Michael Bolin
e6c470957d
## Why This PR fixes approval sandbox semantics in the unified-exec path. The zsh-fork runtime exposed the bug because the shell can do meaningful work before any intercepted child `execv(2)` exists: redirections, builtins, globbing, and pipeline setup all happen in the launch process. If the model requested `sandbox_permissions=require_escalated`, or an exec-policy `allow` rule explicitly bypassed the sandbox, that approved sandbox decision needs to be preserved for the launch path and for intercepted execs that use the same approval machinery. The behavior is not only about zsh fork. The production changes are in shared approval/escalation code, so they also affect non-zsh-fork intercepted exec paths that go through the same sandbox decision logic. The narrow intent is to preserve the approval decision while still keeping denied-read profiles and bounded additional-permission requests sandboxed. ## Production Changes - `codex-rs/core/src/tools/runtimes/unified_exec.rs`: derives a `launch_sandbox_permissions` value from the requested sandbox permissions and the runtime filesystem policy, then uses that value for managed-network/env setup and launch sandbox selection. This keeps full approval or policy-bypass decisions visible to the first unified-exec attempt, while still preventing a full sandbox override from discarding denied-read restrictions. Direct unified exec keeps the same decision surface; the important difference is that zsh-fork launch setup no longer accidentally loses the approved parent sandbox decision. - `codex-rs/core/src/tools/runtimes/shell/unix_escalation.rs`: makes intercepted-exec escalation selection explicit for the three sandbox permission modes. `UseDefault` only escalates when an exec-policy decision allows sandbox bypass, `RequireEscalated` escalates when unsandboxed execution is allowed, and `WithAdditionalPermissions` escalates through the bounded additional-permissions path instead of being treated as a full unsandboxed override. Unsandboxed intercepted execs now also rebuild the environment as `RequireEscalated`, which strips managed-network proxy variables consistently with other unsandboxed execution. ## Test Coverage Most of the PR is tests. The new coverage verifies: - unified exec preserves parent approval and exec-policy sandbox decisions for zsh-fork launch selection; - bounded `with_additional_permissions` remains sandboxed and permission-profile based; - denied-read profiles are not weakened by parent approval; - explicit prompt rules still prompt for intercepted execs after the parent command is approved; - unsandboxed intercepted execs strip managed-network env vars. No documentation update is needed; this is an internal approval/sandbox correctness fix. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/openai/codex/pull/24981). * #24982 * __->__ #24981
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 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 bundled codex-resources/bwrap
binary shipped with Codex 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. Legacy read-only and workspace-write policies imply full
filesystem read access; exact readable roots are represented by split
filesystem policies instead.
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
- backend-managed system read roots required for basic execution, such as
C:\Windows,C:\Program Files,C:\Program Files (x86), andC:\ProgramData, when a split filesystem policy requests platform defaults
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.