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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include "tls/s2n_post_handshake.h"
#include "error/s2n_errno.h"
#include "s2n_test.h"
#include "testlib/s2n_testlib.h"
#include "tls/s2n_connection.h"
#include "tls/s2n_key_update.h"
#include "utils/s2n_safety.h"
/* Include to get access to the handshake state machine
* to verify we don't allow its messages post-handshake.
*/
#include "tls/s2n_handshake_io.c"
#define KEY_UPDATE_MESSAGE_SIZE sizeof(uint8_t) + /* message id */ \
SIZEOF_UINT24 + /* message len */ \
sizeof(uint8_t) /* message */
int s2n_key_update_write(struct s2n_blob *out);
int main(int argc, char **argv)
{
BEGIN_TEST();
/* s2n_post_handshake_recv */
{
/* post_handshake_recv processes a key update requested message */
{
struct s2n_connection *conn;
EXPECT_NOT_NULL(conn = s2n_connection_new(S2N_SERVER));
conn->actual_protocol_version = S2N_TLS13;
conn->secure->cipher_suite = &s2n_tls13_aes_256_gcm_sha384;
EXPECT_FALSE(s2n_atomic_flag_test(&conn->key_update_pending));
/* Write key update requested to conn->in */
EXPECT_SUCCESS(s2n_stuffer_write_uint8(&conn->in, TLS_KEY_UPDATE));
EXPECT_SUCCESS(s2n_stuffer_write_uint24(&conn->in, S2N_KEY_UPDATE_LENGTH));
EXPECT_SUCCESS(s2n_stuffer_write_uint8(&conn->in, S2N_KEY_UPDATE_REQUESTED));
EXPECT_OK(s2n_post_handshake_recv(conn));
EXPECT_TRUE(s2n_atomic_flag_test(&conn->key_update_pending));
EXPECT_SUCCESS(s2n_connection_free(conn));
};
/* post_handshake_recv rejects an unknown post handshake message */
{
struct s2n_connection *conn;
EXPECT_NOT_NULL(conn = s2n_connection_new(S2N_SERVER));
conn->actual_protocol_version = S2N_TLS13;
conn->secure->cipher_suite = &s2n_tls13_aes_256_gcm_sha384;
EXPECT_FALSE(s2n_atomic_flag_test(&conn->key_update_pending));
/* Write key update requested to conn->in */
EXPECT_SUCCESS(s2n_stuffer_write_uint8(&conn->in, -1));
EXPECT_SUCCESS(s2n_stuffer_write_uint24(&conn->in, S2N_KEY_UPDATE_LENGTH));
EXPECT_SUCCESS(s2n_stuffer_write_uint8(&conn->in, S2N_KEY_UPDATE_REQUESTED));
EXPECT_ERROR_WITH_ERRNO(s2n_post_handshake_recv(conn), S2N_ERR_BAD_MESSAGE);
EXPECT_FALSE(s2n_atomic_flag_test(&conn->key_update_pending));
EXPECT_SUCCESS(s2n_connection_free(conn));
};
/* post_handshake_recv processes a malformed post handshake message */
{
struct s2n_connection *conn;
EXPECT_NOT_NULL(conn = s2n_connection_new(S2N_SERVER));
conn->actual_protocol_version = S2N_TLS13;
conn->secure->cipher_suite = &s2n_tls13_aes_256_gcm_sha384;
EXPECT_FALSE(s2n_atomic_flag_test(&conn->key_update_pending));
/* Write key update requested to conn->in */
EXPECT_SUCCESS(s2n_stuffer_write_uint8(&conn->in, TLS_KEY_UPDATE));
EXPECT_SUCCESS(s2n_stuffer_write_uint8(&conn->in, S2N_KEY_UPDATE_LENGTH));
EXPECT_ERROR(s2n_post_handshake_recv(conn));
EXPECT_FALSE(s2n_atomic_flag_test(&conn->key_update_pending));
EXPECT_SUCCESS(s2n_connection_free(conn));
};
/* Functional test: Multiple post handshake messages can be received in the same record */
