/
saml_sp.js
1375 lines (1179 loc) · 53 KB
/
saml_sp.js
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/*
* JavaScript functions for providing SAML SP with NGINX Plus
*
* Copyright (C) 2023 Nginx, Inc.
*/
export default {
handleSingleSignOn, // Process SAML Response form IdP
handleSingleLogout, // Process SAML LogoutRequest and LogoutResponse from IdP
handleAllMessages, // Process all SAML messages from IdP
initiateSingleSignOn, // Initiate SAML SSO by redirecting to IdP
initiateSingleLogout // Initiate SAML SLO by redirecting to IdP
};
const xml = require("xml");
const zlib = require("zlib");
const querystring = require("querystring");
const fs = require("fs");
const initiateSingleSignOn = produceSAMLMessage.bind(null, "AuthnRequest");
const initiateSingleLogout = produceSAMLMessage.bind(null, "LogoutRequest");
const handleSingleSignOn = handleSAMLMessage.bind(null, ["Response"]);
const handleSingleLogout = handleSAMLMessage.bind(null, ["LogoutRequest", "LogoutResponse"]);
const handleAllMessages = handleSAMLMessage.bind(null, ["Response", "LogoutRequest", "LogoutResponse"]);
/**
* Processing incoming SAML messages (Response, LogoutResponse, LogoutRequest).
* @param {Array} messageType - Array of expected SAML message types.
* @param {object} r - The request object.
*/
async function handleSAMLMessage(messageType, r) {
let id;
try {
let nameID, node;
/* Extract SAML parameters from the HTTP request */
const params = extractSAMLParameters(r);
/* Parse the SAML message for an XML document */
let root = xml.parse(params.SAMLResponse).$root;
/* Check the message type and validate the configuration */
messageType = checkSAMLMessageType(root, messageType);
const opt = parseConfigurationOptions(r, messageType);
/* Process the message header and verify the issuer */
id = processSAMLMessageHeader(r, opt, root);
checkIssuer(root.Issuer, opt.idpEntityID);
/* Verify the SAML signature if required */
opt.wantSignedResponse && await verifySAMLSignature(root, opt.verifyKeys);
/* Check for SAML replay attacks */
checkReplayAttack(r, id, messageType);
/* Handle different SAML message types */
switch (messageType) {
case 'Response':
/* Verify the SAML Response status */
verifyResponseStatus(root.Status);
/* Decrypt the Encrypted Assertion if present */
if (root.EncryptedAssertion) {
root = await decryptSAML(root.EncryptedAssertion, opt.decryptKey);
}
/* Process the Assertion header and verify the issuer */
opt.assertionId = processSAMLMessageHeader(r, opt, root.Assertion);
checkIssuer(root.Assertion.Issuer, opt.idpEntityID);
/* Verify the SAML Assertion signature if required */
opt.wantSignedAssertion && await verifySAMLSignature(root.Assertion, opt.verifyKeys);
/* Exctract NameID, NameIDFormat and check the SubjectConfirmation if present */
node = root.Assertion.Subject.NameID ? root.Assertion.Subject.NameID
: root.Assertion.Subject.EncryptedID || null;
nameID = await extractNameID(node, opt.decryptKey);
checkSubjectConfirmation(root.Assertion.Subject.SubjectConfirmation,
opt.allowedClockSkew);
/* Parse the Asserttion Conditions and Authentication Statement */
checkConditions(root.Assertion.Conditions, opt.spEntityID, opt.allowedClockSkew);
const authnStatement = parseAuthnStatement(root.Assertion.AuthnStatement, null,
opt.allowedClockSkew);
/* Set session cookie and save SAML variables and attributes */
const sessionCookie = setSessionCookie(r);
saveSAMLVariables(r, nameID, authnStatement);
saveSAMLAttributes(r, root.Assertion.AttributeStatement);
/* Redirect the user after successful login */
postLoginRedirect(r, params.RelayState || opt.relayState);
r.variables.saml_access_granted = '1';
r.log("SAML SP success, creating session " + sessionCookie);
return;
case 'LogoutRequest':
/* Exctract NameID and NameIDFormat */
node = root.NameID ? root.NameID : root.EncryptedID || null;
nameID = await extractNameID(node, opt.decryptKey);
/* Define necessary parameters needed to create a SAML LogoutResponse */
opt.nameID = nameID[0];
opt.inResponseTo = id;
opt.relayState = params.RelayState;
/* Rewrite the LogoutResponse URL if configured */
opt.idpServiceURL = opt.logoutResponseURL || opt.idpServiceURL;
/* Issue a SAML LogoutResponse */
await produceSAMLMessage('LogoutResponse', r, opt);
return;
case 'LogoutResponse':
/* Verify the SAML LogoutResponse status */
verifyResponseStatus(root.Status);
/* Clear the session cookie and redirect the user */
clearSession(r);
postLogoutRedirect(r, params.RelayState);
return;
}
} catch (e) {
samlError(r, 500, id, e);
}
}
function samlError(r, http_code, id, e) {
let msg = r.variables.saml_debug ? e.stack : "ReferenceError: " + e.message;
r.error(`SAML SSO Error: ReferenceID: ${id} ${msg}`);
r.variables.internal_error_message += `ReferenceID: ${id}`;
r.variables.internal_error_details = msg;
r.return(http_code);
}
/**
* Processes the SAML message header, validating the required fields and checking optional
* fields, such as Destination, according to the SAML 2.0 Core specification:
* https://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf
*
* - ID attribute (Required, see section 1.3.4): A unique identifier for the SAML message.
