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fix(docs): prevent path traversal in /docs static handler#80

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fix(docs): prevent path traversal in /docs static handler #80

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20 changes: 16 additions & 4 deletions backend/src/index.ts
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -15,6 +15,7 @@ async function exists(path: string): Promise<boolean> {
}
}
import { join } from "node:path";
import { resolvePathWithinBase } from "@/utils/safePath";
import { routes } from "@/api";
import { metricsApi } from "@/api/metrics";
import { loggerPlugin } from "@/plugins/loggerPlugin";
Expand DownExpand Up@@ -91,7 +92,12 @@ async function docsPlugin(dir: string) {
// Handle TanStack Start's __tsr static server function cache requests
// These are requested from root path, not /docs/
.get("/__tsr/*", async ({ path, status }) => {
const response = await serveStaticFile(join(dir, path));
const filePath = resolvePathWithinBase(dir, path);
if (!filePath) {
return status(404);
}

const response = await serveStaticFile(filePath);
return response || status(404);
})
.get("/docs", ({ status }) => {
Expand All@@ -107,7 +113,10 @@ async function docsPlugin(dir: string) {
return status(404);
}
const subPath = path.replace("/docs", "");
const exactPath = join(dir, subPath);
const exactPath = resolvePathWithinBase(dir, subPath);
if (!exactPath) {
return status(404);
}

// Try to serve as static file
const staticResponse = await serveStaticFile(exactPath);
Expand All@@ -116,8 +125,11 @@ async function docsPlugin(dir: string) {
}

// Check if there's a specific HTML file for this path (directory with index.html)
const specificHtmlPath = join(dir, subPath, "index.html");
if (await exists(specificHtmlPath)) {
const specificHtmlPath = resolvePathWithinBase(
dir,
join(subPath, "index.html"),
);
if (specificHtmlPath && (await exists(specificHtmlPath))) {
const html = await readFile(specificHtmlPath, "utf-8");
return new Response(html, {
headers: { "Content-Type": "text/html" },
Expand Down
27 changes: 27 additions & 0 deletions backend/src/utils/safePath.test.ts
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
import { describe, expect, test } from "bun:test";
import { resolve } from "node:path";
import { resolvePathWithinBase } from "./safePath";

describe("resolvePathWithinBase", () => {
const baseDir = resolve("/tmp/docs-base");

test("resolves nested relative paths inside the base directory", () => {
expect(resolvePathWithinBase(baseDir, "/assets/app.js")).toBe(
resolve(baseDir, "assets/app.js"),
);
});

test("keeps base directory requests inside the base directory", () => {
expect(resolvePathWithinBase(baseDir, "/")).toBe(baseDir);
});

test("rejects traversal outside the base directory", () => {
expect(resolvePathWithinBase(baseDir, "/../../etc/passwd")).toBeNull();
});

test("contains repeated leading slashes within the base directory", () => {
expect(resolvePathWithinBase(baseDir, "//etc/passwd")).toBe(
resolve(baseDir, "etc/passwd"),
);
});

@gemini-code-assistgemini-code-assistBotMar 22, 2026

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medium

To complement the suggested change in safePath.ts, it would be beneficial to add a test case that verifies that valid paths containing .. which resolve within the base directory are handled correctly.

);});test("resolves valid paths with '..' segments that stay within the base directory",()=>{expect(resolvePathWithinBase(baseDir,"/assets/css/../js/app.js"),).toBe(resolve(baseDir,"assets/js/app.js"));});

});
18 changes: 18 additions & 0 deletions backend/src/utils/safePath.ts
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
import { resolve } from "node:path";

export function resolvePathWithinBase(
baseDir: string,
requestPath: string,
): string | null {
const normalizedRequestPath = requestPath.replaceAll("\\", "/");
const pathSegments = normalizedRequestPath
.replace(/^\/+/, "")
.split("/")
.filter(Boolean);

if (pathSegments.includes("..")) {
return null;
}

return resolve(baseDir, ...pathSegments);
}
Comment on lines +1 to +18

@gemini-code-assistgemini-code-assistBotMar 22, 2026

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security-mediummedium

The current implementation is a bit too restrictive as it rejects any path containing .., even if it resolves to a path still within the base directory (e.g., /foo/../bar). A more robust approach is to resolve the path first and then verify that it is still within the intended base directory. This allows for valid relative paths while still preventing directory traversal attacks. I've also added a check for null byte injection as an extra precaution.

import{isAbsolute,relative,resolve}from"node:path";exportfunctionresolvePathWithinBase(baseDir: string,requestPath: string,): string|null{// Prevent null byte injection.if(requestPath.includes("\u0000")){returnnull;}// Resolve the path. This will process '..', '.', etc.// We must treat requestPath as relative to baseDir, so we remove leading slashes.constresolvedPath=resolve(baseDir,requestPath.replace(/^\/+/,""));// Check if the resolved path is a sub-path of baseDir.constrelation=relative(baseDir,resolvedPath);// If `relation` is empty, it's the base directory itself.// If it starts with '..', it has escaped the base directory.// An absolute path as `relation` is also an escape.if(relation.startsWith("..")||isAbsolute(relation)){returnnull;}returnresolvedPath;}

Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
fix(docs): prevent path traversal in /docs static handler by pescn · Pull Request #80 · EM-GeekLab/NexusGate · GitHub
Skip to content
fix(docs): prevent path traversal in /docs static handler#80

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 Open

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fix(docs): prevent path traversal in /docs static handler
#80
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20 changes: 16 additions & 4 deletions
backend/src/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,6 +15,7 @@ async function exists(path: string): Promise<boolean> {
 }
}
import { join } from "node:path";
import { resolvePathWithinBase } from "@/utils/safePath";
import { routes } from "@/api";
import { metricsApi } from "@/api/metrics";
import { loggerPlugin } from "@/plugins/loggerPlugin";
Expand DownExpand Up@@ -91,7 +92,12 @@ async function docsPlugin(dir: string) {
 // Handle TanStack Start's __tsr static server function cache requests
 // These are requested from root path, not /docs/
 .get("/__tsr/*", async ({ path, status }) => {
 const response = await serveStaticFile(join(dir, path));
 const filePath = resolvePathWithinBase(dir, path);
 if (!filePath) {
 return status(404);
 }

 const response = await serveStaticFile(filePath);
 return response || status(404);
 })
 .get("/docs", ({ status }) => {
Expand All@@ -107,7 +113,10 @@ async function docsPlugin(dir: string) {
 return status(404);
 }
 const subPath = path.replace("/docs", "");
 const exactPath = join(dir, subPath);
 const exactPath = resolvePathWithinBase(dir, subPath);
 if (!exactPath) {
 return status(404);
 }

 // Try to serve as static file
 const staticResponse = await serveStaticFile(exactPath);
Expand All@@ -116,8 +125,11 @@ async function docsPlugin(dir: string) {
 }

 // Check if there's a specific HTML file for this path (directory with index.html)
 const specificHtmlPath = join(dir, subPath, "index.html");
 if (await exists(specificHtmlPath)) {
 const specificHtmlPath = resolvePathWithinBase(
 dir,
 join(subPath, "index.html"),
 );
 if (specificHtmlPath && (await exists(specificHtmlPath))) {
 const html = await readFile(specificHtmlPath, "utf-8");
 return new Response(html, {
 headers: { "Content-Type": "text/html" },
Expand Down

27 changes: 27 additions & 0 deletions
backend/src/utils/safePath.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
import { describe, expect, test } from "bun:test";
import { resolve } from "node:path";
import { resolvePathWithinBase } from "./safePath";

describe("resolvePathWithinBase", () => {
 const baseDir = resolve("/tmp/docs-base");

 test("resolves nested relative paths inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/assets/app.js")).toBe(
 resolve(baseDir, "assets/app.js"),
 );
 });

 test("keeps base directory requests inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/")).toBe(baseDir);
 });

 test("rejects traversal outside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/../../etc/passwd")).toBeNull();
 });

 test("contains repeated leading slashes within the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "//etc/passwd")).toBe(
 resolve(baseDir, "etc/passwd"),
 );
 });
@gemini-code-assistgemini-code-assistBotMar 22, 2026

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medium
To complement the suggested change in safePath.ts, it would be beneficial to add a test case that verifies that valid paths containing .. which resolve within the base directory are handled correctly.
);});test("resolves valid paths with '..' segments that stay within the base directory",()=>{expect(resolvePathWithinBase(baseDir,"/assets/css/../js/app.js"),).toBe(resolve(baseDir,"assets/js/app.js"));});
});

18 changes: 18 additions & 0 deletions
backend/src/utils/safePath.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
import { resolve } from "node:path";

export function resolvePathWithinBase(
 baseDir: string,
 requestPath: string,
): string | null {
 const normalizedRequestPath = requestPath.replaceAll("\\", "/");
 const pathSegments = normalizedRequestPath
 .replace(/^\/+/, "")
 .split("/")
 .filter(Boolean);

 if (pathSegments.includes("..")) {
 return null;
 }

 return resolve(baseDir, ...pathSegments);
}

Comment on lines

+1
 to 
+18

@gemini-code-assistgemini-code-assistBotMar 22, 2026

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security-mediummedium
The current implementation is a bit too restrictive as it rejects any path containing .., even if it resolves to a path still within the base directory (e.g., /foo/../bar). A more robust approach is to resolve the path first and then verify that it is still within the intended base directory. This allows for valid relative paths while still preventing directory traversal attacks. I've also added a check for null byte injection as an extra precaution.
import{isAbsolute,relative,resolve}from"node:path";exportfunctionresolvePathWithinBase(baseDir: string,requestPath: string,): string|null{// Prevent null byte injection.if(requestPath.includes("\u0000")){returnnull;}// Resolve the path. This will process '..', '.', etc.// We must treat requestPath as relative to baseDir, so we remove leading slashes.constresolvedPath=resolve(baseDir,requestPath.replace(/^\/+/,""));// Check if the resolved path is a sub-path of baseDir.constrelation=relative(baseDir,resolvedPath);// If `relation` is empty, it's the base directory itself.// If it starts with '..', it has escaped the base directory.// An absolute path as `relation` is also an escape.if(relation.startsWith("..")||isAbsolute(relation)){returnnull;}returnresolvedPath;}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
fix(docs): prevent path traversal in /docs static handler by pescn · Pull Request #80 · EM-GeekLab/NexusGate · GitHub
Skip to content
fix(docs): prevent path traversal in /docs static handler#80

