script arguments now get checked before nmap starts scanning

nmap.cc

@@ -659,6 +659,8 @@ int nmap_main(int argc, char *argv[]) {
 		o.chooseScripts(optarg);
 	} else if(strcmp(long_options[option_index].name,"script-args")==0){
 		o.scriptargs=strdup(optarg);
+		if(script_check_args()!=0)
+			fatal("Error parsing --script-args\n");
 	}else if (optcmp(long_options[option_index].name, "script-trace") == 0) {
 		o.scripttrace = 1;
 	} else if (optcmp(long_options[option_index].name, "script-updatedb") == 0){

nse_init.cc

@@ -19,6 +19,7 @@
 
 #include <algorithm>
 int init_setlualibpath(lua_State* l);
+int init_setargs(lua_State *l);
 int init_parseargs(lua_State* l);
 int init_loadfile(lua_State* l, char* filename);
 int init_loaddir(lua_State* l, char* dirname);
@@ -60,8 +61,6 @@ int init_lua(lua_State* l) {
 	SCRIPT_ENGINE_TRY(set_nmaplib(l));
 	lua_setglobal(l, "nmap");
 	SCRIPT_ENGINE_TRY(init_setlualibpath(l));
-	/* add the provided commandline args to the registry */
-	SCRIPT_ENGINE_TRY(init_parseargs(l));
 	return SCRIPT_ENGINE_SUCCESS;
 }
 
@@ -115,12 +114,14 @@ int init_setlualibpath(lua_State* l){
 	lua_pop(l,3);
 	return SCRIPT_ENGINE_SUCCESS;
 }
-
+/* parses the argument provided to --script-args and leaves the processed 
+ * string on the stack, after this it only has to be prepended with 
+ * "<tablename>={" and appended by "}", before it can be called by
+ * luaL_loadbuffer() 
+ */
 int init_parseargs(lua_State* l){
 	//FIXME - free o.script-args after we're finished!!!
-	const char* tmp;
-	std::string processed_args = std::string("nmap.registry.args={");
-	//try the easy way:
+	
 	if(o.scriptargs==NULL){ //if no arguments are provided we're done
 		return SCRIPT_ENGINE_SUCCESS;
 	}
@@ -131,44 +132,58 @@ int init_parseargs(lua_State* l){
 	lua_pushstring(l,o.scriptargs);
 	lua_pushstring(l,"=([^{},$]+)");
 	lua_pushstring(l,"=\"%1\"");
-	if(lua_pcall(l,3,1,0)!=0){
-		error("error parsing --script-args");
-		return SCRIPT_ENGINE_ERROR;
-	}
-	processed_args.append(lua_tostring(l,-1));
+	SCRIPT_ENGINE_TRY(lua_pcall(l,3,1,0));
+	
+	/* copy the result on the bottom of the stack, since this is the part 
+	 * we want to return
+	 */
+	lua_pushvalue(l,-1);
+	lua_insert(l,1);
 	lua_pushstring(l,"%b{}");
 	lua_pushstring(l,"");
-	if(lua_pcall(l,3,1,0)!=0){
-		error("error parsing --script-args");
-		return SCRIPT_ENGINE_ERROR;
-	}
-	tmp=lua_tostring(l,-1);
+	SCRIPT_ENGINE_TRY(lua_pcall(l,3,1,0));
 	lua_getfield(l,-2,"find");
 	lua_pushvalue(l,-2);
 	lua_pushstring(l,"[{}]");
-	if(lua_pcall(l,2,1,0)!=0){
-		error("error parsing --script-args");
-		return SCRIPT_ENGINE_ERROR;
-	}
+	SCRIPT_ENGINE_TRY(lua_pcall(l,2,1,0));
 	if(!lua_isnil(l,-1)){
 		error("unbalanced brackets inside script-options!!\n");
 		return SCRIPT_ENGINE_ERROR;
 	}
-	processed_args.push_back('}');
-	lua_settop(l,0); //clear stack
+	lua_settop(l,1); //clear stack
 
