[Pkg-gnupg-commit] [gnupg2] 213/241: scd: Fix "Conflicting usage" bug.

[Daniel Kahn Gillmor]

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dkg pushed a commit to branch master
in repository gnupg2.

commit f42c50dbf00c2e6298ca6830cbe6d36805fa54a3
Author: NIIBE Yutaka <gniibe at fsij.org>
Date:   Thu Dec 3 11:26:24 2015 +0900

    scd: Fix "Conflicting usage" bug.
    
    * scd/apdu.c (apdu_close_reader): Call CLOSE_READER method even if we
      got an error from apdu_disconnect.
    * scd/app-common.h (no_reuse): Remove.
    * scd/app.c (application_notify_card_reset): Deallocate APP here.
    (select_application, release_application): Don't use NO_REUSE.
    
    --
    
    Reproducible scenario: Invoke gpg --card-edit session from a terminal.
    Invoke another gpg --card-edit session from another.  Remove a token.
    Insert a token again.  Type RET on both terminals.  One of terminal
    answers "Conflicting usage".
    
    Perhaps, having NO_REUSE field was to avoid race conditions.  Now,
    APP can be safely deallocated by application_notify_card_reset.
    
    Thanks to the2nd.
---
 scd/apdu.c       |  7 +++++--
 scd/app-common.h |  5 -----
 scd/app.c        | 27 ++++++---------------------
 3 files changed, 11 insertions(+), 28 deletions(-)

diff --git a/scd/apdu.c b/scd/apdu.c
index eb3d4b6..95a2561 100644
--- a/scd/apdu.c
+++ b/scd/apdu.c
@@ -3215,9 +3215,12 @@ apdu_close_reader (int slot)
   sw = apdu_disconnect (slot);
   if (sw)
     {
+      /*
+       * When the reader/token was removed it might come here.
+       * It should go through to call CLOSE_READER even if we got an error.
+       */
       if (DBG_READER)
-        log_debug ("leave: apdu_close_reader => 0x%x (apdu_disconnect)\n", sw);
-      return sw;
+        log_debug ("apdu_close_reader => 0x%x (apdu_disconnect)\n", sw);
     }
   if (reader_table[slot].close_reader)
     {
diff --git a/scd/app-common.h b/scd/app-common.h
index 379bcd1..b4bb55b 100644
--- a/scd/app-common.h
+++ b/scd/app-common.h
@@ -47,11 +47,6 @@ struct app_ctx_s {
      operations the particular function pointer is set to NULL */
   unsigned int ref_count;
 
-  /* Flag indicating that a reset has been done for that application
-     and that this context is merely lingering and just should not be
-     reused.  */
-  int no_reuse;
-
   /* Used reader slot. */
   int slot;
 
diff --git a/scd/app.c b/scd/app.c
index 49e08e6..5e6751e 100644
--- a/scd/app.c
+++ b/scd/app.c
@@ -175,9 +175,12 @@ application_notify_card_reset (int slot)
   /* FIXME: We are ignoring any error value here.  */
   lock_reader (slot, NULL);
 
-  /* Mark application as non-reusable.  */
+  /* Release the APP, as it's not reusable any more.  */
   if (lock_table[slot].app)
-    lock_table[slot].app->no_reuse = 1;
+    {
+      deallocate_app (lock_table[slot].app);
+      lock_table[slot].app = NULL;
+    }
 
   /* Deallocate a saved application for that slot, so that we won't
      try to reuse it.  If there is no saved application, set a flag so
@@ -251,16 +254,6 @@ select_application (ctrl_t ctrl, int slot, const char *name, app_t *r_app)
         return gpg_error (GPG_ERR_CONFLICT);
       }
 
-  /* Don't use a non-reusable marked application.  */
-  if (app && app->no_reuse)
-    {
-      unlock_reader (slot);
-      log_info ("lingering application '%s' in use by reader %d"
-                " - can't switch\n",
-                app->apptype? app->apptype:"?", slot);
-      return gpg_error (GPG_ERR_CONFLICT);
-    }
-
   /* If we don't have an app, check whether we have a saved
      application for that slot.  This is useful so that a card does
      not get reset even if only one session is using the card - this
@@ -495,15 +488,7 @@ release_application (app_t app)
 
   if (lock_table[slot].last_app)
     deallocate_app (lock_table[slot].last_app);
-  if (app->no_reuse)
-    {
-      /* If we shall not re-use the application we can't save it for
-         later use. */
-      deallocate_app (app);
-      lock_table[slot].last_app = NULL;
-    }
-  else
-    lock_table[slot].last_app = lock_table[slot].app;
+  lock_table[slot].last_app = lock_table[slot].app;
   lock_table[slot].app = NULL;
   unlock_reader (slot);
 }

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