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Fix potential OS command injection in jekyll-hook.js #43

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Fix potential OS command injection in jekyll-hook.js #43

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979c3c1
Implement security checks for webhook data
DongZifan Apr 23, 2026
38cc830
Update jekyll-hook.js
DongZifan May 15, 2026
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34 changes: 28 additions & 6 deletions jekyll-hook.js
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Original file line number Diff line number Diff line change
Expand Up @@ -13,17 +13,32 @@ var crypto = require('crypto');

app.use(express.bodyParser({
verify: function(req,res,buffer){
if(!req.headers['x-hub-signature']){
return;
if (!config.secret || config.secret === "") {
console.warn("Webhook secret is not configured.");
var err = new Error("Webhook secret is required");
err.status = 500;
throw err;
}

if(!config.secret || config.secret==""){
console.log("Recieved a X-Hub-Signature header, but cannot validate as no secret is configured");
return;
if (!req.headers['x-hub-signature']) {
console.warn("Missing X-Hub-Signature header.");
var err = new Error("Missing signature");
err.status = 403;
throw err;
}

var signature = req.headers['x-hub-signature'];
var parts = signature.split('=');

if (parts.length !== 2 || parts[0] !== 'sha1') {
console.warn("Invalid X-Hub-Signature format.");
var err = new Error("Invalid signature format");
err.status = 403;
throw err;
}

var hmac = crypto.createHmac('sha1', config.secret);
var recieved_sig = req.headers['x-hub-signature'].split('=')[1];
var recieved_sig = parts[1];
var computed_sig = hmac.update(buffer).digest('hex');

if(recieved_sig != computed_sig){
Expand Down Expand Up @@ -52,6 +67,13 @@ app.post('/hooks/jekyll/*', function(req, res) {
data.branch = data.ref.replace('refs/heads/', '');
data.owner = data.repository.owner.name;

var safePattern = /^[a-zA-Z0-9._-]+$/;
if (!safePattern.test(data.repo) || !safePattern.test(data.branch) || !safePattern.test(data.owner)) {
console.log('Security Error: Invalid characters detected in webhook data.');
if (typeof cb === 'function') cb();
return;
}

// End early if not permitted account
if (config.accounts.indexOf(data.owner) === -1) {
console.log(data.owner + ' is not an authorized account.');
Expand Down