Thursday, October 30, 2014

Node.js "Error: too many parameters at queryparse"

If you've been using Express' body-parser and attempting to process large data submissions (aka forms with more than 1000 elements or 1000 sub-elements, you may have run into the following error:

Error: too many parameters
    at queryparse (/project/node_modules/body-parser/lib/types/urlencoded.js:120:17)
    at parse (/project/node_modules/body-parser/lib/types/urlencoded.js:64:9)

This is due to the fact the urlencode defaults to 1000 parameters by default. If you have a large form or just an abnormally large JSON submission, you'll need to increase this limit by doing the following:

var bodyParser = require('body-parser');

app.use(bodyParser.urlencoded({
        extended: false,
    parameterLimit: 10000,
    limit: 1024 * 1024 * 10
}));
app.use(bodyParser.json({
        extended: false,
    parameterLimit: 10000,
    limit: 1024 * 1024 * 10
}));


This will allow you to provide up to 10,000 parameters (increase as needed) and 10 MB of data (also adjustable).

Tuesday, October 14, 2014

How to Disable SSLv3 on AWS Elastic Load Balancers

In a blog post today, Google announced that a vulnerability in SSLv3 had been found that could allow attackers to intercept data that had previously been assumed to be secured. Luckily, a very small portion of the web (IE6 users on Windows XP) still use SSLv3, so it can safely, for the most part, be disabled to mitigate the risk from this issue.

http://googleonlinesecurity.blogspot.com/2014/10/this-poodle-bites-exploiting-ssl-30.html

UPDATE 10/15: As Andrew and Julio point out in the comments below, AWS has since updated their default cipher security policies. Replace steps 5 and 6.

To modify the ciphers on AWS ELBs, follow the following steps:

1) Log into the AWS console and click on "Load Balancers."
2) Find the load balancer that handles your site's traffic (you shouldn't need to worry about internal VPC LBs, etc.)
3) Click the "Listeners" tab
4) Find the HTTPS/443 listener and click "Edit" under the cipher column
5) Change the option to "Custom"
6) Uncheck the SSLv3 option
5) Change the policy to "ELBSecurityPolicy-2014-10" which disables SSLv3 for you.
6) Save.

This should be sufficient to mitigate this risk with the information that is currently known.

Redirect HTTP to HTTPS Behind AWS Elastic Load Balancer - Node.js and Apache

Apache

When you enable HTTPS for your website, you should enforce that HTTPS is being used by automatically redirecting users who access your site over HTTP to the HTTPS version. When using Apache, this is done via a host redirect entry with mod_rewrite:

<VirtualHost *:80>

# Beginning declarations here

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^.*$ https://%{SERVER_NAME}%{REQUEST_URI}

# Rest of entry here...
</VirtualHost>

Apache Behind an ELB

However, in the Amazon Web Services world, most applications utilize the load balancer as an SSL-termination point. This means that the traffic is decrypted at the load balancer and all traffic being sent to the final destination instances is actually sent over HTTP (from a security standpoint, this is generally an accepted practice as the load balancer and instance are in the same network, and thus secure from eavesdropping). If you used the rule above, your users would wind up in an endless redirect loop.

To fix this, the "RewriteCond" needs to be changed to:

RewriteCond %{HTTP:X-Forwarded-Proto} !https

This rule will check to see which protocol the user was using before he or she hit the load balancer - which is what HTTPS redirection should use.

Node.js

When using Node.js, the same thing can be accomplished by inserting some middleware that listens for all traffic and redirects the non-HTTPS requests to their HTTPS equivalents.

var myApp = express () ,
myServer = http.createServer(myApp);

myApp.use(function redirectHTTP(req, res, next) {
  if (!req.secure) {
    return res.redirect('https://' + req.headers.host + req.url);
  }
  next();
});

Node.js Behind an ELB

Just as in our first Apache example, this works great until it is placed behind a load balancer. If you're using a load balancer, you need to make some modifications. Instead of "req.secure", do the following:

if (req.headers['x-forwarded-proto'] && req.headers['x-forwarded-proto'].toLowerCase() === 'http') {
return res.redirect('https://' + req.headers.host + req.url);
}

Using these techniques, you should be able to enforce the new HTTPS version of your website. Remember - if you serve both an HTTPS and an HTTP version of your site, the HTTPS is rendered pointless unless you also redirect the HTTP requests.

