fix: TOCTOU race in mktemp_portable fallback#38
Merged
Neo23x0 merged 1 commit intoNextronSystems:script-robustnessfrom Mar 17, 2026
Merged
fix: TOCTOU race in mktemp_portable fallback#38Neo23x0 merged 1 commit intoNextronSystems:script-robustnessfrom
Neo23x0 merged 1 commit intoNextronSystems:script-robustnessfrom
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When mktemp is unavailable, the fallback now creates a private directory first (mkdir is atomic with umask 077), then creates temp files inside it. This eliminates the race window where an attacker could predict the filename and pre-create a symlink in /tmp. Cleanup updated to remove the fallback directory on exit.
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When
mktempis unavailable, the fallback path previously created a predictable filename (thunderstorm.$$.$RANDOM) and wrote to it non-atomically. An attacker could predict the name and pre-create a symlink.Fix: Create a private directory first (
mkdiris atomic), then create temp files inside it. Cleanup updated to remove the fallback directory on exit.Found by Axiom-Loop (GLM-5 + Kimi K2.5 flagged independently).