Commit Graph
9 Commits
Author SHA1 Message Date
cairn-internandcairn-intern a3852bac59 fix(update): keep Windows failed-restore state in trusted recovery records (#979)
* fix(update): keep Windows failed-restore state in trusted recovery records

A failed restore currently records the last verified binary only as a
.deletable .keep marker in the install directory. Write an unresolved
identity-bound record to the existing per-user update-recovery store on
that failure path too, and consult it during preflight so deleting the
marker cannot silence the tamper refusal.

Fixes #868

* fix(update): keep a fail-closed signal if unresolved recovery records cannot be written

Ignoring a failed appendUnresolvedRecoveryRecord left only the sibling
.keep marker. An install-directory writer can delete that marker, after
which preflight finds no unresolved state and a retry can overwrite the
last verified recovery copy. Relocate that copy to a .recovery name when
the per-user record cannot be persisted so promotion still refuses.

Fixes #868

* fix(update): do not relocate the live binary when failed-restore compensation cannot record

persistFailedRestoreSignal relocated through the handle when the per-user
unresolved record could not be written, without checking that the object
was still the aside copy. A restore that had already put the verified
bytes back at targetPath then had that binary moved out of the executable
path. Verify identity with verifyPromotedTarget before relocating.

Unreadable recovery-state JSON now fails closed instead of looking like
an empty queue. The per-user vs per-machine split is documented: a second
account still relies on the install-directory .keep marker.

Fixes #868

* fix(update): durably commit recovery state on Windows

---------

Co-authored-by: cairn-intern <[email protected]>
2026-09-12 08:29:11 +08:00
cabfeefc4e security(update): stage binary replacement at an unpredictable, exclusive path (#751)
* security(update): stage binary replacement at an unpredictable, exclusive path

Fixes #742. installBinary staged downloaded release bytes at the fixed
<target>.new path and opened it with O_CREATE|O_WRONLY|O_TRUNC. In an
installation directory writable by a lower-privileged process, that
process could pre-create <target>.new as a hard link or reparse point
to another file the (possibly elevated) updater can write; the
truncating open then overwrote that unintended file with verified Zero
executable bytes.

stagingFilePath now generates a cryptographically random suffix so the
path can't be targeted in advance, and platform-specific
createStagingFile opens it exclusively without following a pre-existing
link: O_CREATE|O_EXCL on POSIX (which POSIX guarantees fails on a
pre-existing path, symlink or not, without resolving it), and
CreateFile with CREATE_NEW|FILE_FLAG_OPEN_REPARSE_POINT plus a
post-open GetFileInformationByHandle check on Windows (not a reparse
point, not a directory, single hard link).

replace_windows.go's rename-swap sequence is unchanged: the dangerous
operation was always the truncating open of the staged path, not the
.old rename/removal that follows.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

* security(update): bind the binary swap to the staged object, not its pathname

Addresses the two open findings on #751.

[P1] The staged file is no longer promoted by pathname. Randomizing the name
and creating it exclusively stops PRE-creation, but under #742's model — a
lower-privileged principal that can write in the installation directory — the
name can be observed after the fact and the entry replaced between the write and
the swap, so the updater would install the substituted file. installBinary now
keeps the creating handle open and promotes through it:

- Windows renames through the handle itself
  (SetFileInformationByHandle/FileRenameInfo, hence the added DELETE access), so
  there is no second pathname lookup to win. replaceBinary is gone; promote owns
  the aside-rename of the running binary and its restore-on-failure retry.
- POSIX has no rename-by-descriptor, so staging moves into a private directory
  created next to the target by os.MkdirTemp (mode 0700, random name, created
  exclusively). An attacker who can write in the installation directory cannot
  create, replace, or list entries inside it. promote additionally sets the
  executable bit through the handle (os.Chmod would re-resolve the path) and
  fails closed if the entry ever stops naming the object it wrote.

[P2] Staging cleanup now covers every failure path: the removal defer is
registered before the copy, and stageBinary discards the object if the copy
fails, so a mid-write error (ENOSPC, unreadable source) no longer leaks a
release-sized file that the next attempt will not reuse. CleanupStaleBinary also
sweeps leftovers from a hard crash — staging files on Windows, staging
directories on POSIX, where it used to be a no-op — skipping anything younger
than an hour so a concurrent update is never disturbed.

Tests: substitution-race regression per platform (Windows asserts the verified
bytes are installed despite a replaced staging entry; POSIX asserts the private
0700 directory and that promote refuses a substituted entry), success controls,
cleanup-on-failure, and the crash-leftover sweep. The forced-staging-failure test
for helper refresh now uses a stageBinary seam, because the staging location can
no longer be occupied from outside — which is the point of the fix.

