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Fix quadratic ReDoS in Unix-timestamp format token X - #1356
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jaideeppyne wants to merge 1 commit into
Open
jaideeppyne wants to merge 1 commit into
jaideeppyne wants to merge 1 commit into
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The previous _TIMESTAMP_RE used two adjacent unbounded \d+ groups separated by an optional dot, which backtracks quadratically on digit-heavy non-matches such as "9"*N + "x". Make the fractional part a single optional non-capturing group so matching is linear, while still accepting integers, decimals, and negative timestamps.
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #1356 +/- ##
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Coverage 100.00% 100.00%
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Files 10 10
Lines 2315 2315
Branches 358 358
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Problem
arrow.get(string, "X")used_TIMESTAMP_RE = re.compile(r"^\-?\d+\.?\d+$"). The two adjacent unbounded\d+groups separated by an optional.backtrack quadratically on digit-heavy non-matching input such as"9"*N + "x". A 40 KB payload could block a worker for ~15s.Fix
Rewrite the regex so the fractional part is a single optional group:
This is linear in the input length and still accepts integers, decimals, and negative timestamps.
Tests
"9"*40000 + "x") to confirm it fails quickly.Fixes #1353