agent: Support pinentries with integrated repeat passphrase feature.

* agent/agent.h (struct pin_entry_info_s): Add fields repeat_okay and
with_repeat.
* agent/call-pinentry.c (close_button_status_cb): Rewrite and check
for PIN_REPEAT.  Change users to check only the relevant bit.
(agent_askpin): Support repeat logic of new Pinentries.

* agent/command-ssh.c (ssh_identity_register): Use the new repeat
feature.
* agent/genkey.c (agent_ask_new_passphrase): Ditto.

--

If we need to confirm a passphrase entry (e.g. for new passphrase) we
set a flag into the pinentry info block.  The we try to use the new
pinentry command SETREPEATERROR; if that fails, we continue as usual.
If that succeeds we ask the pinentry to show the repeat (confirmation)
prompt and on successful return we set another flag in the pinentry
info block so that the caller can skip its own confirmation check. A
new status line from the pinentry indicates that the feature is
actually supported (it may not be supported on certain systems for
example when using the ncurses backend).

Signed-off-by: Werner Koch <wk@gnupg.org>

4 files changed, 52 insertions, 19 deletions

diff --git a/agent/agent.h b/agent/agent.h
index 7342475e7..b80c6a05c 100644
--- a/agent/agent.h
+++ b/agent/agent.h
@@ -220,6 +220,8 @@ struct pin_entry_info_s
   int max_tries;  /* max. number of allowed tries.  */
   int failed_tries; /* Number of tries so far failed.  */
   int with_qualitybar; /* Set if the quality bar should be displayed.  */
+  int with_repeat;  /* Request repetition of the passphrase.  */
+  int repeat_okay;  /* Repetition worked. */
   int (*check_cb)(struct pin_entry_info_s *); /* CB used to check the PIN */
   void *check_cb_arg;  /* optional argument which might be of use in the CB */
   const char *cb_errtext; /* used by the cb to display a specific error */
diff --git a/agent/call-pinentry.c b/agent/call-pinentry.c
index 126d6968b..e5977ad6a 100644
--- a/agent/call-pinentry.c
+++ b/agent/call-pinentry.c
@@ -682,23 +682,23 @@ setup_qualitybar (void)
 }
 
 
-/* Check the button_info line for a close action.  */
+/* Check the button_info line for a close action.  Also check for the
+   PIN_REPEATED flag.  */
 static gpg_error_t
 close_button_status_cb (void *opaque, const char *line)
 {
-  int *flag = opaque;
-  const char *keyword = line;
-  int keywordlen;
+  unsigned int *flag = opaque;
+  const char *args;
 
-  for (keywordlen=0; *line && !spacep (line); line++, keywordlen++)
-    ;
-  while (spacep (line))
-    line++;
-  if (keywordlen == 11 && !memcmp (keyword, "BUTTON_INFO", keywordlen))
+  if ((args = has_leading_keyword (line, "BUTTON_INFO")))
     {
-      if ( !strcmp (line, "close") )
+      if (!strcmp (args, "close"))
         *flag = 1;
     }
+  else if (has_leading_keyword (line, "PIN_REPEATED"))
+    {
+      *flag |= 256;
+    }
 
   return 0;
 }
@@ -721,7 +721,7 @@ agent_askpin (ctrl_t ctrl,
   const char *errtext = NULL;
   int is_pin = 0;
   int saveflag;
-  int close_button;
+  unsigned int close_button;
 
   if (opt.batch)
     return 0; /* fixme: we should return BAD PIN */
@@ -806,6 +806,18 @@ agent_askpin (ctrl_t ctrl,
         return unlock_pinentry (rc);
     }
 
+  if (pininfo->with_repeat)
+    {
+      snprintf (line, DIM(line)-1, "SETREPEATERROR %s",
+                _("does not match - try again"));
+      line[DIM(line)-1] = 0;
+      rc = assuan_transact (entry_ctx, line,
+                            NULL, NULL, NULL, NULL, NULL, NULL);
+      if (rc)
+        pininfo->with_repeat = 0; /* Pinentry does not support it.  */
+    }
+  pininfo->repeat_okay = 0;
+
   for (;pininfo->failed_tries < pininfo->max_tries; pininfo->failed_tries++)
     {
       memset (&parm, 0, sizeof parm);
@@ -828,6 +840,16 @@ agent_askpin (ctrl_t ctrl,
           errtext = NULL;
         }
 
