Blame view
kernel/kmod.c
19.1 KB
1da177e4c
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 |
/* kmod, the new module loader (replaces kerneld) Kirk Petersen Reorganized not to be a daemon by Adam Richter, with guidance from Greg Zornetzer. Modified to avoid chroot and file sharing problems. Mikael Pettersson Limit the concurrent number of kmod modprobes to catch loops from "modprobe needs a service that is in a module". Keith Owens <kaos@ocs.com.au> December 1999 Unblock all signals when we exec a usermode process. Shuu Yamaguchi <shuu@wondernetworkresources.com> December 2000 call_usermodehelper wait flag, and remove exec_usermodehelper. Rusty Russell <rusty@rustcorp.com.au> Jan 2003 */ |
1da177e4c
|
21 22 23 24 25 |
#include <linux/module.h> #include <linux/sched.h> #include <linux/syscalls.h> #include <linux/unistd.h> #include <linux/kmod.h> |
1da177e4c
|
26 |
#include <linux/slab.h> |
1da177e4c
|
27 |
#include <linux/completion.h> |
17f60a7da
|
28 |
#include <linux/cred.h> |
1da177e4c
|
29 |
#include <linux/file.h> |
9f3acc314
|
30 |
#include <linux/fdtable.h> |
1da177e4c
|
31 32 33 34 35 |
#include <linux/workqueue.h> #include <linux/security.h> #include <linux/mount.h> #include <linux/kernel.h> #include <linux/init.h> |
d025c9db7
|
36 |
#include <linux/resource.h> |
8cdd4936c
|
37 38 |
#include <linux/notifier.h> #include <linux/suspend.h> |
b298d289c
|
39 |
#include <linux/rwsem.h> |
a74fb73c1
|
40 |
#include <linux/ptrace.h> |
0fdff3ec6
|
41 |
#include <linux/async.h> |
7c0f6ba68
|
42 |
#include <linux/uaccess.h> |
1da177e4c
|
43 |
|
7ead8b831
|
44 |
#include <trace/events/module.h> |
1da177e4c
|
45 |
extern int max_threads; |
17f60a7da
|
46 47 48 49 50 51 |
#define CAP_BSET (void *)1 #define CAP_PI (void *)2 static kernel_cap_t usermodehelper_bset = CAP_FULL_SET; static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET; static DEFINE_SPINLOCK(umh_sysctl_lock); |
b298d289c
|
52 |
static DECLARE_RWSEM(umhelper_sem); |
17f60a7da
|
53 |
|
a1ef5adb4
|
54 |
#ifdef CONFIG_MODULES |
1da177e4c
|
55 56 57 58 59 |
/* modprobe_path is set via /proc/sys. */ char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; |
1cc684ab7
|
60 61 62 63 64 |
static void free_modprobe_argv(struct subprocess_info *info) { kfree(info->argv[3]); /* check call_modprobe() */ kfree(info->argv); } |
3e63a93b9
|
65 66 |
static int call_modprobe(char *module_name, int wait) { |
f634460c9
|
67 |
struct subprocess_info *info; |
3e63a93b9
|
68 69 70 71 72 73 |
static char *envp[] = { "HOME=/", "TERM=linux", "PATH=/sbin:/usr/sbin:/bin:/usr/bin", NULL }; |
1cc684ab7
|
74 75 76 77 78 79 80 81 82 83 84 85 86 |
char **argv = kmalloc(sizeof(char *[5]), GFP_KERNEL); if (!argv) goto out; module_name = kstrdup(module_name, GFP_KERNEL); if (!module_name) goto free_argv; argv[0] = modprobe_path; argv[1] = "-q"; argv[2] = "--"; argv[3] = module_name; /* check free_modprobe_argv() */ argv[4] = NULL; |
3e63a93b9
|
87 |
|
f634460c9
|
88 89 90 91 92 93 94 95 96 |
info = call_usermodehelper_setup(modprobe_path, argv, envp, GFP_KERNEL, NULL, free_modprobe_argv, NULL); if (!info) goto free_module_name; return call_usermodehelper_exec(info, wait | UMH_KILLABLE); free_module_name: kfree(module_name); |
1cc684ab7
|
97 98 99 100 |
free_argv: kfree(argv); out: return -ENOMEM; |
3e63a93b9
|
101 |
} |
1da177e4c
|
102 |
/** |
acae05156
|
103 104 |
* __request_module - try to load a kernel module * @wait: wait (or not) for the operation to complete |
bd4207c90
|
105 106 |
