dae0608c06
## Summary
- adds managed requirements support for deny-read filesystem entries
- constrains config layers so managed deny-read requirements cannot be
widened by user-controlled config
- surfaces managed deny-read requirements through debug/config plumbing
This PR lets managed requirements inject deny-read filesystem
constraints into the effective filesystem sandbox policy.
User-controlled config can still choose the surrounding permission
profile, but it cannot remove or weaken the managed deny-read entries.
## Managed deny-read shape
A managed requirements file can declare exact paths and glob patterns
under `[permissions.filesystem]`:
```toml
# /etc/codex/requirements.toml
[permissions.filesystem]
deny_read = [
"/Users/alice/.gitconfig",
"/Users/alice/.ssh",
"./managed-private/**/*.env",
]
```
Those entries are compiled into the effective filesystem policy as
`access = none` rules, equivalent in shape to filesystem permission
entries like:
```toml
[permissions.workspace.filesystem]
"/Users/alice/.gitconfig" = "none"
"/Users/alice/.ssh" = "none"
"/absolute/path/to/managed-private/**/*.env" = "none"
```
The important difference is that the managed entries come from
requirements, so lower-precedence user config cannot remove them or make
those paths readable again.
Relative managed `deny_read` entries are resolved relative to the
directory containing the managed requirements file. Glob entries keep
their glob suffix after the non-glob prefix is normalized.
## Runtime behavior
- Managed `deny_read` entries are appended to the effective
`FileSystemSandboxPolicy` after the selected permission profile is
resolved.
- Exact paths become `FileSystemPath::Path { access: None }`; glob
patterns become `FileSystemPath::GlobPattern { access: None }`.
- When managed deny-read entries are present, `sandbox_mode` is
constrained to `read-only` or `workspace-write`; `danger-full-access`
and `external-sandbox` cannot silently bypass the managed read-deny
policy.
- On Windows, the managed deny-read policy is enforced for direct file
tools, but shell subprocess reads are not sandboxed yet, so startup
emits a warning for that platform.
- `/debug-config` shows the effective managed requirement as
`permissions.filesystem.deny_read` with its source.
## Stack
1. #15979 - glob deny-read policy/config/direct-tool support
2. #18096 - macOS and Linux sandbox enforcement
3. This PR - managed deny-read requirements
---------
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. 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.