How can I verify firebase token server side? - php

I have a firebase account where I manually create the users who will be abled to use my site (sign up is not public, but it is not relevant to this inquiry)
In the login page, the authentication is through javascript.
Once the user enters their mail and password the corresponding function is executed, I get the token and I send it to my PHP server via url redirection. Something like this:
firebase.auth().signInWithEmailAndPassword(inputemail, inputpassw)
.then( function(user) {
myEmail = user.email;
myUid = user.uid;
user.getIdToken()
.then( function(token){
myToken = token;
location.href = "http://www.example.com/verify?email="+myEmail+"&token="+myToken+"&uid="+myUid;
});
}, function (error) {
...
});
Then, on my server I will have the mail, the uid, and the token.
So, my question is:
How do I verify that the token is valid? It is impossible?
I know the token is encrypted, but the key is public... so anyone could make a valid token!
I mean, for instance, I have an expired token, I can decode it, change the expiration time, encode it again and gain access to my server without knowing any password
Is there something I'm missing?
Apparently I can not verify the token via REST.
What alternative do I have?

From the Firebase Documentation:
The Firebase Admin SDK has a built-in method for verifying and decoding ID tokens. If the provided ID token has the correct format, is not expired, and is properly signed, the method returns the decoded ID token. You can grab the uid of the user or device from the decoded token.
So, you do not need to worry about someone trying to generate fake tokens.
To verify the token in PHP, as described in the docs Firebase Admin SDK for PHP
Minimal code for verifying the token:
use Kreait\Firebase;
use Firebase\Auth\Token\Exception\InvalidToken;
//create Firebase factory object
//$firebase = (new Firebase\Factory())->create();
//get a token from client
//$idTokenString = 'eyJhbGciOiJSUzI1...';
try {
$verifiedIdToken = $firebase->getAuth()->verifyIdToken($idTokenString);
} catch (InvalidToken $e) {
echo $e->getMessage();
}
$uid = $verifiedIdToken->getClaim('sub');
$user = $firebase->getAuth()->getUser($uid);
echo $user;

Related

Storing the Google OAuth Authorization Token in Database

I am building a portal where multiple users can log in to their multiple Gmail accounts. I have successfully retrieved the token value, However, I want to store that in my database but I am unable to store it.
Below is the code I am using:
function mInititalize(){
$client = new Google_Client();
$client->addScope('https://www.googleapis.com/auth/plus.login https://www.googleapis.com/auth/userinfo.email https://mail.google.com/');
$client->setClientId(Config('gmail.client_id'));
$client->setClientSecret(Config('gmail.client_secret'));
$client->setRedirectUri('http://localhost:81'.Config('gmail.redirect_url'));
$loginURL = $client->createAuthUrl();
return redirect($loginURL);
}
After Redirection or user login
function mGetToken(){
$token = $client->fetchAccessTokenWithAuthCode( 'code'); // here i get the 'code' from login URL
I pass this code to get token I successfully get token
$oAuth = new Google_Service_Oauth2( $client);
$userData = $oAuth->userinfo_v2_me->get(); // get current user detail
}
I want to store $token value in database, but I am getting error message
>Serialization of 'Closure' is not allowed
Please anyone help me to solve this issue. Thanks.
I would suggest storing OAuth credential information for the Google API, not in your database, but through the API itself. If you're intending to use it any authentication manner, you'll run into problems, as the docs state:
Access tokens periodically expire and become invalid credentials for a related API request. Google Identity Platform: Using OAuth 2.0 for Web Server Applications
But, the same docs also show a way that you can set or retrieve the token natively within the API. Since it's data relating to google's auth'ing process, and since it might go stale if you store it, it seems best to just let them handle it and work with the API. The same source:
If you need to apply an access token to a new Google_Client object—for example, if you stored the access token in a user session—use the setAccessToken method:
$client->setAccessToken($access_token);
$client->getAccessToken();

How can I get this Google Login ID Token from this Android app to verify server-side?

