Re: [Jailkit-users] Some problems with home directories and users with same user id

[Olivier Sessink]

Daniel Rossi wrote:
> Hi there, I am currently implementing jailkit support into the ISPConfig 
> software. I've run into issues trying to get a chrooted user to login to 
> their own home directory. With the new version of the server, a 'parent' 
> web user ie web1 is created with a group called client0 etc. When adding 
> shell users to this account / site , the shell user gets the same user 
> id and group id as the parent web user for permissions etc. The parent 
> web user does not get a shell login, it gets sent to /bin/false.

I think you're walkin on thin ice. Although it works in several 
situations, AFAIK the results of having multiple users with the same 
user ID are undefined. I'm not completely sure though, perhaps this is 
compliant with the posix standards.

> The issue I am having is logback sees the logged in user as the parent 
> user web1 so is trying to login to it's home directory not the logged in 
> users directory.

what happens is that the jk_chroot runs with user ID 0, and once inside 
the jail has to become the normal user again. So once inside the jail 
jk_chrootsh looks up the username of the original user ID, and becomes 
that user. If you have multiple usernames associated with that user ID 
the results are pretty much undefined.

regards,
        Olivier