(PowerShell) Azure OpenID Connect Step 2 -- Get id_token and Validate

See more OIDC Examples

After getting the endpoints by querying the Azure's OIDC well-known discovery document (OpenID Configuration document), we use the authorization_endpoint to get the id_token, and then validate it..

For more information, see https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-protocols-oidc

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# In our previous example (Azure Fetch OpenID Connect metadata document) we fetched
# the OpenID configuration document which is JSON which contains an entry for authorization_endpoint.

$authorization_endpoint = "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/oauth2/v2.0/authorize"

# The OpenID Connect metadata document also contained a jwks_uri entry.  This is the JSON Web Key Set (JWKS),
# which is a set of keys containing the public keys used to verify any JSON Web Token (JWT) (in this case the id_token)
# issued by the authorization server and signed using the RS256 signing algorithm. 
$jwks_uri = "https://login.microsoftonline.com/6d8ddd66-68d1-44b0-af5c-e31b4b7ee5cd/discovery/v2.0/keys"

# We're going to send the following GET request, but it will be sent through an interactive web browser (not by Chilkat).
# The following code will form the URL that is to be programmatically loaded and sent in a browser.

# GET https://login.microsoftonline.com/{tenant}/oauth2/v2.0/authorize?
# client_id=6731de76-14a6-49ae-97bc-6eba6914391e
# &response_type=id_token
# &redirect_uri=http%3A%2F%2Flocalhost%2Fmyapp%2F
# &response_mode=form_post
# &scope=openid
# &state=12345
# &nonce=678910

# Use this object to set params and then get the URL-encoded query params string 
$req = New-Object Chilkat.HttpRequest
$req.AddParam("client_id","f125d695-c50e-456e-a579-a486f06d1213")
$req.AddParam("response_type","id_token")
$req.AddParam("redirect_uri","http://localhost:3017/")
$req.AddParam("response_mode","form_post")
$req.AddParam("scope","openid")
$prng = New-Object Chilkat.Prng
$req.AddParam("state",$prng.GenRandom(3,"decimal"))
$req.AddParam("nonce",$prng.GenRandom(4,"decimal"))

$encodedParams = $req.GetUrlEncodedParams()
$($encodedParams)

# Sample URL encoded params:
# client_id=6731de76-14a6-49ae-97bc-6eba6914391e&redirect_uri=http%3A%2F%2Flocalhost%3A3017%2F&response_mode=form_post&scope=openid&state=3572902&nonce=57352474

# This is the URL to be programmatically loaded and sent in an interactive web browser..
$sbUrl = New-Object Chilkat.StringBuilder
$sbUrl.Append($authorization_endpoint)
$sbUrl.Append("?")
$sbUrl.Append($encodedParams)
$url = $sbUrl.GetAsString()

# Before we launch the browser with the contents of sbUrl, create a socket to listen for the eventual callback..

$listenSock = New-Object Chilkat.Socket

# Listen at the port indicated by the redirect_uri above.
$backLog = 5
$success = $listenSock.BindAndListen(3017,$backLog)
if ($success -ne $true) {
    $($listenSock.LastErrorText)
    exit
}

# Wait for the browser's connection in a background thread.
# (We'll send load the URL into the browser following this..)
# Wait a max of 60 seconds before giving up.
$maxWaitMs = 60000
$task = $listenSock.AcceptNextConnectionAsync($maxWaitMs)
$task.Run()

# -------------------------------------------------------------------
# At this point, your application should load the URL in a browser.
# You'll need to add code here to do it..

# For example, 
# in C#: System.Diagnostics.Process.Start(url);
# in Java: Desktop.getDesktop().browse(new URI(url));
# in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
#              wsh.Run url
# in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
# in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
# The account owner would interactively accept or deny the authorization request.

