gnutls_init: added flag for automatic re-authentication

This introduces the GNUTLS_AUTO_REAUTH gnutls_init() flag and makes
re-authentication under TLS simpler to enable and use.

Resolves #571

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

13 files changed, 992 insertions, 40 deletions

diff --git a/NEWS b/NEWS
index c5246bf334..3b5e914886 100644
--- a/NEWS
+++ b/NEWS
@@ -5,6 +5,15 @@ Copyright (C) 2000-2016 Free Software Foundation, Inc.
 Copyright (C) 2013-2017 Nikos Mavrogiannopoulos
 See the end for copying conditions.
 
+* Version 3.6.5 (unreleased)
+
+** libgnutls: Provide the option of transparent re-handshake/reauthentication
+   when the GNUTLS_AUTO_REAUTH flag is specified in gnutls_init().
+
+** API and ABI modifications:
+GNUTLS_AUTO_REAUTH: Added
+
+
 * Version 3.6.4 (released 2018-09-24)
 
 ** libgnutls: Added the final (RFC8446) version numbering of the TLS1.3 protocol.
diff --git a/doc/cha-gtls-app.texi b/doc/cha-gtls-app.texi
index 0288543482..1575c8fa52 100644
--- a/doc/cha-gtls-app.texi
+++ b/doc/cha-gtls-app.texi
@@ -1835,6 +1835,12 @@ Due to limitations of early protocol versions, it is required to check whether
 safe renegotiation is in place, i.e., using @funcref{gnutls_safe_renegotiation_status},
 which ensures that the server remains the same as the initial.
 
+To make re-authentication transparent to the application when requested
+by the server, use the @code{GNUTLS_AUTO_REAUTH} flag on the
+@funcref{gnutls_init} call. In that case the re-authentication will happen
+in the call of @funcref{gnutls_record_recv} that received the
+reauthentication request.
+
 @showfuncdesc{gnutls_safe_renegotiation_status}
 
 @subsubsection Server side
@@ -1877,6 +1883,12 @@ A client receiving a re-authentication request will "see" the error code
 @code{GNUTLS_E_REAUTH_REQUEST} at @funcref{gnutls_record_recv}. At this
 point, it should also call @funcref{gnutls_reauth}.
 
+To make re-authentication transparent to the application when requested
+by the server, use the @code{GNUTLS_AUTO_REAUTH} and @code{GNUTLS_POST_HANDSHAKE_AUTH}
+flags on the @funcref{gnutls_init} call. In that case the re-authentication will happen
+in the call of @funcref{gnutls_record_recv} that received the
+reauthentication request.
+
 @node Parameter generation
 @subsection Parameter generation
 @cindex parameter generation
diff --git a/lib/gnutls_int.h b/lib/gnutls_int.h
index 2574f4e420..4a514ccc71 100644
--- a/lib/gnutls_int.h
+++ b/lib/gnutls_int.h
@@ -314,7 +314,9 @@ typedef enum recv_state_t {
 	RECV_STATE_ASYNC_HANDSHAKE, /* an incomplete async handshake message was seen */
 	/* server-side early start under TLS1.3; enabled when no client cert is received */
 	RECV_STATE_EARLY_START_HANDLING, /* we are calling gnutls_handshake() within record_recv() */
-	RECV_STATE_EARLY_START /* gnutls_record_recv() should complete the handshake */
+	RECV_STATE_EARLY_START, /* gnutls_record_recv() should complete the handshake */
+	RECV_STATE_REHANDSHAKE, /* gnutls_record_recv() should complete any incoming re-handshake requests */
+	RECV_STATE_REAUTH /* gnutls_record_recv() should complete any incoming reauthentication requests */
 } recv_state_t;
 
 #include "str.h"
diff --git a/lib/handshake-tls13.c b/lib/handshake-tls13.c
index 06c7c01d29..5fed553310 100644
--- a/lib/handshake-tls13.c
+++ b/lib/handshake-tls13.c
@@ -527,6 +527,7 @@ _gnutls13_recv_async_handshake(gnutls_session_t session)
 {
 	int ret;
 	handshake_buffer_st hsk;
+	recv_state_t next_state = RECV_STATE_0;
 
 	/* The following messages are expected asynchronously after
 	 * the handshake process is complete */
@@ -576,9 +577,20 @@ _gnutls13_recv_async_handshake(gnutls_session_t session)
 					goto cleanup;
 				}
 
-				/* Application is expected to handle re-authentication
-				 * explicitly.  */
-				ret = GNUTLS_E_REAUTH_REQUEST;
+				if (session->internals.flags & GNUTLS_AUTO_REAUTH) {
+					ret = gnutls_reauth(session, 0);
+					if (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED) {
+						next_state = RECV_STATE_REAUTH;
+					} else if (ret < 0) {
+						gnutls_assert();
+						goto cleanup;
+					}
+				} else {
+					/* Application is expected to handle re-authentication
+					 * explicitly.  */
+					ret = GNUTLS_E_REAUTH_REQUEST;
+				}
+
 				goto cleanup;
 
 			case GNUTLS_HANDSHAKE_KEY_UPDATE:
@@ -630,7 +642,7 @@ _gnutls13_recv_async_handshake(gnutls_session_t session)
 
