Reviewing 46799dad against a real tree: severMemberTree reassigns ownership and leaves the
access-control entries behind. confineUserTree grants each member a named ACL on their whole
tree — u:<uid>:rwx plus a default: copy — and chown does not remove them. They are xattrs
rather than ownership, and they store the uid NUMERICALLY.
Measured: chown -h -R to the service user leaves user:<uid>:rwx intact on the directory, its
children and their defaults. So a preserved tree owned by the platform still grants the freed
uid read and write on every byte, and the next account allocated that number inherits the
previous member's home, SSH keys, credentials, transcripts and container storage. That is the
hazard the function exists to prevent, reached through ACLs instead of ownership.
This was my omission as much as the implementation's: the spec said "sever the data from the
uid" and specified only chown, and assert-uid-free.sh checked find -uid, which reads ownership
and cannot see an ACL. Both are fixed here — the spec now requires setfacl -R -b alongside the
chown, and the checker scans DATA_PATH with getfacl -R -n for entries naming the freed uid.
The checker was verified to catch it: run against green's live tree it now reports
"ACL entries still grant uid 1001 (user:1001:rwx)", which it did not before.
The code fix is one line in severMemberTree and is not mine to make.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
pastilhasandClaude Opus 5
a2f63dc534