Provide an easy way to get debug information from TLSv1.3 handshakes.

This makes it easier to debug TLSv1.3 handshake failures.

"Yes please!" tb@, ok beck@

2 files changed, 61 insertions, 3 deletions

diff --git a/src/lib/libssl/Makefile b/src/lib/libssl/Makefile
index 7631dd4cd4..d88e1e9a73 100644
--- a/src/lib/libssl/Makefile
+++ b/src/lib/libssl/Makefile
@@ -1,4 +1,4 @@
-# $OpenBSD: Makefile,v 1.64 2020/03/13 16:40:42 jsing Exp $
+# $OpenBSD: Makefile,v 1.65 2020/05/10 14:22:51 jsing Exp $
 
 .include <bsd.own.mk>
 .ifndef NOMAN
@@ -20,6 +20,9 @@ CFLAGS+= -DLIBRESSL_INTERNAL
 CFLAGS+= -DLIBRESSL_HAS_TLS1_3_CLIENT
 CFLAGS+= -DLIBRESSL_HAS_TLS1_3_SERVER
 .endif
+.ifdef TLS1_3_DEBUG
+CFLAGS+= -DTLS13_DEBUG
+.endif
 CFLAGS+= -I${.CURDIR}
 
 LDADD+= -L${BSDOBJDIR}/lib/libcrypto -lcrypto
diff --git a/src/lib/libssl/tls13_handshake.c b/src/lib/libssl/tls13_handshake.c
index d3333a2e4a..1d8e78b927 100644
--- a/src/lib/libssl/tls13_handshake.c
+++ b/src/lib/libssl/tls13_handshake.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: tls13_handshake.c,v 1.59 2020/05/09 20:38:19 tb Exp $ */
+/*      $OpenBSD: tls13_handshake.c,v 1.60 2020/05/10 14:22:51 jsing Exp $      */
 /*
  * Copyright (c) 2018-2019 Theo Buehler <tb@openbsd.org>
  * Copyright (c) 2019 Joel Sing <jsing@openbsd.org>
@@ -248,6 +248,52 @@ const enum tls13_message_type handshakes[][TLS13_NUM_MESSAGE_TYPES] = {
 
 const size_t handshake_count = sizeof(handshakes) / sizeof(handshakes[0]);
 
+#ifndef TLS13_DEBUG
+#define DEBUGF(...)
+#else
+#define DEBUGF(...) fprintf(stderr, __VA_ARGS__)
+
+static const char *
+tls13_handshake_mode_name(uint8_t mode)
+{
+        switch (mode) {
+        case TLS13_HS_CLIENT:
+                return "Client";
+        case TLS13_HS_SERVER:
+                return "Server";
+        }
+        return "Unknown";
+}
+
+static const char *
+tls13_handshake_message_name(uint8_t msg_type)
+{
+        switch (msg_type) {
+        case TLS13_MT_CLIENT_HELLO:
+                return "ClientHello";
+        case TLS13_MT_SERVER_HELLO:
+                return "ServerHello";
+        case TLS13_MT_NEW_SESSION_TICKET:
+                return "NewSessionTicket";
+        case TLS13_MT_END_OF_EARLY_DATA:
+                return "EndOfEarlyData";
+        case TLS13_MT_ENCRYPTED_EXTENSIONS:
+                return "EncryptedExtensions";
+        case TLS13_MT_CERTIFICATE:
+                return "Certificate";
+        case TLS13_MT_CERTIFICATE_REQUEST:
+                return "CertificateRequest";
+        case TLS13_MT_CERTIFICATE_VERIFY:
+                return "CertificateVerify";
+        case TLS13_MT_FINISHED:
+                return "Finished";
+        case TLS13_MT_KEY_UPDATE:
+                return "KeyUpdate";
+        }
+        return "Unknown";
+}
+#endif
+
 static const enum tls13_message_type
 tls13_handshake_active_state(struct tls13_ctx *ctx)
 {
@@ -306,6 +352,10 @@ tls13_handshake_perform(struct tls13_ctx *ctx)
                         return TLS13_IO_SUCCESS;
                 }
 
+                DEBUGF("%s %s %s\n", tls13_handshake_mode_name(ctx->mode),
+                    (action->sender == ctx->mode) ? "sending" : "receiving",
+                    tls13_handshake_message_name(action->handshake_type));
+
                 if (ctx->alert)
                         return tls13_send_alert(ctx->rl, ctx->alert);
 
@@ -317,8 +367,13 @@ tls13_handshake_perform(struct tls13_ctx *ctx)
                 if (ctx->alert)
                         return tls13_send_alert(ctx->rl, ctx->alert);
 
-                if (ret <= 0)
+                if (ret <= 0) {
+                        DEBUGF("%s %s returned %d\n",
+                            tls13_handshake_mode_name(ctx->mode),
+                            (action->sender == ctx->mode) ? "send" : "recv",
+                            ret);
                         return ret;
+                }
 
                 if (!tls13_handshake_advance_state_machine(ctx))
                         return TLS13_IO_FAILURE;