Sunday, September 28, 2014

Bringing Mint's Interface into the 21st Century

If you use the online financial planning app, Mint, you've probably wondered what decade it was designed in. Just browsing through the site presents a clutter of different styles, an incredible use of box-shadow, and more border-radius than should be permissible by law. It's time for an upgrade (Intuit, if you're reading this, please hire some designers!).

Now I am by no means a graphic designer. In fact, I'd argue that my understanding of colors, patterns, and other design principles is on par with most grade schoolers. However, in about three hours of work on a lazy Sunday afternoon, I was able to turn this:


Into this:



As you can see, not a ton has changed; my goal was not to completely design a new site. However, as I'll show in the next screenshots, I've tried to unify the interface a bit, get rid of the overzealous use of shadows, gradients, and rounded borders, as well as add a bit of white space to spread things out a bit. I also tried to flatten some of the progress bars to get rid of the outdated "Web 2.0" gloss effect.

For the transactions page, I've simply added white space to make things seem less cramped (pardon the gray box, I had to box out some of my own personal info):


Within the budgets page, I've gotten rid of all sorts of rounded glossy boxes and replaced them with whitespace and flat progress bars.


Not much has changed in the "Trends" page, but I did get rid of a lot of the cramped feeling and spread the content out a bit.


Finally, the "Investments" page was given more whitespace as well and a wider width for content:


Here is a list of other little changes I've made:


  • Increased the overall width to 1200px from the original 900. This gives us more room to work and added whitespace.
  • Changed all the popups to have sharp edges rather than rounded corners
  • Replaced the shadows with clean lines
  • Made all the menus square with straight hover edges rather than rounded corners
  • All the progress bars are flat now
  • Removed the bulky hover effects on the budgets page
  • Removed ads on the homepage and investments page
  • Removed the annoying Norton Certified seal in the footer
  • Widened the transactions and their details
  • A bunch of other small touches
I did not:
  • Get rid of the "Ways to Save" page. This is how Mint makes money and I don't want to destroy their revenue stream.
  • Modify the "Goals" page. It is so poorly designed right now with background images and borders and popups I wasn't brave enough to touch it.
  • Change the chart or graph styles for trends
Now, for a disclaimer: I do not guarantee that this will work for everyone's account. I tried to test it as much as possible, but there are a lot of hidden pieces of functionality within Mint that I may have missed. Finally, this code is all written out below. It's entirely CSS, so you can decide which parts you want to use. This code will not steal your account info or do anything else malicious.

I also don't make any guarantees about supporting this in the future. Mint could change their site tomorrow and break all of this. Fortunately, it's very easy to undo (just erase the user styles).

So how can you get this?


It's all CSS! I use an extension called "StyleBot" for Chrome (download link), but Firefox has similar extensions as well. Simply copy and paste the following styles into the extension by opening the extension while on mint.com, then clicking "Edit CSS" at the bottom, and then pasting it in.


#brokerage-link {
    display: none;
}

#filters-wrapper {
    border-radius: 0px;
    box-shadow: none;
    margin-left: 40px;
}

#filters-wrapper.closed {
    border: 0px;
    border-bottom: 0px solid lightgray;
    margin-bottom: 25px;
}

#filters-wrapper.open {
    border: 0px;
    border-bottom: 1px solid lightgray;
}

#graphSelectionNav {
    width: 100%;
}

#graphSelectionNav ul li {
}

#ira-link {
    display: none;
}

#menu-category li.active, #menu-categoryTypeFilter li.active {
    border-radius: 0px;
}

#menu-category ul {
    border-radius: 0px;
}

#menu-compare ul {
    border-radius: 0px;
}

#menu-compare ul li.active {
    border-radius: 0px;
}

#module-accounts ul li h3 {
    background: none;
    border: none;
    border-bottom: 1px solid #DFDFDF;
    box-shadow: none;
}

