/me on the net!

redlof worm cure

2006-06-19T17:13:00.000+05:30

When RedLof worm was wrecking havoc on my files, and NAV was deleting all my data, i wrote a small utility that removes infected portions from infected files...

Unfortunately, i knew only Java at that time, so sorry if this program sucks.. but it does its job perfectly..


/** Cure for HTML.Redlof.A virus
*   Copyright (C) Anurag
*/

import java.io.*;
import java.util.*;

public class redlof
{

public static void main(String args[])
{
 System.out.println("Virus Repair tool <HTML.Redlof.A>\n");
 if (args.length==0)
 {
  System.out.println("Usage : java redlof [directory]");
  System.exit(0);
 }
 String loc=args[0];
 System.out.println("\n\n ****** Initializing Virus Remover ****** ");
 System.out.println("Searching : "+loc);
 redlof virus=new redlof();
 virus.scanFiles(new File(loc),new Vector(),"htm");
 virus.scanFiles(new File(loc),new Vector(),"html");
 virus.scanFiles(new File(loc),new Vector(),"asp"); 
}

public void scanFiles(File f, Vector htmlList, String fileExtn)
{
         if (f.isDirectory())
  {
      String[] list = f.list();
         if (list != null)
  {
          for (int i = 0; i < list.length; i++)
   {
             scanFiles(new File(f, list[i]), htmlList,fileExtn);
          }
         }
         }
         else
  {
            if (f.getName().toLowerCase().endsWith(fileExtn))
     {
                htmlList.addElement(f.getAbsolutePath());
  openfile(f.getAbsolutePath());
            }
         }
}

void openfile(String filename)
{
 System.out.print("Scanning file : "+filename);
 String content="";
 byte b[];
 long nob;
 try
 {
  RandomAccessFile raf=new RandomAccessFile(filename,"rw");
  nob=raf.length();
  if(nob<11519)
   return ;
  b=new byte[(int)nob];
  System.out.println("  ## Size = "+nob);
  raf.seek(0);
  raf.read(b);
  content=(new String(b));
  checkinfected(content,filename);
  raf.close();
 }
 catch(Exception e)
 {
 }
}

void checkinfected(String src,String filename)
{
 int infected=src.indexOf("vbscript:KJ_start()");
 if (infected==-1)
 {
  return;
 }
 else
 {
  cure(filename);
 }
}

void cure(String filename)
{
 System.out.println("Repairing file : "+filename);
 byte b[];
 long nob;
 try
 {
  RandomAccessFile raf=new RandomAccessFile(filename,"rw");
  nob=raf.length();
  b=new byte[(int)nob];
  raf.setLength(raf.length()-11516);
  raf.close();
 }
 catch(Exception e)
 {
 }
}
}

disk utilization notifications

2006-05-09T16:57:00.000+05:30

Long time back, at HBCSE we were thinking what to do about the /home partition of server which was getting filled upto 90% every now and then. We used to call up the user having extremely large home directory and ask him/her to freeup some disk space..

Obviously not many people followed our advice, and I was thinking of writing a shell script that would automatically send overusage notifications, and free us of some headache.. Lol, i ended up writing a Python script finally. :)

This script is invoked from crontab with root's priveleges.


#!/usr/bin/env python

## Script for sending Disk utilization notifications:
#  Copyright (C) 2004 Anurag <anurag@gnowledge.org>

import os,re,sys,string
import smtplib
import time

tmpfile='/tmp/disk.stat'    # Name of temp file that saves disk stats
mailfile='/tmp/mail.file'   # file used to store email message
lowerlimit='100 MB'         # Maximum size of home directory 
upperlimit='300 MB'         # Maximum threshold size of homes 
uppersizelimit = 300000     # Upper threshold in KiloBytes
todaysdate=time.ctime()