* @fmt: printf style format string for the name of the module * @...: arguments as specified in the format string |
1da177e4c
|
107 108 |
* * Load a module using the user mode module loader. The function returns |
60b61a6f4
|
109 110 111 112 113 |
* zero on success or a negative errno code or positive exit code from * "modprobe" on failure. Note that a successful module load does not mean * the module did not then unload and exit on an error of its own. Callers * must check that the service they requested is now available not blindly * invoke it. |
1da177e4c
|
114 115 116 117 |
* * If module auto-loading support is disabled then this function * becomes a no-operation. */ |
acae05156
|
118 |
int __request_module(bool wait, const char *fmt, ...) |
1da177e4c
|
119 120 121 122 123 |
{ va_list args; char module_name[MODULE_NAME_LEN]; unsigned int max_modprobes; int ret; |
1da177e4c
|
124 125 126 |
static atomic_t kmod_concurrent = ATOMIC_INIT(0); #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ static int kmod_loop_msg; |
0fdff3ec6
|
127 128 129 130 131 132 133 |
/* * We don't allow synchronous module loading from async. Module * init may invoke async_synchronize_full() which will end up * waiting for this task which already is waiting for the module * loading to complete, leading to a deadlock. */ WARN_ON_ONCE(wait && current_is_async()); |
7f57cfa4e
|
134 135 |
if (!modprobe_path[0]) return 0; |
1da177e4c
|
136 137 138 139 140 |
va_start(args, fmt); ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); va_end(args); if (ret >= MODULE_NAME_LEN) return -ENAMETOOLONG; |
dd8dbf2e6
|
141 142 143 |
ret = security_kernel_module_request(module_name); if (ret) return ret; |
1da177e4c
|
144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 |
/* If modprobe needs a service that is in a module, we get a recursive * loop. Limit the number of running kmod threads to max_threads/2 or * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method * would be to run the parents of this process, counting how many times * kmod was invoked. That would mean accessing the internals of the * process tables to get the command line, proc_pid_cmdline is static * and it is not worth changing the proc code just to handle this case. * KAO. * * "trace the ppid" is simple, but will fail if someone's * parent exits. I think this is as good as it gets. --RR */ max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT); atomic_inc(&kmod_concurrent); if (atomic_read(&kmod_concurrent) > max_modprobes) { /* We may be blaming an innocent here, but unlikely */ |
37252db6a
|
160 |
if (kmod_loop_msg < 5) { |
1da177e4c
|
161 162 163 164 |
printk(KERN_ERR "request_module: runaway loop modprobe %s ", module_name); |
37252db6a
|
165 166 |
kmod_loop_msg++; } |
1da177e4c
|
167 168 169 |
atomic_dec(&kmod_concurrent); return -ENOMEM; } |
7ead8b831
|
170 |
trace_module_request(module_name, wait, _RET_IP_); |
3e63a93b9
|
171 |
ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC); |
a06a4dc3a
|
172 |
|
1da177e4c
|
173 174 175 |
atomic_dec(&kmod_concurrent); return ret; } |
acae05156
|
176 |
EXPORT_SYMBOL(__request_module); |
118a9069f
|
177 |
#endif /* CONFIG_MODULES */ |
1da177e4c
|
178 |
|
0baf2a4db
|
179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 |
static void call_usermodehelper_freeinfo(struct subprocess_info *info) { if (info->cleanup) (*info->cleanup)(info); kfree(info); } static void umh_complete(struct subprocess_info *sub_info) { struct completion *comp = xchg(&sub_info->complete, NULL); /* * See call_usermodehelper_exec(). If xchg() returns NULL * we own sub_info, the UMH_KILLABLE caller has gone away * or the caller used UMH_NO_WAIT. */ if (comp) complete(comp); else call_usermodehelper_freeinfo(sub_info); } |
