Shell in a box
Shell in a Box allows you to control a computer over the network using a Linux console in a web page.
Contents
Install it
Get it
- open a console as root.
- Download shell in a box from google
<source>
wget http://shellinabox.googlecode.com/files/shellinabox-2.14.tar.gz
</source>
- unpack it
<source>
tar xvzf shellinabox-2.14.tar.gz
</source>
-
find out your distribution and install some dependencies,
-
for SUSE Linux:
<source>
yast -i make gcc
</source>
for Ubuntu:
<source>
apt-get update
apt-get install make gcc
</source>
- build it
<source>
cd shellinabox-2.14 ./configure && make && make install
</source>
- make sure the firewall is open, here is an example for SUSE Linux:
<source>
rcSuSEfirewall2 stop
</source>
- you are not allowed to log in as root, so make sure you have at least one ordinary user. Add a user name user like this:
<source>
useradd -m user passwd user
</source>
- call shell in a box
<source>
cd /tmp shellinaboxd &
</source>
- test it by surfing to your computer: http://localhost:4200
Make it persistent
You want the shell in a box daemon shellinaboxd to be started when booting your machine, so
for SUSE Linux
- add the following line to /etc/init.d/boot.local:
<source>
shellinaboxd &
</source>
- configure the firewall to always open up port 80 or stop it persistantly:
<source>
chkconfig SuSEfirewall2_setup off chkconfig SuSEfirewall2_init off
</source>
- configure apache to start on boot
<source>
chkconfig apache2 on
</source>
for Ubuntu
To start the shellinabox daemon after reboot add the following line to /etc/crontab: <source>
@reboot root /usr/local/bin/shellinaboxd &
</source> This will start the daemon only on reboot as a background job.
Use in a web server
You probably want shell in a box to be reachable via port 80 (so you can use it from within a typical corporate network) and you may want to run a web server on the same machine. So here is how you integrate shell in a box into an Apache2 web server
for SUSE Linux
- install apache2, in this example for SUSE Linux 12.1:
<source>
yast -i apache2
</source>
- enable a reverse proxy. To do this, edit /etc/sysconfig/apache2 and add the following words to APACHE_MODULES: proxy proxy_http. In the end your line may read like this:
<source>
APACHE_MODULES="actions alias auth_basic proxy proxy_http authn_file authz_host authz_groupfile authz_default authz_user autoindex cgi dir env expires include log_config mime negotiation setenvif ssl userdir php5"
</source>
- tell apache that if someone calls http://yourserver.yourdomain/shell this is forwarded to http://yourserver.yourdomain:4200 internally. To do this, edit /etc/apache2/default-server.conf, add a block
<source>
<IfModule mod_proxy.c>
<Location /shell>
ProxyPass http://127.0.0.1:4200
</Location>
</IfModule>
</source>
- now set up apache for https so your passwords are not transmitted unencrypted over the internet
for Ubuntu
- install apache2
<source>
apt-get install apache2
</source>
- enable apache's proxy module:
<source>
a2enmod proxy
</source>
- do
<source>
ln -s /etc/apache2/mods-available/proxy_http.load /etc/apache2/mods-enabled/proxy_http.load
</source>
- tell apache that if someone calls http://yourserver.yourdomain/shell this is forwarded to http://yourserver.yourdomain:4200 internally. To do this, edit /etc/apache2/sites-enabled/000-default, add a block:
<source>
<Location /shell>
ProxyPass http://127.0.0.1:4200
Allow from 127.0.0.1
</Location>
</source>
- restart apache
<source>
/etc/init.d/apache2 restart
</source>
- test if the module has indeed been loaded:
<source>
# apache2ctl -t -D DUMP_MODULES 2>&1 | grep proxy_http proxy_http_module (shared)
</source>
- now set up apache for https so your passwords are not transmitted unencrypted over the internet
TroubleShooting
cannot read valid certificate
Symptom: ShellInABoxD does not start, it tells the error message: <source>
Cannot read valid certificate from "certificate.pem". Check file permissions and file format.
</source>
Reason: See http://code.google.com/p/shellinabox/issues/detail?id=59. ShellInABoxD tries to create a file certificate.pem in the folder where it is started as user nobody: <source>
/tmp # ll certificate.pem -rw------- 1 nobody nogroup 2794 Aug 5 07:53 certificate.pem
</source>
Solution: Start shellinaboxd in a directory that every user can access, e.g. /tmp: <source>
cd /tmp shellinaboxd &
</source>
forkpty() failed
- Symptom
- When you surf to the shellinabox page you see an error message
<source>
forkpty() failed
</source>
- Solution
- Kill all shellinaboxd processes and start them with root privileges:
<source>
killall shellinaboxd shellinaboxd --user=0 & disown
</source>
minus sign
- Symptom
- The minus sign does not work if you type it on the keypad.
- Solution
- I could fix this by using Safari instead of FireFox