 	} while (_gnutls_record_buffer_get_size(session) > 0);
 
-	session->internals.recv_state = RECV_STATE_0;
+	session->internals.recv_state = next_state;
 
 	return 0;
 
@@ -640,7 +652,7 @@ _gnutls13_recv_async_handshake(gnutls_session_t session)
 	if (_gnutls_record_buffer_get_size(session) > 0)
 		session->internals.recv_state = RECV_STATE_ASYNC_HANDSHAKE;
 	else
-		session->internals.recv_state = RECV_STATE_0;
+		session->internals.recv_state = next_state;
 
 	_gnutls_handshake_buffer_clear(&hsk);
 	return ret;
diff --git a/lib/handshake.c b/lib/handshake.c
index b513872ec3..7db134a638 100644
--- a/lib/handshake.c
+++ b/lib/handshake.c
@@ -3468,30 +3468,6 @@ int _gnutls_generate_session_id(uint8_t * session_id, uint8_t *len)
 	return 0;
 }
 
-int
-_gnutls_recv_hello_request(gnutls_session_t session, void *data,
-			   uint32_t data_size)
-{
-	uint8_t type;
-
-	if (session->security_parameters.entity == GNUTLS_SERVER) {
-		gnutls_assert();
-		return GNUTLS_E_UNEXPECTED_PACKET;
-	}
-	if (data_size < 1) {
-		gnutls_assert();
-		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
-	}
-	type = ((uint8_t *) data)[0];
-	if (type == GNUTLS_HANDSHAKE_HELLO_REQUEST) {
-		if (IS_DTLS(session))
-			session->internals.dtls.hsk_read_seq++;
-		return GNUTLS_E_REHANDSHAKE;
-	} else {
-		gnutls_assert();
-		return GNUTLS_E_UNEXPECTED_PACKET;
-	}
-}
 
 /**
  * gnutls_handshake_set_max_packet_length:
diff --git a/lib/handshake.h b/lib/handshake.h
index 184a349a91..38ef848784 100644
--- a/lib/handshake.h
+++ b/lib/handshake.h
@@ -71,8 +71,6 @@
 
 int _gnutls_send_handshake(gnutls_session_t session, mbuffer_st * bufel,
 			   gnutls_handshake_description_t type);
-int _gnutls_recv_hello_request(gnutls_session_t session, void *data,
-			       uint32_t data_size);
 int _gnutls_recv_handshake(gnutls_session_t session,
 			   gnutls_handshake_description_t type,
 			   unsigned int optional, gnutls_buffer_st * buf);
diff --git a/lib/includes/gnutls/gnutls.h.in b/lib/includes/gnutls/gnutls.h.in
index ec8d6f4efc..01cf9a880e 100644
--- a/lib/includes/gnutls/gnutls.h.in
+++ b/lib/includes/gnutls/gnutls.h.in
@@ -411,6 +411,12 @@ typedef enum {
  *   are already taking steps to hide the data processing time. This comes at a performance
  *   penalty.
  * @GNUTLS_ENABLE_CERT_TYPE_NEG: Enable certificate type negotiation extensions (RFC7250).
+ * @GNUTLS_AUTO_REAUTH: Enable transparent re-authentication in client side when the server
+ *    requests to. That is, reauthentication is handled within gnutls_record_recv(), and
+ *    the %GNUTLS_E_REHANDSHAKE or %GNUTLS_E_REAUTH_REQUEST are not returned. This must be
+ *    enabled with %GNUTLS_POST_HANDSHAKE_AUTH for TLS1.3, and it requires to restore interrupted
+ *    calls to gnutls_record_recv() based on the output of gnutls_record_get_direction(), i.e.,
+ *    gnutls_record_recv() could also be interrupted when sending when this flag is enabled.
  *
  * Enumeration of different flags for gnutls_init() function. All the flags
  * can be combined except @GNUTLS_SERVER and @GNUTLS_CLIENT which are mutually
@@ -439,7 +445,8 @@ typedef enum {
 	GNUTLS_NO_AUTO_REKEY = (1<<15),
 	GNUTLS_SAFE_PADDING_CHECK = (1<<16),
 	GNUTLS_ENABLE_EARLY_START = (1<<17),
-	GNUTLS_ENABLE_CERT_TYPE_NEG = (1<<18)
+	GNUTLS_ENABLE_CERT_TYPE_NEG = (1<<18),
+	GNUTLS_AUTO_REAUTH = (1<<19)
 } gnutls_init_flags_t;
 
 /* compatibility defines (previous versions of gnutls
diff --git a/lib/record.c b/lib/record.c
index 745969a732..87b9dee304 100644
--- a/lib/record.c
+++ b/lib/record.c
@@ -756,6 +756,37 @@ record_check_version(gnutls_session_t session,
 	return 0;
 }
 
