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20 Commits
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cli: infer host sandbox backend (#24102)
## Why `codex sandbox` previously required an OS subcommand like `linux`, `macos`, or `windows`, even though the command can only run the sandbox backend available on the current host. That made the CLI imply a cross-OS choice that does not exist. ## What changed - Collapse `codex sandbox <os>` into `codex sandbox [COMMAND]...` by wiring the `sandbox` parser directly to the host-specific backend args with `cfg`. - Keep the existing backend runners for Seatbelt, Linux sandbox, and Windows restricted token. - Rename the public Windows debug sandbox runner to `run_command_under_windows_sandbox` for clarity. - Update the Rust sandbox docs and related README references to describe host OS selection and avoid pointing readers at legacy `sandbox_mode` config. ## Arg0 compatibility The `codex-linux-sandbox` helper path is still handled before normal CLI parsing. `arg0_dispatch()` checks whether the executable basename is `codex-linux-sandbox` and directly calls `codex_linux_sandbox::run_main()`, so removing the `sandbox linux` parser branch does not affect the arg0 helper flow. ## Verification - `cargo test -p codex-cli` - `cargo test -p codex-arg0` - `just fix -p codex-cli`
Michael Bolin ·
2026-05-22 10:23:59 -07:00 -
permissions: canonicalize workspace_roots and danger-full-access names (#22624)
## Why This is a small precursor to the larger permissions-migration work. Both the comparison stack in [#22401](https://github.com/openai/codex/pull/22401) / [#22402](https://github.com/openai/codex/pull/22402) and the alternate stack in [#22610](https://github.com/openai/codex/pull/22610) / [#22611](https://github.com/openai/codex/pull/22611) / [#22612](https://github.com/openai/codex/pull/22612) are easier to review if the terminology is already settled underneath them. Because `:project_roots` and `:danger-no-sandbox` have not shipped as stable user-facing surface area, carrying them forward as aliases would just add more migration logic to the later stacks. This PR removes that ambiguity now so the follow-on work can rely on one spelling for each built-in concept. ## What Changed - renamed the config-facing special filesystem key from `:project_roots` to `:workspace_roots` - dropped unpublished `:project_roots` parsing support in `core/src/config/permissions.rs`, so new config only recognizes `:workspace_roots` - renamed the built-in full-access permission profile id from `:danger-no-sandbox` to `:danger-full-access` - dropped unpublished `:danger-no-sandbox` support entirely, including the old active-profile canonicalization path, and added explicit rejection coverage for the legacy id - introduced shared built-in permission-profile id constants in `codex-rs/protocol/src/models.rs` - updated `core`, `app-server`, and `tui` call sites that special-case built-in profiles to use the shared constants and canonical ids - updated tests and the Linux sandbox README to use `:workspace_roots` / `:danger-full-access` ## Verification I focused verification on the three places this rename can regress: config parsing, active-profile identity surfaced back out of `core`, and user/server call sites that special-case built-in profiles. Targeted checks: - `config::tests::default_permissions_can_select_builtin_profile_without_permissions_table` - `config::tests::default_permissions_read_only_applies_additional_writable_roots_as_modifications` - `config::tests::default_permissions_can_select_builtin_full_access_profile` - `config::tests::legacy_danger_no_sandbox_is_rejected` - `workspace_root` filtered `codex-core` tests - `request_processors::thread_processor::thread_processor_tests::thread_processor_behavior_tests::requested_permissions_trust_project_uses_permission_profile_intent` - `suite::v2::turn_start::turn_start_rejects_invalid_permission_selection_before_starting_turn` - `status::tests::status_snapshot_shows_auto_review_permissions` - `status::tests::status_permissions_full_disk_managed_with_network_is_danger_full_access` - `app_server_session::tests::embedded_turn_permissions_use_active_profile_selection`
Michael Bolin ·
2026-05-14 08:45:54 -07:00 -
linux-sandbox: use standalone bundled bwrap (#21255)
