I am trying to setup my initramfs with mkinitcpio -P so it decrypts my LUKS/LVM partition containing the root file system on startup.
I followed the steps on here . Everything already works fine, by adding HOOKs encrypt and lvm2 among others, see mkinitcpio.conf below.
Now I would like to have asterisk characters being echoed when I enter the password for the LUKS encrypted partition.
I found a nice command line tool for doing so: systemd-ask-password.
So I modified /etc/mkinitcpio.conf accordingly, so it adds systemd-ask-password as a binary, and /usr/lib/initcpio/hooks/encrypt to use systemd-ask-password for querying the password and pipe the output to cryptsetup and ran mkinitcpio -P.
But it does not mask the password characters with asterisks! It echoes them one by one, which is not secure and not what I intended. In a readily booted system, in a regular terminal and bash, it works perfectly fine. But it seems like the "terminal" during bootup behaves differently. Or the systemd-ask-password command behaves differently in that environment.
How can I get systemd-ask-password to work properly in the boot terminal environment?
Or: Is there a better way to achieve what I want, to echo the password characters as asterisks?
/usr/lib/initcpio/hooks/encrypt:
#!/usr/bin/ash
run_hook() {
modprobe -a -q dm-crypt >/dev/null 2>&1
[ "${quiet}" = "y" ] && CSQUIET=">/dev/null"
# Get keyfile if specified
ckeyfile="/crypto_keyfile.bin"
if [ -n "$cryptkey" ]; then
IFS=: read ckdev ckarg1 ckarg2 <<EOF
$cryptkey
EOF
if [ "$ckdev" = "rootfs" ]; then
ckeyfile=$ckarg1
elif resolved=$(resolve_device "${ckdev}" ${rootdelay}); then
case ${ckarg1} in
*[!0-9]*)
# Use a file on the device
# ckarg1 is not numeric: ckarg1=filesystem, ckarg2=path
mkdir /ckey
mount -r -t "$ckarg1" "$resolved" /ckey
dd if="/ckey/$ckarg2" of="$ckeyfile" >/dev/null 2>&1
umount /ckey
;;
*)
# Read raw data from the block device
# ckarg1 is numeric: ckarg1=offset, ckarg2=length
dd if="$resolved" of="$ckeyfile" bs=1 skip="$ckarg1" count="$ckarg2" >/dev/null 2>&1
;;
esac
fi
[ ! -f ${ckeyfile} ] && echo "Keyfile could not be opened. Reverting to passphrase."
fi
if [ -n "${cryptdevice}" ]; then
DEPRECATED_CRYPT=0
IFS=: read cryptdev cryptname cryptoptions <<EOF
$cryptdevice
EOF
else
DEPRECATED_CRYPT=1
cryptdev="${root}"
cryptname="root"
fi
# This may happen if third party hooks do the crypt setup
if [ -b "/dev/mapper/${cryptname}" ]; then
echo "Device ${cryptname} already exists, not doing any crypt setup."
return 0
fi
warn_deprecated() {
echo "The syntax 'root=${root}' where '${root}' is an encrypted volume is deprecated"
echo "Use 'cryptdevice=${root}:root root=/dev/mapper/root' instead."
}
set -f
OLDIFS="$IFS"; IFS=,
for cryptopt in ${cryptoptions}; do
case ${cryptopt} in
allow-discards)
cryptargs="${cryptargs} --allow-discards"
;;
*)
echo "Encryption option '${cryptopt}' not known, ignoring." >&2
;;
esac
done
set +f
IFS="$OLDIFS"
unset OLDIFS
if resolved=$(resolve_device "${cryptdev}" ${rootdelay}); then
if cryptsetup isLuks ${resolved} >/dev/null 2>&1; then
[ ${DEPRECATED_CRYPT} -eq 1 ] && warn_deprecated
dopassphrase=1
# If keyfile exists, try to use that
if [ -f ${ckeyfile} ]; then
if eval cryptsetup --key-file ${ckeyfile} open --type luks ${resolved} ${cryptname} ${cryptargs} ${CSQUIET}; then
dopassphrase=0
else
echo "Invalid keyfile. Reverting to passphrase."
fi
fi
# Ask for a passphrase
if [ ${dopassphrase} -gt 0 ]; then
echo ""
echo "A password is required to access the ${cryptname} volume:"
#loop until we get a real password
while ! eval systemd-ask-password | cryptsetup open --type luks ${resolved} ${cryptname} ${cryptargs} ${CSQUIET}; do
sleep 2;
done
fi
if [ -e "/dev/mapper/${cryptname}" ]; then
if [ ${DEPRECATED_CRYPT} -eq 1 ]; then
export root="/dev/mapper/root"
fi
else
err "Password succeeded, but ${cryptname} creation failed, aborting..."