* - InResponseTo attribute (Optional, see section 3.2.2 for SSO and 3.7.3.1 for SLO):
* Indicates that the SAML message is a response to a previous request.
* - IssueInstant attribute (Required, see section 1.3.4): The timestamp when the SAML message
* was issued.
* - Destination attribute (Optional, see section 3.2.2 for SSO and 3.7.3.1 for SLO):
* The intended recipient of the SAML message.
*
* @param {Object} r - The incoming request object.
* @param {Object} opt - An object containing the SP options, including the SP Service URL.
* @param {Object} root - The SAML root element containing the message header.
* @returns {string} - The SAML message ID attribute.
* @throws {Error} - If the SAML message header contains invalid or unsupported values.
*/
function processSAMLMessageHeader(r, opt, root) {
const type = root.$name;
/* Check XML namespace for SAML message (Required) */
const expectedNs = type === 'Assertion'
? 'urn:oasis:names:tc:SAML:2.0:assertion'
: 'urn:oasis:names:tc:SAML:2.0:protocol';
if (root.$ns !== expectedNs) {
throw Error(`Unsupported XML namespace: "${root.$ns}" for ${type}`);
}
/* Check SAML message version (Required) */
if (root.$attr$Version !== "2.0") {
throw Error (`Unsupported SAML Version: "${root.$attr$Version}"`);
}
/* Check the date and time when the SAML message was issued (Required) */
const issueInstant = root.$attr$IssueInstant;
if (!issueInstant) {
throw Error("IssueInstant attribute is missing in the SAML message");
}
const issueInstantDate = new Date(issueInstant);
checkTimeValidity(issueInstantDate, null, opt.allowedClockSkew);
/* Check SAML message ID (Required) */
const id = root.$attr$ID;
if (!id) {
throw Error (`ID attribute is missing in the ${type} element`);
}
const inResponseTo = root.$attr$InResponseTo;
if (inResponseTo) {
/* SP-initiated SSO or SLO */
r.variables.saml_request_id = inResponseTo;
if (r.variables.saml_request_redeemed != '1') {
throw Error (`InResponseTo attribute value "${inResponseTo}" ` +
`not found in key-value storage for ${type} message`);
}
}
/* Check Destination if present (Optional) */
const destination = root.$attr$Destination;
if (destination && destination !== opt.spServiceURL) {
throw Error (`The SAML Destination "${destination}" does not match ` +
`SP ACS URL "${opt.spServiceURL}"`);
}
return id;
}
/**
* Checks the Issuer element in the SAML message according to the SAML 2.0 Core specification:
* https://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf
*
* The Issuer element (section 2.2.5) contains the SAML authority's unique identifier.
* This function checks if the issuer in the SAML message matches the expected IdP EntityID.
*
* @param {Object} root - The SAML Issuer element.
* @param {string} idpEntityId - The expected IdP EntityID.
* @throws {Error} - If the Issuer in the SAML message does not match the expected IdP EntityID.
*/
function checkIssuer(root, idpEntityId) {
const issuer = root.$text;
if (issuer && issuer !== idpEntityId) {
throw Error (`Issuer "${issuer}" does not match IdP EntityID "${idpEntityId}"`);
}
}
/**
* Verifies the SAML response status.
