/* * SSLv3/TLSv1 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) #include "mbedtls/platform.h" #include "mbedtls/ssl.h" #include "mbedtls/ssl_internal.h" #include "mbedtls/debug.h" #include "mbedtls/error.h" #include "mbedtls/platform_util.h" #include "constant_time_internal.h" #include "mbedtls/constant_time.h" #include #if defined(MBEDTLS_ECP_C) #include "mbedtls/ecp.h" #endif #if defined(MBEDTLS_HAVE_TIME) #include "mbedtls/platform_time.h" #endif #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) int mbedtls_ssl_set_client_transport_id(mbedtls_ssl_context *ssl, const unsigned char *info, size_t ilen) { if (ssl->conf->endpoint != MBEDTLS_SSL_IS_SERVER) { return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; } mbedtls_free(ssl->cli_id); if ((ssl->cli_id = mbedtls_calloc(1, ilen)) == NULL) { return MBEDTLS_ERR_SSL_ALLOC_FAILED; } memcpy(ssl->cli_id, info, ilen); ssl->cli_id_len = ilen; return 0; } void mbedtls_ssl_conf_dtls_cookies(mbedtls_ssl_config *conf, mbedtls_ssl_cookie_write_t *f_cookie_write, mbedtls_ssl_cookie_check_t *f_cookie_check, void *p_cookie) { conf->f_cookie_write = f_cookie_write; conf->f_cookie_check = f_cookie_check; conf->p_cookie = p_cookie; } #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */ #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_servername_ext(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t servername_list_size, hostname_len; const unsigned char *p; MBEDTLS_SSL_DEBUG_MSG(3, ("parse ServerName extension")); if (len < 2) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } servername_list_size = ((buf[0] << 8) | (buf[1])); if (servername_list_size + 2 != len) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } p = buf + 2; while (servername_list_size > 2) { hostname_len = ((p[1] << 8) | p[2]); if (hostname_len + 3 > servername_list_size) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } if (p[0] == MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME) { ret = ssl->conf->f_sni(ssl->conf->p_sni, ssl, p + 3, hostname_len); if (ret != 0) { MBEDTLS_SSL_DEBUG_RET(1, "ssl_sni_wrapper", ret); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_UNRECOGNIZED_NAME); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } return 0; } servername_list_size -= hostname_len + 3; p += hostname_len + 3; } if (servername_list_size != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } return 0; } #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_conf_has_psk_or_cb(mbedtls_ssl_config const *conf) { if (conf->f_psk != NULL) { return 1; } if (conf->psk_identity_len == 0 || conf->psk_identity == NULL) { return 0; } if (conf->psk != NULL && conf->psk_len != 0) { return 1; } #if defined(MBEDTLS_USE_PSA_CRYPTO) if (!mbedtls_svc_key_id_is_null(conf->psk_opaque)) { return 1; } #endif /* MBEDTLS_USE_PSA_CRYPTO */ return 0; } #if defined(MBEDTLS_USE_PSA_CRYPTO) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_use_opaque_psk(mbedtls_ssl_context const *ssl) { if (ssl->conf->f_psk != NULL) { /* If we've used a callback to select the PSK, * the static configuration is irrelevant. */ if (!mbedtls_svc_key_id_is_null(ssl->handshake->psk_opaque)) { return 1; } return 0; } if (!mbedtls_svc_key_id_is_null(ssl->conf->psk_opaque)) { return 1; } return 0; } #endif /* MBEDTLS_USE_PSA_CRYPTO */ #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_renegotiation_info(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) { /* Check verify-data in constant-time. The length OTOH is no secret */ if (len != 1 + ssl->verify_data_len || buf[0] != ssl->verify_data_len || mbedtls_ct_memcmp(buf + 1, ssl->peer_verify_data, ssl->verify_data_len) != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("non-matching renegotiation info")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } } else #endif /* MBEDTLS_SSL_RENEGOTIATION */ { if (len != 1 || buf[0] != 0x0) { MBEDTLS_SSL_DEBUG_MSG(1, ("non-zero length renegotiation info")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION; } return 0; } #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) /* * Status of the implementation of signature-algorithms extension: * * Currently, we are only considering the signature-algorithm extension * to pick a ciphersuite which allows us to send the ServerKeyExchange * message with a signature-hash combination that the user allows. * * We do *not* check whether all certificates in our certificate * chain are signed with an allowed signature-hash pair. * This needs to be done at a later stage. * */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_signature_algorithms_ext(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { size_t sig_alg_list_size; const unsigned char *p; const unsigned char *end = buf + len; mbedtls_md_type_t md_cur; mbedtls_pk_type_t sig_cur; if (len < 2) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } sig_alg_list_size = ((buf[0] << 8) | (buf[1])); if (sig_alg_list_size + 2 != len || sig_alg_list_size % 2 != