milnetv2.c

milnetv2.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define BUFFER_SIZE 512

void print_image()
{
    char buffer[BUFFER_SIZE];
    FILE* fp = fopen("banner.ascii","r");
    if(fp != NULL)
    {
        while((fgets(buffer,BUFFER_SIZE,fp)) != NULL)
            printf("%s", buffer);
        fclose(fp);    
    }else
    {
        printf("[!] Error file not found: login_image.ascii\n");
        exit(-1);    
    }
}

void read_flag(char* flag)
{
    FILE* fd = fopen(".passwd","r");
    if(fd == NULL)
    {
        printf("[!] Error file not found: .passwd\n");
        exit(-1);
    }
    else
    {    
        fgets(flag,32,fd);
        fclose(fd);
    }
}

int main(int argc,char** argv)
{
    int logged;
    char username[32];
    char password[32];
    char flag[32];
    char* p;

    setvbuf(stdout, NULL, _IONBF, 0);
    setvbuf(stdin, NULL, _IONBF, 0);
    
    read_flag(flag);
    print_image();
    
    while(1)
    {
        memset(username,'\0',32);
        memset(password,'\0',32);
        
        printf("Enter username : ");
        fgets(username,32,stdin);
        printf("Enter password : ");
        fgets(password,32,stdin);
        
        p = strstr(username,"\n");
        if(p != NULL) *p = 0;
        p = strstr(password,"\n");
        if(p != NULL) *p = 0;
        
        if(strcmp(username,"exit") == 0) 
            exit(0);
        
        logged = strcmp(password,flag);
        printf("[LOG] username:%s\n",username);
        printf("[LOG] entered password:%s\n",password);
        printf("[LOG] logged:%d\n",logged);
        if(logged == 0)
        {
            printf("######  Welcome %s\n",username);
            execl("/bin/sh","/bin/sh",NULL);
        }
        else
            printf("----------------------[ ACCESS DENIED ]--------------------------\n");
    }
}