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fix(docs): prevent path traversal in /docs static handler
#80
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20 changes: 16 additions & 4 deletions
backend/src/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,6 +15,7 @@ async function exists(path: string): Promise<boolean> {
 }
}
import { join } from "node:path";
import { resolvePathWithinBase } from "@/utils/safePath";
import { routes } from "@/api";
import { metricsApi } from "@/api/metrics";
import { loggerPlugin } from "@/plugins/loggerPlugin";
Expand DownExpand Up@@ -91,7 +92,12 @@ async function docsPlugin(dir: string) {
 // Handle TanStack Start's __tsr static server function cache requests
 // These are requested from root path, not /docs/
 .get("/__tsr/*", async ({ path, status }) => {
 const response = await serveStaticFile(join(dir, path));
 const filePath = resolvePathWithinBase(dir, path);
 if (!filePath) {
 return status(404);
 }

 const response = await serveStaticFile(filePath);
 return response || status(404);
 })
 .get("/docs", ({ status }) => {
Expand All@@ -107,7 +113,10 @@ async function docsPlugin(dir: string) {
 return status(404);
 }
 const subPath = path.replace("/docs", "");
 const exactPath = join(dir, subPath);
 const exactPath = resolvePathWithinBase(dir, subPath);
 if (!exactPath) {
 return status(404);
 }

 // Try to serve as static file
 const staticResponse = await serveStaticFile(exactPath);
Expand All@@ -116,8 +125,11 @@ async function docsPlugin(dir: string) {
 }

 // Check if there's a specific HTML file for this path (directory with index.html)
 const specificHtmlPath = join(dir, subPath, "index.html");
 if (await exists(specificHtmlPath)) {
 const specificHtmlPath = resolvePathWithinBase(
 dir,
 join(subPath, "index.html"),
 );
 if (specificHtmlPath && (await exists(specificHtmlPath))) {
 const html = await readFile(specificHtmlPath, "utf-8");
 return new Response(html, {
 headers: { "Content-Type": "text/html" },
Expand Down

27 changes: 27 additions & 0 deletions
backend/src/utils/safePath.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
import { describe, expect, test } from "bun:test";
import { resolve } from "node:path";
import { resolvePathWithinBase } from "./safePath";

describe("resolvePathWithinBase", () => {
 const baseDir = resolve("/tmp/docs-base");

 test("resolves nested relative paths inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/assets/app.js")).toBe(
 resolve(baseDir, "assets/app.js"),
 );
 });

 test("keeps base directory requests inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/")).toBe(baseDir);
 });

 test("rejects traversal outside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/../../etc/passwd")).toBeNull();
 });

 test("contains repeated leading slashes within the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "//etc/passwd")).toBe(
 resolve(baseDir, "etc/passwd"),
 );
 });
@gemini-code-assistgemini-code-assistBotMar 22, 2026

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medium
To complement the suggested change in safePath.ts, it would be beneficial to add a test case that verifies that valid paths containing .. which resolve within the base directory are handled correctly.
);});test("resolves valid paths with '..' segments that stay within the base directory",()=>{expect(resolvePathWithinBase(baseDir,"/assets/css/../js/app.js"),).toBe(resolve(baseDir,"assets/js/app.js"));});
});

18 changes: 18 additions & 0 deletions
backend/src/utils/safePath.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
import { resolve } from "node:path";

export function resolvePathWithinBase(
 baseDir: string,
 requestPath: string,
): string | null {
 const normalizedRequestPath = requestPath.replaceAll("\\", "/");
 const pathSegments = normalizedRequestPath
 .replace(/^\/+/, "")
 .split("/")
 .filter(Boolean);

 if (pathSegments.includes("..")) {
 return null;
 }

 return resolve(baseDir, ...pathSegments);
}

Comment on lines

+1
 to 
+18

@gemini-code-assistgemini-code-assistBotMar 22, 2026

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security-mediummedium
The current implementation is a bit too restrictive as it rejects any path containing .., even if it resolves to a path still within the base directory (e.g., /foo/../bar). A more robust approach is to resolve the path first and then verify that it is still within the intended base directory. This allows for valid relative paths while still preventing directory traversal attacks. I've also added a check for null byte injection as an extra precaution.
import{isAbsolute,relative,resolve}from"node:path";exportfunctionresolvePathWithinBase(baseDir: string,requestPath: string,): string|null{// Prevent null byte injection.if(requestPath.includes("\u0000")){returnnull;}// Resolve the path. This will process '..', '.', etc.// We must treat requestPath as relative to baseDir, so we remove leading slashes.constresolvedPath=resolve(baseDir,requestPath.replace(/^\/+/,""));// Check if the resolved path is a sub-path of baseDir.constrelation=relative(baseDir,resolvedPath);// If `relation` is empty, it's the base directory itself.// If it starts with '..', it has escaped the base directory.// An absolute path as `relation` is also an escape.if(relation.startsWith("..")||isAbsolute(relation)){returnnull;}returnresolvedPath;}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
fix(docs): prevent path traversal in /docs static handler by pescn · Pull Request #80 · EM-GeekLab/NexusGate · GitHub
Skip to content
fix(docs): prevent path traversal in /docs static handler#80

