| /* |
| * TLS 1.3 server-side functions |
| * |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_PROTO_TLS1_3) |
| |
| #include "debug_internal.h" |
| #include "mbedtls/error.h" |
| #include "mbedtls/platform.h" |
| #include "mbedtls/constant_time.h" |
| #include "mbedtls/oid.h" |
| #include "mbedtls/psa_util.h" |
| |
| #include "ssl_misc.h" |
| #include "ssl_tls13_keys.h" |
| #include "ssl_debug_helpers.h" |
| |
| |
| static const mbedtls_ssl_ciphersuite_t *ssl_tls13_validate_peer_ciphersuite( |
| mbedtls_ssl_context *ssl, |
| unsigned int cipher_suite) |
| { |
| const mbedtls_ssl_ciphersuite_t *ciphersuite_info; |
| if (!mbedtls_ssl_tls13_cipher_suite_is_offered(ssl, cipher_suite)) { |
| return NULL; |
| } |
| |
| ciphersuite_info = mbedtls_ssl_ciphersuite_from_id(cipher_suite); |
| if ((mbedtls_ssl_validate_ciphersuite(ssl, ciphersuite_info, |
| ssl->tls_version, |
| ssl->tls_version) != 0)) { |
| return NULL; |
| } |
| return ciphersuite_info; |
| } |
| |
| static void ssl_tls13_select_ciphersuite( |
| mbedtls_ssl_context *ssl, |
| const unsigned char *cipher_suites, |
| const unsigned char *cipher_suites_end, |
| int psk_ciphersuite_id, |
| psa_algorithm_t psk_hash_alg, |
| const mbedtls_ssl_ciphersuite_t **selected_ciphersuite_info) |
| { |
| *selected_ciphersuite_info = NULL; |
| |
| /* |
| * In a compliant ClientHello the byte-length of the list of ciphersuites |
| * is even and this function relies on this fact. This should have been |
| * checked in the main ClientHello parsing function. Double check here. |
| */ |
| if ((cipher_suites_end - cipher_suites) & 1) { |
| return; |
| } |
| |
| for (const unsigned char *p = cipher_suites; |
| p < cipher_suites_end; p += 2) { |
| /* |
| * "cipher_suites_end - p is even" is an invariant of the loop. As |
| * cipher_suites_end - p > 0, we have cipher_suites_end - p >= 2 and it |
| * is thus safe to read two bytes. |
| */ |
| uint16_t id = MBEDTLS_GET_UINT16_BE(p, 0); |
| |
| const mbedtls_ssl_ciphersuite_t *info = |
| ssl_tls13_validate_peer_ciphersuite(ssl, id); |
| if (info == NULL) { |
| continue; |
| } |
| |
| /* |
| * If a valid PSK ciphersuite identifier has been passed in, we want |
| * an exact match. |
| */ |
| if (psk_ciphersuite_id != 0) { |
| if (id != psk_ciphersuite_id) { |
| continue; |
| } |
| } else if (psk_hash_alg != PSA_ALG_NONE) { |
| if (mbedtls_md_psa_alg_from_type((mbedtls_md_type_t) info->mac) != |
| psk_hash_alg) { |
| continue; |
| } |
| } |
| |
| *selected_ciphersuite_info = info; |
| return; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("No matched ciphersuite, psk_ciphersuite_id=%x, psk_hash_alg=%x", |
| (unsigned) psk_ciphersuite_id, psk_hash_alg)); |
| } |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| /* From RFC 8446: |
| * |
| * enum { psk_ke(0), psk_dhe_ke(1), (255) } PskKeyExchangeMode; |
| * struct { |
| * PskKeyExchangeMode ke_modes<1..255>; |
| * } PskKeyExchangeModes; |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_parse_key_exchange_modes_ext(mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end) |
| { |
| const unsigned char *p = buf; |
| size_t ke_modes_len; |
| int ke_modes = 0; |
| |
| /* Read ke_modes length (1 Byte) */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 1); |
| ke_modes_len = *p++; |
| /* Currently, there are only two PSK modes, so even without looking |
| * at the content, something's wrong if the list has more than 2 items. */ |
| if (ke_modes_len > 2) { |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, |
| MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); |
| return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; |
| } |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, ke_modes_len); |
| |
| while (ke_modes_len-- != 0) { |
| switch (*p++) { |
| case MBEDTLS_SSL_TLS1_3_PSK_MODE_PURE: |
| ke_modes |= MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK; |
| MBEDTLS_SSL_DEBUG_MSG(3, ("Found PSK KEX MODE")); |
| break; |
| case MBEDTLS_SSL_TLS1_3_PSK_MODE_ECDHE: |
| ke_modes |= MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL; |
| MBEDTLS_SSL_DEBUG_MSG(3, ("Found PSK_EPHEMERAL KEX MODE")); |
| break; |
| default: |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, |
| MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); |
| return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; |
| } |
| } |
| |
| ssl->handshake->tls13_kex_modes = ke_modes; |
| return 0; |
| } |
| |
| /* |
| * Non-error return values of |
| * ssl_tls13_offered_psks_check_identity_match_ticket() and |
| * ssl_tls13_offered_psks_check_identity_match(). They are positive to |
| * not collide with error codes that are negative. Zero |
| * (SSL_TLS1_3_PSK_IDENTITY_MATCH) in case of success as it may be propagated |
| * up by the callers of this function as a generic success condition. |
| * |
| * The return value SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE means |
| * that the pre-shared-key identity matches that of a ticket or an externally- |
| * provisioned pre-shared-key. We have thus been able to retrieve the |
| * attributes of the pre-shared-key but at least one of them does not meet |
| * some criteria and the pre-shared-key cannot be used. For example, a ticket |
| * is expired or its version is not TLS 1.3. Note eventually that the return |
| * value SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE does not have |
| * anything to do with binder check. A binder check is done only when a |
| * suitable pre-shared-key has been selected and only for that selected |
| * pre-shared-key: if the binder check fails, we fail the handshake and we do |
| * not try to find another pre-shared-key for which the binder check would |
| * succeed as recommended by the specification. |
| */ |
| #define SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH 2 |
| #define SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE 1 |
| #define SSL_TLS1_3_PSK_IDENTITY_MATCH 0 |
| |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_key_exchange_is_psk_available(mbedtls_ssl_context *ssl); |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_key_exchange_is_psk_ephemeral_available(mbedtls_ssl_context *ssl); |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_offered_psks_check_identity_match_ticket( |
| mbedtls_ssl_context *ssl, |
| const unsigned char *identity, |
| size_t identity_len, |
| uint32_t obfuscated_ticket_age, |
| mbedtls_ssl_session *session) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *ticket_buffer; |
| #if defined(MBEDTLS_HAVE_TIME) |
| mbedtls_ms_time_t now; |
| mbedtls_ms_time_t server_age; |
| uint32_t client_age; |
| mbedtls_ms_time_t age_diff; |
| #endif |
| |
| ((void) obfuscated_ticket_age); |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("=> check_identity_match_ticket")); |
| |
| /* Ticket parser is not configured, Skip */ |
| if (ssl->conf->f_ticket_parse == NULL || identity_len == 0) { |
| return SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; |
| } |
| |
| /* We create a copy of the encrypted ticket since the ticket parsing |
| * function is allowed to use its input buffer as an output buffer |
| * (in-place decryption). We do, however, need the original buffer for |
| * computing the PSK binder value. |
| */ |
| ticket_buffer = mbedtls_calloc(1, identity_len); |
| if (ticket_buffer == NULL) { |
| return MBEDTLS_ERR_SSL_ALLOC_FAILED; |
| } |
| memcpy(ticket_buffer, identity, identity_len); |
| |
| ret = ssl->conf->f_ticket_parse(ssl->conf->p_ticket, |
| session, |
| ticket_buffer, identity_len); |
| switch (ret) { |
| case 0: |
| ret = SSL_TLS1_3_PSK_IDENTITY_MATCH; |
| break; |
| |
| case MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED: |
| MBEDTLS_SSL_DEBUG_MSG(3, ("ticket is expired")); |
| ret = SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE; |
| break; |
| |
| case MBEDTLS_ERR_SSL_INVALID_MAC: |
| MBEDTLS_SSL_DEBUG_MSG(3, ("ticket is not authentic")); |
| ret = SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; |
| break; |
| |
| default: |
| MBEDTLS_SSL_DEBUG_RET(1, "ticket_parse", ret); |
| ret = SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; |
| } |
| |
| /* We delete the temporary buffer */ |
| mbedtls_free(ticket_buffer); |
| |
| if (ret != SSL_TLS1_3_PSK_IDENTITY_MATCH) { |
| goto exit; |
| } |
| |
| /* |
| * The identity matches that of a ticket. Now check that it has suitable |
| * attributes and bet it will not be the case. |
| */ |
| ret = SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE; |
| |
| if (session->tls_version != MBEDTLS_SSL_VERSION_TLS1_3) { |
| MBEDTLS_SSL_DEBUG_MSG(3, ("Ticket TLS version is not 1.3.")); |
| goto exit; |
| } |
| |
| #if defined(MBEDTLS_HAVE_TIME) |
| now = mbedtls_ms_time(); |
| |
| if (now < session->ticket_creation_time) { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 3, ("Invalid ticket creation time ( now = %" MBEDTLS_PRINTF_MS_TIME |
| ", creation_time = %" MBEDTLS_PRINTF_MS_TIME " )", |
| now, session->ticket_creation_time)); |
| goto exit; |
| } |
| |
| server_age = now - session->ticket_creation_time; |
| |
| /* RFC 8446 section 4.6.1 |
| * |
| * Servers MUST NOT use any value greater than 604800 seconds (7 days). |
| * |
| * RFC 8446 section 4.2.11.1 |
| * |
| * Clients MUST NOT attempt to use tickets which have ages greater than |
| * the "ticket_lifetime" value which was provided with the ticket. |
| * |
| */ |
| if (server_age > MBEDTLS_SSL_TLS1_3_MAX_ALLOWED_TICKET_LIFETIME * 1000) { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 3, ("Ticket age exceeds limitation ticket_age = %" MBEDTLS_PRINTF_MS_TIME, |
| server_age)); |
| goto exit; |
| } |
| |
| /* RFC 8446 section 4.2.10 |
| * |
| * For PSKs provisioned via NewSessionTicket, a server MUST validate that |
| * the ticket age for the selected PSK identity (computed by subtracting |
| * ticket_age_add from PskIdentity.obfuscated_ticket_age modulo 2^32) is |
| * within a small tolerance of the time since the ticket was issued. |
| * |
| * NOTE: The typical accuracy of an RTC crystal is ±100 to ±20 parts per |
| * million (360 to 72 milliseconds per hour). Default tolerance |
| * window is 6s, thus in the worst case clients and servers must |
| * sync up their system time every 6000/360/2~=8 hours. |
| */ |
| client_age = obfuscated_ticket_age - session->ticket_age_add; |
| age_diff = server_age - (mbedtls_ms_time_t) client_age; |
| if (age_diff < -MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE || |
| age_diff > MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE) { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 3, ("Ticket age outside tolerance window ( diff = %" |
| MBEDTLS_PRINTF_MS_TIME ")", |
| age_diff)); |
| goto exit; |
| } |
| #endif /* MBEDTLS_HAVE_TIME */ |
| |
| /* |
| * All good, we have found a suitable ticket. |
| */ |
| ret = SSL_TLS1_3_PSK_IDENTITY_MATCH; |
| |
| exit: |
| if (ret != SSL_TLS1_3_PSK_IDENTITY_MATCH) { |
| mbedtls_ssl_session_free(session); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("<= check_identity_match_ticket")); |
| return ret; |
| } |
| #endif /* MBEDTLS_SSL_SESSION_TICKETS */ |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_offered_psks_check_identity_match( |
| mbedtls_ssl_context *ssl, |
| const unsigned char *identity, |
| size_t identity_len, |
| uint32_t obfuscated_ticket_age, |
| int *psk_type, |
| mbedtls_ssl_session *session) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| ((void) session); |
| ((void) obfuscated_ticket_age); |
| *psk_type = MBEDTLS_SSL_TLS1_3_PSK_EXTERNAL; |
| |
| MBEDTLS_SSL_DEBUG_BUF(4, "identity", identity, identity_len); |
| |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| ret = ssl_tls13_offered_psks_check_identity_match_ticket( |
| ssl, identity, identity_len, obfuscated_ticket_age, session); |
| if (ret == SSL_TLS1_3_PSK_IDENTITY_MATCH) { |
| *psk_type = MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION; |
| ret = mbedtls_ssl_set_hs_psk(ssl, |
| session->resumption_key, |
| session->resumption_key_len); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_set_hs_psk", ret); |
| return ret; |
| } |
| |
| MBEDTLS_SSL_DEBUG_BUF(4, "Ticket-resumed PSK:", |
| session->resumption_key, |
| session->resumption_key_len); |
| MBEDTLS_SSL_DEBUG_MSG(4, ("ticket: obfuscated_ticket_age: %u", |
| (unsigned) obfuscated_ticket_age)); |
| return SSL_TLS1_3_PSK_IDENTITY_MATCH; |
| } else if (ret == SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE) { |
| return SSL_TLS1_3_PSK_IDENTITY_MATCH_BUT_PSK_NOT_USABLE; |
| } |
| #endif /* MBEDTLS_SSL_SESSION_TICKETS */ |
| |
| /* Check identity with external configured function */ |
| if (ssl->conf->f_psk != NULL) { |
| if (ssl->conf->f_psk( |
| ssl->conf->p_psk, ssl, identity, identity_len) == 0) { |
| return SSL_TLS1_3_PSK_IDENTITY_MATCH; |
| } |
| return SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; |
| } |
| |
| MBEDTLS_SSL_DEBUG_BUF(5, "identity", identity, identity_len); |
| /* Check identity with pre-configured psk */ |
| if (ssl->conf->psk_identity != NULL && |
| identity_len == ssl->conf->psk_identity_len && |
| mbedtls_ct_memcmp(ssl->conf->psk_identity, |
| identity, identity_len) == 0) { |
| ret = mbedtls_ssl_set_hs_psk(ssl, ssl->conf->psk, ssl->conf->psk_len); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_set_hs_psk", ret); |
| return ret; |
| } |
| return SSL_TLS1_3_PSK_IDENTITY_MATCH; |
| } |
| |
| return SSL_TLS1_3_PSK_IDENTITY_DOES_NOT_MATCH; |
| } |
| |
| /* |
| * Non-error return values of ssl_tls13_offered_psks_check_binder_match(). |
| * They are positive to not collide with error codes that are negative. Zero |
| * (SSL_TLS1_3_BINDER_MATCH) in case of success as it may be propagated up |
| * by the callers of this function as a generic success condition. |
| */ |
| #define SSL_TLS1_3_BINDER_DOES_NOT_MATCH 1 |
| #define SSL_TLS1_3_BINDER_MATCH 0 |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_offered_psks_check_binder_match( |
| mbedtls_ssl_context *ssl, |
| const unsigned char *binder, size_t binder_len, |
