Simplified fix, more clear error message

Author: AlexPeshkoff

src/yvalve/PluginManager.cpp

@@ -79,24 +79,6 @@ namespace
 		file += newExt;
 	}
 
-	// Reject path components in plugin/engine lookup names so DIR_PLUGINS/<name>
-	// cannot escape the plugins directory (path traversal to dlopen).
-	void validatePluginLookupName(const char* pluginName)
-	{
-		if (!pluginName)
-			return;
-
-		for (const char* p = pluginName; *p; ++p)
-		{
-			const unsigned char c = static_cast<unsigned char>(*p);
-			if (c == '/' || c == '\\')
-				(Arg::Gds(isc_random) << "Invalid characters in plugin name").raise();
-		}
-
-		if (strstr(pluginName, ".."))
-			(Arg::Gds(isc_random) << "Invalid characters in plugin name").raise();
-	}
-
 	// Holds a reference to plugins.conf file
 	class StaticConfHolder
 	{
@@ -798,7 +780,11 @@ namespace
 
 		explicit PluginLoadInfo(const char* pluginName)
 		{
-			validatePluginLookupName(pluginName);
+			// check for directories in pluginName
+			PathName path, file;
+			PathUtils::splitLastComponent(path, file, pluginName);
+			if (path.hasData())
+				(Arg::Gds(isc_random) << "Plugin name should not contain directory separator and path component").raise();
 
 			// define default values for plugin ...
 			curModule = fb_utils::getPrefix(IConfigManager::DIR_PLUGINS, pluginName);