The "state" param from the URL and session do not match - facebook

Question

In facebook documantion
require('include/facebook/autoload.php'); //SDK directory
$fb = new Facebook\Facebook([
'app_id' => '***********',
'app_secret' => '***********************'
]);
$helper = $fb->getRedirectLoginHelper();
$permissions = ['email', 'public_profile']; // optional
$loginUrl = $helper->getLoginUrl('http://www.meusite.com.br/login-callback.php', $permissions);
When direct it to the url $loginUrl, the return is:
Facebook SDK returned an error: Cross-site request forgery validation failed. The "state" param from the URL and session do not match

Answer 1

I had the same error.
The problem occurred because I did getLoginUrl(...) before getAccessToken()
So rid of getLoginUrl(...) in redirected URL and code should works.

Answer 2

I had the same issue and for me that error was occurring because I did not put session_start(); in my login.php page code before calling getLoginUrl(..) and also at the top of login-callback.php page.
Just put session_start(); in your "login" page and "login-callback" page and it will work surely just like it is working for me now.

Answer 3

There could be 2 reason for this error:
you didn't call session_start(); before getLoginUrl call
You executed getLoginUrl again in login-callback.php, so state value regenerated and mismatched with the redirected value

Answer 4

Possible Fixes : I used the following configuration settings .
Enable WebAuthLogin under the advanced tab . Provide the url in the WebAuthLogin settins as same as that you provide in $loginUrl ;
For example if you use $loginUrl as https://example.com/ use that same in the WebAuthlogin Url
$loginUrl = $helper->getLoginUrl('https://example.com/', $permissions);

Answer 5

This problem occures also in case that you generate 2 or more login links on the same page (e.g. one for login and other for registration - even both point to the same url, they have just different labels).
Facebook SDK creates/updates $_SESSION[FBRLH_state] for each new generated loginURL. So if there are 2 generated URLs (using $helper->getLoginUrl()) then the $_SESSION[FBRLH_state] is 2-times rewritten and valid only for the last generated URL. Previous login URL becomes invalid. It means that it is not possible to generate 2 valid loginURLs. In case that 2 same URLs are generated then return the first one and avoid call of Facebook SDK for generation of second one.

Answer 6

I had the same problem.
The reason for this error is because --->
When "$helper->getLoginUrl" calls, it create a session variable "FB_State", and this is something to FB uses to match the token. Every-time getLoginUrl calls, it create new state. Then after user authorized and redirect back, if you codes cannot detect this event and re-run "$helper->getLoginUrl", then this error will occur.
The solution ->
refine your coding, stop run "$helper->getLoginUrl" again if authorized.
if you already rerun, then set the session variable for the token to NULL if you have, then User can re-authorize again.
when user tries re-authorize, they can remove the authorized APP once or you need to generate new link with "$helper->getReRequestUrl"
Yet, token has be called by "getAccessToken()" before the "$helper->getLoginUrl" or "$helper->getReRequestUrl" runs.
Good Luck!!!!!

Answer 7

Finally, looking into FB code, I discovered that the problem "Cross-site request forgery validation failed. Required param “state” missing" and similars are caused by PHP variable $_SESSION['FBRLH_state'] that for some "strange" reason when FB call the login-callback file.
To solve it I store this variable "FBRLH_state" AFTER the call of function $helper->getLoginUrl(...). Is very important to do only after the call of this function due to is inside this function when the variable $_SESSION['FBRLH_state'] is populated.
Below an example of my code in the login.php:
$uri=$helper->getLoginUrl($uri, $permissions);
foreach ($_SESSION as $k=>$v) {
if(strpos($k, "FBRLH_")!==FALSE) {
if(!setcookie($k, $v)) {
//what??
} else {
$_COOKIE[$k]=$v;
}
}
}
var_dump($_COOKIE);
And in the login-callback.php before calling all FB code:
foreach ($_COOKIE as $k=>$v) {
if(strpos($k, "FBRLH_")!==FALSE) {
$_SESSION[$k]=$v;
}
}
Last, but not least, remember also to include code for PHP session so..
if(!session_id()) {
session_start();
}
...
...
...
...
<?php session_write_close() ?>
I hope this response can help you to save 8-10 hours of work :)
Bye, Alex.

Answer 8

This issue was a bit confusing for me, because I had to change a line at the facebook src file:
src/Facebook/Helpers/FacebookRedirectLoginHelper.php
at the function: "validateCsrf" like this:
if ($result !== 0) {
throw new FacebookSDKException('Cross-site request forgery validation failed. The "state" param from the URL and session do not match.');
}
And change it into:
if ($result === 0) {
throw new FacebookSDKException('Cross-site request forgery validation failed. The "state" param from the URL and session do not match.');
}
I don't know if this makes a violation to the facebook SDK security, so I truly opened to any exlanation or recommendation for this answer.
You may also make the following changes at the facebook app manager:
add your site and callback-url into your facebook app account at:
setting->advanced:Valid OAuth redirect URIs
Don't forget to add another url with slash (/) at the end of each url and check all 4 checkboxes at Client OAuth Settings.

Answer 9

I had the same error. Are you using 1 file or 2? I was trying to get by using 1 file but my error was resolved when I split into login.php & fb-callback.php as the documentation recommended. My sessions were being re-written so the state was never saved properly.
Good luck!

Answer 10

Happens when the session in missing a needed variable.
might be caused by several things.
In my case I left the "www" out of the callback URL

Answer 11

You could actually be parsing the data from another domain... for example:
website.com is different from www .website.com
If you're parsing data from http ://website.com/login.php to http://www.website.com/fb-callback.php this would be a cross-domain problem and the error you are receiving would be because of that....
http ://website.com and http ://www.website.com are the same but the script identifies them as different..... hope that gives insight to the problem.