agent: Prepend the description to a PIN prompt.

* agent/divert-scd.c (has_percent0A_suffix): New.
(getpin_cb): Prepend DESC_TEXT to the prompt.
* agent/findkey.c (modify_description): Rename to ...
(agent_modify_description): this.  MAke global.  Add kludge to remove
empty parentheses from the end.
(agent_key_from_file, agent_delete_key): Adjust for above change.
* agent/pksign.c (agent_pksign_do): Modify DESC_TEXT also when
diverting to a card.
--

Now that we have support for multiple tokens, it is important to show
information on which key has been requested.  Without that it may
happen that the PIN for a wrong card is accidentally entered.

The texts are a bit ugly, because they talk about "passphrase" but
later about entering a PIN.

A quick hack would be to s/passphrase/PIN/ in the description but that
is complicated due to i18n.  Another solution might be never to talk
about PINs in the description but always about "passphrase: and only
use "PIN" or "passphrase" on the left of the entry field.

1 files changed, 50 insertions, 6 deletions

diff --git a/agent/divert-scd.c b/agent/divert-scd.c
index 5ffb7ea54..316440495 100644
--- a/agent/divert-scd.c
+++ b/agent/divert-scd.c
@@ -157,6 +157,18 @@ encode_md_for_card (const unsigned char *digest, size_t digestlen, int algo,
 }
 
 
+/* Return true if STRING ends in "%0A". */
+static int
+has_percent0A_suffix (const char *string)
+{
+  size_t n;
+
+  return (string
+          && (n = strlen (string)) >= 3
+          && !strcmp (string + n - 3, "%0A"));
+}
+
+
 /* Callback used to ask for the PIN which should be set into BUF.  The
    buf has been allocated by the caller and is of size MAXBUF which
    includes the terminating null.  The function should return an UTF-8
@@ -246,7 +258,7 @@ getpin_cb (void *opaque, const char *desc_text, const char *info,
         {
           if (info)
             {
-              char *desc;
+              char *desc, *desc2;
 
               if ( asprintf (&desc,
                              L_("%s%%0A%%0AUse the reader's pinpad for input."),
@@ -254,12 +266,22 @@ getpin_cb (void *opaque, const char *desc_text, const char *info,
                 rc = gpg_error_from_syserror ();
               else
                 {
-                  rc = agent_popup_message_start (ctrl, desc, NULL);
+                  /* Prepend DESC_TEXT to INFO.  */
+                  if (desc_text)
+                    desc2 = strconcat (desc_text,
+                                       has_percent0A_suffix (desc_text)
+                                       ? "%0A" : "%0A%0A",
+                                       desc, NULL);
+                  else
+                    desc2 = NULL;
+                  rc = agent_popup_message_start (ctrl,
+                                                  desc2? desc2:desc, NULL);
+                  xfree (desc2);
                   xfree (desc);
                 }
             }
           else
-            rc = agent_popup_message_start (ctrl, NULL, NULL);
+            rc = agent_popup_message_start (ctrl, desc_text, NULL);
         }
       else
         rc = gpg_error (GPG_ERR_INV_VALUE);
@@ -280,7 +302,19 @@ getpin_cb (void *opaque, const char *desc_text, const char *info,
 
   if (any_flags)
     {
-      rc = agent_askpin (ctrl, info, prompt, again_text, pi, NULL, 0);
+      {
+        char *desc2;
+
+        if (desc_text)
+          desc2 = strconcat (desc_text,
+                             has_percent0A_suffix (desc_text)
+                             ? "%0A" : "%0A%0A",
+                             info, NULL);
+        else
+          desc2 = NULL;
+        rc = agent_askpin (ctrl, desc2, prompt, again_text, pi, NULL, 0);
+        xfree (desc2);
+      }
       again_text = NULL;
       if (!rc && newpin)
         {
@@ -319,14 +353,24 @@ getpin_cb (void *opaque, const char *desc_text, const char *info,
     }
   else
     {
-      char *desc;
+      char *desc, *desc2;
+
       if ( asprintf (&desc,
                      L_("Please enter the PIN%s%s%s to unlock the card"),
                      info? " (":"",
                      info? info:"",
                      info? ")":"") < 0)
         desc = NULL;
-      rc = agent_askpin (ctrl, desc?desc:info, prompt, NULL, pi, NULL, 0);
+      if (desc_text)
+        desc2 = strconcat (desc_text,
+                           has_percent0A_suffix (desc_text)
+                           ? "%0A" : "%0A%0A",
+                           desc, NULL);
+      else
+        desc2 = NULL;
+      rc = agent_askpin (ctrl, desc2? desc2 : desc? desc : info,
+                         prompt, NULL, pi, NULL, 0);
+      xfree (desc2);
       xfree (desc);
     }