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fix(docs): prevent path traversal in /docs static handler
#80
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20 changes: 16 additions & 4 deletions
backend/src/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,6 +15,7 @@ async function exists(path: string): Promise<boolean> {
 }
}
import { join } from "node:path";
import { resolvePathWithinBase } from "@/utils/safePath";
import { routes } from "@/api";
import { metricsApi } from "@/api/metrics";
import { loggerPlugin } from "@/plugins/loggerPlugin";
Expand DownExpand Up@@ -91,7 +92,12 @@ async function docsPlugin(dir: string) {
 // Handle TanStack Start's __tsr static server function cache requests
 // These are requested from root path, not /docs/
 .get("/__tsr/*", async ({ path, status }) => {
 const response = await serveStaticFile(join(dir, path));
 const filePath = resolvePathWithinBase(dir, path);
 if (!filePath) {
 return status(404);
 }

 const response = await serveStaticFile(filePath);
 return response || status(404);
 })
 .get("/docs", ({ status }) => {
Expand All@@ -107,7 +113,10 @@ async function docsPlugin(dir: string) {
 return status(404);
 }
 const subPath = path.replace("/docs", "");
 const exactPath = join(dir, subPath);
 const exactPath = resolvePathWithinBase(dir, subPath);
 if (!exactPath) {
 return status(404);
 }

 // Try to serve as static file
 const staticResponse = await serveStaticFile(exactPath);
Expand All@@ -116,8 +125,11 @@ async function docsPlugin(dir: string) {
 }

 // Check if there's a specific HTML file for this path (directory with index.html)
 const specificHtmlPath = join(dir, subPath, "index.html");
 if (await exists(specificHtmlPath)) {
 const specificHtmlPath = resolvePathWithinBase(
 dir,
 join(subPath, "index.html"),
 );
 if (specificHtmlPath && (await exists(specificHtmlPath))) {
 const html = await readFile(specificHtmlPath, "utf-8");
 return new Response(html, {
 headers: { "Content-Type": "text/html" },
Expand Down

27 changes: 27 additions & 0 deletions
backend/src/utils/safePath.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
import { describe, expect, test } from "bun:test";
import { resolve } from "node:path";
import { resolvePathWithinBase } from "./safePath";

describe("resolvePathWithinBase", () => {
 const baseDir = resolve("/tmp/docs-base");

 test("resolves nested relative paths inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/assets/app.js")).toBe(
 resolve(baseDir, "assets/app.js"),
 );
 });

 test("keeps base directory requests inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/")).toBe(baseDir);
 });

 test("rejects traversal outside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/../../etc/passwd")).toBeNull();
 });

 test("contains repeated leading slashes within the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "//etc/passwd")).toBe(
 resolve(baseDir, "etc/passwd"),
 );
 });
@gemini-code-assistgemini-code-assistBotMar 22, 2026

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medium
To complement the suggested change in safePath.ts, it would be beneficial to add a test case that verifies that valid paths containing .. which resolve within the base directory are handled correctly.
);});test("resolves valid paths with '..' segments that stay within the base directory",()=>{expect(resolvePathWithinBase(baseDir,"/assets/css/../js/app.js"),).toBe(resolve(baseDir,"assets/js/app.js"));});
});

18 changes: 18 additions & 0 deletions
backend/src/utils/safePath.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
import { resolve } from "node:path";

export function resolvePathWithinBase(
 baseDir: string,
 requestPath: string,
): string | null {
 const normalizedRequestPath = requestPath.replaceAll("\\", "/");
 const pathSegments = normalizedRequestPath
 .replace(/^\/+/, "")
 .split("/")
 .filter(Boolean);

 if (pathSegments.includes("..")) {
 return null;
 }

 return resolve(baseDir, ...pathSegments);
}

Comment on lines

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 to 
+18

@gemini-code-assistgemini-code-assistBotMar 22, 2026

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security-mediummedium
The current implementation is a bit too restrictive as it rejects any path containing .., even if it resolves to a path still within the base directory (e.g., /foo/../bar). A more robust approach is to resolve the path first and then verify that it is still within the intended base directory. This allows for valid relative paths while still preventing directory traversal attacks. I've also added a check for null byte injection as an extra precaution.
import{isAbsolute,relative,resolve}from"node:path";exportfunctionresolvePathWithinBase(baseDir: string,requestPath: string,): string|null{// Prevent null byte injection.if(requestPath.includes("\u0000")){returnnull;}// Resolve the path. This will process '..', '.', etc.// We must treat requestPath as relative to baseDir, so we remove leading slashes.constresolvedPath=resolve(baseDir,requestPath.replace(/^\/+/,""));// Check if the resolved path is a sub-path of baseDir.constrelation=relative(baseDir,resolvedPath);// If `relation` is empty, it's the base directory itself.// If it starts with '..', it has escaped the base directory.// An absolute path as `relation` is also an escape.if(relation.startsWith("..")||isAbsolute(relation)){returnnull;}returnresolvedPath;}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
fix(docs): prevent path traversal in /docs static handler by pescn · Pull Request #80 · EM-GeekLab/NexusGate · GitHub
Skip to content
fix(docs): prevent path traversal in /docs static handler#80

