Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Decrypting CloudFormation secrets using a Lamba function
'use strict';
const https = require('https');
const url = require('url');
function sendResponse(event, callback, logStreamName, responseStatus, responseData) {
const responseBody = JSON.stringify({
Status: responseStatus,
Reason: `See the details in CloudWatch Log Stream: ${logStreamName}`,
PhysicalResourceId: logStreamName,
StackId: event.StackId,
RequestId: event.RequestId,
LogicalResourceId: event.LogicalResourceId,
Data: responseData,
});
const parsedUrl = url.parse(event.ResponseURL);
const options = {
hostname: parsedUrl.hostname,
port: 443,
path: parsedUrl.path,
method: 'PUT',
headers: {
'Content-Type': '',
'Content-Length': responseBody.length,
},
};
const req = https.request(options, (res) => {
console.log('STATUS:', res.statusCode);
console.log('HEADERS:', JSON.stringify(res.headers));
callback(null, 'Successfully sent stack response!');
});
req.on('error', (err) => {
console.log('sendResponse Error:\n', err);
callback(err);
});
req.write(responseBody);
req.end();
}
exports.handler = (event, context, callback) => {
console.log('Received event:', JSON.stringify(event, null, 2));
if (event.RequestType === 'Delete') {
sendResponse(event, callback, context.logStreamName, 'SUCCESS');
return;
}
let responseStatus = 'FAILED';
let responseData = {};
var AWS = require('aws-sdk');
var KMS = new AWS.KMS({apiVersion:'2014-11-01', region:event.ResourceProperties.Region});
var params = {
CiphertextBlob: Buffer(event.ResourceProperties.CiphertextBlob, 'base64'),
EncryptionContext: event.ResourceProperties.EncryptionContext
};
KMS.decrypt(params, function(err,data){
if(err){
responseData = { Error: 'Unable to decrypt blob: '+err};
console.log(`${responseData.Error}:\n`, err);
} else {
responseStatus = 'SUCCESS';
responseData = {Plaintext: data.Plaintext.toString()};
}
sendResponse(event, callback, context.logStreamName, responseStatus, responseData);
}
);
};
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.