## Stack
fix: fail closed for unsupported split windows sandboxing #14172
-> fix: preserve split filesystem semantics in linux sandbox #14173
fix: align core approvals with split sandbox policies #14171
refactor: centralize filesystem permissions precedence #14174
## Summary
## Summary
- Preserve Linux split filesystem carveouts in bubblewrap by applying
mount masks in the right order, so narrower rules still win under
broader writable roots.
- Preserve unreadable ancestors of writable roots by masking them first
and then rebinding the narrower writable descendants.
- Stop rejecting legacy-plus-split Linux configs that are
sandbox-equivalent after `cwd` resolution by comparing semantics instead
of raw legacy structs.
- Fail closed when callers provide partial split policies, mismatched
legacy-plus-split policies, or force `--use-legacy-landlock` for
split-only shapes that legacy Landlock cannot enforce.
- Add Linux regressions for overlapping writable, read-only, and denied
paths, and document the supported split-policy enforcement path.
## Example
Given a split filesystem policy like:
```toml
[permissions.dev.filesystem]
":root" = "read"
"/code" = "write"
"/code/.git" = "read"
"/code/secrets" = "none"
"/code/secrets/tmp" = "write"
```
this PR makes Linux enforce the intended result under bubblewrap:
- `/code` stays writable
- `/code/.git` stays read-only
- `/code/secrets` stays denied
- `/code/secrets/tmp` can still be reopened as writable if explicitly
allowed
Before this, Linux could lose one of those carveouts depending on mount
order or legacy-policy fallback. This PR keeps the split-policy
semantics intact and rejects configurations that legacy Landlock cannot
represent safely.
## Summary
- address the follow-up review nits from #13996 in a separate PR
- make the approvals test command a raw string and keep the
managed-network path using env proxy routing
- inline `--apply-seccomp-then-exec` in the Linux sandbox inner command
builder
- remove the bubblewrap-specific sandbox metric tag path and drop the
`use_legacy_landlock` shim from `sandbox_tag`/`TurnMetadataState::new`
- restore the `Feature` import that `origin/main` currently still needs
in `connectors.rs`
## Testing
- `cargo test -p codex-linux-sandbox`
- focused `codex-core` tests were rerun/started, but the final
verification pass was interrupted when I pushed at request
## Summary
- make bubblewrap the default Linux sandbox and keep
`use_legacy_landlock` as the only override
- remove `use_linux_sandbox_bwrap` from feature, config, schema, and
docs surfaces
- update Linux sandbox selection, CLI/config plumbing, and related
tests/docs to match the new default
- fold in the follow-up CI fixes for request-permissions responses and
Linux read-only sandbox error text
## Summary
This is a fast follow to the initial `[permissions]` structure.
- keep the new split-policy carveout behavior for narrower non-write
entries under broader writable roots
- preserve legacy `WorkspaceWrite` semantics by using a cwd-aware bridge
that drops only redundant nested readable roots when projecting from
`SandboxPolicy`
- route the legacy macOS seatbelt adapter through that same legacy
bridge so redundant nested readable roots do not become read-only
carveouts on macOS
- derive the legacy bridge for `command_exec` using the sandbox root cwd
rather than the request cwd so policy derivation matches later sandbox
enforcement
- add regression coverage for the legacy macOS nested-readable-root case
## Examples
### Legacy `workspace-write` on macOS
A legacy `workspace-write` policy can redundantly list a nested readable
root under an already-writable workspace root.
For example, legacy config can effectively mean:
- workspace root (`.` / `cwd`) is writable
- `docs/` is also listed in `readable_roots`
The new shared split-policy helper intentionally treats a narrower
non-write entry under a broader writable root as a carveout for real
`[permissions]` configs. Without this fast follow, the unchanged macOS
seatbelt legacy adapter could project that legacy shape into a
`FileSystemSandboxPolicy` that treated `docs/` like a read-only carveout
under the writable workspace root. In practice, legacy callers on macOS
could unexpectedly lose write access inside `docs/`, even though that
path was writable before the `[permissions]` migration work.
This change fixes that by routing the legacy seatbelt path through the
cwd-aware legacy bridge, so:
- legacy `workspace-write` keeps `docs/` writable when `docs/` was only
a redundant readable root
- explicit `[permissions]` entries like `'.' = 'write'` and `'docs' =
'read'` still make `docs/` read-only, which is the new intended
split-policy behavior
### Legacy `command_exec` with a subdirectory cwd
`command_exec` can run a command from a request cwd that is narrower
than the sandbox root cwd.