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* Currently we only guarantee signing the ServerKeyExchange message according * to the constraints specified in this extension (see above), so it suffices * to remember only one suitable hash for each possible signature algorithm. * * This will change when we also consider certificate signatures, * in which case we will need to remember the whole signature-hash * pair list from the extension. */ for (p = buf + 2; p < end; p += 2) { /* Silently ignore unknown signature or hash algorithms. */ if ((sig_cur = mbedtls_ssl_pk_alg_from_sig(p[1])) == MBEDTLS_PK_NONE) { MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, signature_algorithm ext" " unknown sig alg encoding %d", p[1])); continue; } /* Check if we support the hash the user proposes */ md_cur = mbedtls_ssl_md_alg_from_hash(p[0]); if (md_cur == MBEDTLS_MD_NONE) { MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, signature_algorithm ext:" " unknown hash alg encoding %d", p[0])); continue; } if (mbedtls_ssl_check_sig_hash(ssl, md_cur) == 0) { mbedtls_ssl_sig_hash_set_add(&ssl->handshake->hash_algs, sig_cur, md_cur); MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, signature_algorithm ext:" " match sig %u and hash %u", (unsigned) sig_cur, (unsigned) md_cur)); } else { MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, signature_algorithm ext: " "hash alg %u not supported", (unsigned) md_cur)); } } return 0; } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \ defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_supported_elliptic_curves(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { size_t list_size, our_size; const unsigned char *p; const mbedtls_ecp_curve_info *curve_info, **curves; if (len < 2) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } list_size = ((buf[0] << 8) | (buf[1])); if (list_size + 2 != len || list_size % 2 != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* Should never happen unless client duplicates the extension */ if (ssl->handshake->curves != NULL) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* Don't allow our peer to make us allocate too much memory, * and leave room for a final 0 */ our_size = list_size / 2 + 1; if (our_size > MBEDTLS_ECP_DP_MAX) { our_size = MBEDTLS_ECP_DP_MAX; } if ((curves = mbedtls_calloc(our_size, sizeof(*curves))) == NULL) { mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR); return MBEDTLS_ERR_SSL_ALLOC_FAILED; } ssl->handshake->curves = curves; p = buf + 2; while (list_size > 0 && our_size > 1) { curve_info = mbedtls_ecp_curve_info_from_tls_id((p[0] << 8) | p[1]); if (curve_info != NULL) { *curves++ = curve_info; our_size--; } list_size -= 2; p += 2; } return 0; } MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_supported_point_formats(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { size_t list_size; const unsigned char *p; if (len == 0 || (size_t) (buf[0] + 1) != len) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } list_size = buf[0]; p = buf + 1; while (list_size > 0) { if (p[0] == MBEDTLS_ECP_PF_UNCOMPRESSED || p[0] == MBEDTLS_ECP_PF_COMPRESSED) { #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) ssl->handshake->ecdh_ctx.point_format = p[0]; #endif #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) ssl->handshake->ecjpake_ctx.point_format = p[0]; #endif MBEDTLS_SSL_DEBUG_MSG(4, ("point format selected: %d", p[0])); return 0; } list_size--; p++; } return 0; } #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_ecjpake_kkpp(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; if (mbedtls_ecjpake_check(&ssl->handshake->ecjpake_ctx) != 0) { MBEDTLS_SSL_DEBUG_MSG(3, ("skip ecjpake kkpp extension")); return 0; } if ((ret = mbedtls_ecjpake_read_round_one(&ssl->handshake->ecjpake_ctx, buf, len)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_read_round_one", ret); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER); return ret; } /* Only mark the extension as OK when we're sure it is */ ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK; return 0; } #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_max_fragment_length_ext(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { if (len != 1 || buf[0] >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ssl->session_negotiate->mfl_code = buf[0]; return 0; } #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */ #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_cid_ext(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { size_t peer_cid_len; /* CID extension only makes sense in DTLS */ if (ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* * Quoting draft-ietf-tls-dtls-connection-id-05 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05 * * struct { * opaque cid<0..2^8-1>; * } ConnectionId; */ if (len < 1) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } peer_cid_len = *buf++; len--; if (len != peer_cid_len) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* Ignore CID if the user has disabled its use. */ if (ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED) { /* Leave ssl->handshake->cid_in_use in its default * value of MBEDTLS_SSL_CID_DISABLED. */ MBEDTLS_SSL_DEBUG_MSG(3, ("Client sent CID extension, but CID disabled")); return 0; } if (peer_cid_len > MBEDTLS_SSL_CID_OUT_LEN_MAX) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ssl->handshake->cid_in_use = MBEDTLS_SSL_CID_ENABLED; ssl->handshake->peer_cid_len = (uint8_t) peer_cid_len; memcpy(ssl->handshake->peer_cid, buf, peer_cid_len); MBEDTLS_SSL_DEBUG_MSG(3, ("Use of CID extension negotiated")); MBEDTLS_SSL_DEBUG_BUF(3, "Client CID", buf, peer_cid_len); return 0; } #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ #if defined(MBEDTLS_SSL_TRUNCATED_HMAC) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_truncated_hmac_ext(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { if (len != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ((void) buf); if (ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_ENABLED) { ssl->session_negotiate->trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_ENABLED; } return 0; } #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */ #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_encrypt_then_mac_ext(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { if (len != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ((void) buf); if (ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED && ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0) { ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_ENABLED; } return 0; } #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_extended_ms_ext(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { if (len != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ((void) buf); if (ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED && ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0) { ssl->handshake->extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED; } return 0; } #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_session_ticket_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t len) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; mbedtls_ssl_session session; mbedtls_ssl_session_init(&session); if (ssl->conf->f_ticket_parse == NULL || ssl->conf->f_ticket_write == NULL) { return 0; } /* Remember the client asked us to send a new ticket */ ssl->handshake->new_session_ticket = 1; MBEDTLS_SSL_DEBUG_MSG(3, ("ticket length: %" MBEDTLS_PRINTF_SIZET, len)); if (len == 0) { return 0; } #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) { MBEDTLS_SSL_DEBUG_MSG(3, ("ticket rejected: renegotiating")); return 0; } #endif /* MBEDTLS_SSL_RENEGOTIATION */ /* * Failures are ok: just ignore the ticket and proceed. */ if ((ret = ssl->conf->f_ticket_parse(ssl->conf->p_ticket, &session, buf, len)) != 0) { mbedtls_ssl_session_free(&session); if (ret == MBEDTLS_ERR_SSL_INVALID_MAC) { MBEDTLS_SSL_DEBUG_MSG(3, ("ticket is not authentic")); } else if (ret == MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED) { MBEDTLS_SSL_DEBUG_MSG(3, ("ticket is expired")); } else { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_ticket_parse", ret); } return 0; } /* * Keep the session ID sent by the client, since we MUST send it back to * inform them we're accepting the ticket (RFC 5077 section 3.4) */ session.id_len = ssl->session_negotiate->id_len; memcpy(&session.id, ssl->session_negotiate->id, session.id_len); mbedtls_ssl_session_free(ssl->session_negotiate); memcpy(ssl->session_negotiate, &session, sizeof(mbedtls_ssl_session)); /* Zeroize instead of free as we copied the content */ mbedtls_platform_zeroize(&session, sizeof(mbedtls_ssl_session)); MBEDTLS_SSL_DEBUG_MSG(3, ("session successfully restored from ticket")); ssl->handshake->resume = 1; /* Don't send a new ticket after all, this one is OK */ ssl->handshake->new_session_ticket = 0; return 0; } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ #if defined(MBEDTLS_SSL_ALPN) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_alpn_ext(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { size_t list_len, cur_len, ours_len; const unsigned char *theirs, *start, *end; const char **ours; /* If ALPN not configured, just ignore the extension */ if (ssl->conf->alpn_list == NULL) { return 0; } /* * opaque ProtocolName<1..2^8-1>; * * struct { * ProtocolName protocol_name_list<2..2^16-1> * } ProtocolNameList; */ /* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */ if (len < 4) { mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } list_len = (buf[0] << 8) | buf[1]; if (list_len != len - 2) { mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* * Validate peer's list (lengths) */ start = buf + 2; end = buf + len; for (theirs = start; theirs != end; theirs += cur_len) { cur_len = *theirs++; /* Current identifier must fit in list */ if (cur_len > (size_t) (end - theirs)) { mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* Empty strings MUST NOT be included */ if (cur_len == 0) { mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } } /* * Use our order of preference */ for (ours = ssl->conf->alpn_list; *ours != NULL; ours++) { ours_len = strlen(*ours); for (theirs = start; theirs != end; theirs += cur_len) { cur_len = *theirs++; if (cur_len == ours_len && memcmp(theirs, *ours, cur_len) == 0) { ssl->alpn_chosen = *ours; return 0; } } } /* If we get there, no match was found */ mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } #endif /* MBEDTLS_SSL_ALPN */ #if defined(MBEDTLS_SSL_DTLS_SRTP) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_use_srtp_ext(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len) { mbedtls_ssl_srtp_profile client_protection = MBEDTLS_TLS_SRTP_UNSET; size_t i, j; size_t profile_length; uint16_t mki_length; /*! 2 bytes for profile length and 1 byte for mki len */ const size_t size_of_lengths = 3; /* If use_srtp is not configured, just ignore the extension */ if ((ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM) || (ssl->conf->dtls_srtp_profile_list == NULL) || (ssl->conf->dtls_srtp_profile_list_len == 0)) { return 0; } /* RFC5764 section 4.1.1 * uint8 SRTPProtectionProfile[2]; * * struct { * SRTPProtectionProfiles SRTPProtectionProfiles; * opaque srtp_mki<0..255>; * } UseSRTPData; * SRTPProtectionProfile SRTPProtectionProfiles<2..2^16-1>; */ /* * Min length is 5: at least one protection profile(2 bytes) * and length(2 bytes) + srtp_mki length(1 byte) * Check here that we have at least 2 bytes of protection profiles length * and one of srtp_mki length */ if (len < size_of_lengths) { mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ssl->dtls_srtp_info.chosen_dtls_srtp_profile = MBEDTLS_TLS_SRTP_UNSET; /* first 2 bytes are protection profile length(in bytes) */ profile_length = (buf[0] << 8) | buf[1]; buf += 2; /* The profile length cannot be bigger than input buffer size - lengths fields */ if (profile_length > len - size_of_lengths || profile_length % 2 != 0) { /* profiles are 2 bytes long, so the length must be even */ mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* * parse the extension list values are defined in * http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml */ for (j = 0; j < profile_length; j += 2) { uint16_t