mirror of
https://github.com/linuxboot/heads.git
synced 2024-12-19 04:57:55 +00:00
130 lines
4.9 KiB
Bash
Executable File
130 lines
4.9 KiB
Bash
Executable File
#!/bin/bash
|
|
# Unseal a LUKS Disk Unlock Key from TPM and add to a new initramfs
|
|
set -e -o pipefail
|
|
. /etc/functions
|
|
|
|
TRACE_FUNC
|
|
|
|
TMP_KEY_DEVICES="/tmp/kexec/kexec_key_devices.txt"
|
|
TMP_KEY_LVM="/tmp/kexec/kexec_key_lvm.txt"
|
|
|
|
INITRD="$1"
|
|
|
|
if [ -z "$INITRD" ]; then
|
|
die "Usage: $0 /boot/initramfs... "
|
|
fi
|
|
|
|
if [ ! -r "$TMP_KEY_DEVICES" ]; then
|
|
die "No devices defined for disk encryption"
|
|
fi
|
|
|
|
if [ -r "$TMP_KEY_LVM" ]; then
|
|
# Activate the LVM volume group
|
|
VOLUME_GROUP=$(cat $TMP_KEY_LVM)
|
|
if [ -z "$TMP_KEY_LVM" ]; then
|
|
die "No LVM volume group defined for activation"
|
|
fi
|
|
lvm vgchange -a y $VOLUME_GROUP ||
|
|
die "$VOLUME_GROUP: unable to activate volume group"
|
|
fi
|
|
|
|
# Measure the LUKS headers before we unseal the LUKS Disk Unlock Key from TPM
|
|
cat "$TMP_KEY_DEVICES" | cut -d\ -f1 | xargs /bin/qubes-measure-luks ||
|
|
die "LUKS measure failed"
|
|
|
|
# Unpack the initrd and fixup the crypttab
|
|
# this is a hack to split it into two parts since
|
|
# we know that the first 0x3400 bytes are the microcode
|
|
INITRD_DIR=/tmp/secret/initrd
|
|
SECRET_CPIO=/tmp/secret/initrd.cpio
|
|
bootdir=$(dirname "$INITRD")
|
|
mkdir -p "$INITRD_DIR/etc"
|
|
|
|
if [ -e /boot/kexec_lukshdr_hash.txt ] && [ -e /tmp/luksDump.txt ]; then
|
|
if ! cmp -s /boot/kexec_lukshdr_hash.txt /tmp/luksDump.txt >/dev/null 2>&1; then
|
|
#LUKS header hash part of detached signed hash digest under boot doesn't match qubes-measure-luks tmp file
|
|
warn "Encrypted disk keys have changed since the TPM Disk Unlock Key was sealed. If you did not make this change, the disk may be compromised"
|
|
exit 1
|
|
else
|
|
#LUKS header hash part of detached signed hash digest matches
|
|
echo "+++ Encrypted disk keys have not been changed since sealed in TPM Disk Unlock Key"
|
|
#TODO: remove "+++" with boot info helper when added, same with "!!!" currently for info.
|
|
fi
|
|
else
|
|
warn "Could not check for tampering of Encrypted disk keys"
|
|
warn "Re-seal the TPM Disk Unlock Key by re-selecting your default boot option to enable this check (Options -> Boot Options -> Show OS boot menu)."
|
|
fi
|
|
|
|
# Attempt to unseal the Disk Unlock Key from the TPM
|
|
# should we give this some number of tries?
|
|
unseal_failed="n"
|
|
if ! kexec-unseal-key "$INITRD_DIR/secret.key"; then
|
|
unseal_failed="y"
|
|
echo
|
|
echo "!!! Failed to unseal the TPM LUKS Disk Unlock Key"
|
|
fi
|
|
|
|
# Override PCR 4 so that user can't read the key
|
|
DEBUG "Extending TPM PCR 4 to prevent further secret unsealing"
|
|
tpmr extend -ix 4 -ic generic ||
|
|
die 'Unable to scramble PCR'
|
|
|
|
# Check to continue
|
|
if [ "$unseal_failed" = "y" ]; then
|
|
confirm_boot="n"
|
|
read \
|
|
-n 1 \
|
|
-p "Do you wish to boot and use the LUKS Disk Recovery Key? [Y/n] " \
|
|
confirm_boot
|
|
echo
|
|
|
|
if [ "$confirm_boot" != 'y' \
|
|
-a "$confirm_boot" != 'Y' \
|
|
-a -n "$confirm_boot" ] \
|
|
; then
|
|
die "!!! Aborting boot due to failure to unseal TPM Disk Unlock Key"
|
|
fi
|
|
fi
|
|
|
|
echo
|
|
echo '+++ Building initrd'
|
|
# pad the initramfs (dracut doesn't pad the last gz blob)
|
|
# without this the kernel init/initramfs.c fails to read
|
|
# the subsequent uncompressed/compressed cpio
|
|
dd if="$INITRD" of="$SECRET_CPIO" bs=512 conv=sync ||
|
|
die "Failed to copy initrd to /tmp"
|
|
|
|
if [ "$unseal_failed" = "n" ]; then
|
|
# kexec-save-default might have created crypttab overrides to be injected in initramfs through additional cpio
|
|
if [ -r "$bootdir/kexec_initrd_crypttab_overrides.txt" ]; then
|
|
echo "+++ $bootdir/kexec_initrd_crypttab_overrides.txt found..."
|
|
echo "+++ Preparing initramfs crypttab overrides as defined under $bootdir/kexec_initrd_crypttab_overrides.txt to be injected through cpio at next kexec call..."
|
|
# kexec-save-default has found crypttab files under initrd and saved them
|
|
cat "$bootdir/kexec_initrd_crypttab_overrides.txt" | while read line; do
|
|
crypttab_file=$(echo "$line" | awk -F ':' {'print $1'})
|
|
crypttab_entry=$(echo "$line" | awk -F ':' {'print $NF'})
|
|
# Replace each initrd crypttab file with modified entry containing /secret.key path
|
|
mkdir -p "$INITRD_DIR/$(dirname $crypttab_file)"
|
|
echo "$crypttab_entry" | tee -a "$INITRD_DIR/$crypttab_file" >/dev/null
|
|
echo "+++ initramfs's $crypttab_file will be overriden with: $crypttab_entry"
|
|
done
|
|
else
|
|
# No crypttab files were found under selected default boot option's initrd file
|
|
# Meanwhile, force crypttab to be created from scratch on both possible locations: /etc/crypttab and /cryptroot/crypttab
|
|
crypttab_files="etc/crypttab cryptroot/crypttab"
|
|
for crypttab_file in $crypttab_files; do
|
|
mkdir -p "$INITRD_DIR/$(dirname $crypttab_file)"
|
|
# overwrite crypttab to mirror behavior of seal-key
|
|
echo "+++ The following $crypttab_file overrides will be passed through concatenated secret/initrd.cpio at kexec call:"
|
|
for uuid in $(cat "$TMP_KEY_DEVICES" | cut -d\ -f2); do
|
|
# NOTE: discard operation (TRIM) is activated by default if no crypptab found in initrd
|
|
echo "luks-$uuid UUID=$uuid /secret.key luks,discard" | tee -a "$INITRD_DIR/$crypttab_file"
|
|
done
|
|
done
|
|
fi
|
|
(
|
|
cd "$INITRD_DIR"
|
|
find . -type f | cpio -H newc -o
|
|
) >>"$SECRET_CPIO"
|
|
fi
|