fix(query-normalize): make ERROR_SIGNAL genuinely linear-time (ReDoS hardening)#8
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The leading-identifier run `[\w$]*` before the Error/Exception/Warning
suffix was unbounded, so a long suffix-less word run forced O(n^2)
backtracking from every offset (~21s at 200K chars) — contradicting the
file's own "linear, ReDoS-safe" header. Live exposure was bounded by the
4000-char prompt cap (~10ms), so this was a false-guarantee / correctness
issue, not an exploitable hang. Bound the run to {0,64} (real exception
names are far shorter) → linear; 200K worst case now <100ms.
Also corrects the header claim and adds a smoke test that feeds a single
200K-char suffix-less token under a wall-clock bound — the prior
frame-flood test used short lines and never reached the quadratic path,
so the linear-time claim was asserted but untested.
Found by the post-merge adversarial review of #7.
298 tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Follow-up to #7, found by the post-merge adversarial review.
lib/query-normalize.js'sERROR_SIGNALhad an unbounded leading-identifierrun (
[\w$]*) before theError|Exception|Warningsuffix. On a longsuffix-less word run that forced O(n²) backtracking from every start offset
(~21s at 200K chars) — directly contradicting the file header's "linear,
ReDoS-safe by construction" claim.
Not exploitable today: the UserPromptSubmit hook caps prompts at 4000 chars
before the de-noiser runs (~10ms worst case), so fail-open held. But the lib is
exported uncapped and carried a false guarantee, and the existing "frame-flood"
test used short repeated lines that never reach the quadratic path.
Fix: bound the run to
{0,64}(real exception names are far shorter) → linear.200K worst case drops from ~21s to <100ms. Header claim corrected to "bounded
quantifiers / linear". New smoke test feeds a single 200K-char suffix-less token
under a wall-clock bound, plus a parity-at-scale check.
298 tests green (smoke 168). The decay-escalation kernel from #7 was separately
fuzzed (200k iterations) and confirmed clean — OPEN→PAUSE-only ceiling holds.
🤖 Generated with Claude Code