fix(security): fail-closed gh gate for external projects (LIA-361)#1013
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The tool-proxy push/merge gate only flagged `gh merge` / `gh pr merge|create` by subcommand position, so `gh api -X PUT .../pulls/1/merge` -- and `gh alias`, `gh extension`, `gh secret`, etc. -- ran with the host operator's GitHub credentials from a non-allowlisted external-project container, bypassing the externalPushDenialReason trust boundary (LIA-180). Flip `isPushOrMergeTool`'s `gh` handling from a denylist to a fail-closed allowlist: only an explicit set of read subcommands (pr/issue/repo/release/run/ workflow view|list|..., gh search <target>) and a provably-GET `gh api` pass through; every other subcommand -- including alias/extension (which persist an alias or install code that later runs with host creds) and any unknown one -- is gated. `gh api` mutation detection uses a real POSIX shorthand-cluster walk, not string-prefix matching, so `-if k=v` / `-iX PUT` (a value flag hidden behind the boolean `-i`/`--include`) and glued/`=`/dangling/long forms are all caught, plus a defense-in-depth scan for an X-HTTP-Method-Override header. Only affects untrusted external projects: externalPushDenialReason still returns null for the home/control project and allowlisted external projects, unchanged. Tests: independent oracle suite (authored blind to the implementation) + a regression block for the shorthand-cluster bypass. Full suite green (1990). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
sliamh11
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Jul 17, 2026
🤖 I have created a release *beep* *boop* --- ## [1.27.0](v1.26.0...v1.27.0) (2026-07-17) ### Features * **deus-v2:** validate subscription billing through credential proxy (LIA-397) ([#1035](#1035)) ([38aa247](38aa247)) ### Bug Fixes * **admin-merge-gate:** allow admin-merge on plan-limited private repos ([#1055](#1055)) ([8d283a9](8d283a9)) * **admin-merge-gate:** exclude known-advisory checks from plan-limited fallback ([#1056](#1056)) ([8e67e6a](8e67e6a)) * **admin-merge-gate:** scope internal gh calls to the gated command's --repo ([#1054](#1054)) ([545b941](545b941)) * **code-search:** sweep orphaned rowids from vec/fts on reindex (LIA-368) ([#1042](#1042)) ([fad4885](fad4885)) * **ingress:** don't kill the OAuth refresh timer on a port-conflict retry (LIA-363) ([#1020](#1020)) ([0cf61dd](0cf61dd)) * **memory:** exclude orphaned entries from FTS query (LIA-370) ([#1040](#1040)) ([0645453](0645453)) * **memory:** re-embed nodes missing an embedding row (LIA-369) ([#1041](#1041)) ([f2855b0](f2855b0)) * **memory:** repair entries_fts write-path drift (LIA-370) ([#1043](#1043)) ([1414898](1414898)) * **runtime:** handle stream errors on tool-proxy req + container stdin (LIA-362, LIA-385) ([#1021](#1021)) ([df9df3f](df9df3f)) * **security:** fail-closed gh gate for external projects (LIA-361) ([#1013](#1013)) ([ee9b62e](ee9b62e)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).
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What
Closes the
gh apicredential-escalation bypass found by the 2026-07-03 system audit (V2 re-audit re-confirmed it live on origin/main). Roadmap step 2, PR 1 of 3.The tool-proxy push/merge gate only flagged
gh merge/gh pr merge|createby subcommand position.gh api -X PUT .../pulls/1/merge— andgh alias set,gh extension install,gh secret set, etc. — matched none of the guarded tokens and ran with the host operator's real GitHub credentials from a non-allowlisted external-project container, bypassingexternalPushDenialReason(the LIA-180 trust boundary).How
isPushOrMergeTool'sghhandling flips from a denylist (allow unless recognized-bad) to a fail-closed allowlist:pr/issue/repo/release/run/workflow view|list|…,gh search <code|commits|issues|prs|repos>) and a provably-GETgh apipass through.alias/extension(persist an alias / install code that later runs with host creds),secret,pr merge|create|close, and any unknown subcommand — is gated.gh apimutation detection uses a real POSIX shorthand-cluster walk, not string-prefix matching, so-if k=v/-iX PUT(a value flag hidden behind the boolean-i/--include), plus glued/=/dangling/long forms, are all caught. Defense-in-depth scan for anX-HTTP-Method-Overrideheader.Only untrusted external projects are affected:
externalPushDenialReasonstill returnsnullfor the home/control project and allowlisted external projects (unchanged).Review trail
alias/extensionbypass → flipped to allowlist).gh api -if k=vPOSIX-cluster hid the value flag; verified executing a live POST against realghv2.92.0) → fixed with the cluster walker → round-2 SHIP.Co-Authored-By: Claude Opus 4.8 noreply@anthropic.com