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Support importing/exporting DTLS sessions with encrypt-then-mac options #10544

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28 changes: 24 additions & 4 deletions src/internal.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1423,7 +1423,9 @@ static int ExportOptions(WOLFSSL* ssl, byte* exp, word32 len, byte ver,
exp[idx++] = options->acceptState;
exp[idx++] = options->asyncState;

if (type == WOLFSSL_EXPORT_TLS) {
/* Encrypt-Then-MAC state. Historically only serialized for TLS; export
* version 6 and later also serialize it for DTLS. */
if (type == WOLFSSL_EXPORT_TLS || ver > WOLFSSL_EXPORT_VERSION_5) {
#ifdef HAVE_ENCRYPT_THEN_MAC
exp[idx++] = options->disallowEncThenMac;
exp[idx++] = options->encThenMac;
Expand Down Expand Up @@ -1502,6 +1504,13 @@ static int ImportOptions(WOLFSSL* ssl, const byte* exp, word32 len, byte ver,
}
break;

case WOLFSSL_EXPORT_VERSION_5:
if (len < DTLS_EXPORT_OPT_SZ_5) {
WOLFSSL_MSG("Sanity check on buffer size failed");
return BAD_FUNC_ARG;
}
break;
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JacobBarthelmeh marked this conversation as resolved.

case WOLFSSL_EXPORT_VERSION_4:
if (len < DTLS_EXPORT_OPT_SZ_4) {
WOLFSSL_MSG("Sanity check on buffer size failed");
Expand Down Expand Up @@ -1628,7 +1637,9 @@ static int ImportOptions(WOLFSSL* ssl, const byte* exp, word32 len, byte ver,
options->acceptState = exp[idx++];
options->asyncState = exp[idx++];

if (type == WOLFSSL_EXPORT_TLS) {
/* Encrypt-Then-MAC state. Historically only serialized for TLS; export
* version 6 and later also serialize it for DTLS. */
if (type == WOLFSSL_EXPORT_TLS || ver > WOLFSSL_EXPORT_VERSION_5) {
#ifdef HAVE_ENCRYPT_THEN_MAC
options->disallowEncThenMac = exp[idx++];
options->encThenMac = exp[idx++];
Expand Down Expand Up @@ -1723,8 +1734,8 @@ static int ImportPeerInfo(WOLFSSL* ssl, const byte* buf, word32 len, byte ver)
word16 port;
char ip[MAX_EXPORT_IP];

if (ver != WOLFSSL_EXPORT_VERSION && ver != WOLFSSL_EXPORT_VERSION_4 &&
ver != WOLFSSL_EXPORT_VERSION_3) {
if (ver != WOLFSSL_EXPORT_VERSION && ver != WOLFSSL_EXPORT_VERSION_5 &&
ver != WOLFSSL_EXPORT_VERSION_4 && ver != WOLFSSL_EXPORT_VERSION_3) {
WOLFSSL_MSG("Export version not supported");
return BAD_FUNC_ARG;
}
Expand Down Expand Up @@ -1982,6 +1993,15 @@ int wolfSSL_session_import_internal(WOLFSSL* ssl, const unsigned char* buf,
}
break;

case WOLFSSL_EXPORT_VERSION_5:
if (type == WOLFSSL_EXPORT_DTLS) {
optSz = DTLS_EXPORT_OPT_SZ_5;
}
else {
optSz = TLS_EXPORT_OPT_SZ_5;
}
break;

case WOLFSSL_EXPORT_VERSION_4:
if (type == WOLFSSL_EXPORT_DTLS) {
optSz = DTLS_EXPORT_OPT_SZ_4;
Expand Down
98 changes: 98 additions & 0 deletions tests/api/test_dtls.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3294,3 +3294,101 @@ int test_dtls_set_session_min_downgrade(void)
#endif
return EXPECT_RESULT();
}

#if defined(HAVE_MANUAL_MEMIO_TESTS_DEPENDENCIES) && defined(WOLFSSL_DTLS) && \
defined(WOLFSSL_SESSION_EXPORT) && defined(HAVE_ENCRYPT_THEN_MAC) && \
!defined(WOLFSSL_AEAD_ONLY) && !defined(WOLFSSL_NO_TLS12) && \
!defined(NO_RSA) && !defined(NO_AES) && defined(HAVE_AES_CBC) && \
!defined(NO_SHA256) && defined(HAVE_ECC)
/* Dummy peer callbacks so the DTLS exporter/importer has peer information to
* work with (the library requires these unless built with
* WOLFSSL_SESSION_EXPORT_NOPEER). */
static int test_dtls_export_etm_get_peer(WOLFSSL* ssl, char* ip, int* ipSz,
unsigned short* port, int* fam)
{
(void)ssl;
ip[0] = -1;
*ipSz = 1;
*port = 1;
*fam = 2;
return 1;
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}

static int test_dtls_export_etm_set_peer(WOLFSSL* ssl, char* ip, int ipSz,
unsigned short port, int fam)
{
(void)ssl;
if (ip[0] != -1 || ipSz != 1 || port != 1 || fam != 2)
return 0;
return 1;
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}
#endif