| int psk_type, psa_algorithm_t psk_hash_alg) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| unsigned char transcript[PSA_HASH_MAX_SIZE]; |
| size_t transcript_len; |
| unsigned char *psk; |
| size_t psk_len; |
| unsigned char server_computed_binder[PSA_HASH_MAX_SIZE]; |
| |
| /* Get current state of handshake transcript. */ |
| ret = mbedtls_ssl_get_handshake_transcript( |
| ssl, mbedtls_md_type_from_psa_alg(psk_hash_alg), |
| transcript, sizeof(transcript), &transcript_len); |
| if (ret != 0) { |
| return ret; |
| } |
| |
| ret = mbedtls_ssl_tls13_export_handshake_psk(ssl, &psk, &psk_len); |
| if (ret != 0) { |
| return ret; |
| } |
| |
| ret = mbedtls_ssl_tls13_create_psk_binder(ssl, psk_hash_alg, |
| psk, psk_len, psk_type, |
| transcript, |
| server_computed_binder); |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| mbedtls_free((void *) psk); |
| #endif |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("PSK binder calculation failed.")); |
| return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; |
| } |
| |
| MBEDTLS_SSL_DEBUG_BUF(3, "psk binder ( computed ): ", |
| server_computed_binder, transcript_len); |
| MBEDTLS_SSL_DEBUG_BUF(3, "psk binder ( received ): ", binder, binder_len); |
| |
| if (mbedtls_ct_memcmp(server_computed_binder, binder, binder_len) == 0) { |
| return SSL_TLS1_3_BINDER_MATCH; |
| } |
| |
| mbedtls_platform_zeroize(server_computed_binder, |
| sizeof(server_computed_binder)); |
| return SSL_TLS1_3_BINDER_DOES_NOT_MATCH; |
| } |
| |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_session_copy_ticket(mbedtls_ssl_session *dst, |
| const mbedtls_ssl_session *src) |
| { |
| dst->ticket_age_add = src->ticket_age_add; |
| dst->ticket_flags = src->ticket_flags; |
| dst->resumption_key_len = src->resumption_key_len; |
| if (src->resumption_key_len == 0) { |
| return MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| } |
| memcpy(dst->resumption_key, src->resumption_key, src->resumption_key_len); |
| |
| #if defined(MBEDTLS_SSL_EARLY_DATA) |
| dst->max_early_data_size = src->max_early_data_size; |
| #endif |
| |
| return 0; |
| } |
| #endif /* MBEDTLS_SSL_SESSION_TICKETS */ |
| |
| struct psk_attributes { |
| int type; |
| int key_exchange_mode; |
| const mbedtls_ssl_ciphersuite_t *ciphersuite_info; |
| }; |
| #define PSK_ATTRIBUTES_INIT { 0, 0, NULL } |
| |
| /* Parser for pre_shared_key extension in client hello |
| * struct { |
| * opaque identity<1..2^16-1>; |
| * uint32 obfuscated_ticket_age; |
| * } PskIdentity; |
| * |
| * opaque PskBinderEntry<32..255>; |
| * |
| * struct { |
| * PskIdentity identities<7..2^16-1>; |
| * PskBinderEntry binders<33..2^16-1>; |
| * } OfferedPsks; |
| * |
| * struct { |
| * select (Handshake.msg_type) { |
| * case client_hello: OfferedPsks; |
| * .... |
| * }; |
| * } PreSharedKeyExtension; |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_parse_pre_shared_key_ext( |
| mbedtls_ssl_context *ssl, |
| const unsigned char *pre_shared_key_ext, |
| const unsigned char *pre_shared_key_ext_end, |
| const unsigned char *ciphersuites, |
| const unsigned char *ciphersuites_end, |
| struct psk_attributes *psk) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| const unsigned char *identities = pre_shared_key_ext; |
| const unsigned char *p_identity_len; |
| size_t identities_len; |
| const unsigned char *identities_end; |
| const unsigned char *binders; |
| const unsigned char *p_binder_len; |
| size_t binders_len; |
| const unsigned char *binders_end; |
| int matched_identity = -1; |
| int identity_id = -1; |
| |
| MBEDTLS_SSL_DEBUG_BUF(3, "pre_shared_key extension", |
| pre_shared_key_ext, |
| pre_shared_key_ext_end - pre_shared_key_ext); |
| |
| /* identities_len 2 bytes |
| * identities_data >= 7 bytes |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(identities, pre_shared_key_ext_end, 7 + 2); |
| identities_len = MBEDTLS_GET_UINT16_BE(identities, 0); |
| p_identity_len = identities + 2; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p_identity_len, pre_shared_key_ext_end, |
| identities_len); |
| identities_end = p_identity_len + identities_len; |
| |
| /* binders_len 2 bytes |
| * binders >= 33 bytes |
| */ |
| binders = identities_end; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(binders, pre_shared_key_ext_end, 33 + 2); |
| binders_len = MBEDTLS_GET_UINT16_BE(binders, 0); |
| p_binder_len = binders + 2; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p_binder_len, pre_shared_key_ext_end, binders_len); |
| binders_end = p_binder_len + binders_len; |
| |
| ret = ssl->handshake->update_checksum(ssl, pre_shared_key_ext, |
| identities_end - pre_shared_key_ext); |
| if (0 != ret) { |
| MBEDTLS_SSL_DEBUG_RET(1, ("update_checksum"), ret); |
| return ret; |
| } |
| |
| while (p_identity_len < identities_end && p_binder_len < binders_end) { |
| const unsigned char *identity; |
| size_t identity_len; |
| uint32_t obfuscated_ticket_age; |
| const unsigned char *binder; |
| size_t binder_len; |
| int psk_ciphersuite_id; |
| psa_algorithm_t psk_hash_alg; |
| int allowed_key_exchange_modes; |
| |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| mbedtls_ssl_session session; |
| mbedtls_ssl_session_init(&session); |
| #endif |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p_identity_len, identities_end, 2 + 1 + 4); |
| identity_len = MBEDTLS_GET_UINT16_BE(p_identity_len, 0); |
| identity = p_identity_len + 2; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(identity, identities_end, identity_len + 4); |
| obfuscated_ticket_age = MBEDTLS_GET_UINT32_BE(identity, identity_len); |
| p_identity_len += identity_len + 6; |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p_binder_len, binders_end, 1 + 32); |
| binder_len = *p_binder_len; |
| binder = p_binder_len + 1; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(binder, binders_end, binder_len); |
| p_binder_len += binder_len + 1; |
| |
| identity_id++; |
| if (matched_identity != -1) { |
| continue; |
| } |
| |
| ret = ssl_tls13_offered_psks_check_identity_match( |
| ssl, identity, identity_len, obfuscated_ticket_age, |
| &psk->type, &session); |
| if (ret != SSL_TLS1_3_PSK_IDENTITY_MATCH) { |
| continue; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG(4, ("found matched identity")); |
| |
| switch (psk->type) { |
| case MBEDTLS_SSL_TLS1_3_PSK_EXTERNAL: |
| psk_ciphersuite_id = 0; |
| psk_hash_alg = PSA_ALG_SHA_256; |
| allowed_key_exchange_modes = |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL; |
| break; |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| case MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION: |
| psk_ciphersuite_id = session.ciphersuite; |
| psk_hash_alg = PSA_ALG_NONE; |
| ssl->session_negotiate->ticket_flags = session.ticket_flags; |
| allowed_key_exchange_modes = |
| session.ticket_flags & |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL; |
| break; |
| #endif |
| default: |
| return MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| } |
| |
| psk->key_exchange_mode = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_NONE; |
| |
| if ((allowed_key_exchange_modes & |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL) && |
| ssl_tls13_key_exchange_is_psk_ephemeral_available(ssl)) { |
| psk->key_exchange_mode = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL; |
| } else if ((allowed_key_exchange_modes & |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK) && |
| ssl_tls13_key_exchange_is_psk_available(ssl)) { |
| psk->key_exchange_mode = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK; |
| } |
| |
| if (psk->key_exchange_mode == MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_NONE) { |
| MBEDTLS_SSL_DEBUG_MSG(3, ("No suitable PSK key exchange mode")); |
| continue; |
| } |
| |
| ssl_tls13_select_ciphersuite(ssl, ciphersuites, ciphersuites_end, |
| psk_ciphersuite_id, psk_hash_alg, |
| &psk->ciphersuite_info); |
| |
| if (psk->ciphersuite_info == NULL) { |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| mbedtls_ssl_session_free(&session); |
| #endif |
| /* |
| * We consider finding a ciphersuite suitable for the PSK as part |
| * of the validation of its binder. Thus if we do not find one, we |
| * abort the handshake with a decrypt_error alert. |
| */ |
| MBEDTLS_SSL_PEND_FATAL_ALERT( |
| MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); |
| return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; |
| } |
| |
| ret = ssl_tls13_offered_psks_check_binder_match( |
| ssl, binder, binder_len, psk->type, |
| mbedtls_md_psa_alg_from_type((mbedtls_md_type_t) psk->ciphersuite_info->mac)); |
| if (ret != SSL_TLS1_3_BINDER_MATCH) { |
| /* For security reasons, the handshake should be aborted when we |
| * fail to validate a binder value. See RFC 8446 section 4.2.11.2 |
| * and appendix E.6. */ |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| mbedtls_ssl_session_free(&session); |
| #endif |
| MBEDTLS_SSL_DEBUG_MSG(3, ("Invalid binder.")); |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "ssl_tls13_offered_psks_check_binder_match", ret); |
| MBEDTLS_SSL_PEND_FATAL_ALERT( |
| MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); |
| return ret; |
| } |
| |
| matched_identity = identity_id; |
| |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| if (psk->type == MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION) { |
| ret = ssl_tls13_session_copy_ticket(ssl->session_negotiate, |
| &session); |
| mbedtls_ssl_session_free(&session); |
| if (ret != 0) { |
| return ret; |
| } |
| } |
| #endif /* MBEDTLS_SSL_SESSION_TICKETS */ |
| } |
| |
| if (p_identity_len != identities_end || p_binder_len != binders_end) { |
| MBEDTLS_SSL_DEBUG_MSG(3, ("pre_shared_key extension decode error")); |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, |
| MBEDTLS_ERR_SSL_DECODE_ERROR); |
| return MBEDTLS_ERR_SSL_DECODE_ERROR; |
| } |
| |
| /* Update the handshake transcript with the binder list. */ |
| ret = ssl->handshake->update_checksum( |
| ssl, identities_end, (size_t) (binders_end - identities_end)); |
| if (0 != ret) { |
| MBEDTLS_SSL_DEBUG_RET(1, ("update_checksum"), ret); |
| return ret; |
| } |
| if (matched_identity == -1) { |
| MBEDTLS_SSL_DEBUG_MSG(3, ("No usable PSK or ticket.")); |
| return MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY; |
| } |
| |
| ssl->handshake->selected_identity = (uint16_t) matched_identity; |
| MBEDTLS_SSL_DEBUG_MSG(3, ("Pre shared key found")); |
| |
| return 0; |
| } |
| |
| /* |
| * struct { |
| * select ( Handshake.msg_type ) { |
| * .... |
| * case server_hello: |
| * uint16 selected_identity; |
| * } |
| * } PreSharedKeyExtension; |
| */ |
| static int ssl_tls13_write_server_pre_shared_key_ext(mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *olen) |
| { |
| unsigned char *p = (unsigned char *) buf; |
| |
| *olen = 0; |
| |
| int not_using_psk = 0; |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| not_using_psk = (mbedtls_svc_key_id_is_null(ssl->handshake->psk_opaque)); |
| #else |
| not_using_psk = (ssl->handshake->psk == NULL); |
| #endif |
| if (not_using_psk) { |
| /* We shouldn't have called this extension writer unless we've |
| * chosen to use a PSK. */ |
| return MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding pre_shared_key extension")); |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 6); |
| |
| MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_PRE_SHARED_KEY, p, 0); |
| MBEDTLS_PUT_UINT16_BE(2, p, 2); |
| |
| MBEDTLS_PUT_UINT16_BE(ssl->handshake->selected_identity, p, 4); |
| |
| *olen = 6; |
| |
| MBEDTLS_SSL_DEBUG_MSG(4, ("sent selected_identity: %u", |
| ssl->handshake->selected_identity)); |
| |
| mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_PRE_SHARED_KEY); |
| |
| return 0; |
| } |
| |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */ |
| |
| /* From RFC 8446: |
| * struct { |
| * ProtocolVersion versions<2..254>; |
| * } SupportedVersions; |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_parse_supported_versions_ext(mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end) |
| { |
| const unsigned char *p = buf; |
| size_t versions_len; |
| const unsigned char *versions_end; |
| uint16_t tls_version; |
| int found_supported_version = 0; |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 1); |
| versions_len = p[0]; |
| p += 1; |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, versions_len); |
| versions_end = p + versions_len; |
| while (p < versions_end) { |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, versions_end, 2); |
| tls_version = mbedtls_ssl_read_version(p, ssl->conf->transport); |
| p += 2; |
| |
| if (MBEDTLS_SSL_VERSION_TLS1_3 == tls_version) { |
| found_supported_version = 1; |
| break; |
| } |
| |
| if ((MBEDTLS_SSL_VERSION_TLS1_2 == tls_version) && |
| mbedtls_ssl_conf_is_tls12_enabled(ssl->conf)) { |
| found_supported_version = 1; |
| break; |
| } |
| } |
| |
| if (!found_supported_version) { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("No supported version found.")); |
| |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION, |
| MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION); |
| return MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG(1, ("Negotiated version: [%04x]", |
| (unsigned int) tls_version)); |
| |
| return (int) tls_version; |
| } |
| |
| #if defined(PSA_WANT_ALG_ECDH) || defined(PSA_WANT_ALG_FFDH) |
| /* |
| * |
| * From RFC 8446: |
| * enum { |
| * ... (0xFFFF) |
| * } NamedGroup; |
| * struct { |
| * NamedGroup named_group_list<2..2^16-1>; |
| * } NamedGroupList; |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_parse_supported_groups_ext(mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end) |
| { |
| const unsigned char *p = buf; |
| size_t named_group_list_len; |
| const unsigned char *named_group_list_end; |
| |
| MBEDTLS_SSL_DEBUG_BUF(3, "supported_groups extension", p, end - buf); |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2); |
| named_group_list_len = MBEDTLS_GET_UINT16_BE(p, 0); |
| p += 2; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, named_group_list_len); |
