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Merge pull request #10349 from rizlik/dtls13_rtx_fixes

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DTLS13:  Fixes unnecessary client rtx and increase server robustness
This commit is contained in:
Sean Parkinson
2026-05-12 22:19:56 +10:00
committed by GitHub
parent 6942797cd3 74570a2d8a
commit d7bdfd3e90
3 changed files with 243 additions and 15 deletions
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src/dtls13.c
+20 -15
View File
@@ -897,7 +897,7 @@ static void Dtls13RtxRemoveCurAck(WOLFSSL* ssl)
#endif
}
static void Dtls13MaybeSaveClientHello(WOLFSSL* ssl)
static void Dtls13SaveOrFlushClientHello(WOLFSSL* ssl)
{
Dtls13RtxRecord *r, **prev_next;
@@ -906,15 +906,18 @@ static void Dtls13MaybeSaveClientHello(WOLFSSL* ssl)
if (ssl->options.side == WOLFSSL_CLIENT_END &&
ssl->options.connectState >= CLIENT_HELLO_SENT &&
ssl->options.connectState <= HELLO_AGAIN_REPLY &&
ssl->options.downgrade && ssl->options.minDowngrade >= DTLSv1_2_MINOR) {
ssl->options.connectState <= HELLO_AGAIN_REPLY) {
while (r != NULL) {
if (r->handshakeType == client_hello) {
Dtls13RtxRecordUnlink(ssl, prev_next, r);
XFREE(ssl->dtls13ClientHello, ssl->heap, DYNAMIC_TYPE_DTLS_MSG);
ssl->dtls13ClientHello = r->data;
ssl->dtls13ClientHelloSz = r->length;
r->data = NULL;
if (ssl->options.downgrade &&
ssl->options.minDowngrade >= DTLSv1_2_MINOR) {
XFREE(ssl->dtls13ClientHello, ssl->heap,
DYNAMIC_TYPE_DTLS_MSG);
ssl->dtls13ClientHello = r->data;
ssl->dtls13ClientHelloSz = r->length;
r->data = NULL;
}
Dtls13FreeRtxBufferRecord(ssl, r);
return;
}
@@ -934,7 +937,7 @@ static int Dtls13RtxMsgRecvd(WOLFSSL* ssl, enum HandShakeType hs,
ssl->keys.dtls_expected_peer_handshake_number) {
if (hs == server_hello)
Dtls13MaybeSaveClientHello(ssl);
Dtls13SaveOrFlushClientHello(ssl);
/* In the handshake, receiving part of the next flight, acknowledge the
* sent flight. */
@@ -1869,13 +1872,15 @@ static int _Dtls13HandshakeRecv(WOLFSSL* ssl, byte* input, word32 size,
*processedSize = size;
return 0;
}
/* To be able to operate in stateless mode, we assume the ClientHello
* is in order and we use its Handshake Message number and Sequence
* Number for our Tx. */
ssl->keys.dtls_expected_peer_handshake_number =
ssl->keys.dtls_handshake_number =
ssl->keys.dtls_peer_handshake_number;
ssl->dtls13Epochs[0].nextSeqNumber = ssl->keys.curSeq;
if (!ssl->options.dtlsStateful) {
/* To be able to operate in stateless mode, we assume the
* ClientHello is in order and we use its Handshake Message number
* and Sequence Number for our Tx. */
ssl->keys.dtls_expected_peer_handshake_number =
ssl->keys.dtls_handshake_number =
ssl->keys.dtls_peer_handshake_number;
ssl->dtls13Epochs[0].nextSeqNumber = ssl->keys.curSeq;
}
}
if (idx + fragLength > size) {
tests/api/test_dtls.c
+219