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fix(docs): prevent path traversal in /docs static handler
#80
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20 changes: 16 additions & 4 deletions
backend/src/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,6 +15,7 @@ async function exists(path: string): Promise<boolean> {
 }
}
import { join } from "node:path";
import { resolvePathWithinBase } from "@/utils/safePath";
import { routes } from "@/api";
import { metricsApi } from "@/api/metrics";
import { loggerPlugin } from "@/plugins/loggerPlugin";
Expand DownExpand Up@@ -91,7 +92,12 @@ async function docsPlugin(dir: string) {
 // Handle TanStack Start's __tsr static server function cache requests
 // These are requested from root path, not /docs/
 .get("/__tsr/*", async ({ path, status }) => {
 const response = await serveStaticFile(join(dir, path));
 const filePath = resolvePathWithinBase(dir, path);
 if (!filePath) {
 return status(404);
 }

 const response = await serveStaticFile(filePath);
 return response || status(404);
 })
 .get("/docs", ({ status }) => {
Expand All@@ -107,7 +113,10 @@ async function docsPlugin(dir: string) {
 return status(404);
 }
 const subPath = path.replace("/docs", "");
 const exactPath = join(dir, subPath);
 const exactPath = resolvePathWithinBase(dir, subPath);
 if (!exactPath) {
 return status(404);
 }

 // Try to serve as static file
 const staticResponse = await serveStaticFile(exactPath);
Expand All@@ -116,8 +125,11 @@ async function docsPlugin(dir: string) {
 }

 // Check if there's a specific HTML file for this path (directory with index.html)
 const specificHtmlPath = join(dir, subPath, "index.html");
 if (await exists(specificHtmlPath)) {
 const specificHtmlPath = resolvePathWithinBase(
 dir,
 join(subPath, "index.html"),
 );
 if (specificHtmlPath && (await exists(specificHtmlPath))) {
 const html = await readFile(specificHtmlPath, "utf-8");
 return new Response(html, {
 headers: { "Content-Type": "text/html" },
Expand Down

27 changes: 27 additions & 0 deletions
backend/src/utils/safePath.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
import { describe, expect, test } from "bun:test";
import { resolve } from "node:path";
import { resolvePathWithinBase } from "./safePath";

describe("resolvePathWithinBase", () => {
 const baseDir = resolve("/tmp/docs-base");

 test("resolves nested relative paths inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/assets/app.js")).toBe(
 resolve(baseDir, "assets/app.js"),
 );
 });

 test("keeps base directory requests inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/")).toBe(baseDir);
 });

 test("rejects traversal outside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/../../etc/passwd")).toBeNull();
 });

 test("contains repeated leading slashes within the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "//etc/passwd")).toBe(
 resolve(baseDir, "etc/passwd"),
 );
 });
@gemini-code-assistgemini-code-assistBotMar 22, 2026

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medium
To complement the suggested change in safePath.ts, it would be beneficial to add a test case that verifies that valid paths containing .. which resolve within the base directory are handled correctly.
);});test("resolves valid paths with '..' segments that stay within the base directory",()=>{expect(resolvePathWithinBase(baseDir,"/assets/css/../js/app.js"),).toBe(resolve(baseDir,"assets/js/app.js"));});
});

18 changes: 18 additions & 0 deletions
backend/src/utils/safePath.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
import { resolve } from "node:path";

export function resolvePathWithinBase(
 baseDir: string,
 requestPath: string,
): string | null {
 const normalizedRequestPath = requestPath.replaceAll("\\", "/");
 const pathSegments = normalizedRequestPath
 .replace(/^\/+/, "")
 .split("/")
 .filter(Boolean);

 if (pathSegments.includes("..")) {
 return null;
 }

 return resolve(baseDir, ...pathSegments);
}

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 to 
+18

@gemini-code-assistgemini-code-assistBotMar 22, 2026

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security-mediummedium
The current implementation is a bit too restrictive as it rejects any path containing .., even if it resolves to a path still within the base directory (e.g., /foo/../bar). A more robust approach is to resolve the path first and then verify that it is still within the intended base directory. This allows for valid relative paths while still preventing directory traversal attacks. I've also added a check for null byte injection as an extra precaution.
import{isAbsolute,relative,resolve}from"node:path";exportfunctionresolvePathWithinBase(baseDir: string,requestPath: string,): string|null{// Prevent null byte injection.if(requestPath.includes("\u0000")){returnnull;}// Resolve the path. This will process '..', '.', etc.// We must treat requestPath as relative to baseDir, so we remove leading slashes.constresolvedPath=resolve(baseDir,requestPath.replace(/^\/+/,""));// Check if the resolved path is a sub-path of baseDir.constrelation=relative(baseDir,resolvedPath);// If `relation` is empty, it's the base directory itself.// If it starts with '..', it has escaped the base directory.// An absolute path as `relation` is also an escape.if(relation.startsWith("..")||isAbsolute(relation)){returnnull;}returnresolvedPath;}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
fix(docs): prevent path traversal in /docs static handler by pescn · Pull Request #80 · EM-GeekLab/NexusGate · GitHub
Skip to content
fix(docs): prevent path traversal in /docs static handler#80

