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Scripts_MiSTer/firewall_on.sh
2021-08-23 12:14:36 -06:00

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6.2 KiB
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#!/bin/bash
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# Copyright 2019 Alessandro "Locutus73" Miele
# You can download the latest version of this script from:
# https://github.com/MiSTer-devel/Scripts_MiSTer
# Version 1.0.4 - 2021-08-23 - New method for checking if the script is run on a real MiSTer system (thanks to MiSTer Addons).
# Version 1.0.3 - 2019-02-05 - Cosmetic changes.
# Version 1.0.2 - 2019-02-03 - Remounting / as RW only when needed; downgraded version from 1.1 to 1.0.2.
# Version 1.0.1 - 2019-02-02 - Remounting / as RW before altering /etc/init.d/ so the script actually works from OSD.
# Version 1.0 - 2019-02-02 - First commit
if [ ! -f "/media/fat/MiSTer" ];
then
echo "This script must be run"
echo "on a MiSTer system."
exit 1
fi
if ! iptables -L > /dev/null 2>&1
then
echo "The current Kernel doesn't support iptables/firewalling."
echo "Please fix that before running this script,"
echo "i.e. updating your MiSTer Linux and/or running security_fixes.sh."
exit 1
fi
if [ ! -f /media/fat/linux/iptables.up.rules ]
then
IPTABLES_UP_RULES="*filter"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# Allows all loopback (lo0) traffic and drop all traffic to 127/8 that doesn't use lo0"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -i lo -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT ! -i lo -d 127.0.0.0/8 -j REJECT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# Accepts all established inbound connections"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# Allows all outbound traffic"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# You could modify this to only allow certain traffic"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A OUTPUT -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# Allows SSH connections"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# The --dport number is the same as in /etc/ssh/sshd_config"
if [ -f /etc/init.d/S50sshd ]
then
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -p tcp -m state --state NEW --dport 22 -j ACCEPT"
else
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"#-A INPUT -p tcp -m state --state NEW --dport 22 -j ACCEPT"
fi
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# Now you should read up on iptables rules and consider whether ssh access"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# for everyone is really desired. Most likely you will only allow access from certain IPs."
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# Allows FTP connections"
if [ -f /etc/init.d/S50proftpd ]
then
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -p tcp -m state --state NEW --dport 21 -j ACCEPT"
else
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"#-A INPUT -p tcp -m state --state NEW --dport 21 -j ACCEPT"
fi
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# Allows Samba connections"
if [ -f /etc/init.d/S91smb ]
then
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -p udp -m state --state NEW --dport 137 -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -p udp -m state --state NEW --dport 138 -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -p tcp -m state --state NEW --dport 139 -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -p tcp -m state --state NEW --dport 445 -j ACCEPT"
else
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"#-A INPUT -p udp -m state --state NEW --dport 137 -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"#-A INPUT -p udp -m state --state NEW --dport 138 -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"#-A INPUT -p tcp -m state --state NEW --dport 139 -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"#-A INPUT -p tcp -m state --state NEW --dport 445 -j ACCEPT"
fi
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# Allow ping"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# note that blocking other types of icmp packets is considered a bad idea by some"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# remove -m icmp --icmp-type 8 from this line to allow all kinds of icmp:"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# https://security.stackexchange.com/questions/22711"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# log iptables denied calls (access via 'dmesg' command)"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -m limit --limit 5/min -j LOG --log-prefix \"iptables denied: \" --log-level 7"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"# Reject all other inbound - default deny unless explicitly allowed policy:"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A INPUT -j REJECT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"-A FORWARD -j REJECT"
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'""
IPTABLES_UP_RULES=$IPTABLES_UP_RULES$'\n'"COMMIT"
echo "$IPTABLES_UP_RULES" > /media/fat/linux/iptables.up.rules
fi
mount | grep "on / .*[(,]ro[,$]" -q && RO_ROOT="true"
[ "$RO_ROOT" == "true" ] && mount / -o remount,rw
echo "#!/bin/bash"$'\n'"iptables-restore < /media/fat/linux/iptables.up.rules" > /etc/network/if-pre-up.d/iptables
chmod +x /etc/network/if-pre-up.d/iptables
sync
[ "$RO_ROOT" == "true" ] && mount / -o remount,ro
/etc/network/if-pre-up.d/iptables
echo "Firewall is on and"
echo "active at startup."
echo "Done!"
exit 0