* security(update): close remaining updater staging races

Address jatmn's review findings on PR #751:

- Windows promote() now verifies targetPath is actually reachable after a
  reported-successful handle rename before trusting it. Some Windows versions
  have been observed accepting SetFileInformationByHandle against a handle
  whose directory entry was substituted out from under it without the object
  actually moving, which let promote report success while targetPath was
  left missing entirely. renameFileByHandle is now a package var so this is
  covered by a deterministic regression test rather than relying on
  reproducing the exact trigger condition.

- When a promotion failure's restore-to-.old also fails (a writable-parent
  attacker occupying targetPath with a lock MOVEFILE_REPLACE_EXISTING can't
  get past), that combination is now wrapped in ErrTargetPossiblyTampered
  instead of reading like an ordinary failed update, with a best-effort
  MOVEFILE_DELAY_UNTIL_REBOOT fallback so an admin-context updater can still
  recover the original at next boot.

- POSIX promote() now binds its final rename to a directory descriptor
  opened when the staging directory is created (unix.Renameat), not a
  pathname. The 0700 staging directory protects its contents from a
  writable-parent principal, but not its own directory entry — that
  principal could rename the staging directory aside and recreate a
  look-alike with an attacker file at the same basename in the gap between
  the identity check and the rename, which a plain os.Rename would silently
  follow.

- Stale-cleanup on both platforms now matches the exact generated artifact
  shape (POSIX: prefix + os.MkdirTemp's all-digit suffix; Windows: prefix +
  32 lowercase hex chars + ".new") instead of a loose prefix/suffix, so a
  user's own similarly-named file or directory is never swept up. Both also
  re-check identity immediately before deleting to shrink the window a
  writable-parent principal could swap the checked path in.

- copyFrom now copies in chunks and refreshes the POSIX staging directory's
  mtime between them, since writing into an already-created file never
  touches the parent directory's own mtime — a large or slow copy could
  previously look abandoned to a concurrent update's cleanup sweep while
  still in progress.

Verified on real Windows and Linux (via WSL), plus cross-compiled build/vet
checks for darwin/linux-arm64.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

* fix(update): address staging review findings

* fix(update): verify promoted object identity safely

Bind POSIX staging creation and both rename endpoints to directory descriptors, clean only identity-matched empty directories, and verify Windows promotion by file identity rather than path spelling.

Preserve unverifiable crash leftovers and add adversarial cleanup, hard-link, and reparse-ancestor coverage.

Amp-Thread-ID: https://ampcode.com/threads/T-019fa019-27da-72ec-8e6d-5d43f127b6a1

Co-authored-by: Pierre Bruno <[email protected]>

* fix(update): preserve promotion recovery signals

Amp-Thread-ID: https://ampcode.com/threads/T-019fa7a0-1223-701d-9529-48ba5d7cf8c8

Co-authored-by: Pierre Bruno <[email protected]>

* fix(update): keep the recovery copy a failed restore promised

Two error-path follow-ups from the #742 staging review.

When a promotion fails and restoring the original also fails, the error tells
the operator their original is preserved at <binary>.old — and then the next
Apply deleted it, because a present target read as proof the copy was stale.
What occupies the target in exactly that case is the bytes the updater could
not verify, so cleanup was erasing the one it could. A failed restore now marks
the copy, cleanup honors the mark, and a successful promotion clears it.

The POSIX staging flow could also leave an empty .zero-stage-* directory behind
when the stat immediately after mkdirat failed. Nothing knows that name yet, so
it would have stayed for good; it is now removed best-effort with rmdir
semantics, which cannot touch anything but the empty directory just created.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

* fix(update): stop the recovery copy from being destroyed by the next attempt

The marker added in d9523ba kept cleanup from deleting <target>.old, but four
paths still undermined the promise it was meant to make.

Promotion destroyed the copy it was preserving. Skipping the pre-rename cleanup
was not enough: os.Rename uses MOVEFILE_REPLACE_EXISTING on Windows, so renaming
the running binary aside overwrote the last verified copy with the unverified
bytes the earlier failure left at the target — and a promotion that then failed
could only move those unverified bytes back. Promotion now refuses while the
tamper state is unresolved. Only the operator can say whether the file at the
target is theirs, so the error names both moves that end it: restore the copy,
or delete the marker to accept what is installed.

