EnvAllowListScrub's blanking loop splices each name into a string
handed to eval ("export ${n}="). That is only safe because every name
reaching _cb633_blank already passed an identifier check in the
enumeration loop -- 20 lines away, in a different loop. Before eval
was introduced a non-conforming name reaching plain `export "$n="`
was inert either way (the quoting neutralized it); eval removed that
safety net, so the enumeration loop's guard became the ONLY thing
standing between a non-identifier string and code execution in the
member's pane, with nothing at the eval site itself defending that
property.
Re-assert the same [A-Za-z_][A-Za-z0-9_]* check immediately before
the eval call, independent of the enumeration loop's own guard (left
untouched, not moved). A name that fails it is counted unblankable
rather than silently dropped, so a bypass of the upstream guard would
leave real evidence in the report.
New test exploits the "junk from multi-line values" gap the
enumeration loop's own comment already documents: a value with an
embedded newline makes `command env`'s text output split into a
spurious extra "name" line that was never a real variable. Runs the
real generated scrubScript() end-to-end under zsh and asserts the
non-conforming fragment is neither blanked nor counted unblankable.
The fragment used is merely non-conforming (contains a dot) --
never command-shaped.
Mutation-verified both guards. Weakening the enumeration guard alone
DOES break the new test (the fragment then reaches the new eval-site
guard and gets counted unblankable, failing the "not unblankable"
assertion). Removing the new eval-site guard alone, with the
enumeration guard intact, does NOT break it: _cb633_blank has exactly
one producer (the enumeration loop), so nothing can reach the eval
site without already having passed the identical check there. That is
expected given the single-source architecture, and it is exactly why
the eval-site guard is defense-in-depth against a future change that
adds a second path into _cb633_blank or decouples the two loops --
not a currently independently-observable divergence.
Dai Ha
5c08054533