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TrueCrypt 4.3 on Fedora 7 : Build from Zero

Sun, Jul 1, 2007 mdda OSS Blog Comments

TrueCrypt 4.3 on Fedora 7 : Build from Zero

NB: Ripped (and modified) from : http://tredosoft.com/comment/reply/37

How to install TrueCrypt 4.3a on Fedora 7

We are going to compile TrueCrypt from source so first grab TrueCrypt’s source code. When it’s downloaded, extract the source code and navigate to the Linux folder :

tar xfz truecrypt-4.3a-source-code.tar.gz  
cd truecrypt-4.3a-source-code  
cd Linux  

Truecrypt needs to compile a kernel module during the build process. Unfortunately the kernel headers included with Fedora 7 (in the kernel-devel package) are missing the dm.h header file which is needed for compiling the kernel module.

We need to download the source RPM for the kernel (it’s roughly a 45MB download) and install it so we can get to the dm.h file. Since this is for the release version of Fedora 7 (which has the 2.6 kernel) the commands to get at the source would be…

su  
yumdownloader --source kernel  
; mkdir /usr/src/redhat # May have to do this due to packaging problems  
rpm -ivh kernel-$(uname -r).src.rpm  
; yum install sparse # May need this if rpmbuild complains  
``rpmbuild -bp --target=noarch /usr/src/redhat/SPECS/kernel-2.6.spec  
; there's a lot of activity at this point...`

`; Now copy over the dm.h file into the right place... (make sure the kernel major-minor matches the current) :  
cp /usr/src/redhat/BUILD/kernel-2.6.22/linux-2.6.22.noarch/drivers/md/dm.h /usr/src/kernels/$(uname -r)-$(uname -m)/drivers/md/  

Once we are done installing the source RPM we edit the build.sh file located in TrueCrypt’s Linux folder. To do this, change the line :

KERNEL_SRC=/lib/modules/$KERNEL_VER/source`  


to

  

KERNEL_SRC=/usr/src/redhat/BUILD/$KERNEL_VER/vanilla

save and run `build.sh` as root to start the build process  


  
`su  
./build.sh  

still logged in as root run the install script and modprobe the kernel module, using an ‘su -’ login to set the root paths properly :

./install.sh  
/sbin/modprobe truecrypt  

We successfully installed truecrypt!

To load this as a normal user, we need to create a mount point, and then use the truecrypt command with the –user-mount option :

mkdir /media/Fieldstone  
truecrypt --user-mount /media/1GB/Fieldstone.truecrypt /media/Fieldstone  

Previously, to make this work, one needed to chown u+s /usr/bin/truecrypt (which was convenient, if a little insecure according to the truecrypt website). Now, with version 4.3a, this method of allowing a regular user to ‘escalate’ privileges to mount the volume doesn’t work. So the user has to be made ‘sudo’ capable. As root, do ‘/usr/sbin/visudo’ (ugg - I hate vi, try export EDITOR=joe first to avoid using this). Navigate to the bottom of the file, (and, if in vi hit ‘i’ for insert mode) and add :

_username_        ALL=/usr/bin/truecrypt  

where username is the user that will be using truecrypt. That should do the trick, and then the two commands :

truecrypt --user-mount /media/1GB/Fieldstone.truecrypt /media/Fieldstone  
truecrypt --dismount  

should work. Phew!


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