<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML ><HEAD ><TITLE >Preparing the system</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="Encrypted Root Filesystem HOWTO" HREF="index.html"><LINK REL="PREVIOUS" TITLE="Encrypted Root Filesystem HOWTO" HREF="index.html"><LINK REL="NEXT" TITLE="Creating the encrypted root filesystem" HREF="encrypt-root-filesystem.html"></HEAD ><BODY CLASS="sect1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >Encrypted Root Filesystem HOWTO</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="index.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="encrypt-root-filesystem.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="sect1" ><H1 CLASS="sect1" ><A NAME="preparing-system" ></A >1. Preparing the system</H1 ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="partition-layout" ></A >1.1. Setting up the partition layout</H2 ><P > Your hard disk (hda) should contain at least three partitions: <P ></P ><UL ><LI ><P > hda1: this small unencrypted partition will ask for a password in order to mount the encrypted root filesystem. </P ></LI ><LI ><P > hda2: this partition will contain your encrypted root filesystem; make sure it is large enough. </P ></LI ><LI ><P > hda3: this partition holds the current GNU/Linux system. </P ></LI ></UL > </P ><P > At this point, both hda1 and hda2 are unused. hda3 is where your Linux distribution is currently installed; /usr and /boot must <EM >not</EM > be separated from this partition. </P ><P > Here's an example of what your partition layout might look like: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" ># fdisk -l /dev/hda Disk /dev/hda: 255 heads, 63 sectors, 2432 cylinders Units = cylinders of 16065 * 512 bytes Device Boot Start End Blocks Id System /dev/hda1 1 1 8001 83 Linux /dev/hda2 2 263 2104515 83 Linux /dev/hda3 264 525 2104515 83 Linux /dev/hda4 526 2047 12225465 83 Linux</PRE ></FONT ></TD ></TR ></TABLE > </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="debian-packages" ></A >1.2. Required packages</H2 ><P > If you use Debian, the following packages are mandatory: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >apt-get install gcc make libncurses5-dev patch bzip2 wget</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > To make copy & paste easier, you should also install: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >apt-get install lynx gpm</PRE ></FONT ></TD ></TR ></TABLE > </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="install-kernel-2.4" ></A >1.3. Installing Linux-2.4.29</H2 ><P > There are two main projects which add loopback encryption support in the kernel: cryptoloop and loop-AES. This howto is based on loop-AES, since it features an extremely fast and highly optimized implementation of Rijndael in assembly language, and therefore provides maximum performance if you have an IA-32 (x86) CPU. Besides, there are some <A HREF="http://groups.google.com/groups?selm=1emrG-1Ck-25%40gated-at.bofh.it" TARGET="_top" >security concerns</A > about cryptoloop. </P ><P > First of all, download and unpack the loop-AES package: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >cd /usr/src wget http://loop-aes.sourceforge.net/loop-AES/loop-AES-v3.0b.tar.bz2 tar -xvjf loop-AES-v3.0b.tar.bz2</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > Then you must download and patch the kernel source: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >wget http://ftp.kernel.org/pub/linux/kernel/v2.4/linux-2.4.29.tar.bz2 tar -xvjf linux-2.4.29.tar.bz2 cd linux-2.4.29 rm include/linux/loop.h drivers/block/loop.c patch -Np1 -i ../loop-AES-v3.0b/kernel-2.4.28.diff</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > Setup the keyboard map: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >dumpkeys | loadkeys -m - > drivers/char/defkeymap.c</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > Next, configure your kernel; make sure the following options are set: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >make menuconfig Block devices ---> <*> Loopback device support [*] AES encrypted loop device support (NEW) <*> RAM disk support (4096) Default RAM disk size (NEW) [*] Initial RAM disk (initrd) support File systems ---> <*> Ext3 journalling file system support <*> Second extended fs support (important note: do not enable /dev file system support)</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > Compile the kernel and install it: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >make dep bzImage make modules modules_install cp arch/i386/boot/bzImage /boot/vmlinuz</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > If grub is your bootloader, update /boot/grub/menu.lst or /boot/grub/grub.conf: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >cat > /boot/grub/menu.lst << EOF default 0 timeout 10 color green/black light-green/black title Linux root (hd0,2) kernel /boot/vmlinuz ro root=/dev/hda3 EOF</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > Otherwise, update /etc/lilo.conf and run lilo: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >cat > /etc/lilo.conf << EOF lba32 boot=/dev/hda prompt timeout=60 image=/boot/vmlinuz label=Linux read-only root=/dev/hda3 EOF lilo</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > You may now restart the system. </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="install-kernel-2.6" ></A >1.4. Installing Linux-2.6.10</H2 ><P > Proceed as described in the previous section, using loop-aes' <EM >kernel-2.6.10.diff</EM > patch instead, and make sure cryptoloop support is <EM >not</EM > activated. Note that modules support require that you have the module-init-tools package installed. </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="install-util-linux" ></A >1.5. Installing util-linux-2.12p</H2 ><P > The losetup program, which is part of the util-linux package, must be patched and recompiled in order to add strong cryptography support. Download, unpack and patch util-linux: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >cd /usr/src wget http://ftp.kernel.org/pub/linux/utils/util-linux/util-linux-2.12p.tar.bz2 tar -xvjf util-linux-2.12p.tar.bz2 cd util-linux-2.12p patch -Np1 -i ../loop-AES-v3.0b/util-linux-2.12p.diff</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > To use passwords that are less than 20 characters, enter: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >CFLAGS="-O2 -DLOOP_PASSWORD_MIN_LENGTH=8"; export CFLAGS</PRE ></FONT ></TD ></TR ></TABLE > </P ><P > Security is certainly your major concern. For this reason, please do not enable passwords shorter than 20 characters. Data privacy is not free, one has to 'pay' in form of long passwords. </P ><P > Compile losetup and install it as root: </P ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" >./configure && make lib mount mv -f /sbin/losetup /sbin/losetup~ rm -f /usr/share/man/man8/losetup.8* cd mount gzip losetup.8 cp losetup /sbin cp losetup.8.gz /usr/share/man/man8/ chattr +i /sbin/losetup</PRE ></FONT ></TD ></TR ></TABLE > </P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="index.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="encrypt-root-filesystem.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Encrypted Root Filesystem HOWTO</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Creating the encrypted root filesystem</TD ></TR ></TABLE ></DIV ></BODY ></HTML >