tls13: srv: Deprotect and discard early data records
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 20501c9..bf9a8ca 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -3985,6 +3985,31 @@
rec)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "ssl_decrypt_buf", ret);
+#if defined(MBEDTLS_SSL_EARLY_DATA) && defined(MBEDTLS_SSL_SRV_C)
+ /*
+ * Although the server rejected early data, it might receive early
+ * data as long as it has not received the client Finished message.
+ * It is encrypted with early keys and should be ignored as stated
+ * in section 4.2.10 of RFC 8446:
+ *
+ * "Ignore the extension and return a regular 1-RTT response. The
+ * server then skips past early data by attempting to deprotect
+ * received records using the handshake traffic key, discarding
+ * records which fail deprotection (up to the configured
+ * max_early_data_size). Once a record is deprotected successfully,
+ * it is treated as the start of the client's second flight and the
+ * server proceeds as with an ordinary 1-RTT handshake."
+ */
+ if ((old_msg_type == MBEDTLS_SSL_MSG_APPLICATION_DATA) &&
+ (ssl->discard_early_data_record ==
+ MBEDTLS_SSL_EARLY_DATA_TRY_TO_DEPROTECT_AND_DISCARD)) {
+ MBEDTLS_SSL_DEBUG_MSG(
+ 3, ("EarlyData: deprotect and discard app data records."));
+ /* TODO: Add max_early_data_size check here. */
+ ret = MBEDTLS_ERR_SSL_CONTINUE_PROCESSING;
+ }
+#endif /* MBEDTLS_SSL_EARLY_DATA && MBEDTLS_SSL_SRV_C */
+
#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
if (ret == MBEDTLS_ERR_SSL_UNEXPECTED_CID &&
ssl->conf->ignore_unexpected_cid
@@ -3997,6 +4022,20 @@
return ret;
}
+#if defined(MBEDTLS_SSL_EARLY_DATA) && defined(MBEDTLS_SSL_SRV_C)
+ /*
+ * If the server were discarding protected records that it fails to
+ * deprotect because it has rejected early data, as we have just
+ * deprotected successfully a record, the server has to resume normal
+ * operation and fail the connection if the deprotection of a record
+ * fails.
+ */
+ if (ssl->discard_early_data_record ==
+ MBEDTLS_SSL_EARLY_DATA_TRY_TO_DEPROTECT_AND_DISCARD) {
+ ssl->discard_early_data_record = MBEDTLS_SSL_EARLY_DATA_NO_DISCARD;
+ }
+#endif /* MBEDTLS_SSL_EARLY_DATA && MBEDTLS_SSL_SRV_C */
+
if (old_msg_type != rec->type) {
MBEDTLS_SSL_DEBUG_MSG(4, ("record type after decrypt (before %d): %d",
old_msg_type, rec->type));
diff --git a/tests/suites/test_suite_ssl.data b/tests/suites/test_suite_ssl.data
index c06c0a7..404818d 100644
--- a/tests/suites/test_suite_ssl.data
+++ b/tests/suites/test_suite_ssl.data
@@ -3274,5 +3274,8 @@
TLS 1.3 resume session with ticket
tls13_resume_session_with_ticket
-TLS 1.3 early data
-tls13_early_data
+TLS 1.3 early data, reference
+tls13_early_data:"reference"
+
+TLS 1.3 early data, deprotect and discard
+tls13_early_data:"deprotect and discard"
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index 2d1a757..31a973b 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -3662,9 +3662,10 @@
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_SSL_EARLY_DATA:MBEDTLS_SSL_CLI_C:MBEDTLS_SSL_SRV_C:MBEDTLS_DEBUG_C:MBEDTLS_TEST_AT_LEAST_ONE_TLS1_3_CIPHERSUITE:MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED:MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED:MBEDTLS_MD_CAN_SHA256:MBEDTLS_ECP_HAVE_SECP256R1:MBEDTLS_ECP_HAVE_SECP384R1:MBEDTLS_PK_CAN_ECDSA_VERIFY:MBEDTLS_SSL_SESSION_TICKETS */
-void tls13_early_data()
+void tls13_early_data(char *scenario_string)
{
int ret = -1;
+ int scenario = 0;
unsigned char buf[64];
const char *early_data = "This is early data.";
size_t early_data_len = strlen(early_data);
@@ -3672,6 +3673,18 @@
mbedtls_test_handshake_test_options client_options;
mbedtls_test_handshake_test_options server_options;
mbedtls_ssl_session saved_session;
+ mbedtls_test_ssl_log_pattern server_pattern = { NULL, 0 };
+
+ /*
+ * Determine scenario.
