | void call_usermodehelper_setfns(struct subprocess_info *info, |
87966996 | 459 | int (*init)(struct subprocess_info *info, struct cred *new), |
a06a4dc3 NH |
460 | void (*cleanup)(struct subprocess_info *info), |
461 | void *data) | |
0ab4dc92 JF |
462 | { |
463 | info->cleanup = cleanup; | |
a06a4dc3 NH |
464 | info->init = init; |
465 | info->data = data; | |
0ab4dc92 | 466 | } |
a06a4dc3 | 467 | EXPORT_SYMBOL(call_usermodehelper_setfns); |
0ab4dc92 | 468 | |
0ab4dc92 JF |
469 | /** |
470 | * call_usermodehelper_exec - start a usermode application | |
471 | * @sub_info: information about the subprocessa | |
1da177e4 | 472 | * @wait: wait for the application to finish and return status. |
a98f0dd3 AK |
473 | * when -1 don't wait at all, but you get no useful error back when |
474 | * the program couldn't be exec'ed. This makes it safe to call | |
475 | * from interrupt context. | |
1da177e4 LT |
476 | * |
477 | * Runs a user-space application. The application is started | |
478 | * asynchronously if wait is not set, and runs as a child of keventd. | |
479 | * (ie. it runs with full root capabilities). | |
1da177e4 | 480 | */ |
9d944ef3 | 481 | int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) |
1da177e4 | 482 | { |
60be6b9a | 483 | DECLARE_COMPLETION_ONSTACK(done); |
78468033 | 484 | int retval = 0; |
1da177e4 | 485 | |
ccd4b65a | 486 | helper_lock(); |
78468033 | 487 | if (sub_info->path[0] == '\0') |
0ab4dc92 | 488 | goto out; |
1da177e4 | 489 | |
8cdd4936 | 490 | if (!khelper_wq || usermodehelper_disabled) { |
0ab4dc92 JF |
491 | retval = -EBUSY; |
492 | goto out; | |
493 | } | |
a98f0dd3 | 494 | |
a98f0dd3 | 495 | sub_info->complete = &done; |
a98f0dd3 AK |
496 | sub_info->wait = wait; |
497 | ||
498 | queue_work(khelper_wq, &sub_info->work); | |
78468033 NC |
499 | if (wait == UMH_NO_WAIT) /* task has freed sub_info */ |
500 | goto unlock; | |
d0bd587a ON |
501 | |
502 | if (wait & UMH_KILLABLE) { | |
503 | retval = wait_for_completion_killable(&done); | |
504 | if (!retval) | |
505 | goto wait_done; | |
506 | ||
507 | /* umh_complete() will see NULL and free sub_info */ | |
508 | if (xchg(&sub_info->complete, NULL)) | |
509 | goto unlock; | |
510 | /* fallthrough, umh_complete() was already called */ | |
511 | } | |
512 | ||
1da177e4 | 513 | wait_for_completion(&done); |
d0bd587a | 514 | wait_done: |
a98f0dd3 | 515 | retval = sub_info->retval; |
78468033 | 516 | out: |
0ab4dc92 | 517 | call_usermodehelper_freeinfo(sub_info); |
78468033 | 518 | unlock: |
ccd4b65a | 519 | helper_unlock(); |
a98f0dd3 | 520 | return retval; |
1da177e4 | 521 | } |
0ab4dc92 | 522 | EXPORT_SYMBOL(call_usermodehelper_exec); |
1da177e4 | 523 | |
17f60a7d EP |
524 | static int proc_cap_handler(struct ctl_table *table, int write, |
525 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
526 | { | |
527 | struct ctl_table t; | |
528 | unsigned long cap_array[_KERNEL_CAPABILITY_U32S]; | |
529 | kernel_cap_t new_cap; | |
530 | int err, i; | |
531 | ||
532 | if (write && (!capable(CAP_SETPCAP) || | |
533 | !capable(CAP_SYS_MODULE))) | |
534 | return -EPERM; | |
535 | ||
536 | /* | |
537 | * convert from the global kernel_cap_t to the ulong array to print to | |
538 | * userspace if this is a read. | |
539 | */ | |
540 | spin_lock(&umh_sysctl_lock); | |
541 | for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) { | |
542 | if (table->data == CAP_BSET) | |
543 | cap_array[i] = usermodehelper_bset.cap[i]; | |
544 | else if (table->data == CAP_PI) | |
545 | cap_array[i] = usermodehelper_inheritable.cap[i]; | |
546 | else | |
547 | BUG(); | |
548 | } | |
549 | spin_unlock(&umh_sysctl_lock); | |
550 | ||
551 | t = *table; | |
552 | t.data = &cap_array; | |
553 | ||
554 | /* | |
555 | * actually read or write and array of ulongs from userspace. Remember | |
556 | * these are least significant 32 bits first | |
557 | */ | |
558 | err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos); | |
559 | if (err < 0) | |
560 | return err; | |
561 | ||
562 | /* | |
563 | * convert from the sysctl array of ulongs to the kernel_cap_t | |
564 | * internal representation | |
565 | */ | |
566 | for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) | |
567 | new_cap.cap[i] = cap_array[i]; | |
568 | ||
569 | /* | |
570 | * Drop everything not in the new_cap (but don't add things) | |
571 | */ | |
572 | spin_lock(&umh_sysctl_lock); | |
573 | if (write) { | |
574 | if (table->data == CAP_BSET) | |
575 | usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap); | |
576 | if (table->data == CAP_PI) | |
577 | usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap); | |
578 | } | |
579 | spin_unlock(&umh_sysctl_lock); | |
580 | ||
581 | return 0; | |
582 | } | |
583 | ||
584 | struct ctl_table usermodehelper_table[] = { | |
585 | { | |
586 | .procname = "bset", | |
587 | .data = CAP_BSET, | |
588 | .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), | |
589 | .mode = 0600, | |
590 | .proc_handler = proc_cap_handler, | |
591 | }, | |
592 | { | |
593 | .procname = "inheritable", | |
594 | .data = CAP_PI, | |
595 | .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), | |
596 | .mode = 0600, | |
597 | .proc_handler = proc_cap_handler, | |
598 | }, | |
599 | { } | |
600 | }; | |
601 | ||
1da177e4 LT |
602 | void __init usermodehelper_init(void) |
603 | { | |
604 | khelper_wq = create_singlethread_workqueue("khelper"); | |
605 | BUG_ON(!khelper_wq); | |
606 | } |