Merge pull request #894 from Kraemii/backport-888-21.04

use duplicate host function (backport #888)

CHANGELOG.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - Backport [#853](https://github.com/greenbone/openvas/pull/853)
   - Backport [#862](https://github.com/greenbone/openvas/pull/862)
   - Add `find_all` to eregmatch() nasl function [#875](https://github.com/greenbone/openvas/pull/875)
+- Fix Segmentation fault when freeing hosts and alive hosts [#888](https://github.com/greenbone/openvas/pull/888)
 
 ### Changed
 - Changed defaults for installation locations [#826](https://github.com/greenbone/openvas-scanner/pull/826)

src/attack.c

@@ -1340,6 +1340,7 @@ attack_network (struct scan_globals *globals)
       if (test_alive_hosts_only)
         {
           struct in6_addr tmpaddr;
+          gvm_host_t *buf;
 
           while (1)
             {
@@ -1383,13 +1384,16 @@ attack_network (struct scan_globals *globals)
                 break;
             }
 
-          if (gvm_host_get_addr6 (host, &tmpaddr) == 0)
-            host = gvm_host_find_in_hosts (host, &tmpaddr, hosts);
-
-          if (host)
+          if (host && gvm_host_get_addr6 (host, &tmpaddr) == 0)
             {
-              gvm_hosts_add (alive_hosts_list, host);
+              buf = host;
+              host = gvm_host_find_in_hosts (host, &tmpaddr, hosts);
+              gvm_host_free (buf);
+              buf = NULL;
             }
+
+          if (host)
+            gvm_hosts_add (alive_hosts_list, gvm_duplicate_host (host));
           else
             g_debug ("%s: got NULL host, stop/finish scan", __func__);
         }