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fix(docs): prevent path traversal in /docs static handler
#80
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20 changes: 16 additions & 4 deletions
backend/src/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,6 +15,7 @@ async function exists(path: string): Promise<boolean> {
 }
}
import { join } from "node:path";
import { resolvePathWithinBase } from "@/utils/safePath";
import { routes } from "@/api";
import { metricsApi } from "@/api/metrics";
import { loggerPlugin } from "@/plugins/loggerPlugin";
Expand DownExpand Up@@ -91,7 +92,12 @@ async function docsPlugin(dir: string) {
 // Handle TanStack Start's __tsr static server function cache requests
 // These are requested from root path, not /docs/
 .get("/__tsr/*", async ({ path, status }) => {
 const response = await serveStaticFile(join(dir, path));
 const filePath = resolvePathWithinBase(dir, path);
 if (!filePath) {
 return status(404);
 }

 const response = await serveStaticFile(filePath);
 return response || status(404);
 })
 .get("/docs", ({ status }) => {
Expand All@@ -107,7 +113,10 @@ async function docsPlugin(dir: string) {
 return status(404);
 }
 const subPath = path.replace("/docs", "");
 const exactPath = join(dir, subPath);
 const exactPath = resolvePathWithinBase(dir, subPath);
 if (!exactPath) {
 return status(404);
 }

 // Try to serve as static file
 const staticResponse = await serveStaticFile(exactPath);
Expand All@@ -116,8 +125,11 @@ async function docsPlugin(dir: string) {
 }

 // Check if there's a specific HTML file for this path (directory with index.html)
 const specificHtmlPath = join(dir, subPath, "index.html");
 if (await exists(specificHtmlPath)) {
 const specificHtmlPath = resolvePathWithinBase(
 dir,
 join(subPath, "index.html"),
 );
 if (specificHtmlPath && (await exists(specificHtmlPath))) {
 const html = await readFile(specificHtmlPath, "utf-8");
 return new Response(html, {
 headers: { "Content-Type": "text/html" },
Expand Down

27 changes: 27 additions & 0 deletions
backend/src/utils/safePath.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
import { describe, expect, test } from "bun:test";
import { resolve } from "node:path";
import { resolvePathWithinBase } from "./safePath";

describe("resolvePathWithinBase", () => {
 const baseDir = resolve("/tmp/docs-base");

 test("resolves nested relative paths inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/assets/app.js")).toBe(
 resolve(baseDir, "assets/app.js"),
 );
 });

 test("keeps base directory requests inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/")).toBe(baseDir);
 });

 test("rejects traversal outside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/../../etc/passwd")).toBeNull();
 });

 test("contains repeated leading slashes within the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "//etc/passwd")).toBe(
 resolve(baseDir, "etc/passwd"),
 );
 });
@gemini-code-assistgemini-code-assistBotMar 22, 2026

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medium
To complement the suggested change in safePath.ts, it would be beneficial to add a test case that verifies that valid paths containing .. which resolve within the base directory are handled correctly.
);});test("resolves valid paths with '..' segments that stay within the base directory",()=>{expect(resolvePathWithinBase(baseDir,"/assets/css/../js/app.js"),).toBe(resolve(baseDir,"assets/js/app.js"));});
});

18 changes: 18 additions & 0 deletions
backend/src/utils/safePath.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
import { resolve } from "node:path";

export function resolvePathWithinBase(
 baseDir: string,
 requestPath: string,
): string | null {
 const normalizedRequestPath = requestPath.replaceAll("\\", "/");
 const pathSegments = normalizedRequestPath
 .replace(/^\/+/, "")
 .split("/")
 .filter(Boolean);

 if (pathSegments.includes("..")) {
 return null;
 }

 return resolve(baseDir, ...pathSegments);
}

Comment on lines

+1
 to 
+18

@gemini-code-assistgemini-code-assistBotMar 22, 2026

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security-mediummedium
The current implementation is a bit too restrictive as it rejects any path containing .., even if it resolves to a path still within the base directory (e.g., /foo/../bar). A more robust approach is to resolve the path first and then verify that it is still within the intended base directory. This allows for valid relative paths while still preventing directory traversal attacks. I've also added a check for null byte injection as an extra precaution.
import{isAbsolute,relative,resolve}from"node:path";exportfunctionresolvePathWithinBase(baseDir: string,requestPath: string,): string|null{// Prevent null byte injection.if(requestPath.includes("\u0000")){returnnull;}// Resolve the path. This will process '..', '.', etc.// We must treat requestPath as relative to baseDir, so we remove leading slashes.constresolvedPath=resolve(baseDir,requestPath.replace(/^\/+/,""));// Check if the resolved path is a sub-path of baseDir.constrelation=relative(baseDir,resolvedPath);// If `relation` is empty, it's the base directory itself.// If it starts with '..', it has escaped the base directory.// An absolute path as `relation` is also an escape.if(relation.startsWith("..")||isAbsolute(relation)){returnnull;}returnresolvedPath;}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
fix(docs): prevent path traversal in /docs static handler by pescn · Pull Request #80 · EM-GeekLab/NexusGate · GitHub
Skip to content
fix(docs): prevent path traversal in /docs static handler#80

