Fix cred handle lifetime/expiration confusion

In at least two instances the krb5 cred handle expiration time was misused
as a remaining lifetime.  This is not surprising since the field name is
wrong ("lifetime" not "expiration").  This commit fixes the code, the next
commit will rename the field and change its type from OM_uint32 to time_t.

lib/gssapi/krb5/acquire_cred.c

@@ -41,15 +41,15 @@ __gsskrb5_ccache_lifetime(OM_uint32 *minor_status,
 			  OM_uint32 *lifetime)
 {
     krb5_error_code kret;
-    time_t exp;
+    time_t left;
 
-    kret = krb5_cc_get_lifetime(context, id, &exp);
+    kret = krb5_cc_get_lifetime(context, id, &left);
     if (kret) {
         *minor_status = kret;
         return GSS_S_FAILURE;
     }
 
-    *lifetime = exp;
+    *lifetime = left;
 
     return GSS_S_COMPLETE;
 }
@@ -99,6 +99,7 @@ static OM_uint32 acquire_initiator_cred
     krb5_keytab keytab;
     krb5_error_code kret;
     int try_get_init_creds = 0;
+    time_t now;
 
     keytab = NULL;
     ccache = NULL;
@@ -207,18 +208,24 @@ static OM_uint32 acquire_initiator_cred
     }
 
 found:
+    krb5_timeofday(context, &now);
     ret = __gsskrb5_ccache_lifetime(minor_status,
                                     context,
                                     ccache,
                                     handle->principal,
-                                    &handle->lifetime);
+                                    &left);
     if (ret != GSS_S_COMPLETE) {
         krb5_cc_close(context, ccache);
         goto end;
     }
-    kret = 0;
+    /*
+     * XXX: This is persistent state, and needs to be absolute not
+     * relative time, and so the field name is wrong!
+     */
+    handle->lifetime = now + left;
     handle->ccache = ccache;
     ret = GSS_S_COMPLETE;
+    kret = 0;
 
 end:
     if (cred.client != NULL)

lib/gssapi/krb5/copy_ccache.c

@@ -89,6 +89,8 @@ _gsskrb5_krb5_import_cred(OM_uint32 *minor_status,
     handle->usage = 0;
 
     if (id) {
+	time_t now;
+	OM_uint32 left;
 	char *str;
 
 	handle->usage |= GSS_C_INITIATE;
@@ -116,17 +118,22 @@ _gsskrb5_krb5_import_cred(OM_uint32 *minor_status,
 	    }
 	}
 
+	krb5_timeofday(context, &now);
 	ret = __gsskrb5_ccache_lifetime(minor_status,
 					context,
 					id,
 					handle->principal,
-					&handle->lifetime);
+					&left);
 	if (ret != GSS_S_COMPLETE) {
 	    krb5_free_principal(context, handle->principal);
 	    free(handle);
 	    return ret;
 	}
-
+	/*
+	 * XXX: This is a stored value, hence an absolute time, and the field
+	 * name is misleading.
+	 */
+	handle->lifetime = now + left;
 
 	kret = krb5_cc_get_full_name(context, id, &str);
 	if (kret)