+static int
+recv_hello_request(gnutls_session_t session, void *data,
+		   uint32_t data_size)
+{
+	uint8_t type;
+
+	if (session->security_parameters.entity == GNUTLS_SERVER)
+		return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET);
+
+	if (data_size < 1)
+		return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
+
+	if (session->internals.handshake_in_progress)
+		return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET);
+
+	type = ((uint8_t *) data)[0];
+	if (type == GNUTLS_HANDSHAKE_HELLO_REQUEST) {
+		if (IS_DTLS(session))
+			session->internals.dtls.hsk_read_seq++;
+		if (session->internals.flags & GNUTLS_AUTO_REAUTH) {
+			session->internals.recv_state = RECV_STATE_REHANDSHAKE;
+			return GNUTLS_E_AGAIN;
+		} else {
+			return GNUTLS_E_REHANDSHAKE;
+		}
+	} else {
+		gnutls_assert();
+		return GNUTLS_E_UNEXPECTED_PACKET;
+	}
+}
+
 /* This function will check if the received record type is
  * the one we actually expect and adds it to the proper
  * buffer. The bufel will be deinitialized after calling
@@ -995,12 +1026,10 @@ record_add_to_buffers(gnutls_session_t session,
 			/* So we accept it, if it is a Hello. If not, this will
 			 * fail and trigger flight retransmissions after some time. */
 			ret =
-			    _gnutls_recv_hello_request(session,
-						       bufel->msg.data,
-						       bufel->msg.size);
+			    recv_hello_request(session,
+					       bufel->msg.data,
+					       bufel->msg.size);
 			goto unexpected_packet;
-
-			break;
 		default:
 
 			_gnutls_record_log
@@ -1555,6 +1584,30 @@ check_session_status(gnutls_session_t session, unsigned ms)
 	}
 
 	switch (session->internals.recv_state) {
+	case RECV_STATE_REAUTH:
+		session->internals.recv_state = RECV_STATE_0;
+
+		ret = gnutls_reauth(session, 0);
+		if (ret < 0) {
+			/* a temp or fatal error, make sure we reset the state
+			 * so we can resume on temp errors */
+			session->internals.recv_state = RECV_STATE_REAUTH;
+			return gnutls_assert_val(ret);
+		}
+
+		return 1;
+	case RECV_STATE_REHANDSHAKE:
+		session->internals.recv_state = RECV_STATE_0;
+
+		ret = gnutls_handshake(session);
+		if (ret < 0) {
+			/* a temp or fatal error, make sure we reset the state
+			 * so we can resume on temp errors */
+			session->internals.recv_state = RECV_STATE_REHANDSHAKE;
+			return gnutls_assert_val(ret);
+		}
+
+		return 1;
 	case RECV_STATE_ASYNC_HANDSHAKE:
 		ret = _gnutls_recv_in_buffers(session, GNUTLS_HANDSHAKE, -1, ms);
 		if (ret < 0 && ret != GNUTLS_E_SESSION_EOF)
diff --git a/lib/tls13/post_handshake.c b/lib/tls13/post_handshake.c
index ca0ed53b0a..c786d8cae3 100644
--- a/lib/tls13/post_handshake.c
+++ b/lib/tls13/post_handshake.c
@@ -145,8 +145,10 @@ int _gnutls13_reauth_server(gnutls_session_t session)
 	    (!(session->internals.flags & GNUTLS_POST_HANDSHAKE_AUTH)))
 		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
 
-	if (session->internals.send_cert_req == 0)
+	if (session->internals.send_cert_req == 0) {
+		_gnutls_debug_log("You need to call gnutls_certificate_server_set_request to enable post handshake auth\n");
 		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
+	}
 
 	switch (REAUTH_STATE) {
 	case REAUTH_STATE0:
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 71d00bcd32..25c2bf624d 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -109,7 +109,7 @@ ctests = tls13/supported_versions tls13/tls12-no-tls13-exts \
 	tls13/cookie tls13/key_share tls13/prf tls13/post-handshake-with-cert-ticket \
 	tls12-rollback-detection tls11-rollback-detection \
 	tls12-check-rollback-val tls11-check-rollback-val tls13/hello_random_value \
-	tls13/post-handshake-with-psk
+	tls13/post-handshake-with-psk tls13/post-handshake-with-cert-auto
 
 ctests += tls13/hello_retry_request
 
@@ -157,6 +157,7 @@ ctests += mini-record-2 simple gnutls_hmac_fast set_pkcs12_cred cert certuniquei
 	 long-session-id mini-x509-callbacks-intr mini-dtls-lowmtu set_x509_key_file-late \
 	 crlverify mini-dtls-discard init_fds mini-record-failure \
 	 tls12-rehandshake-cert-2 custom-urls set_x509_key_mem set_x509_key_file \
+	 tls12-rehandshake-cert-auto eagain-auto-auth \
 	 mini-chain-unsorted x509-verify-with-crl mini-dtls-mtu privkey-verify-broken \
 	 mini-dtls-record-asym key-import-export priority-set priority-set2 \
 	 pubkey-import-export sign-is-secure spki spki-abstract rsa-rsa-pss \
@@ -226,6 +227,7 @@ str_idna_LDADD = $(CMOCKA_LDADD)
 tls10_prf_LDADD = $(CMOCKA_LDADD)
 tls12_prf_LDADD = $(CMOCKA_LDADD)
 eagain_LDADD = $(CMOCKA_LDADD)
+eagain_auto_auth_LDADD = $(CMOCKA_LDADD)
 tls12_rehandshake_cert_LDADD = $(CMOCKA_LDADD)
 
