## Summary This PR makes Windows sandbox proxying enforceable by routing proxy-only runs through the existing `offline` sandbox user and reserving direct network access for the existing `online` sandbox user. In brief: - if a Windows sandbox run should be proxy-enforced, we run it as the `offline` user - the `offline` user gets firewall rules that block direct outbound traffic and only permit the configured localhost proxy path - if a Windows sandbox run should have true direct network access, we run it as the `online` user - no new sandbox identity is introduced This brings Windows in line with the intended model: proxy use is not just env-based, it is backed by OS-level egress controls. Windows already has two sandbox identities: - `offline`: intended to have no direct network egress - `online`: intended to have full network access This PR makes proxy-enforced runs use that model directly. ### Proxy-enforced runs When proxy enforcement is active: - the run is assigned to the `offline` identity - setup extracts the loopback proxy ports from the sandbox env - Windows setup programs firewall rules for the `offline` user that: - block all non-loopback outbound traffic - block loopback UDP - block loopback TCP except for the configured proxy ports - optionally allow broader localhost access when `allow_local_binding=1` So the sandboxed process can only talk to the local proxy. It cannot open direct outbound sockets or do local UDP-based DNS on its own.The proxy then performs the real outbound network access outside that restricted sandbox identity. ### Direct-network runs When proxy enforcement is not active and full network access is allowed: - the run is assigned to the `online` identity - no proxy-only firewall restrictions are applied - the process gets normal direct network access ### Unelevated vs elevated The restricted-token / unelevated path cannot enforce per-identity firewall policy by itself. So for Windows proxy-enforced runs, we transparently use the logon-user sandbox path under the hood, even if the caller started from the unelevated mode. That keeps enforcement real instead of best-effort. --------- Co-authored-by: Codex <noreply@openai.com>
codex-core
This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.
Dependencies
Note that codex-core makes some assumptions about certain helper utilities being available in the environment. Currently, this support matrix is:
macOS
Expects /usr/bin/sandbox-exec to be present.
When using the workspace-write sandbox policy, the Seatbelt profile allows
writes under the configured writable roots while keeping .git (directory or
pointer file), the resolved gitdir: target, and .codex read-only.
Network access and filesystem read/write roots are controlled by
SandboxPolicy. Seatbelt consumes the resolved policy and enforces it.
Seatbelt also keeps the legacy default preferences read access
(user-preference-read) needed for cfprefs-backed macOS behavior.
Linux
Expects the binary containing codex-core to run the equivalent of codex sandbox linux (legacy alias: codex debug landlock) when arg0 is codex-linux-sandbox. See the codex-arg0 crate for details.
Legacy SandboxPolicy / sandbox_mode configs are still supported on Linux.
They can continue to use the legacy Landlock path when the split filesystem
policy is sandbox-equivalent to the legacy model after cwd resolution.
Split filesystem policies that need direct FileSystemSandboxPolicy
enforcement, such as read-only or denied carveouts under a broader writable
root, automatically route through bubblewrap. The legacy Landlock path is used
only when the split filesystem policy round-trips through the legacy
SandboxPolicy model without changing semantics. That includes overlapping
cases like /repo = write, /repo/a = none, /repo/a/b = write, where the
more specific writable child must reopen under a denied parent.
The Linux sandbox helper prefers the first bwrap found on PATH outside the
current working directory whenever it is available. If bwrap is present but
too old to support --argv0, the helper keeps using system bubblewrap and
switches to a no---argv0 compatibility path for the inner re-exec. If
bwrap is missing, it falls back to the vendored bubblewrap path compiled into
the binary and Codex surfaces a startup warning through its normal notification
path instead of printing directly from the sandbox helper.
Windows
Legacy SandboxPolicy / sandbox_mode configs are still supported on
Windows.
The elevated setup/runner backend supports legacy ReadOnlyAccess::Restricted
for read-only and workspace-write policies. Restricted read access honors
explicit readable roots plus the command cwd, and keeps writable roots
readable when workspace-write is used.
When include_platform_defaults = true, the elevated Windows backend adds
backend-managed system read roots required for basic execution, such as
C:\Windows, C:\Program Files, C:\Program Files (x86), and
C:\ProgramData. When it is false, those extra system roots are omitted.
The unelevated restricted-token backend still supports the legacy full-read
Windows model for legacy ReadOnly and WorkspaceWrite behavior. It also
supports a narrow split-filesystem subset: full-read split policies whose
writable roots still match the legacy WorkspaceWrite root set, but add extra
read-only carveouts under those writable roots.
New [permissions] / split filesystem policies remain supported on Windows
only when they round-trip through the legacy SandboxPolicy model without
changing semantics. Policies that would require direct read restriction,
explicit unreadable carveouts, reopened writable descendants under read-only
carveouts, different writable root sets, or split carveout support in the
elevated setup/runner backend still fail closed instead of running with weaker
enforcement.
All Platforms
Expects the binary containing codex-core to simulate the virtual apply_patch CLI when arg1 is --codex-run-as-apply-patch. See the codex-arg0 crate for details.