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emerg.c
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emerg.c
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/*
* Copyright (c) 2017, cedric zirtacic (https://github.com/cedriczirtacic)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Gibson nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/moduleparam.h>
#include <linux/keyboard.h>
#include <linux/notifier.h>
#include <linux/version.h>
/* parameters */
static char *phrase;
static char *exec;
module_param(phrase, charp, S_IRUGO);
module_param(exec, charp, S_IRUGO);
/* module vars */
static int matches = 0;
static char *env[] = {
"USER=root",
"HOME=/",
"TERM=linux",
"SHELL=/bin/bash",
"PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin",
NULL
};
static int shell_exec(char *e) {
#ifdef DEBUG
printk(KERN_INFO "executing %s", e);
#endif
matches = 0; //start all over again
struct subprocess_info *info;
char *argv[] = {"/bin/sh", "-c", e, NULL};
#if LINUX_VERSION_CODE > KERNEL_VERSION(4, 0, 0)
info = call_usermodehelper_setup(argv[0], argv, env, GFP_ATOMIC, NULL, NULL, NULL);
#elif
info = call_usermodehelper_setup(argv[0], argv, env, GFP_ATOMIC);
#endif
if (info == NULL){
#ifdef DEBUG
printk(KERN_ERR "error! *info struct is NULL");
#endif
return -ENOMEM;
}
//lets execute
int ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
#ifdef DEBUG
if (ret != 0)
printk(KERN_INFO "return value: %d", ret);
#endif
return ret;
}
int _kb_call(struct notifier_block *nb, unsigned long code, void *p) {
struct keyboard_notifier_param *params = p;
// we've got some key pressed but not pressure
if (code == KBD_POST_KEYSYM && !params->down) {
char p_char = params->value^0xfb00; // clean
if (p_char == *(phrase+matches)) {
if (++matches == strlen(phrase)) // all the keys matched
shell_exec(exec);
return NOTIFY_OK;
}else
// character mismatch, start again
matches = 0;
}
return NOTIFY_OK;
}
static struct notifier_block nblock = {
.notifier_call = _kb_call
};
static int __init emerg_init(void) {
#ifdef DEBUG
printk(KERN_INFO "emerg loaded...");
#endif
if (phrase == NULL || exec == NULL)
return -EINVAL;
register_keyboard_notifier(&nblock);
return 0;
}
static void __exit emerg_exit(void) {
unregister_keyboard_notifier(&nblock);
}
module_init( emerg_init );
module_exit( emerg_exit );
MODULE_LICENSE("GPL");