 gnutls_record_overhead_CPPFLAGS = $(AM_CPPFLAGS) \
diff --git a/tests/eagain-auto-auth.c b/tests/eagain-auto-auth.c
new file mode 100644
index 0000000000..441e7c02e4
--- /dev/null
+++ b/tests/eagain-auto-auth.c
@@ -0,0 +1,235 @@
+/*
+ * Copyright (C) 2008-2012 Free Software Foundation, Inc.
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * Author: Simon Josefsson, Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * GnuTLS is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuTLS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+#include <gnutls/abstract.h>
+
+#define RANDOMIZE
+#include "cert-common.h"
+#include "cmocka-common.h"
+
+/* This tests operation under non-blocking mode in TLS1.2/TLS1.3
+ * rekey/rehandshake.
+ */
+static void tls_log_func(int level, const char *str)
+{
+	fprintf(stderr, "<%d>| %s", level, str);
+}
+
+#define MAX_BUF 1024
+#define MSG "Hello TLS, and hi and how are you and more data here... and more... and even more and even more more data..."
+
+static unsigned int cert_asked = 0;
+
+static int cert_callback(gnutls_session_t session,
+			 const gnutls_datum_t * req_ca_rdn, int nreqs,
+			 const gnutls_pk_algorithm_t * sign_algos,
+			 int sign_algos_length, gnutls_pcert_st ** pcert,
+			 unsigned int *pcert_length, gnutls_privkey_t * pkey)
+{
+	cert_asked = 1;
+	*pcert_length = 0;
+	*pcert = NULL;
+	*pkey = NULL;
+
+	return 0;
+}
+
+static void async_handshake(void **glob_state, const char *prio, unsigned rehsk)
+{
+	/* Server stuff. */
+	gnutls_certificate_credentials_t serverx509cred;
+	gnutls_session_t server;
+	int sret, cret;
+	/* Client stuff. */
+	gnutls_certificate_credentials_t clientx509cred;
+	gnutls_session_t client;
+	/* Need to enable anonymous KX specifically. */
+	char buffer[MAX_BUF + 1];
+	int ret, transferred = 0, msglen;
+
+	/* General init. */
+	reset_buffers();
+	cert_asked = 0;
+	gnutls_global_init();
+	gnutls_global_set_log_function(tls_log_func);
+
+	/* Init server */
+	assert_return_code(gnutls_certificate_allocate_credentials(&serverx509cred), 0);
+	assert_return_code(gnutls_certificate_set_x509_key_mem(serverx509cred,
+					    &server_cert, &server_key,
+					    GNUTLS_X509_FMT_PEM), 0);
+	ret = gnutls_init(&server, GNUTLS_SERVER|GNUTLS_POST_HANDSHAKE_AUTH);
+	assert_return_code(ret, 0);
+
+	ret =
+	    gnutls_priority_set_direct(server,
+					prio,
+					NULL);
+	assert_return_code(ret, 0);
+
+
+	ret = gnutls_credentials_set(server, GNUTLS_CRD_CERTIFICATE, serverx509cred);
+	assert_return_code(ret, 0);
+
+	gnutls_transport_set_push_function(server, server_push);
+	gnutls_transport_set_pull_function(server, server_pull);
+	gnutls_transport_set_ptr(server, server);
+
+	/* Init client */
+
+	ret = gnutls_certificate_allocate_credentials(&clientx509cred);
+	assert_return_code(ret, 0);
+
+	gnutls_certificate_set_retrieve_function2(clientx509cred, cert_callback);
+
+	ret = gnutls_init(&client, GNUTLS_CLIENT|GNUTLS_AUTO_REAUTH|GNUTLS_POST_HANDSHAKE_AUTH);
+	ret =
+	    gnutls_priority_set_direct(client,
+					prio,
+					NULL);
+	assert_return_code(ret, 0);
+
+	ret = gnutls_credentials_set(client, GNUTLS_CRD_CERTIFICATE, clientx509cred);
+	assert_return_code(ret, 0);
+
+	gnutls_transport_set_push_function(client, client_push);
+	gnutls_transport_set_pull_function(client, client_pull);
+	gnutls_transport_set_ptr(client, client);
+
+	HANDSHAKE(client, server);
+
+	if (rehsk == 1) {
+		char b[1];
+		unsigned hstarted = 0;
+
+		do {
+			sret = gnutls_rehandshake(server);
+		} while (sret == GNUTLS_E_AGAIN || sret == GNUTLS_E_INTERRUPTED);
+		assert_true(sret == 0);
+		assert_true(gnutls_record_get_direction(server)==1);
+
+		sret = cret = GNUTLS_E_AGAIN;
+		do {
+			if (!hstarted) {
+				sret = gnutls_record_recv(server, b, 1);
+				if (sret == GNUTLS_E_INTERRUPTED) sret = GNUTLS_E_AGAIN;
+
+				if (sret == GNUTLS_E_REHANDSHAKE) {
+					hstarted = 1;
+					sret = GNUTLS_E_AGAIN;
+				}
+				assert_true(sret == GNUTLS_E_AGAIN);
+			}
+
+			if (sret == GNUTLS_E_AGAIN && hstarted) {
+				sret = gnutls_handshake (server);
+				if (sret == GNUTLS_E_INTERRUPTED) sret = GNUTLS_E_AGAIN;
+				assert_true(sret == GNUTLS_E_AGAIN || sret == 0);
+			}
+
+			/* we are done in client side */