*
* According to SAML 2.0 Core specification (section 3.2.2.2):
* https://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf
* The <StatusCode> element contains the primary status code indicating the
* success or failure of the corresponding request. The <StatusMessage> and
* <StatusDetail> elements provide additional information.
*
* @param {Object} root - A SAML status XMLDoc object returned by xml.parse().
* @throws {Error} - If the SAML status is not "Success".
*/
function verifyResponseStatus (root) {
if (!root) {
throw Error("The Status element is missing in the SAML response");
}
if (!root.StatusCode || !root.StatusCode.$attr$Value) {
throw Error("The StatusCode element is missing in the Status");
}
const statusCode = root.StatusCode.$attr$Value;
const success = "urn:oasis:names:tc:SAML:2.0:status:Success";
if (statusCode !== success) {
let message = "StatusCode: " + statusCode;
if (root.statusMessage) {
message += ", SatusMessage: " + root.statusMessage.$text;
}
if (root.statusDetail) {
message += ", StatusDetail: " + JSON.stringify(root.statusDetail);
}
throw Error(message);
}
}
/**
* Extracts the NameID value and format from the given SAML root element, optionally
* decrypting it if it's encrypted.
*
* @param {Object} root - The SAML root element containing the NameID or EncryptedID.
* @param {string} keyData - The private key to decrypt the EncryptedID, if present.
* @returns {Promise<[string, string]>} - A promise that resolves to a tuple containing the
* NameID value and format.
* @throws {Error} - If the NameID element is missing in the Subject.
*/
async function extractNameID(root, keyData) {
if (!root) {
throw Error("NameID element is missing in the Subject");
}
const isEncrypted = root.$name === 'EncryptedID';
if (isEncrypted) {
root = (await decryptSAML(root, keyData)).NameID;
}
return [root.$text, root.$attr$Format];
}
/**
* Checks the SubjectConfirmation element in the SAML response.
*
* According to SAML 2.0 Core specification (section 2.4.1.1 and 2.4.1.2):
* https://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf
* The <SubjectConfirmation> element is used to provide additional
* information required to confirm the subject. The most common method is
* "urn:oasis:names:tc:SAML:2.0:cm:bearer".
*
* @param {Object} root - A SAML SubjectConfirmation XMLDoc object returned by xml.parse().
* @param {number} [allowedClockSkew] - The allowed clock skew in seconds.
* @throws {Error} - If the SubjectConfirmationData is missing or the subject has expired.
*/
function checkSubjectConfirmation(root, allowedClockSkew) {
if (!root) {
return;
}
if (root.$attr$Method === "urn:oasis:names:tc:SAML:2.0:cm:bearer") {
root = root.SubjectConfirmationData;
if (!root) {
throw new Error('SubjectConfirmationData element is missing in the ' +
'SubjectConfirmation');
}
const notOnOrAfter = root.$attr$NotOnOrAfter ? new Date(root.$attr$NotOnOrAfter) : null;
checkTimeValidity(null, notOnOrAfter, allowedClockSkew);
}
}
/**
* Checks the Conditions element in the SAML Assertion.
*
* According to SAML 2.0 Core specification (section 2.5.1.1):
* https://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf
* The <Conditions> element is used to specify conditions that must be evaluated
* when assessing the validity of and/or evaluating an assertion.
*
* @param {Object} root - A SAML Conditions XMLDoc object returned by xml.parse().
* @param {string} spEntityId - The EntityID of the Service Provider (SP).
* @param {number} [allowedClockSkew] - The allowed clock skew in seconds.
* @throws {Error} - If Conditions element is missing or the assertion is not valid or expired.
* Also throws an error if the audience restriction is not satisfied.
*/
function checkConditions(root, spEntityId, allowedClockSkew) {
if (!root) {
throw Error("Conditions element is missing in the Assertion");
}
const notBefore = root.$attr$NotBefore ? new Date(root.$attr$NotBefore) : null;
const notOnOrAfter = root.$attr$NotOnOrAfter ? new Date(root.$attr$NotOnOrAfter) : null;
checkTimeValidity(notBefore, notOnOrAfter, allowedClockSkew);
/* Check the audience restriction */
if (root.AudienceRestriction && root.AudienceRestriction.Audience) {
let audience = root.AudienceRestriction.Audience.$text;
if (!Array.isArray(audience)) {
audience = [audience];
}
const spFound = audience.indexOf(spEntityId) !== -1;
if (!spFound) {
throw Error("The Assertion is not intended for this Service Provider. " +
`Expected audience: ${spEntityId}, received: ${audience}`);
}
}
}
/**
* Parses the AuthnStatement element in the SAML Assertion.