**Summary** - Add `codex-bwrap`, a standalone `bwrap` binary built from the existing vendored bubblewrap sources. - Remove the linked vendored bwrap path from `codex-linux-sandbox`; runtime now prefers system `bwrap` and falls back to bundled `codex-resources/bwrap`. - Add bundled SHA-256 verification with missing/all-zero digest as the dev-mode skip value, then exec the verified file through `/proc/self/fd`. - Keep `launcher.rs` focused on choosing and dispatching the preferred launcher. Bundled lookup, digest verification, and bundled exec now live in `linux-sandbox/src/bundled_bwrap.rs`; Bazel runfiles lookup lives in `linux-sandbox/src/bazel_bwrap.rs`; shared argv/fd exec helpers live in `linux-sandbox/src/exec_util.rs`. - Teach Bazel tests to surface the Bazel-built `//codex-rs/bwrap:bwrap` through `CARGO_BIN_EXE_bwrap`; `codex-linux-sandbox` only honors that fallback in debug Bazel runfiles environments so release/user runtime lookup stays tied to `codex-resources/bwrap`. - Allow `codex-exec-server` filesystem helpers to preserve just the Bazel bwrap/runfiles variables they need in debug Bazel builds, since those helpers intentionally rebuild a small environment before spawning `codex-linux-sandbox`. - Verify the Bazel bwrap target in Linux release CI with a build-only check. Running `bwrap --version` is too strong for GitHub runners because bubblewrap still attempts namespace setup there. **Verification** - Latest update: `cargo test -p codex-linux-sandbox` - Latest update: `just fix -p codex-linux-sandbox` - `cargo check --target x86_64-unknown-linux-gnu -p codex-linux-sandbox` could not run locally because this macOS machine does not have `x86_64-linux-gnu-gcc`; GitHub Linux Bazel CI is expected to cover the Linux-only modules. - Earlier in this PR: `cargo test -p codex-bwrap` - Earlier in this PR: `cargo test -p codex-exec-server` - Earlier in this PR: `cargo check --release -p codex-exec-server` - Earlier in this PR: `just fix -p codex-linux-sandbox -p codex-exec-server` - Earlier in this PR: `bazel test --nobuild //codex-rs/linux-sandbox:linux-sandbox-all-test //codex-rs/core:core-all-test //codex-rs/exec-server:exec-server-file_system-test //codex-rs/app-server:app-server-all-test` (analysis completed; Bazel then refuses to run tests under `--nobuild`) - Earlier in this PR: `bazel build --nobuild //codex-rs/bwrap:bwrap` - Prior to this update: `just bazel-lock-update`, `just bazel-lock-check`, and YAML parse check for `.github/workflows/bazel.yml` --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/openai/codex/pull/21255). * #21257 * #21256 * __->__ #21255
Michael Bolin ·
2026-05-05 17:14:29 -07:00 -
feat(sandbox): add glob deny-read platform enforcement (#18096)
## Summary - adds macOS Seatbelt deny rules for unreadable glob patterns - expands unreadable glob matches on Linux and masks them in bwrap, including canonical symlink targets - keeps Linux glob expansion robust when `rg` is unavailable in minimal or Bazel test environments - adds sandbox integration coverage that runs `shell` and `exec_command` with a `**/*.env = none` policy and verifies the secret contents do not reach the model ## Linux glob expansion ```text Prefer: rg --files --hidden --no-ignore --glob <pattern> -- <search-root> Fallback: internal globset walker when rg is not installed Failure: any other rg failure aborts sandbox construction ``` ``` [permissions.workspace.filesystem] glob_scan_max_depth = 2 [permissions.workspace.filesystem.":project_roots"] "**/*.env" = "none" ``` This keeps the common path fast without making sandbox construction depend on an ambient `rg` binary. If `rg` is present but fails for another reason, the sandbox setup fails closed instead of silently omitting deny-read masks. ## Platform support - macOS: subprocess sandbox enforcement is handled by Seatbelt regex deny rules - Linux: subprocess sandbox enforcement is handled by expanding existing glob matches and masking them in bwrap - Windows: policy/config/direct-tool glob support is already on `main` from #15979; Windows subprocess sandbox paths continue to fail closed when unreadable split filesystem carveouts require runtime enforcement, rather than silently running unsandboxed ## Stack 1. #15979 - merged: cross-platform glob deny-read policy/config/direct-tool support for macOS, Linux, and Windows 2. This PR - macOS/Linux subprocess sandbox enforcement plus Windows fail-closed clarification 3. #17740 - managed deny-read requirements ## Verification - Added integration coverage for `shell` and `exec_command` glob deny-read enforcement - `cargo check -p codex-sandboxing -p codex-linux-sandbox --tests` - `cargo check -p codex-core --test all` - `cargo clippy -p codex-linux-sandbox -p codex-sandboxing --tests` - `just bazel-lock-check` --------- Co-authored-by: Codex <noreply@openai.com>
viyatb-oai ·