The marker itself was a predictable link-following truncate write. Its path is
fixed, so a writer in the install directory could pre-create it as a hard link
or reparse point and have the elevated updater write through it. It is now
created with the same CREATE_NEW + FILE_FLAG_OPEN_REPARSE_POINT + fresh-regular-
file check as a staging file, and never truncates; an existing name is treated
as already-marked rather than an object to open.

A marker that could not be written left the promise unqualified while the next
run's cleanup deleted exactly the file it named. That failure now rides in the
error, telling the operator to copy it somewhere safe now.

Helper refreshes downgraded tampering to a warning. An ordinary helper failure
still warns — a stale helper is better than a failed update — but a helper whose
path may hold unverified content fails the apply, because helpers are resolved
from the install directory and executed by the sandbox runner, and reporting
Applied: true would hand the operator a success while a sibling executable is
suspect. ErrTargetPossiblyTampered moved to apply.go so callers on every
platform can test for it without build tags.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

* fix(update): keep the recovery copy when its marker cannot be established

Surfacing a failed marker write told the operator to hurry; it did not stop the
next run from deleting the file they were being told to save. When no marker can
be established, the copy is now moved to an unpredictable sibling name that
routine cleanup never touches — CleanupStaleBinary only ever removes the exact
"<target>.old" — and the error names where it went. Telling the operator to act
now remains the fallback for when even that move fails.

The marker check is conservative in the same direction: only a definite
"not there" allows the copy to be deleted. An Lstat that fails for any other
reason leaves the question open, and deleting is irreversible while keeping
costs one stale file.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

* fix(update): preserve Windows recovery state across retries

Amp-Thread-ID: https://ampcode.com/threads/T-019faf74-99d4-75cf-ac7a-661c308240ef
Co-authored-by: Amp <[email protected]>

* fix(update): watch every recovery path and never orphan a partial marker

A failed second-or-later update marks the randomized aside it used, but
promotion only consulted the canonical <target>.old marker, so a retry
proceeded over an unverified target while the verified copy sat marked on a
path the refusal logic did not watch. Promotion now enumerates every recovery
candidate — canonical and randomized asides — and refuses while any of them
is marked, naming each recovery path and its marker.

The missing-target refusal had the same single-path blind spot: with a stale
canonical .old from an earlier successful update plus the aside from an
interrupted attempt, it named only the canonical path, which can be the wrong
binary. It now names the single actual candidate or refuses the ambiguous
layout outright until the operator resolves it.

A failed marker write could also leave a partial .keep behind while the
recovery copy was relocated elsewhere; later refusals then named a location
that no longer held the verified bytes. markOldBinaryPreserved now removes
the entry it created before reporting a write/close failure, and
conservatively reports success when that removal (or the state check) fails
so oldPath stays authoritative. keepUnmarkedRecoveryCopy is handle-bound end
to end: it pins the recovery copy with a no-delete-sharing, no-reparse open,
verifies it is a single-link regular file, renames through the handle with
ReplaceIfExists false, and confirms identity at the destination, failing
closed with ErrTargetPossiblyTampered on any race.

Finally, the error for an unestablishable marker still promised that a later
update would otherwise remove the copy, but CleanupStaleBinary is now a
no-op; the operator is told that a manual copy is required.

* fix(update): tolerate the fail-closed outcome of a fully-unlinked substitution

TestPromoteInstallsTheStagedObjectNotTheStagedPath deletes the staging
file's only directory entry and recreates it as an "attacker" file, then
required promote to succeed with the verified bytes installed. CI's
windows-latest runner permits that delete (this workstation's exclusive
share mode blocks it, so the path went unexercised here); on that runner,
renaming the now fully-unlinked staging handle back into existence is not
something every Windows build honors, so verifyPromotedTarget's post-
rename identity check finds nothing at targetPath, promote fails, and
restoreOriginalBinary moves the pre-update binary back — a safe, fail-
closed outcome, not a security regression.

The test now accepts either outcome after a real substitution: promote
succeeding with the verified bytes, or promote failing as long as the
attacker's substituted bytes were never installed. Any promote failure
that occurs without substitution having actually happened still fails
the test outright.

