Hacktoberfest 2026: le issue che i maintainer hanno segnato per ottobre, aperte e adatte ai principianti. Sfoglia le issue Hacktoberfest

HTTP/2 to origin: bodyless response with a header block over 4 KB fails to parse and is sent to the client as 502/500

Chiusa
  • Qualcosa non va?
#13,778 0 commenti 0 reazioni 0 assegnatari Vedi su GitHub

I maintainer di solito rispondono entro 2 giorni

Nessuno ha ancora preso questa issue.

Valutazione

Difficoltà
4/5
Tempo stimato
3-5 giorni
Idoneità per principianti
68/100
Tipo di issue
Bug
Chiarezza
Specificata chiaramente
Stato di attività
Attiva
Stack tecnologico
cpp
Ambito
backend-api-design, networking

Direzione di ricerca

Start with Http2Stream::send_headers and HttpSM::state_read_server_response_header, then follow HTTPHdr::parse_resp in HdrTSOnly.cc and MIMEScanner::get. Reproduce the bodyless HTTP/2 302 or 204 with an approximately 8.8 KB header block. Done means the large header parses across blocks and the client receives the origin response instead of a 502 or 500.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Descrizione

HTTP/2

Summary

If an HTTP/2 origin sends a bodyless response (HEADERS with END_STREAM) whose header block is larger than one IOBuffer block (about 4 KB), ATS fails to parse it. The client gets a 502 or 500 instead of the origin's response. It mostly shows up on redirects and 204s that carry a large Content-Security-Policy or Set-Cookie.

Cause

  1. Http2Stream::send_headers, which hands a received header to the HttpSM, prints the decoded response header into _receive_buffer one block at a time, adding a block whenever print() doesn't finish. A header of more than about 4 KB therefore spans several blocks, and a field can be split at a block boundary.
  2. With receive_end_stream set on an outbound stream, it then signals VC_EVENT_EOS, not READ_READY or READ_COMPLETE.
  3. HttpSM::state_read_server_response_header handles that EOS by parsing with eof = true. It logs Server closed connection while reading response header at this point, even though nothing closed.
  4. HTTPHdr::parse_resp (HdrTSOnly.cc) loops over the reader one block at a time and passes the same eof flag for every block. When a field is cut at the end of the first block, MIMEScanner::get treats it as the end of input and returns ParseResult::ERROR (unterminated field).
  5. The result is handle_server_setup_error, and the client gets an error. squid-style logs show the origin's real status (a 3xx or 204) next to the 5xx sent to the client, with o_bytes stopping just short of the field that crosses the 4 KB boundary.

Observed / reproduction

Reproduced on a 10.0.x build; HdrTSOnly.cc is identical on master.

  • An HTTP/2 origin returns 302 with no body and a header block of about 8.8 KB, including one long Content-Security-Policy field.
  • A GET through ATS: the origin logs a 302, and the client gets a 502 every time, with o_bytes=202 and the request retried once (two attempts).
  • The same responses had no errors while that origin was reached over HTTP/1.1.
  • In production traffic, one bodyless 3xx endpoint failed 150 of 150 requests.

Suggested fix

Either of these, or both:

  • In HTTPHdr::parse_resp, pass eof only for the last block, when there is no further block to read.
  • In Http2Stream, write the whole decoded header into one block sized to fit it, so a header from an HTTP/2 frame is never split.
Lingua principale
C++
Stelle
2k
Fork
878
Merge medio
3g 16h
PR unite (30g)
91

Preparare l'ambiente

Come iniziare

  1. Leggi tutta la issue e poi la guida ai contributi del progetto.
  2. Commenta sulla issue per dire che te ne occupi tu — evita che due persone facciano lo stesso lavoro.
  3. Fai un fork del repository e lavora su un branch.
  4. Apri una pull request che faccia riferimento al numero della issue.

Altre issue di apache/trafficserver

Tutte le issue di apache/trafficserver

Issue simili

Altre issue su C++

Ricevi le nuove issue nella tua casella

Un breve riepilogo di issue GitHub adatte ai principianti.