From a8228df780af6f803da1a95e22ddea912b9f36ae Mon Sep 17 00:00:00 2001
From: Lukas Greve <please@refre.ch>
Date: Tue, 15 Sep 2026 11:04:19 +0200
Subject: [PATCH] feat: add TPM2 auto-unlock support to encrypted storage
 ingredient

Add cryptsetup, tpm2-tools and tpm2-tss to every encrypted dish so the
initrd can be rebuilt with TPM2 support. A guarded %pre stashes a
preseeded LUKS passphrase from the kickstart, and a guarded %post
enrolls PCR 7-bound auto-unlock via systemd-cryptenroll, switches
crypttab to tpm2-device=auto and regenerates the initrd. Without a
preseeded passphrase or a TPM device the enrollment is skipped and the
system keeps the regular passphrase prompt.
---
 cook/ingredients/storage/encrypted.ks | 67 +++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/cook/ingredients/storage/encrypted.ks b/cook/ingredients/storage/encrypted.ks
index 20a6abc..019671c 100644
--- a/cook/ingredients/storage/encrypted.ks
+++ b/cook/ingredients/storage/encrypted.ks
@@ -6,3 +6,70 @@ clearpart --all --initlabel # Erase all partitions and Initializes the disk labe
 part /boot/efi --fstype="efi" --size=512 --fsoptions="umask=0077,shortname=winnt" --label=efi # Creates a 512 MiB EFI system partition
 part /boot --fstype="ext4" --size=2048 --label=boot # Creates a 2048 MiB ext4 boot partition
 part / --fstype="ext4" --grow --label=root --mkfsoptions="-O encrypt,fast_commit" --encrypted --passphrase= # Create a single encrypted root partition with the remaining space.
+
+# Tools for LUKS management and TPM2-based auto-unlock
+%packages --exclude-weakdeps
+
+cryptsetup # Userspace tool for dm-crypt, required to open and manage the LUKS root device
+tpm2-tools # TPM2 tools, provides the dracut tpm2-tss module needed to rebuild the initrd for TPM2 auto-unlock
+tpm2-tss # TPM2 TSS libraries, runtime dependency of tpm2-tools and systemd-cryptenroll
+
+%end # End of the packages section
+
+# Stash a preseeded LUKS passphrase so the %post below can enroll TPM2-based
+# auto-unlock. Only acts when `--passphrase=` was preseeded on the encrypted
+# `part /` line; with the interactive default (empty passphrase) nothing is
+# stashed and the %post enrollment is skipped cleanly.
+%pre --logfile=/tmp/luks-tpm-pre.log
+
+KS_FILE=""
+for candidate in /run/install/ks.cfg /tmp/ks.cfg; do
+    if [ -f "$candidate" ]; then
+        KS_FILE="$candidate"
+        break
+    fi
+done
+
+if [ -n "$KS_FILE" ]; then
+    LINE=$(grep -E '^[[:space:]]*part[[:space:]]+/[[:space:]].*--encrypted' "$KS_FILE" | grep -- '--passphrase=' | head -n 1)
+    if [ -n "$LINE" ]; then
+        PW=${LINE#*--passphrase=}
+        case "$PW" in
+            \"*) PW=${PW#\"}; PW=${PW%%\"*} ;;
+            *)   PW=${PW%%[[:space:]]*} ;;
+        esac
+        if [ -n "$PW" ]; then
+            printf '%s' "$PW" > /tmp/.luks-passphrase
+            chmod 600 /tmp/.luks-passphrase
+        fi
+    fi
+fi
+
+%end
+
+# Enroll TPM2-based LUKS auto-unlock (PCR 7-bound) when both guards hold: a
+# TPM2 device is available at install time and a passphrase was preseeded in
+# the kickstart (stashed by the %pre above). Otherwise the system keeps the
+# regular passphrase prompt at boot. On any failure the LUKS configuration is
+# left untouched, so the worst case is a passphrase prompt on every boot.
+%post --logfile=/root/luks-tpm-post.log
+
+if [ -e /dev/tpmrm0 ] && [ -s /tmp/.luks-passphrase ]; then
+    set -x
+    LUKSUUID=$(awk '$2 ~ /^UUID=/ {sub(/^UUID=/, "", $2); print $2}' /etc/crypttab)
+    LUKSDEV="/dev/disk/by-uuid/$LUKSUUID"
+    if systemd-cryptenroll --tpm2-device=auto --tpm2-pcrs=7 --unlock-key-file=/tmp/.luks-passphrase "$LUKSDEV"; then
+        sed -i 's| none discard,x-initrd.attach| tpm2-device=auto,discard,x-initrd.attach|' /etc/crypttab
+        if ! grep -q 'tpm2-device=auto' /etc/crypttab; then
+            sed -i -E 's|[[:space:]]none([[:space:]]|$)| tpm2-device=auto,discard\1|' /etc/crypttab
+        fi
+        if grep -q 'tpm2-device=auto' /etc/crypttab; then
+            MID=$(cat /etc/machine-id)
+            KVER=$(ls /usr/lib/modules | head -n 1)
+            dracut -f --kver "$KVER" "/boot/efi/$MID/$KVER/initrd"
+        fi
+    fi
+    shred -u /tmp/.luks-passphrase 2>/dev/null || true
+fi
+
+%end