* fix(update): surface unverified recovery path, match .old case-insensitively

keepUnmarkedRecoveryCopy discarded the destination path when the rename
to it succeeded but the post-rename identity verification failed,
leaving restoreOriginalBinary's error telling the operator to save
oldPath after it had already been vacated. Return the attempted kept
path alongside the verification error so the caller can still name it.

existingRecoveryPaths compared "<target>.old" filenames case-sensitively,
but NTFS is case-insensitive/case-preserving, so a recovery or marker
file spelled e.g. "zero.exe.OLD" could be silently skipped by every
caller's fail-closed check. Fold both sides before matching.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

* fix(update): bound Windows recovery cleanup

Amp-Thread-ID: https://ampcode.com/threads/T-019fbdec-f8dc-71f9-abdd-ea044a902b9a
Co-authored-by: Pierre Bruno <[email protected]>

* fix(update): secure Windows recovery cleanup

Amp-Thread-ID: https://ampcode.com/threads/T-019fbec7-a912-7462-8938-1b4a8d95f1f3
Co-authored-by: Pierre Bruno <[email protected]>

* fix(update): terminate Windows rename paths

Amp-Thread-ID: https://ampcode.com/threads/T-019fbec7-a912-7462-8938-1b4a8d95f1f3
Co-authored-by: Pierre Bruno <[email protected]>

* test(update): allow namespaced recovery copies

Amp-Thread-ID: https://ampcode.com/threads/T-019fbec7-a912-7462-8938-1b4a8d95f1f3
Co-authored-by: Pierre Bruno <[email protected]>

* fix(update): bind Windows cleanup to handles, drop dead cleanup API

Failure-path staging cleanup on Windows re-resolved the staging pathname
after the exclusive handle was closed, so a principal who can write in the
installation directory could substitute that entry in the gap and have the
updater delete a file of their choosing. Removal is now requested through the
handle (FileDispositionInfo) before it is released, and nothing is removed by
name afterwards; the same change covers the staging-file verification failure
path and the partial recovery marker.

CleanupStaleBinary has had no production caller since bounded, identity-bound
cleanup moved into promote, so the exported no-op and the tests that could only
pass vacuously against it are removed. The POSIX link-regression tests now
drive createStagingFileAt, the primitive createStagedBinary actually uses,
instead of a path-taking helper kept alive only for them.

Also documents the fail-closed Windows recovery states in docs/UPDATE.md,
including the refusal a planted .old/.keep pair can cause.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

* fix(update): bind Windows recovery to handles and bound its state

Addresses the 2026-08-02 review round on #751.

Keep the recovery restore bound to the object promote moved aside instead
of its pathname: promote now opens the target with delete access and no
delete sharing before renaming it aside, and restoreOriginalBinary renames
that same handle back (retrying through the handle, never re-resolving the
source name), so a directory writer cannot swap the aside entry during the
promotion gap and have the substitute installed.

Run the recovery-state checks as a standalone-install precondition, under
the same lock promotion uses, so "already up to date" can no longer report
success while a .keep/.recovery state is unresolved. The in-promotion check
stays to close the race.

Make the cleanup record a queue: entries are only retired once their object
is actually gone, so a copy held open by a scanner is retried by a later
update rather than leaking, while records for paths that vanished or that
this updater could never have created are retired instead of accumulating.

Also from review of the above:
- delete the pathname restore chain that lost its production callers
  (restoreOriginalBinary's pathname form, openIdentityFile,
  recordRecoveryCleanup) and point their tests at the live handle path
- name the relocation path in the error when the post-move verification
  fails, since oldPath is already vacated by then
- scope the recovery docs to Windows and describe POSIX replace semantics

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

---------

Co-authored-by: Claude Sonnet 5 <[email protected]>
Co-authored-by: Amp <[email protected]>
2026-08-11 20:03:18 +08:00
1057d74512 docs(readme,cli): document /new & zero upgrade, add Discord link, and sync help text (#489)
* docs(readme): document /new, zero upgrade, and add Discord link

Add the /new slash command and zero upgrade command to the README's
command references, expand docs/UPDATE.md to cover the --apply install
flow, and link the project Discord server.

* docs(update): escape pipe in --endpoint table cell

CodeRabbit flagged the unescaped | in the --endpoint placeholder
breaking the Markdown table layout.

* docs(readme-zh): bring /new and zero upgrade in line with README.md

README_ZH.md had picked up the Discord link but was still missing the
/new slash command and zero upgrade entries added to README.md,
letting the translation drift out of sync.

* cli: add upgrade to root help output

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <[email protected]>

* docs: make required update flag explicit in common commands

zero update errors without --check or --apply, so the bare form in
the common-commands examples was misleading. Addresses the Copilot
finding from the PR #489 review.

* docs: use a permanent (non-expiring) Discord invite in the READMEs

* docs(cli): match upgrade help summary to download/verify/install wording

Copilot flagged the root zero --help summary for upgrade as less
specific than the download/verify/install phrasing already used in
README.md and docs/UPDATE.md for the same command.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

* docs: use discord.gg short link for the community invite

discord.com/invite/<code> and discord.gg/<code> resolve to the same
invite; discord.gg is the canonical short form to publish.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

* fix(update,readme-zh): keep npm --json stdout clean, add ZH Discussions route

`zero upgrade --json` (and `zero update --apply --json`) on an npm-managed
install wired npm's own stdout directly to the process stdout, so its
progress output landed ahead of the JSON result and made it unparseable.
Route npm's stdout into a buffer when JSON output is requested, only
surfacing it in the error message if the install fails.

