代码安全静态分析（3）-污点分析

class TaintAnalyzer:    def __init__(self):        self.tainted_vars = set()    def analyze(self, ast):        self.visit(ast)    def visit_Assign(self, node):        if node.value.type == 'UserInput':            self.tainted_vars.add(node.target.name)        else:            self.visit(node.value)    def visit_Variable(self, node):        if node.name in self.tainted_vars:            self.report_potential_vulnerability(node.name)    def visit_Call(self, node):        for arg in node.args:            self.visit(arg)        if node.func.name == 'SensitiveOperation':            for arg in node.args:                if arg.name in self.tainted_vars:                    self.report_potential_vulnerability(arg.name)    def report_potential_vulnerability(self, var_name):        print(f'Potential vulnerability: Tainted data "{var_name}" reaches a sensitive operation.')# 示例代码code = """x = input('Enter data:')y = x + 1print(y)z = query_database(x)"""ast = parse(code)analyzer = TaintAnalyzer()analyzer.analyze(ast)

class TaintAnalyzer:    def __init__(self):        self.tainted_vars = set()        self.sinks = ['os.system', 'subprocess.call']    def analyze(self, source_code):        # 解析代码，构建抽象语法树（AST）        ast = parse(source_code)        self.visit(ast)    def visit_Call(self, node):        # 检查是否调用了潜在的RCE函数        if node.func.id in self.sinks:            # 追踪参数的来源            for arg in node.args:                self.check_arg_taint(arg)    def check_arg_taint(self, arg):        # 检查参数是否被标记为污点        if isinstance(arg, Name) and arg.id in self.tainted_vars:            print(f"Potential RCE vulnerability found: Tainted variable '{arg.id}' used in dangerous function call.")    def visit_Assign(self, node):        # 检查变量赋值是否来自用户输入等污点源        if isinstance(node.value, Call) and 'input' in node.value.func.id:            self.tainted_vars.add(node.target.id)# 示例代码code = """import osimport subprocessdef main():    user_input = input("Enter command: ")    result = os.system(user_input)  # 污点源到汇聚点的传播    return resultif __name__ == "__main__":    main()"""analyzer = TaintAnalyzer()analyzer.analyze(code)

# taint_analyzer.pyclass TaintAnalyzer:    def __init__(self):        self.files = {}        self.tainted_vars = set()    def analyze(self, project_path):        # 解析项目中的所有文件        for filename in os.listdir(project_path):            file_path = os.path.join(project_path, filename)            if os.path.isfile(file_path):                self.files[filename] = self._parse_file(file_path)    def _parse_file(self, file_path):        # 解析单个文件并构建AST        # 这里应该使用具体的解析库，如Python的ast模块        pass    def _propagate_taints(self, var_name, source_file, target_file):        # 追踪变量在文件间的传播        if source_file in self.files and target_file in self.files:            source_ast = self.files[source_file]            target_ast = self.files[target_file]            # 在这里实现污点传播的逻辑            pass    def check_for_vulnerabilities(self):        # 检查是否存在安全漏洞        for var_name in self.tainted_vars:            for source_file, _ in self.files.items():                for target_file, _ in self.files.items():                    if var_name in source_file and self._is_sink(target_file):                        self._propagate_taints(var_name, source_file, target_file)    def _is_sink(self, file_name):        # 检查文件是否包含潜在的污点汇聚点        # 这里应该根据具体的污点汇聚点定义来实现        return False# main.pyif __name__ == "__main__":    project_path = "/path/to/project"    analyzer = TaintAnalyzer()    analyzer.analyze(project_path)    analyzer.check_for_vulnerabilities()