*
* According to SAML 2.0 Core specification (section 2.7.2):
* https://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf
* The <AuthnStatement> element describes the act of authentication performed
* on the principal by the identity provider (IdP).
*
* @param {Object} root - A SAML AuthnStatement XMLDoc object returned by xml.parse().
* @param {number} [maxAuthenticationAge] - The maximum age (in seconds) of the authentication
* statement. If provided, the function will check
* if the AuthnInstant is within the allowed age.
* @param {number} [allowedClockSkew] - The allowed clock skew in seconds.
* @throws {Error} - If AuthnInstant, SessionNotOnOrAfter, or AuthnContext elements are missing,
* invalid, or expired.
* @returns {Object} - An object with SessionIndex and AuthnContextClassRef properties.
*/
function parseAuthnStatement(root, maxAuthenticationAge, allowedClockSkew) {
/* AuthnStatement element is optional */
if (!root) {
return;
}
const authnInstant = root.$attr$AuthnInstant;
if (!authnInstant) {
throw Error("The AuthnInstant attribute is missing in the AuthnStatement");
}
/* Placeholder for future maxAuthenticationAge conf option */
if (maxAuthenticationAge) {
const authnInstantDate = new Date(authnInstant);
const now = new Date();
if (now.getTime() - authnInstantDate.getTime() > maxAuthenticationAge*1000) {
return false;
}
}
const sessionIndex = root.$attr$SessionIndex || null;
const sessionNotOnOrAfter = root.$attr$SessionNotOnOrAfter ?
new Date(root.$attr$SessionNotOnOrAfter) : null;
checkTimeValidity(null, sessionNotOnOrAfter, allowedClockSkew);
root = root.AuthnContext;
if (!root) {
throw Error('The AuthnContext element is missing in the AuthnStatement');
}
if (!root.AuthnContextClassRef) {
throw Error('The AuthnContextClassRef element is missing in the AuthnContext');
}
const authnContextClassRef = root.AuthnContextClassRef.$text;
return [sessionIndex, authnContextClassRef];
}
/**
* Checks if the current time is within the allowed time range specified by
* notBefore and notOnOrAfter.
*
* @param {Date} notBefore - The notBefore time.
* @param {Date} notOnOrAfter - The notOnOrAfter time.
* @param {number} [allowedClockSkew] - Allowed clock skew in seconds.
* @throws {Error} - If the current time is outside the allowed time range.
*/
function checkTimeValidity(notBefore, notOnOrAfter, allowedClockSkew) {
const now = new Date();
if (notBefore && notBefore > new Date(now.getTime() + allowedClockSkew * 1000)) {
throw Error(`The Assertion is not yet valid. Current time is ${now} ` +
`and NotBefore is ${notBefore}. ` +
`Allowed clock skew is ${allowedClockSkew} seconds.`);
}
if (notOnOrAfter && notOnOrAfter < new Date(now.getTime() - allowedClockSkew * 1000)) {
throw Error(`The Assertion has expired. Current time is ${now} ` +
`and NotOnOrAfter is ${notOnOrAfter}. ` +
`Allowed clock skew is ${allowedClockSkew} seconds.`);
}
}
function saveSAMLVariables(r, nameID, authnStatement) {
r.variables.saml_name_id = nameID[0];
r.variables.saml_name_id_format = nameID[1];
if (authnStatement) {
if (authnStatement[0]) {
try {
r.variables.saml_session_index = authnStatement[0];
} catch(e) {}
}
try {
r.variables.saml_authn_context_class_ref = authnStatement[1];
} catch(e) {}
}
}
/**
* Extracts attributes from a SAML attribute statement and returns them as an object.
*
* @param {Object} root - A SAML attribute statement XMLDoc object returned by xml.parse().
* @returns {Object} - An object containing the attributes, with the attribute names as keys and
* attribute values as arrays of values.
