Files
codex/codex-rs/core
viyatb-oai 6506765168 fix(permissions): preserve managed deny-read during escalation (#15977)
## Why

Managed filesystem `deny_read` requirements are administrator-enforced
restrictions on specific paths. Once those requirements are active,
Codex should not drop them just because an execution path would
otherwise leave the sandbox.

Before this change, an explicit escalation, a prefix-rule allow, a
sandbox-denial retry, or an app-server legacy sandbox override could
rebuild the runtime policy without those managed read-deny entries and
expose a path the administrator had marked unreadable.

This is narrower than general sandbox-mode constraints. If an enterprise
only sets `allowed_sandbox_modes`, a trusted `prefix_rule(..., decision
= "allow")` can still run its matching command unsandboxed; this PR only
preserves managed filesystem `deny_read` restrictions across those
paths.

## What Changed

- Mark filesystem policies built from managed `deny_read` requirements
so callers can tell when those deny entries must survive escalation.
- Preserve managed deny-read entries when runtime permission profiles
are rebuilt through protocol, app-server, or legacy sandbox-policy
compatibility paths.
- Keep managed deny-read attempts inside the selected sandbox on the
first attempt and after sandbox-denial retries.
- Preserve the same behavior in the zsh-fork escalation path, including
prefix-rule-driven escalation.
- Add a regression test showing the opposite case too: without managed
deny-read, a prefix-rule allow still chooses unsandboxed execution.

## Verification

Targeted automated verification:

```shell
cargo test -p codex-core shell_request_escalation_execution_is_explicit -- --nocapture
cargo test -p codex-core prefix_rule_uses_unsandboxed_execution_without_managed_deny_read -- --nocapture
cargo test -p codex-core prefix_rule_preserves_managed_deny_read_escalation -- --nocapture
cargo test -p codex-protocol permission_profile_round_trip_preserves_filesystem_policy_metadata -- --nocapture
cargo test -p codex-protocol preserving_deny_entries_keeps_unrestricted_policy_enforceable -- --nocapture
cargo test -p codex-app-server-protocol permission_profile_file_system_permissions_preserves_policy_metadata -- --nocapture
cargo check -p codex-app-server -p codex-tui
```

Smoke-test invocations:

```shell
# macOS exact deny + allowed control
codex exec --skip-git-repo-check -C "$ROOT" \
  -c 'default_permissions="deny_read_smoke"' \
  -c 'permissions.deny_read_smoke.filesystem={":minimal"="read",":project_roots"={"."="write","secrets"="none","future-secret"="none","**/*.env"="none"}}' \
  'Run shell commands only. Print the contents of allowed.txt. Then test whether reading secrets/exact-secret.txt succeeds without printing that file if it does. End with exactly two lines: allowed=<contents> and exact_secret=<BLOCKED or READABLE>.'

# Linux exact deny + allowed control
codex exec --skip-git-repo-check -C "$ROOT" \
  -c 'default_permissions="deny_read_smoke"' \
  -c 'permissions.deny_read_smoke.filesystem={":minimal"="read",glob_scan_max_depth=3,":project_roots"={"."="write","secrets"="none","future-secret"="none","**/*.env"="none"}}' \
  'Run shell commands only. Print the contents of allowed.txt. Then test whether reading secrets/exact-secret.txt succeeds without printing that file if it does. End with exactly two lines: allowed=<contents> and exact_secret=<BLOCKED or READABLE>.'
```

Observed manual smoke matrix:

| Case | macOS Seatbelt | Linux bubblewrap |
| --- | --- | --- |
| `cat allowed.txt` | Pass | Pass |
| `cat secrets/exact-secret.txt` | Blocked | Blocked |
| `cat envs/root.env` | Blocked | Blocked |
| `cat envs/nested/one.env` | Blocked | Blocked |
| `cat envs/nested/two.env` | Blocked | Blocked |
| `cat alias-to-secrets/exact-secret.txt` | Blocked | Blocked |
| Missing denied path | A file created after sandbox setup remained
unreadable | Creation was blocked by the reserved missing-path
placeholder, and the placeholder was cleaned up after exit |
| Real `codex exec` shell turn | Pass | Pass |

Notes:

- The Linux smoke run used the fallback glob walker because the devbox
did not have `rg` installed.
- The smoke matrix verifies the end-to-end filesystem behavior on macOS
and Linux; the escalation-specific behavior is covered by the focused
tests above.

---------

Co-authored-by: Codex <noreply@openai.com>
Co-authored-by: Charlie Marsh <charliemarsh@openai.com>
2026-05-11 11:49:44 -07:00
..

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 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 ReadOnly and WorkspaceWrite behavior
  • 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), and C:\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.