Local SOCKS Proxy for Safari (See related posts)

Surfing the web with Safari (3.0.4) on Mac OS X 10.4 can be made a bit more private & secure by setting up a local SOCKS Proxy on an admin user account.
Use the following BASH command-line instructions at your own risk!

I. Setting up a local SOCKS proxy for Safari on a single admin user account

# first enable remote login on your admin user account: System Preferences > Sharing > Services > Remote Login

# test if remote login is enabled
sudo launchctl list | grep com.openssh.sshd                               # com.openssh.sshd
defaults read /System/Library/LaunchDaemons/ssh
netstat -an | awk '/\*\.22[[:space:]]+.*LISTEN$/ {print}'                 # tcp4 ... *.22 ... LISTEN
service --test-if-available ssh; echo $?                                  # 0
service --test-if-configured-on ssh; echo $?                              # 0

# test if sshd daemon supports tcp_wrappers
# cf. http://www.la-samhna.de/library/brutessh.html#5
otool -L /usr/sbin/sshd | grep libwrap                                      

# then make sure you are connected to the internet
ping -c 10 checkip.dyndns.org
curl -L -s --max-time 10 http://checkip.dyndns.org | grep -Eo -m 1 '([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}'   


# then set up the local SOCKS Proxy
# cf. http://macapper.com/2007/05/22/advanced-os-x-secure-tunneling-via-ssh

#ssh -q -D 8080 -f -C -N -x $(whoami)@$(ipconfig getifaddr $(route -n get default | awk '/interface:/ { print $2 }') 2>/dev/null)
#ssh -v -D 8080 -f -C -N -x $(whoami)@$(ipconfig getifaddr $(route -n get default | awk '/interface:/ { print $2 }') 2>/dev/null) 

ssh -q -D 8080 -f -C -N -x $(whoami)@127.0.0.1     # cf. AllowUsers $(whoami)@127.0.0.1 below

# ... enter your user account login password


# SSH Without a Password
# http://www.csua.berkeley.edu/~ranga/notes/ssh_nopass.html
# http://homepage.mac.com/kelleherk/iblog/C1901548470/E20061128145420/index.html

# RSA
mkdir -p $HOME/.ssh
chmod -R 0700 $HOME/.ssh
ssh-keygen -t rsa -f $HOME/.ssh/id_rsa -P ''
cp -p $HOME/.ssh/id_rsa.pub $HOME/.ssh/authorized_keys2
chmod 0600 $HOME/.ssh/authorized_keys2
srm -v $HOME/.ssh/id_rsa.pub
#ls -ld $HOME/.ssh
#ls -l $HOME/.ssh/authorized_keys2

# encrypt the known_hosts file
ssh-keygen -H -f $HOME/.ssh/known_hosts 
srm -v $HOME/.ssh/known_hosts.old
chmod 0600 $HOME/.ssh/known_hosts


# securing SSH
# See:
# - man sshd_config
# - sudo nano /private/etc/sshd_config
# - http://switch.richard5.net/2006/09/24/securing-your-ssh-access/ 
# - http://www.mactech.com/articles/mactech/Vol.21/21.02/Security/index.html
# - Mac OS X Security Configuration Guides at http://www.apple.com/server/documentation/

sudo sh -c "
echo '
# added
Protocol 2
PermitRootLogin no
PermitEmptyPasswords no
ChallengeResponseAuthentication no
PasswordAuthentication no
UsePAM no
PubkeyAuthentication yes
AuthorizedKeysFile $HOME/.ssh/authorized_keys2
#KeepAlive yes
MaxAuthTries 3
LoginGraceTime 40
LogLevel INFO     # QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG
#AllowUsers $(whoami)      # add more users if you like: ~  (in Terminal.app) or dscl . -list /Users
AllowUsers $(whoami)@127.0.0.1      # cf. ssh -q -D 8080 -f -C -N -x $(whoami)@127.0.0.1 above
#AllowUsers $(whoami)@$(ipconfig getifaddr $(route -n get default | awk '/interface:/ { print $2 }') 2>/dev/null)   # requires internet connection
#AllowGroups sshusersgroup     # cf. dscl . -list /Groups; groups
' >> /private/etc/sshd_config
"


# then open Safari ...

open -a Safari

# ... and go to:
# Safari > Preferences ... > Advanced > Proxies: Change Settings ... 
# > Select a proxy server to configure: SOCKS Proxy > SOCKS Proxy Server: 127.0.0.1 : 8080 > Apply Now


sudo reboot       # ... or just restart: System Preferences > Sharing > Services > Remote Login

ssh -q -D 8080 -f -C -N -x $(whoami)@127.0.0.1      # should now work without password; cf. man ssh_config for configuring SSH shortcuts


# check local SOCKS Proxy setup

scutil --proxy                   # SOCKSProxy : 127.0.0.1, SOCKSEnable : 1, SOCKSPort : 8080

sudo ln -s "/Applications/Utilities/Network Utility.app/Contents/Resources/stroke" /bin/portscan
portscan localhost 8000 8100     # Open TCP Port:  8080  http-alt

lsof -i :22 -P
lsof -i :8080 -P
lsof -i TCP -P
lsof -U -P             # list UNIX domain socket files
sudo lsof -U -P
netstat -n -f inet


#-------------------------- 


# now you can, for example, test if a website can discover your real internal IP address provided your computer
# is behind a DSL router and you have a firewall running (cf. http://textsnippets.com/posts/show/1267)
# cf. http://www.auditmypc.com/internal-ip.html

# first get your internal IP address
ipconfig getifaddr $(route -n get default | awk '/interface:/ { print $2 }')

# note: to run the 'real IP' test you first have to enable Plug-ins, Java & JavaScript in Safari
# Safari > Preferences ... > Security > Enable plug-ins & Enable Java & Enable JavaScript

open -a Safari http://www.auditmypc.com/software_audit.asp

II. Setting up a local SOCKS proxy for Safari using two different user accounts on the same computer

# The following BASH command-line instructions assume you have a regular user account 
# and an admin user account on the same computer!

