#!/bin/bash
# **** License ****
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# 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.
#
# This code was originally developed by Vyatta, Inc.
# Portions created by Vyatta are Copyright (C) 2007 Vyatta, Inc.
# All Rights Reserved.
#
# Author:	Bob Gilligan <gilligan@vyatta.com>
# Description:	Standalone script to set the admin passwd to new value
#		value.  Note:  This script can ONLY be run as a standalone
#		init program by grub.
#
# **** End License ****

# The Vyatta config file:
CF=/opt/vyatta/etc/config/config.boot

# Admin user name
ADMIN=vyos

set_encrypted_password() {
    local user_raw=$1 epwd=$2 file=$3
    local user

    # Escape the username before using it in awk/sed regexes
    user=$(printf '%s' "$user_raw" | sed -e 's/\./\\&/g')

    # Check if encrypted-password exists within this specific user's block
    if awk "/ user $user \{/{f=1} f && /encrypted-password/{found=1; exit} f && /^        }/{exit} END{exit !found}" "$file"; then
        # Replace existing encrypted-password line
        sed -i \
           -e "/ user $user {/,/encrypted-password/s/encrypted-password .*\$/encrypted-password \"$epwd\"/" "$file"
    else
        # Key-only account: no encrypted-password or plaintext-password line exists
        # in this user's block (e.g. authentication via SSH key only).
        if awk "/ user $user \{/{f=1} f && /authentication \{/{found=1; exit} f && /^        \}/{exit} END{exit !found}" "$file"; then
            # 'authentication' block exists - insert encrypted-password inside it
            sed -i \
               -e "/ user $user {/,/authentication {/s/\(authentication {\)\$/\1\n                encrypted-password \"$epwd\"/" "$file"
        else
            # No authentication block at all. Without this branch the sed range
            # above would overrun the block boundary and corrupt a later account's
            # authentication block. Build the section from scratch instead.
            sed -i \
               -e "/ user $user {/a\\
            authentication {\\
                encrypted-password \"$epwd\"\\
                plaintext-password \"\"\\
            }" "$file"
        fi
    fi
}

clear_plaintext_password() {
    local user_raw=$1 file=$2
    local user

    # Escape the username before using it in awk/sed regexes
    user=$(printf '%s' "$user_raw" | sed -e 's/\./\\&/g')

    # Only clear if plaintext-password exists within this specific user's block.
    # Without this guard, if the user has no plaintext-password line the sed
    # range never closes inside their block and spills into the next account
    # that does have one, wiping that account's plaintext-password instead.
    if awk "/ user $user \{/{f=1} f && /plaintext-password/{found=1; exit} f && /^        \}/{exit} END{exit !found}" "$file"; then
        sed -i \
           -e "/ user $user {/,/plaintext-password/s/plaintext-password .*\$/plaintext-password \"\"/" "$file"
    fi
}


# How long to wait for user to respond, in seconds
TIME_TO_WAIT=30

change_password() {
    local user=$1
    local pwd1="1"
    local pwd2="2"

    until [ "$pwd1" == "$pwd2" ]
    do
        read -p "Enter $user password: " -r -s pwd1
	echo
	read -p "Retype $user password: " -r -s pwd2
	echo

	if [ "$pwd1" != "$pwd2" ]
	then echo "Passwords do not match"
	fi
    done

    # set the password for the user then store it in the config
    # so the user is recreated on the next full system boot.
    local epwd=$(mkpasswd --method=yescrypt "$pwd1")
    # escape any slashes in resulting password
    local eepwd=$(sed 's:/:\\/:g' <<< $epwd)
    set_encrypted_password $user $eepwd $CF

    # There is issue that 'set_encrypted_password' only handles the 'encrypted-password' line,
    # but leaves any existing 'plaintext-password' untouched (T8346).
    # We need to clear 'plaintext-password' for the user during the password change flow.
    clear_plaintext_password $user $CF
}

# System is so messed up that doing anything would be a mistake
dead() {
    echo $*
    echo
    echo "This tool can only recover missing administrator password."
    echo "It is not a full system restore"
    echo
    echo -n "Hit return to reboot system: "
    read
    /sbin/reboot -f
}

echo "Standalone root password recovery tool."
echo
#
# Check to see if we are running in standalone mode.  We'll
# know that we are if our pid is 1.
#
if [ "$$" != "1" ]; then
    echo "This tool can only be run in standalone mode."
    exit 1
fi

#
# OK, now we know we are running in standalone mode.  Talk to the
# user.
#
echo -n "Do you wish to reset the admin password? (y or n) "
read -t $TIME_TO_WAIT response
if [ "$?" != "0" ]; then
    echo
    echo "Response not received in time."
    echo "The admin password will not be reset."
    echo "Rebooting in 5 seconds..."
    sleep 5
    echo
    /sbin/reboot -f
fi

response=${response:0:1}
if [ "$response" != "y" -a "$response" != "Y" ]; then
    echo "OK, the admin password will not be reset."
    echo -n "Rebooting in 5 seconds..."
    sleep 5
    echo
    /sbin/reboot -f
fi

echo -en "Which admin account do you want to reset? [$ADMIN] "
read admin_user
ADMIN=${admin_user:-$ADMIN}

echo "Starting process to reset the admin password..."

echo "Re-mounting root filesystem read/write..."
mount -o remount,rw /

if [ ! -f /etc/passwd ]
then dead "Missing password file"
fi

if [ ! -d /opt/vyatta/etc/config ]
then dead "Missing VyOS config directory /opt/vyatta/etc/config"
fi

# Leftover from V3.0
if grep -q /opt/vyatta/etc/config /etc/fstab
then
    echo "Mounting the config filesystem..."
    mount /opt/vyatta/etc/config/
fi

if [ ! -f $CF ]
then dead "$CF file not found"
fi

if ! grep -q 'system {' $CF
then dead "$CF file does not contain system settings"
fi

if ! grep -q ' login {' $CF
then
    # Recreate login section of system
    sed -i -e '/system {/a\
    login {\
    }' $CF
fi

if ! grep -q " user $ADMIN " $CF
then
    echo "Recreating administrator $ADMIN in $CF..."
    sed -i -e "/ login {/a\\
        user $ADMIN {\\
            authentication {\\
                encrypted-password \$6$IhbXHdwgYkLnt/$VRIsIN5c2f2v4L2l4F9WPDrRDEtWXzH75yBswmWGERAdX7oBxmq6m.sWON6pO6mi6mrVgYBxdVrFcCP5bI.nt.\\
                plaintext-password \"\"\\
            }\\
            level admin\\
        }" $CF
fi

echo "Saving backup copy of config.boot..."
cp $CF ${CF}.before_pwrecovery
sync

echo "Setting the administrator ($ADMIN) password..."
change_password $ADMIN

echo $(date "+%b%e %T") $(hostname) "Admin password changed" \
    | tee -a /var/log/auth.log  >>/var/log/messages

sync

echo "System will reboot in 10 seconds..."
sleep 10
/sbin/reboot -f