8.8 KiB
logsdu
A Firefox extension for logins that password managers cannot save: the ones made of a registration number, a date of birth and a document number, instead of a username and a password.
Academic portals do this a lot. The form is usually marked autocomplete="off",
none of the fields is a password field, and Bitwarden, Firefox and Chrome all
decline to remember it. When the values never change and the institution offers
no other way in, the only option left is copying three values by hand, every
single time -- including the registration number nobody has memorised.
logsdu stores them once and fills them in. By default it also presses the submit button, so the normal case is zero clicks.
Install
Once it is published, from addons.mozilla.org. Until then, build it yourself:
corepack pnpm install # first time, or after a dependency change
make xpi # typecheck, bundle, and package logsdu-<version>.xpi
make xpi prints the full path of the file and how to install it. The package
it produces is unsigned, and Firefox only accepts unsigned add-ons on the ESR,
Developer Edition and Nightly builds, after setting
xpinstall.signatures.required to false in about:config. On release Firefox
the file has to be signed by Mozilla first -- see "Publishing".
Dependencies are managed with pnpm, never npm. See "Why pnpm" below.
Setting it up
Open the extension's options page and fill in four values:
| Field | Example | Notes |
|---|---|---|
| Portal address | https://portal.example.br/ |
Only the origin matters; the path is ignored |
| Registration number | 2000101010 |
Digits only |
| Date of birth | 01/01/2000 |
Reformatted as you type |
| Document number | 000.000.000-00 |
Reformatted as you type |
Paste raw digits if you like -- the options page inserts the separators, because input masks on these forms expect the values in exactly that shape.
When you press Save, Firefox asks whether logsdu may access the address you entered. That prompt names one site. Accept it and the extension starts working there; decline and nothing is stored as usable.
If the portal's markup differs from the common shape, open Ajustes avançados in the options page and adjust the CSS selectors. Invalid selectors are rejected on save rather than failing silently later.
What it can access
Nothing, until you say so.
The manifest requests no host permissions at all. There is no content script
declared against any site. When you save an address, the extension asks for that
single origin through permissions.request(), and a background script then
registers the content script for that one origin and no other.
That means a fresh install can read no pages, the permission prompt names one
site, and you can revoke it whenever you like in about:addons -> Permissions.
Clearing your data in the options page hands the permission back automatically.
The optional_host_permissions entry in the manifest is *://*/*, because the
address is not known until you type it. It is the set the extension may ask
from, not what it holds -- nothing is granted without your click, and what is
granted is one origin.
How it behaves
- Fills and submits on the login page, with no interaction.
- At most one automatic submit per hour. After an attempt it drops back to filling only, so a wrong value cannot resubmit itself on every page load and lock you out of your account. Correct the values and save; saving clears the timer, so the next visit tries again immediately.
- Logging out keeps you logged out. Clicking the portal's logout control suppresses the automatic submit for five minutes -- otherwise the logout redirect lands on the login page and you would be signed straight back in.
- When it fills without submitting, a small note at the bottom of the page says why. Click it to dismiss.
- The toolbar popup has a Preencher agora button that fills without submitting, for when you want to check the values before sending them.
- Automatic submission can be turned off entirely in the options.
Where your data goes
Nowhere. It is written to storage.local: private to your browser profile,
never synced, never transmitted. The extension makes no network requests of its
own and contains no analytics.
Be clear about the limit, though. This is the same protection a browser-saved password gets, and it has the same weakness -- anyone with your unlocked computer can read it. If you need protection at rest, this is the wrong tool.
The interface is in Portuguese, matching the portals it was written for.
Publishing
make xpi produces the file to upload at
addons.mozilla.org.
Two distribution choices:
- Listed -- public on addons.mozilla.org, searchable, installable by anyone, and updates are delivered by Mozilla automatically.
- Unlisted -- signed but not published. You distribute the signed file yourself. Updates need a self-hosted update manifest, or resending the file.
Builds are never minified, which is deliberate: AMO requires a separate source-code submission for any add-on whose uploaded code is machine-generated, and that obligation would apply to every future release. The whole extension is about 33 KB, so the saving would not pay for the process, and readable code is easier for a reviewer -- or anyone auditing what handles their credentials -- to check.
Chrome
make chrome builds it. The only difference is the background key: Firefox MV3
uses an event page, Chrome MV3 requires a service worker, so the manifest is
generated per target rather than duplicated. Everything else -- chrome.*
namespace, MV3, no Firefox-only APIs -- is already shared.
It has not been tested against Chrome. Do not assume it works.
Development
corepack pnpm install
make test # unit tests
make # typecheck and bundle into build/
corepack pnpm run dev # rebuild on change
make clean
While iterating, load the unpacked directory rather than reinstalling an .xpi
each time: about:debugging -> This Firefox -> Load Temporary Add-on ->
build/manifest.json, then press Reload there after each rebuild. That copy
disappears on restart, which is the point -- it is for development, not daily
use.
corepack pnpm run dev watches and rebuilds, static files included, but Firefox
still needs the Reload click to pick anything up.
Layout
| Path | Role |
|---|---|
src/manifest.json |
MV3 manifest. Requests no host access |
src/background.ts |
Registers the content script for the granted origin |
src/content.ts |
Isolated world. Decides whether to act, then delegates |
src/injected.ts |
Page world. Does the actual filling and clicking |
src/portal.ts |
Default selectors and the shape of a fill request |
src/config.ts |
Stored values, the rate limit and the logout cooldown |
src/format.ts |
Input normalisers for the three masked fields |
src/options.*, src/popup.* |
The two bits of UI |
Why two scripts instead of one
These portals drive their inputs with Inputmask, which replaces each element's
value property with its own accessor. A content script assigning input.value
from the isolated world writes through Xrays to the native setter and skips
that accessor: the field looks right on screen, but the mask's buffer is
unchanged, and the page's submit handler reads the stale buffer back out through
jQuery. So the filling happens inside the page, through the page's own jQuery
and Inputmask, in injected.ts.
Submitting is a real click on the button, never form.submit(). These portals
intercept the submit event, cancel it, and post by AJAX with a CSRF token taken
from a meta tag. form.submit() would bypass that handler and lose the token; a
click reproduces exactly what a person pressing the button does.
Why the field selectors are configurable
Hardcoding them would tie the extension to one institution while pretending to
be general. They live in portal.ts as defaults and can be overridden per
installation, so the same build works for any portal of this shape -- and no
institution is named anywhere in the source, the manifest or the build output.
Why pnpm, not npm
Do not run npm install or npm ci in this repo. This project is developed
on ZFS, and npm's installer renames many directories in parallel while
hoisting and deduping, which ZFS intermittently fails with:
npm error code ENOTEMPTY
npm error syscall rename
pnpm hard-links packages from a global content-addressable store and does not
perform that rename dance, so it is unaffected. Only npm install / npm ci
are the problem -- running scripts through npm is fine, since that just spawns
tsc and esbuild. The lockfile is pnpm-lock.yaml; there is no
package-lock.json and none should be created.
Licence
GPL-3.0-or-later. See LICENSE.