From: Christopher Faulet <cfaulet@haproxy.com>
Date: Wed, 5 Feb 2025 14:06:45 +0000 (+0100)
Subject: BUG/MEDIUM: mux-fcgi: Propagate flags to SE in fcgi_strm_wake_one_stream
X-Git-Tag: v3.2-dev5~21
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5b1c2277ae61c161baed8182ad5416714a62272f;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: mux-fcgi: Propagate flags to SE in fcgi_strm_wake_one_stream

The commit is flagged as a bug because the same fix on the H2 multiplexer was
reported as a bug. But no issue was reported.

When a stream is explicitly woken up by the FCGI conneciton, if an error
condition is detected, the corresponding error flag is set on the SE. So
SE_FL_ERROR or SE_FL_ERR_PENDING, depending if the end of stream was
reported or not.

However, there is no attempt to propagate other termination flags. We must
be sure to properly set SE_FL_EOI and SE_FL_EOS when appropriate to be able
to switch a pending error to a fatal error.

Because of this bug, the SE could remain with a pending error and no end of
stream, preventing the applicative stream to trully abort it. It means on
some abort scenario, it seems to be possible to block a stream infinitely.

This patche depends on:

  * MEDIUM: mux-fcgi: Add a function to propagate termination flags from fstrm to SE
  * BUG/MEDIUM: mux-fcgi: Properly handle read0 on partial records

This patch could be backported at least as far as 2.8 after a period of
observation. However no bug was reportedn so there is no rush.
---

diff --git a/src/mux_fcgi.c b/src/mux_fcgi.c
index bd6efc20e..7a8ceef5b 100644
--- a/src/mux_fcgi.c
+++ b/src/mux_fcgi.c
@@ -1110,7 +1110,7 @@ static void fcgi_strm_wake_one_stream(struct fcgi_strm *fstrm)
 
 	if (fconn->state == FCGI_CS_CLOSED || (fconn->flags & (FCGI_CF_ERR_PENDING|FCGI_CF_ERROR))) {
 		se_fl_set_error(fstrm->sd);
-
+		fcgi_strm_propagate_term_flags(fconn, fstrm);
 		if (fstrm->state < FCGI_SS_ERROR) {
 			fstrm->state = FCGI_SS_ERROR;
 			TRACE_STATE("switching to ERROR", FCGI_EV_STRM_WAKE|FCGI_EV_FSTRM_END, fconn->conn, fstrm);