#module-advice {
    display: none;
}

#module-budget table div.bar {
    background: none;
    background-color: #ededed;
    border-radius: 0px;
    height: 20px;
}

#module-budget table div.bar span {
    background: none;
    background-color: #3FAF3B;
    border: none;
    border-radius: 0px;
    font-weight: normal;
    padding-bottom: 4px;
    padding-top: 3px;
    text-shadow: none;
}

#module-budget table tr {
    height: 40px;
}

#module-budget table tr.overbudget div.bar span {
    background: none;
    background-color: #ED5D51;
}

#module-budget table tr.warning div.bar span {
    background: none;
    background-color: #EFBE2E;
}

#module-budget thead th.bar {
    width: 70%;
}

#module-budget.module table thead th.budget {
    padding: 0 11px;
}

#module-goals table th.name {
    width: 40%;
}

#module-goals table th.next-step {
    width: 40%;
}

#module-investments table tr {
    height: 40px;
}

#module-offers {
    display: none;
}

#month-line {
    display: none;
    height: 500px;
}

#overview-left-column {
    margin: 0px;
    width: 302px;
}

#planning_group {
    padding: 5px 0 10px 250px;
}

#pop-categories, #pop-rules, #pop-tags, #pop-hotspot-overlay {
    border-radius: 0px;
}

#rollover-link {
    display: none;
}

#search-filters small {
    border-radius: 0px;
}

#transaction-ad {
    display: none;
}

#trust {
    display: none;
}

#txn-column-accounts {
    min-width: 240px;
    width: 20%;
}

#txn-detail {
    background: none;
}

#txnEdit #actions {
    left: 698px;
}

#txnEdit-basic tbody td.date, #txnEdit-basic-multi tbody td.date {
    max-width: 12%;
}

#txnEdit-form fieldset, #txnEdit-form-multi fieldset {
    width: 726px;
}

#txnEdit-form, #txnEdit-form-multi {
    top: 48px;
    width: 765px;
}

#txnEdit-mt-account label.txn-edit-labels.checknumber {
    width: 90px;
}

#txnEdit-note, #txnEdit-note-multi {
    width: 588px;
}

#txnEdit-split-icon {
    margin-left: -9px;
}

#txnEdit-toggle.noattachcol, #txnEdit-toggleP {
    left: 350px;
    width: 765px;
}

#ways_to_invest_control {
    display: none;
}

#wrapper {
    width: 1200px;
}

.custom-filters-action-wrapper {
    left: -130px;
    top: 10px;
}

.filters-top-line {
    display: none;
}

.module .module-menu .menu-wrapper {
    border-radius: 0px;
}

.module-reminders-content .timeline .chart .date {
    width: 25px;
}

.module-reminders-content .timeline .chart .dates {
    width: 810px;
}

.module-reminders-content .timeline .chart .divider-line {
    width: 830px;
}

.module-reminders-content .timeline .chart .graph {
    background: none;
    background-color: #3FAF3B;
    border-radius: 0px;
}

.nav #activeMenuItemGreenBar {
    width: 238px;
}

.overview {
    width: 100%;
}

.overviewPage .column-left {
    box-shadow: none;
}

.overviewPage .column-main {
    width: 95%;
}

.overviewPage .module .module-menu {
    left: 823px;
}

.pageContents > div {
    width: 100%;
}

.planningPage #incomeEE-list ul.ee_header {
    padding-bottom: 0px;
}

.planningPage #timeline {
    padding: 15px 0 5px 260px;
}

.planningPage .allocate_to_goals a.button {
    background: none;
    border-radius: 0px;
}

.planningPage .budget-summary {
    border-radius: 0px;
    box-shadow: none;
}

.planningPage .budget_group {
    padding: 5px 0 10px 260px;
}

.planningPage .right_col {
    width: 310px;
}

.planningPage div.ee_list ul.ee_header {
    padding-bottom: 0px;
}

.planningPage div.leftcolumn {
    width: 240px;
}

.planningPage ul.planning_items .edit-details {
    padding: 8px 0 0 1px;
}

.planningPage ul.planning_items .over-under-budget-text {
    margin: 6px 4px 0 0;
}

