[scponly] Further // usage confusion ... possible bug ?

[Ensel Sharon]

A few months ago I asked for some clarification about the // usage in
/etc/passwd that divides the chroot point from the writeable user incoming
directory (or whatever you want to call it).

I am seeing behavior that confuses me and would like to know why that
behavior manifests itself, or if it is a bug.



On Tue, 20 Dec 2005, wby oblyr wrote:

> And yes, I'm painfully aware of how inadquate the documentation is around this feature.  Basically, the gist is 
> this:
> 
> Users of the scponlyc shell must not be able to modify their home directories, lest they be able to subvert the 
> restricted shell by modifying things like ssh configuration.  Many people complained that after logging into a 
> scponly shell, they could not upload files, so the '//' thing was devised.
> 
> imagine this home directory:
> 
> /home/scponlyuser//incoming
> 
> everything BEFORE the // is the chroot path (/home/scponlyuser) and everything after the // is a directory to 
> chdir() into after chrooting.  This way a user can log into their scponly shell and the following will happen:
> 
> - scponlyc will chroot to /home/scponlyuser
> - scponlyc will then chdir to /incoming (inside the chroot), dropping the user into a directory they can upload 


Ok, I get it.  I really do.  But if that is the case, then a /etc/passwd
home-directory line like this:

/usr/home//username

(where the chroot supporting etc/usr/bin directories for multiple users
are in /usr/home)

Should allow me to scp like this:

scp /file username at servername:/

but it doesn't - I _still_ have to specify the subdirectory on the scp
command line:

scp /file username at servername:/username

So ... what gives ?  If the purpose of the data after the // is to
"dropping the user into a directory they can upload" then why isn't it
dropping me in there ?  I might as well just leave the home directory in
/etc/passwd as:

/usr/home

if I have to specify the sub-dir on the client remote command anyway...

Comments ?