View File
@@ -1836,6 +1836,225 @@ int test_dtls_rtx_across_epoch_change(void)
return EXPECT_RESULT();
}
#if defined(HAVE_MANUAL_MEMIO_TESTS_DEPENDENCIES) && \
defined(WOLFSSL_DTLS13) && defined(WOLFSSL_DTLS)
static int test_dtls13_get_message_seq(const char* msg, int msgSz,
word16* msgSeq)
{
int hsOff = DTLS_RECORD_HEADER_SZ;
if (msg == NULL || msgSeq == NULL ||
msgSz < DTLS_RECORD_HEADER_SZ + DTLS_HANDSHAKE_HEADER_SZ) {
return BAD_FUNC_ARG;
}
*msgSeq = ((word16)(byte)msg[hsOff + 4] << 8) |
(word16)(byte)msg[hsOff + 5];
return WOLFSSL_SUCCESS;
}
#endif
int test_dtls13_ch2_rtx_no_ch1(void)
{
EXPECT_DECLS;
#if defined(HAVE_MANUAL_MEMIO_TESTS_DEPENDENCIES) && \
defined(WOLFSSL_DTLS13) && defined(WOLFSSL_DTLS)
WOLFSSL_CTX *ctx_c = NULL, *ctx_s = NULL;
WOLFSSL *ssl_c = NULL, *ssl_s = NULL;
struct test_memio_ctx test_ctx;
const char* msg = NULL;
int msgSz = 0;
word16 ch1Seq = 0;
int i;
int foundCh1Seq = 0;
XMEMSET(&test_ctx, 0, sizeof(test_ctx));
ExpectIntEQ(test_memio_setup(&test_ctx, &ctx_c, &ctx_s, &ssl_c, &ssl_s,
wolfDTLSv1_3_client_method, wolfDTLSv1_3_server_method),
0);
/* To force HRR */
ExpectIntEQ(wolfSSL_NoKeyShares(ssl_c), WOLFSSL_SUCCESS);
/* CH1 */
ExpectIntEQ(wolfSSL_connect(ssl_c), -1);
ExpectIntEQ(wolfSSL_get_error(ssl_c, -1), WOLFSSL_ERROR_WANT_READ);
ExpectIntEQ(test_memio_get_message(&test_ctx, 0, &msg, &msgSz, 0), 0);
ExpectIntGE(msgSz, DTLS_RECORD_HEADER_SZ + DTLS_HANDSHAKE_HEADER_SZ);
ExpectIntEQ(test_dtls13_get_message_seq(msg, msgSz, &ch1Seq),
WOLFSSL_SUCCESS);
/* HRR */
ExpectIntEQ(wolfSSL_accept(ssl_s), -1);
ExpectIntEQ(wolfSSL_get_error(ssl_s, -1), WOLFSSL_ERROR_WANT_READ);
ExpectIntGT(test_ctx.c_msg_count, 0);
/* CH2 */
ExpectIntEQ(wolfSSL_connect(ssl_c), -1);
ExpectIntEQ(wolfSSL_get_error(ssl_c, -1), WOLFSSL_ERROR_WANT_READ);
ExpectIntGT(test_ctx.s_msg_count, 0);
/* Drop CH2 and trigger the client retransmission timeout. */
test_memio_clear_buffer(&test_ctx, 0);
if (wolfSSL_dtls13_use_quick_timeout(ssl_c))
ExpectIntEQ(wolfSSL_dtls_got_timeout(ssl_c), WOLFSSL_SUCCESS);
ExpectIntEQ(wolfSSL_dtls_got_timeout(ssl_c), WOLFSSL_SUCCESS);
ExpectIntGT(test_ctx.s_msg_count, 0);
for (i = 0; i < test_ctx.s_msg_count && EXPECT_SUCCESS(); i++) {
int hsOff = DTLS_RECORD_HEADER_SZ;
word16 msgSeq = 0;
ExpectIntEQ(test_memio_get_message(&test_ctx, 0, &msg, &msgSz, i), 0);
/* memio stores one DTLS record per message in this handshake path. */
if (msgSz >= DTLS_RECORD_HEADER_SZ + DTLS_HANDSHAKE_HEADER_SZ &&
(byte)msg[0] == handshake && msg[hsOff] == client_hello) {
ExpectIntEQ(test_dtls13_get_message_seq(msg, msgSz, &msgSeq),
WOLFSSL_SUCCESS);
if (msgSeq == ch1Seq)
foundCh1Seq = 1;
}
}
ExpectIntEQ(foundCh1Seq, 0);
wolfSSL_free(ssl_c);
wolfSSL_CTX_free(ctx_c);
wolfSSL_free(ssl_s);
wolfSSL_CTX_free(ctx_s);
#endif
return EXPECT_RESULT();
}
int test_dtls13_frag_ch2_with_ch1_rtx(void)
