g10,agent: Support CONFIRM for --delete-key.

* agent/call-pinentry.c (agent_get_confirmation): Add call of
pinentry_loopback_confirm.
(agent_popup_message_start): Likewise.
(agent_popup_message_stop): Return if it's loopback mode.
* agent/command.c (pinentry_loopback_confirm): New.

* g10/call-agent.c (default_inq_cb): Support "CONFIRM" inquery
when PINENTRY_MODE_LOOPBACK mode.
(confirm_status_cb): New.
(agent_delete_key): Supply confirm_status_cb to set the description
string for confirmation.

--

In the Assuan communication, we introduce new interaction:

    [gpg]                            [gpg-agent]
            --- CMD: PKDECRYPT -->
            <-- STATUS: SETDESC "..."
            <-- STATUS: SETOK "..."
            <-- STATUS: SETNOTOK "..."
            <-- INQUERY: CONFIRM 0/1 (0 for display, 1 for user query)
	    --- INQUERY-result: -->
	    <-- RESULT: ...

GnuPG-bug-id: 3465
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>

agent/call-pinentry.c

@@ -1391,6 +1391,9 @@ agent_get_confirmation (ctrl_t ctrl,
       if (ctrl->pinentry_mode == PINENTRY_MODE_CANCEL)
         return gpg_error (GPG_ERR_CANCELED);
 
+      if (ctrl->pinentry_mode == PINENTRY_MODE_LOOPBACK)
+        return pinentry_loopback_confirm (ctrl, desc, 1, ok, notok);
+
       return gpg_error (GPG_ERR_NO_PIN_ENTRY);
     }
 
@@ -1486,7 +1489,15 @@ agent_popup_message_start (ctrl_t ctrl, const char *desc, const char *ok_btn)
   int err;
 
   if (ctrl->pinentry_mode != PINENTRY_MODE_ASK)
-    return gpg_error (GPG_ERR_CANCELED);
+    {
+      if (ctrl->pinentry_mode == PINENTRY_MODE_CANCEL)
+        return gpg_error (GPG_ERR_CANCELED);
+
+      if (ctrl->pinentry_mode == PINENTRY_MODE_LOOPBACK)
+        return pinentry_loopback_confirm (ctrl, desc, 0, ok_btn, NULL);
+
+      return gpg_error (GPG_ERR_NO_PIN_ENTRY);
+    }
 
   rc = start_pinentry (ctrl);
   if (rc)
@@ -1537,6 +1548,9 @@ agent_popup_message_stop (ctrl_t ctrl)
 
   (void)ctrl;
 
+  if (ctrl->pinentry_mode == PINENTRY_MODE_LOOPBACK)
+    return;
+
   if (!popup_tid || !entry_ctx)
     {
       log_debug ("agent_popup_message_stop called with no active popup\n");

agent/command.c

@@ -3680,3 +3680,26 @@ pinentry_loopback(ctrl_t ctrl, const char *keyword,
   assuan_end_confidential (ctx);
   return rc;
 }
+
+/* Helper for the pinentry loopback mode to ask confirmation
+   or just to show message.  */
+gpg_error_t
+pinentry_loopback_confirm (ctrl_t ctrl, const char *desc,
+                           int ask_confirmation,
+                           const char *ok, const char *notok)
+{
+  gpg_error_t err = 0;
+  assuan_context_t ctx = ctrl->server_local->assuan_ctx;
+
+  if (desc)
+    err = print_assuan_status (ctx, "SETDESC", "%s", desc);
+  if (!err && ok)
+    err = print_assuan_status (ctx, "SETOK", "%s", ok);
+  if (!err && notok)
+    err = print_assuan_status (ctx, "SETNOTOK", "%s", notok);
+
+  if (!err)
+    err = assuan_inquire (ctx, ask_confirmation ? "CONFIRM 1" : "CONFIRM 0",
+                          NULL, NULL, 0);
+  return err;
+}

g10/call-agent.c

@@ -41,6 +41,7 @@
 #include "../common/status.h"
 #include "../common/shareddefs.h"
 #include "../common/host2net.h"
+#include "../common/ttyio.h"
 
 #define CONTROL_D ('D' - 'A' + 1)
 