*/
function getAttributes(root) {
return root.reduce((a, v) => {
a[v.$attr$Name] = v.$tags$AttributeValue.reduce((a, v) => {
a.push(v.$text);
return a;
}, []);
return a;
}, {});
}
function saveSAMLAttributes(r, root) {
if (!root) {
return;
}
let attrs = getAttributes(root.$tags$Attribute);
for (var attributeName in attrs) {
if (attrs.hasOwnProperty(attributeName)) {
var attributeValue = attrs[attributeName];
/* If the attribute name is a URI, take only the last part after the last "/" */
if (attributeName.includes("http://") || attributeName.includes("https://")) {
attributeName = attributeName.substring(attributeName.lastIndexOf('/')+1);
}
/* Save attributeName and value to the key-value store */
try {
r.variables['saml_attrib_' + attributeName] = attributeValue;
} catch(e) {}
}
}
}
function extractSAMLParameters(r) {
try {
const payload = getPayload(r);
if (!payload) {
throw Error("Unsupported HTTP method");
}
return parsePayload(payload, r.method);
} catch (e) {
throw Error(`Failed to extract SAMLRequest or SAMLResponse parameter ` +
`from the ${r.method} request: ${e.message}`);
}
}
function getPayload(r) {
switch (r.method) {
case 'GET':
return r.variables.arg_SAMLResponse || r.variables.arg_SAMLRequest ? r.variables.args
: null;
case 'POST':
return r.headersIn['Content-Type'] === 'application/x-www-form-urlencoded'
&& r.requestText.length ? r.requestText : null;
default:
return null;
}
}
function parsePayload(payload, method) {
const params = querystring.parse(payload);
let samlResponse = Buffer.from(decodeURIComponent(params.SAMLResponse || params.SAMLRequest),
'base64');
let relayState = decodeURIComponent(params.RelayState || "")
if (method === "GET") {
samlResponse = zlib.inflateRawSync(samlResponse);
}
return {SAMLResponse: samlResponse, RelayState: relayState};
}
function checkSAMLMessageType(root, messageType) {
const type = root.$name;
if (!messageType.includes(type)) {
throw Error(`Unsupported SAML message type: "${messageType}"`);
}
return type;
}
/**
* Generates a random string ID with a specified length.
*
* @param {number} keyLength - Length of the generated ID. If it's less than 20,
* the default value of 20 will be used.
* @returns {string} - A randomly generated string ID in hexadecimal format.
*/
function generateID(keyLength) {
keyLength = keyLength > 20 ? keyLength : 20;
let buf = Buffer.alloc(keyLength);
return (crypto.getRandomValues(buf)).toString('hex');
}
function setSessionCookie(r) {
/* Generate cookie_auth_token */
const authToken = "_" + generateID();
/* Save cookie_auth_token to keyval to store SAML session data */
r.variables.cookie_auth_token = authToken;
/* Set cookie_auth_token in the cookie */
r.headersOut["Set-Cookie"] = `auth_token=${authToken}; ${r.variables.saml_cookie_flags}`;
return authToken;
}
/**
* Checks for potential replay attacks by verifying if a SAML message ID has already been used.
*
* According to SAML 2.0 Core specification (section 1.3.4):
* https://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf
* Replay attacks can be prevented by ensuring that each SAML message ID is unique and
* is not reused within a reasonable time frame.
*
* @param {Object} r - The request object.
* @param {string} id - The SAML message ID.
* @param {string} type - The SAML message type (e.g., 'Response' or 'LogoutResponse').
* @throws {Error} - If a replay attack is detected (the SAML message ID has already been used).
*/
function checkReplayAttack(r, id, type) {
r.variables.saml_response_id = id;
if (r.variables.saml_response_redeemed === '1') {
throw Error (`An attempt to reuse a ${type} ID was detected: ` +
`ID "${id}" has already been redeemed`);
}
r.variables.saml_response_redeemed = '1';
}
function postLoginRedirect(r, relayState) {
/* If RelayState is not set in the case of IDP-initiated SSO, redirect to the root */
relayState = relayState || r.variables.cookie_auth_redir || '/';
const redirectUrl = (r.variables.redirect_base || '') + relayState;
r.return(302, redirectUrl);
}
function postLogoutRedirect(r, relayState) {
let redirectUrl = r.variables.redirect_base || '';
redirectUrl += relayState;
r.return(302, redirectUrl);
}
function clearSession(r) {
r.log("SAML logout for " + r.variables.saml_name_id);
r.variables.saml_access_granted = "-";
r.variables.saml_name_id = "-";
const cookieFlags = r.variables.saml_cookie_flags;
const expired = 'Expires=Thu, 01 Jan 1970 00:00:00 GMT; ';
r.headersOut['Set-Cookie'] = [
"auth_token=; " + expired + cookieFlags,
"auth_redir=; " + expired + cookieFlags
];
}
/**
* Generates an outgoing SAML message based on the messageType parameter.