# Add the code to load the url in a web browser here...
# Add the code to load the url in a web browser here...
# Add the code to load the url in a web browser here...
# System.Diagnostics.Process.Start(url);

# -------------------------------------------------------------------

# Wait for the listenSock's task to complete.
$success = $task.Wait($maxWaitMs)
if (!$success -or ($task.StatusInt -ne 7) -or ($task.TaskSuccess -ne $true)) {
    if (!$success) {
        # The task.LastErrorText applies to the Wait method call.
        $($task.LastErrorText)
    }
    else {
        # The ResultErrorText applies to the underlying task method call (i.e. the AcceptNextConnection)
        $($task.Status)
        $($task.ResultErrorText)
    }

    exit
}

# If we get to this point, a connection on listenSock was accepted, and the redirected POST
# is waiting to be read on the connected socket.
# The POST we are going to read contains the following:

# POST /myapp/ HTTP/1.1
# Host: localhost
# Content-Type: application/x-www-form-urlencoded
# 
# id_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCI6Ik1uQ19WWmNB...&state=12345

# But first.. we no longer need the listen socket...
# Stop listening on port 3017.
$listenSock.Close(10)

# Get the connected socket.
$sock = New-Object Chilkat.Socket
$sock.LoadTaskResult($task)

# We're acting as a temporary web server to receive this one redirected HTTP request..
# Read the start line of the request.. (i.e. the "POST /myapp/ HTTP/1.1")
$startLine = $sock.ReceiveUntilMatch("`r`n")
if ($sock.LastMethodSuccess -ne $true) {
    $($sock.LastErrorText)
    exit
}

# Read the request header.
$requestHeader = $sock.ReceiveUntilMatch("`r`n`r`n")
if ($sock.LastMethodSuccess -ne $true) {
    $($sock.LastErrorText)
    exit
}

$($requestHeader)
$("----")

# Read the body.
# The body will contain "id_token= eyJ......"
$sbRequestBody = New-Object Chilkat.StringBuilder
$success = $sock.ReceiveSb($sbRequestBody)
if ($success -eq $false) {
    $($sock.LastErrorText)
    exit
}

$($sbRequestBody.GetAsString())

# Given that we're acting as a web server, we must send a response..
# We can now send our HTTP response.
$sbResponseHtml = New-Object Chilkat.StringBuilder
$sbResponseHtml.Append("<html><body><p>Thank you!</b></body</html>")

$sbResponse = New-Object Chilkat.StringBuilder
$sbResponse.Append("HTTP/1.1 200 OK`r`n")
$sbResponse.Append("Content-Length: ")
$sbResponse.AppendInt($sbResponseHtml.Length)
$sbResponse.Append("`r`n")
$sbResponse.Append("Content-Type: text/html`r`n")
$sbResponse.Append("`r`n")
$sbResponse.AppendSb($sbResponseHtml)

$sock.SendString($sbResponse.GetAsString())
$sock.Close(50)

# Get the id_token from the sbRequestBody that we just received.
# (Remember, we're acting as the web server, thus we received the redirect request..)
$hashTab = New-Object Chilkat.Hashtable
$hashTab.AddQueryParams($sbRequestBody.GetAsString())

# See https://docs.microsoft.com/en-us/azure/active-directory/develop/id-tokens#validating-an-id-token
# for more information about ID tokens..
$idToken = $hashTab.LookupStr("id_token")

$jwt = New-Object Chilkat.Jwt

# Let's see if the time constraints, if any, are valid.
# The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
# If the current system time is before the "nbf" time, or after the "exp" time,
# then IsTimeValid will return false/0.
# Also, we'll allow a leeway of 60 seconds to account for any clock skew.
# Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
$leeway = 60
$bTimeValid = $jwt.IsTimeValid($idToken,$leeway)
$("time constraints valid: " + $bTimeValid)

# Now let's recover the original claims JSON (the payload).
$payload = $jwt.GetPayload($idToken)
# The payload will likely be in compact form:
$($payload)

# We can format for human viewing by loading it into Chilkat's JSON object
# and emit.
$json = New-Object Chilkat.JsonObject
$success = $json.Load($payload)
$json.EmitCompact = $false
$($json.Emit())

# Sample output:

# {
#   "aud": "f125d695-c50e-456e-a579-a486f06d1213",
#   "iss": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0",
#   "iat": 1626535322,
#   "nbf": 1626535322,
#   "exp": 1626539222,
#   "aio": "AWQAm/8TAAAAHQncmY0VvhgyMIhfleHX3DjsGfmlPM1CopkJ3mPnBUnCxrJ0ubruaACEhwGO7NsoHBhqFEzRzPxOq7MtuGVFsql+qJKZx8vQCszKYEPX9Wb3b5+d5KJTABHCIH48bTFd",
#   "idp": "https://sts.windows.net/9188040d-6c67-4c5b-b112-36a304b66dad/",
#   "nonce": "1519043321",
#   "rh": "0.ARgAZt2NbdFosEOvXOMbS33VzZXWJfEOxW5FpXmkhvBtEhMYALQ.",
#   "sub": "RMIZlHJ7hfsJmL8Qq3h6M0nPi4g-HEavnAFgxzaT2KM",
#   "tid": "6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd",
#   "uti": "-BXGHxvfREW-r9HI5NBiAA",
#   "ver": "2.0"
# }

