added context flushes to minimize used TPM resources

update-luks-tpm.sh

@@ -2,12 +2,14 @@
 echo "Updating TPM Policy with current available PCRs"
 
 set +e
-tpm2_evictcontrol -C o -c 0x81000000
+tpm2_evictcontrol -c 0x81000000
 
 set -e
+tpm2_flushcontext -t
 tpm2_createprimary -C e -g sha256 -G ecc256 -c /root/keys/e-primary.context
 tpm2_createpolicy --policy-pcr -l sha256:0,1,2,3,4,5,6,7 -L /root/keys/pcr-policy.digest
 tpm2_create -g sha256 -u /root/keys/obj.pub -r /root/keys/obj.priv -C /root/keys/e-primary.context -L /root/keys/pcr-policy.digest -a "noda|adminwithpolicy|fixedparent|fixedtpm" -i /root/keys/fde-secret.bin
+tpm2_flushcontext -t
 tpm2_load -C /root/keys/e-primary.context -u /root/keys/obj.pub -r /root/keys/obj.priv -c /root/keys/load.context
 tpm2_evictcontrol -C o -c /root/keys/load.context 0x81000000
 # tpm2_unseal -c 0x81000000 -p pcr:sha1:0,1,2,3,4,5,6,7 -o /root/test.bin #proof that the persistence worked