| named_group_list_end = p + named_group_list_len; |
| ssl->handshake->hrr_selected_group = 0; |
| |
| while (p < named_group_list_end) { |
| uint16_t named_group; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, named_group_list_end, 2); |
| named_group = MBEDTLS_GET_UINT16_BE(p, 0); |
| p += 2; |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, |
| ("got named group: %s(%04x)", |
| mbedtls_ssl_named_group_to_str(named_group), |
| named_group)); |
| |
| if (!mbedtls_ssl_named_group_is_offered(ssl, named_group) || |
| !mbedtls_ssl_named_group_is_supported(named_group) || |
| ssl->handshake->hrr_selected_group != 0) { |
| continue; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, |
| ("add named group %s(%04x) into received list.", |
| mbedtls_ssl_named_group_to_str(named_group), |
| named_group)); |
| |
| ssl->handshake->hrr_selected_group = named_group; |
| } |
| |
| return 0; |
| |
| } |
| #endif /* PSA_WANT_ALG_ECDH || PSA_WANT_ALG_FFDH */ |
| |
| #define SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH 1 |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED) |
| /* |
| * ssl_tls13_parse_key_shares_ext() verifies whether the information in the |
| * extension is correct and stores the first acceptable key share and its |
| * associated group. |
| * |
| * Possible return values are: |
| * - 0: Successful processing of the client provided key share extension. |
| * - SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH: The key shares provided by |
| * the client does not match a group supported by the server. A |
| * HelloRetryRequest will be needed. |
| * - A negative value for fatal errors. |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_parse_key_shares_ext(mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char const *p = buf; |
| unsigned char const *client_shares_end; |
| size_t client_shares_len; |
| |
| /* From RFC 8446: |
| * |
| * struct { |
| * KeyShareEntry client_shares<0..2^16-1>; |
| * } KeyShareClientHello; |
| * |
| */ |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2); |
| client_shares_len = MBEDTLS_GET_UINT16_BE(p, 0); |
| p += 2; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, client_shares_len); |
| |
| ssl->handshake->offered_group_id = 0; |
| client_shares_end = p + client_shares_len; |
| |
| /* We try to find a suitable key share entry and copy it to the |
| * handshake context. Later, we have to find out whether we can do |
| * something with the provided key share or whether we have to |
| * dismiss it and send a HelloRetryRequest message. |
| */ |
| |
| while (p < client_shares_end) { |
| uint16_t group; |
| size_t key_exchange_len; |
| const unsigned char *key_exchange; |
| |
| /* |
| * struct { |
| * NamedGroup group; |
| * opaque key_exchange<1..2^16-1>; |
| * } KeyShareEntry; |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, client_shares_end, 4); |
| group = MBEDTLS_GET_UINT16_BE(p, 0); |
| key_exchange_len = MBEDTLS_GET_UINT16_BE(p, 2); |
| p += 4; |
| key_exchange = p; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, client_shares_end, key_exchange_len); |
| p += key_exchange_len; |
| |
| /* Continue parsing even if we have already found a match, |
| * for input validation purposes. |
| */ |
| if (!mbedtls_ssl_named_group_is_offered(ssl, group) || |
| !mbedtls_ssl_named_group_is_supported(group) || |
| ssl->handshake->offered_group_id != 0) { |
| continue; |
| } |
| |
| /* |
| * ECDHE and FFDHE groups are supported |
| */ |
| if (mbedtls_ssl_tls13_named_group_is_ecdhe(group) || |
| mbedtls_ssl_tls13_named_group_is_ffdh(group)) { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("ECDH/FFDH group: %s (%04x)", |
| mbedtls_ssl_named_group_to_str(group), |
| group)); |
| ret = mbedtls_ssl_tls13_read_public_xxdhe_share( |
| ssl, key_exchange - 2, key_exchange_len + 2); |
| if (ret != 0) { |
| return ret; |
| } |
| |
| } else { |
| MBEDTLS_SSL_DEBUG_MSG(4, ("Unrecognized NamedGroup %u", |
| (unsigned) group)); |
| continue; |
| } |
| |
| ssl->handshake->offered_group_id = group; |
| } |
| |
| |
| if (ssl->handshake->offered_group_id == 0) { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("no matching key share")); |
| return SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH; |
| } |
| return 0; |
| } |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */ |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_client_hello_has_exts(mbedtls_ssl_context *ssl, |
| int exts_mask) |
| { |
| int masked = ssl->handshake->received_extensions & exts_mask; |
| return masked == exts_mask; |
| } |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_client_hello_has_exts_for_ephemeral_key_exchange( |
| mbedtls_ssl_context *ssl) |
| { |
| return ssl_tls13_client_hello_has_exts( |
| ssl, |
| MBEDTLS_SSL_EXT_MASK(SUPPORTED_GROUPS) | |
| MBEDTLS_SSL_EXT_MASK(KEY_SHARE) | |
| MBEDTLS_SSL_EXT_MASK(SIG_ALG)); |
| } |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ENABLED) |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_client_hello_has_exts_for_psk_key_exchange( |
| mbedtls_ssl_context *ssl) |
| { |
| return ssl_tls13_client_hello_has_exts( |
| ssl, |
| MBEDTLS_SSL_EXT_MASK(PRE_SHARED_KEY) | |
| MBEDTLS_SSL_EXT_MASK(PSK_KEY_EXCHANGE_MODES)); |
| } |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ENABLED */ |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED) |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_client_hello_has_exts_for_psk_ephemeral_key_exchange( |
| mbedtls_ssl_context *ssl) |
| { |
| return ssl_tls13_client_hello_has_exts( |
| ssl, |
| MBEDTLS_SSL_EXT_MASK(SUPPORTED_GROUPS) | |
| MBEDTLS_SSL_EXT_MASK(KEY_SHARE) | |
| MBEDTLS_SSL_EXT_MASK(PRE_SHARED_KEY) | |
| MBEDTLS_SSL_EXT_MASK(PSK_KEY_EXCHANGE_MODES)); |
| } |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED */ |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_key_exchange_is_psk_available(mbedtls_ssl_context *ssl) |
| { |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ENABLED) |
| return mbedtls_ssl_conf_tls13_is_psk_enabled(ssl) && |
| mbedtls_ssl_tls13_is_psk_supported(ssl) && |
| ssl_tls13_client_hello_has_exts_for_psk_key_exchange(ssl); |
| #else |
| ((void) ssl); |
| return 0; |
| #endif |
| } |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_key_exchange_is_psk_ephemeral_available(mbedtls_ssl_context *ssl) |
| { |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED) |
| return mbedtls_ssl_conf_tls13_is_psk_ephemeral_enabled(ssl) && |
| mbedtls_ssl_tls13_is_psk_ephemeral_supported(ssl) && |
| ssl_tls13_client_hello_has_exts_for_psk_ephemeral_key_exchange(ssl); |
| #else |
| ((void) ssl); |
| return 0; |
| #endif |
| } |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */ |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_key_exchange_is_ephemeral_available(mbedtls_ssl_context *ssl) |
| { |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) |
| return mbedtls_ssl_conf_tls13_is_ephemeral_enabled(ssl) && |
| ssl_tls13_client_hello_has_exts_for_ephemeral_key_exchange(ssl); |
| #else |
| ((void) ssl); |
| return 0; |
| #endif |
| } |
| |
| #if defined(MBEDTLS_X509_CRT_PARSE_C) && \ |
| defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| static psa_algorithm_t ssl_tls13_iana_sig_alg_to_psa_alg(uint16_t sig_alg) |
| { |
| switch (sig_alg) { |
| case MBEDTLS_TLS1_3_SIG_ECDSA_SECP256R1_SHA256: |
| return PSA_ALG_ECDSA(PSA_ALG_SHA_256); |
| case MBEDTLS_TLS1_3_SIG_ECDSA_SECP384R1_SHA384: |
| return PSA_ALG_ECDSA(PSA_ALG_SHA_384); |
| case MBEDTLS_TLS1_3_SIG_ECDSA_SECP521R1_SHA512: |
| return PSA_ALG_ECDSA(PSA_ALG_SHA_512); |
| case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256: |
| return PSA_ALG_RSA_PSS(PSA_ALG_SHA_256); |
| case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384: |
| return PSA_ALG_RSA_PSS(PSA_ALG_SHA_384); |
| case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512: |
| return PSA_ALG_RSA_PSS(PSA_ALG_SHA_512); |
| case MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA256: |
| return PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_SHA_256); |
| case MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA384: |
| return PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_SHA_384); |
| case MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA512: |
| return PSA_ALG_RSA_PKCS1V15_SIGN(PSA_ALG_SHA_512); |
| default: |
| return PSA_ALG_NONE; |
| } |
| } |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| /* |
| * Pick best ( private key, certificate chain ) pair based on the signature |
| * algorithms supported by the client. |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_pick_key_cert(mbedtls_ssl_context *ssl) |
| { |
| mbedtls_ssl_key_cert *key_cert, *key_cert_list; |
| const uint16_t *sig_alg = ssl->handshake->received_sig_algs; |
| |
| #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) |
| if (ssl->handshake->sni_key_cert != NULL) { |
| key_cert_list = ssl->handshake->sni_key_cert; |
| } else |
| #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ |
| key_cert_list = ssl->conf->key_cert; |
| |
| if (key_cert_list == NULL) { |
| MBEDTLS_SSL_DEBUG_MSG(3, ("server has no certificate")); |
| return -1; |
| } |
| |
| for (; *sig_alg != MBEDTLS_TLS1_3_SIG_NONE; sig_alg++) { |
| if (!mbedtls_ssl_sig_alg_is_offered(ssl, *sig_alg)) { |
| continue; |
| } |
| |
| if (!mbedtls_ssl_tls13_sig_alg_for_cert_verify_is_supported(*sig_alg)) { |
| continue; |
| } |
| |
| for (key_cert = key_cert_list; key_cert != NULL; |
| key_cert = key_cert->next) { |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_algorithm_t psa_alg = PSA_ALG_NONE; |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| MBEDTLS_SSL_DEBUG_CRT(3, "certificate (chain) candidate", |
| key_cert->cert); |
| |
| /* |
| * This avoids sending the client a cert it'll reject based on |
| * keyUsage or other extensions. |
| */ |
| if (mbedtls_x509_crt_check_key_usage( |
| key_cert->cert, MBEDTLS_X509_KU_DIGITAL_SIGNATURE) != 0 || |
| mbedtls_x509_crt_check_extended_key_usage( |
| key_cert->cert, MBEDTLS_OID_SERVER_AUTH, |
| MBEDTLS_OID_SIZE(MBEDTLS_OID_SERVER_AUTH)) != 0) { |
| MBEDTLS_SSL_DEBUG_MSG(3, ("certificate mismatch: " |
| "(extended) key usage extension")); |
| continue; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG(3, |
| ("ssl_tls13_pick_key_cert:" |
| "check signature algorithm %s [%04x]", |
| mbedtls_ssl_sig_alg_to_str(*sig_alg), |
| *sig_alg)); |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_alg = ssl_tls13_iana_sig_alg_to_psa_alg(*sig_alg); |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| if (mbedtls_ssl_tls13_check_sig_alg_cert_key_match( |
| *sig_alg, &key_cert->cert->pk) |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| && psa_alg != PSA_ALG_NONE && |
| mbedtls_pk_can_do_ext(&key_cert->cert->pk, psa_alg, |
| PSA_KEY_USAGE_SIGN_HASH) == 1 |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| ) { |
| ssl->handshake->key_cert = key_cert; |
| MBEDTLS_SSL_DEBUG_MSG(3, |
| ("ssl_tls13_pick_key_cert:" |
| "selected signature algorithm" |
| " %s [%04x]", |
| mbedtls_ssl_sig_alg_to_str(*sig_alg), |
| *sig_alg)); |
| MBEDTLS_SSL_DEBUG_CRT( |
| 3, "selected certificate (chain)", |
| ssl->handshake->key_cert->cert); |
| return 0; |
| } |
| } |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("ssl_tls13_pick_key_cert:" |
| "no suitable certificate found")); |
| return -1; |
| } |
| #endif /* MBEDTLS_X509_CRT_PARSE_C && |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ |
| |
| /* |
| * |
| * STATE HANDLING: ClientHello |
| * |
| * There are three possible classes of outcomes when parsing the ClientHello: |
| * |
| * 1) The ClientHello was well-formed and matched the server's configuration. |
| * |
| * In this case, the server progresses to sending its ServerHello. |
| * |
| * 2) The ClientHello was well-formed but didn't match the server's |
| * configuration. |
| * |
| * For example, the client might not have offered a key share which |
| * the server supports, or the server might require a cookie. |
| * |
| * In this case, the server sends a HelloRetryRequest. |
| * |
| * 3) The ClientHello was ill-formed |
| * |
| * In this case, we abort the handshake. |
| * |
| */ |
| |
| /* |
| * Structure of this message: |
| * |
| * uint16 ProtocolVersion; |
| * opaque Random[32]; |
| * uint8 CipherSuite[2]; // Cryptographic suite selector |
| * |
| * struct { |
| * ProtocolVersion legacy_version = 0x0303; // TLS v1.2 |
| * Random random; |
| * opaque legacy_session_id<0..32>; |
| * CipherSuite cipher_suites<2..2^16-2>; |
| * opaque legacy_compression_methods<1..2^8-1>; |
| * Extension extensions<8..2^16-1>; |
| * } ClientHello; |
| */ |
| |
| #define SSL_CLIENT_HELLO_OK 0 |
| #define SSL_CLIENT_HELLO_HRR_REQUIRED 1 |
| #define SSL_CLIENT_HELLO_TLS1_2 2 |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_parse_client_hello(mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| const unsigned char *p = buf; |
| const unsigned char *random; |
| size_t legacy_session_id_len; |
| const unsigned char *legacy_session_id; |
| size_t cipher_suites_len; |
| const unsigned char *cipher_suites; |
| const unsigned char *cipher_suites_end; |
| size_t extensions_len; |
| const unsigned char *extensions_end; |
| const unsigned char *supported_versions_data; |
| const unsigned char *supported_versions_data_end; |
| mbedtls_ssl_handshake_params *handshake = ssl->handshake; |
| int hrr_required = 0; |
| int no_usable_share_for_key_agreement = 0; |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| int got_psk = 0; |
| struct psk_attributes psk = PSK_ATTRIBUTES_INIT; |
| const unsigned char *pre_shared_key_ext = NULL; |
| const unsigned char *pre_shared_key_ext_end = NULL; |
| #endif |
| |
| /* |
| * ClientHello layout: |
| * 0 . 1 protocol version |
| * 2 . 33 random bytes |
| * 34 . 34 session id length ( 1 byte ) |
| * 35 . 34+x session id |
| * .. . .. ciphersuite list length ( 2 bytes ) |
| * .. . .. ciphersuite list |
| * .. . .. compression alg. list length ( 1 byte ) |
| * .. . .. compression alg. list |
