NAME

gfsec-use - Make use of a shared secret

SYNOPSIS

DESCRIPTION

gfsec-use reconstructs a secret file that has been previously split using a tool like gfsplit(1) or the accompanying program gfsec-split(1).

A user-specified command (or a shell) is spawn once the secret has been reconstructed, and the secret file is deleted when the command terminates.

OPTIONS

-h, --help

Display the help message.

-v, --version

Display the version message.

-c, --config file

Specify a configuration file. If the specified file does not exist, a .conf extension is appended to the filename and a corresponding file is searched in $XDG_CONFIG_HOME/gfsecret. When that option is not used, a default configuration $XDG_CONFIG_HOME/gfsecret/default.conf is assumed.

-k, --keep

Do not delete the reconstructed file upon termination of the specified command.

-o, --output file

Write the reconstructed secret in the specified file. This overrides the OUTFILE parameter in the configuration file.

-r, --restore-cmd command

Execute the specified command instead of writing the reconstructed secret to a file. The secret is sent to the command's standard input.

-d, --destroy-cmd command

Execute the specified command instead of deleting the reconstructed secret file upon termination.

CONFIGURATION FILE

A configuration file describes one secret file to reconstruct. Blank lines and lines starting with a # character are ignored.

The following directives can be used:

OUTFILE=file

Specify the file to write the reconstructed secret into.

RESTORE=command

Specify the command to execute once the secret has been reconstructed.

DESTROY=command

Specify the command to execute to destroy the secret upon termination.

MINSHARES=n

Specify the minimal number of shares needed to reconstruct the secret. The default if unspecified is 2.

URI=uri

Specify an URI indicating where to find a share.

Supported URI schemes are:

file:///

Indicates a file on the local filesystem.

uuid://uuid/

Indicates a file on the external volume identified by the specified UUID.

label://label/

Indicates a file on the external volume identified by the specified label.

mtp://serial/

Indicates a file on the MTP device identified by the specified serial number.

Whatever the scheme, the file part of the URI must end with an extension indicating the share number, as generated by gfsplit(1).

The URI may include a share=no parameter, indicating that the corresponding file contains the whole secret and not only a share (in that case, the previous remark about the share number in the extension does not apply).

Another parameter is sha256, which specifies the expected SHA-256 hash value of the share data. If such a parameter is specified, a share will only be used if the data matches the expected hash value.

The gfsec-split(1) program, used to split a file into shares, will automatically generate a suitable configuration file allowing to reconstruct the original file.

EXAMPLE CONFIGURATION FILE

OUTFILE=/home/alice/mysecret
MINSHARES=2
URI=file:///home/alice/.local/share/gfsecret/mysecret.024
URI=label://USBSTICK/mysecret.070?sha256=hex_hash
URI=mtp://RF2GB6X704P/Documents/mysecret.139

REPORTING BUGS

Report bugs to Damien Goutte-Gattat.

SEE ALSO

gfsec-split(1), gfsplit(1), gfcombine(1), libgfshare(3), gfshare(7)

COPYRIGHT

Copyright © 2017 Damien Goutte-Gattat

This program is released under the GNU General Public License. See the COPYING file in the source distribution or http://www.gnu.org/licenses/gpl.html.