linux-imx

// SPDX-License-Identifier: GPL-2.0-only

/*

 * umh - the kernel usermode helper

 */

#include <linux/module.h>

#include <linux/sched.h>

#include <linux/sched/task.h>

#include <linux/binfmts.h>

#include <linux/syscalls.h>

#include <linux/unistd.h>

#include <linux/kmod.h>

#include <linux/slab.h>

#include <linux/completion.h>

#include <linux/cred.h>

#include <linux/file.h>

#include <linux/fdtable.h>

#include <linux/workqueue.h>

#include <linux/security.h>

#include <linux/mount.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/resource.h>

#include <linux/notifier.h>

#include <linux/suspend.h>

#include <linux/rwsem.h>

#include <linux/ptrace.h>

#include <linux/async.h>

#include <linux/uaccess.h>

#include <linux/shmem_fs.h>

#include <linux/pipe_fs_i.h>

​

#include <trace/events/module.h>

​

#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);

static DECLARE_RWSEM(umhelper_sem);

static LIST_HEAD(umh_list);

static DEFINE_MUTEX(umh_list_lock);

​

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);

}

​

/*

 * This is the task which runs the usermode application

 */

static int call_usermodehelper_exec_async(void *data)

{

    struct subprocess_info *sub_info = data;

    struct cred *new;

    int retval;

​

    spin_lock_irq(&current->sighand->siglock);

    flush_signal_handlers(current, 1);

    spin_unlock_irq(&current->sighand->siglock);

​

    /*

     * Our parent (unbound workqueue) runs with elevated scheduling

     * priority. Avoid propagating that into the userspace child.

     */

    set_user_nice(current, 0);

​

    retval = -ENOMEM;

    new = prepare_kernel_cred(current);

    if (!new)

        goto out;

​

    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);