% tpm2_nvwritelock(1) tpm2-tools | General Commands Manual
tpm2_nvwritelock(1) - Lock the Non-Volatile (NV) index for further writes.
tpm2_nvwritelock [OPTIONS] [ARGUMENT]
tpm2_nvwritelock(1) - Lock the Non-Volatile (NV) index for further writes. The lock on the NV index is unlocked when the TPM is restarted and the NV index becomes writable again. The index can be specified as raw handle or an offset value to the nv handle range "TPM2_HR_NV_INDEX".
Specifies the hierarchy used to authorize. Supported options are: * o for TPM_RH_OWNER * p for TPM_RH_PLATFORM *
<num>where a hierarchy handle or nv-index may be used.
When -C isn't explicitly passed the index handle will be used to authorize against the index. The index auth value is set via the -p option to tpm2_nvdefine(1).
Specifies the authorization value for the hierarchy.
Lock all NV indices with attribute TPMA_NV_GLOBALLOCK. This option does not require an NV index or offset as an argument.
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 unless rphash is also required.
File path to record the hash of the response parameters. This is commonly termed as rpHash.
The session created using tpm2_startauthsession. This can be used to specify an auxiliary session for auditing and or encryption/decryption of the parameters.
The name of the NV index that must be provided when only calculating the cpHash without actually dispatching the command to the TPM.
ARGUMENT the command line argument specifies the NV index or offset number.
context object format details the methods for specifying OBJECT.
authorization formatting details the methods for specifying AUTH.
common options collection of common options that provide information many users may expect.
common tcti options collection of options used to configure the various known TCTI modules.
Lock an index
tpm2_nvdefine -C o -s 32 \ -a "ownerread|policywrite|ownerwrite|writedefine" 1 echo "foobar" > nv.writelock tpm2_nvwrite -C o -i nv.writelock 1 tpm2_nvwritelock -C o 1 # fails with "NV access locked" tpm2_nvwrite -C o -i nv.writelock 1
tpm2_nvdefine -C o -s 32 \ -a "ownerread|policywrite|ownerwrite|globallock" 1 tpm2_nvwritelock -C o --global # this command fails with "NV access locked". echo foo | tpm2_nvwrite -C o -i- 1