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heads/initrd/bin/unseal-hotp

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Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
#!/bin/sh
# Retrieve the sealed file and counter from the NVRAM, unseal it and compute the hotp
. /etc/functions
HOTP_SEALED="/tmp/secret/hotp.sealed"
HOTP_SECRET="/tmp/secret/hotp.key"
HOTP_COUNTER="/boot/kexec_hotp_counter"
mount_boot()
{
# Mount local disk if it is not already mounted
if ! grep -q /boot /proc/mounts ; then
mount -o ro /boot \
|| recovery "Unable to mount /boot"
fi
}
tpm nv_readvalue \
-in 4d47 \
-sz 312 \
-of "$HOTP_SEALED" \
|| die "Unable to retrieve sealed file from TPM NV"
tpm unsealfile \
-hk 40000000 \
-if "$HOTP_SEALED" \
-of "$HOTP_SECRET" \
|| die "Unable to unseal HOTP secret"
supress errors on console when files don't exist (equivalent of rm -f)
2019-02-22 01:16:02 +00:00
shred -n 10 -z -u "$HOTP_SEALED" 2> /dev/null
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
Store HOTP counter directly in /boot instead of TPM The HOTP counter isn't a secret but is just used to prevent replay attacks (the time-based counter in TOTP isn't a secret either) so it doesn't need to be protected in the TPM and storing it as a TPM monotonic counter was causing conflicts with the Heads configuration counter as TPM 1.2 can only increment one counter per reboot. This change moves the HOTP counter into the file in /boot that was previously keeping track of the TPM counter id.
2018-06-20 16:20:39 +00:00
# Store counter in file instead of TPM for now, as it conflicts with Heads
# config TPM counter as TPM 1.2 can only increment one counter between reboots
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
# get current value of HOTP counter in TPM, create if absent
mount_boot
Store HOTP counter directly in /boot instead of TPM The HOTP counter isn't a secret but is just used to prevent replay attacks (the time-based counter in TOTP isn't a secret either) so it doesn't need to be protected in the TPM and storing it as a TPM monotonic counter was causing conflicts with the Heads configuration counter as TPM 1.2 can only increment one counter per reboot. This change moves the HOTP counter into the file in /boot that was previously keeping track of the TPM counter id.
2018-06-20 16:20:39 +00:00
#check_tpm_counter $HOTP_COUNTER hotp \
#|| die "Unable to find/create TPM counter"
#counter="$TPM_COUNTER"
#
#counter_value=$(read_tpm_counter $counter | cut -f2 -d ' ' | awk 'gsub("^000e","")')
#
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
Store HOTP counter directly in /boot instead of TPM The HOTP counter isn't a secret but is just used to prevent replay attacks (the time-based counter in TOTP isn't a secret either) so it doesn't need to be protected in the TPM and storing it as a TPM monotonic counter was causing conflicts with the Heads configuration counter as TPM 1.2 can only increment one counter per reboot. This change moves the HOTP counter into the file in /boot that was previously keeping track of the TPM counter id.
2018-06-20 16:20:39 +00:00
counter_value=$(cat $HOTP_COUNTER)
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
if [ "$counter_value" == "" ]; then
Store HOTP counter directly in /boot instead of TPM The HOTP counter isn't a secret but is just used to prevent replay attacks (the time-based counter in TOTP isn't a secret either) so it doesn't need to be protected in the TPM and storing it as a TPM monotonic counter was causing conflicts with the Heads configuration counter as TPM 1.2 can only increment one counter per reboot. This change moves the HOTP counter into the file in /boot that was previously keeping track of the TPM counter id.
2018-06-20 16:20:39 +00:00
die "Unable to read HOTP counter"
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
fi
Store HOTP counter directly in /boot instead of TPM The HOTP counter isn't a secret but is just used to prevent replay attacks (the time-based counter in TOTP isn't a secret either) so it doesn't need to be protected in the TPM and storing it as a TPM monotonic counter was causing conflicts with the Heads configuration counter as TPM 1.2 can only increment one counter per reboot. This change moves the HOTP counter into the file in /boot that was previously keeping track of the TPM counter id.
2018-06-20 16:20:39 +00:00
#counter_value=$(printf "%d" 0x${counter_value})
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
if ! hotp $counter_value < "$HOTP_SECRET"; then
supress errors on console when files don't exist (equivalent of rm -f)
2019-02-22 01:16:02 +00:00
shred -n 10 -z -u "$HOTP_SECRET" 2> /dev/null
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
die 'Unable to compute HOTP hash?'
fi
supress errors on console when files don't exist (equivalent of rm -f)
2019-02-22 01:16:02 +00:00
shred -n 10 -z -u "$HOTP_SECRET" 2> /dev/null
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
Store HOTP counter directly in /boot instead of TPM The HOTP counter isn't a secret but is just used to prevent replay attacks (the time-based counter in TOTP isn't a secret either) so it doesn't need to be protected in the TPM and storing it as a TPM monotonic counter was causing conflicts with the Heads configuration counter as TPM 1.2 can only increment one counter per reboot. This change moves the HOTP counter into the file in /boot that was previously keeping track of the TPM counter id.
2018-06-20 16:20:39 +00:00
#increment_tpm_counter $counter > /dev/null \
#|| die "Unable to increment tpm counter"
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
mount -o remount,rw /boot
Store HOTP counter directly in /boot instead of TPM The HOTP counter isn't a secret but is just used to prevent replay attacks (the time-based counter in TOTP isn't a secret either) so it doesn't need to be protected in the TPM and storing it as a TPM monotonic counter was causing conflicts with the Heads configuration counter as TPM 1.2 can only increment one counter per reboot. This change moves the HOTP counter into the file in /boot that was previously keeping track of the TPM counter id.
2018-06-20 16:20:39 +00:00
counter_value=`expr $counter_value + 1`
echo $counter_value > $HOTP_COUNTER \
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
|| die "Unable to create hotp counter file"
Store HOTP counter directly in /boot instead of TPM The HOTP counter isn't a secret but is just used to prevent replay attacks (the time-based counter in TOTP isn't a secret either) so it doesn't need to be protected in the TPM and storing it as a TPM monotonic counter was causing conflicts with the Heads configuration counter as TPM 1.2 can only increment one counter per reboot. This change moves the HOTP counter into the file in /boot that was previously keeping track of the TPM counter id.
2018-06-20 16:20:39 +00:00
#sha256sum /tmp/counter-$counter > $HOTP_COUNTER \
#|| die "Unable to create hotp counter file"
Add Librem Key support to Heads The Librem Key is a custom device USB-based security token Nitrokey is producing for Purism and among other things it has custom firmware created for use with Heads. In particular, when a board is configured with CONFIG_LIBREMKEY, this custom firmware allows Heads to use the sealed TOTP secret to also send an HOTP authentication to the Librem Key. If the HOTP code is successful, the Librem Key will blink a green LED, if unsuccessful it will blink red, thereby informing the user that Heads has been tampered with without requiring them to use a phone to validate the TOTP secret. Heads will still use and show the TOTP secret, in case the user wants to validate both codes (in case the Librem Key was lost or is no longer trusted). It will also show the result of the HOTP verification (but not the code itself), even though the user should trust only what the Librem Key displays, so the user can confirm that both the device and Heads are in sync. If HOTP is enabled, Heads will maintain a new TPM counter separate from the Heads TPM counter that will increment each time HOTP codes are checked. This change also modifies the routines that update TOTP so that if the Librem Key executables are present it will also update HOTP codes and synchronize them with a Librem Key.
2018-06-19 19:27:27 +00:00
mount -o remount,ro /boot
exit 0
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