"""
Function for sending email to users
"""
def sendEmail(username,homesize):
    # Composing the email to be sent to users
    # This part is mime header
    wmsg = 'From: HBCSE Server Admin <root@hbcse.tifr.resDOTin>\n'
    wmsg = wmsg+'To: <' + username + '@hbcse.tifr.resDOTin>\n'
    wmsg = wmsg+'Reply-To: HBCSE Server Admin <root@hbcse.tifr.resDOTin>\n'
    wmsg = wmsg+ 'Subject: Warning: Your HBCSE home size\n'
    wmsg = wmsg+ 'Date: '+ todaysdate +'\n'
    # This part is the actual message
    wmsg = wmsg+ '\n\n\nHello '+ username +',\n\n'
    wmsg = wmsg+ 'Currently the size of your home directory on HBCSE server is'+'\n'
    wmsg = wmsg+ 'more than the maximum threshold limit of '+ upperlimit +'\n'
    wmsg = wmsg+ 'Please reduce the size your home directory on HBCSE server so'+'\n'
    wmsg = wmsg+ 'that it can run efficiently.'+'\n\n'
    wmsg = wmsg+ 'For clarifications call 108 or root@hbcse.tifr.resDOTin '+'\n\n\n'
    wmsg = wmsg+ '-- \nHBCSE Server Admin'+'\n'
    # connecting to mail server
    try:
        s=smtplib.SMTP('localhost')
        s.mail('root@hbcse.tifr.resDOTin')
        s.rcpt(username + '@hbcse.tifr.res.in')
        s.data(wmsg)
    except Exception:
        pass

"""
Function for finding over quota directories
"""
def findOverQuotas(tmpfilename):
    ifile = open(tmpfilename,'r')      # open the file containing disk stats
    filecontents = ifile.readlines()   # read it line by line
    for lines in filecontents:
        userdetails=[]
        userdetails = lines.split()    # split the line into "size" and "username" pairs
        homedirsize,serveruser = userdetails
        homedirsize = string.atoi(userdetails[0])
        if (homedirsize > uppersizelimit):
            sendEmail(serveruser,homedirsize)

# Start of main routine
os.system('cd /home;du -s * 2>/dev/null  >  '+tmpfile )
findOverQuotas(tmpfile)

rsync backup script

2006-05-08T19:34:00.000+05:30

We learnt a hard lesson (everyone does).. Always backup your data.. Harddisks have a very bad habit of going br0ke when you most need it. I just made a small shell script that performs rsync and maintains a copy of data on another server.

CC4 and Web are hostnames of 2 remote webservers which are to be backed up. To enable seamless copying of data across servers, we use passwordless ssh logins. For this purpose, i generated a ssh-key pair for root user, wherein the private key was passwordless. And made a copy of /root/.ssh/id_dsa.pub on the remote servers as well.

The shell script for actual backup is as follows. Its being invoked via crontab every sunday afternoon.



#!/bin/bash
## Script Backs up /etc/ and /var/ from CC4 and Web

LOG_FILE=/var/log/hbc-rsync.log     ## Keeps a copy in /var/log

TMP_LOG_FILE=/tmp/hbc-tmp-rsync.log  ## Mails the current session's log
rm $TMP_LOG_FILE

CC4_BACKUP_DIR=/mnt/backup/cc4
WEB_BACKUP_DIR=/mnt/backup/web

CURRENT_DATE=`date`

## Sync /etc/ and /var/ from CC4

echo "Starting Backup of CC4 on : $CURRENT_DATE" >> $TMP_LOG_FILE
rsync -avzlp -e ssh --delete root@cc4:/var/ $CC4_BACKUP_DIR/var/   2>1 1>>$TMP_LOG_FILE
rsync -avzlp -e ssh --delete root@cc4:/etc/ $CC4_BACKUP_DIR/etc/   2>1 1>>$TMP_LOG_FILE

## Sync /etc/ and /var/ from Web
CURRENT_DATE=`date`
echo "Starting Backup of Web on : $CURRENT_DATE" >> $TMP_LOG_FILE
rsync -avzlp -e ssh --delete root@web:/var/ $WEB_BACKUP_DIR/var/     2>1 1>>$TMP_LOG_FILE
rsync -avzlp -e ssh --delete root@web:/etc/ $WEB_BACKUP_DIR/etc/     2>1 1>>$TMP_LOG_FILE
rsync -avzlp -e ssh --delete root@web:/home/ $WEB_BACKUP_DIR/home/   2>1 1>>$TMP_LOG_FILE
##
cat $TMP_LOG_FILE >> $LOG_FILE
cat $TMP_LOG_FILE | mail root@localhost -s  "CC4 rsync results"

hello world!

2006-04-01T14:14:00.000+05:30

mandatory hello world post.. :)