Added a script to restore host secrets to shm

script/host/tpm/secrets.sh

@@ -0,0 +1,145 @@
+#!/bin/bash
+
+
+
+function checkPreconditions() {
+    ! checkTPM \
+        && echo >&2 \
+        && echo "TPM 2.0 device missing." >&2 \
+        && return 1
+
+    ! checkTools \
+        && echo >&2 \
+        && echo 'TPM tools missing. Setup via: "apt install tpm2-tools"' >&2 \
+        && return 1
+
+    return 0
+}
+
+function checkSafe() {
+    printf -- "%s" 'Checking TPM derived safe ... ' >&2 \
+        && [ -f /root/tpm/aes-key-safe.priv ] \
+        && [ -f /root/tpm/aes-key-safe.pub ] \
+        && printf -- "%s\n" '(found)' >&2 \
+        && return 0
+
+    printf -- "%s\n" '(missing)' >&2
+    return 1
+}
+
+function checkTools() {
+    printf -- "%s" 'Checking TPM tools ... ' >&2 \
+        && tpm2_createprimary --version > /dev/null 2>&1 \
+        && tpm2_create --version > /dev/null 2>&1 \
+        && tpm2_load --version > /dev/null 2>&1 \
+        && tpm2_unseal --version > /dev/null 2>&1 \
+        && printf -- "%s\n" '(installed)' >&2 \
+        && return 0
+
+    return 1
+}
+
+function checkTPM() {
+    printf -- "%s" 'Checking TPM device ... ' >&2 \
+        && [ -f /sys/class/tpm/tpm0/tpm_version_major ] \
+        && [ $(cat /sys/class/tpm/tpm0/tpm_version_major) -ge 2 ] 2> /dev/null \
+        && printf -- "%s\n" '(available)' >&2 \
+        && return 0
+
+    return 1
+}
+
+function checkOrCreateSafe() {
+    checkSafe \
+        && return 0
+
+    [ -f /root/tpm/aes-key-safe.priv ] \
+        && echo 'ABORT existing safe file found: "/root/tpm/aes-key-safe.priv"' >&2 \
+        && return 1
+
+    [ -f /root/tpm/aes-key-safe.pub ] \
+        && echo 'ABORT existing safe file found: "/root/tpm/aes-key-safe.pub"' >&2 \
+        && return 1
+
+    printf -- "%s" 'Creating TPM derived safe ... ' >&2
+    umask 077
+    mkdir -p /root/tpm
+    [ -f /tmp/primary.ctx ] || tpm2_createprimary -C o -Q -c /tmp/primary.ctx
+    openssl rand 32 | tpm2_create -C /tmp/primary.ctx -Q -i - -r /root/tpm/aes-key-safe.priv -u /root/tpm/aes-key-safe.pub \
+        && [ -f /root/tpm/aes-key-safe.priv ] \
+        && [ -f /root/tpm/aes-key-safe.pub ] \
+        && printf -- "%s\n" '(done)' >&2 \
+        && return 0
+
+    echo 'FAILURE: unable to provide a usable safe.' >&2
+    return 1
+}
+
+function seal() {
+    ! chmod -R go-rwx /dev/shm/host/secret/* \
+        && return 1
+
+    [ -f /tmp/primary.ctx ] || tpm2_createprimary -C o -Q -c /tmp/primary.ctx
+    [ -f /tmp/safe.ctx ] || tpm2_load \
+        -C /tmp/primary.ctx -Q \
+        -r /root/tpm/aes-key-safe.priv \
+        -u /root/tpm/aes-key-safe.pub \
+        -c /tmp/safe.ctx
+    umask 077
+    openssl enc -aes-256-cbc -salt -pbkdf2 \
+        -in <(tar -czvf - /dev/shm/host/secret/*) \
+        -out /root/tpm/host_secrets.tar.gz.aes \
+        -pass file:<(tpm2_unseal -c /tmp/safe.ctx)
+}
+
+function unseal() {
+    ! [ -f /root/tpm/host_secrets.tar.gz.aes ] \
+        && return 1
+
+    [ -f /tmp/primary.ctx ] || tpm2_createprimary -C o -Q -c /tmp/primary.ctx
+    [ -f /tmp/safe.ctx ] || tpm2_load \
+        -C /tmp/primary.ctx -Q \
+        -r /root/tpm/aes-key-safe.priv \
+        -u /root/tpm/aes-key-safe.pub \
+        -c /tmp/safe.ctx
+    openssl enc -d -aes-256-cbc -pbkdf2 \
+        -in /root/tpm/host_secrets.tar.gz.aes \
+        -out - \
+        -pass file:<(tpm2_unseal -c /tmp/safe.ctx) | tar -xzvf - -C /
+}
+
+function usage() {
+    echo
+    echo 'Commands:'
+    echo '  --seal          : This will save the secrets of this host in a secure way.'
+    echo '                       A safe is created automatically and will not be overwritten,'
+    echo '                       you have to delete both safe files to replace an existing safe,'
+    echo '                       BUT you will loose access to the AES key inside, so BE CAREFUL!'
+    echo '  --unseal        : This restores the secrets after a reboot.'
+
+    return 0
+}
+
+
+
+checkPreconditions || exit 1
+
+case "${1}" in
+    --seal)
+        checkOrCreateSafe \
+            && seal \
+            && exit 0
+        ;;
+    --unseal)
+        checkSafe \
+            && unseal \
+            && exit 0
+        ;;
+    *)
+        echo "Unknown command '${1}'"
+        usage
+        exit 1
+        ;;
+esac
+
+exit 1