Merge pull request #2 from devanlai/lua-poc

Add support for Lua dissectors
good-tools · Nov 8, 2023 · 06e9cd1 · 06e9cd1
2 parents 25227f5 + 45d23d4
commit 06e9cd1
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Showing 15 changed files with 886 additions and 9 deletions.
diff --git a/README.md b/README.md
@@ -31,6 +31,7 @@ Cross-compiling Wireshark for emscripten/WASM isn't straightforward as it also d
   * `0004-export-wireshark-common.patch` - Expose some headers and objects that are not part of `epan`
   * `0005-force-data-dir.patch` - Force `/wireshark` as the data directory. It is needed for loading preferences, profiles and color filters
   * `0006-threadless-registration.patch` - Makes dissector registrations threadless
+  * `0007-export-lrexlib.patch` - Expose `lrexlib`, which is really a private dependency, but which isn't linked properly if not exported.
 
 ## Usage
 The Wiregasm `Dissect Session` implementation is effectively a tiny subset of `sharkd` APIs.
@@ -84,5 +85,19 @@ sess.delete();
 wg.destroy();
 ```
 
+To add custom Lua dissectors, add your dissectors to the plugins directory
+before initializing wiregasm:
+
+```javascript
+// read lua file from local FS
+const dissector_data = await fs.readFile("path/to/dissector.lua");
+
+// write lua file to the virtual emscripten FS plugin directory
+wg.FS.writeFile("/plugins/dissector.lua", dissector_data)
+
+// initialize and use wiregasm as usual
+wg.init();
+```
+
 ## License
 Wiregasm is a derivative work of the [Wireshark](https://github.com/wireshark/wireshark) project, hence it is licensed under the same [GNU GPLv2](LICENSE) license.
diff --git a/lib/Makefile b/lib/Makefile
@@ -62,8 +62,8 @@ MESON_SETUP = meson setup $(BUILD_DIR) $< --default-library static --prefix $(PR
 MESON_BUILD = meson compile -C $(BUILD_DIR) && meson install -C $(BUILD_DIR)
 
 mostlyclean:
-	rm -rf c-ares ffi gcrypt glib gpg-error pcre wireshark
-	rm -rf .c-ares .ffi .gcrypt .glib .gpg-error .pcre .wireshark
+	rm -rf c-ares ffi gcrypt glib gpg-error lua pcre wireshark
+	rm -rf .c-ares .ffi .gcrypt .glib .gpg-error .lua .pcre .wireshark
 	rm -rf .sum-*
 
 clean: mostlyclean
@@ -253,6 +253,33 @@ glib: glib-$(GLIB_MINOR_VERSION).tar.xz .sum-glib
 	+$(MESON_BUILD)
 	touch $@
 
+#
+# LUA
+#
+LUA_VERSION := 5.2.4
+LUA_URL := https://www.lua.org/ftp/lua-$(LUA_VERSION).tar.gz
+LUA_CHECKSUM := cd77148aba4b707b6c159758b5e8444e04f968092eb98f6b4c405b2fb647e709370d5a8dcf604176101d3407e196a7433b5dcdce4fe9605c76191d3649d61a8c
+# Borrowed from https://github.com/ysugimoto/webassembly-lua/blob/master/Dockerfile
+LUA_CONF := CC='emcc -s WASM=1'
+
+$(TARBALLS)/lua-$(LUA_VERSION).tar.gz:
+	$(call download,$(LUA_URL))
+
+.sum-lua: lua-$(LUA_VERSION).tar.gz
+	$(call checksum,$(LUA_CHECKSUM),$<)
+	touch $@
+
+lua: lua-$(LUA_VERSION).tar.gz .sum-lua
+	$(CLEANUP)
+	tar xzfo $<
+	$(MOVE)
+
+.lua: lua
+	echo "[+] Building Lua"
+	$(MAKE) -C $< clean
+	emmake make -C $< generic INSTALL_TOP=$(PREFIX) install $(LUA_CONF)
+	touch $@
+