1da177e4c
|
199 200 201 |
/* * This is the task which runs the usermode application */ |
b6b50a814
|
202 |
static int call_usermodehelper_exec_async(void *data) |
1da177e4c
|
203 204 |
{ struct subprocess_info *sub_info = data; |
17f60a7da
|
205 |
struct cred *new; |
1da177e4c
|
206 |
int retval; |
1da177e4c
|
207 208 |
spin_lock_irq(¤t->sighand->siglock); flush_signal_handlers(current, 1); |
1da177e4c
|
209 |
spin_unlock_irq(¤t->sighand->siglock); |
b73a7e76c
|
210 |
/* |
90f023030
|
211 |
* Our parent (unbound workqueue) runs with elevated scheduling |
b639e86ba
|
212 |
* priority. Avoid propagating that into the userspace child. |
b73a7e76c
|
213 214 |
*/ set_user_nice(current, 0); |
17f60a7da
|
215 216 217 |
retval = -ENOMEM; new = prepare_kernel_cred(current); if (!new) |
0baf2a4db
|
218 |
goto out; |
17f60a7da
|
219 220 221 222 223 224 |
spin_lock(&umh_sysctl_lock); new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset); new->cap_inheritable = cap_intersect(usermodehelper_inheritable, new->cap_inheritable); spin_unlock(&umh_sysctl_lock); |
879669961
|
225 226 227 228 |
if (sub_info->init) { retval = sub_info->init(sub_info, new); if (retval) { abort_creds(new); |
0baf2a4db
|
229 |
goto out; |
879669961
|
230 231 |
} } |
17f60a7da
|
232 |
commit_creds(new); |
c4ad8f98b
|
233 |
retval = do_execve(getname_kernel(sub_info->path), |
ae903caae
|
234 235 |
(const char __user *const __user *)sub_info->argv, (const char __user *const __user *)sub_info->envp); |
0baf2a4db
|
236 237 |
out: sub_info->retval = retval; |
b6b50a814
|
238 239 240 241 |
/* * call_usermodehelper_exec_sync() will call umh_complete * if UHM_WAIT_PROC. */ |
7117bc888
|
242 |
if (!(sub_info->wait & UMH_WAIT_PROC)) |
0baf2a4db
|
243 |
umh_complete(sub_info); |
a74fb73c1
|
244 245 |
if (!retval) return 0; |
fb45550d7
|
246 |
do_exit(0); |
1da177e4c
|
247 |
} |
bb304a5c6
|
248 249 |
/* Handles UMH_WAIT_PROC. */ static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) |
1da177e4c
|
250 |
{ |
1da177e4c
|
251 |
pid_t pid; |
1da177e4c
|
252 |
|
7d6422421
|
253 |
/* If SIGCLD is ignored sys_wait4 won't populate the status. */ |
76e0a6f40
|
254 |
kernel_sigaction(SIGCHLD, SIG_DFL); |
b6b50a814
|
255 |
pid = kernel_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD); |
1da177e4c
|
256 257 258 |
if (pid < 0) { sub_info->retval = pid; } else { |
7d6422421
|
259 |
int ret = -ECHILD; |
1da177e4c
|
260 261 262 |
/* * Normally it is bogus to call wait4() from in-kernel because * wait4() wants to write the exit code to a userspace address. |
b639e86ba
|
263 |
* But call_usermodehelper_exec_sync() always runs as kernel |
bb304a5c6
|
264 265 266 |
* thread (workqueue) and put_user() to a kernel address works * OK for kernel threads, due to their having an mm_segment_t * which spans the entire address space. |
1da177e4c
|
267 268 269 |
* * Thus the __user pointer cast is valid here. */ |
111dbe0c8
|
270 271 272 |
sys_wait4(pid, (int __user *)&ret, 0, NULL); /* |
b6b50a814
|
273 274 |
* If ret is 0, either call_usermodehelper_exec_async failed and * the real error code is already in sub_info->retval or |
111dbe0c8
|
275 276 277 278 |
* sub_info->retval is 0 anyway, so don't mess with it then. */ if (ret) sub_info->retval = ret; |
1da177e4c
|
279 |
} |
bb304a5c6
|
280 281 |