2026-04-16 17:35:16 -07:00 -
fix(sandboxing): reject WSL1 bubblewrap sandboxing (#17559)
## Summary - detect WSL1 before Codex probes or invokes the Linux bubblewrap sandbox - fail early with a clear unsupported-operation message when a command would require bubblewrap on WSL1 - document that WSL2 follows the normal Linux bubblewrap path while WSL1 is unsupported ## Why Codex 0.115.0 made bubblewrap the default Linux sandbox. WSL1 cannot create the user namespaces that bubblewrap needs, so shell commands currently fail later with a raw bwrap namespace error. This makes the unsupported environment explicit and keeps non-bubblewrap paths unchanged. The WSL detection reads /proc/version, lets an explicit WSL<version> marker decide WSL1 vs WSL2+, and only treats a bare Microsoft marker as WSL1 when no explicit WSL version is present. addresses https://github.com/openai/codex/issues/16076 --------- Co-authored-by: Codex <noreply@openai.com>
viyatb-oai ·
2026-04-12 14:08:14 -07:00 -
fix: warn when bwrap cannot create user namespaces (#15893)
## Summary - add a Linux startup warning when system `bwrap` is present but cannot create user namespaces - keep the Linux-specific probe, sandbox-policy gate, and stderr matching in `codex-sandboxing` - polish the missing-`bwrap` warning to point users at the sandbox prerequisites and OS package-manager install path ## Details - probes system `bwrap` with `--unshare-user`, `--unshare-net`, and a minimal bind before command execution - detects known bubblewrap setup failures for `RTM_NEWADDR`, `RTM_NEWLINK`, uid-map permission denial, and `No permissions to create a new namespace` - preserves the existing suppression for sandbox-bypassed policies such as `danger-full-access` and `external-sandbox` - updates the Linux sandbox docs to call out the user-namespace requirement --------- Co-authored-by: Codex <noreply@openai.com>
viyatb-oai ·
2026-04-06 19:19:35 -07:00 -
fix: resolve bwrap from trusted PATH entry (#15791)
## Summary - resolve system bwrap from PATH instead of hardcoding /usr/bin/bwrap - skip PATH entries that resolve inside the current workspace before launching the sandbox helper - keep the vendored bubblewrap fallback when no trusted system bwrap is found ## Validation - cargo test -p codex-core bwrap --lib - cargo test -p codex-linux-sandbox - just fix -p codex-core - just fix -p codex-linux-sandbox - just fmt - just argument-comment-lint - cargo clean
viyatb-oai ·
2026-03-26 12:13:51 -07:00 -
fix: fix old system bubblewrap compatibility without falling back to vendored bwrap (#15693)
Fixes #15283. ## Summary Older system bubblewrap builds reject `--argv0`, which makes our Linux sandbox fail before the helper can re-exec. This PR keeps using system `/usr/bin/bwrap` whenever it exists and only falls back to vendored bwrap when the system binary is missing. That matters on stricter AppArmor hosts, where the distro bwrap package also provides the policy setup needed for user namespaces. For old system bwrap, we avoid `--argv0` instead of switching binaries: - pass the sandbox helper a full-path `argv0`, - keep the existing `current_exe() + --argv0` path when the selected launcher supports it, - otherwise omit `--argv0` and re-exec through the helper's own `argv[0]` path, whose basename still dispatches as `codex-linux-sandbox`. Also updates the launcher/warning tests and docs so they match the new behavior: present-but-old system bwrap uses the compatibility path, and only absent system bwrap falls back to vendored. ### Validation 1. Install Ubuntu 20.04 in a VM 2. Compile codex and run without bubblewrap installed - see a warning about falling back to the vendored bwrap 3. Install bwrap and verify version is 0.4.0 without `argv0` support 4. run codex and use apply_patch tool without errors <img width="802" height="631" alt="Screenshot 2026-03-25 at 11 48 36 PM" src="https://github.com/user-attachments/assets/77248a29-aa38-4d7c-9833-496ec6a458b8" /> <img width="807" height="634" alt="Screenshot 2026-03-25 at 11 47 32 PM" src="https://github.com/user-attachments/assets/5af8b850-a466-489b-95a6-455b76b5050f" /> <img width="812" height="635" alt="Screenshot 2026-03-25 at 11 45 45 PM" src="https://github.com/user-attachments/assets/438074f0-8435-4274-a667-332efdd5cb57" /> <img width="801" height="623" alt="Screenshot 2026-03-25 at 11 43 56 PM" src="https://github.com/user-attachments/assets/0dc8d3f5-e8cf-4218-b4b4-a4f7d9bf02e3" /> --------- Co-authored-by: Michael Bolin <mbolin@openai.com>
