net_snmp: fix CVE-2018-18065

(cherry picked from commit 2f7c24295357240da704cb28c4240ecef36bcd7c)

pkgs/servers/monitoring/net-snmp/CVE-2018-18065.patch

···
+commit 7ffb8e25a0db851953155de91f0170e9bf8c457d
+Author: Robert Story <[e-mail]>
+Date:   Thu Oct 6 10:43:10 2016 -0400
+
+    CHANGES: BUG: 2743: snmpd crashes when receiving a GetNext PDU with multiple Varbinds
+    
+    skip out-of-range varbinds when calling next handler
+
+diff --git a/agent/helpers/table.c b/agent/helpers/table.c
+index 32a08033a..2666638b5 100644
+--- a/agent/helpers/table.c
++++ b/agent/helpers/table.c
+@@ -340,6 +340,8 @@ table_helper_handler(netsnmp_mib_handler *handler,
+             else if (reqinfo->mode == MODE_GET)
+                 table_helper_cleanup(reqinfo, request,
+                                      SNMP_NOSUCHOBJECT);
++            else
++                request->processed = 1; /* skip if next handler called */
+             continue;
+         }
+ 
+@@ -409,6 +411,8 @@ table_helper_handler(netsnmp_mib_handler *handler,
+                 else if (reqinfo->mode == MODE_GET)
+                     table_helper_cleanup(reqinfo, request,
+                                          SNMP_NOSUCHOBJECT);
++                else
++                    request->processed = 1; /* skip if next handler called */
+                 continue;
+             }
+             /*

pkgs/servers/monitoring/net-snmp/default.nix

···
     (fetchAlpinePatch "fix-includes.patch" "0zpkbb6k366qpq4dax5wknwprhwnhighcp402mlm7950d39zfa3m")
     (fetchAlpinePatch "netsnmp-swinst-crash.patch" "0gh164wy6zfiwiszh58fsvr25k0ns14r3099664qykgpmickkqid")
     (fetchAlpinePatch "remove-U64-typedef.patch" "1msxyhcqkvhqa03dwb50288g7f6nbrcd9cs036m9xc8jdgjb8k8j")
+    ./CVE-2018-18065.patch
   ];
 
   preConfigure =