protection_profile_value = buf[j] << 8 | buf[j + 1]; client_protection = mbedtls_ssl_check_srtp_profile_value(protection_profile_value); if (client_protection != MBEDTLS_TLS_SRTP_UNSET) { MBEDTLS_SSL_DEBUG_MSG(3, ("found srtp profile: %s", mbedtls_ssl_get_srtp_profile_as_string( client_protection))); } else { continue; } /* check if suggested profile is in our list */ for (i = 0; i < ssl->conf->dtls_srtp_profile_list_len; i++) { if (client_protection == ssl->conf->dtls_srtp_profile_list[i]) { ssl->dtls_srtp_info.chosen_dtls_srtp_profile = ssl->conf->dtls_srtp_profile_list[i]; MBEDTLS_SSL_DEBUG_MSG(3, ("selected srtp profile: %s", mbedtls_ssl_get_srtp_profile_as_string( client_protection))); break; } } if (ssl->dtls_srtp_info.chosen_dtls_srtp_profile != MBEDTLS_TLS_SRTP_UNSET) { break; } } buf += profile_length; /* buf points to the mki length */ mki_length = *buf; buf++; if (mki_length > MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH || mki_length + profile_length + size_of_lengths != len) { mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* Parse the mki only if present and mki is supported locally */ if (ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED && mki_length > 0) { ssl->dtls_srtp_info.mki_len = mki_length; memcpy(ssl->dtls_srtp_info.mki_value, buf, mki_length); MBEDTLS_SSL_DEBUG_BUF(3, "using mki", ssl->dtls_srtp_info.mki_value, ssl->dtls_srtp_info.mki_len); } return 0; } #endif /* MBEDTLS_SSL_DTLS_SRTP */ /* * Auxiliary functions for ServerHello parsing and related actions */ #if defined(MBEDTLS_X509_CRT_PARSE_C) /* * Return 0 if the given key uses one of the acceptable curves, -1 otherwise */ #if defined(MBEDTLS_ECDSA_C) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_check_key_curve(mbedtls_pk_context *pk, const mbedtls_ecp_curve_info **curves) { const mbedtls_ecp_curve_info **crv = curves; mbedtls_ecp_group_id grp_id = mbedtls_pk_ec(*pk)->grp.id; while (*crv != NULL) { if ((*crv)->grp_id == grp_id) { return 0; } crv++; } return -1; } #endif /* MBEDTLS_ECDSA_C */ /* * Try picking a certificate for this ciphersuite, * return 0 on success and -1 on failure. */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_pick_cert(mbedtls_ssl_context *ssl, const mbedtls_ssl_ciphersuite_t *ciphersuite_info) { mbedtls_ssl_key_cert *cur, *list, *fallback = NULL; mbedtls_pk_type_t pk_alg = mbedtls_ssl_get_ciphersuite_sig_pk_alg(ciphersuite_info); uint32_t flags; #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) if (ssl->handshake->sni_key_cert != NULL) { list = ssl->handshake->sni_key_cert; } else #endif list = ssl->conf->key_cert; if (pk_alg == MBEDTLS_PK_NONE) { return 0; } MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite requires certificate")); if (list == NULL) { MBEDTLS_SSL_DEBUG_MSG(3, ("server has no certificate")); return -1; } for (cur = list; cur != NULL; cur = cur->next) { flags = 0; MBEDTLS_SSL_DEBUG_CRT(3, "candidate certificate chain, certificate", cur->cert); if (!mbedtls_pk_can_do(&cur->cert->pk, pk_alg)) { MBEDTLS_SSL_DEBUG_MSG(3, ("certificate mismatch: key type")); continue; } /* * This avoids sending the client a cert it'll reject based on * keyUsage or other extensions. * * It also allows the user to provision different certificates for * different uses based on keyUsage, eg if they want to avoid signing * and decrypting with the same RSA key. */ if (mbedtls_ssl_check_cert_usage(cur->cert, ciphersuite_info, MBEDTLS_SSL_IS_SERVER, &flags) != 0) { MBEDTLS_SSL_DEBUG_MSG(3, ("certificate mismatch: " "(extended) key usage extension")); continue; } #if defined(MBEDTLS_ECDSA_C) if (pk_alg == MBEDTLS_PK_ECDSA && ssl_check_key_curve(&cur->cert->pk, ssl->handshake->curves) != 0) { MBEDTLS_SSL_DEBUG_MSG(3, ("certificate mismatch: elliptic curve")); continue; } #endif /* * Try to select a SHA-1 certificate for pre-1.2 clients, but still * present them a SHA-higher cert rather than failing if it's the only * one we got that satisfies the other conditions. */ if (ssl->minor_ver < MBEDTLS_SSL_MINOR_VERSION_3 && cur->cert->sig_md != MBEDTLS_MD_SHA1) { if (fallback == NULL) { fallback = cur; } { MBEDTLS_SSL_DEBUG_MSG(3, ("certificate not preferred: " "sha-2 with pre-TLS 1.2 client")); continue; } } /* If we get there, we got a winner */ break; } if (cur == NULL) { cur = fallback; } /* Do not update ssl->handshake->key_cert unless there is a match */ if (cur != NULL) { ssl->handshake->key_cert = cur; MBEDTLS_SSL_DEBUG_CRT(3, "selected certificate chain, certificate", ssl->handshake->key_cert->cert); return 0; } return -1; } #endif /* MBEDTLS_X509_CRT_PARSE_C */ /* * Check if a given ciphersuite is suitable for use with our config/keys/etc * Sets ciphersuite_info only if the suite matches. */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_ciphersuite_match(mbedtls_ssl_context *ssl, int suite_id, const mbedtls_ssl_ciphersuite_t **ciphersuite_info) { const mbedtls_ssl_ciphersuite_t *suite_info; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) mbedtls_pk_type_t sig_type; #endif suite_info = mbedtls_ssl_ciphersuite_from_id(suite_id); if (suite_info == NULL) { MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } MBEDTLS_SSL_DEBUG_MSG(3, ("trying ciphersuite: %#04x (%s)", (unsigned int) suite_id, suite_info->name)); if (suite_info->min_minor_ver > ssl->minor_ver || suite_info->max_minor_ver < ssl->minor_ver) { MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: version")); return 0; } #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && (suite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS)) { return 0; } #endif #if defined(MBEDTLS_ARC4_C) if (ssl->conf->arc4_disabled == MBEDTLS_SSL_ARC4_DISABLED && suite_info->cipher == MBEDTLS_CIPHER_ARC4_128) { MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: rc4")); return 0; } #endif #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) if (suite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE && (ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK) == 0) { MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: ecjpake " "not configured or ext missing")); return 0; } #endif #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) if (mbedtls_ssl_ciphersuite_uses_ec(suite_info) && (ssl->handshake->curves == NULL || ssl->handshake->curves[0] == NULL)) { MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: " "no common elliptic curve")); return 0; } #endif #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED) /* If the ciphersuite requires a pre-shared key and we don't * have one, skip it now rather than failing later */ if (mbedtls_ssl_ciphersuite_uses_psk(suite_info) && ssl_conf_has_psk_or_cb(ssl->conf) == 0) { MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: no pre-shared key")); return 0; } #endif #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) /* If the ciphersuite requires signing, check whether * a suitable hash algorithm is present. */ if (ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3) { sig_type = mbedtls_ssl_get_ciphersuite_sig_alg(suite_info); if (sig_type != MBEDTLS_PK_NONE && mbedtls_ssl_sig_hash_set_find(&ssl->handshake->hash_algs, sig_type) == MBEDTLS_MD_NONE) { MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: no suitable hash algorithm " "for signature algorithm %u", (unsigned) sig_type)); return 0; } } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ #if defined(MBEDTLS_X509_CRT_PARSE_C) /* * Final check: if ciphersuite requires us to have a * certificate/key of a particular type: * - select the appropriate certificate if we have one, or * - try the next ciphersuite if we don't * This must be done last since we modify the key_cert list. */ if (ssl_pick_cert(ssl, suite_info) != 0) { MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: " "no suitable certificate")); return 0; } #endif *ciphersuite_info = suite_info; return 0; } #if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_client_hello_v2(mbedtls_ssl_context *ssl) { int ret, got_common_suite; unsigned int i, j; size_t n; unsigned int ciph_len, sess_len, chal_len; unsigned char *buf, *p; const int *ciphersuites; const mbedtls_ssl_ciphersuite_t *ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse client hello v2")); #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) { MBEDTLS_SSL_DEBUG_MSG(1, ("client hello v2 illegal for renegotiation")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } #endif /* MBEDTLS_SSL_RENEGOTIATION */ buf = ssl->in_hdr; MBEDTLS_SSL_DEBUG_BUF(4, "record header", buf, 5); MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v2, message type: %d", buf[2])); MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v2, message len.: %d", ((buf[0] & 0x7F) << 8) | buf[1])); MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v2, max. version: [%d:%d]", buf[3], buf[4])); /* * SSLv2 Client Hello * * Record layer: * 0 . 1 message length * * SSL layer: * 2 . 2 message type * 3 . 4 protocol version */ if (buf[2] != MBEDTLS_SSL_HS_CLIENT_HELLO || buf[3] != MBEDTLS_SSL_MAJOR_VERSION_3) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } n = ((buf[0] << 8) | buf[1]) & 0x7FFF; if (n < 17 || n > 512) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ssl->major_ver = MBEDTLS_SSL_MAJOR_VERSION_3; ssl->minor_ver = (buf[4] <= ssl->conf->max_minor_ver) ? buf[4] : ssl->conf->max_minor_ver; if (ssl->minor_ver < ssl->conf->min_minor_ver) { MBEDTLS_SSL_DEBUG_MSG(1, ("client only supports ssl smaller than minimum" " [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver, ssl->conf->min_major_ver, ssl->conf->min_minor_ver)); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION); return MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION; } ssl->handshake->max_major_ver = buf[3]; ssl->handshake->max_minor_ver = buf[4]; if ((ret = mbedtls_ssl_fetch_input(ssl, 2 + n)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_fetch_input", ret); return ret; } ssl->handshake->update_checksum(ssl, buf + 2, n); buf = ssl->in_msg; n = ssl->in_left - 5; /* * 0 . 1 ciphersuitelist length * 2 . 3 session id length * 4 . 5 challenge length * 6 . .. ciphersuitelist * .. . .. session id * .. . .. challenge */ MBEDTLS_SSL_DEBUG_BUF(4, "record contents", buf, n); ciph_len = (buf[0] << 8) | buf[1]; sess_len = (buf[2] << 8) | buf[3]; chal_len = (buf[4] << 8) | buf[5]; MBEDTLS_SSL_DEBUG_MSG(3, ("ciph_len: %u, sess_len: %u, chal_len: %u", ciph_len, sess_len, chal_len)); /* * Make sure each parameter length is valid */ if (ciph_len < 3 || (ciph_len % 3) != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } if (sess_len > 32) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } if (chal_len < 8 || chal_len > 32) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } if (n != 6 + ciph_len + sess_len + chal_len) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } MBEDTLS_SSL_DEBUG_BUF(3, "client hello, ciphersuitelist", buf + 6, ciph_len); MBEDTLS_SSL_DEBUG_BUF(3, "client hello, session id", buf + 6 + ciph_len, sess_len); MBEDTLS_SSL_DEBUG_BUF(3, "client hello, challenge", buf + 6 + ciph_len + sess_len, chal_len); p = buf + 6 + ciph_len; ssl->session_negotiate->id_len = sess_len; memset(ssl->session_negotiate->id, 0, sizeof(ssl->session_negotiate->id)); memcpy(ssl->session_negotiate->id, p, ssl->session_negotiate->id_len); p += sess_len; memset(ssl->handshake->randbytes, 0, 64); memcpy(ssl->handshake->randbytes + 32 - chal_len, p, chal_len); /* * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */ for (i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3) { if (p[0] == 0 && p[1] == 0 && p[2] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO) { MBEDTLS_SSL_DEBUG_MSG(3, ("received TLS_EMPTY_RENEGOTIATION_INFO ")); #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS) { MBEDTLS_SSL_DEBUG_MSG(1, ("received RENEGOTIATION SCSV " "during renegotiation")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } #endif /* MBEDTLS_SSL_RENEGOTIATION */ ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION; break; } } #if defined(MBEDTLS_SSL_FALLBACK_SCSV) for (i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3) { if (p[0] == 0 && MBEDTLS_GET_UINT16_BE(p, 1) != MBEDTLS_SSL_FALLBACK_SCSV_VALUE) { MBEDTLS_SSL_DEBUG_MSG(3, ("received FALLBACK_SCSV")); if (ssl->minor_ver < ssl->conf->max_minor_ver) { MBEDTLS_SSL_DEBUG_MSG(1, ("inapropriate fallback")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } break; } } #endif /* MBEDTLS_SSL_FALLBACK_SCSV */ got_common_suite = 0; ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver]; ciphersuite_info = NULL; #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE) for (j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3) { for (i = 0; ciphersuites[i] != 0; i++) { if (p[0] != 0 || MBEDTLS_GET_UINT16_BE(p, 1) != ciphersuites[i]) { continue; } got_common_suite = 1; if ((ret = ssl_ciphersuite_match(ssl, ciphersuites[i], &ciphersuite_info)) != 0) { return ret; } if (ciphersuite_info != NULL) { goto have_ciphersuite_v2; } } } #else for (i = 0; ciphersuites[i] != 0; i++) { for (j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3) { if (p[0] != 0 || MBEDTLS_GET_UINT16_BE(p, 1) != ciphersuites[i]) { continue; } got_common_suite = 1; if ((ret = ssl_ciphersuite_match(ssl, ciphersuites[i], &ciphersuite_info)) != 0) { return ret; } if (ciphersuite_info != NULL) { goto have_ciphersuite_v2; } } } #endif if (got_common_suite) { MBEDTLS_SSL_DEBUG_MSG(1, ("got ciphersuites in common, " "but none of them usable")); return MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE; } else { MBEDTLS_SSL_DEBUG_MSG(1, ("got no ciphersuites in common")); return MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN; } have_ciphersuite_v2: MBEDTLS_SSL_DEBUG_MSG(2, ("selected ciphersuite: %s", ciphersuite_info->name)); ssl->session_negotiate->ciphersuite = ciphersuites[i]; ssl->handshake->ciphersuite_info = ciphersuite_info; /* * SSLv2 Client Hello relevant renegotiation security checks */ if (ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION && ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE) { MBEDTLS_SSL_DEBUG_MSG(1, ("legacy renegotiation, breaking off handshake")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ssl->in_left = 0; ssl->state++; MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse client hello v2")); return 0; } #endif /* MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */ /* This function doesn't alert on errors that happen early during ClientHello parsing because they might indicate that the client is not talking SSL/TLS at all and would not understand our alert. */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_client_hello(mbedtls_ssl_context *ssl) { int ret, got_common_suite; size_t i, j; size_t ciph_offset, comp_offset, ext_offset; size_t msg_len, ciph_len, sess_len, comp_len, ext_len; #if defined(MBEDTLS_SSL_PROTO_DTLS) size_t cookie_offset, cookie_len; #endif unsigned char *buf, *p, *ext; #if defined(MBEDTLS_SSL_RENEGOTIATION) int renegotiation_info_seen = 0; #endif int handshake_failure = 0; const int *ciphersuites; const mbedtls_ssl_ciphersuite_t *ciphersuite_info; int major, minor; /* If there is no signature-algorithm extension present, * we need to fall back to the default values for allowed * signature-hash pairs. */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) int sig_hash_alg_ext_present = 0; #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse client hello")); int renegotiating = 0; #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) read_record_header: #endif /* * If renegotiating, then the input was read with mbedtls_ssl_read_record(), * otherwise read it ourselves manually in order to support SSLv2 * ClientHello, which doesn't use the same record layer format. */ #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) { renegotiating = 1; } #endif if (!renegotiating) { if ((ret = mbedtls_ssl_fetch_input(ssl, 5)) != 0) { /* No alert on a read error. */ MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_fetch_input", ret); return ret; } } buf = ssl->in_hdr; #if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO) int is_dtls = 0; #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) { is_dtls = 1; } #endif if (!is_dtls) { if ((buf[0] & 0x80) != 0) { return ssl_parse_client_hello_v2(ssl); } } #endif MBEDTLS_SSL_DEBUG_BUF(4, "record header", buf, mbedtls_ssl_in_hdr_len(ssl)); /* * SSLv3/TLS Client Hello * * Record layer: * 0 . 0 message type * 1 . 2 protocol version * 3 . 11 DTLS: epoch + record sequence number * 3 . 4 message length */ MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, message type: %d", buf[0])); if (buf[0] != MBEDTLS_SSL_MSG_HANDSHAKE) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, message len.: %d", (ssl->in_len[0] << 8) | ssl->in_len[1])); MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, protocol version: [%d:%d]", buf[1], buf[2])); mbedtls_ssl_read_version(&major, &minor, ssl->conf->transport, buf + 1); /* According to RFC 5246 Appendix E.1, the version here is typically * "{03,00}, the lowest version number supported by the client, [or] the * value of ClientHello.client_version", so the only meaningful check here * is the major version shouldn't be less than 3 */ if (major < MBEDTLS_SSL_MAJOR_VERSION_3) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* For DTLS if this is the initial handshake, remember the client sequence * number to use it in our next message (RFC 6347 4.2.1) */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM #if defined(MBEDTLS_SSL_RENEGOTIATION) && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE #endif ) { /* Epoch should be 0 for initial handshakes */ if (ssl->in_ctr[0] != 0 || ssl->in_ctr[1] != