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, 14 insertions, 5 deletions

diff --git a/agent/pksign.c b/agent/pksign.c
index 4a5daedb0..3b2fcc4f5 100644
--- a/agent/pksign.c
+++ b/agent/pksign.c
@@ -285,7 +285,8 @@ agent_pksign_do (ctrl_t ctrl, const char *cache_nonce,
                  cache_mode_t cache_mode, lookup_ttl_t lookup_ttl,
                  const void *overridedata, size_t overridedatalen)
 {
-  gcry_sexp_t s_skey = NULL, s_sig = NULL;
+  gcry_sexp_t s_skey = NULL;
+  gcry_sexp_t s_sig  = NULL;
   gcry_sexp_t s_hash = NULL;
   gcry_sexp_t s_pkey = NULL;
   unsigned char *shadow_info = NULL;
@@ -346,10 +347,18 @@ agent_pksign_do (ctrl_t ctrl, const char *cache_nonce,
             is_ECDSA = 1;
         }
 
-      rc = divert_pksign (ctrl, desc_text,
-                          data, datalen,
-                          ctrl->digest.algo,
-                          shadow_info, &buf, &len);
+      {
+        char *desc2 = NULL;
+
+        if (desc_text)
+          agent_modify_description (desc_text, NULL, s_skey, &desc2);
+
+        rc = divert_pksign (ctrl, desc2? desc2 : desc_text,
+                            data, datalen,
+                            ctrl->digest.algo,
+                            shadow_info, &buf, &len);
+        xfree (desc2);
+      }
       if (rc)
         {
           log_error ("smartcard signing failed: %s\n", gpg_strerror (rc));