Users are always granted permissions to cd into a directory. The check for whether execute is present on directories is a de-facto no-op. This cannot be mitigated without upgrading. Even setting an explicit "deny - execute" NFSv4 ACE will be bypassed.
All ACEs for the owner_group (group@) and regular groups (group:<foo>) are granted the current user. This means that POSIX mode 770 is de-facto 777, and the below ACL is also de-facto 777 because the groupmember check for builtin_administrators returns True.
root@TNBETA1[~]# getfacl testfile # file: testfile # owner: root # group: wheel group:builtin_administrators:rwxpDdaARWcCos:-------:allow
This currently affects FreeBSD port of openzfs.
12.x BETA1/BETA2/MASTER and sysutils/openzfs-kmod are impacted.
- Upstream Fix: OpenZFS Commit: https://github.com/openzfs/zfs/commit/716b53d0a14c72bda16c0872565dd1909757e73f
- Ports Code fix: https://reviews.freebsd.org/D26107