Problems using encryption software
 

Hi
I have used truecrypt as portable backup between OS including w$

Ubuntu works well. however, Fedora16 mounts my vfat harddisk partition readwrite but my pendrive vfat partition readonly, evan as root. I have tried many mount options from posts, specifying the filesystem, uid's, gid's, shmee-id's, you name it, I've had a go.

So I moved to realcrypt. That always prompts for a root password, then the truecrypt partitions mount as root only, with no ability to change- but now (at last) with read-write access.

I have setup sudoers and can start anything as user with su privileges, and the files can then be viewed by user, but now mounted read only. However, I feel that a line to allow access to whatever command launches realcrypt might work.

What I would like to achieve is any form of container encryption that I can move between platforms. I use scripts to backup, and the present rootonly access will cause problems.

I feel I'm getting close to a solution.

Is there something I can do to modify the way realcrypt starts up? At present I can see that usr/bin/realcrypt is only a link to /usr/bin/consolehelper but changing my sudoers to allow user to run commands realcrypt and consolehelper as root, in the same way as /usr/bin/truecrypt (btw the latter is only a filename, not a command) has had no effect. So I haven't been able to achieve the startup as user, which might solve the problem.

I hope someone has seen the same problem- but if not please point me in a direction to solve it.

If not, then I'll go outside the box and use encrypted tarballs to achieve the same, but I fear it'll be messy.

That's odd. If the pen drive is mounted ro at the HW level then no VFS option will turn ro into rw. Do you mount the pen drive at boot or do you insert it only when needed? Does it make a difference when you insert it? What's the pen drives layout? Do all partitions fsck OK? What's the subsystem that automounts devices? Is it the same in both distributions? And what's the /etc/fstab difference in both distributions? Any clues in 'dmesg'?

Thank you for the reply
Working through your queries:

I insert the pen drive when needed, but there is no difference if it is inserted when I boot up.

Layout:
Result of fsck- I have noted from other posts that this type of issue occurs with damaged filesystems and that fsck repairs have been effective, but firstly believe that this has been used only on partitions that mount directly- fsck should only be forced on a truecrypt partition in read only mode, also my truecrypt partition is working on another OS. Here is the result:

partition 1 (fat32)
partition 2 (truecrypt, unmounted)
partition 2 (truecrypt mounted)
Subsystem that mounts devices:
I don't know how to access this info. I have seen references to "memstick" as the subsystem for ubuntu but have not found anything corresponding for fedora

You mention fstab, but I only mount using truecrypt favourites, therefore fstab has no entries relating to this issue- so I have shown the relevant part of mtab:

fedora, partition mounted with truecrypt:
and the relevant entry when mounted with realcrypt:
mtab, ubuntu, mounted using truecrypt:
I can see differences, but don't know how to intervene.

As you suspected, dmesg provided some clues, but I can't derive a solution from them:

fedora, device inserted:
fedora, truecrypt mount:

fedora, truecrypt dismount:
fedora, realcrypt mount: (first line may be irrelevant)
ubuntu, device inserted:
Ubuntu, nothing on dmesg when truecrypt mounted

Thanks for the output, much appreciated. So as it seems Ubuntu mounts Truecrypt volume 2 OK and Fedora mounts the Realcrypt volume OK but at a the device-mapper level Fedora detects Truecrypt volume 2 contains VFAT errors... Now as far as I've read Realcrypt is basically modified Truecrypt so if Realcrypt reads Truecrypt volume 2 OK then maybe go with that? I don't know where to start troubleshooting Fedora device-mapper problems the quick and easy way.

Agreed, I'm not going to try anything else. Something in /usr/sbin/realcrypt will not allow any user except root to run Realcrypt, even with an appropriate sudoers entry. It would be necessary to examine the code, and neither eclipse nor HT has been able to interpret the file.

Truecrypt now mounts read-write!

I have made significant changes since the above posts, by downloading kde. This requires the installation of a large number of applications, and I can only assume that one or more of these have changed the way Fedora handles removable media (recalling that there has never been a problem with mounting hd partitions, including encrypted ones). Perhaps something related to the trayicon for handling media?

I will not mark as solved as I don't know why the problem has gone away.

For now, I don't propose to do anything else, but if it will assist other users I will try to answer questions relating to this installation.