From: Willy Tarreau <w@1wt.eu>
Date: Fri, 5 Feb 2021 10:41:46 +0000 (+0100)
Subject: BUG/MEDIUM: mux-h2: handle remaining read0 cases
X-Git-Tag: v2.4-dev7~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f09612289;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: mux-h2: handle remaining read0 cases

Commit 3d4631fec ("BUG/MEDIUM: mux-h2: fix read0 handling on partial
frames") tried to address an issue introduced in commit aade4edc1 where
read0 wasn't properly handled in the middle of a frame. But the fix was
incomplete for two reasons:

  - first, it would set H2_CF_RCVD_SHUT in h2_recv() after detecting
    a read0 but the condition was guarded by h2_recv_allowed() which
    explicitly excludes read0 ;

  - second, h2_process would only call h2_process_demux() when there
    were still data in the buffer, but closing after a short pause to
    leave a buffer empty wouldn't be caught in this case.

This patch fixes this by properly taking care of the received shutdown
and by also waking up h2_process_demux() on an empty buffer if the demux
is not blocked.

Given the patches above were tagged for backporting to 2.0, this one
should be as well.
---

diff --git a/src/mux_h2.c b/src/mux_h2.c
index 511975bd9c..c6425164de 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -3634,11 +3634,11 @@ static int h2_recv(struct h2c *h2c)
 
 	ret = max ? conn->xprt->rcv_buf(conn, conn->xprt_ctx, buf, max, 0) : 0;
 
-	if (max && !ret && h2_recv_allowed(h2c)) {
+	if (max && !ret) {
 		if (conn_xprt_read0_pending(h2c->conn)) {
 			TRACE_DATA("received read0", H2_EV_H2C_RECV, h2c->conn);
 			h2c->flags |= H2_CF_RCVD_SHUT;
-		} else {
+		} else if (h2_recv_allowed(h2c)) {
 			TRACE_DATA("failed to receive data, subscribing", H2_EV_H2C_RECV, h2c->conn);
 			conn->xprt->subscribe(conn, conn->xprt_ctx, SUB_RETRY_RECV, &h2c->wait_event);
 		}
@@ -3843,7 +3843,8 @@ static int h2_process(struct h2c *h2c)
 
 	TRACE_ENTER(H2_EV_H2C_WAKE, conn);
 
-	if (b_data(&h2c->dbuf) && !(h2c->flags & H2_CF_DEM_BLOCK_ANY)) {
+	if (!(h2c->flags & H2_CF_DEM_BLOCK_ANY) &&
+	    (b_data(&h2c->dbuf) || (h2c->flags & H2_CF_RCVD_SHUT))) {
 		h2_process_demux(h2c);
 
 		if (h2c->st0 >= H2_CS_ERROR || conn->flags & CO_FL_ERROR)