* @param {string} messageType - The type of the SAML message (AuthnRequest, LogoutRequest, or LogoutResponse).
* @param {object} r - The NGINX request object.
* @param {object} opt - Optional object containing configuration options.
* @returns {Promise<void>}
* @throws {Error} - If there is an issue processing the SAML request.
*/
async function produceSAMLMessage(messageType, r, opt) {
let id;
try {
/* Validate SAML message type */
validateMessageType(messageType);
/**
* Parse configuration options based on messageType. For the case of the LogoutResponse,
* we reuse the 'opt' object, since it defines by the LogoutRequest.
*/
opt = opt || parseConfigurationOptions(r, messageType);
/* Generate a unique ID for the SAML message */
id = "_" + generateID(20);
/* Handle messageType actions */
switch (messageType) {
case "AuthnRequest":
/* Save the original request uri to the "auth_redir" cookie */
setAuthRedirCookie(r);
break;
case "LogoutRequest":
/**
* Perform simple session termination if SAML SLO is disabled or if the
* session has already expired or not found.
*/
if (!opt.nameID || opt.isSLODisabled) {
clearSession(r)
postLogoutRedirect(r, opt.relayState);
return;
}
break;
case "LogoutResponse":
/* Obtain the status code for the LogoutResponse message */
opt.statusCode = getLogoutStatusCode(r.variables.saml_name_id, opt.nameID)
break;
}
/* Create the SAML message based on messageType */
const xmlDoc = await createSAMLMessage(opt, id, messageType);
/* Clear session if LogoutResponse StatusCode is Success */
(opt.statusCode === 'urn:oasis:names:tc:SAML:2.0:status:Success') && clearSession(r);
/* Determine whether the HTTP response should be sent via POST or GET and dispatch */
const isPost = opt.requestBinding === 'HTTP-POST';
const postParam = messageType === 'LogoutResponse' ? 'SAMLResponse' : 'SAMLRequest';
dispatchResponse(r, xmlDoc, opt.idpServiceURL, opt.relayState, postParam, isPost);
/* Set SAML request ID and redeemed flag */
r.variables.saml_request_id = id;
r.variables.saml_request_redeemed = "1";
} catch (e) {
samlError(r, 500, id, e);
}
}
/**
* Validates the messageType, ensuring that it is one of the allowed values.
* @param {string} messageType - The type of the SAML message.
* @throws {Error} - If the messageType is not one of the allowed values.
*/
function validateMessageType(messageType) {
const allowedMessageTypes = ['AuthnRequest', 'LogoutRequest', 'LogoutResponse'];
if (!allowedMessageTypes.includes(messageType)) {
throw new Error(`Invalid messageType: ${messageType}. ` +
`Allowed values are: ${allowedMessageTypes.join(', ')}`);
}
}
function setAuthRedirCookie(r) {
r.headersOut['Set-Cookie'] = [
"auth_redir=" + r.variables.request_uri + "; " + r.variables.saml_cookie_flags
];
}
function getLogoutStatusCode(sessionNameID, requestNameID) {
/* If no session exists, return Logout Success */
if (!sessionNameID || sessionNameID === '-') {
return 'urn:oasis:names:tc:SAML:2.0:status:Success';
}
/* If session exists, return Logout Success if NameID matches */
return requestNameID === sessionNameID
? 'urn:oasis:names:tc:SAML:2.0:status:Success'
: 'urn:oasis:names:tc:SAML:2.0:status:Requester';
}
async function createSAMLMessage(opt, id, messageType) {
const handlers = {
AuthnRequest: () => ({
assertionConsumerServiceURL: ` AssertionConsumerServiceURL="${opt.spServiceURL}"`,
protocolBinding: ' ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"',
forceAuthn: opt.forceAuthn ? ' ForceAuthn="true"' : null,
nameIDPolicy: `<samlp:NameIDPolicy Format="${opt.nameIDFormat}" AllowCreate="true"/>`,
}),
LogoutRequest: () => ({
nameID: `<saml:NameID>${opt.nameID}</saml:NameID>`,
}),
LogoutResponse: () => ({
inResponseTo: ` InResponseTo="${opt.inResponseTo}"`,
status: `<samlp:Status><samlp:StatusCode Value="${opt.statusCode}"/></samlp:Status>`,
}),
};
