documenso/packages/lib/server-only/document/is-recipient-authorized.ts

import { verifyAuthenticationResponse } from '@simplewebauthn/server';
import { match } from 'ts-pattern';

import { prisma } from '@documenso/prisma';
import type { Document, Recipient } from '@documenso/prisma/client';

import { verifyTwoFactorAuthenticationToken } from '../2fa/verify-2fa-token';
import { AppError, AppErrorCode } from '../../errors/app-error';
import type { TDocumentAuth, TDocumentAuthMethods } from '../../types/document-auth';
import { DocumentAuth } from '../../types/document-auth';
import type { TAuthenticationResponseJSONSchema } from '../../types/webauthn';
import { getAuthenticatorOptions } from '../../utils/authenticator';
import { extractDocumentAuthMethods } from '../../utils/document-auth';

type IsRecipientAuthorizedOptions = {
  type: 'ACCESS' | 'ACTION';
  document: Document;
  recipient: Recipient;

  /**
   * The ID of the user who initiated the request.
   */
  userId?: number;

  /**
   * The auth details to check.
   *
   * Optional because there are scenarios where no auth options are required such as
   * using the user ID.
   */
  authOptions?: TDocumentAuthMethods;
};

const getRecipient = async (email: string) => {
  return await prisma.user.findFirst({
    where: {
      email,
    },
    select: {
      id: true,
    },
  });
};

/**
 * Whether the recipient is authorized to perform the requested operation on a
 * document, given the provided auth options.
 *
 * @returns True if the recipient can perform the requested operation.
 */
export const isRecipientAuthorized = async ({
  type,
  document,
  recipient,
  userId,
  authOptions,
}: IsRecipientAuthorizedOptions): Promise<boolean> => {
  const { derivedRecipientAccessAuth, derivedRecipientActionAuth } = extractDocumentAuthMethods({
    documentAuth: document.authOptions,
    recipientAuth: recipient.authOptions,
  });

  const authMethod: TDocumentAuth | null =
    type === 'ACCESS' ? derivedRecipientAccessAuth : derivedRecipientActionAuth;

  // Early true return when auth is not required.
  if (!authMethod || authMethod === DocumentAuth.EXPLICIT_NONE) {
    return true;
  }

  // Create auth options when none are passed for account.
  if (!authOptions && authMethod === DocumentAuth.ACCOUNT) {
    authOptions = {
      type: DocumentAuth.ACCOUNT,
    };
  }

  // Authentication required does not match provided method.
  if (!authOptions || authOptions.type !== authMethod) {
    return false;
  }

  return await match(authOptions)
    .with({ type: DocumentAuth.ACCOUNT }, async () => {
      if (userId === undefined) {
        return false;
      }

      const recipientUser = await getRecipient(recipient.email);

      if (!recipientUser) {
        return false;
      }

      return recipientUser.id === userId;
    })
    .with({ type: DocumentAuth.PASSKEY }, async ({ authenticationResponse, tokenReference }) => {
      if (!userId) {
        return false;
      }

      return await isPasskeyAuthValid({
        userId,
        authenticationResponse,
        tokenReference,
      });
    })
    .with({ type: DocumentAuth['2FA'] }, async ({ token }) => {
      if (!userId) {
        return false;
      }

      const user = await prisma.user.findFirst({
        where: {
          id: userId,
        },
      });

      // Should not be possible.
      if (!user) {
        throw new AppError(AppErrorCode.NOT_FOUND, 'User not found');
      }

      return await verifyTwoFactorAuthenticationToken({
        user,
        totpCode: token,
      });
    })
    .exhaustive();
};

type VerifyPasskeyOptions = {
  /**
   * The ID of the user who initiated the request.
   */
  userId: number;

  /**
   * The secondary ID of the verification token.
   */
  tokenReference: string;

  /**
   * The response from the passkey authenticator.
   */
  authenticationResponse: TAuthenticationResponseJSONSchema;

  /**
   * Whether to throw errors when the user fails verification instead of returning
   * false.
   */
  throwError?: boolean;
};

/**
 * Whether the provided passkey authenticator response is valid and the user is
 * authenticated.
 */
const isPasskeyAuthValid = async (options: VerifyPasskeyOptions): Promise<boolean> => {
  return verifyPasskey(options)
    .then(() => true)
    .catch(() => false);
};

/**
 * Verifies whether the provided passkey authenticator is valid and the user is
 * authenticated.
 *
 * Will throw an error if the user should not be authenticated.
 */
const verifyPasskey = async ({
  userId,
  tokenReference,
  authenticationResponse,
}: VerifyPasskeyOptions): Promise<void> => {
  const passkey = await prisma.passkey.findFirst({
    where: {
      credentialId: Buffer.from(authenticationResponse.id, 'base64'),
      userId,
    },
  });

  const verificationToken = await prisma.verificationToken
    .delete({
      where: {
        userId,
        secondaryId: tokenReference,
      },
    })
    .catch(() => null);

  if (!passkey) {
    throw new AppError(AppErrorCode.NOT_FOUND, 'Passkey not found');
  }

  if (!verificationToken) {
    throw new AppError(AppErrorCode.NOT_FOUND, 'Token not found');
  }

  if (verificationToken.expires < new Date()) {
    throw new AppError(AppErrorCode.EXPIRED_CODE, 'Token expired');
  }

  const { rpId, origin } = getAuthenticatorOptions();

  const verification = await verifyAuthenticationResponse({
    response: authenticationResponse,
    expectedChallenge: verificationToken.token,
    expectedOrigin: origin,
    expectedRPID: rpId,
    authenticator: {
      credentialID: new Uint8Array(Array.from(passkey.credentialId)),
      credentialPublicKey: new Uint8Array(passkey.credentialPublicKey),
      counter: Number(passkey.counter),
    },
  }).catch(() => null); // May want to log this for insights.

  if (verification?.verified !== true) {
    throw new AppError(AppErrorCode.UNAUTHORIZED, 'User is not authorized');
  }

  await prisma.passkey.update({
    where: {
      id: passkey.id,
    },
    data: {
      lastUsedAt: new Date(),
      counter: verification.authenticationInfo.newCounter,
    },
  });
};