README_ZH.md's Community section only pointed to Discord, unlike the
English README, which reserves Discord for real-time chat and routes
Q&A/ideas/sharing to GitHub Discussions per SUPPORT.md/CONTRIBUTING.md
policy. Bring the Chinese section in line with the same split.

Addresses the outstanding findings from jatmn's review on PR #489.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

* docs(update): qualify npm-managed JSON output

Document the npm subprocess output caveat instead of promising a single parseable JSON document for apply operations. Drop the JSON-specific updater plumbing and tests so the PR remains focused on documentation and help discovery.

Amp-Thread-ID: https://ampcode.com/threads/T-019fa55a-8bcd-71bc-9bde-9b4c28b78b38

Co-authored-by: Pierre Bruno <[email protected]>

* docs(update): align upgrade guidance

Amp-Thread-ID: https://ampcode.com/threads/T-019fa7a0-1223-701d-9529-48ba5d7cf8c8

Co-authored-by: Pierre Bruno <[email protected]>

* fix(update): keep the upgrade recommendation about this machine

`zero update --check --target windows-x64` answers a question about a different
machine, but the new call to action told the user to run `zero upgrade`, which
only ever installs onto this one — replacing the target-specific download
guidance the flag used to print. The recommendation is now conditional: a
current-platform check keeps it, and a cross-target check gets the manual
instruction plus a note naming the machine `zero upgrade` would have touched
instead.

Also align two flag contracts with what the code does: `zero update --help`
described --repo/--endpoint as check-only although apply honors them, and
UPDATE.md did not mention that both are ignored on an npm-managed apply, which
takes its release from the npm registry rather than GitHub.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

* fix(update): do not send a custom-source check to the default source

`zero upgrade` is a fresh invocation: it does not inherit the --repo/--endpoint
of the check that suggested it, so recommending it bare after a custom-source
check told the user to install from a repository they never asked about. The
check now records the flag it was given and the guidance repeats it, naming
where a bare upgrade would install from instead.

ZERO_UPDATE_RELEASE_URL is deliberately not recorded: every Check reads it from
the environment, including the one inside Apply, so a bare upgrade already
follows it and telling the user to repeat it would be wrong.

Two smaller edges from the same review: a cross-target check on a host with no
published release target no longer ends by describing what `zero upgrade` does
there, since it does not work there at all; and the flag table and help text now
carry the npm caveat the prose bullet already had, so docs and help agree.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

* fix(update): keep source guidance accurate

Amp-Thread-ID: https://ampcode.com/threads/T-019fafa2-7d9d-75bc-8801-6d0efc8db1df
Co-authored-by: Pierre Bruno <[email protected]>

---------

Co-authored-by: Copilot Autofix powered by AI <[email protected]>
Co-authored-by: Vasanthdev2004 <[email protected]>
Co-authored-by: Claude Sonnet 5 <[email protected]>
Co-authored-by: Amp <[email protected]>
2026-08-10 07:32:53 +08:00
Anandan 726f1512a3 Clean up public release docs (#339)
Rewrite the README around the initial public-release user flow, add the logo asset, and refresh install/update documentation.

Remove internal planning, audit, design, and work-split documents from the public docs tree.

Update stale documentation references and workspace seed expectations to point at public docs.

Tested: env GOCACHE=/tmp/zero-go-cache go test ./internal/workspaceseed

Tested: git diff --check
2026-06-28 17:13:21 +05:30
Anandan 699df010e2 feat(update): verify release metadata by target (#97)
* Add update check target selection

* Reject empty update target flag
2026-06-06 15:58:41 +05:30
Anandan 3e4add95ab feat(update): expose release check target options (#96)
* Expose update check target options

* Reject non-positive update timeouts
2026-06-06 15:28:50 +05:30
Anandan 04808f6abd Verify update release assets (#84) 2026-06-06 11:16:44 +05:30
Anandan f9de264e9b feat: add M2 install scripts (#19)
* Add M2 install scripts

* Harden install archive extraction

* Fix install script runtime test platform
2026-06-03 09:57:08 +05:30
Anandan b801c532ef feat: add M2 update check (#16)
* Add M2 update check command

* Harden update check version and timeout
2026-06-03 09:30:00 +05:30