From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Wed, 9 Jul 2025 15:30:29 +0000 (+0200)
Subject: BUG/MINOR: h3: fix https scheme request encoding for BE side
X-Git-Tag: v3.3-dev3~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=378c1821929c8d2493642b7c299cce9e424773d9;p=thirdparty%2Fhaproxy.git

BUG/MINOR: h3: fix https scheme request encoding for BE side

An HTTP/3 request must contains :scheme pseudo-header. Currently, only
"https" value is expected due to QUIC transport layer in use.

However, https value is incorrectly encoded due to a QPACK index value
mismatch in qpack_encode_scheme(). Fix it to ensure that scheme is now
properly set for HTTP/3 requests on the backend side.

No need to backport this.
---

diff --git a/src/qpack-enc.c b/src/qpack-enc.c
index 7766bb616..311d2ae20 100644
--- a/src/qpack-enc.c
+++ b/src/qpack-enc.c
@@ -191,10 +191,10 @@ int qpack_encode_scheme(struct buffer *out, const struct ist scheme)
 			b_putchr(out, istptr(scheme)[i]);
 	}
 	else {
-		int idx = 23;
+		const int idx = isteq(scheme, ist("https")) ?
+		  23 : /* :scheme: https */
+		  22;  /* :scheme: http */
 
-		if (unlikely(!isteq(scheme, ist("http"))))
-			idx = 22;
 		if (b_room(out) < 2)
 			return 1;