For example:
- sandbox root cwd is `/repo`
- request cwd is `/repo/subdir`
- legacy policy is still `workspace-write` rooted at `/repo`
Before this fast follow, `command_exec` derived the legacy bridge using
the request cwd, but the sandbox was later built using the sandbox root
cwd. That mismatch could miss redundant legacy readable roots during
projection and accidentally reintroduce read-only carveouts for paths
that should still be writable under the legacy model.
This change fixes that by deriving the legacy bridge with the same
sandbox root cwd that sandbox enforcement later uses.
## Verification
- `just fmt`
- `cargo test -p codex-core
seatbelt_legacy_workspace_write_nested_readable_root_stays_writable`
- `cargo test -p codex-core test_sandbox_config_parsing`
- `cargo clippy -p codex-core -p codex-app-server --all-targets -- -D
warnings`
- `cargo clean`
## Why
After `#13449`, the Linux helper could receive split filesystem and
network policies, but the bubblewrap mount builder still reconstructed
filesystem access from the legacy `SandboxPolicy`.
That loses explicit unreadable carveouts under writable roots, and it
also mishandles `Root` read access paired with explicit deny carveouts.
In those cases bubblewrap could still expose paths that the split
filesystem policy intentionally blocked.
## What changed
- switched bubblewrap mount generation to consume
`FileSystemSandboxPolicy` directly at the implementation boundary;
legacy `SandboxPolicy` configs still flow through the existing
`FileSystemSandboxPolicy::from(&sandbox_policy)` bridge before reaching
bwrap
- kept the Linux helper and preflight path on the split filesystem
policy all the way into bwrap
- re-applied explicit unreadable carveouts after readable and writable
mounts so blocked subpaths still win under bubblewrap
- masked denied directories with `--tmpfs` plus `--remount-ro` and
denied files with `--ro-bind-data`, preserving the backing fd until exec
- added comments in the unreadable-root masking block to explain why the
mount order and directory/file split are intentional
- updated Linux helper call sites and tests for the split-policy bwrap
path
## Verification
- added protocol coverage for root carveouts staying scoped
- added core coverage that root-write plus deny carveouts still requires
a platform sandbox
- added bwrap unit coverage for reapplying blocked carveouts after
writable binds
- added Linux integration coverage for explicit split-policy carveouts
under bubblewrap
- validated the final branch state with `cargo test -p
codex-linux-sandbox`, `cargo clippy -p codex-linux-sandbox --all-targets
-- -D warnings`, and the PR CI reruns
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/13453).
* __->__ #13453
* #13452
* #13451
* #13449
* #13448
* #13445
* #13440
* #13439
---------
Co-authored-by: viyatb-oai <viyatb@openai.com>
## Why
The Linux sandbox helper still only accepted the legacy `SandboxPolicy`
payload.
That meant the runtime could compute split filesystem and network
policies, but the helper would immediately collapse them back to the
compatibility projection before applying seccomp or staging the
bubblewrap inner command.
## What changed
- added hidden `--file-system-sandbox-policy` and
`--network-sandbox-policy` flags alongside the legacy `--sandbox-policy`
flag so the helper can migrate incrementally
- updated the core-side Landlock wrapper to pass the split policies
explicitly when launching `codex-linux-sandbox`
- added helper-side resolution logic that accepts either the legacy
policy alone or a complete split-policy pair and normalizes that into
one effective configuration
- switched Linux helper network decisions to use `NetworkSandboxPolicy`
directly
- added `FromStr` support for the split policy types so the helper can
parse them from CLI JSON
## Verification
- added helper coverage in `linux-sandbox/src/linux_run_main_tests.rs`
for split-policy flags and policy resolution
- added CLI argument coverage in `core/src/landlock.rs`
- verified the current PR state with `just clippy`
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/13449).
* #13453
* #13452
* #13451
* __->__ #13449
* #13448
* #13445
* #13440
* #13439
---------
Co-authored-by: viyatb-oai <viyatb@openai.com>
## Why
`codex-rs/core/src/lib.rs` re-exported a broad set of types and modules
from `codex-protocol` and `codex-shell-command`. That made it easy for
workspace crates to import those APIs through `codex-core`, which in
turn hides dependency edges and makes it harder to reduce compile-time
coupling over time.
This change removes those public re-exports so call sites must import
from the source crates directly. Even when a crate still depends on
`codex-core` today, this makes dependency boundaries explicit and
unblocks future work to drop `codex-core` dependencies where possible.
