[seradotcom]

Change and reason

A native Windows executable with an explicit or inherited read/execute ACL for another principal was rejected as writable. The admission check intersected each ACE with FILE_GENERIC_WRITE, whose expanded mask also contains READ_CONTROL and SYNCHRONIZE.

Use concrete mutation rights plus GENERIC_WRITE/GENERIC_ALL instead. Apply the same correction to private-file read checks while explicitly retaining FILE_READ_DATA, FILE_READ_EA and FILE_READ_ATTRIBUTES, so private data and attribute reads remain denied.

Verification actually executed

• Regression-first commit: 385d4ed. Windows run 39004484744 failed on x64 and ARM64 at the new ACL regression step. Both architecture logs record 4 passing rejection tests and 4 failing acceptance tests with the exact DACL rejection, including explicit/inherited executable R and private-file RC grants.
• Fix commit: cf321a5. Windows run 39004850922 passed both complete native noninteractive jobs (x64 and ARM64) and both sealed-tool compatibility jobs. On each native architecture, all 8 new ACL tests and 3 existing private-data tests passed with no ignored/filtered cases, covering 66 explicit/inherited ACL combinations in the new suite. Runtime check, Clippy, broader runtime/Host tests, documentation and fixture compilation also passed.
• Runtime tools portability run 39004850882 passed the Windows/Linux Host jobs and Windows/Linux/macOS SDK jobs. Quality gates passed; unrelated application-engine/fuzz lanes were correctly skipped by path scope, not counted as native tests.
• Local cargo fmt --all -- --check, git diff --check and 4 Windows Python contract tests passed. Heavy native compilation/tests run on disposable CI in accordance with repository policy.
• A separate agent reviewed the final sources and found no actionable issues, conditional on green Windows CI. This is not an external security audit or maintainer approval.

Permissions / protocols / compatibility affected

Windows file admission now permits harmless shared standard rights while retaining all existing concrete write/delete/owner/DACL restrictions and private data/EA/attribute read restrictions. Broker grants, approval policy and confirm_mutations are unchanged. Installed binaries and running application bridges were not modified or restarted. No new dependency or protocol change. Reverting the mask change restores the previous false-positive behavior.

Regression fixture

Eight tests exercise real temporary-file ACLs via the public executable/private-file verifiers, using an untrusted Everyone principal with explicit grants or grants inherited from a protected temporary parent. They cover executable R/RX/RA/REA/RC/S acceptance, individual and aggregate mutation denial, private-file RC/S acceptance, and private data/attribute/EA read and mutation denial. The Windows workflow runs these fixtures before the broader runtime checks on x64 and ARM64.