gpg: Allow decryption using PIV cards.

* g10/call-agent.c (struct getattr_one_parm_s): New.
(getattr_one_status_cb): New.
(agent_scd_getattr_one): New.
* g10/pubkey-enc.c (get_it): Allow the standard leading zero byte from
pkcs#1.
* g10/skclist.c (enum_secret_keys): Handle non-OpenPGP cards.

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

1 files changed, 53 insertions, 8 deletions

diff --git a/g10/skclist.c b/g10/skclist.c
index ebbaba254..b4f83ea1a 100644
--- a/g10/skclist.c
+++ b/g10/skclist.c
@@ -340,6 +340,10 @@ enum_secret_keys (ctrl_t ctrl, void **context, PKT_public_key *sk)
     SK_LIST results;
   } *c = *context;
 
+#if MAX_FINGERPRINT_LEN < KEYGRIP_LEN
+# error buffer too short for this configuration
+#endif
+
   if (!c)
     {
       /* Make a new context.  */
@@ -430,17 +434,58 @@ enum_secret_keys (ctrl_t ctrl, void **context, PKT_public_key *sk)
                       xfree (serialno);
                       c->info.fpr2len = 0;
                       err = agent_scd_getattr ("KEY-FPR", &c->info);
+                      if (!err)
+                        {
+                          if (c->info.fpr2len)
+                            {
+                              c->fpr2[0] = '0';
+                              c->fpr2[1] = 'x';
+                              bin2hex (c->info.fpr2, sizeof c->info.fpr2,
+                                       c->fpr2 + 2);
+                              name = c->fpr2;
+                            }
+                        }
+                      else if (gpg_err_code (err) == GPG_ERR_INV_NAME)
+                        {
+                          /* KEY-FPR not supported by the card - get
+                           * the key using the keygrip.  */
+                          char *keyref;
+                          strlist_t kplist, sl;
+                          const char *s;
+                          int i;
+
+                          err = agent_scd_getattr_one ("$ENCRKEYID", &keyref);
+                          if (!err)
+                            {
+                              err = agent_scd_keypairinfo (ctrl, &kplist);
+                              if (!err)
+                                {
+                                  for (sl = kplist; sl; sl = sl->next)
+                                    if ((s = strchr (sl->d, ' '))
+                                        && !strcmp (s+1, keyref))
+                                      break;
+                                  if (sl)
+                                    {
+                                      c->fpr2[0] = '&';
+                                      for (i=1, s=sl->d;
+                                           (*s && *s != ' '
+                                            && i < sizeof c->fpr2 - 3);
+                                           s++, i++)
+                                        c->fpr2[i] = *s;
+                                      c->fpr2[i] = 0;
+                                      name = c->fpr2;
+                                    }
+                                  else /* Restore error.  */
+                                    err = gpg_error (GPG_ERR_INV_NAME);
+                                  free_strlist (kplist);
+                                }
+                            }
+                          xfree (keyref);
+                        }
                       if (err)
-                        log_error ("error retrieving key fingerprint from card: %s\n",
+                        log_error ("error retrieving key from card: %s\n",
                                    gpg_strerror (err));
 
-                      if (c->info.fpr2len)
-                        {
-                          c->fpr2[0] = '0';
-                          c->fpr2[1] = 'x';
-                          bin2hex (c->info.fpr2, sizeof c->info.fpr2,c->fpr2+2);
-                          name = c->fpr2;
-                        }
                       c->sl = c->sl->next;
                     }
                   else