{
EXPECT_DECLS;
#if defined(HAVE_MANUAL_MEMIO_TESTS_DEPENDENCIES) && \
defined(WOLFSSL_DTLS13) && defined(WOLFSSL_DTLS) && \
defined(WOLFSSL_DTLS_MTU) && defined(WOLFSSL_DTLS_CH_FRAG)
WOLFSSL_CTX *ctx_c = NULL, *ctx_s = NULL;
WOLFSSL *ssl_c = NULL, *ssl_s = NULL;
struct test_memio_ctx test_ctx;
char hrr[TEST_MEMIO_BUF_SZ];
int hrrSz = (int)sizeof(hrr);
char ch1Rtx[TEST_MEMIO_BUF_SZ];
int ch1RtxSz = (int)sizeof(ch1Rtx);
char ch2[TEST_MEMIO_BUF_SZ];
int ch2Sz = 0;
int ch2MsgCount = 0;
int ch2MsgSizes[TEST_MEMIO_MAX_MSGS] = {0};
/* The DTLS record sequence number occupies the last 8 bytes of the
* record header. */
int recordSeqOff = DTLS_RECORD_HEADER_SZ - 8;
int ch2Seq = 0;
int ch1RtxSeq = 0;
int off;
int i;
XMEMSET(&test_ctx, 0, sizeof(test_ctx));
ExpectIntEQ(test_memio_setup(&test_ctx, &ctx_c, &ctx_s, &ssl_c, &ssl_s,
wolfDTLSv1_3_client_method, wolfDTLSv1_3_server_method),
0);
/* To force HRR */
ExpectIntEQ(wolfSSL_NoKeyShares(ssl_c), WOLFSSL_SUCCESS);
ExpectIntEQ(wolfSSL_dtls13_allow_ch_frag(ssl_s, 1), WOLFSSL_SUCCESS);
/* CH1 */
ExpectIntEQ(wolfSSL_connect(ssl_c), -1);
ExpectIntEQ(wolfSSL_get_error(ssl_c, -1), WOLFSSL_ERROR_WANT_READ);
/* HRR */
ExpectIntEQ(wolfSSL_accept(ssl_s), -1);
ExpectIntEQ(wolfSSL_get_error(ssl_s, -1), WOLFSSL_ERROR_WANT_READ);
ExpectIntEQ(test_memio_copy_message(&test_ctx, 1, hrr, &hrrSz, 0), 0);
/* Drop HRR, trigger CH1 retransmission, copy and drop it */
test_memio_clear_buffer(&test_ctx, 1);
if (wolfSSL_dtls13_use_quick_timeout(ssl_c))
ExpectIntEQ(wolfSSL_dtls_got_timeout(ssl_c), WOLFSSL_SUCCESS);
ExpectIntEQ(wolfSSL_dtls_got_timeout(ssl_c), WOLFSSL_SUCCESS);
ExpectIntEQ(test_memio_copy_message(&test_ctx, 0, ch1Rtx, &ch1RtxSz, 0), 0);
test_memio_clear_buffer(&test_ctx, 0);
/* Force CH2 fragmentation. MTU must be small enough to fragment but large
* enough that the cookie extension lands in the first fragment, otherwise
* the server can't validate it statelessly and the test scenario (server
* stateful after frag 1) does not hold. With --enable-all (PQ groups in
* supported_groups), the cookie extension can sit ~400 bytes into CH2; 600
* gives margin while still producing multiple fragments (CH2 is ~2KB). */
ExpectIntEQ(wolfSSL_dtls_set_mtu(ssl_c, 600), WOLFSSL_SUCCESS);
/* Forward HRR and let the client create fragmented CH2 */
ExpectIntEQ(test_memio_inject_message(&test_ctx, 1, hrr, hrrSz), 0);
ExpectIntEQ(wolfSSL_connect(ssl_c), -1);
ExpectIntEQ(wolfSSL_get_error(ssl_c, -1), WOLFSSL_ERROR_WANT_READ);
ExpectIntGT(test_ctx.s_msg_count, 1);
ExpectIntLE(test_ctx.s_msg_count, TEST_MEMIO_MAX_MSGS);
ExpectIntLE(test_ctx.s_len, (int)sizeof(ch2));
if (EXPECT_SUCCESS()) {
ch2Sz = test_ctx.s_len;
ch2MsgCount = test_ctx.s_msg_count;
XMEMCPY(ch2, test_ctx.s_buff, ch2Sz);
XMEMCPY(ch2MsgSizes, test_ctx.s_msg_sizes,
