From 22189743415af130b0e32a5a13aca1a26f800ead Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Wed, 17 Feb 2021 10:38:58 +0100
Subject: [PATCH] dnsdist: Prevent a crash with DynBPF objects in client mode

---
 pdns/dnsdist-lua-bindings.cc | 8 ++++++++
 pdns/dnsdist-lua.cc          | 3 +++
 2 files changed, 11 insertions(+)

diff --git a/pdns/dnsdist-lua-bindings.cc b/pdns/dnsdist-lua-bindings.cc
index 8be20c5965..5f04fd5e8c 100644
--- a/pdns/dnsdist-lua-bindings.cc
+++ b/pdns/dnsdist-lua-bindings.cc
@@ -448,6 +448,10 @@ void setupLuaBindings(LuaContext& luaCtx, bool client)
     });
 
     luaCtx.registerFunction<void(std::shared_ptr<DynBPFFilter>::*)(boost::variant<std::string, std::vector<std::pair<int, std::string>>>)>("excludeRange", [](std::shared_ptr<DynBPFFilter> dbpf, boost::variant<std::string, std::vector<std::pair<int, std::string>>> ranges) {
+      if (!dbpf) {
+        return;
+      }
+
       if (ranges.type() == typeid(std::vector<std::pair<int, std::string>>)) {
         for (const auto& range : *boost::get<std::vector<std::pair<int, std::string>>>(&ranges)) {
           dbpf->excludeRange(Netmask(range.second));
@@ -459,6 +463,10 @@ void setupLuaBindings(LuaContext& luaCtx, bool client)
     });
 
     luaCtx.registerFunction<void(std::shared_ptr<DynBPFFilter>::*)(boost::variant<std::string, std::vector<std::pair<int, std::string>>>)>("includeRange", [](std::shared_ptr<DynBPFFilter> dbpf, boost::variant<std::string, std::vector<std::pair<int, std::string>>> ranges) {
+      if (!dbpf) {
+        return;
+      }
+
       if (ranges.type() == typeid(std::vector<std::pair<int, std::string>>)) {
         for (const auto& range : *boost::get<std::vector<std::pair<int, std::string>>>(&ranges)) {
           dbpf->includeRange(Netmask(range.second));
diff --git a/pdns/dnsdist-lua.cc b/pdns/dnsdist-lua.cc
index 070f87b59a..7535c66ced 100644
--- a/pdns/dnsdist-lua.cc
+++ b/pdns/dnsdist-lua.cc
@@ -1642,6 +1642,9 @@ static void setupLuaConfig(LuaContext& luaCtx, bool client, bool configCheck)
     });
 
   luaCtx.writeFunction("addBPFFilterDynBlocks", [](const std::unordered_map<ComboAddress,unsigned int, ComboAddress::addressOnlyHash, ComboAddress::addressOnlyEqual>& m, std::shared_ptr<DynBPFFilter> dynbpf, boost::optional<int> seconds, boost::optional<std::string> msg) {
+      if (!dynbpf) {
+        return;
+      }
       setLuaSideEffect();
       struct timespec until, now;
       clock_gettime(CLOCK_MONOTONIC, &now);
-- 
2.47.2