+			if (hstarted && gnutls_record_get_direction(client) == 0 && to_client_len == 0)
+				cret = 0;
+
+			if (cret == GNUTLS_E_AGAIN) {
+				cret = gnutls_record_recv(client, b, 1);
+				if (cret == GNUTLS_E_INTERRUPTED) cret = GNUTLS_E_AGAIN;
+			}
+			assert_true(cret == GNUTLS_E_AGAIN || cret >= 0);
+
+		} while (cret == GNUTLS_E_AGAIN || sret == GNUTLS_E_AGAIN);
+		assert_true(hstarted != 0);
+	} else {
+		char b[1];
+
+		gnutls_certificate_server_set_request(server, GNUTLS_CERT_REQUEST);
+
+		do {
+			sret = gnutls_reauth(server, 0);
+		} while (sret == GNUTLS_E_INTERRUPTED);
+
+		assert_true(sret == GNUTLS_E_AGAIN || sret >= 0);
+
+		cret = GNUTLS_E_AGAIN;
+		do {
+			if (cret == GNUTLS_E_AGAIN) {
+				cret = gnutls_record_recv(client, b, 1);
+				if (cret == GNUTLS_E_INTERRUPTED) cret = GNUTLS_E_AGAIN;
+			}
+
+			if (sret == GNUTLS_E_AGAIN) {
+				sret = gnutls_reauth(server, 0);
+				if (sret == GNUTLS_E_INTERRUPTED) sret = GNUTLS_E_AGAIN;
+			}
+
+			/* we are done in client side */
+			if (gnutls_record_get_direction(client) == 0 && to_client_len == 0)
+				cret = 0;
+		} while (cret == GNUTLS_E_AGAIN || sret == GNUTLS_E_AGAIN);
+	}
+	assert_return_code(cret, 0);
+	assert_return_code(sret, 0);
+	assert_return_code(cert_asked, 1);
+
+	msglen = strlen(MSG);
+	TRANSFER(client, server, MSG, msglen, buffer, MAX_BUF);
+
+	assert_true(gnutls_bye(client, GNUTLS_SHUT_WR)>=0);
+	assert_true(gnutls_bye(server, GNUTLS_SHUT_WR)>=0);
+
+	gnutls_deinit(client);
+	gnutls_deinit(server);
+
+	gnutls_certificate_free_credentials(serverx509cred);
+	gnutls_certificate_free_credentials(clientx509cred);
+
+	gnutls_global_deinit();
+}
+
+static void tls12_async_handshake(void **glob_state)
+{
+	async_handshake(glob_state, "NORMAL:-VERS-ALL:+VERS-TLS1.2", 1);
+}
+
+static void tls13_async_handshake(void **glob_state)
+{
+	async_handshake(glob_state, "NORMAL:-VERS-ALL:+VERS-TLS1.3", 0);
+}
+
+int main(void)
+{
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(tls12_async_handshake),
+		cmocka_unit_test(tls13_async_handshake),
+	};
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}
diff --git a/tests/tls12-rehandshake-cert-auto.c b/tests/tls12-rehandshake-cert-auto.c
new file mode 100644
index 0000000000..88975c9ed4
--- /dev/null
+++ b/tests/tls12-rehandshake-cert-auto.c
@@ -0,0 +1,278 @@
+/*
+ * Copyright (C) 2014 Nikos Mavrogiannopoulos
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * GnuTLS is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuTLS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GnuTLS; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#if defined(_WIN32)
+
+int main()
+{
+	exit(77);
+}
+
+#else
+
+#include <string.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/dtls.h>
+#include <signal.h>
+#include <assert.h>
+
+#include "utils.h"
+#include "cert-common.h"
+
+/* This program tests server initiated rehandshake when
+ * handled transparently by the client.
+ */
+
+static void server_log_func(int level, const char *str)
+{
+	fprintf(stderr, "server|<%d>| %s", level, str);
+}
+
+static void client_log_func(int level, const char *str)
+{
+	fprintf(stderr, "client|<%d>| %s", level, str);
+}
+
+
+#define MAX_BUF 1024
+
+static void client(int fd)
+{
+	int ret;
+	char buffer[MAX_BUF + 1];
+	gnutls_anon_client_credentials_t anoncred;
+	gnutls_certificate_credentials_t x509_cred;
+	gnutls_session_t session;
+	/* Need to enable anonymous KX specifically. */
+
+	global_init();
+	memset(buffer, 2, sizeof(buffer));
+
+	if (debug) {
+		gnutls_global_set_log_function(client_log_func);
+		gnutls_global_set_log_level(4);
+	}
+
+	gnutls_anon_allocate_client_credentials(&anoncred);
+	gnutls_certificate_allocate_credentials(&x509_cred);
+
+	/* Initialize TLS session
+	 */
+	gnutls_init(&session, GNUTLS_CLIENT|GNUTLS_AUTO_REAUTH);
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+
+	/* Use default priorities */
+	gnutls_priority_set_direct(session, "NORMAL:-VERS-TLS-ALL:+VERS-TLS1.1:+VERS-TLS1.2", NULL);
+
+	/* put the anonymous credentials to the current session
+	 */
+	gnutls_credentials_set(session, GNUTLS_CRD_ANON, anoncred);
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred);
+
