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62 lines
1.9 KiB
Bash
Executable File
62 lines
1.9 KiB
Bash
Executable File
#!/bin/sh
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# Unseal a disk key from TPM and add to a new initramfs
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set -e -o pipefail
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. /etc/functions
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TMP_KEY_DEVICES="/tmp/kexec/kexec_key_devices.txt"
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TMP_KEY_LVM="/tmp/kexec/kexec_key_lvm.txt"
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INITRD="$1"
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if [ -z "$INITRD" ]; then
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die "Usage: $0 /boot/initramfs... "
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fi
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if [ ! -r "$TMP_KEY_DEVICES" ]; then
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die "No devices defined for disk encryption"
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fi
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if [ -r "$TMP_KEY_LVM" ]; then
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# Activate the LVM volume group
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VOLUME_GROUP=`cat $TMP_KEY_LVM`
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if [ -z "$TMP_KEY_LVM" ]; then
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die "No LVM volume group defined for activation"
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fi
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lvm vgchange -a y $VOLUME_GROUP \
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|| die "$VOLUME_GROUP: unable to activate volume group"
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fi
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# Measure the LUKS headers before we unseal the disk key
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cat "$TMP_KEY_DEVICES" | cut -d\ -f1 | xargs /bin/qubes-measure-luks \
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|| die "LUKS measure failed"
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# Unpack the initrd and fixup the /etc/crypttab
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# this is a hack to split it into two parts since
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# we know that the first 0x3400 bytes are the microcode
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INITRD_DIR=/tmp/secret/initrd
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SECRET_CPIO=/tmp/secret/initrd.cpio
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mkdir -p "$INITRD_DIR/etc"
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# Attempt to unseal the disk key from the TPM
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# should we give this some number of tries?
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if ! kexec-unseal-key "$INITRD_DIR/secret.key" ; then
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die 'Unseal disk key failed'
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fi
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# Override PCR 4 so that user can't read the key
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tpm extend -ix 4 -ic generic \
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|| die 'Unable to scramble PCR'
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echo '+++ Building initrd'
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# pad the initramfs (dracut doesn't pad the last gz blob)
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# without this the kernel init/initramfs.c fails to read
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# the subsequent uncompressed/compressed cpio
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dd if="$INITRD" of="$SECRET_CPIO" bs=512 conv=sync \
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|| die "Failed to copy initrd to /tmp"
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# overwrite /etc/crypttab to mirror the behavior for in seal-key
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for uuid in `cat "$TMP_KEY_DEVICES" | cut -d\ -f2`; do
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echo "luks-$uuid UUID=$uuid /secret.key" >> "$INITRD_DIR/etc/crypttab"
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done
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( cd "$INITRD_DIR" ; find . -type f | cpio -H newc -o ) >> "$SECRET_CPIO"
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