Steam Deck dual-boot copy Windows Bluetooth Paring

bluetooth-copy.bash

#!/bin/bash

if [[ $# -ne 1 ]]; then
  echo "usage: $0 <windows-partition>"
  echo "  ex.: $0 /dev/nvme0n1p10"
  echo "  ex.: $0 /dev/mmcblk0p3"
  exit 1
fi

if [[ $(id -u) != 0 ]]; then
  echo "run as root"
  sudo -- "$0" "$@"
  exit 1
fi

set -eo pipefail

which chntpw || pacman -Sy chntpw
mkdir -p /mnt/windows
umount /mnt/windows || true
mount /dev/nvme0n1p10 /mnt/windows
trap "cd /; umount /mnt/windows" EXIT

cd /mnt/windows/Windows/System32/config
changed=""

get_value() {
  printf "%s \ControlSet001\Services\BTHPORT\Parameters\Keys\%s\nq\n" "$1" "$2" |
    chntpw -e SYSTEM |
    grep ":0000"
}

ls_devices() {
  printf "ls \ControlSet001\Services\BTHPORT\Parameters\Keys\%s\nq\n" "$1" |
    chntpw -e SYSTEM |
    grep '^\s*<[a-z0-9]*>\s*$'
}

filter_hex() {
  set -- "$@"

  for arg; do
    if [[ ${arg} =~ ^[0-9a-fA-F][0-9a-fA-F]$ ]]; then
      echo "$arg"
    fi
  done
}

get_hex() {
  local value=($(filter_hex $(get_value hex "$1")))

  # join with :
  local IFS="${2}"
  echo "${value[*]}"
}

get_hex_r() {
  local hexstring=""
  for i in $(filter_hex $(get_value hex "$@")); do
    hexstring="$i$hexstring"
  done
  echo "$hexstring"
}

get_dec() {
  local hexstring=$(get_hex_r "$1")
  if [[ -n "$hexstring" ]]; then
    printf "%u" "0x${hexstring}"
  fi
}

# chntpw -e SYSTEM

# 16  3 REG_BINARY         <LTK>
#  4  4 REG_DWORD          <KeyLength>               16 [0x10]
#  8  b REG_QWORD          <ERand>
#  4  4 REG_DWORD          <EDIV>                 56572 [0xdcfc]
# 16  3 REG_BINARY         <IRK>
#  8  b REG_QWORD          <Address>
#  4  4 REG_DWORD          <AddressType>              1 [0x1]
# 16  3 REG_BINARY         <CSRK>
#  4  4 REG_DWORD          <OutboundSignCounter>      0 [0x0]
#  4  4 REG_DWORD          <MasterIRKStatus>          1 [0x1]
#  4  4 REG_DWORD          <AuthReq>                 45 [0x2d]

# git config -f /var/lib/bluetooth/14\:D4\:24\:70\:19\:B0/D4\:61\:2F\:82\:C2\:1B/info --list
# general.name=M720 Triathlon
# general.appearance=0x03c2
# general.addresstype=static
# general.supportedtechnologies=LE
# general.trusted=true
# general.blocked=false
# general.wakeallowed=true
# general.services=00001800-0000-1000-8000-00805f9b34fb
# connectionparameters.mininterval=6
# connectionparameters.maxinterval=9
# connectionparameters.latency=44
# connectionparameters.timeout=216
# identityresolvingkey.key=88A1BA3D0F64994C59A9058545901A6E
# localsignaturekey.key=9D07AAF0395CAA4D91AE97DA1D7A0639
# localsignaturekey.counter=0
# localsignaturekey.authenticated=false
# longtermkey.key=ED235B5197B3673E12BE9F9D2AF019EB
# longtermkey.authenticated=0
# longtermkey.encsize=16
# longtermkey.ediv=42387
# longtermkey.rand=16144039604717484547
# deviceid.source=2
# deviceid.vendor=1133
# deviceid.product=45077
# deviceid.version=9

to_hive_key() {
  local value="$1"
  value="${value//:}"
  value="${value,,}"
  echo "$value"
}

from_hive_key() {
  local value="$1"
  local ret=()

  while [[ -n "$value" ]]; do
    ret+=("${value:0:2}")
    value="${value:2}"
  done