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 Open

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fix(docs): prevent path traversal in /docs static handler
#80
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20 changes: 16 additions & 4 deletions
backend/src/index.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,6 +15,7 @@ async function exists(path: string): Promise<boolean> {
 }
}
import { join } from "node:path";
import { resolvePathWithinBase } from "@/utils/safePath";
import { routes } from "@/api";
import { metricsApi } from "@/api/metrics";
import { loggerPlugin } from "@/plugins/loggerPlugin";
Expand DownExpand Up@@ -91,7 +92,12 @@ async function docsPlugin(dir: string) {
 // Handle TanStack Start's __tsr static server function cache requests
 // These are requested from root path, not /docs/
 .get("/__tsr/*", async ({ path, status }) => {
 const response = await serveStaticFile(join(dir, path));
 const filePath = resolvePathWithinBase(dir, path);
 if (!filePath) {
 return status(404);
 }

 const response = await serveStaticFile(filePath);
 return response || status(404);
 })
 .get("/docs", ({ status }) => {
Expand All@@ -107,7 +113,10 @@ async function docsPlugin(dir: string) {
 return status(404);
 }
 const subPath = path.replace("/docs", "");
 const exactPath = join(dir, subPath);
 const exactPath = resolvePathWithinBase(dir, subPath);
 if (!exactPath) {
 return status(404);
 }

 // Try to serve as static file
 const staticResponse = await serveStaticFile(exactPath);
Expand All@@ -116,8 +125,11 @@ async function docsPlugin(dir: string) {
 }

 // Check if there's a specific HTML file for this path (directory with index.html)
 const specificHtmlPath = join(dir, subPath, "index.html");
 if (await exists(specificHtmlPath)) {
 const specificHtmlPath = resolvePathWithinBase(
 dir,
 join(subPath, "index.html"),
 );
 if (specificHtmlPath && (await exists(specificHtmlPath))) {
 const html = await readFile(specificHtmlPath, "utf-8");
 return new Response(html, {
 headers: { "Content-Type": "text/html" },
Expand Down

27 changes: 27 additions & 0 deletions
backend/src/utils/safePath.test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
import { describe, expect, test } from "bun:test";
import { resolve } from "node:path";
import { resolvePathWithinBase } from "./safePath";

describe("resolvePathWithinBase", () => {
 const baseDir = resolve("/tmp/docs-base");

 test("resolves nested relative paths inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/assets/app.js")).toBe(
 resolve(baseDir, "assets/app.js"),
 );
 });

 test("keeps base directory requests inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/")).toBe(baseDir);
 });

 test("rejects traversal outside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/../../etc/passwd")).toBeNull();
 });

 test("contains repeated leading slashes within the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "//etc/passwd")).toBe(
 resolve(baseDir, "etc/passwd"),
 );
 });
@gemini-code-assistgemini-code-assistBotMar 22, 2026

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medium
To complement the suggested change in safePath.ts, it would be beneficial to add a test case that verifies that valid paths containing .. which resolve within the base directory are handled correctly.
);});test("resolves valid paths with '..' segments that stay within the base directory",()=>{expect(resolvePathWithinBase(baseDir,"/assets/css/../js/app.js"),).toBe(resolve(baseDir,"assets/js/app.js"));});
});

18 changes: 18 additions & 0 deletions
backend/src/utils/safePath.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
import { resolve } from "node:path";

export function resolvePathWithinBase(
 baseDir: string,
 requestPath: string,
): string | null {
 const normalizedRequestPath = requestPath.replaceAll("\\", "/");
 const pathSegments = normalizedRequestPath
 .replace(/^\/+/, "")
 .split("/")
 .filter(Boolean);

 if (pathSegments.includes("..")) {
 return null;
 }

 return resolve(baseDir, ...pathSegments);
}

Comment on lines

+1
 to 
+18

@gemini-code-assistgemini-code-assistBotMar 22, 2026

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security-mediummedium
The current implementation is a bit too restrictive as it rejects any path containing .., even if it resolves to a path still within the base directory (e.g., /foo/../bar). A more robust approach is to resolve the path first and then verify that it is still within the intended base directory. This allows for valid relative paths while still preventing directory traversal attacks. I've also added a check for null byte injection as an extra precaution.
import{isAbsolute,relative,resolve}from"node:path";exportfunctionresolvePathWithinBase(baseDir: string,requestPath: string,): string|null{// Prevent null byte injection.if(requestPath.includes("\u0000")){returnnull;}// Resolve the path. This will process '..', '.', etc.// We must treat requestPath as relative to baseDir, so we remove leading slashes.constresolvedPath=resolve(baseDir,requestPath.replace(/^\/+/,""));// Check if the resolved path is a sub-path of baseDir.constrelation=relative(baseDir,resolvedPath);// If `relation` is empty, it's the base directory itself.// If it starts with '..', it has escaped the base directory.// An absolute path as `relation` is also an escape.if(relation.startsWith("..")||isAbsolute(relation)){returnnull;}returnresolvedPath;}
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, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
fix(docs): prevent path traversal in /docs static handler by pescn · Pull Request #80 · EM-GeekLab/NexusGate · GitHub
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fix(docs): prevent path traversal in /docs static handler#80

