#!/bin/bash
#
# Author: Damian Myerscough
# Date: 19/09/2007
# Purpose: Download the latest kernel source, ChangeLog and signature file
# 	   and sort them into the appropriate directories.
#
########################### INSTALLATION NOTES #############################
#                          ** GPG IS REQUIRED **                           #
# Download the kernels gpg key (http://www.kernel.org/signature.html)      #
############################################################################

export PATH=/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games

# Path to store the kernel source
ROOT_DIR=/home/damian/Desktop/kernel

# Proxy Settings. If you are not using a proxy comment this out.
Proxy=10.0.0.4:81
export http_proxy=$Proxy ftp_proxy=$Proxy HTTP_PROXY=$Proxy FTP_PROXY=$Proxy

# Email addresses to be seperated with a comma (,)
ADMIN=Damian.Myerscough@example.net


# Available kernels
URL0=http://www.kernel.org/pub/linux/kernel/v2.6
URL1=http://www.kernel.org/pub/linux/kernel/v2.4
URL2=http://www.kernel.org/pub/linux/kernel/v2.2

# Latest kernel banner ** DON'T MODIFY **
KERNEL_BANNER=http://www.kernel.org/kdist/finger_banner

TEMP_FILE=$( mktemp )

# Check to make sure we get the kernel banner before attempting anything
if [ $( wget -q $KERNEL_BANNER -O $TEMP_FILE ; echo $? ) -eq 1 ]; then
	echo "[-] Unable to receive kernel banner" 
	exit -1;
fi;

# Check to make sure the kernel banner was saved successfully
if [ -e $TEMP_FILE ]; then

	# Check to see if the kernel tree exsits
	if [ ! -d $ROOT_DIR ]; then
		mkdir $ROOT_DIR
	fi;

	# Get the latest kernels 2.6, 2.4 and 2.2
	LATEST_KERNEL=$( grep -i "The latest stable version" $TEMP_FILE | awk -F: '{ print $2 }' | sed -e 's/ //g' )
	LATEST_24_KERNEL=$( grep -i "The latest 2.4" $TEMP_FILE | awk -F: '{ print $2 }' | sed -e 's/ //g' )
	LATEST_22_KERNEL=$( grep -i "The latest 2.2" $TEMP_FILE | awk -F: '{ print $2 }' | sed -e 's/ //g' )

	# Create the appropriate directories
	if [ ! -d $ROOT_DIR"/"$LATEST_KERNEL ]; then
		mkdir $ROOT_DIR"/"$LATEST_KERNEL
	
		# Check to see if we have the latest version of the 2.6.x kernel
	        if [ ! -e $ROOT_DIR"/"$LATEST_KERNEL"/linux-"$LATEST_KERNEL".tar.bz2" -o ! -e $ROOT_DIR"/"$LATEST_KERNEL"/ChangeLog-"$LATEST_KERNEL ]; then
        	        # Download the actual source code
                	wget -q $URL0"/linux-"$LATEST_KERNEL".tar.bz2" -O $ROOT_DIR"/"$LATEST_KERNEL"/linux-"$LATEST_KERNEL".tar.bz2"

                	# Download the Change logs
                	wget -q $URL0"/ChangeLog-"$LATEST_KERNEL -O $ROOT_DIR"/"$LATEST_KERNEL"/ChangeLog-"$LATEST_KERNEL

			# Download source signature file
			wget -q $URL0"/linux-"$LATEST_KERNEL".tar.bz2.sign" -O $ROOT_DIR"/"$LATEST_KERNEL"/linux-"$LATEST_KERNEL".tar.bz2.sign"

			if [ $( gpg --verify $ROOT_DIR"/"$LATEST_KERNEL"/linux-"$LATEST_KERNEL".tar.bz2.sign" $ROOT_DIR"/"$LATEST_KERNEL"/linux-"$LATEST_KERNEL".tar.bz2" ; echo $? ) -eq 1 ]; then 
				echo "The" $LATEST_KERNEL " kernel failed against a signature check" | mail $ADMIN -s "** ALERT ** KERNEL $LATEST_KERNEL HAS BEEN TAMPERED WITH ** ALERT **"
				
				# Delete bad source
				rm -rf $ROOT_DIR"/"$LATEST_KERNEL
			else
				echo "New" $LATEST_KERNEL "kernel added, signature successful" | mail $ADMIN -s "New $LATEST_KERNEL kernel downloaded"
			fi;

        	fi;
	fi;

	if [ ! -d $ROOT_DIR"/"$LATEST_24_KERNEL ]; then
		mkdir $ROOT_DIR"/"$LATEST_24_KERNEL

