install: TOCTOU symlink race (unlink-then-create without O_EXCL) allows arbitrary file overwrite
copy_file in install/src/install.rs removes the destination then recreates it by pathname via File::create / fs::copy without O_EXCL/create_new. Between the unlink and the recreate, a local attacker with write access to the destination directory can drop in a symlink and redirect the write. Impact: when install runs privileged into an attacker-writable directory (staging/build paths), the race allows redirecting writes to arbitrary files and overwriting sensitive system files (/etc/passwd, /etc/shadow). Recommendation: create …