| * .. . .. extensions length ( 2 bytes, optional ) |
| * .. . .. extensions ( optional ) |
| */ |
| |
| /* |
| * Minimal length ( with everything empty and extensions omitted ) is |
| * 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can |
| * read at least up to session id length without worrying. |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 38); |
| |
| /* ... |
| * ProtocolVersion legacy_version = 0x0303; // TLS 1.2 |
| * ... |
| * with ProtocolVersion defined as: |
| * uint16 ProtocolVersion; |
| */ |
| if (mbedtls_ssl_read_version(p, ssl->conf->transport) != |
| MBEDTLS_SSL_VERSION_TLS1_2) { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("Unsupported version of TLS.")); |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION, |
| MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION); |
| return MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION; |
| } |
| p += 2; |
| |
| /* ... |
| * Random random; |
| * ... |
| * with Random defined as: |
| * opaque Random[32]; |
| */ |
| random = p; |
| p += MBEDTLS_CLIENT_HELLO_RANDOM_LEN; |
| |
| /* ... |
| * opaque legacy_session_id<0..32>; |
| * ... |
| */ |
| legacy_session_id_len = *(p++); |
| legacy_session_id = p; |
| |
| /* |
| * Check we have enough data for the legacy session identifier |
| * and the ciphersuite list length. |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, legacy_session_id_len + 2); |
| p += legacy_session_id_len; |
| |
| /* ... |
| * CipherSuite cipher_suites<2..2^16-2>; |
| * ... |
| * with CipherSuite defined as: |
| * uint8 CipherSuite[2]; |
| */ |
| cipher_suites_len = MBEDTLS_GET_UINT16_BE(p, 0); |
| p += 2; |
| cipher_suites = p; |
| |
| /* |
| * The length of the ciphersuite list has to be even. |
| */ |
| if (cipher_suites_len & 1) { |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, |
| MBEDTLS_ERR_SSL_DECODE_ERROR); |
| return MBEDTLS_ERR_SSL_DECODE_ERROR; |
| } |
| |
| /* Check we have enough data for the ciphersuite list, the legacy |
| * compression methods and the length of the extensions. |
| * |
| * cipher_suites cipher_suites_len bytes |
| * legacy_compression_methods 2 bytes |
| * extensions_len 2 bytes |
| */ |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, cipher_suites_len + 2 + 2); |
| p += cipher_suites_len; |
| cipher_suites_end = p; |
| |
| /* |
| * Search for the supported versions extension and parse it to determine |
| * if the client supports TLS 1.3. |
| */ |
| ret = mbedtls_ssl_tls13_is_supported_versions_ext_present_in_exts( |
| ssl, p + 2, end, |
| &supported_versions_data, &supported_versions_data_end); |
| if (ret < 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, |
| ("mbedtls_ssl_tls13_is_supported_versions_ext_present_in_exts"), ret); |
| return ret; |
| } |
| |
| if (ret == 0) { |
| return SSL_CLIENT_HELLO_TLS1_2; |
| } |
| |
| if (ret == 1) { |
| ret = ssl_tls13_parse_supported_versions_ext(ssl, |
| supported_versions_data, |
| supported_versions_data_end); |
| if (ret < 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, |
| ("ssl_tls13_parse_supported_versions_ext"), ret); |
| return ret; |
| } |
| |
| /* |
| * The supported versions extension was parsed successfully as the |
| * value returned by ssl_tls13_parse_supported_versions_ext() is |
| * positive. The return value is then equal to |
| * MBEDTLS_SSL_VERSION_TLS1_2 or MBEDTLS_SSL_VERSION_TLS1_3, defining |
| * the TLS version to negotiate. |
| */ |
| if (MBEDTLS_SSL_VERSION_TLS1_2 == ret) { |
| return SSL_CLIENT_HELLO_TLS1_2; |
| } |
| } |
| |
| /* |
| * We negotiate TLS 1.3. |
| */ |
| ssl->tls_version = MBEDTLS_SSL_VERSION_TLS1_3; |
| ssl->session_negotiate->tls_version = MBEDTLS_SSL_VERSION_TLS1_3; |
| ssl->session_negotiate->endpoint = ssl->conf->endpoint; |
| |
| /* |
| * We are negotiating the version 1.3 of the protocol. Do what we have |
| * postponed: copy of the client random bytes, copy of the legacy session |
| * identifier and selection of the TLS 1.3 cipher suite. |
| */ |
| MBEDTLS_SSL_DEBUG_BUF(3, "client hello, random bytes", |
| random, MBEDTLS_CLIENT_HELLO_RANDOM_LEN); |
| memcpy(&handshake->randbytes[0], random, MBEDTLS_CLIENT_HELLO_RANDOM_LEN); |
| |
| if (legacy_session_id_len > sizeof(ssl->session_negotiate->id)) { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); |
| return MBEDTLS_ERR_SSL_DECODE_ERROR; |
| } |
| ssl->session_negotiate->id_len = legacy_session_id_len; |
| MBEDTLS_SSL_DEBUG_BUF(3, "client hello, session id", |
| legacy_session_id, legacy_session_id_len); |
| memcpy(&ssl->session_negotiate->id[0], |
| legacy_session_id, legacy_session_id_len); |
| |
| /* |
| * Search for a matching ciphersuite |
| */ |
| MBEDTLS_SSL_DEBUG_BUF(3, "client hello, list of cipher suites", |
| cipher_suites, cipher_suites_len); |
| |
| ssl_tls13_select_ciphersuite(ssl, cipher_suites, cipher_suites_end, |
| 0, PSA_ALG_NONE, &handshake->ciphersuite_info); |
| |
| if (handshake->ciphersuite_info == NULL) { |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); |
| return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; |
| } |
| ssl->session_negotiate->ciphersuite = handshake->ciphersuite_info->id; |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("selected ciphersuite: %04x - %s", |
| ((unsigned) handshake->ciphersuite_info->id), |
| handshake->ciphersuite_info->name)); |
| |
| /* ... |
| * opaque legacy_compression_methods<1..2^8-1>; |
| * ... |
| */ |
| if (p[0] != 1 || p[1] != MBEDTLS_SSL_COMPRESS_NULL) { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("bad legacy compression method")); |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, |
| MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); |
| return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; |
| } |
| p += 2; |
| |
| /* ... |
| * Extension extensions<8..2^16-1>; |
| * ... |
| * with Extension defined as: |
| * struct { |
| * ExtensionType extension_type; |
| * opaque extension_data<0..2^16-1>; |
| * } Extension; |
| */ |
| extensions_len = MBEDTLS_GET_UINT16_BE(p, 0); |
| p += 2; |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, extensions_len); |
| extensions_end = p + extensions_len; |
| |
| MBEDTLS_SSL_DEBUG_BUF(3, "client hello extensions", p, extensions_len); |
| handshake->received_extensions = MBEDTLS_SSL_EXT_MASK_NONE; |
| |
| while (p < extensions_end) { |
| unsigned int extension_type; |
| size_t extension_data_len; |
| const unsigned char *extension_data_end; |
| uint32_t allowed_exts = MBEDTLS_SSL_TLS1_3_ALLOWED_EXTS_OF_CH; |
| |
| if (ssl->handshake->hello_retry_request_flag) { |
| /* Do not accept early data extension in 2nd ClientHello */ |
| allowed_exts &= ~MBEDTLS_SSL_EXT_MASK(EARLY_DATA); |
| } |
| |
| /* RFC 8446, section 4.2.11 |
| * |
| * The "pre_shared_key" extension MUST be the last extension in the |
| * ClientHello (this facilitates implementation as described below). |
| * Servers MUST check that it is the last extension and otherwise fail |
| * the handshake with an "illegal_parameter" alert. |
| */ |
| if (handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(PRE_SHARED_KEY)) { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 3, ("pre_shared_key is not last extension.")); |
| MBEDTLS_SSL_PEND_FATAL_ALERT( |
| MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, |
| MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); |
| return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; |
| } |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, 4); |
| extension_type = MBEDTLS_GET_UINT16_BE(p, 0); |
| extension_data_len = MBEDTLS_GET_UINT16_BE(p, 2); |
| p += 4; |
| |
| MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, extension_data_len); |
| extension_data_end = p + extension_data_len; |
| |
| ret = mbedtls_ssl_tls13_check_received_extension( |
| ssl, MBEDTLS_SSL_HS_CLIENT_HELLO, extension_type, |
| allowed_exts); |
| if (ret != 0) { |
| return ret; |
| } |
| |
| switch (extension_type) { |
| #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) |
| case MBEDTLS_TLS_EXT_SERVERNAME: |
| MBEDTLS_SSL_DEBUG_MSG(3, ("found ServerName extension")); |
| ret = mbedtls_ssl_parse_server_name_ext(ssl, p, |
| extension_data_end); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "mbedtls_ssl_parse_servername_ext", ret); |
| return ret; |
| } |
| break; |
| #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ |
| |
| #if defined(PSA_WANT_ALG_ECDH) || defined(PSA_WANT_ALG_FFDH) |
| case MBEDTLS_TLS_EXT_SUPPORTED_GROUPS: |
| MBEDTLS_SSL_DEBUG_MSG(3, ("found supported group extension")); |
| |
| /* Supported Groups Extension |
| * |
| * When sent by the client, the "supported_groups" extension |
| * indicates the named groups which the client supports, |
| * ordered from most preferred to least preferred. |
| */ |
| ret = ssl_tls13_parse_supported_groups_ext( |
| ssl, p, extension_data_end); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "ssl_tls13_parse_supported_groups_ext", ret); |
| return ret; |
| } |
| |
| break; |
| #endif /* PSA_WANT_ALG_ECDH || PSA_WANT_ALG_FFDH*/ |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED) |
| case MBEDTLS_TLS_EXT_KEY_SHARE: |
| MBEDTLS_SSL_DEBUG_MSG(3, ("found key share extension")); |
| |
| /* |
| * Key Share Extension |
| * |
| * When sent by the client, the "key_share" extension |
| * contains the endpoint's cryptographic parameters for |
| * ECDHE/DHE key establishment methods. |
| */ |
| ret = ssl_tls13_parse_key_shares_ext( |
| ssl, p, extension_data_end); |
| if (ret == SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH) { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("No usable share for key agreement.")); |
| no_usable_share_for_key_agreement = 1; |
| } |
| |
| if (ret < 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "ssl_tls13_parse_key_shares_ext", ret); |
| return ret; |
| } |
| |
| break; |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */ |
| |
| case MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS: |
| /* Already parsed */ |
| break; |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| case MBEDTLS_TLS_EXT_PSK_KEY_EXCHANGE_MODES: |
| MBEDTLS_SSL_DEBUG_MSG( |
| 3, ("found psk key exchange modes extension")); |
| |
| ret = ssl_tls13_parse_key_exchange_modes_ext( |
| ssl, p, extension_data_end); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "ssl_tls13_parse_key_exchange_modes_ext", ret); |
| return ret; |
| } |
| |
| break; |
| #endif |
| |
| case MBEDTLS_TLS_EXT_PRE_SHARED_KEY: |
| MBEDTLS_SSL_DEBUG_MSG(3, ("found pre_shared_key extension")); |
| if ((handshake->received_extensions & |
| MBEDTLS_SSL_EXT_MASK(PSK_KEY_EXCHANGE_MODES)) == 0) { |
| MBEDTLS_SSL_PEND_FATAL_ALERT( |
| MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER, |
| MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); |
| return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; |
| } |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| /* Delay processing of the PSK identity once we have |
| * found out which algorithms to use. We keep a pointer |
| * to the buffer and the size for later processing. |
| */ |
| pre_shared_key_ext = p; |
| pre_shared_key_ext_end = extension_data_end; |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */ |
| break; |
| |
| #if defined(MBEDTLS_SSL_ALPN) |
| case MBEDTLS_TLS_EXT_ALPN: |
| MBEDTLS_SSL_DEBUG_MSG(3, ("found alpn extension")); |
| |
| ret = mbedtls_ssl_parse_alpn_ext(ssl, p, extension_data_end); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, ("mbedtls_ssl_parse_alpn_ext"), ret); |
| return ret; |
| } |
| break; |
| #endif /* MBEDTLS_SSL_ALPN */ |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) |
| case MBEDTLS_TLS_EXT_SIG_ALG: |
| MBEDTLS_SSL_DEBUG_MSG(3, ("found signature_algorithms extension")); |
| |
| ret = mbedtls_ssl_parse_sig_alg_ext( |
| ssl, p, extension_data_end); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "mbedtls_ssl_parse_sig_alg_ext", ret); |
| return ret; |
| } |
| break; |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ |
| |
| #if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT) |
| case MBEDTLS_TLS_EXT_RECORD_SIZE_LIMIT: |
| MBEDTLS_SSL_DEBUG_MSG(3, ("found record_size_limit extension")); |
| |
| ret = mbedtls_ssl_tls13_parse_record_size_limit_ext( |
| ssl, p, extension_data_end); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, ("mbedtls_ssl_tls13_parse_record_size_limit_ext"), ret); |
| return ret; |
| } |
| break; |
| #endif /* MBEDTLS_SSL_RECORD_SIZE_LIMIT */ |
| |
| default: |
| MBEDTLS_SSL_PRINT_EXT( |
| 3, MBEDTLS_SSL_HS_CLIENT_HELLO, |
| extension_type, "( ignored )"); |
| break; |
| } |
| |
| p += extension_data_len; |
| } |
| |
| MBEDTLS_SSL_PRINT_EXTS(3, MBEDTLS_SSL_HS_CLIENT_HELLO, |
| handshake->received_extensions); |
| |
| ret = mbedtls_ssl_add_hs_hdr_to_checksum(ssl, |
| MBEDTLS_SSL_HS_CLIENT_HELLO, |
| p - buf); |
| if (0 != ret) { |
| MBEDTLS_SSL_DEBUG_RET(1, ("mbedtls_ssl_add_hs_hdr_to_checksum"), ret); |
| return ret; |
| } |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| /* Update checksum with either |
| * - The entire content of the CH message, if no PSK extension is present |
| * - The content up to but excluding the PSK extension, if present. |
| * Always parse the pre-shared-key extension when present in the |
| * ClientHello even if some pre-requisites for PSK key exchange modes are |
| * not met. That way we always validate the syntax of the extension. |
| */ |
| if (handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(PRE_SHARED_KEY)) { |
| ret = handshake->update_checksum(ssl, buf, |
| pre_shared_key_ext - buf); |
| if (0 != ret) { |
| MBEDTLS_SSL_DEBUG_RET(1, ("update_checksum"), ret); |
| return ret; |
| } |
| ret = ssl_tls13_parse_pre_shared_key_ext(ssl, |
| pre_shared_key_ext, |
| pre_shared_key_ext_end, |
| cipher_suites, |
| cipher_suites_end, |
| &psk); |
| if (ret == 0) { |
| got_psk = 1; |
| } else if (ret != MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "ssl_tls13_parse_pre_shared_key_ext", ret); |
| return ret; |
| } |
| } else |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */ |
| { |
| ret = handshake->update_checksum(ssl, buf, p - buf); |
| if (0 != ret) { |
| MBEDTLS_SSL_DEBUG_RET(1, ("update_checksum"), ret); |
| return ret; |
| } |
| } |
| |
| /* |
| * Determine the key exchange algorithm to use. |
| * There are three types of key exchanges supported in TLS 1.3: |
| * - (EC)DH with ECDSA, |
| * - (EC)DH with PSK, |
| * - plain PSK. |
| * |
| * The PSK-based key exchanges may additionally be used with 0-RTT. |
| * |
| * Our built-in order of preference is |
| * 1 ) (EC)DHE-PSK Mode ( psk_ephemeral ) |
| * 2 ) Certificate Mode ( ephemeral ) |
| * 3 ) Plain PSK Mode ( psk ) |
| */ |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| if (got_psk && (psk.key_exchange_mode == |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL)) { |
| handshake->key_exchange_mode = |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL; |
| MBEDTLS_SSL_DEBUG_MSG(2, ("key exchange mode: psk_ephemeral")); |
| |
| } else |
| #endif |
| if (ssl_tls13_key_exchange_is_ephemeral_available(ssl)) { |
| handshake->key_exchange_mode = |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL; |
| MBEDTLS_SSL_DEBUG_MSG(2, ("key exchange mode: ephemeral")); |
| |
| } |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| else if (got_psk && (psk.key_exchange_mode == |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK)) { |
| handshake->key_exchange_mode = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK; |
| MBEDTLS_SSL_DEBUG_MSG(2, ("key exchange mode: psk")); |
| } |
| #endif |
| else { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, |
| ("ClientHello message misses mandatory extensions.")); |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_MISSING_EXTENSION, |
| MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER); |
| return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER; |
| } |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| if (handshake->key_exchange_mode & |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL) { |
| handshake->ciphersuite_info = psk.ciphersuite_info; |
| ssl->session_negotiate->ciphersuite = psk.ciphersuite_info->id; |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("Select PSK ciphersuite: %04x - %s", |
| ((unsigned) psk.ciphersuite_info->id), |
| psk.ciphersuite_info->name)); |
| |
| if (psk.type == MBEDTLS_SSL_TLS1_3_PSK_RESUMPTION) { |
| handshake->resume = 1; |
| } |
| } |
| #endif |
| |
| if (handshake->key_exchange_mode != |
| MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK) { |
| hrr_required = (no_usable_share_for_key_agreement != 0); |
| } |
| |
| mbedtls_ssl_optimize_checksum(ssl, handshake->ciphersuite_info); |
| |
| return hrr_required ? SSL_CLIENT_HELLO_HRR_REQUIRED : SSL_CLIENT_HELLO_OK; |
| } |
| |
| #if defined(MBEDTLS_SSL_EARLY_DATA) |
| static int ssl_tls13_check_early_data_requirements(mbedtls_ssl_context *ssl) |
| { |
| mbedtls_ssl_handshake_params *handshake = ssl->handshake; |
| |
| if (ssl->conf->early_data_enabled == MBEDTLS_SSL_EARLY_DATA_DISABLED) { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, |
| ("EarlyData: rejected, feature disabled in server configuration.")); |
| return -1; |
| } |
| |
| if (!handshake->resume) { |
| /* We currently support early data only in the case of PSKs established |
| via a NewSessionTicket message thus in the case of a session |
| resumption. */ |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, ("EarlyData: rejected, not a session resumption.")); |
| return -1; |
| } |
| |
| /* RFC 8446 4.2.10 |
| * |
| * In order to accept early data, the server MUST have accepted a PSK cipher |
| * suite and selected the first key offered in the client's "pre_shared_key" |
| * extension. In addition, it MUST verify that the following values are the |
| * same as those associated with the selected PSK: |
| * - The TLS version number |
| * - The selected cipher suite |
| * - The selected ALPN [RFC7301] protocol, if any |
| * |
| * NOTE: |
| * - The TLS version number is checked in |
| * ssl_tls13_offered_psks_check_identity_match_ticket(). |
| * - ALPN is not checked for the time being (TODO). |
| */ |
| |
| if (handshake->selected_identity != 0) { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, ("EarlyData: rejected, the selected key in " |
| "`pre_shared_key` is not the first one.")); |
| return -1; |
| } |
| |
| if (handshake->ciphersuite_info->id != |
| ssl->session_negotiate->ciphersuite) { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, ("EarlyData: rejected, the selected ciphersuite is not the one " |
| "of the selected pre-shared key.")); |
| return -1; |
| |
| } |
| |
| if (!mbedtls_ssl_tls13_session_ticket_allow_early_data(ssl->session_negotiate)) { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, |
| ("EarlyData: rejected, early_data not allowed in ticket " |
| "permission bits.")); |
| return -1; |
| } |
| |
| return 0; |
| } |
| #endif /* MBEDTLS_SSL_EARLY_DATA */ |
| |
| /* Update the handshake state machine */ |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_postprocess_client_hello(mbedtls_ssl_context *ssl, |
| int hrr_required) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| /* |
| * Server certificate selection |
| */ |
| if (ssl->conf->f_cert_cb && (ret = ssl->conf->f_cert_cb(ssl)) != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "f_cert_cb", ret); |
| return ret; |
| } |
| #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) |
| ssl->handshake->sni_name = NULL; |
| ssl->handshake->sni_name_len = 0; |
| #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ |
| |
| ret = mbedtls_ssl_tls13_key_schedule_stage_early(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, |
| "mbedtls_ssl_tls1_3_key_schedule_stage_early", ret); |
| return ret; |
| } |
| |
| #if defined(MBEDTLS_SSL_EARLY_DATA) |
| if (ssl->handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(EARLY_DATA)) { |
| ssl->handshake->early_data_accepted = |
| (!hrr_required) && (ssl_tls13_check_early_data_requirements(ssl) == 0); |
| |
| if (ssl->handshake->early_data_accepted) { |
| ret = mbedtls_ssl_tls13_compute_early_transform(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "mbedtls_ssl_tls13_compute_early_transform", ret); |
| return ret; |
| } |
| } else { |
| ssl->discard_early_data_record = |
| hrr_required ? |
| MBEDTLS_SSL_EARLY_DATA_DISCARD : |
| MBEDTLS_SSL_EARLY_DATA_TRY_TO_DEPROTECT_AND_DISCARD; |
| } |
| } |
| #else |
| ((void) hrr_required); |
| #endif /* MBEDTLS_SSL_EARLY_DATA */ |
| |
| return 0; |
| } |
| |
| /* |
| * Main entry point from the state machine; orchestrates the otherfunctions. |
| */ |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_process_client_hello(mbedtls_ssl_context *ssl) |
| { |
| |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *buf = NULL; |
| size_t buflen = 0; |
| int parse_client_hello_ret; |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse client hello")); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_tls13_fetch_handshake_msg( |
| ssl, MBEDTLS_SSL_HS_CLIENT_HELLO, |
| &buf, &buflen)); |
| |
| MBEDTLS_SSL_PROC_CHK_NEG(ssl_tls13_parse_client_hello(ssl, buf, |
| buf + buflen)); |
| parse_client_hello_ret = ret; /* Store positive return value of |
| * parse_client_hello, |
| * as negative error codes are handled |
| * by MBEDTLS_SSL_PROC_CHK_NEG. */ |
| |
| /* |
| * Version 1.2 of the protocol has to be used for the handshake. |
| * If TLS 1.2 is not supported, abort the handshake. Otherwise, set the |
| * ssl->keep_current_message flag for the ClientHello to be kept and parsed |
| * as a TLS 1.2 ClientHello. We also change ssl->tls_version to |
| * MBEDTLS_SSL_VERSION_TLS1_2 thus from now on mbedtls_ssl_handshake_step() |
| * will dispatch to the TLS 1.2 state machine. |
| */ |
| if (SSL_CLIENT_HELLO_TLS1_2 == parse_client_hello_ret) { |
| /* Check if server supports TLS 1.2 */ |
| if (!mbedtls_ssl_conf_is_tls12_enabled(ssl->conf)) { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, ("TLS 1.2 not supported.")); |
| MBEDTLS_SSL_PEND_FATAL_ALERT( |
| MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION, |
| MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION); |
| return MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION; |
| } |
| ssl->keep_current_message = 1; |
| ssl->tls_version = MBEDTLS_SSL_VERSION_TLS1_2; |
| return 0; |
| } |
| |
| MBEDTLS_SSL_PROC_CHK( |
| ssl_tls13_postprocess_client_hello(ssl, parse_client_hello_ret == |
| SSL_CLIENT_HELLO_HRR_REQUIRED)); |
| |
| if (SSL_CLIENT_HELLO_OK == parse_client_hello_ret) { |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_HELLO); |
| } else { |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HELLO_RETRY_REQUEST); |
| } |
| |
| cleanup: |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse client hello")); |
| return ret; |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_SERVER_HELLO |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_prepare_server_hello(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *server_randbytes = |
| ssl->handshake->randbytes + MBEDTLS_CLIENT_HELLO_RANDOM_LEN; |
| |
| if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, server_randbytes, |
| MBEDTLS_SERVER_HELLO_RANDOM_LEN)) != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "f_rng", ret); |
| return ret; |
| } |
| |
| MBEDTLS_SSL_DEBUG_BUF(3, "server hello, random bytes", server_randbytes, |
| MBEDTLS_SERVER_HELLO_RANDOM_LEN); |
| |
| #if defined(MBEDTLS_HAVE_TIME) |
| ssl->session_negotiate->start = mbedtls_time(NULL); |
| #endif /* MBEDTLS_HAVE_TIME */ |
| |
| return ret; |
| } |
| |
| /* |
| * ssl_tls13_write_server_hello_supported_versions_ext (): |
| * |
| * struct { |
| * ProtocolVersion selected_version; |
| * } SupportedVersions; |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_server_hello_supported_versions_ext( |
| mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len) |
| { |
| *out_len = 0; |
| |
| MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, write selected version")); |
| |
| /* Check if we have space to write the extension: |
| * - extension_type (2 bytes) |
| * - extension_data_length (2 bytes) |
| * - selected_version (2 bytes) |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(buf, end, 6); |
| |
| MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS, buf, 0); |
| |
| MBEDTLS_PUT_UINT16_BE(2, buf, 2); |
| |
| mbedtls_ssl_write_version(buf + 4, |
| ssl->conf->transport, |
| ssl->tls_version); |
| |
| MBEDTLS_SSL_DEBUG_MSG(3, ("supported version: [%04x]", |
| ssl->tls_version)); |
| |
| *out_len = 6; |
| |
| mbedtls_ssl_tls13_set_hs_sent_ext_mask( |
| ssl, MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS); |
| |
| return 0; |
| } |
| |
| |
| |
| /* Generate and export a single key share. For hybrid KEMs, this can |
| * be called multiple times with the different components of the hybrid. */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_generate_and_write_key_share(mbedtls_ssl_context *ssl, |
| uint16_t named_group, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| *out_len = 0; |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED) |
| if (mbedtls_ssl_tls13_named_group_is_ecdhe(named_group) || |
| mbedtls_ssl_tls13_named_group_is_ffdh(named_group)) { |
| ret = mbedtls_ssl_tls13_generate_and_write_xxdh_key_exchange( |
| ssl, named_group, buf, end, out_len); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "mbedtls_ssl_tls13_generate_and_write_xxdh_key_exchange", |
| ret); |
| return ret; |
| } |
| } else |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED */ |
| if (0 /* Other kinds of KEMs */) { |
| } else { |
| ((void) ssl); |
| ((void) named_group); |
| ((void) buf); |
| ((void) end); |
| ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * ssl_tls13_write_key_share_ext |
| * |
| * Structure of key_share extension in ServerHello: |
| * |
| * struct { |
| * NamedGroup group; |
| * opaque key_exchange<1..2^16-1>; |
| * } KeyShareEntry; |
| * struct { |
| * KeyShareEntry server_share; |
| * } KeyShareServerHello; |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_key_share_ext(mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *p = buf; |
| uint16_t group = ssl->handshake->offered_group_id; |
| unsigned char *server_share = buf + 4; |
| size_t key_exchange_length; |
| |
| *out_len = 0; |
| |
| MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding key share extension")); |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("server hello, write selected_group: %s (%04x)", |
| mbedtls_ssl_named_group_to_str(group), |
| group)); |
| |
| /* Check if we have space for header and length fields: |
| * - extension_type (2 bytes) |
| * - extension_data_length (2 bytes) |
| * - group (2 bytes) |
| * - key_exchange_length (2 bytes) |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 8); |
| MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_KEY_SHARE, p, 0); |
| MBEDTLS_PUT_UINT16_BE(group, server_share, 0); |
| p += 8; |
| |
| /* When we introduce PQC-ECDHE hybrids, we'll want to call this |
| * function multiple times. */ |
| ret = ssl_tls13_generate_and_write_key_share( |
| ssl, group, server_share + 4, end, &key_exchange_length); |
| if (ret != 0) { |
| return ret; |
| } |
| p += key_exchange_length; |
| |
| MBEDTLS_PUT_UINT16_BE(key_exchange_length, server_share + 2, 0); |
| |
| MBEDTLS_PUT_UINT16_BE(p - server_share, buf, 2); |
| |
| *out_len = p - buf; |
| |
| mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_KEY_SHARE); |
| |
| return 0; |
| } |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_hrr_key_share_ext(mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len) |
| { |
| uint16_t selected_group = ssl->handshake->hrr_selected_group; |
| /* key_share Extension |
| * |
| * struct { |
| * select (Handshake.msg_type) { |
| * ... |
| * case hello_retry_request: |
| * NamedGroup selected_group; |
| * ... |
| * }; |
| * } KeyShare; |
| */ |
| |
| *out_len = 0; |
| |
| /* |
| * For a pure PSK key exchange, there is no group to agree upon. The purpose |