+	gnutls_transport_set_int(session, fd);
+
+	/* Perform the TLS handshake
+	 */
+	do {
+		ret = gnutls_handshake(session);
+	}
+	while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
+
+	if (ret < 0) {
+		fail("client: Handshake failed\n");
+		gnutls_perror(ret);
+		exit(1);
+	} else {
+		if (debug)
+			success("client: Handshake was completed\n");
+	}
+
+	if (debug)
+		success("client: TLS version is: %s\n",
+			gnutls_protocol_get_name
+			(gnutls_protocol_get_version(session)));
+
+	do {
+		ret =
+		    gnutls_record_recv(session, buffer,
+					MAX_BUF);
+	} while (ret == GNUTLS_E_AGAIN
+		 || ret == GNUTLS_E_INTERRUPTED);
+
+	assert(ret == 0);
+
+	gnutls_bye(session, GNUTLS_SHUT_WR);
+	close(fd);
+
+	gnutls_deinit(session);
+
+	gnutls_anon_free_client_credentials(anoncred);
+	gnutls_certificate_free_credentials(x509_cred);
+
+	gnutls_global_deinit();
+}
+
+/* These are global */
+pid_t child;
+
+static void server(int fd)
+{
+	int ret;
+	char buffer[MAX_BUF + 1];
+	gnutls_session_t session;
+	gnutls_anon_server_credentials_t anoncred;
+	gnutls_certificate_credentials_t x509_cred;
+
+	/* this must be called once in the program
+	 */
+	global_init();
+	memset(buffer, 0, sizeof(buffer));
+
+	if (debug) {
+		gnutls_global_set_log_function(server_log_func);
+		gnutls_global_set_log_level(4);
+	}
+
+	gnutls_certificate_allocate_credentials(&x509_cred);
+	gnutls_certificate_set_x509_key_mem(x509_cred, &server_cert,
+					    &server_key, GNUTLS_X509_FMT_PEM);
+
+	gnutls_anon_allocate_server_credentials(&anoncred);
+
+	gnutls_init(&session, GNUTLS_SERVER);
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+
+	/* avoid calling all the priority functions, since the defaults
+	 * are adequate.
+	 */
+	gnutls_priority_set_direct(session, "NORMAL:-VERS-TLS-ALL:+VERS-TLS1.1:+VERS-TLS1.2", NULL);
+
+	gnutls_credentials_set(session, GNUTLS_CRD_ANON, anoncred);
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred);
+
+	gnutls_transport_set_int(session, fd);
+
+	do {
+		ret = gnutls_handshake(session);
+	}
+	while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
+	if (ret < 0) {
+		close(fd);
+		gnutls_deinit(session);
+		fail("server: Handshake has failed (%s)\n\n",
+		     gnutls_strerror(ret));
+	}
+	if (debug)
+		success("server: Handshake was completed\n");
+
+	if (debug)
+		success("server: TLS version is: %s\n",
+			gnutls_protocol_get_name
+			(gnutls_protocol_get_version(session)));
+
+	if (debug)
+		success("server: sending rehandshake request\n");
+
+	do {
+		ret = gnutls_rehandshake(session);
+	} while(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED);
+	if (ret < 0) {
+		fail("Error sending %d byte packet: %s\n",
+		     (int)sizeof(buffer), gnutls_strerror(ret));
+	}
+
+	if (debug)
+		success("server: starting handshake\n");
+
+	ret = gnutls_handshake(session);
+	if (ret < 0) {
+		fail("server: didn't complete handshake: %s\n", gnutls_strerror(ret));
+	}
+
+	if (debug)
+		success("server: re-handshake is complete\n");
+
+	do {
+		ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
+	} while(ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED);
+
+	close(fd);
+	gnutls_deinit(session);
+
+	gnutls_anon_free_server_credentials(anoncred);
+	gnutls_certificate_free_credentials(x509_cred);
+
+	gnutls_global_deinit();
+
+	if (debug)
+		success("server: finished\n");
+}
+
+void doit(void)
+{
+	signal(SIGCHLD, SIG_IGN);
+	signal(SIGPIPE, SIG_IGN);
+
+	int fd[2];
+	int ret;
+	int status = 0;
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
+	if (ret < 0) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	child = fork();
+	if (child < 0) {
+		perror("fork");
+		fail("fork");
+		exit(1);
+	}
+
+	if (child) {
+		/* parent */
+		close(fd[1]);
+		server(fd[0]);
+		wait(&status);
+		check_wait_status(status);
+	} else {
+		close(fd[0]);
+		client(fd[1]);
+		exit(0);
+	}
+}
+
+#endif				/* _WIN32 */
diff --git a/tests/tls13/post-handshake-with-cert-auto.c b/tests/tls13/post-handshake-with-cert-auto.c
new file mode 100644
index 0000000000..9d920da80c
--- /dev/null
+++ b/tests/tls13/post-handshake-with-cert-auto.c
@@ -0,0 +1,366 @@
+/*
+ * Copyright (C) 2017-2018 Red Hat, Inc.
