.\" SPDX-License-Identifier: MIT
.
.Dd March 11, 2024
.ds doc-volume-operating-system
.Dt ZFS-TPM2-CLEAR-KEY 8
.Os tzpfms 0.4.1-1-gfd16dbb
.
.Sh NAME
.Nm zfs-tpm2-clear-key
.Nd rewrap ZFS dataset key in passsword and clear tzpfms TPM2 metadata
.Sh SYNOPSIS
.Nm
.Ar dataset
.
.Sh DESCRIPTION
After verifying
.Ar dataset
was encrypted with the
.Nm tzpfms
.Sy TPM2
backend:
.Bl -enum -compact -offset 2n -width 2n
.It
performs the equivalent of
.Nm zfs Cm change-key Fl o Li keylocation=prompt Fl o Li keyformat=passphrase Ar dataset ,
.It
frees the sealed key previously used to encrypt
.Ar dataset ,
.It
removes the
.Li xyz.nabijaczleweli:tzpfms.\& Ns Brq Li backend , key
properties from
.Ar dataset .
.El
.Pp
See
.Xr zfs-tpm2-change-key 8
for a detailed description.
.
.\" SPDX-License-Identifier: MIT
.
.Sh ENVIRONMENT VARIABLES
.Bl -tag -compact -width 4n
.It Ev TZPFMS_PASSPHRASE_HELPER
By default, passphrases are prompted for and read in on the standard output and input streams.
If
.Ev TZPFMS_PASSPHRASE_HELPER
is set and nonempty, it will be run via
.Pa /bin/ Ns Nm sh Fl c
to provide each passphrase, instead.
.Pp
The standard output stream of the helper is tied to an anonymous file and used in its entirety as the passphrase, except for a trailing new-line, if any.
The arguments are:
.Bl -tag -compact -offset 2n -width ".Li $1"
.It Li $1
Pre-formatted noun phrase with all the information below, for use as a prompt
.\" Passphrase for tarta-zoot
.\" New passphrase for tarta-zoot (again)
.It Li $2
Either the dataset name or the element of the TPM hierarchy being prompted for
.It Li $3
.Qq new
if this is for a new passphrase, otherwise blank
.It Li $4
.Qq again
if it's the second prompt for that passphrase, otherwise blank
.El
.Pp
If the helper doesn't exist
.Pq the shell exits with Sy 127 ,
a diagnostic is issued and the normal prompt is used as fall-back.
If it fails for any other reason, the prompting is aborted.
.
.
.El
.
.\" SPDX-License-Identifier: MIT
.
.Sh TPM2 back-end configuration
.Ss Environment variables
.Bl -tag -compact -width ".Ev TSS2_LOG"
.It Ev TSS2_LOG
Any of:
.Sy NONE , ERROR , WARNING , INFO , DEBUG , TRACE .
Default:
.Sy WARNING .
.El
.
.Ss TPM selection
The library
.Nm libtss2-tcti-default.so
can be linked to any of the
.Pa libtss2-tcti-*.so
libraries to select the default, otherwise
.Pa /dev/tpmrm0 ,
then
.Pa /dev/tpm0 ,
then
.Pa localhost:2321
will be tried, in order
.Pq see Xr ESYS_CONTEXT 3 .
.
.Ss See also
The tpm2-tss git repository at
.Lk https:/\&/github.com/tpm2-software/tpm2-tss
and the documentation at
.Lk https:/\&/tpm2-tss.readthedocs.io .
.Pp
The TPM 2.0 specifications, mainly at
.Lk https:/\&/trustedcomputinggroup.org/resource/tpm-library-specification/ ,
.Lk https:/\&/trustedcomputinggroup.org/wp-content/uploads/TPM-Rev-2.0-Part-1-Architecture-01.38.pdf ,
and related pages.
.
.\" SPDX-License-Identifier: MIT
.
.Sh SPECIAL THANKS
To all who support further development, in particular:
.Bl -bullet -offset 4n -compact -width "@"
.It
ThePhD
.It
Embark Studios
.It
Jasper Bekkers
.It
EvModder
.El
.
.Sh REPORTING BUGS
.Lk https:/\&/todo.sr.ht/\(tinabijaczleweli/tzpfms
.Pp
.Mt \(tinabijaczleweli/tzpfms@lists.sr.ht ,
archived at
.Lk https:/\&/lists.sr.ht/\(tinabijaczleweli/tzpfms .