| * of the HRR is then to transmit a cookie to force the client to demonstrate |
| * reachability at their apparent network address (primarily useful for DTLS). |
| */ |
| if (!mbedtls_ssl_tls13_key_exchange_mode_with_ephemeral(ssl)) { |
| return 0; |
| } |
| |
| /* We should only send the key_share extension if the client's initial |
| * key share was not acceptable. */ |
| if (ssl->handshake->offered_group_id != 0) { |
| MBEDTLS_SSL_DEBUG_MSG(4, ("Skip key_share extension in HRR")); |
| return 0; |
| } |
| |
| if (selected_group == 0) { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("no matching named group found")); |
| return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; |
| } |
| |
| /* Check if we have enough space: |
| * - extension_type (2 bytes) |
| * - extension_data_length (2 bytes) |
| * - selected_group (2 bytes) |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(buf, end, 6); |
| |
| MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_KEY_SHARE, buf, 0); |
| MBEDTLS_PUT_UINT16_BE(2, buf, 2); |
| MBEDTLS_PUT_UINT16_BE(selected_group, buf, 4); |
| |
| MBEDTLS_SSL_DEBUG_MSG(3, |
| ("HRR selected_group: %s (%x)", |
| mbedtls_ssl_named_group_to_str(selected_group), |
| selected_group)); |
| |
| *out_len = 6; |
| |
| mbedtls_ssl_tls13_set_hs_sent_ext_mask(ssl, MBEDTLS_TLS_EXT_KEY_SHARE); |
| |
| return 0; |
| } |
| |
| /* |
| * Structure of ServerHello message: |
| * |
| * struct { |
| * ProtocolVersion legacy_version = 0x0303; // TLS v1.2 |
| * Random random; |
| * opaque legacy_session_id_echo<0..32>; |
| * CipherSuite cipher_suite; |
| * uint8 legacy_compression_method = 0; |
| * Extension extensions<6..2^16-1>; |
| * } ServerHello; |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_server_hello_body(mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len, |
| int is_hrr) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *p = buf; |
| unsigned char *p_extensions_len; |
| size_t output_len; |
| |
| *out_len = 0; |
| ssl->handshake->sent_extensions = MBEDTLS_SSL_EXT_MASK_NONE; |
| |
| /* ... |
| * ProtocolVersion legacy_version = 0x0303; // TLS 1.2 |
| * ... |
| * with ProtocolVersion defined as: |
| * uint16 ProtocolVersion; |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); |
| MBEDTLS_PUT_UINT16_BE(0x0303, p, 0); |
| p += 2; |
| |
| /* ... |
| * Random random; |
| * ... |
| * with Random defined as: |
| * opaque Random[MBEDTLS_SERVER_HELLO_RANDOM_LEN]; |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, MBEDTLS_SERVER_HELLO_RANDOM_LEN); |
| if (is_hrr) { |
| memcpy(p, mbedtls_ssl_tls13_hello_retry_request_magic, |
| MBEDTLS_SERVER_HELLO_RANDOM_LEN); |
| } else { |
| memcpy(p, &ssl->handshake->randbytes[MBEDTLS_CLIENT_HELLO_RANDOM_LEN], |
| MBEDTLS_SERVER_HELLO_RANDOM_LEN); |
| } |
| MBEDTLS_SSL_DEBUG_BUF(3, "server hello, random bytes", |
| p, MBEDTLS_SERVER_HELLO_RANDOM_LEN); |
| p += MBEDTLS_SERVER_HELLO_RANDOM_LEN; |
| |
| /* ... |
| * opaque legacy_session_id_echo<0..32>; |
| * ... |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 1 + ssl->session_negotiate->id_len); |
| *p++ = (unsigned char) ssl->session_negotiate->id_len; |
| if (ssl->session_negotiate->id_len > 0) { |
| memcpy(p, &ssl->session_negotiate->id[0], |
| ssl->session_negotiate->id_len); |
| p += ssl->session_negotiate->id_len; |
| |
| MBEDTLS_SSL_DEBUG_BUF(3, "session id", ssl->session_negotiate->id, |
| ssl->session_negotiate->id_len); |
| } |
| |
| /* ... |
| * CipherSuite cipher_suite; |
| * ... |
| * with CipherSuite defined as: |
| * uint8 CipherSuite[2]; |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); |
| MBEDTLS_PUT_UINT16_BE(ssl->session_negotiate->ciphersuite, p, 0); |
| p += 2; |
| MBEDTLS_SSL_DEBUG_MSG(3, |
| ("server hello, chosen ciphersuite: %s ( id=%d )", |
| mbedtls_ssl_get_ciphersuite_name( |
| ssl->session_negotiate->ciphersuite), |
| ssl->session_negotiate->ciphersuite)); |
| |
| /* ... |
| * uint8 legacy_compression_method = 0; |
| * ... |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 1); |
| *p++ = MBEDTLS_SSL_COMPRESS_NULL; |
| |
| /* ... |
| * Extension extensions<6..2^16-1>; |
| * ... |
| * struct { |
| * ExtensionType extension_type; (2 bytes) |
| * opaque extension_data<0..2^16-1>; |
| * } Extension; |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); |
| p_extensions_len = p; |
| p += 2; |
| |
| if ((ret = ssl_tls13_write_server_hello_supported_versions_ext( |
| ssl, p, end, &output_len)) != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "ssl_tls13_write_server_hello_supported_versions_ext", ret); |
| return ret; |
| } |
| p += output_len; |
| |
| if (mbedtls_ssl_tls13_key_exchange_mode_with_ephemeral(ssl)) { |
| if (is_hrr) { |
| ret = ssl_tls13_write_hrr_key_share_ext(ssl, p, end, &output_len); |
| } else { |
| ret = ssl_tls13_write_key_share_ext(ssl, p, end, &output_len); |
| } |
| if (ret != 0) { |
| return ret; |
| } |
| p += output_len; |
| } |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| if (!is_hrr && mbedtls_ssl_tls13_key_exchange_mode_with_psk(ssl)) { |
| ret = ssl_tls13_write_server_pre_shared_key_ext(ssl, p, end, &output_len); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "ssl_tls13_write_server_pre_shared_key_ext", |
| ret); |
| return ret; |
| } |
| p += output_len; |
| } |
| #endif |
| |
| MBEDTLS_PUT_UINT16_BE(p - p_extensions_len - 2, p_extensions_len, 0); |
| |
| MBEDTLS_SSL_DEBUG_BUF(4, "server hello extensions", |
| p_extensions_len, p - p_extensions_len); |
| |
| *out_len = p - buf; |
| |
| MBEDTLS_SSL_DEBUG_BUF(3, "server hello", buf, *out_len); |
| |
| MBEDTLS_SSL_PRINT_EXTS( |
| 3, is_hrr ? MBEDTLS_SSL_TLS1_3_HS_HELLO_RETRY_REQUEST : |
| MBEDTLS_SSL_HS_SERVER_HELLO, |
| ssl->handshake->sent_extensions); |
| |
| return ret; |
| } |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_finalize_server_hello(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| ret = mbedtls_ssl_tls13_compute_handshake_transform(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, |
| "mbedtls_ssl_tls13_compute_handshake_transform", |
| ret); |
| return ret; |
| } |
| |
| return ret; |
| } |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_server_hello(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *buf; |
| size_t buf_len, msg_len; |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("=> write server hello")); |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_prepare_server_hello(ssl)); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( |
| ssl, MBEDTLS_SSL_HS_SERVER_HELLO, &buf, &buf_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_server_hello_body(ssl, buf, |
| buf + buf_len, |
| &msg_len, |
| 0)); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( |
| ssl, MBEDTLS_SSL_HS_SERVER_HELLO, buf, msg_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg( |
| ssl, buf_len, msg_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_finalize_server_hello(ssl)); |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE) |
| /* The server sends a dummy change_cipher_spec record immediately |
| * after its first handshake message. This may either be after |
| * a ServerHello or a HelloRetryRequest. |
| */ |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_SERVER_CCS_AFTER_SERVER_HELLO); |
| #else |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS); |
| #endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */ |
| |
| cleanup: |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server hello")); |
| return ret; |
| } |
| |
| |
| /* |
| * Handler for MBEDTLS_SSL_HELLO_RETRY_REQUEST |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_prepare_hello_retry_request(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| if (ssl->handshake->hello_retry_request_flag) { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("Too many HRRs")); |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); |
| return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; |
| } |
| |
| /* |
| * Create stateless transcript hash for HRR |
| */ |
| MBEDTLS_SSL_DEBUG_MSG(4, ("Reset transcript for HRR")); |
| ret = mbedtls_ssl_reset_transcript_for_hrr(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_reset_transcript_for_hrr", ret); |
| return ret; |
| } |
| mbedtls_ssl_session_reset_msg_layer(ssl, 0); |
| |
| return 0; |
| } |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_hello_retry_request(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *buf; |
| size_t buf_len, msg_len; |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("=> write hello retry request")); |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_prepare_hello_retry_request(ssl)); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( |
| ssl, MBEDTLS_SSL_HS_SERVER_HELLO, |
| &buf, &buf_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_server_hello_body(ssl, buf, |
| buf + buf_len, |
| &msg_len, |
| 1)); |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( |
| ssl, MBEDTLS_SSL_HS_SERVER_HELLO, buf, msg_len)); |
| |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg(ssl, buf_len, |
| msg_len)); |
| |
| ssl->handshake->hello_retry_request_flag = 1; |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE) |
| /* The server sends a dummy change_cipher_spec record immediately |
| * after its first handshake message. This may either be after |
| * a ServerHello or a HelloRetryRequest. |
| */ |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_SERVER_CCS_AFTER_HELLO_RETRY_REQUEST); |
| #else |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_HELLO); |
| #endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */ |
| |
| cleanup: |
| MBEDTLS_SSL_DEBUG_MSG(2, ("<= write hello retry request")); |
| return ret; |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_ENCRYPTED_EXTENSIONS |
| */ |
| |
| /* |
| * struct { |
| * Extension extensions<0..2 ^ 16 - 1>; |
| * } EncryptedExtensions; |
| * |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_encrypted_extensions_body(mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *p = buf; |
| size_t extensions_len = 0; |
| unsigned char *p_extensions_len; |
| size_t output_len; |
| |
| *out_len = 0; |
| |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); |
| p_extensions_len = p; |
| p += 2; |
| |
| ((void) ssl); |
| ((void) ret); |
| ((void) output_len); |
| |
| #if defined(MBEDTLS_SSL_ALPN) |
| ret = mbedtls_ssl_write_alpn_ext(ssl, p, end, &output_len); |
| if (ret != 0) { |
| return ret; |
| } |
| p += output_len; |
| #endif /* MBEDTLS_SSL_ALPN */ |
| |
| #if defined(MBEDTLS_SSL_EARLY_DATA) |
| if (ssl->handshake->early_data_accepted) { |
| ret = mbedtls_ssl_tls13_write_early_data_ext( |
| ssl, 0, p, end, &output_len); |
| if (ret != 0) { |
| return ret; |
| } |
| p += output_len; |
| } |
| #endif /* MBEDTLS_SSL_EARLY_DATA */ |
| |
| #if defined(MBEDTLS_SSL_RECORD_SIZE_LIMIT) |
| if (ssl->handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(RECORD_SIZE_LIMIT)) { |
| ret = mbedtls_ssl_tls13_write_record_size_limit_ext( |
| ssl, p, end, &output_len); |
| if (ret != 0) { |
| return ret; |
| } |
| p += output_len; |
| } |
| #endif |
| |
| extensions_len = (p - p_extensions_len) - 2; |
| MBEDTLS_PUT_UINT16_BE(extensions_len, p_extensions_len, 0); |
| |
| *out_len = p - buf; |
| |
| MBEDTLS_SSL_DEBUG_BUF(4, "encrypted extensions", buf, *out_len); |
| |
| MBEDTLS_SSL_PRINT_EXTS( |
| 3, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, ssl->handshake->sent_extensions); |
| |
| return 0; |
| } |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_encrypted_extensions(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *buf; |
| size_t buf_len, msg_len; |
| |
| mbedtls_ssl_set_outbound_transform(ssl, |
| ssl->handshake->transform_handshake); |
| MBEDTLS_SSL_DEBUG_MSG( |
| 3, ("switching to handshake transform for outbound data")); |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("=> write encrypted extensions")); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( |
| ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, |
| &buf, &buf_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_encrypted_extensions_body( |
| ssl, buf, buf + buf_len, &msg_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( |
| ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, |
| buf, msg_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg( |
| ssl, buf_len, msg_len)); |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) |
| if (mbedtls_ssl_tls13_key_exchange_mode_with_psk(ssl)) { |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_FINISHED); |
| } else { |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CERTIFICATE_REQUEST); |
| } |
| #else |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_FINISHED); |
| #endif |
| |
| cleanup: |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("<= write encrypted extensions")); |
| return ret; |
| } |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) |
| #define SSL_CERTIFICATE_REQUEST_SEND_REQUEST 0 |
| #define SSL_CERTIFICATE_REQUEST_SKIP 1 |
| /* Coordination: |
| * Check whether a CertificateRequest message should be written. |
| * Returns a negative code on failure, or |
| * - SSL_CERTIFICATE_REQUEST_SEND_REQUEST |
| * - SSL_CERTIFICATE_REQUEST_SKIP |
| * indicating if the writing of the CertificateRequest |
| * should be skipped or not. |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_certificate_request_coordinate(mbedtls_ssl_context *ssl) |
| { |
| int authmode; |
| |
| #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) |
| if (ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET) { |
| authmode = ssl->handshake->sni_authmode; |
| } else |
| #endif |
| authmode = ssl->conf->authmode; |
| |
| if (authmode == MBEDTLS_SSL_VERIFY_NONE) { |
| ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_SKIP_VERIFY; |
| return SSL_CERTIFICATE_REQUEST_SKIP; |
| } |
| |
| ssl->handshake->certificate_request_sent = 1; |
| |
| return SSL_CERTIFICATE_REQUEST_SEND_REQUEST; |
| } |
| |
| /* |
| * struct { |
| * opaque certificate_request_context<0..2^8-1>; |
| * Extension extensions<2..2^16-1>; |
| * } CertificateRequest; |
