A PDF that needs a signature, a highlight or a page removed currently sends
the user out to a desktop application or, worse, to a web service that wants
the document uploaded first. Both are poor answers for a browser whose point
is that nothing has to leave the machine. This is a full-tab editor that opens
a PDF, marks it up, fills its forms and saves a new copy, entirely locally.
Two engines, vendored rather than installed, because an add-on ships as a
self-contained folder over the signed update channel and nothing runs a
package manager on the way: pdf.js reads and renders, pdf-lib writes. They
share no state. Everything in between lives in PDF user space — points,
origin bottom-left — which is the one coordinate vocabulary both speak, so a
mark survives zooming, rotating and reordering with no conversion table and
save-time needs to know nothing about how a page happened to be displayed.
The page strip is built from pdf.js's PDFPageView components rather than its
PDFViewer, which renders pages in the file's own order and cannot hide,
reorder or individually rotate one — three of the features here. Text layers
are ours and stay attached for every page, drawn or not, because Theseus's
find bar is Chromium's findInPage over the live DOM and a torn-down text layer
is a page Ctrl+F cannot see. Canvases are virtualised; a letter page at 100%
is 3.4 MB of bitmap.
Redaction is the part worth being careful about. A black box over text hides
nothing — the text stays in the content stream and comes straight out of a
copy-paste — so the editor says so in a modal before the tool can be used,
and on save rebuilds each redacted page as an image, which genuinely removes
it. Pages that were not redacted are untouched. Form widgets and links are
kept, since they were never the leak.
Saving never writes over the original: every save reloads the source bytes and
replays the session onto a fresh copy, so a botched save cannot poison the
next one.
Out of scope for this first version: editing the text that is already in the
document, and writing XFA forms back (pdf-lib cannot, so those are fill-and-
print only, and the editor says so on open).
The publishing steps pointed at scp to /opt/silent-mode/site/addons/, which
never existed; the screenshot channel (and now aegis) is served from
s3://bns/theseus/extensions/<id>/ through navigate.st/bns/theseus.x/….
Also: sign from a git-archive copy so uncommitted edits don't ship.
Decouples bundled-add-on updates from Theseus releases. An add-on
whose addon.json declares an updateURL can be republished at any time
without shipping a new Theseus installer; existing installs pick it up
on the next boot's +30 s background check.
Client flow (main-process only, no UI touchpoints in this commit):
initAddons()
├── promoteStagedUpdates() # promote signed stage if newer
├── seedBundledAddons() # bundle wins over on-disk if newer
└── AddonHost.discoverAndActivate()
30 s later:
└── checkAndStageUpdates() # fetch, verify, download, stage
Signature: Ed25519 over
"silentmode.addon-update-v1|<id>|<version>|<tarball-sha256>",
verified against a hardcoded set of operator pubkeys living in
addon-update-pubkeys.js. Domain-separated so the operator key can't
be tricked into signing a message with a different purpose. Empty
pubkey array is the shipping default — checkAndStageUpdates() then
short-circuits and no outbound requests are made, which is the safe
posture until the operator ceremonies a key in.
Payload: gzipped tar, extracted with the system tar (present on
Win10 1803+, macOS, Linux). Path traversal defended by tar's default
refusal of `..` entries; the extracted manifest's id + version are
re-checked against the signed values before staging.
Staged updates go to <userData>/addons-updates-staged/<id>-<version>/.
Promotion into <userData>/addons/<id>/ reuses seedBundledAddons's
backup dance: existing folder moves to
<userData>/addons-backups/<id>-<oldver>-<timestamp>/ so any local
edits survive.
New files:
- addon-updater.js — client
- addon-update-pubkeys.js — hardcoded pubkeys (empty; edit + rebuild to rotate)
- scripts/generate-update-keypair.mjs — one-time keygen
- scripts/sign-addon-update.mjs — operator packager+signer
- docs/ADDON-UPDATES.md — operator brief + threat model
Wired into main.js at boot; screenshot add-on's addon.json advertises
the reference updateURL for when the endpoint goes live.