/* Restore default kernel sig handler */ kernel_sigaction(SIGCHLD, SIG_IGN); |
b34499225
|
282 |
umh_complete(sub_info); |
1da177e4c
|
283 |
} |
b639e86ba
|
284 |
/* |
bb304a5c6
|
285 |
* We need to create the usermodehelper kernel thread from a task that is affine |
90f023030
|
286 287 288 289 290 |
* to an optimized set of CPUs (or nohz housekeeping ones) such that they * inherit a widest affinity irrespective of call_usermodehelper() callers with * possibly reduced affinity (eg: per-cpu workqueues). We don't want * usermodehelper targets to contend a busy CPU. * |
bb304a5c6
|
291 292 |
* Unbound workqueues provide such wide affinity and allow to block on * UMH_WAIT_PROC requests without blocking pending request (up to some limit). |
b639e86ba
|
293 |
* |
90f023030
|
294 295 |
* Besides, workqueues provide the privilege level that caller might not have * to perform the usermodehelper request. |
b639e86ba
|
296 297 |
* */ |
b6b50a814
|
298 |
static void call_usermodehelper_exec_work(struct work_struct *work) |
1da177e4c
|
299 |
{ |
65f27f384
|
300 301 |
struct subprocess_info *sub_info = container_of(work, struct subprocess_info, work); |
1da177e4c
|
302 |
|
bb304a5c6
|
303 304 305 306 |
if (sub_info->wait & UMH_WAIT_PROC) { call_usermodehelper_exec_sync(sub_info); } else { pid_t pid; |
521161397
|
307 308 309 310 311 |
/* * Use CLONE_PARENT to reparent it to kthreadd; we do not * want to pollute current->children, and we need a parent * that always ignores SIGCHLD to ensure auto-reaping. */ |
b6b50a814
|
312 |
pid = kernel_thread(call_usermodehelper_exec_async, sub_info, |
521161397
|
313 |
CLONE_PARENT | SIGCHLD); |
bb304a5c6
|
314 315 316 317 |
if (pid < 0) { sub_info->retval = pid; umh_complete(sub_info); } |
86313c488
|
318 |
} |
1da177e4c
|
319 |
} |
ccd4b65ae
|
320 321 322 323 |
/* * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY * (used for preventing user land processes from being created after the user * land has been frozen during a system-wide hibernation or suspend operation). |
b298d289c
|
324 |
* Should always be manipulated under umhelper_sem acquired for write. |
ccd4b65ae
|
325 |
*/ |
247bc0374
|
326 |
static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED; |
ccd4b65ae
|
327 328 329 330 331 |
/* Number of helpers running */ static atomic_t running_helpers = ATOMIC_INIT(0); /* |
5307427a3
|
332 |
* Wait queue head used by usermodehelper_disable() to wait for all running |
ccd4b65ae
|
333 334 335 336 337 |
* helpers to finish. */ static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); /* |
9b78c1da6
|
338 339 340 341 342 343 |
* Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled * to become 'false'. */ static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq); /* |
ccd4b65ae
|
344 |
* Time to wait for running_helpers to become zero before the setting of |
5307427a3
|
345 |
* usermodehelper_disabled in usermodehelper_disable() fails |
ccd4b65ae
|
346 347 |
*/ #define RUNNING_HELPERS_TIMEOUT (5 * HZ) |
fe2e39d87
|
348 |
int usermodehelper_read_trylock(void) |
b298d289c
|
349 |
{ |
247bc0374
|
350 |
DEFINE_WAIT(wait); |
fe2e39d87
|
351 |
int ret = 0; |
b298d289c
|
352 |
down_read(&umhelper_sem); |
247bc0374
|
353 354 355 356 357 358 359 360 |
for (;;) { prepare_to_wait(&usermodehelper_disabled_waitq, &wait, TASK_INTERRUPTIBLE); if (!usermodehelper_disabled) break; if (usermodehelper_disabled == UMH_DISABLED) ret = -EAGAIN; |
fe2e39d87
|
361 |
up_read(&umhelper_sem); |
247bc0374
|
362 363 364 365 366 367 368 369 |
if (ret) break; schedule(); try_to_freeze(); down_read(&umhelper_sem); |