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fix(docs): prevent path traversal in /docs static handler
#80
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20 changes: 16 additions & 4 deletions
backend/src/index.ts

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,6 +15,7 @@ async function exists(path: string): Promise<boolean> {
 }
}
import { join } from "node:path";
import { resolvePathWithinBase } from "@/utils/safePath";
import { routes } from "@/api";
import { metricsApi } from "@/api/metrics";
import { loggerPlugin } from "@/plugins/loggerPlugin";
Expand DownExpand Up@@ -91,7 +92,12 @@ async function docsPlugin(dir: string) {
 // Handle TanStack Start's __tsr static server function cache requests
 // These are requested from root path, not /docs/
 .get("/__tsr/*", async ({ path, status }) => {
 const response = await serveStaticFile(join(dir, path));
 const filePath = resolvePathWithinBase(dir, path);
 if (!filePath) {
 return status(404);
 }

 const response = await serveStaticFile(filePath);
 return response || status(404);
 })
 .get("/docs", ({ status }) => {
Expand All@@ -107,7 +113,10 @@ async function docsPlugin(dir: string) {
 return status(404);
 }
 const subPath = path.replace("/docs", "");
 const exactPath = join(dir, subPath);
 const exactPath = resolvePathWithinBase(dir, subPath);
 if (!exactPath) {
 return status(404);
 }

 // Try to serve as static file
 const staticResponse = await serveStaticFile(exactPath);
Expand All@@ -116,8 +125,11 @@ async function docsPlugin(dir: string) {
 }

 // Check if there's a specific HTML file for this path (directory with index.html)
 const specificHtmlPath = join(dir, subPath, "index.html");
 if (await exists(specificHtmlPath)) {
 const specificHtmlPath = resolvePathWithinBase(
 dir,
 join(subPath, "index.html"),
 );
 if (specificHtmlPath && (await exists(specificHtmlPath))) {
 const html = await readFile(specificHtmlPath, "utf-8");
 return new Response(html, {
 headers: { "Content-Type": "text/html" },
Expand Down

27 changes: 27 additions & 0 deletions
backend/src/utils/safePath.test.ts

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
import { describe, expect, test } from "bun:test";
import { resolve } from "node:path";
import { resolvePathWithinBase } from "./safePath";

describe("resolvePathWithinBase", () => {
 const baseDir = resolve("/tmp/docs-base");

 test("resolves nested relative paths inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/assets/app.js")).toBe(
 resolve(baseDir, "assets/app.js"),
 );
 });

 test("keeps base directory requests inside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/")).toBe(baseDir);
 });

 test("rejects traversal outside the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "/../../etc/passwd")).toBeNull();
 });

 test("contains repeated leading slashes within the base directory", () => {
 expect(resolvePathWithinBase(baseDir, "//etc/passwd")).toBe(
 resolve(baseDir, "etc/passwd"),
 );
 });
@gemini-code-assistgemini-code-assistBotMar 22, 2026

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medium
To complement the suggested change in safePath.ts, it would be beneficial to add a test case that verifies that valid paths containing .. which resolve within the base directory are handled correctly.
);});test("resolves valid paths with '..' segments that stay within the base directory",()=>{expect(resolvePathWithinBase(baseDir,"/assets/css/../js/app.js"),).toBe(resolve(baseDir,"assets/js/app.js"));});
});

18 changes: 18 additions & 0 deletions
backend/src/utils/safePath.ts

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Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
import { resolve } from "node:path";

export function resolvePathWithinBase(
 baseDir: string,
 requestPath: string,
): string | null {
 const normalizedRequestPath = requestPath.replaceAll("\\", "/");
 const pathSegments = normalizedRequestPath
 .replace(/^\/+/, "")
 .split("/")
 .filter(Boolean);

 if (pathSegments.includes("..")) {
 return null;
 }

 return resolve(baseDir, ...pathSegments);
}

Comment on lines

+1
 to 
+18

@gemini-code-assistgemini-code-assistBotMar 22, 2026

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security-mediummedium
The current implementation is a bit too restrictive as it rejects any path containing .., even if it resolves to a path still within the base directory (e.g., /foo/../bar). A more robust approach is to resolve the path first and then verify that it is still within the intended base directory. This allows for valid relative paths while still preventing directory traversal attacks. I've also added a check for null byte injection as an extra precaution.
import{isAbsolute,relative,resolve}from"node:path";exportfunctionresolvePathWithinBase(baseDir: string,requestPath: string,): string|null{// Prevent null byte injection.if(requestPath.includes("\u0000")){returnnull;}// Resolve the path. This will process '..', '.', etc.// We must treat requestPath as relative to baseDir, so we remove leading slashes.constresolvedPath=resolve(baseDir,requestPath.replace(/^\/+/,""));// Check if the resolved path is a sub-path of baseDir.constrelation=relative(baseDir,resolvedPath);// If `relation` is empty, it's the base directory itself.// If it starts with '..', it has escaped the base directory.// An absolute path as `relation` is also an escape.if(relation.startsWith("..")||isAbsolute(relation)){returnnull;}returnresolvedPath;}
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