I'm getting the ID Token in my Android app by initiating like this:
GoogleSignInOptions googleSignInOptions = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
.requestIdToken(getString(R.string.server_client_id))
.requestEmail()
.build();
Where server_client_id is my SERVER's Oauth Client ID. Then later I request the token with googleAccount.getIdToken()
Then on my server (PHP), when I verify the token I verify it like this:
$client = new \Google_Client(['client_id' => getenv("GOOGLE_CLIENT_ID")]);
try {
$payload = $client->verifyIdToken($this->idToken);
} catch (\Exception $e){
throw new BadRequestHttpException($e->getMessage());
}
if($payload){
$this->verifyPayload($payload);
} else {
throw new AccessDeniedHttpException("Invalid ID Token");
}
Where GOOGLE_CLIENT_ID is my ANDROID's Oauth Client ID
I'm following this guide: https://developers.google.com/identity/sign-in/android/start-integrating.
On this page it says: https://developers.google.com/identity/sign-in/android/backend-auth
When you configure Google Sign-in, call the requestIdToken method and pass it your server's web client ID.
Hence why I'm using the server_client_id in my Android app. Is this correct?
// Specify the CLIENT_ID of the app that accesses the backend
And this is why I'm using the ANDROID client ID from my server.
Is this right? To be using each other's Oauth client_id's? Or should they both be using the Android CLIENT_ID?
Thanks in advance
OK I figured it out. Both the Android app and Webserver need to use the SERVER's key. Even though I created a client ID for the app using it's key SHA1 and everything.
Send authorisation request from the app, using client_id and public key
As a response you get a temporary token
Send the token to your API. Use it to make another request (from the API to Google), to get a long lived token
Store the long-lived token. Use it to request data from google, f.e. user information
Important: never use server key inside the app

PHP authentication with JWT

I'm creating a sort of 'social network'. Now I'm creating the authentication part. Today I learned about JSON Web Tokens.
1) I read that JWT's are safe to use, because the are signed with a secret key. But then I found some tools online like https://jwt.io. I tried to build some JWT tokens with PHP using firebase/php-jwt. The tools like jwt.io can extract the data I put in the JWT (like user ID). How can this be safe? Can't someone just create a new JWT using the old one but with a different user ID?
An example: I created the following token:
eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJNeUFQIiwiaWF0IjoxNTE2NTYzMTM0LCJleHAiOjE1MTY1NjQzNDAsImF1ZCI6Ind3dy5leGFtcGxlLmNvbSIsInN1YiI6ImFkbWluQGV4YW1wbGUuY29tIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOiJmYWxzZSJ9.dCtYVpFXhoQmzOdX_dW1yFHEcZ9aZ1I9MC33lJGapvY
If you paste this token in jwt.io, you'll see the payload is "name: John Doe" and "admin: false". Isn't this unsafe? Or is it safe because you NEED the secret key to recreate a JWT.
Off the record: You cannot store senstive information in a JWT I guess...
2) How to "login" a user using PHP and JWT's? I created a quick demo, I'm not sure the code "works" but I guess you'll see what I mean.
if (isset($_POST['submit'])) {
$user = $_POST['user'];
$pass = $_POST['pass'];
if($user = 'my_username' && $password == 'my_password') {
// user is logged in
// create a JWT here
} else {
// wrong credentials!
}
}
Now, the question/problem is: how to store this token? In a cookie? In a session? Using HTML5's localStorage? What is the safest way to do this?
And secondly: how to authenticate the user? I would do it like this:
// my secret key
$secret = 'MY_SECRET_KEY';
// decode the token
$token = JWT::decode($token, $secret, array('HS256'));
// what to do here?
Can you match this token with some data in a database or something?
1) The JWT token is not encrypted, so the data inside it can be easily read. However, it contains a signature that can be validated only with the secret key you have set when creating the token. You can check the signature to see that the token has not been tampered with.
2) The token can be stored anywhere, since it's so small. Just remember that the token can be easily read, but not altered. Don't store any sensitive data in the tokens.
When checking the token, the important things to check are the signature and the exp time to see that the token is still valid. A well-constructed token doesn't need full database validation, but rather just check that the user's privileges haven't been changed since issuing the token, and if they have, recreate the token with the updated data or force the user to log in again.

How to implement 'Token Based Authentication' securely for accessing the website's resources(i.e. functions and data) that is developed in PHPFox?

