tests: added reproducer for client hello random value behavior in DTLS

This adds an equivalent test of tls13/hello_random_value.c for DTLS
and extends the tests for server hello as well.

Relates: #960

Signed-off-by: Nikos Mavrogiannopoulos <nmav@gnutls.org>

2 files changed, 338 insertions, 1 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index c79dcce7e5..ee6c601a45 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -217,7 +217,8 @@ ctests += mini-record-2 simple gnutls_hmac_fast set_pkcs12_cred cert certuniquei
 	 tls-record-size-limit-asym dh-compute ecdh-compute sign-verify-data-newapi \
 	 sign-verify-newapi sign-verify-deterministic iov aead-cipher-vec \
 	 tls13-without-timeout-func buffer status-request-revoked \
-	 set_x509_ocsp_multi_cli kdf-api keylog-func
+	 set_x509_ocsp_multi_cli kdf-api keylog-func \
+	 dtls_hello_random_value
 
 if HAVE_SECCOMP_TESTS
 ctests += dtls-with-seccomp tls-with-seccomp dtls-client-with-seccomp tls-client-with-seccomp
diff --git a/tests/dtls_hello_random_value.c b/tests/dtls_hello_random_value.c
new file mode 100644
index 0000000000..601c8686bf
--- /dev/null
+++ b/tests/dtls_hello_random_value.c
@@ -0,0 +1,336 @@
+/*
+ * Copyright (C) 2017-2020 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 <https://www.gnu.org/licenses/>
+ */
+
+/* This program tests whether the second DTLS client hello contains the same
+ * random value, and whether it is initialized.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#if defined(_WIN32)
+
+/* socketpair isn't supported on Win32. */
+int main(int argc, char **argv)
+{
+	exit(77);
+}
+
+#else
+
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#if !defined(_WIN32)
+#include <sys/wait.h>
+#include <signal.h>
+#endif
+#include <unistd.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/dtls.h>
+#include <assert.h>
+
+#include "utils.h"
+#include "cert-common.h"
+
+const char *side = "";
+
+static void tls_log_func(int level, const char *str)
+{
+	fprintf(stderr, "%s|<%d>| %s", side, level, str);
+}
+
+unsigned char crandom[32];
+static unsigned cb_called = 0;
+
+static int hello_callback(gnutls_session_t session, unsigned int htype,
+			  unsigned post, unsigned int incoming, const gnutls_datum_t *msg)
+{
+	unsigned non_zero = 0, i;
+
+	if (htype == GNUTLS_HANDSHAKE_CLIENT_HELLO && post == GNUTLS_HOOK_POST) {
+		if (cb_called == 0) {
+			/* save first value */
+			gnutls_datum_t tmp;
+			gnutls_session_get_random(session, &tmp, NULL);
+			assert(tmp.size == 32);
+
+			memcpy(crandom, tmp.data, tmp.size);
+			cb_called++;
+
+			/* check if uninitialized */
+			for (i=0;i<32;i++) {
+				if (crandom[i] != 0) {
+					non_zero++;
+				}
+			}
+
+			if (non_zero <= 8) {
+				fail("the client random value seems uninitialized\n");
+			}
+		} else { /* verify it is the same */
+			gnutls_datum_t tmp;
+			gnutls_session_get_random(session, &tmp, NULL);
+
+			assert(tmp.size == 32);
+			if (memcmp(tmp.data, crandom, tmp.size) != 0) {
+				fail("the random values differ!\n");
+			}
+			cb_called++;
+		}
+	} if (htype == GNUTLS_HANDSHAKE_SERVER_HELLO && post == GNUTLS_HOOK_POST) {
+		gnutls_datum_t tmp;
+		gnutls_session_get_random(session, NULL, &tmp);
+		assert(tmp.size == 32);
+
+		for (i=0;i<32;i++) {
+			if (tmp.data[i] != 0) {
+				non_zero++;
+			}
+		}
+		if (non_zero <= 8) {
+			fail("the server random value seems uninitialized\n");
+		}
+	}
+
+	return 0;
+}
+
+static void client(int sd, const char *priority)
+{
+	int ret;
+	gnutls_session_t session;
+	gnutls_certificate_credentials_t clientx509cred;
+
+	gnutls_global_set_log_function(tls_log_func);
+	if (debug)
+		gnutls_global_set_log_level(4711);
+
+	side = "client";
+
+	gnutls_certificate_allocate_credentials(&clientx509cred);
+
+	assert(gnutls_init(&session, GNUTLS_CLIENT|GNUTLS_DATAGRAM)>=0);
+
+	if (!priority) {
+		assert(gnutls_set_default_priority(session) >= 0);
+	} else {
+		assert(gnutls_priority_set_direct(session, priority, NULL) >= 0);
+	}
+
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
+				clientx509cred);
+
+	gnutls_transport_set_int(session, sd);
+	gnutls_dtls_set_mtu(session, 1500);
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+