{
struct s2n_connection *conn = s2n_connection_new(S2N_SERVER);
EXPECT_NOT_NULL(conn);
conn->actual_protocol_version = S2N_TLS13;
conn->secure->cipher_suite = &s2n_tls13_aes_256_gcm_sha384;
uint8_t num_key_updates = 3;
/* Write three key update messages in one record. We cannot call s2n_post_handshake_send
* multiple times here because s2n only sends one handshake message per record */
for (size_t i = 0; i < num_key_updates; i++) {
uint8_t data[KEY_UPDATE_MESSAGE_SIZE] = { 0 };
struct s2n_blob key_update_message = { 0 };
EXPECT_SUCCESS(s2n_blob_init(&key_update_message, data, sizeof(data)));
EXPECT_SUCCESS(s2n_key_update_write(&key_update_message));
EXPECT_SUCCESS(s2n_stuffer_write_bytes(&conn->in, key_update_message.data, key_update_message.size));
}
EXPECT_OK(s2n_post_handshake_recv(conn));
/* All three key update messages have been read */
EXPECT_EQUAL(s2n_stuffer_data_available(&conn->in), 0);
EXPECT_SUCCESS(s2n_connection_free(conn));
};
/* HELLO_REQUEST messages can be received post-handshake. */
{
struct s2n_connection *conn = s2n_connection_new(S2N_CLIENT);
EXPECT_NOT_NULL(conn);
conn->actual_protocol_version = S2N_TLS12;
EXPECT_SUCCESS(s2n_stuffer_write_uint8(&conn->in, TLS_HELLO_REQUEST));
EXPECT_SUCCESS(s2n_stuffer_write_uint24(&conn->in, 0));
EXPECT_OK(s2n_post_handshake_recv(conn));
EXPECT_SUCCESS(s2n_connection_free(conn));
};
/* No non-post handshake messages can be received.
* This means that no handshake message that appears in the handshake state machine
* should be allowed.
*/
{
/* For TLS1.2 */
for (size_t i = 0; i < s2n_array_len(state_machine); i++) {
if (state_machine[i].record_type != TLS_HANDSHAKE) {
break;
}
struct s2n_connection *conn;
EXPECT_NOT_NULL(conn = s2n_connection_new(S2N_SERVER));
conn->actual_protocol_version = S2N_TLS13;
EXPECT_SUCCESS(s2n_stuffer_write_uint8(&conn->in, state_machine[i].message_type));
EXPECT_SUCCESS(s2n_stuffer_write_uint24(&conn->in, 0));
EXPECT_ERROR_WITH_ERRNO(s2n_post_handshake_recv(conn), S2N_ERR_BAD_MESSAGE);
EXPECT_SUCCESS(s2n_connection_free(conn));
}
/* For TLS1.3 */
for (size_t i = 0; i < s2n_array_len(tls13_state_machine); i++) {
if (tls13_state_machine[i].record_type != TLS_HANDSHAKE) {
break;
}
struct s2n_connection *conn;
EXPECT_NOT_NULL(conn = s2n_connection_new(S2N_SERVER));
conn->actual_protocol_version = S2N_TLS13;
EXPECT_SUCCESS(s2n_stuffer_write_uint8(&conn->in, tls13_state_machine[i].message_type));
EXPECT_SUCCESS(s2n_stuffer_write_uint24(&conn->in, 0));
EXPECT_ERROR_WITH_ERRNO(s2n_post_handshake_recv(conn), S2N_ERR_BAD_MESSAGE);
EXPECT_SUCCESS(s2n_connection_free(conn));
}
};
};
/* post_handshake_send */
{
/* Post handshake messages can be sent */
{
DEFER_CLEANUP(struct s2n_connection *conn = s2n_connection_new(S2N_CLIENT),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(conn);
EXPECT_OK(s2n_connection_set_secrets(conn));
DEFER_CLEANUP(struct s2n_stuffer output = { 0 }, s2n_stuffer_free);
