% tpm2_flushcontext(1) tpm2-tools | General Commands Manual
NAME
tpm2_flushcontext(1) - Remove a specified handle, or all contexts associated with a transient object, loaded session or saved session from the TPM.
SYNOPSIS
tpm2_flushcontext [OPTIONS] [ARGUMENT]
DESCRIPTION
tpm2_flushcontext(1) - Remove a specified handle, or all contexts associated with a transient object, loaded session or saved session from the TPM. The object to be flushed is specified as the first argument to the tool and is in one of the following forms: - The handle of the object to be flushed from the TPM. Must be a valid handle number. - Flush a session via a session file. A session file is generated from tpm2_startauthsession(1)'s -S option.
OPTIONS
-
-t, --transient-object:
Remove all transient objects.
-
-l, --loaded-session:
Remove all loaded sessions.
-
-s, --saved-session:
Remove all saved sessions.
-
ARGUMENT the command line argument specifies the OBJECT to be removed from the TPM resident memory.
-
--cphash=FILE
File path to record the hash of the command parameters. This is commonly termed as cpHash. NOTE: When this option is selected, The tool will not actually execute the command, it simply returns a cpHash.
EXAMPLES
Flushing a Transient Object
Typically, when using the TPM, the interactions occur through a resource manager, like tpm2-abrmd(8). When the process exits, transient object handles are flushed. Thus, flushing transient objects through the command line is not required. However, when interacting with the TPM directly, this scenario is possible. The below example assumes direct TPM access not brokered by a resource manager. Specifically we will use the simulator.
tpm2_createprimary -Tmssim -c primary.ctx
tpm2_getcap -T mssim handles-transient
- 0x80000000
tpm2_flushcontext -T mssim 0x80000000
Flush All the Transient Objects
tpm2_flushcontext \--transient-object
Flush a Session
tpm2_startauthsession -S session.dat
tpm2_flushcontext session.dat