sizeof(ch2MsgSizes[0]) * (size_t)ch2MsgCount);
ch2Seq = ((byte)ch2[recordSeqOff + 4] << 8) |
(byte)ch2[recordSeqOff + 5];
ch1RtxSeq = ch2Seq + ch2MsgCount;
/* Synthesize a CH1 retransmission that can pass the replay window after
* the first CH2 fragment makes the server stateful. The handshake
* message_seq remains the original CH1 value; only the DTLS record
* sequence is moved past the fragmented CH2 flight */
ch1Rtx[recordSeqOff + 0] = 0;
ch1Rtx[recordSeqOff + 1] = 0;
ch1Rtx[recordSeqOff + 2] = 0;
ch1Rtx[recordSeqOff + 3] = 0;
ch1Rtx[recordSeqOff + 4] = (byte)(ch1RtxSeq >> 8);
ch1Rtx[recordSeqOff + 5] = (byte)ch1RtxSeq;
}
test_memio_clear_buffer(&test_ctx, 0);
/* Deliver CH2 first fragment only. Now server is stateful */
ExpectIntEQ(test_memio_inject_message(&test_ctx, 0, ch2, ch2MsgSizes[0]), 0);
ExpectIntEQ(wolfSSL_accept(ssl_s), -1);
ExpectIntEQ(wolfSSL_get_error(ssl_s, -1), WOLFSSL_ERROR_WANT_READ);
/* Deliver the retransmitted CH1 between CH2 fragments, it should be
* discarded as rtx */
ExpectIntEQ(test_memio_inject_message(&test_ctx, 0, ch1Rtx, ch1RtxSz), 0);
ExpectIntEQ(wolfSSL_accept(ssl_s), -1);
ExpectIntEQ(wolfSSL_get_error(ssl_s, -1), WOLFSSL_ERROR_WANT_READ);
test_memio_clear_buffer(&test_ctx, 1);
/* Deliver the rest of CH2 */
off = ch2MsgSizes[0];
for (i = 1; i < ch2MsgCount && EXPECT_SUCCESS(); i++) {
ExpectIntEQ(test_memio_inject_message(&test_ctx, 0, ch2 + off,
ch2MsgSizes[i]), 0);
off += ch2MsgSizes[i];
}
/* Restore MTU so the client's input buffer can hold the full server
* flight (e.g. an SH carrying a hybrid PQC key share). */
ExpectIntEQ(wolfSSL_dtls_set_mtu(ssl_c, 1500), WOLFSSL_SUCCESS);
ExpectIntEQ(test_memio_do_handshake(ssl_c, ssl_s, 10, NULL), 0);
wolfSSL_free(ssl_c);
wolfSSL_CTX_free(ctx_c);
wolfSSL_free(ssl_s);
wolfSSL_CTX_free(ctx_s);
#endif
return EXPECT_RESULT();
}
int test_dtls_drop_client_ack(void)
{
EXPECT_DECLS;
tests/api/test_dtls.h
+4
View File
@@ -41,6 +41,8 @@ int test_dtls13_short_read(void);
int test_records_span_network_boundaries(void);
int test_dtls_record_cross_boundaries(void);
int test_dtls_rtx_across_epoch_change(void);
int test_dtls13_ch2_rtx_no_ch1(void);
int test_dtls13_frag_ch2_with_ch1_rtx(void);
int test_dtls_drop_client_ack(void);
int test_dtls_bogus_finished_epoch_zero(void);
int test_dtls_replay(void);
@@ -75,6 +77,8 @@ int test_dtls13_oversized_cert_chain(void);
TEST_DECL_GROUP("dtls", test_records_span_network_boundaries), \
TEST_DECL_GROUP("dtls", test_dtls_record_cross_boundaries), \
TEST_DECL_GROUP("dtls", test_dtls_rtx_across_epoch_change), \
TEST_DECL_GROUP("dtls", test_dtls13_ch2_rtx_no_ch1), \
TEST_DECL_GROUP("dtls", test_dtls13_frag_ch2_with_ch1_rtx), \
TEST_DECL_GROUP("dtls", test_dtls_drop_client_ack), \
TEST_DECL_GROUP("dtls", test_dtls_bogus_finished_epoch_zero), \
TEST_DECL_GROUP("dtls", test_dtls_replay), \