From: Artem Boldariev <artem@boldariev.com>
Date: Fri, 14 Jan 2022 12:14:53 +0000 (+0200)
Subject: DoH: ensure that server_send_error_response() is used properly
X-Git-Tag: v9.18.0~16^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ca9fe3559a1e369ee4bf698f5c5f5417258cd8bc;p=thirdparty%2Fbind9.git

DoH: ensure that server_send_error_response() is used properly

The server_send_error_response() function is supposed to be used only
in case of failures and never in case of legitimate requests. Ensure
that ISC_HTTP_ERROR_SUCCESS is never passed there by mistake.
---

diff --git a/lib/isc/netmgr/http.c b/lib/isc/netmgr/http.c
index 5427756a230..0d06c1b9020 100644
--- a/lib/isc/netmgr/http.c
+++ b/lib/isc/netmgr/http.c
@@ -1941,7 +1941,6 @@ static struct http_error_responses {
 	const nghttp2_nv header;
 	const char *desc;
 } error_responses[] = {
-	MAKE_ERROR_REPLY(ISC_HTTP_ERROR_SUCCESS, 200, "OK"),
 	MAKE_ERROR_REPLY(ISC_HTTP_ERROR_BAD_REQUEST, 400, "Bad Request"),
 	MAKE_ERROR_REPLY(ISC_HTTP_ERROR_NOT_FOUND, 404, "Not Found"),
 	MAKE_ERROR_REPLY(ISC_HTTP_ERROR_PAYLOAD_TOO_LARGE, 413,
@@ -1979,7 +1978,11 @@ log_server_error_response(const isc_nmsocket_t *socket,
 static isc_result_t
 server_send_error_response(const isc_http_error_responses_t error,
 			   nghttp2_session *ngsession, isc_nmsocket_t *socket) {
-	void *base = isc_buffer_base(&socket->h2.rbuf);
+	void *base;
+
+	REQUIRE(error != ISC_HTTP_ERROR_SUCCESS);
+
+	base = isc_buffer_base(&socket->h2.rbuf);
 	if (base != NULL) {
 		isc_mem_free(socket->h2.session->mctx, base);
 		isc_buffer_initnull(&socket->h2.rbuf);