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