| * |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_certificate_request_body(mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| const unsigned char *end, |
| size_t *out_len) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *p = buf; |
| size_t output_len = 0; |
| unsigned char *p_extensions_len; |
| |
| *out_len = 0; |
| |
| /* Check if we have enough space: |
| * - certificate_request_context (1 byte) |
| * - extensions length (2 bytes) |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 3); |
| |
| /* |
| * Write certificate_request_context |
| */ |
| /* |
| * We use a zero length context for the normal handshake |
| * messages. For post-authentication handshake messages |
| * this request context would be set to a non-zero value. |
| */ |
| *p++ = 0x0; |
| |
| /* |
| * Write extensions |
| */ |
| /* The extensions must contain the signature_algorithms. */ |
| p_extensions_len = p; |
| p += 2; |
| ret = mbedtls_ssl_write_sig_alg_ext(ssl, p, end, &output_len); |
| if (ret != 0) { |
| return ret; |
| } |
| |
| p += output_len; |
| MBEDTLS_PUT_UINT16_BE(p - p_extensions_len - 2, p_extensions_len, 0); |
| |
| *out_len = p - buf; |
| |
| MBEDTLS_SSL_PRINT_EXTS( |
| 3, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, ssl->handshake->sent_extensions); |
| |
| return 0; |
| } |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_certificate_request(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate request")); |
| |
| MBEDTLS_SSL_PROC_CHK_NEG(ssl_tls13_certificate_request_coordinate(ssl)); |
| |
| if (ret == SSL_CERTIFICATE_REQUEST_SEND_REQUEST) { |
| unsigned char *buf; |
| size_t buf_len, msg_len; |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( |
| ssl, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, |
| &buf, &buf_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_certificate_request_body( |
| ssl, buf, buf + buf_len, &msg_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( |
| ssl, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, |
| buf, msg_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg( |
| ssl, buf_len, msg_len)); |
| } else if (ret == SSL_CERTIFICATE_REQUEST_SKIP) { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip write certificate request")); |
| ret = 0; |
| } else { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); |
| ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| goto cleanup; |
| } |
| |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_CERTIFICATE); |
| cleanup: |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("<= write certificate request")); |
| return ret; |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_SERVER_CERTIFICATE |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_server_certificate(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| #if defined(MBEDTLS_X509_CRT_PARSE_C) |
| if ((ssl_tls13_pick_key_cert(ssl) != 0) || |
| mbedtls_ssl_own_cert(ssl) == NULL) { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("No certificate available.")); |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); |
| return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE; |
| } |
| #endif /* MBEDTLS_X509_CRT_PARSE_C */ |
| |
| ret = mbedtls_ssl_tls13_write_certificate(ssl); |
| if (ret != 0) { |
| return ret; |
| } |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CERTIFICATE_VERIFY); |
| return 0; |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_CERTIFICATE_VERIFY |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_certificate_verify(mbedtls_ssl_context *ssl) |
| { |
| int ret = mbedtls_ssl_tls13_write_certificate_verify(ssl); |
| if (ret != 0) { |
| return ret; |
| } |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_SERVER_FINISHED); |
| return 0; |
| } |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ |
| |
| /* |
| * RFC 8446 section A.2 |
| * |
| * | Send ServerHello |
| * | K_send = handshake |
| * | Send EncryptedExtensions |
| * | [Send CertificateRequest] |
| * Can send | [Send Certificate + CertificateVerify] |
| * app data | Send Finished |
| * after --> | K_send = application |
| * here +--------+--------+ |
| * No 0-RTT | | 0-RTT |
| * | | |
| * K_recv = handshake | | K_recv = early data |
| * [Skip decrypt errors] | +------> WAIT_EOED -+ |
| * | | Recv | | Recv EndOfEarlyData |
| * | | early data | | K_recv = handshake |
| * | +------------+ | |
| * | | |
| * +> WAIT_FLIGHT2 <--------+ |
| * | |
| * +--------+--------+ |
| * No auth | | Client auth |
| * | | |
| * | v |
| * | WAIT_CERT |
| * | Recv | | Recv Certificate |
| * | empty | v |
| * | Certificate | WAIT_CV |
| * | | | Recv |
| * | v | CertificateVerify |
| * +-> WAIT_FINISHED <---+ |
| * | Recv Finished |
| * |
| * |
| * The following function handles the state changes after WAIT_FLIGHT2 in the |
| * above diagram. We are not going to receive early data related messages |
| * anymore, prepare to receive the first handshake message of the client |
| * second flight. |
| */ |
| static void ssl_tls13_prepare_for_handshake_second_flight( |
| mbedtls_ssl_context *ssl) |
| { |
| if (ssl->handshake->certificate_request_sent) { |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_CERTIFICATE); |
| } else { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("skip parse certificate")); |
| MBEDTLS_SSL_DEBUG_MSG(2, ("skip parse certificate verify")); |
| |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_FINISHED); |
| } |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_SERVER_FINISHED |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_server_finished(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| ret = mbedtls_ssl_tls13_write_finished_message(ssl); |
| if (ret != 0) { |
| return ret; |
| } |
| |
| ret = mbedtls_ssl_tls13_compute_application_transform(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_PEND_FATAL_ALERT( |
| MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE, |
| MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE); |
| return ret; |
| } |
| |
| #if defined(MBEDTLS_SSL_EARLY_DATA) |
| if (ssl->handshake->early_data_accepted) { |
| /* See RFC 8446 section A.2 for more information */ |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, ("Switch to early keys for inbound traffic. " |
| "( K_recv = early data )")); |
| mbedtls_ssl_set_inbound_transform( |
| ssl, ssl->handshake->transform_earlydata); |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_END_OF_EARLY_DATA); |
| return 0; |
| } |
| #endif /* MBEDTLS_SSL_EARLY_DATA */ |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, ("Switch to handshake keys for inbound traffic " |
| "( K_recv = handshake )")); |
| mbedtls_ssl_set_inbound_transform(ssl, ssl->handshake->transform_handshake); |
| |
| ssl_tls13_prepare_for_handshake_second_flight(ssl); |
| |
| return 0; |
| } |
| |
| #if defined(MBEDTLS_SSL_EARLY_DATA) |
| /* |
| * Handler for MBEDTLS_SSL_END_OF_EARLY_DATA |
| */ |
| #define SSL_GOT_END_OF_EARLY_DATA 0 |
| #define SSL_GOT_EARLY_DATA 1 |
| /* Coordination: |
| * Deals with the ambiguity of not knowing if the next message is an |
| * EndOfEarlyData message or an application message containing early data. |
| * Returns a negative code on failure, or |
| * - SSL_GOT_END_OF_EARLY_DATA |
| * - SSL_GOT_EARLY_DATA |
| * indicating which message is received. |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_end_of_early_data_coordinate(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| if ((ret = mbedtls_ssl_read_record(ssl, 0)) != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_read_record", ret); |
| return ret; |
| } |
| ssl->keep_current_message = 1; |
| |
| if (ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && |
| ssl->in_msg[0] == MBEDTLS_SSL_HS_END_OF_EARLY_DATA) { |
| MBEDTLS_SSL_DEBUG_MSG(3, ("Received an end_of_early_data message.")); |
| return SSL_GOT_END_OF_EARLY_DATA; |
| } |
| |
| if (ssl->in_msgtype == MBEDTLS_SSL_MSG_APPLICATION_DATA) { |
| if (ssl->in_offt == NULL) { |
| MBEDTLS_SSL_DEBUG_MSG(3, ("Received early data")); |
| /* Set the reading pointer */ |
| ssl->in_offt = ssl->in_msg; |
| ret = mbedtls_ssl_tls13_check_early_data_len(ssl, ssl->in_msglen); |
| if (ret != 0) { |
| return ret; |
| } |
| } |
| return SSL_GOT_EARLY_DATA; |
| } |
| |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE, |
| MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE); |
| return MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE; |
| } |
| |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_parse_end_of_early_data(mbedtls_ssl_context *ssl, |
| const unsigned char *buf, |
| const unsigned char *end) |
| { |
| /* RFC 8446 section 4.5 |
| * |
| * struct {} EndOfEarlyData; |
| */ |
| if (buf != end) { |
| MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, |
| MBEDTLS_ERR_SSL_DECODE_ERROR); |
| return MBEDTLS_ERR_SSL_DECODE_ERROR; |
| } |
| return 0; |
| } |
| |
| /* |
| * RFC 8446 section A.2 |
| * |
| * | Send ServerHello |
| * | K_send = handshake |
| * | Send EncryptedExtensions |
| * | [Send CertificateRequest] |
| * Can send | [Send Certificate + CertificateVerify] |
| * app data | Send Finished |
| * after --> | K_send = application |
| * here +--------+--------+ |
| * No 0-RTT | | 0-RTT |
| * | | |
| * K_recv = handshake | | K_recv = early data |
| * [Skip decrypt errors] | +------> WAIT_EOED -+ |
| * | | Recv | | Recv EndOfEarlyData |
| * | | early data | | K_recv = handshake |
| * | +------------+ | |
| * | | |
| * +> WAIT_FLIGHT2 <--------+ |
| * | |
| * +--------+--------+ |
| * No auth | | Client auth |
| * | | |
| * | v |
| * | WAIT_CERT |
| * | Recv | | Recv Certificate |
| * | empty | v |
| * | Certificate | WAIT_CV |
| * | | | Recv |
| * | v | CertificateVerify |
| * +-> WAIT_FINISHED <---+ |
| * | Recv Finished |
| * |
| * The function handles actions and state changes from 0-RTT to WAIT_FLIGHT2 in |
| * the above diagram. |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_process_end_of_early_data(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("=> ssl_tls13_process_end_of_early_data")); |
| |
| MBEDTLS_SSL_PROC_CHK_NEG(ssl_tls13_end_of_early_data_coordinate(ssl)); |
| |
| if (ret == SSL_GOT_END_OF_EARLY_DATA) { |
| unsigned char *buf; |
| size_t buf_len; |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_tls13_fetch_handshake_msg( |
| ssl, MBEDTLS_SSL_HS_END_OF_EARLY_DATA, |
| &buf, &buf_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_parse_end_of_early_data( |
| ssl, buf, buf + buf_len)); |
| |
| MBEDTLS_SSL_DEBUG_MSG( |
| 1, ("Switch to handshake keys for inbound traffic" |
| "( K_recv = handshake )")); |
| mbedtls_ssl_set_inbound_transform( |
| ssl, ssl->handshake->transform_handshake); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum( |
| ssl, MBEDTLS_SSL_HS_END_OF_EARLY_DATA, |
| buf, buf_len)); |
| |
| ssl_tls13_prepare_for_handshake_second_flight(ssl); |
| |
| } else if (ret == SSL_GOT_EARLY_DATA) { |
| ret = MBEDTLS_ERR_SSL_RECEIVED_EARLY_DATA; |
| goto cleanup; |
| } else { |
| MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); |
| ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| goto cleanup; |
| } |
| |
| cleanup: |
| MBEDTLS_SSL_DEBUG_MSG(2, ("<= ssl_tls13_process_end_of_early_data")); |
| return ret; |
| } |
| #endif /* MBEDTLS_SSL_EARLY_DATA */ |
| |
| /* |
| * Handler for MBEDTLS_SSL_CLIENT_FINISHED |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_process_client_finished(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| ret = mbedtls_ssl_tls13_process_finished_message(ssl); |
| if (ret != 0) { |
| return ret; |
| } |
| |
| ret = mbedtls_ssl_tls13_compute_resumption_master_secret(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "mbedtls_ssl_tls13_compute_resumption_master_secret", ret); |
| } |
| |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HANDSHAKE_WRAPUP); |
| return 0; |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_HANDSHAKE_WRAPUP |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_handshake_wrapup(mbedtls_ssl_context *ssl) |
| { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("handshake: done")); |
| |
| mbedtls_ssl_tls13_handshake_wrapup(ssl); |
| |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) && \ |
| defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| /* TODO: Remove the check of SOME_PSK_ENABLED since SESSION_TICKETS requires |
| * SOME_PSK_ENABLED to be enabled. Here is just to make CI happy. It is |
| * expected to be resolved with issue#6395. |
| */ |
| /* Sent NewSessionTicket message only when client supports PSK */ |
| if (mbedtls_ssl_tls13_is_some_psk_supported(ssl)) { |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET); |
| } else |
| #endif |
| { |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HANDSHAKE_OVER); |
| } |
| return 0; |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET |
| */ |
| #define SSL_NEW_SESSION_TICKET_SKIP 0 |
| #define SSL_NEW_SESSION_TICKET_WRITE 1 |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_new_session_ticket_coordinate(mbedtls_ssl_context *ssl) |
| { |
| /* Check whether the use of session tickets is enabled */ |
| if (ssl->conf->f_ticket_write == NULL) { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("NewSessionTicket: disabled," |
| " callback is not set")); |
| return SSL_NEW_SESSION_TICKET_SKIP; |
| } |
| if (ssl->conf->new_session_tickets_count == 0) { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("NewSessionTicket: disabled," |
| " configured count is zero")); |
| return SSL_NEW_SESSION_TICKET_SKIP; |
| } |
| |
| if (ssl->handshake->new_session_tickets_count == 0) { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("NewSessionTicket: all tickets have " |
| "been sent.")); |
| return SSL_NEW_SESSION_TICKET_SKIP; |
| } |
| |
| return SSL_NEW_SESSION_TICKET_WRITE; |
| } |
| |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_prepare_new_session_ticket(mbedtls_ssl_context *ssl, |
| unsigned char *ticket_nonce, |
| size_t ticket_nonce_size) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_ssl_session *session = ssl->session; |
