agent: Allow to use SETHASH for arbitrary data.
* agent/agent.h (struct server_control_s): Add field digest.data. * agent/gpg-agent.c (agent_deinit_default_ctrl): Free that field. * agent/command.c (reset_notify): Ditto. (start_command_handler): ditto. (cmd_sethash): Add new option --inquire. * agent/call-scd.c (agent_card_pksign): For now return an error if inquire mode was used. * agent/command-ssh.c (ssh_handler_sign_request): Make sure digest.data is cleared. * agent/divert-scd.c (divert_pksign): Implement inquire mode. * agent/pksign.c (agent_pksign_do): Ditto.
This is required to support EdDSA according to RFC8410.
- GnuPG-bug-id: T4888