const handlerResult = handlers[messageType]();
const assertionConsumerServiceURL = handlerResult.assertionConsumerServiceURL || "";
const protocolBinding = handlerResult.protocolBinding || "";
const forceAuthn = handlerResult.forceAuthn || "";
const nameIDPolicy = handlerResult.nameIDPolicy || "";
const nameID = handlerResult.nameID || "";
const inResponseTo = handlerResult.inResponseTo || "";
const status = handlerResult.status || "";
let message =
`<samlp:${messageType}` +
' xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"' +
' xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"' +
' Version="2.0"' +
` ID="${id}"` +
` IssueInstant="${new Date().toISOString()}"` +
` Destination="${opt.idpServiceURL}"` +
inResponseTo +
assertionConsumerServiceURL +
protocolBinding +
forceAuthn +
'>' +
`<saml:Issuer>${opt.spEntityID}</saml:Issuer>` +
`${opt.isSigned ? samlSignatureTemplate(id) : ''}` +
nameID +
nameIDPolicy +
status +
`</samlp:${messageType}>`;
let root;
try {
root = (xml.parse(message)).$root;
} catch (e) {
throw Error(`Failed to create ${messageType} from XML template: ${e.message}`);
}
if (opt.isSigned) {
try {
const rootSignature = root.Signature;
await digestSAML(rootSignature, true);
await signatureSAML(rootSignature, opt.signKey, true);
} catch (e) {
throw Error(`Failed to sign ${messageType}: ${e.message}`);
}
}
return xml.serializeToString(root);
}
/**
* Generates a SAML signature XML template with the provided ID.
*
* @param {string} id - The ID to use as a reference within the signature template.
* @returns {string} - The SAML signature XML template with the specified ID.
*/
function samlSignatureTemplate(id) {
const signTemplate =
'<ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">' +
'<ds:SignedInfo>' +
'<ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />' +
'<ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256" />' +
`<ds:Reference URI="#${id}">` +
'<ds:Transforms>' +
'<ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />' +
'<ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />' +
'</ds:Transforms>' +
'<ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256" />' +
'<ds:DigestValue></ds:DigestValue>' +
'</ds:Reference>' +
'</ds:SignedInfo>' +
'<ds:SignatureValue></ds:SignatureValue>' +
'</ds:Signature>';
return signTemplate;
}
function postFormTemplate(samlMessage, idpServiceUrl, relayState, messageType ) {
relayState = relayState ? `<input type="hidden" name="RelayState" value="${relayState}" />` : "";
return `
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>NGINX SAML SSO</title>
</head>
<body>
<script>
window.onload = function() {
document.getElementById("submitButton").style.display = "none";
document.forms[0].submit();
};
</script>
<noscript>
<p><strong>Note:</strong>
Since your browser does not support JavaScript,
you must press the button below once to proceed.</p>
</noscript>
<form method="post" action="${idpServiceUrl}">
<input type="submit" id="submitButton"/>
<input type="hidden" name="${messageType}" value="${samlMessage}" />
${relayState}
<noscript>
<button type="submit" class="btn">Continue Login</button>
</noscript>
</form>
</body>
</html>`;
}
/**
* Dispatches a SAML response to the IdP service URL using either HTTP-POST or HTTP-Redirect binding.
*
* @param {object} r - The NJS HTTP request object.
* @param {string} root - The SAML response XML string.
* @param {string} idpServiceUrl - The IdP service URL where the response should be sent.
* @param {string} relayState - The RelayState parameter value to include with the response.
* @param {string} postParam - The name of the POST parameter to use for sending the encoded XML.
* @param {boolean} isPost - If true, use HTTP-POST binding; otherwise, use HTTP-Redirect binding.
* @returns {object} - The NJS HTTP response object with appropriate headers and content.