# First, log in to the regular user account 
regular_user_name="$(whoami)"
regular_user_path="$HOME"
echo $regular_user_name $regular_user_path    

# note down the output from the echo command
# log out from the regular user account

# Then log in to the admin account for the following instructions!

# first make sure you are connected to the internet
ping -c 10 checkip.dyndns.org
curl -L -s --max-time 10 http://checkip.dyndns.org | grep -Eo -m 1 '([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}'   

# get internal IP address & set regular user account information
regular_user_name="...insert information from regular user account above..."
regular_user_path="...insert information from regular user account above..."
internal_IP_address=$(ipconfig getifaddr $(route -n get default | awk '/interface:/ { print $2 }'))
echo $internal_IP_address $regular_user_name $regular_user_path

# enable remote login: System Preferences > Sharing > Services > Remote Login

# test if remote login is enabled
service --test-if-available ssh; echo $?               # 0
service --test-if-configured-on ssh; echo $?           # 0


# SSH Without a Password

# admin user account
# RSA
mkdir -p $HOME/.ssh
chmod -R 0700 $HOME/.ssh
ssh-keygen -t rsa -f $HOME/.ssh/id_rsa -P ''
cp -p $HOME/.ssh/id_rsa.pub $HOME/.ssh/authorized_keys2
chmod 0600 $HOME/.ssh/authorized_keys2
srm -v $HOME/.ssh/id_rsa.pub
ls -ld $HOME/.ssh
ls -l $HOME/.ssh

# regular user account
sudo mkdir -p $regular_user_path/.ssh
sudo chmod -R 0700 $regular_user_path/.ssh
sudo cp $HOME/.ssh/authorized_keys2 $regular_user_path/.ssh/authorized_keys2
#scp ~/.ssh/authorized_keys2 $regular_user_name@$internal_IP_address:~/.ssh/authorized_keys2
sudo chown -R $regular_user_name:$regular_user_name $regular_user_path/.ssh
sudo chmod 0600 $regular_user_path/.ssh/authorized_keys2
sudo ls -l $regular_user_path/.ssh
sudo ls -ld $regular_user_path/.ssh

# delete all files in ~/.ssh on both user accounts
#sudo find $regular_user_path/.ssh -type f -exec srm -fv "{}" \;
#find $HOME/.ssh -type f -exec srm -fv "{}" \;


# log in to regular user account via SSH
# enter admin account login password if prompted
ssh -i $HOME/.ssh/id_rsa $regular_user_name@$internal_IP_address     
exit

# encrypt the known_hosts file
ssh-keygen -H -f $HOME/.ssh/known_hosts       
srm -v $HOME/.ssh/known_hosts.old
chmod 0600 $HOME/.ssh/known_hosts

ssh -i $HOME/.ssh/id_rsa $regular_user_name@$internal_IP_address    # test
ls 
exit


# securing SSH
# man sshd_config
# sudo nano /private/etc/sshd_config

sudo sh -c "
echo '
# added
Protocol 2
PermitRootLogin no
PermitEmptyPasswords no
ChallengeResponseAuthentication no
PasswordAuthentication no
UsePAM no
PubkeyAuthentication yes
#AuthorizedKeysFile $regular_user_path/.ssh/authorized_keys2
#KeepAlive yes
MaxAuthTries 3
#PermitUserEnvironment yes     # requires ~/.ssh/environment file; see man ssh and man sshd_config
LoginGraceTime 40
LogLevel INFO     # QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG
#AllowUsers $(whoami) $regular_user_name
AllowUsers $(whoami)@$internal_IP_address $regular_user_name@$internal_IP_address
' >> /private/etc/sshd_config
"


# set up the local SOCKS Proxy
# enter admin account login password if prompted
ssh -q -D 8080 -f -C -N -x $regular_user_name@$internal_IP_address    

open -a Safari

# Safari > Preferences ... > Advanced > Proxies: Change Settings ... 
# > Select a proxy server to configure: SOCKS Proxy > SOCKS Proxy Server: 127.0.0.1 : 8080 > Apply Now

# restart sshd: System Preferences > Sharing > Services > Remote Login

# check local SOCKS Proxy setup
scutil --proxy                    # SOCKSProxy : 127.0.0.1, SOCKSEnable : 1, SOCKSPort : 8080
portscan localhost 8000 8100      # Open TCP Port:  8080  http-alt

ssh -p 22 $regular_user_name@$internal_IP_address ls
ssh -l $regular_user_name $internal_IP_address 'echo hello world; whoami; hostname; logname'

# test privacy of internal IP address
open -a Safari http://www.auditmypc.com/software_audit.asp

Further information on SSH & Mac OS X:

- Getting started with SSH
- Remote Login With SSH
- SSH Without A Password
- Exit Your SSH Session Without Killing Your Job
- SSH on Mac OS X
- SSH
- ssh tunnelling
- ssh X forwarding debugging
- Tutorial: SSH To Alternate Ports and Enabling Multiple SSH Daemons
- Route All Your Internet Traffic Through a Proxy
- SSH Notes
- SSH Host Key Protection
- Setup the SSH server to use keys for authentication
- Auto-closing SSH tunnels
- SSH Tunnelling (Port Forwarding)
- Defending against brute force ssh attacks
- SSH + Screen = Easy Administration
- SSH SOCKS Proxy From Behind a Gateway
- nylon - flexible Unix proxy server with mirror mode; sudo port install nylon
- tsocks - transparent SOCKS proxying library; sudo port install tsocks