spring boot的Thymeleaf模板注入

参考：

• java安全开发之spring boot Thymeleaf模板注入
• https://www.acunetix.com/blog/web-security-zone/exploiting-ssti-in-thymeleaf/
• https://github.com/veracode-research/spring-view-manipulation

场景是view的名字是用户可控时，

实际测试发现跟Spring boot的版本有关，其默认自带的Thymeleaf版本有关。

spring boot:1.5.1.RELEASE spring-boot-starter-thymeleaf:2.1.5
spring boot:2.0.0.RELEASE spring-boot-starter-thymeleaf:3.0.9
spring boot:2.2.0.RELEASE spring-boot-starter-thymeleaf:3.0.11

3.x版本的thymeleaf才受影响。

renderFragment
3.x版本的thymeleaf-spring5是这样的：

            if (!viewTemplateName.contains("::")) {
     
                templateName = viewTemplateName;
                markupSelectors = null;
            } else {
     
                IStandardExpressionParser parser = StandardExpressions.getExpressionParser(configuration);

                FragmentExpression fragmentExpression;
                try {
     
                    fragmentExpression = (FragmentExpression)parser.parseExpression(context, "~{" + viewTemplateName + "}");
                } catch (TemplateProcessingException var25) {
     
                    throw new IllegalArgumentException("Invalid template name specification: '" + viewTemplateName + "'");
                }

而2.x的thymeleaf-spring4是这样的

                Configuration configuration = viewTemplateEngine.getConfiguration();
                ProcessingContext processingContext = new ProcessingContext(context);
                templateCharacterEncoding = getStandardDialectPrefix(configuration);
                StandardFragment fragment = StandardFragmentProcessor.computeStandardFragmentSpec(configuration, processingContext, viewTemplateName, templateCharacterEncoding, "fragment");
                if (fragment == null) {
     
                    throw new IllegalArgumentException("Invalid template name specification: '" + viewTemplateName + "'");
                }