## What Changed
- Removed public re-exports from `codex-rs/core/src/lib.rs` for:
- `codex_protocol::protocol` and related protocol/model types (including
`InitialHistory`)
- `codex_protocol::config_types` (`protocol_config_types`)
- `codex_shell_command::{bash, is_dangerous_command, is_safe_command,
parse_command, powershell}`
- Migrated workspace Rust call sites to import directly from:
- `codex_protocol::protocol`
- `codex_protocol::config_types`
- `codex_protocol::models`
- `codex_shell_command`
- Added explicit `Cargo.toml` dependencies (`codex-protocol` /
`codex-shell-command`) in crates that now import those crates directly.
- Kept `codex-core` internal modules compiling by using `pub(crate)`
aliases in `core/src/lib.rs` (internal-only, not part of the public
API).
- Updated the two utility crates that can already drop a `codex-core`
dependency edge entirely:
- `codex-utils-approval-presets`
- `codex-utils-cli`
## Verification
- `cargo test -p codex-utils-approval-presets`
- `cargo test -p codex-utils-cli`
- `cargo check --workspace --all-targets`
- `just clippy`
## Summary
- Updates the Linux bubblewrap sandbox args to mount a minimal `/dev`
using `--dev /dev` instead of only binding `/dev/null`. tools needing
entropy (git, crypto libs, etc.) can fail.
- Changed mount order so `--dev /dev` is added before writable-root
`--bind` mounts, preserving writable `/dev/*` submounts like `/dev/shm`
## Why
Fixes sandboxed command failures when reading `/dev/urandom` (and
similar standard device-node access).
Fixes https://github.com/openai/codex/issues/12056
`SandboxPolicy::ReadOnly` previously implied broad read access and could
not express a narrower read surface.
This change introduces an explicit read-access model so we can support
user-configurable read restrictions in follow-up work, while preserving
current behavior today.
It also ensures unsupported backends fail closed for restricted-read
policies instead of silently granting broader access than intended.
## What
- Added `ReadOnlyAccess` in protocol with:
- `Restricted { include_platform_defaults, readable_roots }`
- `FullAccess`
- Updated `SandboxPolicy` to carry read-access configuration:
- `ReadOnly { access: ReadOnlyAccess }`
- `WorkspaceWrite { ..., read_only_access: ReadOnlyAccess }`
- Preserved existing behavior by defaulting current construction paths
to `ReadOnlyAccess::FullAccess`.
- Threaded the new fields through sandbox policy consumers and call
sites across `core`, `tui`, `linux-sandbox`, `windows-sandbox`, and
related tests.
- Updated Seatbelt policy generation to honor restricted read roots by
emitting scoped read rules when full read access is not granted.
- Added fail-closed behavior on Linux and Windows backends when
restricted read access is requested but not yet implemented there
(`UnsupportedOperation`).
- Regenerated app-server protocol schema and TypeScript artifacts,
including `ReadOnlyAccess`.
## Compatibility / rollout
- Runtime behavior remains unchanged by default (`FullAccess`).
- API/schema changes are in place so future config wiring can enable
restricted read access without another policy-shape migration.
## Summary
This PR introduces a gated Bubblewrap (bwrap) Linux sandbox path. The
curent Linux sandbox path relies on in-process restrictions (including
Landlock). Bubblewrap gives us a more uniform filesystem isolation
model, especially explicit writable roots with the option to make some
directories read-only and granular network controls.
This is behind a feature flag so we can validate behavior safely before
making it the default.
- Added temporary rollout flag:
- `features.use_linux_sandbox_bwrap`
- Preserved existing default path when the flag is off.
- In Bubblewrap mode:
- Added internal retry without /proc when /proc mount is not permitted
by the host/container.
## Summary
Vendor Bubblewrap into the repo and add minimal build plumbing in
`codex-linux-sandbox` to compile/link it.
## Why
We want to move Linux sandboxing toward Bubblewrap, but in a safe
two-step rollout:
1) vendoring/build setup (this PR),
2) runtime integration (follow-up PR).
## Included
- Add `codex-rs/vendor/bubblewrap` sources.
- Add build-time FFI path in `codex-rs/linux-sandbox`.
- Update `build.rs` rerun tracking for vendored files.