viyatb-oai ·
2026-03-25 23:51:39 -07:00 -
fix: fall back to vendored bubblewrap when system bwrap lacks --argv0 (#15338)
## Why Fixes [#15283](https://github.com/openai/codex/issues/15283), where sandboxed tool calls fail on older distro `bubblewrap` builds because `/usr/bin/bwrap` does not understand `--argv0`. The upstream [bubblewrap v0.9.0 release notes](https://github.com/containers/bubblewrap/releases/tag/v0.9.0) explicitly call out `Add --argv0`. Flipping `use_legacy_landlock` globally works around that compatibility bug, but it also weakens the default Linux sandbox and breaks proxy-routed and split-policy cases called out in review. The follow-up Linux CI failure was in the new launcher test rather than the launcher logic: the fake `bwrap` helper stayed open for writing, so Linux would not exec it. This update also closes the user-visibility gap from review by surfacing the same startup warning when `/usr/bin/bwrap` is present but too old for `--argv0`, not only when it is missing. ## What Changed - keep `use_legacy_landlock` default-disabled - teach `codex-rs/linux-sandbox/src/launcher.rs` to fall back to the vendored bubblewrap build when `/usr/bin/bwrap` does not advertise `--argv0` support - add launcher tests for supported, unsupported, and missing system `bwrap` - write the fake `bwrap` test helper to a closed temp path so the supported-path launcher test works on Linux too - extend the startup warning path so Codex warns when `/usr/bin/bwrap` is missing or too old to support `--argv0` - mirror the warning/fallback wording across `codex-rs/linux-sandbox/README.md` and `codex-rs/core/README.md`, including that the fallback is the vendored bubblewrap compiled into the binary - cite the upstream `bubblewrap` release that introduced `--argv0` ## Verification - `bazel test --config=remote --platforms=//:rbe //codex-rs/linux-sandbox:linux-sandbox-unit-tests --test_filter=launcher::tests::prefers_system_bwrap_when_help_lists_argv0 --test_output=errors` - `cargo test -p codex-core system_bwrap_warning` - `cargo check -p codex-exec -p codex-tui -p codex-tui-app-server -p codex-app-server` - `just argument-comment-lint`
Michael Bolin ·
2026-03-23 09:46:51 -07:00 -
fix(linux-sandbox): prefer system /usr/bin/bwrap when available (#14963)
## 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`
viyatb-oai ·
2026-03-17 23:05:34 +00:00 -
fix: reopen writable linux carveouts under denied parents (#14514)
## Summary - preserve Linux bubblewrap semantics for `write -> none -> write` filesystem policies by recreating masked mount targets before rebinding narrower writable descendants - add a Linux runtime regression for `/repo = write`, `/repo/a = none`, `/repo/a/b = write` so the nested writable child is exercised under bubblewrap - document the supported legacy Landlock fallback and the split-policy bubblewrap behavior for overlapping carveouts ## Example Given a split filesystem policy like: ```toml "/repo" = "write" "/repo/a" = "none" "/repo/a/b" = "write" ``` this PR keeps `/repo` writable, masks `/repo/a`, and still reopens `/repo/a/b` as writable again under bubblewrap. ## Testing - `just fmt` - `cargo test -p codex-linux-sandbox` - `cargo clippy -p codex-linux-sandbox --tests -- -D warnings`
viyatb-oai ·
2026-03-13 01:36:06 +00:00 -
fix: preserve split filesystem semantics in linux sandbox (#14173)
## 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.
viyatb-oai ·
2026-03-12 10:56:32 -07:00 -
refactor: make bubblewrap the default Linux sandbox (#13996)
## 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
viyatb-oai ·
2026-03-11 23:31:18 -07:00 -
fix(linux-sandbox): always unshare bwrap userns (#13624)
## Summary - always pass `--unshare-user` in the Linux bubblewrap argv builders - stop relying on bubblewrap's auto-userns behavior, which is skipped for `uid 0` - update argv expectations in tests and document the explicit user namespace behavior The installed Codex binary reproduced the same issue with: - `codex -c features.use_linux_sandbox_bwrap=true sandbox linux -- true` - `bwrap: Creating new namespace failed: Operation not permitted` This happens because Codex asked bubblewrap for mount/pid/network namespaces without explicitly asking for a user namespace. In a root-inside-container environment without ambient `CAP_SYS_ADMIN`, that fails. Adding `--unshare-user` makes bubblewrap create the user namespace first and then the remaining namespaces succeed.