EXPECT_SUCCESS(s2n_stuffer_growable_alloc(&output, 0));
EXPECT_SUCCESS(s2n_connection_set_send_io_stuffer(&output, conn));
conn->actual_protocol_version = S2N_TLS13;
s2n_atomic_flag_set(&conn->key_update_pending);
s2n_blocked_status blocked = S2N_NOT_BLOCKED;
EXPECT_SUCCESS(s2n_post_handshake_send(conn, &blocked));
EXPECT_TRUE(s2n_stuffer_data_available(&output) > 0);
};
/* No messages sent if no post-handshake messages required */
{
DEFER_CLEANUP(struct s2n_connection *conn = s2n_connection_new(S2N_CLIENT),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(conn);
EXPECT_OK(s2n_connection_set_secrets(conn));
conn->actual_protocol_version = S2N_TLS13;
s2n_atomic_flag_clear(&conn->key_update_pending);
s2n_blocked_status blocked = S2N_NOT_BLOCKED;
EXPECT_SUCCESS(s2n_post_handshake_send(conn, &blocked));
EXPECT_EQUAL(s2n_stuffer_data_available(&conn->out), 0);
};
/* No messages sent if <TLS1.3 */
{
DEFER_CLEANUP(struct s2n_connection *conn = s2n_connection_new(S2N_CLIENT),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(conn);
EXPECT_OK(s2n_connection_set_secrets(conn));
conn->actual_protocol_version = S2N_TLS12;
s2n_atomic_flag_set(&conn->key_update_pending);
s2n_blocked_status blocked = S2N_NOT_BLOCKED;
EXPECT_SUCCESS(s2n_post_handshake_send(conn, &blocked));
EXPECT_TRUE(s2n_atomic_flag_test(&conn->key_update_pending));
EXPECT_EQUAL(s2n_stuffer_data_available(&conn->out), 0);
};
};
/* Errors while processing post-handshake messages close the connection */
{
struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
EXPECT_NOT_NULL(client_conn);
EXPECT_SUCCESS(s2n_connection_set_cipher_preferences(client_conn, "default_tls13"));
struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER);
EXPECT_NOT_NULL(server_conn);
EXPECT_SUCCESS(s2n_connection_set_blinding(server_conn, S2N_SELF_SERVICE_BLINDING));
EXPECT_SUCCESS(s2n_connection_set_cipher_preferences(server_conn, "default_tls13"));
DEFER_CLEANUP(struct s2n_stuffer io_stuffer = { 0 }, s2n_stuffer_free);
EXPECT_SUCCESS(s2n_stuffer_growable_alloc(&io_stuffer, 0));
EXPECT_SUCCESS(s2n_connection_set_io_stuffers(&io_stuffer, &io_stuffer, client_conn));
EXPECT_SUCCESS(s2n_connection_set_io_stuffers(&io_stuffer, &io_stuffer, server_conn));
/* Send just the ClientHello */
s2n_blocked_status blocked = S2N_NOT_BLOCKED;
EXPECT_OK(s2n_negotiate_until_message(client_conn, &blocked, SERVER_HELLO));
/* Try to read the ClientHello as a post-handshake message */
uint8_t output_buffer[10] = { 0 };
EXPECT_FAILURE_WITH_ERRNO(s2n_recv(server_conn, output_buffer, sizeof(output_buffer), &blocked), S2N_ERR_BAD_MESSAGE);
/* Error closed connection */
EXPECT_TRUE(s2n_connection_check_io_status(server_conn, S2N_IO_CLOSED));
/* Error triggers blinding */
EXPECT_NOT_EQUAL(s2n_connection_get_delay(server_conn), 0);
EXPECT_SUCCESS(s2n_connection_free(client_conn));
EXPECT_SUCCESS(s2n_connection_free(server_conn));
};
END_TEST();
}
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