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meta-cyber-secureboot/recipes-core/initrdscripts/files/ecryptfs

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#!/bin/sh
#!/bin/sh
#@author: vincent.benoit <vincent.benoit@scle.fr>
#@date: 10/2023
#@brief: ecryptfs and TPM
check_tpm2() {
if [ ! -e /sys/class/tpm ]; then
echo "Linux TPM subsystem not found"
exit 1
fi
}
ecryptfs_enabled() {
return 0
}
create_tpm_prim_key() {
local dirpath=$1
if [ -z ${dirpath} ]; then
echo "err: dir path (${dirpath}) doesn't exist"
exit 1
fi
check_tpm2
local contextfile=${dirpath}/key.ctxt
local ret=`/usr/bin/tpm2_createprimary --key-algorithm=rsa2048 --key-context=${contextfile} 2>/dev/null`
if [ $? -ne 0 ]; then
echo "err: create primary failed"
exit 1
fi
}
persistent_handle() {
local handle=$1
storage_prim_key=""
local tmp_res=/tmp/persist.txt
local ret=`/usr/bin/tpm2_evictcontrol -c ${handle} > ${tmp_res}`
if [ $? -eq 0 ]; then
local res=`cat ${tmp_res} | tail -1 | awk -F ": " '{print $2}'`
if [ $res == "persisted" ]; then
# store handle to var
storage_prim_key=`cat ${tmp_res} | head -n 1 | awk -F ": " '{print $2}'`
fi
fi
}
load_trusted_blob() {
local keypath=$1
local handle=$2
local blob=`cat ${keypath}`
echo "add trusted blob to linux key"
/bin/keyctl add trusted kmk-trusted "load ${blob} keyhandle=${handle}" @u
}
load_encrypted_blob() {
local keypath=$1
local blob=`cat ${keypath}`
echo "add encrypted blob to linux key"
/bin/keyctl add encrypted 1001100110011001 "load ${blob}" @u
}
create_key_master_key() {
local handle=$1
local keypath=$2
if [ -z ${handle} ]; then
echo "err: handle (${handle}) empty"
exit 1
fi
echo "add kmk-trusted from TPM ..."
local kmk=`/bin/keyctl add trusted kmk-trusted "new 32 keyhandle=${handle}" @u`
if [ $? -eq 0 ]; then
echo "pipe kmk-trusted to file ..."
if [ -f "${keypath}" ]; then
echo "warn: ${keypath} already exists"
fi
local res=`/bin/keyctl pipe ${kmk} > ${keypath}`
if [ $? -eq 0 ]; then
echo "revoke kmk-trusted"
/bin/keyctl revoke "${kmk}"
if [ $? -eq 0 ]; then
load_trusted_blob "${keypath}" "${handle}"
fi
fi
fi
}
create_encrypted_key() {
local keypath=$1
echo "add ecryptfs key from trusted kmk ..."
local encrypted=`/bin/keyctl add encrypted 1001100110011001 "new ecryptfs trusted:kmk-trusted 64" @u`
if [ $? -eq 0 ]; then
echo "pipe encrypted key to file ..."
if [ -f "${keypath}" ]; then
echo "warn: ${keypath} already exists"
fi
local res=`/bin/keyctl pipe ${encrypted} > ${keypath}`
if [ $? -eq 0 ]; then
echo "revoke ecryptfs-encrypted key"
/bin/keyctl revoke "${encrypted}"
if [ $? -eq 0 ]; then
load_encrypted_blob "${keypath}"
fi
fi
fi
}
ecryptfs_run() {
kmk_filename="kmk-trusted.blob"
encrypted_filename="ecryptfs-encrypted.blob"
if [ ! -f "$ROOTFS_DIR/etc/keys/${kmk_filename}" ] && [ ! -f "$ROOTFS_DIR/etc/keys/${kmk_filename}" ]; then
echo "*-* create TPM primary key *-*"
create_tpm_prim_key /tmp
echo "*-* persistent handle *-*"
persistent_handle /tmp/key.ctxt
echo "*-* storage primary key: ${storage_prim_key} *-*"
echo "${storage_prim_key}" > "$ROOTFS_DIR/etc/keys/tpm_key_handle"
/bin/keyctl clear @u
/bin/keyctl link @u @s
echo "*-* create_key_master_key *-*"
create_key_master_key ${storage_prim_key} "$ROOTFS_DIR/etc/keys/${kmk_filename}"
echo "*-* create_encrypted_key *-*"
create_encrypted_key "$ROOTFS_DIR/etc/keys/${encrypted_filename}"
elif [ -f "$ROOTFS_DIR/etc/keys/${kmk_filename}" ] && [ -f "$ROOTFS_DIR/etc/keys/${kmk_filename}" ]; then
load_trusted_blob "$ROOTFS_DIR/etc/keys/${kmk_filename}" `cat "$ROOTFS_DIR/etc/keys/tpm_key_handle"`
load_encrypted_blob "$ROOTFS_DIR/etc/keys/${encrypted_filename}"
fi
echo "*-* END *-*"
}