kapil1024

Basic steps:

Install python3 and pip3

sudo apt update -y
sudo apt install python3 python3-pip git unzip -y

Clone the repo

kapil1024

Network setup

10.1.1.4/24 --> a system connected to bmc system. 10.1.1.5/24 --> bmc system. localhost --> my laptop. Suppose we want to access a service running at UDP port 623 but UDP port 623 is blocked by our firewall and TCP port 80 is unblocked. So we can use nc to create a tunnel using TCP port 80.

Configuration

1. laptop terminal#1:
   • mkfifo /tmp/fifo
   • sudo nc -l -u -p 623 < /tmp/fifo | nc 10.1.1.4 80 > /tmp/fifo

kapil1024

// Modified version of https://gist.github.com/igorgatis/d294fe714a4f523ac3a3
        function hexdump(buffer, blockSize, maxLength) {
          if(typeof buffer === 'string'){
            console.log("buffer is string");
            //do nothing
          }else if(buffer instanceof ArrayBuffer && buffer.byteLength !== undefined){
            console.log("buffer is ArrayBuffer");
            var tlen = buffer.byteLength;
            if (tlen > 65000) tlen = 65000;
            buffer = String.fromCharCode.apply(String, [].slice.call(new Uint8Array(buffer, 0, tlen)));

kapil1024

Project URL https://github.com/novnc/websockify-other

Building websockify

• apt install openssl-dev
• git clone git@github.com:novnc/websockify-other.git websockify
• cd websockify/c
• make
• cp websockify /usr/bin

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Install required packages

apt install -y nbd-server nbd-client apache2 wget samba smbclient cifs-utils tftpd-hpa tftp

Set a variable for local IP (not mandatory)

export LOCAL_IP="192.168.21.2"

HTTPS server

1. Enable SSL module and restart the server
   • a2enmod ssl

• a2ensite default-ssl

kapil1024

1. Check current state of swap swapon -s

2. Turn off the swap swapoff -a

3. Formate a file or block device as swap mkswap /dev/sdX

4. Update fstab to mount this swap devie/file on every boot

kapil1024

/*
 * This program is inspired from following articles -
 * http://www.linux-pam.org/Linux-PAM-html/adg-example.html
 * https://docs.oracle.com/cd/E23824_01/html/819-2145/pam-1.html#pam-20
 * https://man7.org/tlpi/code/online/book/tty/no_echo.c.html
 *
 * Install required packages:
 * $ sudo apt-get install libpam-dev -y
 *
 * Compile using gcc:

kapil1024

#include <stdio.h>
#include <stdlib.h>
#include <systemd/sd-bus.h>

int main(int argc, char *argv[]) {
        sd_bus_error error = SD_BUS_ERROR_NULL;
        sd_bus_message *m = NULL;
        sd_bus *bus = NULL;
        int64_t x, y, z;
        int r;

kapil1024

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/socket.h>
#include <systemd/sd-bus.h>

int fds[2];

#define INT_TO_PTR(integer)   ((void*) (long) ((int)integer))

kapil1024

#include<stdio.h>

// A sample puzzle
int sudoku[9][9] =    { {0,0,0,4,0,0,0,9,0},
                        {0,3,0,0,5,0,0,1,8},
                        {0,0,0,0,0,0,6,0,7},
                        {4,2,0,1,0,3,0,0,6},
                        {0,9,0,0,0,0,0,2,0},
                        {7,0,0,2,0,8,0,4,1},
                        {6,0,4,0,0,0,0,0,0},