## Summary
- adds macOS Seatbelt deny rules for unreadable glob patterns
- expands unreadable glob matches on Linux and masks them in bwrap,
including canonical symlink targets
- keeps Linux glob expansion robust when `rg` is unavailable in minimal
or Bazel test environments
- adds sandbox integration coverage that runs `shell` and `exec_command`
with a `**/*.env = none` policy and verifies the secret contents do not
reach the model
## Linux glob expansion
```text
Prefer: rg --files --hidden --no-ignore --glob <pattern> -- <search-root>
Fallback: internal globset walker when rg is not installed
Failure: any other rg failure aborts sandbox construction
```
```
[permissions.workspace.filesystem]
glob_scan_max_depth = 2
[permissions.workspace.filesystem.":project_roots"]
"**/*.env" = "none"
```
This keeps the common path fast without making sandbox construction
depend on an ambient `rg` binary. If `rg` is present but fails for
another reason, the sandbox setup fails closed instead of silently
omitting deny-read masks.
## Platform support
- macOS: subprocess sandbox enforcement is handled by Seatbelt regex
deny rules
- Linux: subprocess sandbox enforcement is handled by expanding existing
glob matches and masking them in bwrap
- Windows: policy/config/direct-tool glob support is already on `main`
from #15979; Windows subprocess sandbox paths continue to fail closed
when unreadable split filesystem carveouts require runtime enforcement,
rather than silently running unsandboxed
## Stack
1. #15979 - merged: cross-platform glob deny-read
policy/config/direct-tool support for macOS, Linux, and Windows
2. This PR - macOS/Linux subprocess sandbox enforcement plus Windows
fail-closed clarification
3. #17740 - managed deny-read requirements
## Verification
- Added integration coverage for `shell` and `exec_command` glob
deny-read enforcement
- `cargo check -p codex-sandboxing -p codex-linux-sandbox --tests`
- `cargo check -p codex-core --test all`
- `cargo clippy -p codex-linux-sandbox -p codex-sandboxing --tests`
- `just bazel-lock-check`
---------
Co-authored-by: Codex <noreply@openai.com>