*/
function dispatchResponse(r, root, idpServiceUrl, relayState, postParam, isPost) {
let encodedXml;
// Set outgoing headers for the response
r.headersOut['Content-Type'] = "text/html";
if (isPost) {
// Encode the XML string as base64 for the HTTP-POST binding
encodedXml = Buffer.from(root).toString("base64");
// Return the response with the POST form template
return r.return(200, postFormTemplate(encodedXml, idpServiceUrl, relayState, postParam));
} else {
// Compress and encode the XML string as base64 for the HTTP-Redirect binding
const compressedXml = zlib.deflateRawSync(root);
encodedXml = Buffer.from(compressedXml).toString("base64");
// Construct the IdP service URL with the encoded XML and RelayState (if provided)
const url = `${idpServiceUrl}?${postParam}=${encodeURIComponent(encodedXml)}` +
`${relayState ? `&RelayState=${relayState}` : ""}`;
// Return the response with a 302 redirect to the constructed URL
return r.return(302, url);
}
}
/*
* verifySAMLSignature() implements a verify clause
* from Profiles for the OASIS SAML V2.0
* 4.1.4.3 <Response> Message Processing Rules
* Verify any signatures present on the assertion(s) or the response
*
* verification is done in accordance with
* Assertions and Protocols for the OASIS SAML V2.0
* 5.4 XML Signature Profile
*
* The following signature algorithms are supported:
* - http://www.w3.org/2001/04/xmldsig-more#rsa-sha256
* - http://www.w3.org/2000/09/xmldsig#rsa-sha1
*
* The following digest algorithms are supported:
* - http://www.w3.org/2000/09/xmldsig#sha1
* - http://www.w3.org/2001/04/xmlenc#sha256
*
* @param root an XMLDoc object returned by xml.parse().
* @param keyDataArray is array of SubjectPublicKeyInfo in PKCS#1 format.
*/
async function verifySAMLSignature(root, keyDataArray) {
const type = root.$name;
const rootSignature = root.Signature;
if (!rootSignature) {
throw Error(`Message is unsigned`);
}
const errors = [];
for (let i = 0; i < keyDataArray.length; i++) {
try {
const digestResult = await digestSAML(rootSignature);
const signatureResult = await signatureSAML(rootSignature, keyDataArray[i]);
if (digestResult && signatureResult) {
return;
} else {
errors.push(`Key index ${i}: signature verification failed`);
}
} catch (e) {
errors.push(e.message);
}
}
throw Error(`Error verifying ${type} message signature: ${errors.join(', ')}`);
}
async function digestSAML(signature, produce) {
const parent = signature.$parent;
const signedInfo = signature.SignedInfo;
const reference = signedInfo.Reference;
/* Sanity check. */
const URI = reference.$attr$URI;
const ID = parent.$attr$ID;
if (URI != `#${ID}`) {
throw Error(`signed reference URI ${URI} does not point to the parent ${ID}`);
}
/*
* Assertions and Protocols for the OASIS SAML V2.0
* 5.4.4 Transforms
*
* Signatures in SAML messages SHOULD NOT contain transforms other than
* the http://www.w3.org/2000/09/xmldsig#enveloped-signature and
* canonicalization transforms http://www.w3.org/2001/10/xml-exc-c14n# or
* http://www.w3.org/2001/10/xml-exc-c14n#WithComments.
*/
const transforms = reference.Transforms.$tags$Transform;
const transformAlgs = transforms.map(t => t.$attr$Algorithm);
if (transformAlgs[0] != 'http://www.w3.org/2000/09/xmldsig#enveloped-signature') {
throw Error(`unexpected digest transform ${transforms[0]}`);
}
if (!transformAlgs[1].startsWith('http://www.w3.org/2001/10/xml-exc-c14n#')) {
throw Error(`unexpected digest transform ${transforms[1]}`);
}
const namespaces = transformAlgs[1].InclusiveNamespaces;
const prefixList = namespaces ? namespaces.$attr$PrefixList: null;
const withComments = transformAlgs[1].slice(39) == 'WithComments';
let hash;
const alg = reference.DigestMethod.$attr$Algorithm;
switch (alg) {
case "http://www.w3.org/2000/09/xmldsig#sha1":
hash = "SHA-1";
break;
case "http://www.w3.org/2001/04/xmlenc#sha256":
hash = "SHA-256";
break;
default:
throw Error(`unexpected digest Algorithm ${alg}`);
}
const c14n = xml.exclusiveC14n(parent, signature, withComments, prefixList);
const dgst = await crypto.subtle.digest(hash, c14n);
const b64dgst = Buffer.from(dgst).toString('base64');
if (produce) {
signedInfo.Reference.DigestValue.$text = b64dgst;
return b64dgst;
}
const expectedDigest = signedInfo.Reference.DigestValue.$text;
return expectedDigest === b64dgst;
}
function keyPem2Der(pem, type) {
const pemJoined = pem.toString().split('\n').join('');
const pemHeader = `-----BEGIN ${type} KEY-----`;
const pemFooter = `-----END ${type} KEY-----`;
const pemContents = pemJoined.substring(pemHeader.length, pemJoined.length - pemFooter.length);