From e7bc37918c917b4818df14ff3f310c5868520e54 Mon Sep 17 00:00:00 2001
From: Pierre Ossman <ossman@cendio.se>
Date: Tue, 4 Jun 2019 16:51:30 +0200
Subject: [PATCH] Don't use assert() for error handling

It is excessively harsh in its output, and it can be completely
compiled out which will give an incorrect behaviour.
---
 tcp.c | 49 +++++++++++++++++++++++++++++++++----------------
 1 file changed, 33 insertions(+), 16 deletions(-)

diff --git a/tcp.c b/tcp.c
index 3f8b112..1b16886 100644
--- a/tcp.c
+++ b/tcp.c
@@ -40,9 +40,6 @@
 #include "ssl.h"
 #include "asn.h"
 
-
-#define CHECK(x) assert((x)>=0)
-
 #ifdef _WIN32
 #define socklen_t int
 #define TCP_CLOSE(_sck) closesocket(_sck)
@@ -328,6 +325,17 @@ cert_verify_callback(gnutls_session_t session)
 	return utils_cert_handle_exception(session, status, hostname_mismatch, g_last_server_name);
 }
 
+static void
+gnutls_fatal(const char *text, int status)
+{
+	logger(Core, Error, "%s: %s", text, gnutls_strerror(status));
+	/* TODO: Lookup if exit(1) is just plain wrong, its used here to breakout of
+		fallback code path for connection, eg. if TLS fails, a retry with plain
+		RDP is made.
+	*/
+	exit(1);
+}
+
 /* Establish a SSL/TLS 1.0 connection */
 RD_BOOL
 tcp_tls_connect(void)
@@ -340,18 +348,33 @@ tcp_tls_connect(void)
 	if (!g_ssl_initialized)
 	{
 		gnutls_global_init();
-		CHECK(gnutls_init(&g_tls_session, GNUTLS_CLIENT));
+		err = gnutls_init(&g_tls_session, GNUTLS_CLIENT);
+		if (err < 0) {
+			gnutls_fatal("Could not initialize GnuTLS", err);
+		}
 		g_ssl_initialized = True;
 	}
 
 	/* It is recommended to use the default priorities */
-	//CHECK(gnutls_set_default_priority(g_tls_session));
+	//err = gnutls_set_default_priority(g_tls_session);
 	// Use compatible priority to overcome key validation error
 	// THIS IS TEMPORARY
-	CHECK(gnutls_priority_set_direct(g_tls_session, "NORMAL:%COMPAT", NULL));
-	CHECK(gnutls_certificate_allocate_credentials(&xcred));
-	CHECK(gnutls_credentials_set(g_tls_session, GNUTLS_CRD_CERTIFICATE, xcred));
-	CHECK(gnutls_certificate_set_x509_system_trust(xcred));
+	err = gnutls_priority_set_direct(g_tls_session, "NORMAL:%COMPAT", NULL);
+	if (err < 0) {
+		gnutls_fatal("Could not set GnuTLS priority setting", err);
+	}
+	err = gnutls_certificate_allocate_credentials(&xcred);
+	if (err < 0) {
+		gnutls_fatal("Could not allocate TLS certificate structure", err);
+	}
+	err = gnutls_credentials_set(g_tls_session, GNUTLS_CRD_CERTIFICATE, xcred);
+	if (err < 0) {
+		gnutls_fatal("Could not set TLS certificate structure", err);
+	}
+	err = gnutls_certificate_set_x509_system_trust(xcred);
+	if (err < 0) {
+		gnutls_fatal("Could not load system trust database", err);
+	}
 	gnutls_certificate_set_verify_function(xcred, cert_verify_callback);
 	gnutls_transport_set_int(g_tls_session, g_sock);
 	gnutls_handshake_set_timeout(g_tls_session, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
@@ -366,13 +389,7 @@ tcp_tls_connect(void)
 
 		if (err == GNUTLS_E_CERTIFICATE_ERROR)
 		{
-			logger(Core, Error, "%s(): Certificate error during TLS handshake", __func__);
-
-			/* TODO: Lookup if exit(1) is just plain wrong, its used here to breakout of
-				fallback code path for connection, eg. if TLS fails, a retry with plain
-				RDP is made.
-			*/
-			exit(1);
+			gnutls_fatal("Certificate error during TLS handshake", err);
 		}
 
 		/* Handshake failed with unknown error, lets log */