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * GnuTLS is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuTLS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#if defined(_WIN32)
+
+int main()
+{
+	exit(77);
+}
+
+#else
+
+#include <string.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/dtls.h>
+#include <signal.h>
+#include <assert.h>
+
+#include "cert-common.h"
+#include "tls13/ext-parse.h"
+#include "utils.h"
+
+#define MAX_AUTHS 4
+
+/* This program tests whether the Post Handshake Auth extension is
+ * present in the client hello, and whether it is missing from server
+ * hello. In addition it contains basic functionality test for
+ * post handshake authentication.
+ */
+
+static void server_log_func(int level, const char *str)
+{
+	fprintf(stderr, "server|<%d>| %s", level, str);
+}
+
+static void client_log_func(int level, const char *str)
+{
+	fprintf(stderr, "client|<%d>| %s", level, str);
+}
+
+#define MAX_BUF 1024
+#define MAX_APP_DATA 3
+
+static void client(int fd, unsigned send_cert, unsigned max_auths)
+{
+	int ret;
+	gnutls_certificate_credentials_t x509_cred;
+	gnutls_session_t session;
+	char buf[64];
+	unsigned i;
+
+	global_init();
+
+	if (debug) {
+		gnutls_global_set_log_function(client_log_func);
+		gnutls_global_set_log_level(7);
+	}
+
+	assert(gnutls_certificate_allocate_credentials(&x509_cred)>=0);
+
+	/* Initialize TLS session
+	 */
+	assert(gnutls_init(&session, GNUTLS_CLIENT|GNUTLS_POST_HANDSHAKE_AUTH|GNUTLS_AUTO_REAUTH)>=0);
+
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+
+	ret = gnutls_priority_set_direct(session, "NORMAL:-VERS-ALL:+VERS-TLS1.3:+VERS-TLS1.2:+VERS-TLS1.0", NULL);
+	if (ret < 0)
+		fail("cannot set TLS 1.3 priorities\n");
+
+
+	if (send_cert) {
+		assert(gnutls_certificate_set_x509_key_mem(x509_cred, &cli_ca3_cert,
+						    &cli_ca3_key,
+						    GNUTLS_X509_FMT_PEM)>=0);
+	}
+
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred);
+
+	gnutls_transport_set_int(session, fd);
+
+	/* Perform the TLS handshake
+	 */
+	do {
+		ret = gnutls_handshake(session);
+	}
+	while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
+
+	if (ret != 0)
+		fail("handshake failed: %s\n", gnutls_strerror(ret));
+
+	if (debug)
+		success("client handshake completed\n");
+
+	gnutls_record_set_timeout(session, 20 * 1000);
+
+	for (i=0;i<max_auths;i++) {
+		if (debug)
+			success("waiting for auth nr %d\n", i);
+
+		do {
+			ret = gnutls_record_recv(session, buf, sizeof(buf));
+		} while (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED);
+
+		if (ret < 0)
+			fail("client: gnutls_record_recv did not succeed as expected: %s\n", gnutls_strerror(ret));
+	}
+
+	assert(ret == 0);
+
+	do {
+		ret = gnutls_bye(session, GNUTLS_SHUT_WR);
+	} while (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED);
+
+	close(fd);
+
+	gnutls_deinit(session);
+
+	gnutls_certificate_free_credentials(x509_cred);
+
+	gnutls_global_deinit();
+}
+
+static unsigned client_hello_ok = 0;
+static unsigned server_hello_ok = 0;
+
+#define TLS_EXT_POST_HANDSHAKE 49
+
+static void parse_ext(void *priv, gnutls_datum_t *msg)
+{
+	if (msg->size != 0) {
+		fail("error in extension length: %d\n", (int)msg->size);
+	}
+}
+
+static int hellos_callback(gnutls_session_t session, unsigned int htype,
+	unsigned post, unsigned int incoming, const gnutls_datum_t *msg)
+{
+	if (htype == GNUTLS_HANDSHAKE_SERVER_HELLO && post == GNUTLS_HOOK_POST) {
+		if (find_server_extension(msg, TLS_EXT_POST_HANDSHAKE, NULL, NULL)) {
+			fail("Post handshake extension seen in server hello!\n");
+		}
+		server_hello_ok = 1;
+
+		return GNUTLS_E_INTERRUPTED;
+	}
+
+	if (htype != GNUTLS_HANDSHAKE_CLIENT_HELLO || post != GNUTLS_HOOK_PRE)
+		return 0;
+
+	if (find_client_extension(msg, TLS_EXT_POST_HANDSHAKE, NULL, parse_ext))
+		client_hello_ok = 1;
+	else
+		fail("Post handshake extension NOT seen in client hello!\n");
+
+	return 0;
+}
+
+static void server(int fd, int err, int type, unsigned max_auths)
+{
+	int ret;
+	char buffer[MAX_BUF + 1];
+	gnutls_session_t session;
+	gnutls_certificate_credentials_t x509_cred;
+	unsigned i, retries;
+
+	/* this must be called once in the program
+	 */
+	global_init();
+	memset(buffer, 0, sizeof(buffer));
+
+	if (debug) {