 #
 # Wireshark (epan)
 #
@@ -303,9 +330,11 @@ wireshark: wireshark-v$(WIRESHARK_VERSION).tar.bz2 .sum-wireshark
 	$(APPLY) $(PATCHES)/wireshark/0004-export-wireshark-common.patch
 	$(APPLY) $(PATCHES)/wireshark/0005-force-data-dir.patch
 	$(APPLY) $(PATCHES)/wireshark/0006-threadless-registration.patch
+	$(APPLY) $(PATCHES)/wireshark/0007-export-lrexlib.patch
+	$(APPLY) $(PATCHES)/wireshark/0008-export-wslua-headers.patch
 	$(MOVE)
 
-.wireshark: wireshark .c-ares .gcrypt .glib
+.wireshark: wireshark .c-ares .gcrypt .glib .lua
 	echo "[+] Building Wireshark"
 	$(CMAKECLEAN)
 	emcmake cmake -G Ninja -S $< -B $(BUILD_DIR) -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX:STRING=$(PREFIX) -DCMAKE_FIND_ROOT_PATH:STRING=$(PREFIX) $(WIRESHARK_CONF)

diff --git a/lib/wiregasm/bindings.cpp b/lib/wiregasm/bindings.cpp
@@ -7,11 +7,13 @@ using namespace emscripten;
 EMSCRIPTEN_BINDINGS(Wiregasm)
 {
   emscripten::function("init", &wg_init);
+  emscripten::function("reloadLuaPlugins", &wg_reload_lua_plugins);
   emscripten::function("destroy", &wg_destroy);
   emscripten::function("getColumns", &wg_get_columns);
   emscripten::function("upload", &wg_upload_file, allow_raw_pointers());
   emscripten::function("checkFilter", &wg_check_filter);
   emscripten::function("getUploadDirectory", &wg_get_upload_dir);
+  emscripten::function("getPluginsDirectory", &wg_get_plugins_dir);
 }
 
 EMSCRIPTEN_BINDINGS(DissectSession)

diff --git a/lib/wiregasm/ext/mod.js b/lib/wiregasm/ext/mod.js
@@ -15,3 +15,8 @@ if (!Module["handleStatus"])
     console.log(type, status);
   };
 
+// initialize FS with directories
+Module["onRuntimeInitialized"] = () => {
+  Module.FS.mkdir("/plugins");
+  Module.FS.mkdir("/uploads");
+};
diff --git a/lib/wiregasm/meson.build b/lib/wiregasm/meson.build
@@ -22,7 +22,9 @@ foreach d : [
     'gobject-2.0',
     'gmodule-2.0',
     'cares',
-    'gcrypt'
+    'gcrypt',
+    'lua',
+    'lrexlib'
   ]
   dependencies += [ cxx.find_library(d, dirs: [ contrib_lib_dir ], required: true) ]
 endforeach

diff --git a/lib/wiregasm/wiregasm.cpp b/lib/wiregasm/wiregasm.cpp
@@ -1,6 +1,7 @@
 #include "wiregasm.h"
 #include "lib.h"
 #include <wsutil/privileges.h>
+#include <epan/wslua/init_wslua.h>
 
 using namespace std;
 
@@ -21,6 +22,11 @@ string wg_get_upload_dir()
   return string(UPLOAD_DIR);
 }
 
+string wg_get_plugins_dir()
+{
+  return string(get_plugins_dir());
+}
+
 vector<string> wg_get_columns()
 {
   vector<string> v;
@@ -55,6 +61,19 @@ string wg_upload_file(string name, int buffer_ptr, size_t size)
   return ret;
 }
 
+bool wg_reload_lua_plugins()
+{
+  if (!wg_initialized) {
+    return false;
+  }
+
+  wslua_reload_plugins(NULL, NULL);
+
+  on_status(INFO, "Reload complete!");
+
+  return true;
+}
+
 bool wg_init()
 {
   if (wg_initialized)
@@ -65,8 +84,6 @@ bool wg_init()
 
   on_status(INFO, "Initializing..");
 
-  g_mkdir_with_parents(UPLOAD_DIR, 0755);
-
   init_process_policies();
   relinquish_special_privs_perm();
 

diff --git a/lib/wiregasm/wiregasm.h b/lib/wiregasm/wiregasm.h
@@ -77,11 +77,13 @@ struct CheckFilterResponse
