1 files changed, 9 insertions, 4 deletions

diff --git a/plugins/check_users.c b/plugins/check_users.c
index 7cf7a2cc..916a691d 100644
--- a/plugins/check_users.c
+++ b/plugins/check_users.c
@@ -227,18 +227,23 @@ process_arguments (int argc, char **argv)
         }
 
         c = optind;
+
         if (warning_range == NULL && argc > c)
                 warning_range = argv[c++];
+
         if (critical_range == NULL && argc > c)
                 critical_range = argv[c++];
 
         /* this will abort in case of invalid ranges */
         set_thresholds (&thlds, warning_range, critical_range);
 
-        if (thlds->warning->end < 0)
-                usage4 (_("Warning threshold must be a positive integer"));
-        if (thlds->critical->end < 0)
-                usage4 (_("Critical threshold must be a positive integer"));
+        if (!thlds->warning) {
+                usage4 (_("Warning threshold must be a valid range expression"));
+        }
+
+        if (!thlds->critical) {
+                usage4 (_("Critical threshold must be a valid range expression"));
+        }
 
         return OK;
 }