#!/bin/bash

###
#
#            Name:  reissue_filevault_recovery_key.sh
#     Description:  This script is intended to run on Macs which no longer have
#                   a valid recovery key in the JSS. It prompts users to enter
#                   their Mac password, and uses this password to generate a
#                   new FileVault key and escrow with the JSS. The "redirect
#                   FileVault keys to JSS" configuration profile must already
#                   be deployed in order for this script to work correctly.
#          Author:  Elliot Jordan <elliot@elliotjordan.com>
#         Created:  2015-01-05
#   Last Modified:  2017-11-16
#         Version:  1.9
#
###


################################## VARIABLES ##################################

# Company logo. (Tested with PNG, JPG, GIF, PDF, and AI formats.)
LOGO="/private/var/jamf/images/logo.png"

# The title of the message that will be displayed to the user.
# Not too long, or it'll get clipped.
PROMPT_TITLE="Encryption Key Escrow"

# The body of the message that will be displayed before prompting the user for
# their password. All message strings below can be multiple lines.
PROMPT_MESSAGE="Your Mac's FileVault encryption key needs to be escrowed by PretendCo IT.

Click the Next button below, then enter your Mac's password when prompted."

# The body of the message that will be displayed after 5 incorrect passwords.
FORGOT_PW_MESSAGE="You made five incorrect password attempts.

Please contact the Help Desk at 555-1212 for help with your Mac password."

# The body of the message that will be displayed after successful completion.
SUCCESS_MESSAGE="Thank you! Your FileVault key has been escrowed."

# The body of the message that will be displayed if a failure occurs.
FAIL_MESSAGE="Sorry, an error occurred while escrowing your FileVault key. Please contact the Help Desk at 555-1212 for help."

# Optional but recommended: The profile identifiers of the FileVault Key
# Redirection profiles (e.g. ABCDEF12-3456-7890-ABCD-EF1234567890).
PROFILE_IDENTIFIER_10_12="" # 10.12 and earlier
PROFILE_IDENTIFIER_10_13="" # 10.13 and later


###############################################################################
######################### DO NOT EDIT BELOW THIS LINE #########################
###############################################################################


######################## VALIDATION AND ERROR CHECKING ########################

# Suppress errors for the duration of this script. (This prevents JAMF Pro from
# marking a policy as "failed" if the words "fail" or "error" inadvertently
# appear in the script output.)
exec 2>/dev/null

BAILOUT=false

# Make sure we have root privileges (for fdesetup).
if [[ $EUID -ne 0 ]]; then
    REASON="This script must run as root."
    BAILOUT=true
fi

# Check for remote users.
REMOTE_USERS=$(/usr/bin/who | grep -Eo '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | wc -l)
if [[ $REMOTE_USERS -gt 0 ]]; then
    REASON="Remote users are logged in."
    BAILOUT=true
fi

# Make sure the custom logo file is present.
if [[ ! -f "$LOGO" ]]; then
    REASON="Custom logo not present: $LOGO"
    BAILOUT=true
fi

# Convert POSIX path of logo icon to Mac path for AppleScript
LOGO_POSIX="$(/usr/bin/osascript -e 'tell application "System Events" to return POSIX file "'"$LOGO"'" as text')"

# Bail out if jamfHelper doesn't exist.
jamfHelper="/Library/Application Support/JAMF/bin/jamfHelper.app/Contents/MacOS/jamfHelper"
if [[ ! -x "$jamfHelper" ]]; then
    REASON="jamfHelper not found."
    BAILOUT=true
fi

# Most of the code below is based on the JAMF reissueKey.sh script:
# https://github.com/JAMFSupport/FileVault2_Scripts/blob/master/reissueKey.sh

# Check the OS version.
OS_MAJOR=$(/usr/bin/sw_vers -productVersion | awk -F . '{print $1}')
OS_MINOR=$(/usr/bin/sw_vers -productVersion | awk -F . '{print $2}')
if [[ "$OS_MAJOR" -ne 10 || "$OS_MINOR" -lt 9 ]]; then
    REASON="This script requires macOS 10.9 or higher. This Mac has $(sw_vers -productVersion)."
    BAILOUT=true
elif [[ "$OS_MAJOR" -eq 10 && "$OS_MINOR" -ge 13 ]]; then
    echo "[WARNING] This script is still in BETA in High Sierra, because the fdesetup binary has changed significantly. Please use with caution."
fi

# Check to see if the encryption process is complete
FV_STATUS="$(/usr/bin/fdesetup status)"
if grep -q "Encryption in progress" <<< "$FV_STATUS"; then
    REASON="FileVault encryption is in progress. Please run the script again when it finishes."
    BAILOUT=true
elif grep -q "FileVault is Off" <<< "$FV_STATUS"; then
    REASON="Encryption is not active."
    BAILOUT=true
elif ! grep -q "FileVault is On" <<< "$FV_STATUS"; then
    REASON="Unable to determine encryption status."
    BAILOUT=true
fi