		# Check to see if we have the latest version of the 2.4.x kernel
       		 if [ ! -e $ROOT_DIR"/"$LATEST_24_KERNEL"/linux-"$LATEST_24_KERNEL".tar.bz2" -o ! -e $ROOT_DIR"/"$LATEST_24_KERNEL"/ChangeLog-"$LATEST_24_KERNEL ]; then
                	# Download the actual source code
                	wget -q $URL1"/linux-"$LATEST_24_KERNEL".tar.bz2" -O $ROOT_DIR"/"$LATEST_24_KERNEL"/linux-"$LATEST_24_KERNEL".tar.bz2"
                
               		# Download the Change logs
                	wget -q $URL1"/ChangeLog-"$LATEST_24_KERNEL -O $ROOT_DIR"/"$LATEST_24_KERNEL"/ChangeLog-"$LATEST_24_KERNEL

			# Donload source signature file
			wget -q $URL1"/linux-"$LATEST_24_KERNEL".tar.bz2.sign" -O $ROOT_DIR"/"$LATEST_24_KERNEL"/linux-"$LATEST_24_KERNEL".tar.bz2.sign"
        	
			if [ $( gpg --verify $ROOT_DIR"/"$LATEST_24_KERNEL"/linux-"$LATEST_24_KERNEL".tar.bz2.sign" $ROOT_DIR"/"$LATEST_24_KERNEL"/linux-"$LATEST_24_KERNEL".tar.bz2" ; echo $? ) -eq 1 ]; then
                                echo "The" $LATEST_24_KERNEL " kernel failed against a signature check" | mail $ADMIN -s "** ALERT ** KERNEL $LATEST_24_KERNEL HAS BEEN TAMPERED WITH ** ALERT **"
                        	
				# Delete Bad source
				rm -rf $ROOT_DIR"/"$LATEST_24_KERNEL
			else
                        	echo "New" $LATEST_24_KERNEL "kernel added, signature successful" | mail $ADMIN -s "New $LATEST_24_KERNEL kernel downloaded"
			fi;

		fi;
	fi;

	if [ ! -d $ROOT_DIR"/"$LATEST_22_KERNEL ]; then
		mkdir $ROOT_DIR"/"$LATEST_22_KERNEL

        	# Check to see if we have the latest version of the 2.2.x kernel
        	if [ ! -e $ROOT_DIR"/"$LATEST_22_KERNEL"/linux-"$LATEST_22_KERNEL".tar.bz2" -o ! -e $ROOT_DIR"/"$LATEST_22_KERNEL"/ChangeLog-"$LATEST_22_KERNEL ]; then
                	# Download the actual source code
                	wget -q $URL2"/linux-"$LATEST_22_KERNEL".tar.bz2" -O $ROOT_DIR"/"$LATEST_22_KERNEL"/linux-"$LATEST_22_KERNEL".tar.bz2"
                
                	# Download the change logs
                	wget -q $URL2"/ChangeLog-"$LATEST_22_KERNEL -O $ROOT_DIR"/"$LATEST_22_KERNEL"/ChangeLog-"$LATEST_22_KERNEL

			# Download source signature file
			wget -q $URL2"/linux-"$LATEST_22_KERNEL".tar.bz2" -O $ROOT_DIR"/"$LATEST_22_KERNEL"/linux-"$LATEST_22_KERNEL".tar.bz2.sign"

			if [ $( gpg --verify $ROOT_DIR"/"$LATEST_22_KERNEL"/linux-"$LATEST_22_KERNEL".tar.bz2.sign" $ROOT_DIR"/"$LATEST_22_KERNEL"/linux-"$LATEST_22_KERNEL".tar.bz2" ; echo $? ) -eq 1 ]; then
                                echo "The" $LATEST_22_KERNEL " kernel failed against a signature check" | mail $ADMIN -s "** ALERT ** KERNEL $LATEST_22_KERNEL HAS BEEN TAMPERED WITH ** ALERT **"
                        	
				# Delete bad source
				rm -rf $ROOT_DIR"/"$LATEST_22_KERNEL
			else
                                echo "New" $LATEST_22_KERNEL "kernel added, signature successful" | mail $ADMIN -s "New $LATEST_22_KERNEL kernel downloaded" 
                        fi;			

        	fi;
	fi;
else
	echo "[-] Kernel banner did NOT exist"
	exit -1;
fi;

# Clean up the kernel text file
unlink $TEMP_FILE