/// <summary>
/// Signs JWT token using the private key and returns the serialized assertion.
/// </summary>
/// <param name="payload">the JWT payload to sign.</param>
private string CreateAssertionFromPayload(JsonWebSignature.Payload payload)
{
string serializedHeader = CreateSerializedHeader();
string serializedPayload = NewtonsoftJsonSerializer.Instance.Serialize(payload);
var assertion = new StringBuilder();
assertion.Append(TokenEncodingHelpers.UrlSafeBase64Encode(serializedHeader))
.Append('.')
.Append(TokenEncodingHelpers.UrlSafeBase64Encode(serializedPayload));
var signature = CreateSignature(Encoding.ASCII.GetBytes(assertion.ToString()));
assertion.Append('.').Append(TokenEncodingHelpers.UrlSafeEncode(signature));
return(assertion.ToString());
}
public async Task FetchesOidcToken_CorrectPayloadSent()
{
// A little bit after the tokens returned from OidcTokenFakes were issued.
var clock = new MockClock(new DateTime(2020, 5, 13, 15, 0, 0, 0, DateTimeKind.Utc));
var messageHandler = new OidcTokenResponseSuccessMessageHandler();
var initializer = new ServiceAccountCredential.Initializer("MyId", "http://will.be.ignored")
{
Clock = clock,
ProjectId = "a_project_id",
HttpClientFactory = new MockHttpClientFactory(messageHandler)
};
var credential = new ServiceAccountCredential(initializer.FromPrivateKey(PrivateKey));
var expectedPayload = new JsonWebSignature.Payload
{
Issuer = "MyId",
Subject = "MyId",
Audience = GoogleAuthConsts.OidcTokenUrl,
IssuedAtTimeSeconds = (long)(clock.UtcNow - UnixEpoch).TotalSeconds,
ExpirationTimeSeconds = (long)(clock.UtcNow.Add(JwtLifetime) - UnixEpoch).TotalSeconds,
TargetAudience = "any_audience"
};
var serializedExpectedPayload = NewtonsoftJsonSerializer.Instance.Serialize(expectedPayload);
var urlSafeEncodedExpectedPayload = TokenEncodingHelpers.UrlSafeBase64Encode(serializedExpectedPayload);
var oidcToken = await credential.GetOidcTokenAsync(OidcTokenOptions.FromTargetAudience("any_audience"));
await oidcToken.GetAccessTokenAsync();
var requestFormDict = messageHandler.LatestRequestContent.Split('&')
.ToDictionary(entry => entry.Split('=')[0], entry => entry.Split('=')[1]);
var assertion = requestFormDict["assertion"];
// Assertion format shoould be headers.payload.signature
var encodedPayload = assertion.Split('.')[1];
Assert.Contains(urlSafeEncodedExpectedPayload, encodedPayload);
}
