DEV Community

Dealing with Chrome SameSite cookie attribute in Shopify Apps made with PHP/Laravel

Zubair Mohsin on February 13, 2020

Prerequisite Read this extensive tutorial from Shopify to get more understanding about the SameSite cookie attribute. Working with Same...

Read full post

Rowan Merewood • Feb 18 '20

Nice article! For the benefit of anyone reading who didn't take your advice and fully understand the issues first ;) Please, please, please remember you ONLY need SameSite=None; Secure for cookies that are sent in cross-site / third-party contexts. So, that means these embedded apps or services. Cookies for first-party use, i.e. the domain in the browser matches the domain of the cookie, then consider SameSite=Lax or SameSite=Strict instead. Do not just blindly add SameSite=None; Secure to every single cookie.

Jasper Frumau • Jul 5 '20

So for the Laravel session and XSRF Token cookies we should use SameSite="Strict at config/session.php? How would we implement this and only have this apply for these two cookies I am now getting warnings for?

cookie `host-name_staging_session` will be soon rejected because it has
 the “sameSite” attribute set to “none” or an invalid value, without the “secure” attribute. To know more about the “sameSite“ attribute, read
 https://developer.mozilla.org/docs/Web/HTTP/Headers/Set-Cookie/SameSite 1748

Rowan Merewood • Jul 5 '20

I'd suggest Lax for your session cookie, not Strict.

Daniel P 🇨🇦 • Feb 13 '20 • Edited

Very timely post :) Just wanted to note some of my findings.

Chrome 80, as it's being updated across our computers, likely does not break your site/app.

Due to the safari bug, they put in an exception

Chrome will make an exception for cookies set without a SameSite attribute less than 2 minutes ago.

(link: chromestatus.com/feature/508814734...)

However, Safari seems to have been broken for a while now, so a fix should be implemented quickly.

(link: bugs.webkit.org/show_bug.cgi?id=19...)

Their solution uses an Apache regex to solve the problem, but the solution is not up to date with latest Safari.

On a side note, if you've using an SPA and JWTs (no cookies) this is a non-issue.

Rowan Merewood • Feb 18 '20

That exception is temporary and will go away at some point. The specific situation that covers is for top-level, cross-site POST requests that require cookies. These should be set with SameSite=None; Secure as a permanent fix, not rely on the exception. This was added to account for a number of individual single sign-on implementations using this pattern to receive a CSRF token in their cookie - it is not related to the Safari issue.

The Safari issue is due to their implementation matching a much earlier version of the draft. As a result, if you need the cookie to work in all browsers you can use the double cookie solution proposed in web.dev/samesite-cookie-recipes/#h...

Zubair Mohsin • Feb 18 '20

Thank you Rowan for your input on this issue 🙏🏼

Zubair Mohsin • Feb 13 '20

Hi Daniel, thank you for sharing your findings.

SameSite flag is not being enforced even in Chrome 80 until 17th February, 2020. ( I am not sure about the date ) as a relaxation.

If you want to test, go to chrome://flags and enable all three SameSite flags. You will see the errors mentioned in Shopify's tutorial.

All we can do, is to be prepared, right? ;)

And yeah, you are right about SPA. 👍

Let me know your thoughts! Thanks.

David Orr • Oct 12 '20

Why is it necessary to check the browser and only set the SameSite/Secure attributes for compatible clients? Would something bad happen if you just set it in your config/session.php and used it for all users? Any clients that do not recognize SameSite=None should ignore it and carry on as if the attribute was not set.

Wajahat Anwar • Mar 16 '20

One more thing I discovered. We can't set SameSite = None in laravel 5.6 or lower version. SameSite = Lax works in laravel 5.6 But we can set SameSite = NONE in 5.8 or above.

Wajahat Anwar • Mar 7 '20

This tutorial was super helpful and it is straight and to the point. Thanks, Mohsin for sharing this.

jayShopTO • Mar 11 '20

Thank you for making this and helping the community.