## Problem Ubuntu/AppArmor hosts started failing in the default Linux sandbox path after the switch to vendored/default bubblewrap in `0.115.0`. The clearest report is in [#14919](https://github.com/openai/codex/issues/14919), especially [this investigation comment](https://github.com/openai/codex/issues/14919#issuecomment-4076504751): on affected Ubuntu systems, `/usr/bin/bwrap` works, but a copied or vendored `bwrap` binary fails with errors like `bwrap: setting up uid map: Permission denied` or `bwrap: loopback: Failed RTM_NEWADDR: Operation not permitted`. The root cause is Ubuntu's `/etc/apparmor.d/bwrap-userns-restrict` profile, which grants `userns` access specifically to `/usr/bin/bwrap`. Once Codex started using a vendored/internal bubblewrap path, that path was no longer covered by the distro AppArmor exception, so sandbox namespace setup could fail even when user namespaces were otherwise enabled and `uidmap` was installed. ## What this PR changes - prefer system `/usr/bin/bwrap` whenever it is available - keep vendored bubblewrap as the fallback when `/usr/bin/bwrap` is missing - when `/usr/bin/bwrap` is missing, surface a Codex startup warning through the app-server/TUI warning path instead of printing directly from the sandbox helper with `eprintln!` - use the same launcher decision for both the main sandbox execution path and the `/proc` preflight path - document the updated Linux bubblewrap behavior in the Linux sandbox and core READMEs ## Why this fix This still fixes the Ubuntu/AppArmor regression from [#14919](https://github.com/openai/codex/issues/14919), but it keeps the runtime rule simple and platform-agnostic: if the standard system bubblewrap is installed, use it; otherwise fall back to the vendored helper. The warning now follows that same simple rule. If Codex cannot find `/usr/bin/bwrap`, it tells the user that it is falling back to the vendored helper, and it does so through the existing startup warning plumbing that reaches the TUI and app-server instead of low-level sandbox stderr. ## Testing - `cargo test -p codex-linux-sandbox` - `cargo test -p codex-app-server --lib` - `cargo test -p codex-tui-app-server tests::embedded_app_server_start_failure_is_returned` - `cargo clippy -p codex-linux-sandbox --all-targets` - `cargo clippy -p codex-app-server --all-targets` - `cargo clippy -p codex-tui-app-server --all-targets`
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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 supports macOS permission-profile extensions layered on top of
SandboxPolicy:
- no extension profile provided:
keeps legacy default preferences read access (
user-preference-read). - extension profile provided with no
macos_preferencesgrant: does not add preferences access clauses. macos_preferences = "readonly": enables cfprefs read clauses anduser-preference-read.macos_preferences = "readwrite": includes readonly clauses plususer-preference-writeand cfprefs shm write clauses.macos_automation = true: enables broad Apple Events send permissions.macos_automation = ["com.apple.Notes", ...]: enables Apple Events send only to listed bundle IDs.macos_launch_services = true: enables LaunchServices lookups and open/launch operations.macos_accessibility = true: enablescom.apple.axservermach lookup.macos_calendar = true: enablescom.apple.CalendarAgentmach lookup.macos_contacts = "read_only": enables Address Book read access and Contacts read services.macos_contacts = "read_write": includes the readonly Contacts clauses plus Address Book writes and keychain/temp helpers required for writes.
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 /usr/bin/bwrap whenever it is available and
falls back to the vendored bubblewrap path otherwise. When /usr/bin/bwrap is
missing, Codex also surfaces a startup warning through its normal notification
path instead of printing directly from the sandbox helper.
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.