fe2e39d87
|
370 |
} |
247bc0374
|
371 |
finish_wait(&usermodehelper_disabled_waitq, &wait); |
fe2e39d87
|
372 |
return ret; |
b298d289c
|
373 |
} |
fe2e39d87
|
374 |
EXPORT_SYMBOL_GPL(usermodehelper_read_trylock); |
b298d289c
|
375 |
|
9b78c1da6
|
376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 |
long usermodehelper_read_lock_wait(long timeout) { DEFINE_WAIT(wait); if (timeout < 0) return -EINVAL; down_read(&umhelper_sem); for (;;) { prepare_to_wait(&usermodehelper_disabled_waitq, &wait, TASK_UNINTERRUPTIBLE); if (!usermodehelper_disabled) break; up_read(&umhelper_sem); timeout = schedule_timeout(timeout); if (!timeout) break; down_read(&umhelper_sem); } finish_wait(&usermodehelper_disabled_waitq, &wait); return timeout; } EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait); |
fe2e39d87
|
402 |
void usermodehelper_read_unlock(void) |
b298d289c
|
403 404 405 |
{ up_read(&umhelper_sem); } |
fe2e39d87
|
406 |
EXPORT_SYMBOL_GPL(usermodehelper_read_unlock); |
b298d289c
|
407 |
|
1bfcf1304
|
408 |
/** |
247bc0374
|
409 |
* __usermodehelper_set_disable_depth - Modify usermodehelper_disabled. |
9b3c98cd6
|
410 |
* @depth: New value to assign to usermodehelper_disabled. |
247bc0374
|
411 412 413 |
* * Change the value of usermodehelper_disabled (under umhelper_sem locked for * writing) and wakeup tasks waiting for it to change. |
9b78c1da6
|
414 |
*/ |
247bc0374
|
415 |
void __usermodehelper_set_disable_depth(enum umh_disable_depth depth) |
9b78c1da6
|
416 417 |
{ down_write(&umhelper_sem); |
247bc0374
|
418 |
usermodehelper_disabled = depth; |
9b78c1da6
|
419 420 421 422 423 |
wake_up(&usermodehelper_disabled_waitq); up_write(&umhelper_sem); } /** |
247bc0374
|
424 425 426 427 |
* __usermodehelper_disable - Prevent new helpers from being started. * @depth: New value to assign to usermodehelper_disabled. * * Set usermodehelper_disabled to @depth and wait for running helpers to exit. |
1bfcf1304
|
428 |
*/ |
247bc0374
|
429 |
int __usermodehelper_disable(enum umh_disable_depth depth) |
8cdd4936c
|
430 |
{ |
ccd4b65ae
|
431 |
long retval; |
247bc0374
|
432 433 |
if (!depth) return -EINVAL; |
b298d289c
|
434 |
down_write(&umhelper_sem); |
247bc0374
|
435 |
usermodehelper_disabled = depth; |
b298d289c
|
436 |
up_write(&umhelper_sem); |
1bfcf1304
|
437 438 439 440 441 442 443 |
/* * From now on call_usermodehelper_exec() won't start any new * helpers, so it is sufficient if running_helpers turns out to * be zero at one point (it may be increased later, but that * doesn't matter). */ retval = wait_event_timeout(running_helpers_waitq, |
ccd4b65ae
|
444 445 |
atomic_read(&running_helpers) == 0, RUNNING_HELPERS_TIMEOUT); |
1bfcf1304
|
446 447 |
if (retval) return 0; |
8cdd4936c
|
448 |
|
247bc0374
|
449 |
__usermodehelper_set_disable_depth(UMH_ENABLED); |
1bfcf1304
|
450 451 |
return -EAGAIN; } |
ccd4b65ae
|
452 453 454 |
static void helper_lock(void) { atomic_inc(&running_helpers); |
4e857c58e
|
455 |
smp_mb__after_atomic(); |
ccd4b65ae
|
456 457 458 459 460 461 462 |
} static void helper_unlock(void) { if (atomic_dec_and_test(&running_helpers)) wake_up(&running_helpers_waitq); } |
ccd4b65ae
|
463 |
|
1da177e4c
|
464 |
/** |
0ab4dc922
|
465 |
* call_usermodehelper_setup - prepare to call a usermode helper |
61df47c8d
|
466 467 468 |
* @path: path to usermode executable * @argv: arg vector for process * @envp: environment for process |
ac331d158
|
469 |
* @gfp_mask: gfp mask for memory allocation |
938e4b22e
|
470 471 472 |
