## Why
Bubblewrap discovery probes executables before confinement. Excluding only the command's current directory leaves candidates in other writable roots eligible to run outside the sandbox.
## What changed
- Filter canonical `PATH` candidates using the filesystem policy and effective user permissions, including writable ancestors, symlinked roots, and full-disk write access. Preserve protected system installations while rejecting replaceable paths.
- Select the launcher with the command's permissions before the proc-mount preflight, retaining the bundled bubblewrap fallback.
- Use the effective permission profile and policy working directory for startup warning probes.
## Testing
Add unit coverage for writable roots, symlinks, read-only carveouts, replaceable parents, and full-disk policies. Add Linux integration tests showing writable `bwrap` candidates are neither probed nor launched, including when the command runs in a workspace subdirectory or uses managed networking with full-disk write access.
GitOrigin-RevId: 188c9f45e727eaace062f5abb1205dc23fdf3c51
## Why
Concurrent Linux test spawns can inherit writable descriptors for executable fixtures, preventing those fixtures from being executed even after the writing test closes its descriptor.
## What changed
Replace direct executable fixture writes and copies across the Rust tests with `codex_utils_cargo_bin::write_executable` and `copy_executable`. These existing helpers complete writes and copies in separate processes on Linux.
Remove the empty temporary inode before creating fake bubblewrap executables, and stage tampered bubblewrap bytes in a separate data file before copying them into the executable fixture. Add the required test dependencies.
GitOrigin-RevId: c875c83088731a4933ef1574e8d79d8cecc12f54
## Why
Approved commands need broader write access while retaining explicit read denials. On Linux, binding the filesystem root writable can shadow standard devices, and additional root-metadata mounts can reopen denied symlink targets.
## What changed
- Add `FileSystemSandboxPolicy::for_approved_command` to grant root and root-metadata writes while retaining path and glob denials. Keep the original policy when denials cannot be resolved or deny the root.
- Restore standard devices after Linux writable root binds, then apply explicit deny masks. Avoid redundant root-alias binds and inherit root-metadata writes from the root mount so denied targets stay masked.
- Preserve literal deny paths alongside resolved targets so Linux can reject denials that cross writable symlinks.
- Advertise Linux device and approved-root restriction support through two opt-in exec-server capabilities, omitted from serialization when false.
## Testing
Add regression coverage for approval policy materialization across Unix, Windows drive, and UNC paths; Windows volume expansion; Linux device access and metadata symlink restrictions; and capability serialization compatibility.
GitOrigin-RevId: 40584473da98a15e606bb1a8934308f69528850f
viyatb-oai