From: Karl Fleischmann <karl.fleischmann@open-xchange.com>
Date: Thu, 12 Oct 2023 13:38:21 +0000 (+0200)
Subject: lib-smtp: Trigger SNI callback on TLS handshake
X-Git-Tag: 2.4.1~1284
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=077aff696ccd0932909f4dbef9aa69d9f54ad424;p=thirdparty%2Fdovecot%2Fcore.git

lib-smtp: Trigger SNI callback on TLS handshake

Allow individual implementations to handle SNI callback in response to a
TLS handshake.
---

diff --git a/src/lib-smtp/smtp-server-connection.c b/src/lib-smtp/smtp-server-connection.c
index 0317009267..ebd96d2b5d 100644
--- a/src/lib-smtp/smtp-server-connection.c
+++ b/src/lib-smtp/smtp-server-connection.c
@@ -342,6 +342,26 @@ smtp_server_connection_handle_command(struct smtp_server_connection *conn,
 	return (!smtp_server_command_unref(&cmd) || finished);
 }
 
+static int
+smtp_server_connection_sni_callback(const char *name, const char **error_r,
+				    void *context)
+{
+	struct smtp_server_connection *conn = context;
+	struct ssl_iostream_context *ssl_ctx;
+
+	if (conn->callbacks->conn_tls_sni_callback != NULL &&
+	    conn->callbacks->conn_tls_sni_callback(name, error_r, conn) < 0)
+		return -1;
+
+	if (ssl_iostream_server_context_cache_get(conn->set.ssl, &ssl_ctx,
+						  error_r) < 0)
+		return -1;
+
+	ssl_iostream_change_context(conn->ssl_iostream, ssl_ctx);
+	ssl_iostream_context_unref(&ssl_ctx);
+	return 0;
+}
+
 int smtp_server_connection_ssl_init(struct smtp_server_connection *conn)
 {
 	struct ssl_iostream_context *ssl_ctx;
@@ -380,6 +400,8 @@ int smtp_server_connection_ssl_init(struct smtp_server_connection *conn)
 			conn->conn.name, error);
 		return -1;
 	}
+	ssl_iostream_set_sni_callback(
+		conn->ssl_iostream, smtp_server_connection_sni_callback, conn);
 	smtp_server_connection_input_resume(conn);
 
 	conn->ssl_secured = TRUE;
diff --git a/src/lib-smtp/smtp-server.h b/src/lib-smtp/smtp-server.h
index ab04078032..a153f648a0 100644
--- a/src/lib-smtp/smtp-server.h
+++ b/src/lib-smtp/smtp-server.h
@@ -298,6 +298,8 @@ struct smtp_server_callbacks {
 	void (*conn_proxy_data_updated)(void *conn_ctx,
 					const struct smtp_proxy_data *data);
 
+	/* TLS SNI Callback. */
+	int (*conn_tls_sni_callback)(const char *name, const char **error_r, void *context);
 	/* Connection */
 	int (*conn_start_tls)(void *conn_ctx,
 			      struct istream **input, struct ostream **output);