* @cleanup: a cleanup function * @init: an init function * @data: arbitrary context sensitive data |
0ab4dc922
|
473 |
* |
61df47c8d
|
474 |
* Returns either %NULL on allocation failure, or a subprocess_info |
0ab4dc922
|
475 476 |
* structure. This should be passed to call_usermodehelper_exec to * exec the process and free the structure. |
938e4b22e
|
477 478 479 480 481 482 483 484 485 |
* * The init function is used to customize the helper process prior to * exec. A non-zero return code causes the process to error out, exit, * and return the failure to the calling process * * The cleanup function is just before ethe subprocess_info is about to * be freed. This can be used for freeing the argv and envp. The * Function must be runnable in either a process context or the * context in which call_usermodehelper_exec is called. |
0ab4dc922
|
486 |
*/ |
ac331d158
|
487 |
struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, |
938e4b22e
|
488 489 490 491 |
char **envp, gfp_t gfp_mask, int (*init)(struct subprocess_info *info, struct cred *new), void (*cleanup)(struct subprocess_info *info), void *data) |
0ab4dc922
|
492 493 |
{ struct subprocess_info *sub_info; |
ac331d158
|
494 |
sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); |
0ab4dc922
|
495 496 |
if (!sub_info) goto out; |
b6b50a814
|
497 |
INIT_WORK(&sub_info->work, call_usermodehelper_exec_work); |
0ab4dc922
|
498 499 500 |
sub_info->path = path; sub_info->argv = argv; sub_info->envp = envp; |
938e4b22e
|
501 502 503 504 |
sub_info->cleanup = cleanup; sub_info->init = init; sub_info->data = data; |
0ab4dc922
|
505 506 507 |
out: return sub_info; } |
938e4b22e
|
508 |
EXPORT_SYMBOL(call_usermodehelper_setup); |
0ab4dc922
|
509 510 |
/** |
0ab4dc922
|
511 512 |
* call_usermodehelper_exec - start a usermode application * @sub_info: information about the subprocessa |
1da177e4c
|
513 |
* @wait: wait for the application to finish and return status. |
66e5b7e19
|
514 515 |
* when UMH_NO_WAIT don't wait at all, but you get no useful error back * when the program couldn't be exec'ed. This makes it safe to call |
a98f0dd34
|
516 |
* from interrupt context. |
1da177e4c
|
517 518 |
* * Runs a user-space application. The application is started |
90f023030
|
519 520 |
* asynchronously if wait is not set, and runs as a child of system workqueues. * (ie. it runs with full root capabilities and optimized affinity). |
1da177e4c
|
521 |
*/ |
9d944ef32
|
522 |
int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) |
1da177e4c
|
523 |
{ |
60be6b9a4
|
524 |
DECLARE_COMPLETION_ONSTACK(done); |
784680336
|
525 |
int retval = 0; |
1da177e4c
|
526 |
|
4c1c7be95
|
527 528 529 530 |
if (!sub_info->path) { call_usermodehelper_freeinfo(sub_info); return -EINVAL; } |
ccd4b65ae
|
531 |
helper_lock(); |
90f023030
|
532 |
if (usermodehelper_disabled) { |
0ab4dc922
|
533 534 535 |
retval = -EBUSY; goto out; } |
0f20784d4
|
536 |
/* |
0baf2a4db
|
537 538 539 540 541 |
* Set the completion pointer only if there is a waiter. * This makes it possible to use umh_complete to free * the data structure in case of UMH_NO_WAIT. */ sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done; |
a98f0dd34
|
542 |
sub_info->wait = wait; |
90f023030
|
543 |
queue_work(system_unbound_wq, &sub_info->work); |
784680336
|
544 545 |
if (wait == UMH_NO_WAIT) /* task has freed sub_info */ goto unlock; |
d0bd587a8
|
546 547 548 549 550 551 552 553 554 555 556 |
