FoundKey/packages/backend/src/server/api/common/oauth.ts

130 lines
3.1 KiB
TypeScript

import * as crypto from 'node:crypto';
import Koa from 'koa';
import { IsNull, Not } from 'typeorm';
import { Apps, AuthSessions } from '@/models/index.js';
import { compareUrl } from './compare-url.js';
export async function oauth(ctx: Koa.Context): void {
const {
grant_type,
code,
redirect_uri,
code_verifier,
} = ctx.request.body;
// check if any of the parameters are null or empty string
if ([grant_type, code].some(x => !x)) {
ctx.response.status = 400;
ctx.response.body = {
error: 'invalid_request',
};
return;
}
if (grant_type !== 'authorization_code') {
ctx.response.status = 400;
ctx.response.body = {
error: 'unsupported_grant_type',
error_description: 'only authorization_code grants are supported',
};
return;
}
const authHeader = ctx.headers.authorization;
if (!authHeader?.toLowerCase().startsWith('basic ')) {
ctx.response.status = 401;
ctx.response.set('WWW-Authenticate', 'Basic');
ctx.response.body = {
error: 'invalid_client',
error_description: 'HTTP Basic Authentication required',
};
return;
}
const [client_id, client_secret] = new Buffer(authHeader.slice(6), 'base64')
.toString('ascii')
.split(':', 2);
const [app, session] = await Promise.all([
Apps.findOneBy({
id: client_id,
secret: client_secret,
}),
AuthSessions.findOne({
where: {
appId: client_id,
token: code,
// only check for approved auth sessions
accessTokenId: Not(IsNull()),
},
relations: {
accessToken: true,
},
}),
]);
if (app == null) {
ctx.response.status = 401;
ctx.response.set('WWW-Authenticate', 'Basic');
ctx.response.body = {
error: 'invalid_client',
error_description: 'authentication failed',
};
return;
}
if (session == null) {
ctx.response.status = 400;
ctx.response.body = {
error: 'invalid_grant',
};
return;
}
// check PKCE challenge, if provided before
if (session.pkceChallenge) {
// Also checking the client's homework, the RFC says:
//> minimum length of 43 characters and a maximum length of 128 characters
if (!code_verifier || code_verifier.length < 43 || code_verifier.length > 128) {
ctx.response.status = 400;
ctx.response.body = {
error: 'invalid_grant',
error_description: 'invalid or missing PKCE code_verifier',
};
return;
} else {
// verify that (from RFC 7636):
//> BASE64URL-ENCODE(SHA256(ASCII(code_verifier))) == code_challenge
const hash = crypto.createHash('sha256');
hash.update(code_verifier);
if (hash.digest('base64url') !== code_challenge) {
ctx.response.status = 400;
ctx.response.body = {
error: 'invalid_grant',
error_description: 'invalid PKCE code_verifier',
};
return;
}
}
}
// check redirect URI
if (!compareUrl(app.callbackUrl, redirect_uri)) {
ctx.response.status = 400;
ctx.response.body = {
error: 'invalid_grant',
error_description: 'Mismatched redirect_uri',
};
return;
}
// session is single use
await AuthSessions.delete(session.id),
ctx.response.status = 200;
ctx.response.body = {
access_token: session.accessToken.token,
token_type: 'bearer',
scope: session.accessToken.permission.join(' '),
};
}