viyatb-oai ·
2026-03-05 21:57:40 +00:00 -
feat(linux-sandbox): implement proxy-only egress via TCP-UDS-TCP bridge (#11293)
## Summary - Implement Linux proxy-only routing in `codex-rs/linux-sandbox` with a two-stage bridge: host namespace `loopback TCP proxy endpoint -> UDS`, then bwrap netns `loopback TCP listener -> host UDS`. - Add hidden `--proxy-route-spec` plumbing for outer-to-inner stage handoff. - Fail closed in proxy mode when no valid loopback proxy endpoints can be routed. - Introduce explicit network seccomp modes: `Restricted` (legacy restricted networking) and `ProxyRouted` (allow INET/INET6 for routed proxy access, deny `AF_UNIX` and `socketpair`). - Enforce that proxy bridge/routing is bwrap-only by validating `--apply-seccomp-then-exec` requires `--use-bwrap-sandbox`. - Keep landlock-only flows unchanged (no proxy bridge behavior outside bwrap). --------- Co-authored-by: Codex <199175422+chatgpt-codex-connector[bot]@users.noreply.github.com>
viyatb-oai ·
2026-02-21 18:16:34 +00:00 -
feat(sandbox): enforce proxy-aware network routing in sandbox (#11113)
## Summary - expand proxy env injection to cover common tool env vars (`HTTP_PROXY`/`HTTPS_PROXY`/`ALL_PROXY`/`NO_PROXY` families + tool-specific variants) - harden macOS Seatbelt network policy generation to route through inferred loopback proxy endpoints and fail closed when proxy env is malformed - thread proxy-aware Linux sandbox flags and add minimal bwrap netns isolation hook for restricted non-proxy runs - add/refresh tests for proxy env wiring, Seatbelt policy generation, and Linux sandbox argument wiring
viyatb-oai ·
2026-02-10 07:44:21 +00:00 -
feat(linux-sandbox): add bwrap support (#9938)
## 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.
viyatb-oai ·
2026-02-04 11:13:17 -08:00 -
revert: remove pre-Landlock bind mounts apply (#9300)
**Description** This removes the pre‑Landlock read‑only bind‑mount step from the Linux sandbox so filesystem restrictions rely solely on Landlock again. `mounts.rs` is kept in place but left unused. The linux‑sandbox README is updated to match the new behavior and manual test expectations.
viyatb-oai ·
2026-01-15 09:47:57 -08:00 -
feat: add support for read-only bind mounts in the linux sandbox (#9112)
### Motivation - Landlock alone cannot prevent writes to sensitive in-repo files like `.git/` when the repo root is writable, so explicit mount restrictions are required for those paths. - The sandbox must set up any mounts before calling Landlock so Landlock can still be applied afterwards and the two mechanisms compose correctly. ### Description - Add a new `linux-sandbox` helper `apply_read_only_mounts` in `linux-sandbox/src/mounts.rs` that: unshares namespaces, maps uids/gids when required, makes mounts private, bind-mounts targets, and remounts them read-only. - Wire the mount step into the sandbox flow by calling `apply_read_only_mounts(...)` before network/seccomp and before applying Landlock rules in `linux-sandbox/src/landlock.rs`.
viyatb-oai ·
2026-01-14 08:30:46 -08:00 -
fix: overhaul how we spawn commands under seccomp/landlock on Linux (#1086)
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: https://github.com/openai/codex/blob/d1de7bb383552e8fadd94be79d65d188e00fd562/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: https://github.com/openai/codex/blob/d1de7bb383552e8fadd94be79d65d188e00fd562/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: https://github.com/openai/codex/blob/d1de7bb383552e8fadd94be79d65d188e00fd562/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.
Michael Bolin ·
2025-05-23 11:37:07 -07:00