+ */
+ if (strcmp(scenario_string, "reference") == 0) {
+ scenario = 0;
+ } else if (strcmp(scenario_string, "deprotect and discard") == 0) {
+ scenario = 1;
+ } else {
+ TEST_FAIL("Unknown scenario.");
+ }
/*
* Test set-up
@@ -3692,15 +3705,17 @@
mbedtls_ssl_conf_early_data(&client_ep.conf, MBEDTLS_SSL_EARLY_DATA_ENABLED);
server_options.pk_alg = MBEDTLS_PK_ECDSA;
+ server_options.srv_log_fun = mbedtls_test_ssl_log_analyzer;
+ server_options.srv_log_obj = &server_pattern;
ret = mbedtls_test_ssl_endpoint_init(&server_ep, MBEDTLS_SSL_IS_SERVER,
&server_options, NULL, NULL, NULL,
NULL);
TEST_EQUAL(ret, 0);
+ mbedtls_ssl_conf_early_data(&server_ep.conf, MBEDTLS_SSL_EARLY_DATA_ENABLED);
mbedtls_ssl_conf_session_tickets_cb(&server_ep.conf,
mbedtls_test_ticket_write,
mbedtls_test_ticket_parse,
NULL);
- mbedtls_ssl_conf_early_data(&server_ep.conf, MBEDTLS_SSL_EARLY_DATA_ENABLED);
ret = mbedtls_test_mock_socket_connect(&(client_ep.socket),
&(server_ep.socket), 1024);
@@ -3740,6 +3755,16 @@
ret = mbedtls_ssl_set_session(&(client_ep.ssl), &saved_session);
TEST_EQUAL(ret, 0);
+ switch (scenario) {
+ case 1: /* deprotect and discard */
+ mbedtls_debug_set_threshold(3);
+ server_pattern.pattern =
+ "EarlyData: deprotect and discard app data records.";
+ mbedtls_ssl_conf_early_data(&server_ep.conf,
+ MBEDTLS_SSL_EARLY_DATA_DISABLED);
+ break;
+ }
+
TEST_EQUAL(mbedtls_test_move_handshake_to_state(
&(client_ep.ssl), &(server_ep.ssl),
MBEDTLS_SSL_SERVER_HELLO), 0);
@@ -3751,18 +3776,29 @@
early_data_len);
TEST_EQUAL(ret, early_data_len);
- TEST_EQUAL(mbedtls_test_move_handshake_to_state(
- &(server_ep.ssl), &(client_ep.ssl),
- MBEDTLS_SSL_CLIENT_FINISHED), MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA);
+ ret = mbedtls_test_move_handshake_to_state(
+ &(server_ep.ssl), &(client_ep.ssl),
+ MBEDTLS_SSL_HANDSHAKE_WRAPUP);
- TEST_EQUAL(server_ep.ssl.handshake->early_data_accepted, 1);
- TEST_EQUAL(mbedtls_ssl_read_early_data(&(server_ep.ssl), buf, sizeof(buf)),
- early_data_len);
- TEST_MEMORY_COMPARE(buf, early_data_len, early_data, early_data_len);
+ switch (scenario) {
+ case 0:
+ TEST_EQUAL(ret, MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA);
+ TEST_EQUAL(server_ep.ssl.handshake->early_data_accepted, 1);
+ TEST_EQUAL(mbedtls_ssl_read_early_data(&(server_ep.ssl),
+ buf, sizeof(buf)), early_data_len);
+ TEST_MEMORY_COMPARE(buf, early_data_len, early_data, early_data_len);
- TEST_EQUAL(mbedtls_test_move_handshake_to_state(
- &(server_ep.ssl), &(client_ep.ssl),
- MBEDTLS_SSL_HANDSHAKE_OVER), 0);
+ TEST_EQUAL(mbedtls_test_move_handshake_to_state(
+ &(server_ep.ssl), &(client_ep.ssl),
+ MBEDTLS_SSL_HANDSHAKE_WRAPUP), 0);
+ break;
+
+ case 1:
+ TEST_EQUAL(ret, 0);
+ TEST_EQUAL(server_ep.ssl.handshake->early_data_accepted, 0);
+ TEST_EQUAL(server_pattern.counter, 1);
+ break;
+ }
exit:
mbedtls_test_ssl_endpoint_free(&client_ep, NULL);
@@ -3770,6 +3806,7 @@
mbedtls_test_free_handshake_options(&client_options);
mbedtls_test_free_handshake_options(&server_options);
mbedtls_ssl_session_free(&saved_session);
+ mbedtls_debug_set_threshold(0);
PSA_DONE();
}
/* END_CASE */