From f783dd959b3e0b1670ab622d6e0cd8930f7c9ad3 Mon Sep 17 00:00:00 2001
From: Frederic Lecaille <flecaille@haproxy.com>
Date: Tue, 23 Jan 2024 11:41:44 +0100
Subject: [PATCH] MINOR: quic: Enable early data at SSL session level (aws-lc)

This patch impacts only the haproxy build against aws-lc TLS stack (USE_OPENSSL_AWSLC).

Implement qc_set_quic_early_data_enabled() new function to enable
early data at session level. To make QUIC O-RTT work, a context string
must be set calling SSL_set_quic_early_data_context(). This is a
subset of the encoded transport parameters which is used for this.
Note that some application level settings should be also added (TODO).

This patch is required to make 0-RTT work for haproxy builds against aws-lc.
---
 src/quic_ssl.c | 40 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/quic_ssl.c b/src/quic_ssl.c
index 314f58797a..af4ca7e543 100644
--- a/src/quic_ssl.c
+++ b/src/quic_ssl.c
@@ -713,6 +713,40 @@ static int qc_ssl_sess_init(struct quic_conn *qc, SSL_CTX *ssl_ctx, SSL **ssl)
 	return ret;
 }
 
+/* Enable early data for <ssl> QUIC TLS session.
+ * Return 1 if succeeded, 0 if not.
+ */
+static int qc_set_quic_early_data_enabled(struct quic_conn *qc, SSL *ssl)
+{
+#if defined(OPENSSL_IS_AWSLC)
+	struct quic_transport_params p = {0};
+	unsigned char buf[128];
+	size_t len;
+
+	/* Apply default values to <p> transport parameters. */
+	quic_transport_params_init(&p, 1);
+	/* The stateless_reset_token transport parameter is not needed. */
+	p.with_stateless_reset_token = 0;
+	len = quic_transport_params_encode(buf, buf + sizeof buf, &p, NULL, 1);
+	if (!len) {
+		TRACE_ERROR("quic_transport_params_encode() failed", QUIC_EV_CONN_RWSEC, qc);
+		return 0;
+	}
+
+	/* XXX TODO: Should also add the application settings. XXX */
+	if (!SSL_set_quic_early_data_context(ssl, buf, len)) {
+		TRACE_ERROR("SSL_set_quic_early_data_context() failed", QUIC_EV_CONN_RWSEC, qc);
+		return 0;
+	}
+
+	SSL_set_early_data_enabled(ssl, 1);
+#else
+	SSL_set_quic_early_data_enabled(ssl, 1);
+#endif
+
+	return 1;
+}
+
 /* Allocate the ssl_sock_ctx from connection <qc>. This creates the tasklet
  * used to process <qc> received packets. The allocated context is stored in
  * <qc.xprt_ctx>.
@@ -748,11 +782,11 @@ int qc_alloc_ssl_sock_ctx(struct quic_conn *qc)
 	if (qc_is_listener(qc)) {
 		if (qc_ssl_sess_init(qc, bc->initial_ctx, &ctx->ssl) == -1)
 		        goto err;
-#if (HA_OPENSSL_VERSION_NUMBER >= 0x10101000L) && !defined(OPENSSL_IS_AWSLC)
+#if (HA_OPENSSL_VERSION_NUMBER >= 0x10101000L)
 #ifndef USE_QUIC_OPENSSL_COMPAT
 		/* Enabling 0-RTT */
-		if (bc->ssl_conf.early_data)
-			SSL_set_quic_early_data_enabled(ctx->ssl, 1);
+		if (bc->ssl_conf.early_data && !qc_set_quic_early_data_enabled(qc, ctx->ssl))
+			goto err;
 #endif
 #endif