# We can recover the original JOSE header in the same way:
$joseHeader = $jwt.GetHeader($idToken)
# The payload will likely be in compact form:
$($joseHeader)

# We can format for human viewing by loading it into Chilkat's JSON object
# and emit.
$jsonJoseHeader = New-Object Chilkat.JsonObject
$success = $jsonJoseHeader.Load($joseHeader)
$jsonJoseHeader.EmitCompact = $false
$($jsonJoseHeader.Emit())

# Sample output:

# {
#   "typ": "JWT",
#   "alg": "RS256",
#   "kid": "nOo3ZDrODXEK1jKWhXslHR_KXEg"
# }

# Finally, we need to fetch the JSON Web Key Sets from the jwks_uri
# and use it to verify the id_token's RSA signature.
$sbJwks = New-Object Chilkat.StringBuilder
$http = New-Object Chilkat.Http
$success = $http.QuickGetSb($jwks_uri,$sbJwks)
if ($success -eq $false) {
    $($http.LastErrorText)
    exit
}

$jwkset = New-Object Chilkat.JsonObject
$success = $jwkset.LoadSb($sbJwks)
$jwkset.EmitCompact = $false
$($jwkset.Emit())

# A sample jwkset:

# {
#   "keys": [
#     {
#       "kty": "RSA",
#       "use": "sig",
#       "kid": "nOo3ZDrODXEK1jKWhXslHR_KXEg",
#       "x5t": "nOo3ZDrODXEK1jKWhXslHR_KXEg",
#       "n": "oaLLT9hkcSj ... NVrZdUdTBQ",
#       "e": "AQAB",
#       "x5c": [
#         "MIIDBTC ... MRku44Dw7R"
#       ],
#       "issuer": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0"
#     },
#     {
#       "kty": "RSA",
#       "use": "sig",
#       "kid": "l3sQ-50cCH4xBVZLHTGwnSR7680",
#       "x5t": "l3sQ-50cCH4xBVZLHTGwnSR7680",
#       "n": "sfsXMXW ... AYkwb6xUQ",
#       "e": "AQAB",
#       "x5c": [
#         "MIIDBTCCA ... BWrh+/vJ"
#       ],
#       "issuer": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0"
#     },
#     {
#       "kty": "RSA",
#       "use": "sig",
#       "kid": "DqUu8gf-nAgcyjP3-SuplNAXAnc",
#       "x5t": "DqUu8gf-nAgcyjP3-SuplNAXAnc",
#       "n": "1n7-nWSL ... V3pFWhQ",
#       "e": "AQAB",
#       "x5c": [
#         "MIIC8TC ... 9pIcnkPQ=="
#       ],
#       "issuer": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0"
#     },
#     {
#       "kty": "RSA",
#       "use": "sig",
#       "kid": "OzZ5Dbmcso9Qzt2ModGmihg30Bo",
#       "x5t": "OzZ5Dbmcso9Qzt2ModGmihg30Bo",
#       "n": "01re9a2BU ... 5OzQ6Q",
#       "e": "AQAB",
#       "x5c": [
#         "MIIC8TC ... YmwJ6sDdRvQ=="
#       ],
#       "issuer": "https://login.microsoftonline.com/6d8ddd66-68d1-43b0-af5c-e31b4b7dd5cd/v2.0"
#     }
#   ]
# }

# We should have an RSA key with kid matching the kid from the joseHeader..
$kid = $jsonJoseHeader.StringOf("kid")

# Find the RSA key with the specified key id
$jwk = $jwkset.FindRecord("keys","kid",$kid,$true)
if ($jwkset.LastMethodSuccess -eq $false) {
    $("Failed to find a matching RSA key in the JWK key set...")
    exit
}

$pubkey = New-Object Chilkat.PublicKey

$success = $pubkey.LoadFromString($jwk.Emit())
if ($success -eq $false) {
    $($pubkey.LastErrorText)
    $($jwk.Emit())
}
else {
    $verified = $jwt.VerifyJwtPk($idToken,$pubkey)
    $("Verified: " + $verified)
}