Abhinav
ab26554a3a
## Why Customers need finer-grained control over allowed sandbox modes based on the host Codex is running on. For example, they may want stricter sandbox limits on devboxes while keeping a different default elsewhere. Our current cloud requirements can target user/account groups, but they cannot vary sandbox requirements by host. That makes remote development environments awkward because the same top-level `allowed_sandbox_modes` has to apply everywhere. ## What Adds a new `remote_sandbox_config` section to `requirements.toml`: ```toml allowed_sandbox_modes = ["read-only"] [[remote_sandbox_config]] hostname_patterns = ["*.org"] allowed_sandbox_modes = ["read-only", "workspace-write"] [[remote_sandbox_config]] hostname_patterns = ["*.sh", "runner-*.ci"] allowed_sandbox_modes = ["read-only", "danger-full-access"] ``` During requirements resolution, Codex resolves the local host name once, preferring the machine FQDN when available and falling back to the cleaned kernel hostname. This host classification is best effort rather than authenticated device proof. Each requirements source applies its first matching `remote_sandbox_config` entry before it is merged with other sources. The shared merge helper keeps that `apply_remote_sandbox_config` step paired with requirements merging so new requirements sources do not have to remember the extra call. That preserves source precedence: a lower-precedence requirements file with a matching `remote_sandbox_config` cannot override a higher-precedence source that already set `allowed_sandbox_modes`. This also wires the hostname-aware resolution through app-server, CLI/TUI config loading, config API reads, and config layer metadata so they all evaluate remote sandbox requirements consistently. ## Verification - `cargo test -p codex-config remote_sandbox_config` - `cargo test -p codex-config host_name` - `cargo test -p codex-core load_config_layers_applies_matching_remote_sandbox_config` - `cargo test -p codex-core system_remote_sandbox_config_keeps_cloud_sandbox_modes` - `cargo test -p codex-config` - `cargo test -p codex-core` unit tests passed; `tests/all.rs` integration matrix was intentionally stopped after the relevant focused tests passed - `just fix -p codex-config` - `just fix -p codex-core` - `cargo check -p codex-app-server`
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. Codex also surfaces
a startup warning when bubblewrap cannot create user namespaces. WSL2 uses the
normal Linux bubblewrap path. WSL1 is not supported for bubblewrap sandboxing
because it cannot create the required user namespaces, so Codex rejects
sandboxed shell commands that would enter the bubblewrap path before invoking
bwrap.
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 elevated Windows sandbox also supports:
- legacy
ReadOnlyandWorkspaceWritebehavior - split filesystem policies that need exact readable roots, exact writable roots, or extra read-only carveouts under writable roots
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 can be enforced directly by the selected Windows backend or
round-trip through the legacy SandboxPolicy model without changing semantics.
Policies that would require direct explicit unreadable carveouts (none) or
reopened writable descendants under read-only carveouts 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.