Files
DodoSSH/docs/adr/0014-android-updates.md
T
jaap-jan ca7fee2358 Start the confirmation Android hands back, so an update can install
Pressing INSTALL closed the application, installed nothing and said nothing. That
is two independent faults in one method, either of which breaks it on its own,
and they hid each other: the first kills the process before the second can be
observed, and the second is silent by construction.

The pending intent handed to commit was implicit — an action string with no
component behind it. A mutable pending intent may not wrap one of those from API
34, and this head targets 36, so every current phone threw IllegalArgumentException
before commit was reached. Nothing caught it, so it left the command handler,
passed the dispatcher and took the process with it. That is the closing.

Below 34, where it did not throw, it still installed nothing. An application
holding REQUEST_INSTALL_PACKAGES rather than the privileged INSTALL_PACKAGES gets
no verdict back from a commit: what the platform answers first is
STATUS_PENDING_USER_ACTION, carrying the activity that draws the dialogue in
EXTRA_INTENT for the application to start. Android does not draw it on its own.
The comment here asserted the opposite — that a pending intent is required whether
or not anything listens, and that nothing needed to — so no receiver was ever
written, and the session was written, committed and left staged forever.

So there is a receiver now, not exported because the only sender is this
application's own commit, and the intent naming it is explicit, which is the same
change that stops the throw. Sessions are abandoned when anything fails, since one
created and neither committed nor abandoned stays staged against a per-application
cap — a repeating fault would have started failing at CreateSession instead, which
is the same bug wearing a completely unrelated face.

The reporting is the part worth keeping even after the cause is gone. Where
applying ends the process an exception has nowhere to go; where it does not, which
is this head's whole shape, it goes out through the dispatcher. RestartNowAsync now
answers the way CheckNowAsync already did, and the regression test asserts the
absence of a throw rather than the presence of one.

ADR 0014 rule 6 gets the correction in place: "asks Android to ask" is one step
longer than it reads. Check 17.5 needed no rewording — it asks for the installer
appearing by name, which is exactly the thing that never happened — so what it
gets instead is the two symptoms named, because both present as a dead button. It
is the only thing in the project that can catch either, and it plainly was never
run against a real pair of builds.

Note for whoever takes the next nightly: a broken updater cannot install its own
fix. The phone is running the code this commit replaces, so the first build
carrying it has to be sideloaded by hand; the ones after that install normally.

Compile-verified and manifest-verified — the receiver reaches the generated
manifest — and 321 tests pass. Not run on a device, which is what 17.5 is for.
2026-08-05 22:31:33 +02:00

