codex/codex-rs/shell-escalation/README.md

codex-shell-escalation

This crate contains the Unix shell-escalation protocol implementation and the codex-execve-wrapper executable.

codex-execve-wrapper receives the arguments to an intercepted execve(2) call and delegates the decision to the shell-escalation protocol over a shared file descriptor (specified by the CODEX_ESCALATE_SOCKET environment variable). The server on the other side replies with one of:

• Run: codex-execve-wrapper should invoke execve(2) on itself to run the original command within the sandboxed shell.
• Escalate: forward the file descriptors of the current process so the command can be run faithfully outside the sandbox. When the process completes, the server forwards the exit code back to codex-execve-wrapper.
• Deny: the server has declared the proposed command to be forbidden, so codex-execve-wrapper prints an error to stderr and exits with 1.

Patched Bash

We carry a small patch to execute_cmd.c (see patches/bash-exec-wrapper.patch) that adds support for EXEC_WRAPPER. The original commit message is “add support for BASH_EXEC_WRAPPER” and the patch applies cleanly to a8a1c2fac029404d3f42cd39f5a20f24b6e4fe4b from https://github.com/bminor/bash. To rebuild manually:

git clone https://git.savannah.gnu.org/git/bash
git checkout a8a1c2fac029404d3f42cd39f5a20f24b6e4fe4b
git apply /path/to/patches/bash-exec-wrapper.patch
./configure --without-bash-malloc
make -j"$(nproc)"