+		gnutls_global_set_log_function(server_log_func);
+		gnutls_global_set_log_level(6);
+	}
+
+	gnutls_certificate_allocate_credentials(&x509_cred);
+	gnutls_certificate_set_x509_key_mem(x509_cred, &server_cert,
+					    &server_key,
+					    GNUTLS_X509_FMT_PEM);
+
+	gnutls_init(&session, GNUTLS_SERVER|GNUTLS_POST_HANDSHAKE_AUTH);
+
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+	gnutls_handshake_set_hook_function(session, GNUTLS_HANDSHAKE_ANY,
+					   GNUTLS_HOOK_BOTH,
+					   hellos_callback);
+
+	/* avoid calling all the priority functions, since the defaults
+	 * are adequate.
+	 */
+	gnutls_priority_set_direct(session, "NORMAL:+VERS-TLS1.3", NULL);
+
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred);
+
+	gnutls_transport_set_int(session, fd);
+
+	do {
+		ret = gnutls_handshake(session);
+	} while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
+
+	if (ret != 0)
+		fail("handshake failed: %s\n", gnutls_strerror(ret));
+
+	if (!(gnutls_session_get_flags(session) & GNUTLS_SFLAGS_POST_HANDSHAKE_AUTH)) {
+		fail("server: session flags did not contain GNUTLS_SFLAGS_POST_HANDSHAKE_AUTH\n");
+	}
+
+
+	if (client_hello_ok == 0) {
+		fail("server: did not verify the client hello\n");
+	}
+
+	if (server_hello_ok == 0) {
+		fail("server: did not verify the server hello contents\n");
+	}
+
+	if (debug)
+		success("server handshake completed\n");
+
+	gnutls_certificate_server_set_request(session, type);
+
+	/* i = 0 */
+	/* ask peer for re-authentication */
+	retries = 0;
+	do {
+		do {
+			ret = gnutls_reauth(session, 0);
+		} while (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED);
+
+		if (ret == GNUTLS_E_GOT_APPLICATION_DATA) {
+			int ret2;
+			do {
+				ret2 = gnutls_record_recv(session, buffer, sizeof(buffer));
+			} while (ret2 == GNUTLS_E_AGAIN || ret2 == GNUTLS_E_INTERRUPTED);
+
+			if (ret2 < 0)
+				fail("error receiving app data: %s\n", gnutls_strerror(ret2));
+
+			/* sender memsets the message with the retry attempt */
+			assert((uint8_t)buffer[0] == retries);
+			assert(retries < MAX_APP_DATA);
+		}
+
+		retries++;
+	} while (ret == GNUTLS_E_GOT_APPLICATION_DATA);
+
+	if (err) {
+		if (ret != err)
+			fail("server: expected error %s, got: %s\n", gnutls_strerror(err),
+			     gnutls_strerror(ret));
+	} else if (ret != 0)
+		fail("server: gnutls_reauth did not succeed as expected: %s\n", gnutls_strerror(ret));
+
+
+	for (i=1;i<max_auths;i++) {
+		/* ask peer for re-authentication */
+		do {
+			ret = gnutls_reauth(session, 0);
+		} while (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED);
+
+		if (err) {
+			if (ret != err)
+				fail("server: expected error %s, got: %s\n", gnutls_strerror(err),
+				     gnutls_strerror(ret));
+		} else if (ret != 0)
+			fail("server: gnutls_reauth did not succeed as expected: %s\n", gnutls_strerror(ret));
+	}
+
+	do {
+		ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
+	} while (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED);
+
+	close(fd);
+	gnutls_deinit(session);
+
+	gnutls_certificate_free_credentials(x509_cred);
+
+	gnutls_global_deinit();
+
+	if (debug)
+		success("server: client/server hello were verified\n");
+}
+
+static
+void start(const char *name, int err, int type, unsigned max_auths, unsigned send_cert)
+{
+	int fd[2];
+	int ret;
+	pid_t child;
+	int status = 0;
+
+	success("testing %s\n", name);
+
+	client_hello_ok = 0;
+	server_hello_ok = 0;
+
+	signal(SIGCHLD, SIG_IGN);
+	signal(SIGPIPE, SIG_IGN);
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
+	if (ret < 0) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	child = fork();
+	if (child < 0) {
+		perror("fork");
+		fail("fork");
+		exit(1);
+	}
+
+	if (child) {
+		/* parent */
+		close(fd[1]);
+		server(fd[0], err, type, max_auths);
+		kill(child, SIGTERM);
+		wait(&status);
+		check_wait_status(status);
+	} else {
+		close(fd[0]);
+		client(fd[1], send_cert, max_auths);
+		exit(0);
+	}
+
+}
+
+void doit(void)
+{
+	start("multi-reauth", 0, GNUTLS_CERT_REQUIRE, MAX_AUTHS, 1);
+	start("reauth-require with no-cert", GNUTLS_E_NO_CERTIFICATE_FOUND, GNUTLS_CERT_REQUIRE, 1, 0);
+	start("reauth-request with no-cert", 0, GNUTLS_CERT_REQUEST, 1, 0);
+}
+#endif				/* _WIN32 */