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Markdown

# ADR 0014 — Updating the Android client, and the two channels that makes necessary
- Status: accepted
- Date: 2026-08-04
- Builds on: [ADR 0011](0011-android-distribution.md), [ADR 0013](0013-desktop-distribution-and-updates.md)
- Amends: ADR 0011's consequence that there is "no automatic update"
## Context
[ADR 0011](0011-android-distribution.md) settled who holds the Android release key and listed the price
of shipping outside a store: *"There is no discovery, no automatic update, and no Play channel."* It
also left the door open in rule 2 — *"If an update check is ever added it points at the project's
domain"* — and named the missing update path as **the sharpest edge of the decision** for a product sold
to teams.
[ADR 0013](0013-desktop-distribution-and-updates.md) then built exactly that for Windows, and the
argument it turns on applies here word for word: an SSH client holding a team's infrastructure
credentials is precisely the software where *"the fix shipped and the user never got it"* is a security
outcome rather than an inconvenience.
So the question is not whether the phone should update itself. It is how, given one Android fact that
decides everything else:
**An installed app can only be updated by a package signed with the same key.** Not "should not" —
Android refuses, with `INSTALL_FAILED_UPDATE_INCOMPATIBLE`. A key is an app's identity for its whole
life.
That collides with ADR 0011 rule 1, which puts the release key on a machine that is not a runner. CI can
build an APK; what it cannot do is sign one that any installed copy will accept, because the debug key it
falls back to is generated fresh in every container. An APK released from CI today could be installed
once and never updated again — and each "update" would require an uninstall, which on this product means
losing the local cache, the outbox and the device key.
## Decision
**Two channels, which are two applications, because Android has no third option.**
1. **`release``dev.dodotech.dodossh`, signed by the key ADR 0011 rule 1 describes.** Cut from a `v*`
tag by a person running `scripts/release-android.ps1` on a machine that is not a runner. No workflow
touches it, no secret exists for it, and CI has no job that could. ADR 0011 rule 1 is unchanged, and
its "Rejected" entry — *a release key held by CI so tagging cuts a release* — still stands.
2. **`nightly``dev.dodotech.dodossh.nightly`, signed by a keystore committed to this repository in the
open.** Cut from `main` by CI on every push, published as a pre-release on the project's own forge.
**The key is public on purpose, and that is what makes it safe to put in CI.** ADR 0011 rule 1 exists
because a key a workflow can reach is a key held by everyone who can change a workflow file. A key
everybody already has cannot be stolen, needs no secret to configure, and grants nothing by being
held — so the rule has nothing to protect. It also means this channel works on a fresh runner with no
setup, which is the practical reason it was reachable at all.
3. **Neither channel can update the other, by construction rather than by care.** Different package ids
and different keys, so a mistake is an install Android refuses rather than a nightly quietly replacing
somebody's real client. Both can be installed at once, which is the useful half: testing a nightly
costs nobody the build they rely on.
4. **The update check reads the project's forge and never the deployment**, which is ADR 0011 rule 2
applied unchanged. The feed address is a `const` in `AndroidUpdateChannel` and there is deliberately
no setting for it — a configurable update URL is exactly the knob that would let an operator, or a
stray edit to a plaintext file, point the update path at the party ADR 0001 models as the adversary.
**Which means the repository has to be public, and it was not.** A constant address with no token is
an anonymous read; the repository was private, so every check answered `404` and every phone reported
itself current. See ADR 0013 §4, which had written the incompatibility down as a fact about where a
token could live and not as something to check on the deployment. The check is one `curl` and it is
there.
The Android channel made it invisible rather than merely broken: it caught every network and parse
failure and answered null, which `IUpdateChannel` then documented as meaning "this build is current". So
a pressed CHECK NOW reported the latest build for an outage that had lasted since the feature shipped.
It throws now. The timer still swallows — a phone on a train is not news, and a half-published release
still fixes itself in six hours without anybody being told — and the button reports what happened,
which is the distinction `UpdateViewModel` was written to make and was never given anything to make it
with.
5. **The comparison is Android's `versionCode` and not the version name.** That integer is what the
platform itself uses to accept or refuse an install, so comparing anything else would let the client
offer an update the platform then rejects. The feed publishes it in a small JSON manifest beside the
APK — the counterpart of `releases.win.json` — so a check costs a few hundred bytes rather than a
download.
6. **Nothing is installed by the application.** It fetches, then asks Android to ask. The platform draws
its own confirmation naming the package, and from API 26 will not draw even that until the user has
turned this application on in the unknown-sources screen. Two deliberate answers, neither to a screen
DodoSSH controls.
◆ "Asks Android to ask" is one step longer than it sounds, and reading it as one step is why this
installed nothing at all from the day it shipped until 2026-08-05. An application holding only
`REQUEST_INSTALL_PACKAGES` gets no verdict back from committing a session: what the platform returns
first is `STATUS_PENDING_USER_ACTION`, carrying the confirmation activity in `Intent.EXTRA_INTENT` for
the application to start. **Android does not draw the dialogue on its own.** The commit succeeded, the
session staged, and nobody was ever asked anything. The receiver that starts it is
`InstallSessionReceiver`; the intent naming it has to be explicit, since a mutable pending intent
wrapping an implicit one is refused outright from API 34. Check 17.5 asks for exactly the right thing
— "Android's own installer appears naming the package" — so nothing needed rewording; it wants an
older build installed and a newer one published to run at all, and on the evidence it was never run
against a real pair.
7. **Applying does not end the process, and the shell had to learn that.** On Windows, applying replaces
the files and restarts, so the shell disposes the vault first — that is what zeroes the identity keys,
the vault keys and the cache key. On Android the install is a *request* and the answer may be no, so
disposing first would answer "not now" with a locked keychain and every shell closed. `IUpdateChannel`
gained `ApplyingEndsTheProcess`; where it is false the session is left alone, and the keys go when
Android kills the process on the install it agreed to.
## Consequences
**The nightly channel is a real attack surface and should be described as one.** Anyone can build an APK
a nightly phone will accept, because the key is public. Reaching one still means being what it fetches
from — a release on `git.dodotech.cloud` over TLS — so the practical set is *whoever can write a release
on this repository*, which is the same set ADR 0013 names for the desktop. That is acceptable for a
channel whose users are testing it and is not acceptable for the one holding people's credentials, which
is the entire reason there are two.
**A nightly is not a beta of the release channel; it is a different application.** Moving from one to the
other is an uninstall and a fresh enrolment. There is no migration and there will not be one — the two
caches are encrypted under keys held by two package identities the platform keeps apart.
**ADR 0011's "no automatic update" consequence is now wrong for the release channel and remains true for
reach.** Discovery, MDM deployment and the sideloading permission are all unchanged. What changed is only
that an installed copy can now learn a newer one exists.
**The release channel's `versionCode` stays a hand-bumped literal**, and forgetting to bump it is caught
rather than shipped: the release script reads what is already published and refuses to build a package
that does not beat it.
**Two identical launcher icons.** A nightly installed beside a release shows the same name under both.
Four ways to vary it per channel were tried and none reached the launcher label; the findings are in
`docs/platform-flags.md`. What tells them apart today is the package name in Android's app info, the
version, and the channel the application names on its own preferences screen.
## Rejected
- **A release keystore in CI so tagging cuts the real release.** The convenience is the point of CI and
the key is the point of ADR 0011; where they collide the key wins. This ADR is what makes that refusal
survivable rather than merely principled — the nightly channel is where the convenience went.
- **One channel, released from CI, signed with a stable key held as a secret.** This is the arrangement
most projects land on and it is ADR 0011's rejected entry with an extra step: the secret is reachable
by whoever can change a workflow file, and what it signs is the client holding the credentials.
- **Opening the release page in a browser instead of installing.** It would work, and it moves the same
APK through the same unknown-sources gate with one more step and no less trust. What it gives up is any
way of knowing a fix has been fetched, which is the property this ADR exists to buy.
- **A version-name comparison, so the feed could be a directory listing.** SemVer with prerelease heights
needs a parser, and the parser would disagree with the platform sooner or later. The number Android
uses is the number to compare.