한글 디코딩 문제

src/main/java/com/madeu/config/WebConfig.java

@@ -1,14 +1,17 @@
 package com.madeu.config;
 
+import java.io.IOException;
+import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
+
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.Resource;
+import org.springframework.util.StringUtils;
 import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 import org.springframework.web.servlet.resource.PathResourceResolver;
 
-import java.io.IOException;
-
 @Configuration
 public class WebConfig implements WebMvcConfigurer {
     
@@ -19,32 +22,72 @@ public class WebConfig implements WebMvcConfigurer {
     public void addResourceHandlers(ResourceHandlerRegistry registry) {
         registry.addResourceHandler("/cdn/**")
                 .addResourceLocations("file:" + uploadPath + "/")
-                .setCachePeriod(3600) // 1시간 캐싱
+                .setCachePeriod(3600)
                 .resourceChain(true)
                 .addResolver(new PathResourceResolver() {
                     @Override
                     protected Resource getResource(String resourcePath, Resource location) throws IOException {
-                        Resource requestedResource = location.createRelative(resourcePath);
+                        // 1. URL 디코딩
+                        String decodedPath = decodeResourcePath(resourcePath);
                         
-                        // 보안 검증: 허용된 파일 타입만
-                        if (requestedResource.exists() && requestedResource.isReadable() 
-                            && isAllowedResource(requestedResource)) {
+                        // 2. 경로 정규화 (보안 검증)
+                        if (!isValidPath(decodedPath)) {
+                            return null;
+                        }
+                        
+                        // 3. 리소스 찾기
+                        Resource requestedResource = location.createRelative(decodedPath);
+                        
+                        // 4. 존재 여부 및 허용된 파일 타입 검증
+                        if (requestedResource.exists() && 
+                            requestedResource.isReadable() && 
+                            isAllowedResource(requestedResource)) {
                             return requestedResource;
                         }
+                        
                         return null;
                     }
                     
+                    private String decodeResourcePath(String path) {
+                        try {
+                            // UTF-8로 URL 디코딩
+                            return URLDecoder.decode(path, StandardCharsets.UTF_8.name());
+                        } catch (Exception e) {
+                            // 디코딩 실패 시 원본 반환
+                            return path;
+                        }
+                    }
+                    
+                    private boolean isValidPath(String path) {
+                        // 경로 탐색 공격 방지 (../ 등)
+                        if (path.contains("..") || path.contains("./")) {
+                            return false;
+                        }
+                        
+                        // 절대 경로 방지
+                        if (path.startsWith("/") || path.contains(":")) {
+                            return false;
+                        }
+                        
+                        return true;
+                    }
+                    
                     private boolean isAllowedResource(Resource resource) {
                         try {
                             String filename = resource.getFilename();
-                            return filename != null && 
-                                   (filename.toLowerCase().endsWith(".jpg") || 
-                                    filename.toLowerCase().endsWith(".jpeg") || 
-                                    filename.toLowerCase().endsWith(".png") || 
-                                    filename.toLowerCase().endsWith(".gif") || 
-                                    filename.toLowerCase().endsWith(".webp") ||
-                                    filename.toLowerCase().endsWith(".bmp") ||
-                                    filename.toLowerCase().endsWith(".svg"));
+                            if (!StringUtils.hasText(filename)) {
+                                return false;
+                            }
+                            
+                            // 허용된 확장자 체크
+                            String lowerFilename = filename.toLowerCase();
+                            return lowerFilename.endsWith(".jpg") || 
+                                   lowerFilename.endsWith(".jpeg") || 
+                                   lowerFilename.endsWith(".png") || 
+                                   lowerFilename.endsWith(".gif") || 
+                                   lowerFilename.endsWith(".webp") ||
+                                   lowerFilename.endsWith(".bmp") ||
+                                   lowerFilename.endsWith(".svg");
                         } catch (Exception e) {
                             return false;
                         }