# Get the logged in user's name
CURRENT_USER=$(/usr/bin/python -c 'from SystemConfiguration import SCDynamicStoreCopyConsoleUser; import sys; username = (SCDynamicStoreCopyConsoleUser(None, None, None) or [None])[0]; username = [username,""][username in [u"loginwindow", None, u""]]; sys.stdout.write(username + "\n");')

# Make sure there's an actual user logged in
if [[ -z $CURRENT_USER || "$CURRENT_USER" == "root" ]]; then
    REASON="No user is currently logged in."
    BAILOUT=true
else
    # Make sure logged in account is already authorized with FileVault 2
    FV_USERS="$(/usr/bin/fdesetup list)"
    if ! egrep -q "^${CURRENT_USER}," <<< "$FV_USERS"; then
        REASON="$CURRENT_USER is not on the list of FileVault enabled users: $FV_USERS"
        BAILOUT=true
    fi
fi

# If specified, the FileVault key redirection profile needs to be installed.
if [[ "$OS_MAJOR" -eq 10 && "$OS_MINOR" -le 12 ]]; then
    if [[ "$PROFILE_IDENTIFIER_10_12" != "" ]]; then
        if ! /usr/bin/profiles -Cv | grep -q "profileIdentifier: $PROFILE_IDENTIFIER_10_12"; then
            REASON="The FileVault Key Redirection profile is not yet installed."
            BAILOUT=true
        fi
    fi
elif [[ "$OS_MAJOR" -eq 10 && "$OS_MINOR" -gt 12 ]]; then
    if [[ "$PROFILE_IDENTIFIER_10_13" != "" ]]; then
        if ! /usr/bin/profiles -Cv | grep -q "profileIdentifier: $PROFILE_IDENTIFIER_10_13"; then
            REASON="The FileVault Key Redirection profile is not yet installed."
            BAILOUT=true
        fi
    fi
fi


################################ MAIN PROCESS #################################

# Get information necessary to display messages in the current user's context.
USER_ID=$(/usr/bin/id -u "$CURRENT_USER")
if [[ "$OS_MAJOR" -eq 10 && "$OS_MINOR" -le 9 ]]; then
    L_ID=$(/usr/bin/pgrep -x -u "$USER_ID" loginwindow)
    L_METHOD="bsexec"
elif [[ "$OS_MAJOR" -eq 10 && "$OS_MINOR" -gt 9 ]]; then
    L_ID=$USER_ID
    L_METHOD="asuser"
fi

# If any error occurred in the validation section, bail out.
if [[ "$BAILOUT" == "true" ]]; then
    echo "[ERROR]: $REASON"
    launchctl "$L_METHOD" "$L_ID" "$jamfHelper" -windowType "utility" -icon "$LOGO" -title "$PROMPT_TITLE" -description "$FAIL_MESSAGE: $REASON." -button1 'OK' -defaultButton 1 -startlaunchd &>/dev/null &
    exit 1
fi

# Display a branded prompt explaining the password prompt.
echo "Alerting user $CURRENT_USER about incoming password prompt..."
/bin/launchctl "$L_METHOD" "$L_ID" "$jamfHelper" -windowType "utility" -icon "$LOGO" -title "$PROMPT_TITLE" -description "$PROMPT_MESSAGE" -button1 "Next" -defaultButton 1 -startlaunchd &>/dev/null

# Get the logged in user's password via a prompt.
echo "Prompting $CURRENT_USER for their Mac password..."
USER_PASS="$(/bin/launchctl "$L_METHOD" "$L_ID" /usr/bin/osascript -e 'display dialog "Please enter the password you use to log in to your Mac:" default answer "" with title "'"${PROMPT_TITLE//\"/\\\"}"'" giving up after 86400 with text buttons {"OK"} default button 1 with hidden answer with icon file "'"${LOGO_POSIX//\"/\\\"}"'"' -e 'return text returned of result')"

# Thanks to James Barclay (@futureimperfect) for this password validation loop.
TRY=1
until /usr/bin/dscl /Search -authonly "$CURRENT_USER" "$USER_PASS" &>/dev/null; do
    (( TRY++ ))
    echo "Prompting $CURRENT_USER for their Mac password (attempt $TRY)..."
    USER_PASS="$(/bin/launchctl "$L_METHOD" "$L_ID" /usr/bin/osascript -e 'display dialog "Sorry, that password was incorrect. Please try again:" default answer "" with title "'"${PROMPT_TITLE//\"/\\\"}"'" giving up after 86400 with text buttons {"OK"} default button 1 with hidden answer with icon file "'"${LOGO_POSIX//\"/\\\"}"'"' -e 'return text returned of result')"
    if (( TRY >= 5 )); then
        echo "[ERROR] Password prompt unsuccessful after 5 attempts. Displaying \"forgot password\" message..."
        /bin/launchctl "$L_METHOD" "$L_ID" "$jamfHelper" -windowType "utility" -icon "$LOGO" -title "$PROMPT_TITLE" -description "$FORGOT_PW_MESSAGE" -button1 'OK' -defaultButton 1 -startlaunchd &>/dev/null &
        exit 1
    fi
done
echo "Successfully prompted for Mac password."

