ssh jail?

[Todor Petkov]

On 1/25/2016 4:55 PM, Jeffrey Ross wrote:
> I'm in the process of setting up an SSH jail, for the most part its
> working as expected with one exception, I want to provide access to
> /dev/ttyUSB0 through /dev/ttyUSB4 (not 2) via cu.
> 
> When I attempt to use "cu -lttyUSB0 -s9600" I always get "line in use"
> even through it is not in use and from another account not restricted to
> the "jail" I can successfully connect to the ttyUSB0.
> 
> I've tried creating $chroot/
> 
> run/
>     lock/
>     lockdev/
>     uucp/
> var/
>     run -> symbolic link to $chroot/run
>     lock -> symbolic link to $chroot/run/lock
> 
> and then matched the directory permissions so they are the same as the
> "real" system.
> 
> ls -l $chroot/dev/ttyUSB?
>     crwxrwxrwx 1 root dialout 188, 0 Jan 24 14:48 ttyUSB0
>     crwxrwxrwx 1 root dialout 188, 1 Jan 24 14:49 ttyUSB1
>     crwxrwxrwx 1 root dialout 188, 3 Jan 24 14:49 ttyUSB3
>     crwxrwxrwx 1 root dialout 188, 4 Jan 24 14:49 ttyUSB4
> 
> The dialout group is 18 and the user is in group 18, initially I set the
> permissions for the ttyUSB? to 660 before changing it to 777 as a last
> ditch effort.
> 
> The "real" /dev/ttyUSB? -
> 
> ls -l /dev/ttyUSB?
>     crw-rw---- 1 root dialout 188, 0 Jan 24 14:44 /dev/ttyUSB0
>     crw-rw---- 1 root dialout 188, 1 Jan 23 21:48 /dev/ttyUSB1
>     crw-rw---- 1 root dialout 188, 3 Jan 24 15:12 /dev/ttyUSB3
>     crw-rw---- 1 root dialout 188, 4 Jan 23 21:48 /dev/ttyUSB4
> 
> I'm probably missing something simple and any suggestions would be
> appreciated.
> 
> Thanks, Jeff
> 
> 

Hello,

you can try lshell, it gives the user a limited shell with a list of
configurable allowed commands.