From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Wed, 16 Apr 2025 15:29:41 +0000 (+0200)
Subject: BUG/MEDIUM: h3: trim whitespaces in header value prior to QPACK encoding
X-Git-Tag: v3.2-dev11~45
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bd3587574dae43cc019d8e9998e0996c75550de4;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: h3: trim whitespaces in header value prior to QPACK encoding

This commit does a similar job than the previous one, but it acts now on
the response path. Any leading or trailing whitespaces characters from a
HTX block header value are removed, prior to the header encoding via
QPACK.

This must be backported up to 2.6.
---

diff --git a/src/h3.c b/src/h3.c
index 9b0c8ad4d..f1b3ec7c5 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -1565,6 +1565,29 @@ static int h3_control_send(struct qcs *qcs, void *ctx)
 	return -1;
 }
 
+/* Encode header field name <n> value <v> into <buf> buffer using QPACK. Strip
+ * any leading/trailing WS in value prior to encoding.
+ *
+ * Returns 0 on success else non zero.
+ */
+static int h3_encode_header(struct buffer *buf,
+                            const struct ist n, const struct ist v)
+{
+	struct ist v_strip;
+	char *ptr;
+
+	/* trim leading/trailing LWS */
+	for (v_strip = v; istlen(v_strip); --v_strip.len) {
+		ptr = istptr(v_strip);
+		if (unlikely(HTTP_IS_LWS(*ptr)))
+			++v_strip.ptr;
+		else if (!unlikely(HTTP_IS_LWS(ptr[istlen(v_strip) - 1])))
+			break;
+	}
+
+	return qpack_encode_header(buf, n, v_strip);
+}
+
 static int h3_resp_headers_send(struct qcs *qcs, struct htx *htx)
 {
 	int err;
@@ -1679,7 +1702,7 @@ static int h3_resp_headers_send(struct qcs *qcs, struct htx *htx)
 			list[hdr].v = ist("trailers");
 		}
 
-		if (qpack_encode_header(&headers_buf, list[hdr].n, list[hdr].v))
+		if (h3_encode_header(&headers_buf, list[hdr].n, list[hdr].v))
 			goto err_full;
 	}
 
@@ -1839,7 +1862,7 @@ static int h3_resp_trailers_send(struct qcs *qcs, struct htx *htx)
 			continue;
 		}
 
-		if (qpack_encode_header(&headers_buf, list[hdr].n, list[hdr].v)) {
+		if (h3_encode_header(&headers_buf, list[hdr].n, list[hdr].v)) {
 			TRACE_STATE("not enough room for all trailers", H3_EV_TX_FRAME|H3_EV_TX_HDR, qcs->qcc->conn, qcs);
 			if (qcc_release_stream_txbuf(qcs))
 				goto end;