+	gnutls_handshake_set_hook_function(session, GNUTLS_HANDSHAKE_ANY,
+					   GNUTLS_HOOK_BOTH, hello_callback);
+
+	ret = gnutls_handshake(session);
+
+	if (ret < 0) {
+		fail("client: Handshake failed: %s\n", gnutls_strerror(ret));
+	} else {
+		if (debug)
+			success("client: Handshake was completed\n");
+	}
+
+	if (cb_called != 2) {
+		fail("client: the callback was not seen twice!\n");
+	}
+
+	gnutls_bye(session, GNUTLS_SHUT_WR);
+	close(sd);
+
+	gnutls_deinit(session);
+
+	gnutls_certificate_free_credentials(clientx509cred);
+}
+
+#define MAX_BUF 1024
+#define CLI_ADDR (void*)"test"
+#define CLI_ADDR_LEN 4
+
+static ssize_t
+push(gnutls_transport_ptr_t tr, const void *data, size_t len)
+{
+	int fd = (long int) tr;
+
+	return send(fd, data, len, 0);
+}
+
+static void server(int sd, const char *priority)
+{
+	int ret, csend = 0;
+	char buffer[MAX_BUF + 1];
+	gnutls_certificate_credentials_t serverx509cred;
+	gnutls_dtls_prestate_st prestate;
+	gnutls_session_t session;
+	gnutls_datum_t cookie_key;
+
+	gnutls_global_set_log_function(tls_log_func);
+	if (debug)
+		gnutls_global_set_log_level(4711);
+
+	side = "server";
+
+	ret = gnutls_key_generate(&cookie_key, GNUTLS_COOKIE_KEY_SIZE);
+	if (ret < 0) {
+		fail("Cannot generate key: %s\n", gnutls_strerror(ret));
+	}
+
+	for (;;) {
+		ret = recv(sd, buffer, sizeof(buffer), MSG_PEEK);
+		if (ret < 0) {
+			fail("Cannot receive data\n");
+		}
+
+		memset(&prestate, 0, sizeof(prestate));
+		ret =
+		    gnutls_dtls_cookie_verify(&cookie_key, CLI_ADDR,
+					      CLI_ADDR_LEN, buffer, ret,
+					      &prestate);
+		if (ret < 0) {	/* cookie not valid */
+			if (debug)
+				success("Sending hello verify request\n");
+
+			ret =
+			    gnutls_dtls_cookie_send(&cookie_key, CLI_ADDR,
+						    CLI_ADDR_LEN,
+						    &prestate,
+						    (gnutls_transport_ptr_t)
+						    (long) sd, push);
+			if (ret < 0) {
+				fail("Cannot send data\n");
+			}
+
+			/* discard peeked data */
+			recv(sd, buffer, sizeof(buffer), 0);
+			csend++;
+
+			if (csend > 2) {
+				fail("too many cookies sent\n");
+			}
+
+			continue;
+		}
+
+		/* success */
+		break;
+	}
+
+	assert(gnutls_certificate_allocate_credentials(&serverx509cred)>=0);
+	assert(gnutls_certificate_set_x509_key_mem(serverx509cred,
+					    &server_cert, &server_key,
+					    GNUTLS_X509_FMT_PEM)>=0);
+
+	assert(gnutls_init(&session, GNUTLS_SERVER|GNUTLS_DATAGRAM)>=0);
+	assert(session != NULL);
+
+	if (!priority) {
+		assert(gnutls_set_default_priority(session) >= 0);
+	} else {
+		assert(gnutls_priority_set_direct(session, priority, NULL) >= 0);
+	}
+
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
+				serverx509cred);
+
+	gnutls_transport_set_int(session, sd);
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+	gnutls_dtls_set_mtu(session, 1500);
+
+	gnutls_dtls_prestate_set(session, &prestate);
+
+	ret = gnutls_handshake(session);
+	if (ret < 0) {
+		fail("server: Handshake has failed: %s\n\n",
+		     gnutls_strerror(ret));
+	}
+	if (debug)
+		success("server: Handshake was completed\n");
+
+	/* do not wait for the peer to close the connection.
+	 */
+	gnutls_bye(session, GNUTLS_SHUT_WR);
+	close(sd);
+	gnutls_deinit(session);
+
+	gnutls_certificate_free_credentials(serverx509cred);
+	gnutls_free(cookie_key.data);
+
+	if (debug)
+		success("server: finished\n");
+}
+
+static void start(const char *name, const char *priority)
+{
+	pid_t child;
+	int sockets[2];
+	int err;
+
+	success("testing: %s\n", name);
+	cb_called = 0;
+
+	err = socketpair(AF_UNIX, SOCK_STREAM, 0, sockets);
+	if (err == -1) {
+		perror("socketpair");
+		fail("socketpair failed\n");
+		return;
+	}
+
+	child = fork();
+	if (child < 0) {
+		perror("fork");
+		fail("fork");
+		return;
+	}
+
+	if (child) {
+		int status = 0;
+		/* parent */
+		close(sockets[1]);
+		client(sockets[0], priority);
+		wait(&status);
+		check_wait_status(status);
+	} else {
+		close(sockets[0]);
+		server(sockets[1], priority);
+		exit(0);
+	}
+}
+
+void doit(void)
+{
+	signal(SIGPIPE, SIG_IGN);
+
+	start("default", NULL);
+	start("dtls1.2", "NORMAL:-VERS-ALL:+VERS-DTLS1.2");
+	start("dtls1.0", "NORMAL:-VERS-ALL:+VERS-DTLS1.0");
+}
+
+#endif				/* _WIN32 */