.planningPage ul.planning_items div.status span.progress_bar {
    background: none ;
    background-color: #3FAF3B ;
    border: none ;
    border-radius: 0px ;
    font-weight: normal ;
    padding-bottom: 4px ;
    padding-top: 3px ;
    text-shadow: none ;
}

.planningPage ul.planning_items div.status span.total_bar {
    background: none ;
    background-color: #ededed ;
    border-radius: 0px ;
    height: 20px ;
}

.planningPage ul.planning_items li {
    height: 70px;
}

.planningPage ul.planning_items li div.status span.progress_bar.full, .planningPage #incomeBudget-list-body li.overbudget div.status span.progress_bar.full {
    background-color: #ED5D51 ;
}

.planningPage ul.planning_items li.hover {
    background: none;
    padding: 7px 35px 0px 12px;
}

.planningPage ul.planning_items li.warning div.status span.progress_bar {
    background-color: #EFBE2E ;
}

.productPageContent {
    width: 100%;
}

.txnEdit-btn {
    border-radius: 2px;
}

a#txnEdit-category_picker.noattachcol, a#txnEdit-category_picker-multi.noattachcol, a#txnEdit-category_picker, a#txnEdit-category_picker-multi {
    left: 600px;
    top: 15px;
}

a.find_all span.find_all_wrapper {
    background: none;
}

a.find_all, a.split {
    background: none;
    border: 1px solid #D8D8D8;
    margin-bottom: 5px;
    margin-top: 10px;
    padding-bottom: 10px;
    padding-left: 10px;
}

a.find_all:hover, a.split:hover {
    background-color: #D8D8D8;
}

body div#graph-container {
    padding-left: 80px;
}

div#column-accounts.column {
    width: 100%;
}

div#column-accounts.column ul li div.result-number {
    border-radius: 0px;
    left: 227px;
}

div#column-accounts.column ul li li {
    padding: 10px 10px;
}

div#column-transactions div.controls#controls-top a.button {
    border-radius: 0px;
}

div#flash-container {
    margin-left: 10px;
    padding-left: 90px;
}

div#main {
    width: 1200px;
}

div#main.trends-main {
    width: 100%;
}

div.column#column-accounts ul li, div.column#column-accounts ul li li {
}

div.column#column-content {
    width: 900px;
}

div.column#column-transactions {
    width: 98%;
}

div.inspector {
    border-radius: 0px;
}

div.left-nav {
    width: 240px;
}

div.pop.newpop {
    border-radius: 0px;
}

div.premium-filters {
    width: 850px;
}

div.right-column {
    box-shadow: none;
    width: 945px;
}

div.txn-edit-group {
    width: 598px;
}

table.account {
    width: 100%;
}

table.transactions {
    width: 766px
;
}

table.transactions tbody td {
    padding: 12px 4px 12px 3px;
}

td.column.accounts {
    border-right: 1px solid #E1E6DD;
    box-shadow: none;
    width: 240px;
}

td.column.details {
    background: none;
}

td.column.details-budgets {
    background: none;
}

td.column.transactions {
    width: 70%;
}

ul.horizontal-bar li {
    background: none;
    background-color: #3FAF3B;
    border-radius: 0px;
}

ul.horizontal-bar li.debt {
    background: none;
    background-color: #ED5D51;
    border-radius: 0px;
}

ul.vertical-bar li a {
    background: none;
    background-color: #3FAF3B;
    border-radius: 0px;
}

ul.vertical-bar li a.debt {
    background: none;
    background-color: #ED5D51;
    border-radius: 0px;
}

Tuesday, September 9, 2014

OS X Fuse Input/output error Fix

If you're using OS X Fuse to mount a remote disk on a Mac device, you will occasioanlly receive the following error:

ssh: Input/output error

This has happened to me several times when allowing my Mac to sleep with the disk still mounted. When this happens, any operation on the disk seems to fail. I've managed to fix it with the following steps:

