commit bfdc0955657ba83940c63d1d9771b09edc0cb453
Author: Nalin Dahyabhai <nalin@dahyabhai.net>
Date:   Thu Dec 5 13:54:09 2013 -0500

    Flag no-such-keyring errors in get/set-flags ccops
    
    When attempting to use a keyring cache that doesn't exist, return
    KRB5_FCC_NOFILE errors during ccache get/set flags ops, and set an error
    message when we fail to read a principal name, bringing us more in line
    with the behavior we already have when using file-based caches.

diff --git a/src/lib/krb5/ccache/cc_keyring.c b/src/lib/krb5/ccache/cc_keyring.c
index 1a0f1df..421b228 100644
--- a/src/lib/krb5/ccache/cc_keyring.c
+++ b/src/lib/krb5/ccache/cc_keyring.c
@@ -1521,16 +1521,34 @@ krb5_krcc_remove_cred(krb5_context context, krb5_ccache cache,
 static krb5_error_code KRB5_CALLCONV
 krb5_krcc_set_flags(krb5_context context, krb5_ccache id, krb5_flags flags)
 {
+    krb5_krcc_data *d = (krb5_krcc_data *) id->data;
+
     DEBUG_PRINT(("krb5_krcc_set_flags: entered\n"));
 
+    k5_cc_mutex_lock(context, &d->lock);
+    if (!d->cache_id) {
+        k5_cc_mutex_unlock(context, &d->lock);
+        return KRB5_FCC_NOFILE;
+    }
+    k5_cc_mutex_unlock(context, &d->lock);
+
     return KRB5_OK;
 }
 
 static krb5_error_code KRB5_CALLCONV
 krb5_krcc_get_flags(krb5_context context, krb5_ccache id, krb5_flags * flags)
 {
+    krb5_krcc_data *d = (krb5_krcc_data *) id->data;
+
     DEBUG_PRINT(("krb5_krcc_get_flags: entered\n"));
 
+    k5_cc_mutex_lock(context, &d->lock);
+    if (!d->cache_id) {
+        k5_cc_mutex_unlock(context, &d->lock);
+        return KRB5_FCC_NOFILE;
+    }
+    k5_cc_mutex_unlock(context, &d->lock);
+
     *flags = 0;
     return KRB5_OK;
 }
@@ -1707,6 +1725,12 @@ krb5_krcc_retrieve_principal(krb5_context context, krb5_ccache id,
     if (!d->cache_id || !d->princ_id) {
         princ = 0L;
         kret = KRB5_FCC_NOFILE;
+        if (d->name) {
+            krb5_set_error_message(context, kret,
+                                   _("Credentials cache keyring '%s' "
+                                     "not found"),
+                                   d->name);
+        }
         goto errout;
     }