@@ -48,6 +49,13 @@
 static assuan_context_t agent_ctx = NULL;
 static int did_early_card_test;
 
+struct confirm_parm_s
+{
+  char *desc;
+  char *ok;
+  char *notok;
+};
+
 struct default_inq_parm_s
 {
   ctrl_t ctrl;
@@ -57,6 +65,7 @@ struct default_inq_parm_s
     u32 *mainkeyid;
     int pubkey_algo;
   } keyinfo;
+  struct confirm_parm_s *confirm;
 };
 
 struct cipher_parm_s
@@ -136,6 +145,7 @@ default_inq_cb (void *opaque, const char *line)
 {
   gpg_error_t err = 0;
   struct default_inq_parm_s *parm = opaque;
+  const char *s;
 
   if (has_leading_keyword (line, "PINENTRY_LAUNCHED"))
     {
@@ -151,7 +161,7 @@ default_inq_cb (void *opaque, const char *line)
     {
       if (have_static_passphrase ())
         {
-          const char *s = get_static_passphrase ();
+          s = get_static_passphrase ();
           err = assuan_send_data (parm->ctx, s, strlen (s));
         }
       else
@@ -176,6 +186,27 @@ default_inq_cb (void *opaque, const char *line)
           xfree (pw);
         }
     }
+  else if ((s = has_leading_keyword (line, "CONFIRM"))
+           && opt.pinentry_mode == PINENTRY_MODE_LOOPBACK
+           && parm->confirm)
+    {
+      int ask = atoi (s);
+      int yes;
+
+      if (ask)
+        {
+          yes = cpr_get_answer_is_yes (NULL, parm->confirm->desc);
+          if (yes)
+            err = assuan_send_data (parm->ctx, NULL, 0);
+          else
+            err = gpg_error (GPG_ERR_NOT_CONFIRMED);
+        }
+      else
+        {
+          tty_printf ("%s", parm->confirm->desc);
+          err = assuan_send_data (parm->ctx, NULL, 0);
+        }
+    }
   else
     log_debug ("ignoring gpg-agent inquiry '%s'\n", line);
 
@@ -2512,6 +2543,31 @@ agent_export_key (ctrl_t ctrl, const char *hexkeygrip, const char *desc,
 }
 
 
+/* Status callback for handling confirmation.  */
+static gpg_error_t
+confirm_status_cb (void *opaque, const char *line)
+{
+  struct confirm_parm_s *parm = opaque;
+  const char *s;
+
+  if ((s = has_leading_keyword (line, "SETDESC")))
+    {
+      xfree (parm->desc);
+      parm->desc = unescape_status_string (s);
+    }
+  else if ((s = has_leading_keyword (line, "SETOK")))
+    {
+      xfree (parm->ok);
+      parm->ok = unescape_status_string (s);
+    }
+  else if ((s = has_leading_keyword (line, "SETNOTOK")))
+    {
+      xfree (parm->notok);
+      parm->notok = unescape_status_string (s);
+    }
+
+  return 0;
+}
 
 /* Ask the agent to delete the key identified by HEXKEYGRIP.  If DESC
    is not NULL, display DESC instead of the default description
@@ -2524,9 +2580,12 @@ agent_delete_key (ctrl_t ctrl, const char *hexkeygrip, const char *desc,
   gpg_error_t err;
   char line[ASSUAN_LINELENGTH];
   struct default_inq_parm_s dfltparm;
+  struct confirm_parm_s confirm_parm;
 
+  memset (&confirm_parm, 0, sizeof confirm_parm);
   memset (&dfltparm, 0, sizeof dfltparm);
   dfltparm.ctrl = ctrl;
+  dfltparm.confirm = &confirm_parm;
 
   err = start_agent (ctrl, 0);
   if (err)
@@ -2548,7 +2607,10 @@ agent_delete_key (ctrl_t ctrl, const char *hexkeygrip, const char *desc,
             force? " --force":"", hexkeygrip);
   err = assuan_transact (agent_ctx, line, NULL, NULL,
                          default_inq_cb, &dfltparm,
-                         NULL, NULL);
+                         confirm_status_cb, &confirm_parm);
+  xfree (confirm_parm.desc);
+  xfree (confirm_parm.ok);
+  xfree (confirm_parm.notok);
   return err;
 }