fix: avoid use-after-free in rate_limiter periodic cleanup - #70
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fix: avoid use-after-free in rate_limiter periodic cleanup#70cursor[bot] wants to merge 1 commit into
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check_limit held a reference into std::flat_map requests[key], then erase_if'd empty entries on every 1000th call. flat_map erase invalidates all references, so the following size()/push_back was UAF whenever cleanup removed anything. Record the allow/deny decision before cleanup; add a regression covering the orphan-key path. Co-authored-by: Kaius Ruokonen <ruoka@users.noreply.github.com>
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Bug and impact
http::middleware::rate_limiter::check_limitcould use-after-free on every 1000th call that removed an empty key from itsstd::flat_map. That is undefined behavior in production rate limiting (crash / memory corruption under sustained traffic).Root cause
check_limitheldauto& key_requests = requests[key], then ranstd::erase_ifto drop empty entries.flat_maperase invalidates all references, so the followingsize()/push_backoperated on a dangling reference whenever cleanup removed anything (e.g. an orphan key left bymax_requests == 0).Fix
Record the allow/deny decision and
push_backbeforeerase_if, then return the saved result.Validation
rate_limiter check_limit survives periodic empty-key cleanuptools/CB.sh debug test rate_limiter→ 4/4 passed (1002 assertions)