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } memcpy(ssl->cur_out_ctr + 2, ssl->in_ctr + 2, 6); #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) if (mbedtls_ssl_dtls_replay_check(ssl) != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("replayed record, discarding")); ssl->next_record_offset = 0; ssl->in_left = 0; goto read_record_header; } /* No MAC to check yet, so we can update right now */ mbedtls_ssl_dtls_replay_update(ssl); #endif } #endif /* MBEDTLS_SSL_PROTO_DTLS */ msg_len = (ssl->in_len[0] << 8) | ssl->in_len[1]; #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) { /* Set by mbedtls_ssl_read_record() */ msg_len = ssl->in_hslen; } else #endif { if (msg_len > MBEDTLS_SSL_IN_CONTENT_LEN) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } if ((ret = mbedtls_ssl_fetch_input(ssl, mbedtls_ssl_in_hdr_len(ssl) + msg_len)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_fetch_input", ret); return ret; } /* Done reading this record, get ready for the next one */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) { ssl->next_record_offset = msg_len + mbedtls_ssl_in_hdr_len(ssl); } else #endif ssl->in_left = 0; } buf = ssl->in_msg; MBEDTLS_SSL_DEBUG_BUF(4, "record contents", buf, msg_len); ssl->handshake->update_checksum(ssl, buf, msg_len); /* * Handshake layer: * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 5 DTLS only: message sequence number * 6 . 8 DTLS only: fragment offset * 9 . 11 DTLS only: fragment length */ if (msg_len < mbedtls_ssl_hs_hdr_len(ssl)) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, handshake type: %d", buf[0])); if (buf[0] != MBEDTLS_SSL_HS_CLIENT_HELLO) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, handshake len.: %d", (buf[1] << 16) | (buf[2] << 8) | buf[3])); if (buf[1] != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message: %u != 0", (unsigned) buf[1])); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* We don't support fragmentation of ClientHello (yet?) */ if (msg_len != mbedtls_ssl_hs_hdr_len(ssl) + ((buf[2] << 8) | buf[3])) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message: %u != %u + %u", (unsigned) msg_len, (unsigned) mbedtls_ssl_hs_hdr_len(ssl), (unsigned) (buf[2] << 8) | buf[3])); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) { /* * Copy the client's handshake message_seq on initial handshakes, * check sequence number on renego. */ #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS) { /* This couldn't be done in ssl_prepare_handshake_record() */ unsigned int cli_msg_seq = (ssl->in_msg[4] << 8) | ssl->in_msg[5]; if (cli_msg_seq != ssl->handshake->in_msg_seq) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message_seq: " "%u (expected %u)", cli_msg_seq, ssl->handshake->in_msg_seq)); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ssl->handshake->in_msg_seq++; } else #endif { unsigned int cli_msg_seq = (ssl->in_msg[4] << 8) | ssl->in_msg[5]; ssl->handshake->out_msg_seq = cli_msg_seq; ssl->handshake->in_msg_seq = cli_msg_seq + 1; } /* * For now we don't support fragmentation, so make sure * fragment_offset == 0 and fragment_length == length */ MBEDTLS_SSL_DEBUG_MSG( 4, ("fragment_offset=%u fragment_length=%u length=%u", (unsigned) (ssl->in_msg[6] << 16 | ssl->in_msg[7] << 8 | ssl->in_msg[8]), (unsigned) (ssl->in_msg[9] << 16 | ssl->in_msg[10] << 8 | ssl->in_msg[11]), (unsigned) (ssl->in_msg[1] << 16 | ssl->in_msg[2] << 8 | ssl->in_msg[3]))); if (ssl->in_msg[6] != 0 || ssl->in_msg[7] != 0 || ssl->in_msg[8] != 0 || memcmp(ssl->in_msg + 1, ssl->in_msg + 9, 3) != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("ClientHello fragmentation not supported")); return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; } } #endif /* MBEDTLS_SSL_PROTO_DTLS */ buf += mbedtls_ssl_hs_hdr_len(ssl); msg_len -= mbedtls_ssl_hs_hdr_len(ssl); /* * ClientHello layer: * 0 . 1 protocol version * 2 . 33 random bytes (starting with 4 bytes of Unix time) * 34 . 35 session id length (1 byte) * 35 . 34+x session id * 35+x . 35+x DTLS only: cookie length (1 byte) * 36+x . .. DTLS only: cookie * .. . .. 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. */ if (msg_len < 38) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* * Check and save the protocol version */ MBEDTLS_SSL_DEBUG_BUF(3, "client hello, version", buf, 2); mbedtls_ssl_read_version(&ssl->major_ver, &ssl->minor_ver, ssl->conf->transport, buf); ssl->handshake->max_major_ver = ssl->major_ver; ssl->handshake->max_minor_ver = ssl->minor_ver; if (ssl->major_ver < ssl->conf->min_major_ver || ssl->minor_ver < ssl->conf->min_minor_ver) { MBEDTLS_SSL_DEBUG_MSG(1, ("client only supports ssl smaller than minimum" " [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver, ssl->conf->min_major_ver, ssl->conf->min_minor_ver)); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION); return MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION; } if (ssl->major_ver > ssl->conf->max_major_ver) { ssl->major_ver = ssl->conf->max_major_ver; ssl->minor_ver = ssl->conf->max_minor_ver; } else if (ssl->minor_ver > ssl->conf->max_minor_ver) { ssl->minor_ver = ssl->conf->max_minor_ver; } /* * Save client random (inc. Unix time) */ MBEDTLS_SSL_DEBUG_BUF(3, "client hello, random bytes", buf + 2, 32); memcpy(ssl->handshake->randbytes, buf + 2, 32); /* * Check the session ID