scd: Add an re-select mechanism to switch apps.

* scd/app-common.h (struct app_ctx_s): Add func ptr 'reselect'.
* scd/app-piv.c (do_reselect): New.
(app_select_piv): Move AID constant to file scope.
* scd/app-openpgp.c (do_reselect): New.
(app_select_openpgp): Move AID constant to file scope.
* scd/app.c (apptype_from_name): New.
(check_application_conflict): Check against all apps of the card.
Always set current_apptype.
(select_additional_application): New.
(maybe_switch_app): New.
(app_write_learn_status, app_readcert, app_readkey, app_getattr)
(app_setattr, app_sign, app_auth, app_decipher, app_writecert)
(app_writekey, app_genkey, app_change_pin, app_check_pin): Use it here.
(app_do_with_keygrip): Force reselect on success.
(app_new_register): Move setting of CURRENT_APPTYPE to ...
(select_application): here so that it will be set to the requested
card.
* scd/command.c (open_card_with_request): Select additional
application if possible.
--

Noet that we will likely need to rework this even more so to get well
defined semantics for card access.

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 32 insertions, 2 deletions

diff --git a/scd/app-openpgp.c b/scd/app-openpgp.c
index c301f8218..767f29d26 100644
--- a/scd/app-openpgp.c
+++ b/scd/app-openpgp.c
@@ -59,6 +59,11 @@
 #include "../common/openpgpdefs.h"
 
 
+
+/* The AID of this application.  */
+static char const openpgp_aid[] = { 0xD2, 0x76, 0x00, 0x01, 0x24, 0x01 };
+
+
 /* A table describing the DOs of the card.  */
 static struct {
   int tag;
@@ -5204,12 +5209,35 @@ parse_algorithm_attribute (app_t app, int keyno)
   xfree (relptr);
 }
 
+
+/* Reselect the application.  This is used by cards which support
+ * on-the-fly switching between applications.  */
+static gpg_error_t
+do_reselect (app_t app, ctrl_t ctrl)
+{
+  gpg_error_t err;
+
+  (void)ctrl;
+
+  /* An extra check which should not be necessary because the caller
+   * should have made sure that a re-select is only called for
+   * approriate cards.  */
+  if (app->card->cardtype != CARDTYPE_YUBIKEY)
+    return gpg_error (GPG_ERR_NOT_SUPPORTED);
+
+  /* Note that the card can't cope with P2=0xCO, thus we need to pass
+   * a special flag value. */
+  err = iso7816_select_application (app_get_slot (app),
+                                    openpgp_aid, sizeof openpgp_aid, 0x0001);
+  return err;
+}
+
+
 /* Select the OpenPGP application on the card in SLOT.  This function
    must be used before any other OpenPGP application functions. */
 gpg_error_t
 app_select_openpgp (app_t app)
 {
-  static char const aid[] = { 0xD2, 0x76, 0x00, 0x01, 0x24, 0x01 };
   int slot = app_get_slot (app);
   int rc;
   unsigned char *buffer;
@@ -5218,7 +5246,8 @@ app_select_openpgp (app_t app)
 
   /* Note that the card can't cope with P2=0xCO, thus we need to pass a
      special flag value. */
-  rc = iso7816_select_application (slot, aid, sizeof aid, 0x0001);
+  rc = iso7816_select_application (slot,
+                                   openpgp_aid, sizeof openpgp_aid, 0x0001);
   if (!rc)
     {
       unsigned int manufacturer;
@@ -5353,6 +5382,7 @@ app_select_openpgp (app_t app)
         dump_all_do (slot);
 
       app->fnc.deinit = do_deinit;
+      app->fnc.reselect = do_reselect;
       app->fnc.learn_status = do_learn_status;
       app->fnc.readcert = do_readcert;
       app->fnc.readkey = do_readkey;