agent: Add "ephemeral" Assuan option.

* agent/agent.h (struct ephemeral_private_key_s): New.
(struct server_control_s): Add ephemeral_mode and ephemeral_keys.
(GENKEY_FLAG_NO_PROTECTION, GENKEY_FLAG_PRESET): New.
* agent/genkey.c (clear_ephemeral_keys): New.
(store_key): Add arg ctrl and implement ephemeral_mode.  Change all
callers.
(agent_genkey): Replace args no_protection and preset by a generic new
flags arg.
* agent/findkey.c (wipe_and_fclose): New.
(agent_write_private_key): Add arg ctrl and implement ephemeral_mode.
Change all callers.
(agent_update_private_key): Ditto
(read_key_file): Ditto.
(agent_key_available): Ditto.
* agent/command-ssh.c (card_key_available): Do not update display s/n
in ephemeral mode.  This is however enver triggred.
* agent/gpg-agent.c (agent_deinit_default_ctrl): Cleanup ephemeral
keys.
* agent/command.c (cmd_genkey): Use the new flags instead of separate
vars.
(cmd_readkey): Create a shadow key only in non-ephemeral_mode.
(cmd_getinfo): Add sub-command "ephemeral".
(option_handler): Add option "ephemeral".
--

The idea here that a session can be switched in an ephemeral mode
which does not store or read keys from disk but keeps them local to
the session.

GnuPG-bug-id: 6944

1 files changed, 3 insertions, 2 deletions

diff --git a/agent/pksign.c b/agent/pksign.c
index a7b5c579f..322918969 100644
--- a/agent/pksign.c
+++ b/agent/pksign.c
@@ -371,13 +371,14 @@ agent_pksign_do (ctrl_t ctrl, const char *cache_nonce,
               goto leave;
             }
 
-          if (keyref)
+          if (keyref && !ctrl->ephemeral_mode)
             {
               char *dispserialno;
 
               agent_card_getattr (ctrl, "$DISPSERIALNO", &dispserialno,
                                   hexgrip);
-              agent_write_shadow_key (ctrl->keygrip, serialno, keyref, pkbuf,
+              agent_write_shadow_key (ctrl,
+                                      ctrl->keygrip, serialno, keyref, pkbuf,
                                       0, dispserialno);
               xfree (dispserialno);
             }