1) Shut down the remote server / disconnect it to prevent corruption (optional)
2) Attempt to unmount the disk cleanly from your Mac: umount /tmp/ssh (where /tmp/ssh is the location of the mounted disk)
3) If that fails, find the process ID of the SSHFS process: ps aux | grep sshfs
4) Kill that process: sudo kill <PID>
5) Remove the old folder: rmdir /tmp/ssh  (rm -rf /tmp/ssh if it fails)
6) Remount everything again:

 mkdir /tmp/ssh
 sshfs user@host:/ /tmp/ssh -ocache=no -onolocalcaches -ovolname=ssh

 This should fix the Input/Output errors and allow you to cleanly remount.

Sunday, September 7, 2014

Monitoring a Scaling Infrastructure at Aviary

I recently wrote a blog post for Aviary, where I am employed as a Server Engineer. It details how we setup monitoring to automatically scale with our infrastructure and covers tools like Nagios, StatsD, CollectD, and Graphite:

Monday, September 1, 2014

Why Security is Important for Developer Operations

After working at my current gig for about a year now (internship plus full-time), I wanted to take some time to outline my experiences transitioning to more of a developer operations role from my existing security background. The transition has been fairly straight-forward, as much of the work I do currently touches security in some aspect. However, the biggest point I've noticed is how much security considerations are involved when developing tools for a traditional developer operations requirement.

While I am a big proponent of at least some security training for everyone in a technical role, it remains to be seen just how much is "enough." Obviously, as the realm of technical fields continues to expand at its current pace, having every member of a technical team fully trained in the security of the applications they are developing is impossible. Yet it is also imperative that they at least understand the risks associated with these applications; doing so should be a requirement of a good developer.

As a "Developer Operations Engineer" (a role whose title is still rather undefined and unstandardized), I generally focus on several categories of projects: infrastructure development, monitoring and incident response, and deployments and the application lifecycle. While this is a highly compressed view of my role, each of these has a dizzying array of security concerns. While some companies offload much of these concerns to a security team, smaller companies need to remain vigilant of their impact.

In most modern startup environments, infrastructure development typically refers to everyone's favorite buzzword: the cloud. Amazon Web Services, Microsoft Azure, Google's App Engine, the list goes on. The security concerns associated with the cloud are not the focus of this post, but I do want to highlight places where security is especially important. Almost every one of these services has security enhancements that are not used as often as they should be. For example, AWS's Virtual Private Cloud is not only free, but can also greatly improve security when used properly. Yet quickly starting instances from EC2 still requires less hassle and so remains the more common choice. Another example is the use of security groups. AWS's security groups are infinitely customizable, yet simply opening a port to the world (0.0.0.0) is a tempting simpler option. While hosted infrastructure providers like Amazon and Google abstract a lot of security work away from the customer, good security practices still require active participation.

Monitoring and incident response is perhaps the area in which a lack of security can have the biggest impact. While many "DevOps" engineers view monitoring in terms of system performance, monitoring must also cover system security. Disk space, CPU utilization, and memory usage are all important indicators of a healthy system, but so too are login attempts, changes to file permissions, and unauthorized outgoing network connections. A good monitoring platform must also monitor for security events that could signal an intrusion or potential breach of security. In the same light, the response to a security event should also contain a viable plan for mitigating the same risk in the future.

Finally, the deployment of applications is a critical component of the security of an infrastructure. Because the main goal of deployments from a developer operation's standpoint is automation, any security bugs introduced once tend to be replicated. For this reason, it is imperative that the deployment process and any actors in it (Jenkins, AWS S3, etc.) are fully secured and audited often. Vulnerabilities that are present here can expand exponentially when deployments are pushed.

The role of developer operations or server engineering is rapidly changing and expanding. While it does, it is important, if not necessary, to include security in the expansion and ensure that those building a company's most critical technological parts are also trained in protecting them.