# If needed, unload and kill FDERecoveryAgent.
if /bin/launchctl list | grep -q "com.apple.security.FDERecoveryAgent"; then
    echo "Unloading FDERecoveryAgent LaunchDaemon..."
    /bin/launchctl unload /System/Library/LaunchDaemons/com.apple.security.FDERecoveryAgent.plist
fi
if pgrep -q "FDERecoveryAgent"; then
    echo "Stopping FDERecoveryAgent process..."
    killall "FDERecoveryAgent"
fi

# Translate XML reserved characters to XML friendly representations.
USER_PASS=${USER_PASS//&/&amp;}
USER_PASS=${USER_PASS//</&lt;}
USER_PASS=${USER_PASS//>/&gt;}
USER_PASS=${USER_PASS//\"/&quot;}
USER_PASS=${USER_PASS//\'/&apos;}

# For 10.13's escrow process, store the last modification time of /var/db/FileVaultPRK.dat
if [[ "$OS_MINOR" -ge 13 ]]; then
    echo "Checking for /var/db/FileVaultPRK.dat on macOS 10.13+..."
    PRK_MOD=0
    if [ -e "/var/db/FileVaultPRK.dat" ]; then
        echo "Found existing personal recovery key."
        PRK_MOD=$(/usr/bin/stat -f "%Sm" -t "%s" "/var/db/FileVaultPRK.dat")
    fi
fi

echo "Issuing new recovery key..."
FDESETUP_OUTPUT="$(/usr/bin/fdesetup changerecovery -norecoverykey -verbose -personal -inputplist << EOF
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Username</key>
    <string>$CURRENT_USER</string>
    <key>Password</key>
    <string>$USER_PASS</string>
</dict>
</plist>
EOF
)"

# Clear password variable.
unset USER_PASS

# Test success conditions.
FDESETUP_RESULT=$?
# Differentiate <=10.12 and >=10.13 success conditions
if [[ "$OS_MINOR" -ge 13 ]]; then
    # Check new modification time of of FileVaultPRK.dat
    ESCROW_STATUS=1
    if [ -e "/var/db/FileVaultPRK.dat" ]; then
        NEW_PRK_MOD=$(/usr/bin/stat -f "%Sm" -t "%s" "/var/db/FileVaultPRK.dat")
        if [[ $NEW_PRK_MOD -gt $PRK_MOD ]]; then
            ESCROW_STATUS=0
            echo "Recovery key updated locally and available for collection via MDM."
        else
            echo "[WARNING] The recovery key does not appear to have been updated locally."
        fi
    fi
else
    # Check output of fdesetup command for indication of an escrow attempt
    grep -q "Escrowing recovery key..." <<< "$FDESETUP_OUTPUT"
    ESCROW_STATUS=$?
fi

if [[ $FDESETUP_RESULT -ne 0 ]]; then
    [[ -n "$FDESETUP_OUTPUT" ]] && echo "$FDESETUP_OUTPUT"
    echo "[WARNING] fdesetup exited with return code: $FDESETUP_RESULT."
    echo "See this page for a list of fdesetup exit codes and their meaning:"
    echo "https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man8/fdesetup.8.html"
    echo "Displaying \"failure\" message..."
    /bin/launchctl "$L_METHOD" "$L_ID" "$jamfHelper" -windowType "utility" -icon "$LOGO" -title "$PROMPT_TITLE" -description "$FAIL_MESSAGE: fdesetup exited with code $FDESETUP_RESULT. Output: $FDESETUP_OUTPUT" -button1 'OK' -defaultButton 1 -startlaunchd &>/dev/null &
elif [[ $ESCROW_STATUS -ne 0 ]]; then
    [[ -n "$FDESETUP_OUTPUT" ]] && echo "$FDESETUP_OUTPUT"
    echo "[WARNING] FileVault key was generated, but escrow cannot be confirmed. Please verify that the redirection profile is installed and the Mac is connected to the internet."
    echo "Displaying \"failure\" message..."
    /bin/launchctl "$L_METHOD" "$L_ID" "$jamfHelper" -windowType "utility" -icon "$LOGO" -title "$PROMPT_TITLE" -description "$FAIL_MESSAGE: New key generated, but escrow did not occur." -button1 'OK' -defaultButton 1 -startlaunchd &>/dev/null &
else
    [[ -n "$FDESETUP_OUTPUT" ]] && echo "$FDESETUP_OUTPUT"
    echo "Displaying \"success\" message..."
    /bin/launchctl "$L_METHOD" "$L_ID" "$jamfHelper" -windowType "utility" -icon "$LOGO" -title "$PROMPT_TITLE" -description "$SUCCESS_MESSAGE" -button1 'OK' -defaultButton 1 -startlaunchd &>/dev/null &
fi

exit $FDESETUP_RESULT