I want to use methods and resources from the code of a website which is developed in PHPFox.
Basically, I'll receive request from iPhone/Android, I'll get the request and pass to the respective function from the PHPFox code, take the response from that function and return it back to the device.
For this purpose I've developed REST APIs using Slim framework.
But the major blocker I'm facing currently is in accessing the resources(i.e. functions and data) of PHPFox website.
I'm not understanding how should I authenticate the user using 'Token Based Authentication' in order to access the website's resources.
If someone could guide me in proper direction with some useful working example it would be really helpful for me.
N.B. : The proposed implementation of 'Token Based Authentication' should be very secure and fast in speed. The security should not be compromised in any way.
Following is the code I tried on my own but I don't know whether it's right or wrong. Is my approach correct or wrong. Please someone analyse it and let me know your feedback on it.
To create a token i use this function which takes as parameters, the user's data
define('SECRET_KEY', "fakesecretkey");
function createToken($data)
{
/* Create a part of token using secretKey and other stuff */
$tokenGeneric = SECRET_KEY.$_SERVER["SERVER_NAME"]; // It can be 'stronger' of course
/* Encoding token */
$token = hash('sha256', $tokenGeneric.$data);
return array('token' => $token, 'userData' => $data);
}
So a user can authentified himself and receive an array which contains a token (genericPart + his data, encoded), and hisData not encoded :
function auth($login, $password)
{
// we check user. For instance, it's ok, and we get his ID and his role.
$userID = 1;
$userRole = "admin";
// Concatenating data with TIME
$data = time()."_".$userID."-".$userRole;
$token = createToken($data);
echo json_encode($token);
}
Then the user can send me his token + his un-encoded data in order to check :
define('VALIDITY_TIME', 3600);
function checkToken($receivedToken, $receivedData)
{
/* Recreate the generic part of token using secretKey and other stuff */
$tokenGeneric = SECRET_KEY.$_SERVER["SERVER_NAME"];
// We create a token which should match
$token = hash('sha256', $tokenGeneric.$receivedData);
// We check if token is ok !
if ($receivedToken != $token)
{
echo 'wrong Token !';
return false;
}
list($tokenDate, $userData) = explode("_", $receivedData);
// here we compare tokenDate with current time using VALIDITY_TIME to check if the token is expired
// if token expired we return false
// otherwise it's ok and we return a new token
return createToken(time()."#".$userData);
}
$check = checkToken($_GET['token'], $_GET['data']);
if ($check !== false)
echo json_encode(array("secureData" => "Oo")); // And we add the new token for the next request
Am I right?
Thanks.
1st you should understand what's token based authentication. It could be explained as below.
The general concept behind a token-based authentication system is
simple. Allow users to enter their username and password in order to
obtain a token which allows them to fetch a specific resource -
without using their username and password. Once their token has been
obtained, the user can offer the token - which offers access to a
specific resource for a time period - to the remote site.
Read more
Now let's see what are the steps of implementing it in your REST web service.
It will use the following flow of control:
The user provides a username and password in the login form and clicks Log In.
After a request is made, validate the user on the backend by querying in the database. If the request is valid, create a token by
using the user information fetched from the database, and then return
that information in the response header so that we can store the token
browser in local storage.
Provide token information in every request header for accessing restricted endpoints in the application.
If the token fetched from the request header information is valid, let the user access the specified end point, and respond with JSON or
XML.
See the image below for the flow of control
You might be wondering what's a JWT
JWT stands for JSON Web Token and is a token format used in
authorization headers. This token helps you to design communication
between two systems in a secure way. Let's rephrase JWT as the "bearer
token" for the purposes of this tutorial. A bearer token consists of
three parts: header, payload, and signature.
The header is the part of the token that keeps the token type and encryption method, encoded in base64.
The payload includes the information. You can put any kind of data like user info, product info and so on, all of which is also stored in
base64 encoding.
The signature consists of combinations of the header, payload, and secret key. The secret key must be kept securely on the server-side.
You can see the JWT schema and an example token below;
You do not need to implement the bearer token generator as you can use php-jwt.
Hope the above explains your confusion. if you come across any issues implementing token based authentication let me know. I can help you.

How is basic authentication header validated/checked in a rest api

I'm building a very tiny api.
In the api im authenticating the request using basic authentication header coming from the request.
This is the code upto which I have done
$headers = apache_request_headers() ;
// print_r($headers);
if(isset($headers['Authorization'])){
//$credentials = base64_decode($headers);
print_r($headers['Authorization']);
}
I got the Authorization header as 'Basic YXBpa2V5OmFqZWVzaA==' Now how will I check if this basic authorization header is valid?
Should I decode the base64 string in the username:password format and check it with the DB or when the username and pass is generated,do I have to store it in a base64 format and compare the request base64 string with the one in DB??
I would like to know what is the standard practice of validating a basic authentication request?
Please suggest some ideas. I am just starting up, please excuse stupidity in questions.
i suggest you to use a api token rather than a user/password combination. with a simple auth token you get two benefits.
Usernames or Passwords may change with the time and if so the user is forced to change all usernames and passwords in his application to get there application back to work. a simple token are constant and don't require any change when the username and password of the user changed.
With basic auth the client need to send there username + password in a unencrypted format. this is not very secure and on the worst case, unauthorized can login into the service backend with username + password from the request. simple token are only valid for api calls.
Generate a simple random token for each API user like Eq57dwypZaFW4f2xxRzFaGjwCYinOn6l13Mvds00P2ZzgdMPTk and require to send this token on each api request with the request header like
X-API-TOKEN: Eq57dwypZaFW4f2xxRzFaGjwCYinOn6l13Mvds00P2ZzgdMPTk
X-API-CLIENT-ID: 123456
on the server side validate with
<?php
$token = $_SERVER['X-API-TOKEN'];
$userID = $_SERVER['X-API-CLIENT-ID'];
$isValid = $findInDatabase->findToken($userID, $token);
if( $isValid )
{
// process api request
} else {
// invalid token
}

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