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Align RouterFunctions resource handling
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Closes: gh-33434
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@rstoyanchev
rstoyanchev committed Sep 12, 2024
1 parent c77de8a commit d86bf8b
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Showing 2 changed files with 186 additions and 25 deletions.
107 changes: 93 additions & 14 deletions ...ain/java/org/springframework/web/reactive/function/server/PathResourceLookupFunction.java
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright 2002-2022 the original author or authors.
* Copyright 2002-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand All @@ -18,6 +18,7 @@

import java.io.IOException;
import java.io.UncheckedIOException;
import java.net.URLDecoder;
import java.nio.charset.StandardCharsets;
import java.util.function.Function;

Expand All @@ -30,6 +31,7 @@
import org.springframework.util.Assert;
import org.springframework.util.ResourceUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.util.UriUtils;
import org.springframework.web.util.pattern.PathPattern;
import org.springframework.web.util.pattern.PathPatternParser;

Expand Down Expand Up @@ -63,13 +65,17 @@ public Mono<Resource> apply(ServerRequest request) {

pathContainer = this.pattern.extractPathWithinPattern(pathContainer);
String path = processPath(pathContainer.value());
if (path.contains("%")) {
path = StringUtils.uriDecode(path, StandardCharsets.UTF_8);
if (!StringUtils.hasText(path) || isInvalidPath(path)) {
return Mono.empty();
}
if (!StringUtils.hasLength(path) || isInvalidPath(path)) {
if (isInvalidEncodedInputPath(path)) {
return Mono.empty();
}

if (!(this.location instanceof UrlResource)) {
path = UriUtils.decode(path, StandardCharsets.UTF_8);
}

try {
Resource resource = this.location.createRelative(path);
if (resource.isReadable() && isResourceUnderLocation(resource)) {
Expand All @@ -84,7 +90,47 @@ public Mono<Resource> apply(ServerRequest request) {
}
}

private String processPath(String path) {
/**
* Process the given resource path.
* <p>The default implementation replaces:
* <ul>
* <li>Backslash with forward slash.
* <li>Duplicate occurrences of slash with a single slash.
* <li>Any combination of leading slash and control characters (00-1F and 7F)
* with a single "/" or "". For example {@code " / // foo/bar"}
* becomes {@code "/foo/bar"}.
* </ul>
*/
protected String processPath(String path) {
path = StringUtils.replace(path, "\\", "/");
path = cleanDuplicateSlashes(path);
return cleanLeadingSlash(path);
}

private String cleanDuplicateSlashes(String path) {
StringBuilder sb = null;
char prev = 0;
for (int i = 0; i < path.length(); i++) {
char curr = path.charAt(i);
try {
if (curr == '/' && prev == '/') {
if (sb == null) {
sb = new StringBuilder(path.substring(0, i));
}
continue;
}
if (sb != null) {
sb.append(path.charAt(i));
}
}
finally {
prev = curr;
}
}
return (sb != null ? sb.toString() : path);
}

private String cleanLeadingSlash(String path) {
boolean slash = false;
for (int i = 0; i < path.length(); i++) {
if (path.charAt(i) == '/') {
Expand All @@ -94,8 +140,7 @@ else if (path.charAt(i) > ' ' && path.charAt(i) != 127) {
if (i == 0 || (i == 1 && slash)) {
return path;
}
path = slash ? "/" + path.substring(i) : path.substring(i);
return path;
return (slash ? "/" + path.substring(i) : path.substring(i));
}
}
return (slash ? "/" : "");
Expand All @@ -117,6 +162,31 @@ private boolean isInvalidPath(String path) {
return false;
}

/**
* Check whether the given path contains invalid escape sequences.
* @param path the path to validate
* @return {@code true} if the path is invalid, {@code false} otherwise
*/
private boolean isInvalidEncodedInputPath(String path) {
if (path.contains("%")) {
try {
// Use URLDecoder (vs UriUtils) to preserve potentially decoded UTF-8 chars
String decodedPath = URLDecoder.decode(path, StandardCharsets.UTF_8);
if (isInvalidPath(decodedPath)) {
return true;
}
decodedPath = processPath(decodedPath);
if (isInvalidPath(decodedPath)) {
return true;
}
}
catch (IllegalArgumentException ex) {
// May not be possible to decode...
}
}
return false;
}

private boolean isResourceUnderLocation(Resource resource) throws IOException {
if (resource.getClass() != this.location.getClass()) {
return false;
Expand All @@ -142,15 +212,24 @@ else if (resource instanceof ClassPathResource classPathResource) {
return true;
}
locationPath = (locationPath.endsWith("/") || locationPath.isEmpty() ? locationPath : locationPath + "/");
if (!resourcePath.startsWith(locationPath)) {
return false;
}
if (resourcePath.contains("%") && StringUtils.uriDecode(resourcePath, StandardCharsets.UTF_8).contains("../")) {
return false;
}
return true;
return (resourcePath.startsWith(locationPath) && !isInvalidEncodedInputPath(resourcePath));
}

private boolean isInvalidEncodedResourcePath(String resourcePath) {
if (resourcePath.contains("%")) {
// Use URLDecoder (vs UriUtils) to preserve potentially decoded UTF-8 chars...
try {
String decodedPath = URLDecoder.decode(resourcePath, StandardCharsets.UTF_8);
if (decodedPath.contains("../") || decodedPath.contains("..\\")) {
return true;
}
}
catch (IllegalArgumentException ex) {
// May not be possible to decode...
}
}
return false;
}