if (wait & UMH_KILLABLE) { retval = wait_for_completion_killable(&done); if (!retval) goto wait_done; /* umh_complete() will see NULL and free sub_info */ if (xchg(&sub_info->complete, NULL)) goto unlock; /* fallthrough, umh_complete() was already called */ } |
1da177e4c
|
557 |
wait_for_completion(&done); |
d0bd587a8
|
558 |
wait_done: |
a98f0dd34
|
559 |
retval = sub_info->retval; |
784680336
|
560 |
out: |
0ab4dc922
|
561 |
call_usermodehelper_freeinfo(sub_info); |
784680336
|
562 |
unlock: |
ccd4b65ae
|
563 |
helper_unlock(); |
a98f0dd34
|
564 |
return retval; |
1da177e4c
|
565 |
} |
938e4b22e
|
566 |
EXPORT_SYMBOL(call_usermodehelper_exec); |
785042f2e
|
567 |
|
66e5b7e19
|
568 569 570 571 572 573 574 575 576 577 578 579 |
/** * call_usermodehelper() - prepare and start a usermode application * @path: path to usermode executable * @argv: arg vector for process * @envp: environment for process * @wait: wait for the application to finish and return status. * when UMH_NO_WAIT don't wait at all, but you get no useful error back * when the program couldn't be exec'ed. This makes it safe to call * from interrupt context. * * This function is the equivalent to use call_usermodehelper_setup() and * call_usermodehelper_exec(). |
79c743dd1
|
580 |
*/ |
66e5b7e19
|
581 |
int call_usermodehelper(char *path, char **argv, char **envp, int wait) |
785042f2e
|
582 583 584 |
{ struct subprocess_info *info; gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL; |
938e4b22e
|
585 |
info = call_usermodehelper_setup(path, argv, envp, gfp_mask, |
66e5b7e19
|
586 |
NULL, NULL, NULL); |
785042f2e
|
587 588 |
if (info == NULL) return -ENOMEM; |
785042f2e
|
589 590 |
return call_usermodehelper_exec(info, wait); } |
66e5b7e19
|
591 |
EXPORT_SYMBOL(call_usermodehelper); |
1da177e4c
|
592 |
|
17f60a7da
|
593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 |
static int proc_cap_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table t; unsigned long cap_array[_KERNEL_CAPABILITY_U32S]; kernel_cap_t new_cap; int err, i; if (write && (!capable(CAP_SETPCAP) || !capable(CAP_SYS_MODULE))) return -EPERM; /* * convert from the global kernel_cap_t to the ulong array to print to * userspace if this is a read. */ spin_lock(&umh_sysctl_lock); for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) { if (table->data == CAP_BSET) cap_array[i] = usermodehelper_bset.cap[i]; else if (table->data == CAP_PI) cap_array[i] = usermodehelper_inheritable.cap[i]; else BUG(); } spin_unlock(&umh_sysctl_lock); t = *table; t.data = &cap_array; /* * actually read or write and array of ulongs from userspace. Remember * these are least significant 32 bits first */ err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos); if (err < 0) return err; /* * convert from the sysctl array of ulongs to the kernel_cap_t * internal representation */ for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) new_cap.cap[i] = cap_array[i]; /* * Drop everything not in the new_cap (but don't add things) */ spin_lock(&umh_sysctl_lock); if (write) { if (table->data == CAP_BSET) usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap); if (table->data == CAP_PI) usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap); } spin_unlock(&umh_sysctl_lock); return 0; } struct ctl_table usermodehelper_table[] = { { .procname = "bset", .data = CAP_BSET, .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), .mode = 0600, .proc_handler = proc_cap_handler, }, { .procname = "inheritable", .data = CAP_PI, .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), .mode = 0600, .proc_handler = proc_cap_handler, }, { } }; |