- Small vendored compile warning fix (`sockaddr_nl` full init).
follow up in https://github.com/openai/codex/pull/9938
This is a major redesign of how sandbox configuration works and aims to
fix https://github.com/openai/codex/issues/1248. Specifically, it
replaces `sandbox_permissions` in `config.toml` (and the
`-s`/`--sandbox-permission` CLI flags) with a "table" with effectively
three variants:
```toml
# Safest option: full disk is read-only, but writes and network access are disallowed.
[sandbox]
mode = "read-only"
# The cwd of the Codex task is writable, as well as $TMPDIR on macOS.
# writable_roots can be used to specify additional writable folders.
[sandbox]
mode = "workspace-write"
writable_roots = [] # Optional, defaults to the empty list.
network_access = false # Optional, defaults to false.
# Disable sandboxing: use at your own risk!!!
[sandbox]
mode = "danger-full-access"
```
This should make sandboxing easier to reason about. While we have
dropped support for `-s`, the way it works now is:
- no flags => `read-only`
- `--full-auto` => `workspace-write`
- currently, there is no way to specify `danger-full-access` via a CLI
flag, but we will revisit that as part of
https://github.com/openai/codex/issues/1254
Outstanding issue:
- As noted in the `TODO` on `SandboxPolicy::is_unrestricted()`, we are
still conflating sandbox preferences with approval preferences in that
case, which needs to be cleaned up.
Historically, we spawned the Seatbelt and Landlock sandboxes in
substantially different ways:
For **Seatbelt**, we would run `/usr/bin/sandbox-exec` with our policy
specified as an arg followed by the original command:
d1de7bb383/codex-rs/core/src/exec.rs (L147-L219)
For **Landlock/Seccomp**, we would do
`tokio::runtime::Builder::new_current_thread()`, _invoke
Landlock/Seccomp APIs to modify the permissions of that new thread_, and
then spawn the command:
d1de7bb383/codex-rs/core/src/exec_linux.rs (L28-L49)
While it is neat that Landlock/Seccomp supports applying a policy to
only one thread without having to apply it to the entire process, it
requires us to maintain two different codepaths and is a bit harder to
reason about. The tipping point was
https://github.com/openai/codex/pull/1061, in which we had to start
building up the `env` in an unexpected way for the existing
Landlock/Seccomp approach to continue to work.
This PR overhauls things so that we do similar things for Mac and Linux.
It turned out that we were already building our own "helper binary"
comparable to Mac's `sandbox-exec` as part of the `cli` crate:
d1de7bb383/codex-rs/cli/Cargo.toml (L10-L12)
We originally created this to build a small binary to include with the
Node.js version of the Codex CLI to provide support for Linux
sandboxing.
Though the sticky bit is that, at this point, we still want to deploy
the Rust version of Codex as a single, standalone binary rather than a
CLI and a supporting sandboxing binary. To satisfy this goal, we use
"the arg0 trick," in which we:
* use `std::env::current_exe()` to get the path to the CLI that is
currently running
* use the CLI as the `program` for the `Command`
* set `"codex-linux-sandbox"` as arg0 for the `Command`
A CLI that supports sandboxing should check arg0 at the start of the
program. If it is `"codex-linux-sandbox"`, it must invoke
`codex_linux_sandbox::run_main()`, which runs the CLI as if it were
`codex-linux-sandbox`. When acting as `codex-linux-sandbox`, we make the
appropriate Landlock/Seccomp API calls and then use `execvp(3)` to spawn
the original command, so do _replace_ the process rather than spawn a
subprocess. Incidentally, we do this before starting the Tokio runtime,
so the process should only have one thread when `execvp(3)` is called.
Because the `core` crate that needs to spawn the Linux sandboxing is not
a CLI in its own right, this means that every CLI that includes `core`
and relies on this behavior has to (1) implement it and (2) provide the
path to the sandboxing executable. While the path is almost always
`std::env::current_exe()`, we needed to make this configurable for
integration tests, so `Config` now has a `codex_linux_sandbox_exe:
Option<PathBuf>` property to facilitate threading this through,
introduced in https://github.com/openai/codex/pull/1089.
This common pattern is now captured in
`codex_linux_sandbox::run_with_sandbox()` and all of the `main.rs`
functions that should use it have been updated as part of this PR.
The `codex-linux-sandbox` crate added to the Cargo workspace as part of
this PR now has the bulk of the Landlock/Seccomp logic, which makes
`core` a bit simpler. Indeed, `core/src/exec_linux.rs` and
`core/src/landlock.rs` were removed/ported as part of this PR. I also
moved the unit tests for this code into an integration test,
`linux-sandbox/tests/landlock.rs`, in which I use
`env!("CARGO_BIN_EXE_codex-linux-sandbox")` as the value for
`codex_linux_sandbox_exe` since `std::env::current_exe()` is not
appropriate in that case.