-	tmp = processed_args.c_str();
-	luaL_loadbuffer(l,tmp,strlen(tmp),"Script-Arguments");
+	//luaL_loadbuffer(l,tmp,strlen(tmp),"Script-Arguments");
+	//if(lua_pcall(l,0,0,0)!=0){
+//		error("error loading --script-args: %s",lua_tostring(l,-1));
+//		return SCRIPT_ENGINE_ERROR;
+//	}
+
+	return SCRIPT_ENGINE_SUCCESS;
+}
+/* set the arguments inside the nmap.registry, for use by scripts
+ */
+int init_setargs(lua_State *l){
+	const char *argbuf;
+	size_t argbuflen;
+	if(o.scriptargs==NULL){
+		return SCRIPT_ENGINE_SUCCESS;
+	}
+	/* we'll concatenate the stuff we need to prepend and append to the 
+	 * processed using lua's functionality
+	 */
+	SCRIPT_ENGINE_TRY(init_parseargs(l));
+	lua_pushstring(l,"nmap.registry.args={");
+	lua_insert(l,-2);
+	lua_pushstring(l,"}");
+	lua_concat(l,3);
+	argbuf=lua_tolstring(l,-1,&argbuflen);
+	luaL_loadbuffer(l,argbuf,argbuflen,"Script-Arguments-prerun");
 	if(lua_pcall(l,0,0,0)!=0){
 		error("error loading --script-args: %s",lua_tostring(l,-1));
 		return SCRIPT_ENGINE_ERROR;
 	}
-	//lua_getglobal(l,"nmap");
-	//l_dumpStack(l);
-
 	return SCRIPT_ENGINE_SUCCESS;
 }
-
 /* if there were no command line arguments specifying
  * which scripts should be run, a default script set is
  * chosen

nse_init.h

@@ -15,6 +15,12 @@ extern "C" {
 // opens the standard libraries and the nmap lua library
 int init_lua(lua_State* l);
 
+//takes the script arguments provided to nmap through --script-args and 
+//processes and checks them - leaves the processed string on the stack
+int init_parseargs(lua_State* l);
+//sets the previously parsed args inside nmap.registry
+int init_setargs(lua_State* l);
+
 // you give it a description of scripts to run and it
 // populates the tables 'hosttests' and 'porttests' in l with
 // activation records for tests

nse_main.cc

@@ -105,6 +105,35 @@ finishup:
 	}
 }
 
+//int check_scripts(){
+//}
+/* check the script-arguments provided to nmap (--script-args) before
+ * scanning starts - otherwise the whole scan will run through and be
+ * aborted before script-scanning 
+ */
+int script_check_args(){
+	lua_State* l;
+	const char *argbuf;
+	size_t argbuflen;
+
+	l= lua_open();
+	if(l==NULL){
+		fatal("Error opening lua, for checking arguments\n");
+	}
+	/* set all global libraries (we'll need the string-lib) */
+	SCRIPT_ENGINE_TRY(init_lua(l));
+	SCRIPT_ENGINE_TRY(init_parseargs(l));
+	lua_pushstring(l,"t={");
+	lua_insert(l,-2);
+	lua_pushstring(l,"}");
+	lua_concat(l,3);
+	argbuf=lua_tolstring(l,-1,&argbuflen);
+	luaL_loadbuffer(l,argbuf,argbuflen,"Script-Arguments-prerun");
+	SCRIPT_ENGINE_TRY(lua_pcall(l,0,0,0));
+
+	lua_close(l);
+	return SCRIPT_ENGINE_SUCCESS;
+}
 /* open a lua instance
  * open the lua standard libraries
  * open all the scripts and prepare them for execution
@@ -144,6 +173,11 @@ int script_scan(std::vector<Target*> &targets) {
 	if(status != SCRIPT_ENGINE_SUCCESS) {
 		goto finishup;
 	}
+	//set the arguments - if provided
+	status = init_setargs(l);
+	if(status != SCRIPT_ENGINE_SUCCESS) {
+		goto finishup;
+	}
 
 	status = init_rules(l, o.chosenScripts);
 	if(status != SCRIPT_ENGINE_SUCCESS) {

nse_main.h

@@ -18,5 +18,7 @@ class Target;
 int script_scan(std::vector<Target *> &targets);
 int script_updatedb();
 
+//parses the arguments provided to scripts via nmap's --script-args option 
+int script_check_args();
 #endif