[monitoring-plugins] check_users: Change option for sanity checking ...

[RincewindsHat]

 Module: monitoring-plugins
 Branch: master
 Commit: cff821257bebdbfba87d183726ea9672625c2e77
 Author: RincewindsHat <12514511+rincewinds...@users.noreply.github.com>
   Date: Tue Oct 31 01:47:26 2023 +0100
    URL: 
https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=cff8212

check_users: Change option for sanity checking arguments to avoid segfault

---

 plugins/check_users.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/plugins/check_users.c b/plugins/check_users.c
index 7cf7a2c..916a691 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;
 }