  local IFS=":"
  echo "${ret[*]^^}"
}

update_ini() {
  local hiveType="$1"
  local hivePath="$2"
  local configPath="$3"
  local iniPath="$4"

  local iniValue=$(git config -f "$configPath" --get "$iniPath")
  if [[ -z "$iniValue" ]]; then
    return 0
  fi

  local hiveValue=$(get_$hiveType "$hivePath")
  if [[ -z "$hiveValue" ]]; then
    return 0
  fi
  
  if [[ "$hiveValue" == "$iniValue" ]]; then
    echo ">> The '$iniPath' ($hivePath) is not changed."
    return 0
  fi

  echo ">> Update '$iniValue' ($iniPath) to '$hiveValue' ($hivePath)"
  git config -f "$configPath" --replace-all "$iniPath" "$hiveValue"
  changed="$changed\n$hivePath"
}

find_device_by_irk() {
  local uniqueID="${1}"
  local queryIRK="${2}"

  if [[ -z "$queryIRK" ]]; then
    return 1
  fi

  for configPath in /var/lib/bluetooth/$uniqueID/*/info; do
    local deviceID=$(dirname "$configPath")
    deviceID=$(basename "$deviceID")

    local deviceIRK=$(git config -f "$configPath" --get "IdentityResolvingKey.Key")
    if [[ "$deviceIRK" == "$queryIRK" ]]; then
      echo "$deviceID"
      return 0
    fi
  done

  return 1
}

update_device() {
  local configPath="/var/lib/bluetooth/$1/$2/info"
  local hivePath="$(to_hive_key "$1")\\$(to_hive_key "$2")"

  if [[ ! -e "$configPath" ]]; then
    echo "The '$configPath' does not exist."
    return
  fi

  if [[ ! -e "$configPath.bak" ]]; then
    cp "$configPath" "$configPath.bak"
  fi

  update_ini hex_r "${hivePath}\\IRK" "$configPath" IdentityResolvingKey.Key
  update_ini hex "${hivePath}\\CSRK" "$configPath" LocalSignatureKey.Key
  update_ini hex "${hivePath}\\LTK" "$configPath" LongTermKey.Key
  update_ini dec "${hivePath}\\KeyLength" "$configPath" LongTermKey.EncSize
  update_ini dec "${hivePath}\\EDIV" "$configPath" LongTermKey.EDiv
  update_ini dec "${hivePath}\\ERand" "$configPath" LongTermKey.Rand
  update_ini hex "${hivePath}" "$configPath" LinkKey.Key
}

for uniqueID in /var/lib/bluetooth/*:*; do
  uniqueID=$(basename "$uniqueID")
  hiveUniqueID="$(to_hive_key "$uniqueID")"

  echo "Cloning existing devices with IRK..."
  ls_devices "$hiveUniqueID" | while read hiveDeviceID; do
    hiveDeviceID="${hiveDeviceID//[ <>]}"
    deviceID="$(from_hive_key "$hiveDeviceID")"

    if [[ -e "/var/lib/bluetooth/$uniqueID/$deviceID/info" ]]; then
      continue
    fi

    queryIRK=$(get_hex_r "$hiveUniqueID\\$hiveDeviceID\\IRK")
    if ! otherDeviceID=$(find_device_by_irk "$uniqueID" "$queryIRK"); then
      continue
    fi

    if [[ "$deviceID" == "$otherDeviceID" ]]; then
      continue
    fi

    echo ">> Clonning '$otherDeviceID' to '$deviceID'..."
    cp -rv "/var/lib/bluetooth/$uniqueID/$otherDeviceID" "/var/lib/bluetooth/$uniqueID/$deviceID"
  done

  echo

  for deviceID in /var/lib/bluetooth/$uniqueID/*:*; do
    deviceID=$(basename "$deviceID")
    echo "Updating $deviceID..."
    update_device "$uniqueID" "$deviceID"
    echo
  done
done

if [[ -n "$changed" ]]; then
  echo -e "Changed: $changed"
  systemctl restart bluetooth.service
  systemctl restart graphical.target
fi

echo Done

Do this before running the script:

sudo pacman-key --init
sudo pacman-key --populate archlinux
sudo steamos-readonly disable

This requires that:

1. The device is first paired on SteamOS
2. The device is second paired on Windows
3. The script is run in SteamOS to copy parings from Windows