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, 4 insertions, 4 deletions

diff --git a/agent/command-ssh.c b/agent/command-ssh.c
index ca3993321..189acd7f8 100644
--- a/agent/command-ssh.c
+++ b/agent/command-ssh.c
@@ -2430,14 +2430,14 @@ card_key_available (ctrl_t ctrl, const struct card_key_info_s *keyinfo,
     }
 
   hex2bin (keyinfo->keygrip, grip, sizeof (grip));
-  if ( agent_key_available (grip) )
+  if (!ctrl->ephemeral_mode && agent_key_available (ctrl, grip) )
     {
       char *dispserialno;
 
       /* (Shadow)-key is not available in our key storage.  */
       agent_card_getattr (ctrl, "$DISPSERIALNO", &dispserialno,
                           keyinfo->keygrip);
-      err = agent_write_shadow_key (grip, keyinfo->serialno,
+      err = agent_write_shadow_key (ctrl, grip, keyinfo->serialno,
                                     keyinfo->idstr, pkbuf, 0, dispserialno);
       xfree (dispserialno);
       if (err)
@@ -3222,7 +3222,7 @@ ssh_identity_register (ctrl_t ctrl, ssh_key_type_spec_t *spec,
 
   /* Check whether the key is already in our key storage.  Don't do
      anything then besides (re-)adding it to sshcontrol.  */
-  if ( !agent_key_available (key_grip_raw) )
+  if ( !agent_key_available (ctrl, key_grip_raw) )
     goto key_exists; /* Yes, key is available.  */
 
   err = ssh_key_extract_comment (key, &comment);
@@ -3286,7 +3286,7 @@ ssh_identity_register (ctrl_t ctrl, ssh_key_type_spec_t *spec,
 
   /* Store this key to our key storage.  We do not store a creation
    * timestamp because we simply do not know.  */
-  err = agent_write_private_key (key_grip_raw, buffer, buffer_n, 0,
+  err = agent_write_private_key (ctrl, key_grip_raw, buffer, buffer_n, 0,
                                  NULL, NULL, NULL, 0);
   if (err)
     goto out;