Reading config file in C using libconfig

I defined a structure for options in my config file and a pointer to this structure in "config.h" file and I read config file using libconfig and set values in function get_config() that is defined in file "config.c". In main function I initialize pointer to structure and call get_config() function. libconfig works well and prints values of structure's fields correctly but when I print same fields in main functions their values are incorrect!

"config.h"

#include <stdio.h>
#include <stdlib.h>
#include <libconfig.h>

typedef struct
{
    int buffer_size;
    const char * DBusername;
    const char * DBpassword;
}conf;

conf *config;

int get_config();

"config.c"

#include "config.h"


int get_config()
{
    config_t cfg;
    config_setting_t *setting;

    config_init(&cfg);

    /* Read the file. If there is an error, report it and exit. */
    if(! config_read_file(&cfg, "config.cfg"))
    {
        fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg),
            config_error_line(&cfg), config_error_text(&cfg));
        config_destroy(&cfg);
        return(EXIT_FAILURE);
    }

    if(config_lookup_int(&cfg, "buffersize", &config->buffer_size))
        printf("buffersize: %d\n\n", config->buffer_size);
    else
        fprintf(stderr, "No 'buffersize' setting in configuration file.\n");

    if(config_lookup_string(&cfg, "DBusername", &config->DBusername))
        printf("DBusername: %s\n\n", config->DBusername);
    else
        fprintf(stderr, "No 'DBusername' setting in configuration file.\n");

    if(config_lookup_string(&cfg, "DBpassword", &config->DBpassword))
        printf("DBpassword: %s\n\n", config->DBpassword);
    else
        fprintf(stderr, "No 'DBpassword' setting in configuration file.\n");

    config_destroy(&cfg);

    return(EXIT_SUCCESS);

}

"store.c"

int main(){
    config = (conf*) malloc(sizeof(conf));
    if(get_config() == EXIT_FAILURE)
        return 0;

    printf("\n%s", config->DBusername);
    printf("\n%s", config->DBpassword);
    printf("\n%d", config->buffer_size);
}

The problem is because of defining char* in structure. I changed the char* to char[] and the problem is solved! :)