| mbedtls_ssl_ciphersuite_t *ciphersuite_info; |
| psa_algorithm_t psa_hash_alg; |
| int hash_length; |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("=> prepare NewSessionTicket msg")); |
| |
| /* Set ticket_flags depends on the advertised psk key exchange mode */ |
| mbedtls_ssl_tls13_session_clear_ticket_flags( |
| session, MBEDTLS_SSL_TLS1_3_TICKET_FLAGS_MASK); |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED) |
| mbedtls_ssl_tls13_session_set_ticket_flags( |
| session, ssl->handshake->tls13_kex_modes); |
| #endif |
| |
| #if defined(MBEDTLS_SSL_EARLY_DATA) |
| if (ssl->conf->early_data_enabled == MBEDTLS_SSL_EARLY_DATA_ENABLED && |
| ssl->conf->max_early_data_size > 0) { |
| mbedtls_ssl_tls13_session_set_ticket_flags( |
| session, MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_EARLY_DATA); |
| session->max_early_data_size = ssl->conf->max_early_data_size; |
| } |
| #endif /* MBEDTLS_SSL_EARLY_DATA */ |
| |
| MBEDTLS_SSL_PRINT_TICKET_FLAGS(4, session->ticket_flags); |
| |
| /* Generate ticket_age_add */ |
| if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, |
| (unsigned char *) &session->ticket_age_add, |
| sizeof(session->ticket_age_add)) != 0)) { |
| MBEDTLS_SSL_DEBUG_RET(1, "generate_ticket_age_add", ret); |
| return ret; |
| } |
| MBEDTLS_SSL_DEBUG_MSG(3, ("ticket_age_add: %u", |
| (unsigned int) session->ticket_age_add)); |
| |
| /* Generate ticket_nonce */ |
| ret = ssl->conf->f_rng(ssl->conf->p_rng, ticket_nonce, ticket_nonce_size); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "generate_ticket_nonce", ret); |
| return ret; |
| } |
| MBEDTLS_SSL_DEBUG_BUF(3, "ticket_nonce:", |
| ticket_nonce, ticket_nonce_size); |
| |
| ciphersuite_info = |
| (mbedtls_ssl_ciphersuite_t *) ssl->handshake->ciphersuite_info; |
| psa_hash_alg = mbedtls_md_psa_alg_from_type((mbedtls_md_type_t) ciphersuite_info->mac); |
| hash_length = PSA_HASH_LENGTH(psa_hash_alg); |
| if (hash_length == -1 || |
| (size_t) hash_length > sizeof(session->resumption_key)) { |
| return MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| } |
| |
| /* In this code the psk key length equals the length of the hash */ |
| session->resumption_key_len = hash_length; |
| session->ciphersuite = ciphersuite_info->id; |
| |
| /* Compute resumption key |
| * |
| * HKDF-Expand-Label( resumption_master_secret, |
| * "resumption", ticket_nonce, Hash.length ) |
| */ |
| ret = mbedtls_ssl_tls13_hkdf_expand_label( |
| psa_hash_alg, |
| session->app_secrets.resumption_master_secret, |
| hash_length, |
| MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN(resumption), |
| ticket_nonce, |
| ticket_nonce_size, |
| session->resumption_key, |
| hash_length); |
| |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(2, |
| "Creating the ticket-resumed PSK failed", |
| ret); |
| return ret; |
| } |
| MBEDTLS_SSL_DEBUG_BUF(3, "Ticket-resumed PSK", |
| session->resumption_key, |
| session->resumption_key_len); |
| |
| MBEDTLS_SSL_DEBUG_BUF(3, "resumption_master_secret", |
| session->app_secrets.resumption_master_secret, |
| hash_length); |
| |
| return 0; |
| } |
| |
| /* This function creates a NewSessionTicket message in the following format: |
| * |
| * struct { |
| * uint32 ticket_lifetime; |
| * uint32 ticket_age_add; |
| * opaque ticket_nonce<0..255>; |
| * opaque ticket<1..2^16-1>; |
| * Extension extensions<0..2^16-2>; |
| * } NewSessionTicket; |
| * |
| * The ticket inside the NewSessionTicket message is an encrypted container |
| * carrying the necessary information so that the server is later able to |
| * re-start the communication. |
| * |
| * The following fields are placed inside the ticket by the |
| * f_ticket_write() function: |
| * |
| * - creation time (ticket_creation_time) |
| * - flags (ticket_flags) |
| * - age add (ticket_age_add) |
| * - key (resumption_key) |
| * - key length (resumption_key_len) |
| * - ciphersuite (ciphersuite) |
| * - max_early_data_size (max_early_data_size) |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_tls13_write_new_session_ticket_body(mbedtls_ssl_context *ssl, |
| unsigned char *buf, |
| unsigned char *end, |
| size_t *out_len, |
| unsigned char *ticket_nonce, |
| size_t ticket_nonce_size) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *p = buf; |
| mbedtls_ssl_session *session = ssl->session; |
| size_t ticket_len; |
| uint32_t ticket_lifetime; |
| unsigned char *p_extensions_len; |
| |
| *out_len = 0; |
| MBEDTLS_SSL_DEBUG_MSG(2, ("=> write NewSessionTicket msg")); |
| |
| /* |
| * ticket_lifetime 4 bytes |
| * ticket_age_add 4 bytes |
| * ticket_nonce 1 + ticket_nonce_size bytes |
| * ticket >=2 bytes |
| */ |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 4 + 4 + 1 + ticket_nonce_size + 2); |
| |
| /* Generate ticket and ticket_lifetime */ |
| #if defined(MBEDTLS_HAVE_TIME) |
| session->ticket_creation_time = mbedtls_ms_time(); |
| #endif |
| ret = ssl->conf->f_ticket_write(ssl->conf->p_ticket, |
| session, |
| p + 9 + ticket_nonce_size + 2, |
| end, |
| &ticket_len, |
| &ticket_lifetime); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "write_ticket", ret); |
| return ret; |
| } |
| /* RFC 8446 4.6.1 |
| * ticket_lifetime: Indicates the lifetime in seconds as a 32-bit |
| * unsigned integer in network byte order from the time of ticket |
| * issuance. Servers MUST NOT use any value greater than |
| * 604800 seconds (7 days). The value of zero indicates that the |
| * ticket should be discarded immediately. Clients MUST NOT cache |
| * tickets for longer than 7 days, regardless of the ticket_lifetime, |
| * and MAY delete tickets earlier based on local policy. A server |
| * MAY treat a ticket as valid for a shorter period of time than what |
| * is stated in the ticket_lifetime. |
| */ |
| if (ticket_lifetime > MBEDTLS_SSL_TLS1_3_MAX_ALLOWED_TICKET_LIFETIME) { |
| ticket_lifetime = MBEDTLS_SSL_TLS1_3_MAX_ALLOWED_TICKET_LIFETIME; |
| } |
| MBEDTLS_PUT_UINT32_BE(ticket_lifetime, p, 0); |
| MBEDTLS_SSL_DEBUG_MSG(3, ("ticket_lifetime: %u", |
| (unsigned int) ticket_lifetime)); |
| |
| /* Write ticket_age_add */ |
| MBEDTLS_PUT_UINT32_BE(session->ticket_age_add, p, 4); |
| MBEDTLS_SSL_DEBUG_MSG(3, ("ticket_age_add: %u", |
| (unsigned int) session->ticket_age_add)); |
| |
| /* Write ticket_nonce */ |
| p[8] = (unsigned char) ticket_nonce_size; |
| if (ticket_nonce_size > 0) { |
| memcpy(p + 9, ticket_nonce, ticket_nonce_size); |
| } |
| p += 9 + ticket_nonce_size; |
| |
| /* Write ticket */ |
| MBEDTLS_PUT_UINT16_BE(ticket_len, p, 0); |
| p += 2; |
| MBEDTLS_SSL_DEBUG_BUF(4, "ticket", p, ticket_len); |
| p += ticket_len; |
| |
| /* Ticket Extensions |
| * |
| * Extension extensions<0..2^16-2>; |
| */ |
| ssl->handshake->sent_extensions = MBEDTLS_SSL_EXT_MASK_NONE; |
| |
| MBEDTLS_SSL_CHK_BUF_PTR(p, end, 2); |
| p_extensions_len = p; |
| p += 2; |
| |
| #if defined(MBEDTLS_SSL_EARLY_DATA) |
| if (mbedtls_ssl_tls13_session_ticket_allow_early_data(session)) { |
| size_t output_len; |
| |
| if ((ret = mbedtls_ssl_tls13_write_early_data_ext( |
| ssl, 1, p, end, &output_len)) != 0) { |
| MBEDTLS_SSL_DEBUG_RET( |
| 1, "mbedtls_ssl_tls13_write_early_data_ext", ret); |
| return ret; |
| } |
| p += output_len; |
| } else { |
| MBEDTLS_SSL_DEBUG_MSG( |
| 4, ("early_data not allowed, " |
| "skip early_data extension in NewSessionTicket")); |
| } |
| |
| #endif /* MBEDTLS_SSL_EARLY_DATA */ |
| |
| MBEDTLS_PUT_UINT16_BE(p - p_extensions_len - 2, p_extensions_len, 0); |
| |
| *out_len = p - buf; |
| MBEDTLS_SSL_DEBUG_BUF(4, "ticket", buf, *out_len); |
| MBEDTLS_SSL_DEBUG_MSG(2, ("<= write new session ticket")); |
| |
| MBEDTLS_SSL_PRINT_EXTS( |
| 3, MBEDTLS_SSL_HS_NEW_SESSION_TICKET, ssl->handshake->sent_extensions); |
| |
| return 0; |
| } |
| |
| /* |
| * Handler for MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET |
| */ |
| static int ssl_tls13_write_new_session_ticket(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| MBEDTLS_SSL_PROC_CHK_NEG(ssl_tls13_write_new_session_ticket_coordinate(ssl)); |
| |
| if (ret == SSL_NEW_SESSION_TICKET_WRITE) { |
| unsigned char ticket_nonce[MBEDTLS_SSL_TLS1_3_TICKET_NONCE_LENGTH]; |
| unsigned char *buf; |
| size_t buf_len, msg_len; |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_prepare_new_session_ticket( |
| ssl, ticket_nonce, sizeof(ticket_nonce))); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg( |
| ssl, MBEDTLS_SSL_HS_NEW_SESSION_TICKET, |
| &buf, &buf_len)); |
| |
| MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_new_session_ticket_body( |
| ssl, buf, buf + buf_len, &msg_len, |
| ticket_nonce, sizeof(ticket_nonce))); |
| |
| MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg( |
| ssl, buf_len, msg_len)); |
| |
| /* Limit session tickets count to one when resumption connection. |
| * |
| * See document of mbedtls_ssl_conf_new_session_tickets. |
| */ |
| if (ssl->handshake->resume == 1) { |
| ssl->handshake->new_session_tickets_count = 0; |
| } else { |
| ssl->handshake->new_session_tickets_count--; |
| } |
| |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET_FLUSH); |
| } else { |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HANDSHAKE_OVER); |
| } |
| |
| cleanup: |
| |
| return ret; |
| } |
| #endif /* MBEDTLS_SSL_SESSION_TICKETS */ |
| |
| /* |
| * TLS 1.3 State Machine -- server side |
| */ |
| int mbedtls_ssl_tls13_handshake_server_step(mbedtls_ssl_context *ssl) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| if (ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL) { |
| return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG(2, ("tls13 server state: %s(%d)", |
| mbedtls_ssl_states_str((mbedtls_ssl_states) ssl->state), |
| ssl->state)); |
| |
| switch (ssl->state) { |
| /* start state */ |
| case MBEDTLS_SSL_HELLO_REQUEST: |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_HELLO); |
| ret = 0; |
| break; |
| |
| case MBEDTLS_SSL_CLIENT_HELLO: |
| ret = ssl_tls13_process_client_hello(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "ssl_tls13_process_client_hello", ret); |
| } |
| break; |
| |
| case MBEDTLS_SSL_HELLO_RETRY_REQUEST: |
| ret = ssl_tls13_write_hello_retry_request(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "ssl_tls13_write_hello_retry_request", ret); |
| return ret; |
| } |
| break; |
| |
| case MBEDTLS_SSL_SERVER_HELLO: |
| ret = ssl_tls13_write_server_hello(ssl); |
| break; |
| |
| case MBEDTLS_SSL_ENCRYPTED_EXTENSIONS: |
| ret = ssl_tls13_write_encrypted_extensions(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, "ssl_tls13_write_encrypted_extensions", ret); |
| return ret; |
| } |
| break; |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) |
| case MBEDTLS_SSL_CERTIFICATE_REQUEST: |
| ret = ssl_tls13_write_certificate_request(ssl); |
| break; |
| |
| case MBEDTLS_SSL_SERVER_CERTIFICATE: |
| ret = ssl_tls13_write_server_certificate(ssl); |
| break; |
| |
| case MBEDTLS_SSL_CERTIFICATE_VERIFY: |
| ret = ssl_tls13_write_certificate_verify(ssl); |
| break; |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ |
| |
| /* |
| * Injection of dummy-CCS's for middlebox compatibility |
| */ |
| #if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE) |
| case MBEDTLS_SSL_SERVER_CCS_AFTER_HELLO_RETRY_REQUEST: |
| ret = mbedtls_ssl_tls13_write_change_cipher_spec(ssl); |
| if (ret == 0) { |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_CLIENT_HELLO); |
| } |
| break; |
| |
| case MBEDTLS_SSL_SERVER_CCS_AFTER_SERVER_HELLO: |
| ret = mbedtls_ssl_tls13_write_change_cipher_spec(ssl); |
| if (ret != 0) { |
| break; |
| } |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS); |
| break; |
| #endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */ |
| |
| case MBEDTLS_SSL_SERVER_FINISHED: |
| ret = ssl_tls13_write_server_finished(ssl); |
| break; |
| |
| #if defined(MBEDTLS_SSL_EARLY_DATA) |
| case MBEDTLS_SSL_END_OF_EARLY_DATA: |
| ret = ssl_tls13_process_end_of_early_data(ssl); |
| break; |
| #endif /* MBEDTLS_SSL_EARLY_DATA */ |
| |
| case MBEDTLS_SSL_CLIENT_FINISHED: |
| ret = ssl_tls13_process_client_finished(ssl); |
| break; |
| |
| case MBEDTLS_SSL_HANDSHAKE_WRAPUP: |
| ret = ssl_tls13_handshake_wrapup(ssl); |
| break; |
| |
| #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) |
| case MBEDTLS_SSL_CLIENT_CERTIFICATE: |
| ret = mbedtls_ssl_tls13_process_certificate(ssl); |
| if (ret == 0) { |
| if (ssl->session_negotiate->peer_cert != NULL) { |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY); |
| } else { |
| MBEDTLS_SSL_DEBUG_MSG(2, ("skip parse certificate verify")); |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_CLIENT_FINISHED); |
| } |
| } |
| break; |
| |
| case MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY: |
| ret = mbedtls_ssl_tls13_process_certificate_verify(ssl); |
| if (ret == 0) { |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_CLIENT_FINISHED); |
| } |
| break; |
| #endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */ |
| |
| #if defined(MBEDTLS_SSL_SESSION_TICKETS) |
| case MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET: |
| ret = ssl_tls13_write_new_session_ticket(ssl); |
| if (ret != 0) { |
| MBEDTLS_SSL_DEBUG_RET(1, |
| "ssl_tls13_write_new_session_ticket ", |
| ret); |
| } |
| break; |
| case MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET_FLUSH: |
| /* This state is necessary to do the flush of the New Session |
| * Ticket message written in MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET |
| * as part of ssl_prepare_handshake_step. |
| */ |
| ret = 0; |
| |
| if (ssl->handshake->new_session_tickets_count == 0) { |
| mbedtls_ssl_handshake_set_state(ssl, MBEDTLS_SSL_HANDSHAKE_OVER); |
| } else { |
| mbedtls_ssl_handshake_set_state( |
| ssl, MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET); |
| } |
| break; |
| |
| #endif /* MBEDTLS_SSL_SESSION_TICKETS */ |
| |
| default: |
| MBEDTLS_SSL_DEBUG_MSG(1, ("invalid state %d", ssl->state)); |
| return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; |
| } |
| |
| return ret; |
| } |
| |
| #endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_PROTO_TLS1_3 */ |