/* Regression test for DTLS session export/import dropping the Encrypt-Then-MAC
* options. Historically the ETM option fields were only serialized for TLS, so
* a re-imported DTLS session lost the negotiated ETM state and broke the record
* layer. Establish a DTLS 1.2 connection with a CBC cipher suite (where ETM
* applies), export the session, re-import it into a fresh WOLFSSL, and confirm
* the ETM option fields survive the round trip. */
int test_dtls12_export_import_etm(void)
{
EXPECT_DECLS;
#if defined(HAVE_MANUAL_MEMIO_TESTS_DEPENDENCIES) && defined(WOLFSSL_DTLS) && \
defined(WOLFSSL_SESSION_EXPORT) && defined(HAVE_ENCRYPT_THEN_MAC) && \
!defined(WOLFSSL_AEAD_ONLY) && !defined(WOLFSSL_NO_TLS12) && \
!defined(NO_RSA) && !defined(NO_AES) && defined(HAVE_AES_CBC) && \
!defined(NO_SHA256) && defined(HAVE_ECC)
/* TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 - a CBC suite, where ETM applies. */
const char* cbcSuite = "ECDHE-RSA-AES128-SHA256";
WOLFSSL_CTX *ctx_c = NULL, *ctx_s = NULL;
WOLFSSL *ssl_c = NULL, *ssl_s = NULL;
WOLFSSL *ssl_imp = NULL;
struct test_memio_ctx test_ctx;
unsigned char* session = NULL;
unsigned int sessionSz = 0;

XMEMSET(&test_ctx, 0, sizeof(test_ctx));
ExpectIntEQ(test_memio_setup(&test_ctx, &ctx_c, &ctx_s, &ssl_c, &ssl_s,
wolfDTLSv1_2_client_method, wolfDTLSv1_2_server_method), 0);
ExpectIntEQ(wolfSSL_set_cipher_list(ssl_c, cbcSuite), WOLFSSL_SUCCESS);
ExpectIntEQ(wolfSSL_set_cipher_list(ssl_s, cbcSuite), WOLFSSL_SUCCESS);

/* The exporter/importer needs peer info callbacks. */
wolfSSL_CTX_SetIOGetPeer(ctx_s, test_dtls_export_etm_get_peer);
wolfSSL_CTX_SetIOSetPeer(ctx_s, test_dtls_export_etm_set_peer);

ExpectIntEQ(test_memio_do_handshake(ssl_c, ssl_s, 10, NULL), 0);

/* Sanity: the handshake itself negotiated ETM on both sides. */
if (ssl_c != NULL)
ExpectIntEQ(ssl_c->options.encThenMac, 1);
if (ssl_s != NULL)
ExpectIntEQ(ssl_s->options.encThenMac, 1);

/* Export the server's DTLS session. */
ExpectIntGE(wolfSSL_dtls_export(ssl_s, NULL, &sessionSz), 0);
ExpectIntGT(sessionSz, 0);
ExpectNotNull(session = (unsigned char*)XMALLOC(sessionSz, NULL,
DYNAMIC_TYPE_TMP_BUFFER));
ExpectIntGE(wolfSSL_dtls_export(ssl_s, session, &sessionSz), 0);

/* Import into a fresh WOLFSSL and confirm the ETM state survived. */
ExpectNotNull(ssl_imp = wolfSSL_new(ctx_s));
ExpectIntGE(wolfSSL_dtls_import(ssl_imp, session, sessionSz), 0);
if (ssl_imp != NULL) {
/* Regression check: pre-fix these were all reset to 0 for DTLS. */
ExpectIntEQ(ssl_imp->options.encThenMac, 1);
ExpectIntEQ(ssl_imp->options.startedETMRead, 1);
ExpectIntEQ(ssl_imp->options.startedETMWrite, 1);
ExpectIntEQ(ssl_imp->options.disallowEncThenMac, 0);
}

