Information leak: Last visit redirect is triggered also for anonymous requests (public home page, if shared document)

[almereyda]

When an anonymous user visits an instance, they are redirected to the last visited page.

• If that is a publicly shared page, they are stuck there.
  It is still possible to manually call the /login route for creating a valid session through logging in.
• If it is a private page, they are redirected and asked to /login.

It would be expected that knowledge of the last_visit state is restricted to logged in users only, and not leaked to the public.

---

This runtime value is mutated when a logged in user does call loadNoteById:

notea/components/container/edit-container.tsx

Line 31 in d5f8113

const loadNoteById = useCallback(

And is set to the id for all cases, in which no new ID is opened:

notea/components/container/edit-container.tsx

Lines 71 to 75 in d5f8113

	if (!isNew && id !== 'new') {
	await mutateSettings({
	last_visit: `/${id}`,
	});
	}

---

This also allows to set a temporary home page of a Notea instance, by carefully choosing the page last navigated to in a Notea tab before closing it.

---

Further down the road, somehow a similar "feature", combining a targeted redirect and a publicly shared page, could allow for a nice and simple "home page" of an instance. This would seemingly require an additional (runtime) setting, such as last_visit, but set and named differently.

---

Remediation would probably center around these pieces of the code base, where the lastVisit is patched into the request, if a user isLoggedIn:

notea/pages/index.tsx

Lines 57 to 66 in d5f8113

	const lastVisit = ctx.req.props?.settings?.last_visit;
	if (lastVisit && ctx.req.session.get('user')?.isLoggedIn) {
	return {
	redirect: {
	destination: lastVisit,
	permanent: false,
	},
	};
	}

This is always true, if the auth.type equals to none.

notea/libs/server/middlewares/auth.ts

Lines 23 to 25 in d5f8113

	if (cfg.auth.type === 'none') {
	return true;
	}

Which always seems to be the case:

notea/libs/server/config.ts

Line 143 in d5f8113

let auth: AuthConfiguration = { type: 'none' };

[almereyda]

I'm also not perfectly sure how this line is to be read:

notea/libs/server/config.ts

Line 28 in d5f8113

export type AuthConfiguration = { type: 'none' } | BasicAuthConfiguration;

And how it is to be interpreted in the context of the type exports just before:

notea/libs/server/config.ts

Lines 15 to 27 in d5f8113

	export type BasicUser = { username: string; password: string };
	type BasicMultiUserConfiguration = {
	username?: never;
	password?: never;
	users: BasicUser[];
	};
	type BasicSingleUserConfiguration = { username?: string; password: string } & {
	users?: never;
	};
	export type BasicAuthConfiguration = { type: 'basic' } & (
	| BasicSingleUserConfiguration
	| BasicMultiUserConfiguration
	);

#108 states that Notea is distinctively a single user platform. Why would it declare and export any MultiUser type?

[almereyda]

This is an edge case, which I have only found, because I had last visited a publicly shared page.

It's possible to reproduce this behaviour with an unauthenticated curl client:

$ curl -I https://notea.example.org 2>/dev/null | grep '307|location'
HTTP/2 307 
location: /U0lXWiHywE

[tecc]

This is actually a non-issue, at least in the latest alpha version. The issue was glanced upon in #169, which I promptly fixed.

The multiple-user configuration stuff is a remnant from when I was going to add that feature - this was when I was working on it as a fork, rather than as the maintainer. Things happened, I became the maintainer (although I've been doing an awful job thus far), and I decided to merge my changes to the upstream.

[almereyda]

Thanks for fixing this already.

Yes, #169 (comment) describes the same issue, I agree.