httpd applies no timeout while receiving a request body, parking a worker on a stalled client

Missing Release of Resource after Effective Lifetime vulnerability in Erlang/OTP inets httpd allows an unauthenticated remote attacker to cause denial of service by sending valid request headers with a large Content-Length and then stalling before the body is complete.

httpd_request_handler:handle_info/2 cancels the request timeout as soon as a parse step succeeds, which includes the headers, and the clause that handles a decoder asking for more data re-arms the socket with {active, once} without setting any further timer. httpd_request:whole_body/2 returns such a continuation whenever the bytes received are fewer than the announced Content-Length, so a well-formed request that stops mid-body leaves the worker waiting indefinitely. The periodic byte-rate check that would reclaim it is armed only when minimum_bytes_per_second is configured, which it is not by default. Repeating this across connections occupies every worker permitted by max_clients and denies service to legitimate clients at negligible bandwidth cost.

This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, OTP 28.5.0.6, and OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, 9.6.2.3, and 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.