+      if (pininfo->with_repeat)
+        {
+          snprintf (line, DIM(line)-1, "SETREPEAT %s", _("Repeat:"));
+          line[DIM(line)-1] = 0;
+          rc = assuan_transact (entry_ctx, line,
+                                NULL, NULL, NULL, NULL, NULL, NULL);
+          if (rc)
+            return unlock_pinentry (rc);
+        }
+
       saveflag = assuan_get_flag (entry_ctx, ASSUAN_CONFIDENTIAL);
       assuan_begin_confidential (entry_ctx);
       close_button = 0;
@@ -842,9 +864,10 @@ agent_askpin (ctrl_t ctrl,
           && gpg_err_code (rc) == GPG_ERR_ASS_CANCELED)
         rc = gpg_err_make (gpg_err_source (rc), GPG_ERR_CANCELED);
 
+
       /* Change error code in case the window close button was clicked
          to cancel the operation.  */
-      if (close_button && gpg_err_code (rc) == GPG_ERR_CANCELED)
+      if ((close_button & 1) && gpg_err_code (rc) == GPG_ERR_CANCELED)
         rc = gpg_err_make (gpg_err_source (rc), GPG_ERR_FULLY_CANCELED);
 
       if (gpg_err_code (rc) == GPG_ERR_ASS_TOO_MUCH_DATA)
@@ -881,7 +904,11 @@ agent_askpin (ctrl_t ctrl,
         }
 
       if (!errtext)
-        return unlock_pinentry (0); /* okay, got a PIN or passphrase */
+        {
+          if (pininfo->with_repeat && (close_button & 256))
+            pininfo->repeat_okay = 1;
+          return unlock_pinentry (0); /* okay, got a PIN or passphrase */
+        }
     }
 
   return unlock_pinentry (gpg_error (pininfo->min_digits? GPG_ERR_BAD_PIN
@@ -902,7 +929,7 @@ agent_get_passphrase (ctrl_t ctrl,
   char line[ASSUAN_LINELENGTH];
   struct entry_parm_s parm;
   int saveflag;
-  int close_button;
+  unsigned int close_button;
 
   *retpass = NULL;
   if (opt.batch)
@@ -991,7 +1018,7 @@ agent_get_passphrase (ctrl_t ctrl,
     rc = gpg_err_make (gpg_err_source (rc), GPG_ERR_CANCELED);
   /* Change error code in case the window close button was clicked
      to cancel the operation.  */
-  if (close_button && gpg_err_code (rc) == GPG_ERR_CANCELED)
+  if ((close_button & 1) && gpg_err_code (rc) == GPG_ERR_CANCELED)
     rc = gpg_err_make (gpg_err_source (rc), GPG_ERR_FULLY_CANCELED);
 
   if (rc)
diff --git a/agent/command-ssh.c b/agent/command-ssh.c
index 54273239f..f3ef30c15 100644
--- a/agent/command-ssh.c
+++ b/agent/command-ssh.c
@@ -3104,6 +3104,7 @@ ssh_identity_register (ctrl_t ctrl, ssh_key_type_spec_t *spec,
   pi2 = pi + (sizeof *pi + 100 + 1);
   pi->max_length = 100;
   pi->max_tries = 1;
+  pi->with_repeat = 1;
   pi2->max_length = 100;
   pi2->max_tries = 1;
   pi2->check_cb = reenter_compare_cb;
@@ -3115,8 +3116,9 @@ ssh_identity_register (ctrl_t ctrl, ssh_key_type_spec_t *spec,
   if (err)
     goto out;
 
-  /* Unless the passphrase is empty, ask to confirm it.  */
-  if (pi->pin && *pi->pin)
+  /* Unless the passphrase is empty or the pinentry told us that
+     it already did the repetition check, ask to confirm it.  */
+  if (pi->pin && *pi->pin && !pi->repeat_okay)
     {
       err = agent_askpin (ctrl, description2, NULL, NULL, pi2);
       if (err == -1)
diff --git a/agent/genkey.c b/agent/genkey.c
index 9918c12e7..91917f77b 100644
--- a/agent/genkey.c
+++ b/agent/genkey.c
@@ -363,6 +363,7 @@ agent_ask_new_passphrase (ctrl_t ctrl, const char *prompt,
   pi->max_length = 100;
   pi->max_tries = 3;
   pi->with_qualitybar = 1;
+  pi->with_repeat = 1;
   pi2->max_length = 100;
   pi2->max_tries = 3;
   pi2->check_cb = reenter_compare_cb;
@@ -379,8 +380,9 @@ agent_ask_new_passphrase (ctrl_t ctrl, const char *prompt,
           pi2->failed_tries = 0;
           goto next_try;
         }
-      /* Unless the passphrase is empty, ask to confirm it.  */
-      if (pi->pin && *pi->pin)
+      /* Unless the passphrase is empty or the pinentry told us that
+         it already did the repetition check, ask to confirm it.  */
+      if (pi->pin && *pi->pin && !pi->repeat_okay)
         {
           err = agent_askpin (ctrl, text2, NULL, NULL, pi2);
           if (err == -1)