@Override
public String toString() {
Expand Down
104 changes: 93 additions & 11 deletions ...vc/src/main/java/org/springframework/web/servlet/function/PathResourceLookupFunction.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@

import java.io.IOException;
import java.io.UncheckedIOException;
import java.net.URLDecoder;
import java.nio.charset.StandardCharsets;
import java.util.Optional;
import java.util.function.Function;
Expand All @@ -29,13 +30,16 @@
import org.springframework.util.Assert;
import org.springframework.util.ResourceUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.context.support.ServletContextResource;
import org.springframework.web.util.UriUtils;
import org.springframework.web.util.pattern.PathPattern;
import org.springframework.web.util.pattern.PathPatternParser;

/**
* Lookup function used by {@link RouterFunctions#resources(String, Resource)}.
*
* @author Arjen Poutsma
* @author Rossen Stoyanchev
* @since 5.2
*/
class PathResourceLookupFunction implements Function<ServerRequest, Optional<Resource>> {
Expand All @@ -62,13 +66,17 @@ public Optional<Resource> apply(ServerRequest request) {

pathContainer = this.pattern.extractPathWithinPattern(pathContainer);
String path = processPath(pathContainer.value());
if (path.contains("%")) {
path = StringUtils.uriDecode(path, StandardCharsets.UTF_8);
if (!StringUtils.hasText(path) || isInvalidPath(path)) {
return Optional.empty();
}
if (!StringUtils.hasLength(path) || isInvalidPath(path)) {
if (isInvalidEncodedInputPath(path)) {
return Optional.empty();
}

if (!(this.location instanceof UrlResource)) {
path = UriUtils.decode(path, StandardCharsets.UTF_8);
}

try {
Resource resource = this.location.createRelative(path);
if (resource.isReadable() && isResourceUnderLocation(resource)) {
Expand All @@ -83,7 +91,47 @@ public Optional<Resource> apply(ServerRequest request) {
}
}

private String processPath(String path) {
/**
* Process the given resource path.
* <p>The default implementation replaces:
* <ul>
* <li>Backslash with forward slash.
* <li>Duplicate occurrences of slash with a single slash.
* <li>Any combination of leading slash and control characters (00-1F and 7F)
* with a single "/" or "". For example {@code " / // foo/bar"}
* becomes {@code "/foo/bar"}.
* </ul>
*/
protected String processPath(String path) {
path = StringUtils.replace(path, "\\", "/");
path = cleanDuplicateSlashes(path);
return cleanLeadingSlash(path);
}

private String cleanDuplicateSlashes(String path) {
StringBuilder sb = null;
char prev = 0;
for (int i = 0; i < path.length(); i++) {
char curr = path.charAt(i);
try {
if ((curr == '/') && (prev == '/')) {
if (sb == null) {
sb = new StringBuilder(path.substring(0, i));
}
continue;
}
if (sb != null) {
sb.append(path.charAt(i));
}
}
finally {
prev = curr;
}
}
return sb != null ? sb.toString() : path;
}

private String cleanLeadingSlash(String path) {
boolean slash = false;
for (int i = 0; i < path.length(); i++) {
if (path.charAt(i) == '/') {
Expand All @@ -93,8 +141,7 @@ else if (path.charAt(i) > ' ' && path.charAt(i) != 127) {
if (i == 0 || (i == 1 && slash)) {
return path;
}
path = slash ? "/" + path.substring(i) : path.substring(i);
return path;
return (slash ? "/" + path.substring(i) : path.substring(i));
}
}
return (slash ? "/" : "");
Expand All @@ -113,6 +160,26 @@ private boolean isInvalidPath(String path) {
return path.contains("..") && StringUtils.cleanPath(path).contains("../");
}

private boolean isInvalidEncodedInputPath(String path) {
if (path.contains("%")) {
try {
// Use URLDecoder (vs UriUtils) to preserve potentially decoded UTF-8 chars
String decodedPath = URLDecoder.decode(path, StandardCharsets.UTF_8);
if (isInvalidPath(decodedPath)) {
return true;
}
decodedPath = processPath(decodedPath);
if (isInvalidPath(decodedPath)) {
return true;
}
}
catch (IllegalArgumentException ex) {
// May not be possible to decode...
}
}
return false;
}

private boolean isResourceUnderLocation(Resource resource) throws IOException {
if (resource.getClass() != this.location.getClass()) {
return false;
Expand All @@ -129,6 +196,10 @@ else if (resource instanceof ClassPathResource classPathResource) {
resourcePath = classPathResource.getPath();
locationPath = StringUtils.cleanPath(((ClassPathResource) this.location).getPath());
}
else if (resource instanceof ServletContextResource servletContextResource) {
resourcePath = servletContextResource.getPath();
locationPath = StringUtils.cleanPath(((ServletContextResource) this.location).getPath());
}
else {
resourcePath = resource.getURL().getPath();
locationPath = StringUtils.cleanPath(this.location.getURL().getPath());
Expand All @@ -138,13 +209,24 @@ else if (resource instanceof ClassPathResource classPathResource) {
return true;
}
locationPath = (locationPath.endsWith("/") || locationPath.isEmpty() ? locationPath : locationPath + "/");
if (!resourcePath.startsWith(locationPath)) {
return false;
}
return !resourcePath.contains("%") ||
!StringUtils.uriDecode(resourcePath, StandardCharsets.UTF_8).contains("../");
return (resourcePath.startsWith(locationPath) && !isInvalidEncodedResourcePath(resourcePath));
}

private boolean isInvalidEncodedResourcePath(String resourcePath) {
if (resourcePath.contains("%")) {
// Use URLDecoder (vs UriUtils) to preserve potentially decoded UTF-8 chars...
try {
String decodedPath = URLDecoder.decode(resourcePath, StandardCharsets.UTF_8);
if (decodedPath.contains("../") || decodedPath.contains("..\\")) {
return true;
}
}
catch (IllegalArgumentException ex) {
// May not be possible to decode...
}
}
return false;
}

@Override
public String toString() {
Expand Down

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