when the kernel and initramfs are updated. The same key can have many saved
blobs under different PCR values, so multiple boots are easily supported.
+TPM 1.2
+-------
+
By default, trusted keys are sealed under the SRK, which has the default
authorization value (20 zeros). This can be set at takeownership time with the
trouser's utility: "tpm_takeownership -u -z".
+TPM 2.0
+-------
+
+The user must first create a storage key and make it persistent, so the key is
+available after reboot. This can be done using the following commands.
+
+With the IBM TSS 2 stack::
+
+ #> tsscreateprimary -hi o -st
+ Handle 80000000
+ #> tssevictcontrol -hi o -ho 80000000 -hp 81000001
+
+Or with the Intel TSS 2 stack::
+
+ #> tpm2_createprimary --hierarchy o -G rsa2048 -o key.ctxt
+ [...]
+ handle: 0x800000FF
+ #> tpm2_evictcontrol -c key.ctxt -p 0x81000001
+ persistentHandle: 0x81000001
+
Usage::
keyctl add trusted name "new keylen [options]" ring
keyctl print keyid
options:
- keyhandle= ascii hex value of sealing key default 0x40000000 (SRK)
+ keyhandle= ascii hex value of sealing key
+ TPM 1.2: default 0x40000000 (SRK)
+ TPM 2.0: no default; must be passed every time
keyauth= ascii hex auth for sealing key default 0x00...i
(40 ascii zeros)
blobauth= ascii hex auth for sealed data default 0x00...
Where::
- format:= 'default | ecryptfs'
+ format:= 'default | ecryptfs | enc32'
key-type:= 'trusted' | 'user'
Create and save a trusted key named "kmk" of length 32 bytes::
+Note: When using a TPM 2.0 with a persistent key with handle 0x81000001,
+append 'keyhandle=0x81000001' to statements between quotes, such as
+"new 32 keyhandle=0x81000001".
+
$ keyctl add trusted kmk "new 32" @u
440502848
in order to use encrypted keys to mount an eCryptfs filesystem. More details
about the usage can be found in the file
``Documentation/security/keys/ecryptfs.rst``.
+
+Another new format 'enc32' has been defined in order to support encrypted keys
+with payload size of 32 bytes. This will initially be used for nvdimm security
+but may expand to other usages that require 32 bytes payload.