ssh

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ssh github

Host github.com
	HostName github.com
	User git
	IdentityFile ~/.ssh/github

ssh chroot

Sources

Make home folder

mkdir /home/chroot

Copy library files

#!/bin/bash

cd /home/chroot
mkdir -p {bin,dev,lib,lib64}
mknod dev/null c 1 3
mknod dev/zero c 1 5
chmod 0666 dev/{null,zero}
 
TMPFILE1=./temp1
TMPFILE2=./temp2
 
APPS="
 /usr/bin/whoami
 /bin/uname
 /usr/bin/groups
 /bin/bash
 /bin/cp
 /bin/ls
 /bin/mkdir
 /bin/mv
 /bin/rm
 /bin/rmdir
 /usr/bin/id
 /usr/bin/rsync
 /usr/bin/scp
 /usr/bin/wget
 /usr/bin/vim
 /usr/bin/vi
 /bin/cat
 /bin/less
 /usr/bin/tail
 /usr/bin/clear
 /bin/chmod
 /bin/sh
  /bin/grep
  /bin/gzip
  /bin/gunzip 
  /bin/more
  /bin/pwd
  /bin/ping
  /bin/ps
  /bin/uname
  /bin/sed
  /usr/bin/env
  /usr/bin/host
  /usr/bin/less
  /usr/bin/nslookup
  /usr/bin/dircolors"
 
for app in $APPS;  do
    if [ -x $app ]; then
        app_path=`dirname $app`
        if ! [ -d .$app_path ]; then
            mkdir -p .$app_path
        fi
        cp -p $app .$app
        ldd $app &gt;&gt; ${TMPFILE1}
    fi
done
 
for libs in `cat ${TMPFILE1}`; do
    frst_char="`echo $libs | cut -c1`"
    if [ "$frst_char" = "/" ]; then
        echo "$libs" &gt;&gt; ${TMPFILE2}
    fi
done
 
for lib in `cat ${TMPFILE2}`; do
        mkdir -p .`dirname $lib` &gt; /dev/null 2&gt;&amp;1
        cp $lib .$lib
done
 
cp -r /lib/terminfo ./lib/
 
rm -f $TMPFILE1
rm -f $TMPFILE2

Move the user's files to the jail

mv /home/myuser /home/chroot/home/

Link the user's home to stay compatible with the old one

ln -s /home/chroot/home/myuser /home/myuser

Change the perms on this folder

chmod 700 /home/chroot/home/myuser

Set the config in /etc/ssh/sshd_config

Load the internal sftp server

#Subsystem sftp /usr/lib/openssh/sftp-server
Subsystem sftp internal-sftp

The difference between both is that the internal sftp server does not need to copy binary files to the jail.

Define a rule for the user (or group)

# we are matching the user but this can be a group also
Match User myuser
  ChrootDirectory /home/chroot
  AllowTCPForwarding no
  X11Forwarding no
Match

Then we need to define an environment.

to prevent having an invite like : I have no name!@machine, we need to define some environment variables.

ssh tunnels

Local / Remote

A = 4321
B = 127.0.0.1
C = 3306
D = me@myserver.com

ssh -N -L 4321:127.0.0.1:3306 me@myserver.com

The command is calling on port A the machine B that is connected to machine D that connects to machine B on port C.

-N = quiet mode (no ssh console)
-L = local mode (inverse is -R as remote)

Then we can use :

mysql -h 127.0.0.1 -P 4444 -u user -p mybase

Dynamic

ssh -N -D 4321 me@myserver.com

Then we can configure the proxy clients to use SOCKS with 127.0.0.1 as host and 4321 as port.

sshfs

Source

# aptitude install fuse fuse-utils sshfs

sshfs login@server:/home/login/ /mnt/tmp/

umount :

fusermount -u /mnt/tmp/

Example scripts

#!/bin/bash

# check if params
if [ $# -lt 2 ];then
  echo "Usage : sshmnt <ssh alias> <folder name>"
  exit;
fi

if [ ! -d ~/mnt/$2 ]; then
  echo "no ~/mnt/$2 folder found. creating it"
  mkdir -p ~/mnt/$2
  if [ $? -eq 0 ]; then
    exit 1;
  fi
fi

sshfs $1 ~/mnt/$2

#!/bin/bash

# check if params
if [ $# -lt 1 ];then
  echo "Usage : sshmnt <folder name>"
  exit;
fi

if [ ! -d ~/mnt/$1 ]; then
  echo "no ~/mnt/$2 folder found."
fi

fusermount -u ~/mnt/$1

ssh