1 // SPDX-License-Identifier: GPL-2.0-only
3  * umh - the kernel usermode helper
41 	if (info->cleanup)  in call_usermodehelper_freeinfo()
42 		(*info->cleanup)(info);  in call_usermodehelper_freeinfo()
48 	struct completion *comp = xchg(&sub_info->complete, NULL);  in umh_complete()
69 	spin_lock_irq(&current->sighand->siglock);  in call_usermodehelper_exec_async()
71 	spin_unlock_irq(&current->sighand->siglock);  in call_usermodehelper_exec_async()
79 	current->fs->umask = 0022;  in call_usermodehelper_exec_async()
87 	retval = -ENOMEM;  in call_usermodehelper_exec_async()
93 	new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset);  in call_usermodehelper_exec_async()
94 	new->cap_inheritable = cap_intersect(usermodehelper_inheritable,  in call_usermodehelper_exec_async()
95 					     new->cap_inheritable);  in call_usermodehelper_exec_async()
98 	if (sub_info->init) {  in call_usermodehelper_exec_async()
99 		retval = sub_info->init(sub_info, new);  in call_usermodehelper_exec_async()
109 	retval = kernel_execve(sub_info->path,  in call_usermodehelper_exec_async()
110 			       (const char *const *)sub_info->argv,  in call_usermodehelper_exec_async()
111 			       (const char *const *)sub_info->envp);  in call_usermodehelper_exec_async()
113 	sub_info->retval = retval;  in call_usermodehelper_exec_async()
118 	if (!(sub_info->wait & UMH_WAIT_PROC))  in call_usermodehelper_exec_async()
134 		sub_info->retval = pid;  in call_usermodehelper_exec_sync()
136 		kernel_wait(pid, &sub_info->retval);  in call_usermodehelper_exec_sync()
147  * possibly reduced affinity (eg: per-cpu workqueues). We don't want
162 	if (sub_info->wait & UMH_WAIT_PROC) {  in call_usermodehelper_exec_work()
168 		 * want to pollute current->children, and we need a parent  in call_usermodehelper_exec_work()
169 		 * that always ignores SIGCHLD to ensure auto-reaping.  in call_usermodehelper_exec_work()
174 			sub_info->retval = pid;  in call_usermodehelper_exec_work()
181  * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
183  * land has been frozen during a system-wide hibernation or suspend operation).
192  * Wait queue head used by usermodehelper_disable() to wait for all running
198  * Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled
204  * Time to wait for running_helpers to become zero before the setting of
211 	DEFINE_WAIT(wait);  in usermodehelper_read_trylock()
216 		prepare_to_wait(&usermodehelper_disabled_waitq, &wait,  in usermodehelper_read_trylock()
222 			ret = -EAGAIN;  in usermodehelper_read_trylock()
234 	finish_wait(&usermodehelper_disabled_waitq, &wait);  in usermodehelper_read_trylock()
241 	DEFINE_WAIT(wait);  in usermodehelper_read_lock_wait()
244 		return -EINVAL;  in usermodehelper_read_lock_wait()
248 		prepare_to_wait(&usermodehelper_disabled_waitq, &wait,  in usermodehelper_read_lock_wait()
261 	finish_wait(&usermodehelper_disabled_waitq, &wait);  in usermodehelper_read_lock_wait()
273  * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled.
288  * __usermodehelper_disable - Prevent new helpers from being started.
291  * Set usermodehelper_disabled to @depth and wait for running helpers to exit.
298 		return -EINVAL;  in __usermodehelper_disable()
317 	return -EAGAIN;  in __usermodehelper_disable()
333  * call_usermodehelper_setup - prepare to call a usermode helper
344  * exec the process and free the structure.
347  * exec.  A non-zero return code causes the process to error out, exit,
366 	INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);  in call_usermodehelper_setup()
369 	sub_info->path = CONFIG_STATIC_USERMODEHELPER_PATH;  in call_usermodehelper_setup()
371 	sub_info->path = path;  in call_usermodehelper_setup()
373 	sub_info->argv = argv;  in call_usermodehelper_setup()
374 	sub_info->envp = envp;  in call_usermodehelper_setup()
376 	sub_info->cleanup = cleanup;  in call_usermodehelper_setup()
377 	sub_info->init = init;  in call_usermodehelper_setup()
378 	sub_info->data = data;  in call_usermodehelper_setup()
385  * call_usermodehelper_exec - start a usermode application
387  * @wait: wait for the application to finish and return status.
388  *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
392  * Runs a user-space application.  The application is started
393  * asynchronously if wait is not set, and runs as a child of system workqueues.
397  * all. You can't rely on sub_info->{init,cleanup} being called even for
398  * UMH_WAIT_* wait modes as STATIC_USERMODEHELPER_PATH="" turns all helpers
399  * into a successful no-op.
401 int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)  in call_usermodehelper_exec()  argument
407 	if (!sub_info->path) {  in call_usermodehelper_exec()
409 		return -EINVAL;  in call_usermodehelper_exec()
413 		retval = -EBUSY;  in call_usermodehelper_exec()
418 	 * If there is no binary for us to call, then just return and get out of  in call_usermodehelper_exec()
419 	 * here.  This allows us to set STATIC_USERMODEHELPER_PATH to "" and  in call_usermodehelper_exec()
422 	if (strlen(sub_info->path) == 0)  in call_usermodehelper_exec()
427 	 * This makes it possible to use umh_complete to free  in call_usermodehelper_exec()
430 	sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done;  in call_usermodehelper_exec()
431 	sub_info->wait = wait;  in call_usermodehelper_exec()
433 	queue_work(system_unbound_wq, &sub_info->work);  in call_usermodehelper_exec()
434 	if (wait == UMH_NO_WAIT)	/* task has freed sub_info */  in call_usermodehelper_exec()
437 	if (wait & UMH_FREEZABLE)  in call_usermodehelper_exec()
440 	if (wait & UMH_KILLABLE) {  in call_usermodehelper_exec()
445 		/* umh_complete() will see NULL and free sub_info */  in call_usermodehelper_exec()
446 		if (xchg(&sub_info->complete, NULL))  in call_usermodehelper_exec()
450 		 * fallthrough; in case of -ERESTARTSYS now do uninterruptible  in call_usermodehelper_exec()
460 	retval = sub_info->retval;  in call_usermodehelper_exec()
470  * call_usermodehelper() - prepare and start a usermode application
474  * @wait: wait for the application to finish and return status.
475  *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
482 int call_usermodehelper(const char *path, char **argv, char **envp, int wait)  in call_usermodehelper()  argument
485 	gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;  in call_usermodehelper()
490 		return -ENOMEM;  in call_usermodehelper()
492 	return call_usermodehelper_exec(info, wait);  in call_usermodehelper()
507 		return -EPERM;  in proc_cap_handler()
513 	 * Legacy format: capabilities are exposed as two 32-bit values  in proc_cap_handler()
515 	cap = table->data;  in proc_cap_handler()
517 	cap_array[0] = (u32) cap->val;  in proc_cap_handler()
518 	cap_array[1] = cap->val >> 32;  in proc_cap_handler()