 // globals
 
 bool wg_init();
+bool wg_reload_lua_plugins();
 void wg_destroy();
 string wg_upload_file(string name, int buffer_ptr, size_t size);
 vector<string> wg_get_columns();
 CheckFilterResponse wg_check_filter(string filter);
 string wg_get_upload_dir();
+string wg_get_plugins_dir();
 
 class DissectSession
 {

diff --git a/patches/wireshark/0005-force-data-dir.patch b/patches/wireshark/0005-force-data-dir.patch
@@ -18,8 +18,8 @@ index a55086ccbb..6ab8c0585d 100644
 -add_definitions(-DPLUGIN_DIR=\"${CMAKE_INSTALL_PREFIX}/${PLUGIN_INSTALL_LIBDIR}\")
 -add_definitions(-DEXTCAP_DIR=\"${CMAKE_INSTALL_PREFIX}/${EXTCAP_INSTALL_LIBDIR}\")
 -add_definitions(-DDATA_DIR=\"${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_DATADIR}\")
-+add_definitions(-DPLUGIN_DIR=\"/nonexistent/plugins\")
-+add_definitions(-DEXTCAP_DIR=\"/nonexistent/extcap\")
++add_definitions(-DPLUGIN_DIR=\"/plugins\")
++add_definitions(-DEXTCAP_DIR=\"/extcap\")
 +add_definitions(-DDATA_DIR=\"/wireshark\")
 
  add_subdirectory(wmem)

diff --git a/patches/wireshark/0007-export-lrexlib.patch b/patches/wireshark/0007-export-lrexlib.patch
@@ -0,0 +1,34 @@
+From 56160a1aeabb9513c2e93cd49c40f0c56514c58d Mon Sep 17 00:00:00 2001
+From: Devan Lai <[email protected]>
+Date: Sun, 5 Nov 2023 10:31:35 -0800
+Subject: [PATCH] Export lrexlib
+
+---
+ epan/wslua/lrexlib/CMakeLists.txt | 14 ++++++++++++++
+ 1 file changed, 14 insertions(+)
+
+diff --git a/epan/wslua/lrexlib/CMakeLists.txt b/epan/wslua/lrexlib/CMakeLists.txt
+index 1f5f13f278..a60b3f916f 100644
+--- a/epan/wslua/lrexlib/CMakeLists.txt
++++ b/epan/wslua/lrexlib/CMakeLists.txt
+@@ -24,3 +24,17 @@ add_compile_definitions(
+ 	VERSION=\"2.9.1\"
+ 	PCRE2_CODE_UNIT_WIDTH=8
+ )
++
++set_target_properties(lrexlib PROPERTIES
++	PREFIX "lib"
++	LINK_FLAGS "${WS_LINK_FLAGS}"
++	FOLDER "DLLs"
++	INSTALL_RPATH "${LIBRARY_INSTALL_RPATH}"
++)
++
++install(TARGETS lrexlib
++	EXPORT WiresharkTargets
++	RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
++	LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
++	ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
++)
+-- 
+2.34.1
+
diff --git a/patches/wireshark/0008-export-wslua-headers.patch b/patches/wireshark/0008-export-wslua-headers.patch
@@ -0,0 +1,31 @@
+From 1dec7120a409696d1e975a1217958526ce6fc411 Mon Sep 17 00:00:00 2001
+From: Osama Khalid <[email protected]>
+Date: Tue, 7 Nov 2023 11:54:03 -0500
+Subject: [PATCH] Export init_wslua.h header
+
+---
+ epan/wslua/CMakeLists.txt | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/epan/wslua/CMakeLists.txt b/epan/wslua/CMakeLists.txt
+index 39b23d3c5c..10216cc205 100644
+--- a/epan/wslua/CMakeLists.txt
++++ b/epan/wslua/CMakeLists.txt
+@@ -9,6 +9,14 @@
+
+ add_subdirectory(lrexlib)
+
++set(WSLUA_PUBLIC_HEADERS
++	init_wslua.h
++)
++
++install(FILES ${WSLUA_PUBLIC_HEADERS}
++	DESTINATION "${PROJECT_INSTALL_INCLUDEDIR}/epan/wslua"
++)
++
+ set(WSLUA_MODULES
+ 	${CMAKE_CURRENT_SOURCE_DIR}/lua_bitop.c
+ 	${CMAKE_CURRENT_SOURCE_DIR}/wslua_address.c
+-- 
+2.34.1
+