XFREE(session, NULL, DYNAMIC_TYPE_TMP_BUFFER);
wolfSSL_free(ssl_imp);
wolfSSL_free(ssl_c);
wolfSSL_free(ssl_s);
wolfSSL_CTX_free(ctx_c);
wolfSSL_CTX_free(ctx_s);
#endif
return EXPECT_RESULT();
}
4 changes: 3 additions & 1 deletion tests/api/test_dtls.h
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Original file line number Diff line number Diff line change
Expand Up @@ -58,6 +58,7 @@ int test_dtls13_no_session_id_echo(void);
int test_dtls13_5_9_0_compat(void);
int test_dtls13_oversized_cert_chain(void);
int test_dtls_set_session_min_downgrade(void);
int test_dtls12_export_import_etm(void);

#define TEST_DTLS_DECLS \
TEST_DECL_GROUP("dtls", test_dtls12_basic_connection_id), \
Expand Down Expand Up @@ -95,5 +96,6 @@ int test_dtls_set_session_min_downgrade(void);
TEST_DECL_GROUP("dtls", test_dtls13_no_session_id_echo), \
TEST_DECL_GROUP("dtls", test_dtls13_oversized_cert_chain), \
TEST_DECL_GROUP("dtls", test_dtls_set_session_min_downgrade), \
TEST_DECL_GROUP("dtls", test_dtls13_5_9_0_compat)
TEST_DECL_GROUP("dtls", test_dtls13_5_9_0_compat), \
TEST_DECL_GROUP("dtls", test_dtls12_export_import_etm)
#endif /* TESTS_API_DTLS_H */
23 changes: 13 additions & 10 deletions wolfssl/internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1632,25 +1632,28 @@ enum Misc {
DTLS_EXPORT_PRO = 165,/* wolfSSL protocol for serialized session */
DTLS_EXPORT_STATE_PRO = 166,/* wolfSSL protocol for serialized state */
TLS_EXPORT_PRO = 167,/* wolfSSL protocol for serialized TLS */
DTLS_EXPORT_OPT_SZ = 62, /* amount of bytes used from Options */
DTLS_EXPORT_OPT_SZ_4 = 61, /* amount of bytes used from Options */
TLS_EXPORT_OPT_SZ = 66, /* amount of bytes used from Options */
TLS_EXPORT_OPT_SZ_4 = 65, /* amount of bytes used from Options */
DTLS_EXPORT_OPT_SZ_3 = 60, /* amount of bytes used from Options */
DTLS_EXPORT_OPT_SZ = 66, /* number of bytes used from Options */
DTLS_EXPORT_OPT_SZ_5 = 62, /* number of bytes used from Options */
DTLS_EXPORT_OPT_SZ_4 = 61, /* number of bytes used from Options */
TLS_EXPORT_OPT_SZ = 66, /* number of bytes used from Options */
TLS_EXPORT_OPT_SZ_5 = 66, /* number of bytes used from Options */
TLS_EXPORT_OPT_SZ_4 = 65, /* number of bytes used from Options */
DTLS_EXPORT_OPT_SZ_3 = 60, /* number of bytes used from Options */
DTLS_EXPORT_KEY_SZ = 325 + (DTLS_SEQ_SZ * 2),
/* max amount of bytes used from Keys */
/* max number of bytes used from Keys */
DTLS_EXPORT_MIN_KEY_SZ = 85 + (DTLS_SEQ_SZ * 2),
/* min amount of bytes used from Keys */
/* min number of bytes used from Keys */
WOLFSSL_EXPORT_TLS = 1,
WOLFSSL_EXPORT_DTLS = 0,
#ifndef WOLFSSL_EXPORT_SPC_SZ
WOLFSSL_EXPORT_SPC_SZ = 16, /* amount of bytes used from CipherSpecs */
WOLFSSL_EXPORT_SPC_SZ = 16, /* number of bytes used from CipherSpecs */
#endif
WOLFSSL_EXPORT_LEN = 2, /* 2 bytes for length and protocol */
WOLFSSL_EXPORT_VERSION = 5, /* wolfSSL version for serialized session */
WOLFSSL_EXPORT_VERSION = 6, /* wolfSSL version for serialized session */

WOLFSSL_EXPORT_VERSION_4 = 4, /* 5.6.4 release and before */
/* older export versions supported */
WOLFSSL_EXPORT_VERSION_5 = 5, /* version before DTLS Encrypt-Then-MAC */
WOLFSSL_EXPORT_VERSION_4 = 4, /* 5.6.4 release and before */
WOLFSSL_EXPORT_VERSION_3 = 3, /* wolfSSL version before TLS 1.3 addition */

MAX_EXPORT_IP = 46, /* max ip size IPv4 mapped IPv6 */
Expand Down
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