return 1
fi
elif [ -n "${crypto}" ]; then
[ ${DEPRECATED_CRYPT} -eq 1 ] && warn_deprecated
msg "Non-LUKS encrypted device found..."
if echo "$crypto" | awk -F: '{ exit(NF == 5) }'; then
err "Verify parameter format: crypto=hash:cipher:keysize:offset:skip"
err "Non-LUKS decryption not attempted..."
return 1
fi
exe="cryptsetup open --type plain $resolved $cryptname $cryptargs"
IFS=: read c_hash c_cipher c_keysize c_offset c_skip <<EOF
$crypto
EOF
[ -n "$c_hash" ] && exe="$exe --hash '$c_hash'"
[ -n "$c_cipher" ] && exe="$exe --cipher '$c_cipher'"
[ -n "$c_keysize" ] && exe="$exe --key-size '$c_keysize'"
[ -n "$c_offset" ] && exe="$exe --offset '$c_offset'"
[ -n "$c_skip" ] && exe="$exe --skip '$c_skip'"
if [ -f "$ckeyfile" ]; then
exe="$exe --key-file $ckeyfile"
else
echo ""
echo "A password is required to access the ${cryptname} volume:"
fi
eval "$exe $CSQUIET"
if [ $? -ne 0 ]; then
err "Non-LUKS device decryption failed. verify format: "
err " crypto=hash:cipher:keysize:offset:skip"
return 1
fi
if [ -e "/dev/mapper/${cryptname}" ]; then
if [ ${DEPRECATED_CRYPT} -eq 1 ]; then
export root="/dev/mapper/root"
fi
else
err "Password succeeded, but ${cryptname} creation failed, aborting..."
return 1
fi
else
err "Failed to open encryption mapping: The device ${cryptdev} is not a LUKS volume and the crypto= paramater was not specified."
fi
fi
rm -f ${ckeyfile}
}
# vim: set ft=sh ts=4 sw=4 et:
/etc/mkinitcpio.conf:
# vim:set ft=sh
# MODULES
# The following modules are loaded before any boot hooks are
# run. Advanced users may wish to specify all system modules
# in this array. For instance:
# MODULES=(piix ide_disk reiserfs)
MODULES=()
# BINARIES
# This setting includes any additional binaries a given user may
# wish into the CPIO image. This is run last, so it may be used to
# override the actual binaries included by a given hook
# BINARIES are dependency parsed, so you may safely ignore libraries
BINARIES=(systemd-ask-password)
# FILES
# This setting is similar to BINARIES above, however, files are added
# as-is and are not parsed in any way. This is useful for config files.
FILES=()
# HOOKS
# This is the most important setting in this file. The HOOKS control the
# modules and scripts added to the image, and what happens at boot time.
# Order is important, and it is recommended that you do not change the
# order in which HOOKS are added. Run 'mkinitcpio -H <hook name>' for
# help on a given hook.
# 'base' is _required_ unless you know precisely what you are doing.
# 'udev' is _required_ in order to automatically load modules
# 'filesystems' is _required_ unless you specify your fs modules in MODULES
# Examples:
## This setup specifies all modules in the MODULES setting above.
## No raid, lvm2, or encrypted root is needed.
# HOOKS=(base)
#
## This setup will autodetect all modules for your system and should
## work as a sane default
# HOOKS=(base udev autodetect block filesystems)
#
## This setup will generate a 'full' image which supports most systems.
## No autodetection is done.
# HOOKS=(base udev block filesystems)
#
## This setup assembles a pata mdadm array with an encrypted root FS.
## Note: See 'mkinitcpio -H mdadm' for more information on raid devices.
# HOOKS=(base udev block mdadm encrypt filesystems)
#
## This setup loads an lvm2 volume group on a usb device.
# HOOKS=(base udev block lvm2 filesystems)
#
## NOTE: If you have /usr on a separate partition, you MUST include the
# usr, fsck and shutdown hooks.
HOOKS=(base udev autodetect keyboard keymap consolefont modconf block encrypt lvm2 filesystems fsck)
# COMPRESSION
# Use this to compress the initramfs image. By default, zstd compression
# is used. Use 'cat' to create an uncompressed image.
#COMPRESSION="zstd"
#COMPRESSION="gzip"
#COMPRESSION="bzip2"
#COMPRESSION="lzma"
#COMPRESSION="xz"
#COMPRESSION="lzop"
#COMPRESSION="lz4"
# COMPRESSION_OPTIONS
# Additional options for the compressor
#COMPRESSION_OPTIONS=()
