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Wrapper to mount Private directories without root

DISCUSSION David Obadia 2 participants 3 messages Dec 12, 2012 – Jan 15, 2013 Ecrypt file system

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Not sure why ecryptfs-recover-private requires root, I've found a way to do the same thing without root.

Also I think it would be helpful to have a user friendly API for creating/mounting/unmounting ecrypted folders that doesn't require root using the setuid in mount.ecryptfs_private.

This is what this wrapper script attempts to achieve:
http://paste.ubuntu.com/1427904/

Sample usage is in the header.

Cheers,
David-

#1 lore raw
Quoted 2 lines · David Obadia

Not sure why ecryptfs-recover-private requires root, I've found a way to do the same thing without root.

A quick glance at that script shows that it needs root to do the mount -t ecryptfs ... command. The main eCryptfs mount helper (/sbin/mount.ecryptfs) is big and complex. It hasn't been security audited and setting the setuid bit on it (which would give non-root users sufficient privilege to perform generic eCryptfs mounts) is a bad idea because there are likely security bugs in that program.

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Also I think it would be helpful to have a user friendly API for creating/mounting/unmounting ecrypted folders that doesn't require root using the setuid in mount.ecryptfs_private.

That might be a nice thing to have, but we want mount.ecryptfs_private to stay as simple as possible so that it can be audited and so that we don't introduce new security flaws into the code. It is intentionally locked down to do very specific actions.

Tyler

#2 lore raw
Quoted 2 lines · Tyler Hicks <tyhicks <at> canonical.com> writes:
Quoted 1 line · David Obadia

Not sure why ecryptfs-recover-private requires root, I've found a way to do

the

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same thing without root.

A quick glance at that script shows that it needs root to do the mount -t ecryptfs ... command. The main eCryptfs mount helper (/sbin/mount.ecryptfs) is big and complex.

Understood, that makes sense. That script might pre-date mount.ecryptfs_private? I say this because I was able to achieve the same functionality using only mount.ecryptfs_private, not mount.ecryptfs in my Python script.

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Also I think it would be helpful to have a user friendly API for creating/mounting/unmounting ecrypted folders that doesn't require root

using

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the setuid in mount.ecryptfs_private.

That might be a nice thing to have, but we want mount.ecryptfs_private to stay as simple as possible so that it can be audited and so that we don't introduce new security flaws into the code. It is intentionally locked down to do very specific actions.

Sounds reasonable. Maybe providing a wrapper script gives the best of both world?
1) Minimizes the amount of setuid code that needs to be audited
2) Gives flexibility to the end-user to do as much as can possibly be done, in a user-friendly manner, and without requiring root access.

Would be glad to help,
David-