Home directory permissions mysteriously change upon login/logout! Why?!

[trevorhanning]

My server has multiple users, and I am the administrator. I began to notice problems while connecting via SSH w/ RSA keys. If I was logged into the server already (via a different window), the RSA key would be accepted. If I was not logged in already, the key would be rejected. As it turns out, this has to do with permissions on my /home/me/.ssh directory and my ~/.ssh/authorized_keys file. What boggles my mind is that when I'm logged in, the permissions are set up perfectly. When I log out, my home directory permissions switch (mysteriously, and automatically) to 700. I verified this by logging in as another user and running ls -al /home while logging in/out as myself from another window

When I am logged out, the home directory permissions look like this:

drwxr-xr-x 3 root root 4096 Jun 20 22:29 .ecryptfs
drwx------ 6 trevor trevor 4096 Jun 21 23:11 trevor

However, when I am logged in (whether it be on the machine itself, or via SSH), the permissions on my home directory mysteriously change to:

drwxr-xr-x 3 root root 4096 Jun 20 22:29 .ecryptfs
drwxr-xr-x 6 trevor trevor 4096 Jun 21 23:11 trevor

HOW DOES THIS HAPPEN??!! *totally befuddled*

[steeldriver]

Hello and welcome to the forum

I don't use an encrypted home, so take this with a grain of salt but I think that when you do, your home directory is not actually decrypted and mounted into the filesystem until you login - so probably what you are seeing are the permissions of the empty mount point

If you want to use ssh with encrypted home dirs, then I think you will need to specify an alternative location for your authorized keys file so that it's readable *before* your home directory is decrypted, e.g. in /etc/ssh


/etc/ssh/trevor/authorized_keys

Then modify the sshd_config file



#AuthorizedKeysFile %h/.ssh/authorized_keys
AuthorizedKeysFile /etc/ssh/%u/authorized_keys


Hope this helps

[trevorhanning]

Thanks for the reply steeldriver! I haven't solved it yet, but I think your tip got me headed in the right direction.

[trevorhanning]

https://help.ubuntu.com/community/EncryptedHome

I think steeldriver hit the nail on the head (pun intended ;) If anyone else has this issue, check out the "Caveats" section of the above page.

[trevorhanning]

See this too https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/362427