v2 - avoid crash in topology plugin when host list contains host with no hostname

ticket #5928

prevent a crash when dereferncing a NULL hostnam, log an error to help debugging
fix an incorrect order of statement when freeing a host list

Reviewed-By: Thierry Bordaz <tbordaz@redhat.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/daemons/ipa-slapi-plugins/topology/topology_cfg.c b/daemons/ipa-slapi-plugins/topology/topology_cfg.c
index 3ca61a8ea..23b8eddfb 100644
--- a/daemons/ipa-slapi-plugins/topology/topology_cfg.c
+++ b/daemons/ipa-slapi-plugins/topology/topology_cfg.c
@@ -452,6 +452,15 @@ ipa_topo_cfg_host_find(TopoReplica *tconf, char *findhost, int lock)
 
     if (lock) slapi_lock_mutex(tconf->repl_lock);
     for (host=tconf->hosts;host;host=host->next) {
+        if (host->hostname == NULL) {
+            /* this check is done to avoid a crash,
+             * for which the root cause is not yet known.
+             * Avoid the crash and log an error
+             */
+            slapi_log_error(SLAPI_LOG_FATAL, IPA_TOPO_PLUGIN_SUBSYSTEM,
+                            "ipa_topo_cfg_host_find: found a NULL hostname in host list\n");
+            continue;
+        }
         if (!strcasecmp(host->hostname,findhost)) {
            break;
         }
@@ -849,8 +858,8 @@ ipa_topo_cfg_replica_free(TopoReplica *tconf)
         while (host) {
             host_next = host->next;
             slapi_ch_free_string(&host->hostname);
-            host = host_next;
             slapi_ch_free((void **)&host);
+            host = host_next;
         }
         slapi_ch_free((void **)&tconf);
     }