length and save session ID */ sess_len = buf[34]; if (sess_len > sizeof(ssl->session_negotiate->id) || sess_len + 34 + 2 > msg_len) { /* 2 for cipherlist length field */ MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } MBEDTLS_SSL_DEBUG_BUF(3, "client hello, session id", buf + 35, sess_len); ssl->session_negotiate->id_len = sess_len; memset(ssl->session_negotiate->id, 0, sizeof(ssl->session_negotiate->id)); memcpy(ssl->session_negotiate->id, buf + 35, ssl->session_negotiate->id_len); /* * Check the cookie length and content */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) { cookie_offset = 35 + sess_len; cookie_len = buf[cookie_offset]; if (cookie_offset + 1 + cookie_len + 2 > msg_len) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } MBEDTLS_SSL_DEBUG_BUF(3, "client hello, cookie", buf + cookie_offset + 1, cookie_len); #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) if (ssl->conf->f_cookie_check != NULL #if defined(MBEDTLS_SSL_RENEGOTIATION) && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE #endif ) { if (ssl->conf->f_cookie_check(ssl->conf->p_cookie, buf + cookie_offset + 1, cookie_len, ssl->cli_id, ssl->cli_id_len) != 0) { MBEDTLS_SSL_DEBUG_MSG(2, ("cookie verification failed")); ssl->handshake->verify_cookie_len = 1; } else { MBEDTLS_SSL_DEBUG_MSG(2, ("cookie verification passed")); ssl->handshake->verify_cookie_len = 0; } } else #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */ { /* We know we didn't send a cookie, so it should be empty */ if (cookie_len != 0) { /* This may be an attacker's probe, so don't send an alert */ MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } MBEDTLS_SSL_DEBUG_MSG(2, ("cookie verification skipped")); } /* * Check the ciphersuitelist length (will be parsed later) */ ciph_offset = cookie_offset + 1 + cookie_len; } else #endif /* MBEDTLS_SSL_PROTO_DTLS */ ciph_offset = 35 + sess_len; ciph_len = (buf[ciph_offset + 0] << 8) | (buf[ciph_offset + 1]); if (ciph_len < 2 || ciph_len + 2 + ciph_offset + 1 > msg_len || /* 1 for comp. alg. len */ (ciph_len % 2) != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } MBEDTLS_SSL_DEBUG_BUF(3, "client hello, ciphersuitelist", buf + ciph_offset + 2, ciph_len); /* * Check the compression algorithms length and pick one */ comp_offset = ciph_offset + 2 + ciph_len; comp_len = buf[comp_offset]; if (comp_len < 1 || comp_len > 16 || comp_len + comp_offset + 1 > msg_len) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } MBEDTLS_SSL_DEBUG_BUF(3, "client hello, compression", buf + comp_offset + 1, comp_len); ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL; #if defined(MBEDTLS_ZLIB_SUPPORT) for (i = 0; i < comp_len; ++i) { if (buf[comp_offset + 1 + i] == MBEDTLS_SSL_COMPRESS_DEFLATE) { ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_DEFLATE; break; } } #endif /* See comments in ssl_write_client_hello() */ #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) { ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL; } #endif /* Do not parse the extensions if the protocol is SSLv3 */ #if defined(MBEDTLS_SSL_PROTO_SSL3) if ((ssl->major_ver != 3) || (ssl->minor_ver != 0)) { #endif /* * Check the extension length */ ext_offset = comp_offset + 1 + comp_len; if (msg_len > ext_offset) { if (msg_len < ext_offset + 2) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ext_len = (buf[ext_offset + 0] << 8) | (buf[ext_offset + 1]); if (msg_len != ext_offset + 2 + ext_len) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } } else { ext_len = 0; } ext = buf + ext_offset + 2; MBEDTLS_SSL_DEBUG_BUF(3, "client hello extensions", ext, ext_len); while (ext_len != 0) { unsigned int ext_id; unsigned int ext_size; if (ext_len < 4) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } ext_id = ((ext[0] << 8) | (ext[1])); ext_size = ((ext[2] << 8) | (ext[3])); if (ext_size + 4 > ext_len) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } switch (ext_id) { #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) case MBEDTLS_TLS_EXT_SERVERNAME: MBEDTLS_SSL_DEBUG_MSG(3, ("found ServerName extension")); if (ssl->conf->f_sni == NULL) { break; } ret = ssl_parse_servername_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */ case MBEDTLS_TLS_EXT_RENEGOTIATION_INFO: MBEDTLS_SSL_DEBUG_MSG(3, ("found renegotiation extension")); #if defined(MBEDTLS_SSL_RENEGOTIATION) renegotiation_info_seen = 1; #endif ret = ssl_parse_renegotiation_info(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) case MBEDTLS_TLS_EXT_SIG_ALG: MBEDTLS_SSL_DEBUG_MSG(3, ("found signature_algorithms extension")); ret = ssl_parse_signature_algorithms_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } sig_hash_alg_ext_present = 1; break; #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \ defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) case MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES: MBEDTLS_SSL_DEBUG_MSG(3, ("found supported elliptic curves extension")); ret = ssl_parse_supported_elliptic_curves(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; case MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS: MBEDTLS_SSL_DEBUG_MSG(3, ("found supported point formats extension")); ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT; ret = ssl_parse_supported_point_formats(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) case MBEDTLS_TLS_EXT_ECJPAKE_KKPP: MBEDTLS_SSL_DEBUG_MSG(3, ("found ecjpake kkpp extension")); ret = ssl_parse_ecjpake_kkpp(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) case MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH: MBEDTLS_SSL_DEBUG_MSG(3, ("found max fragment length extension")); ret = ssl_parse_max_fragment_length_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */ #if defined(MBEDTLS_SSL_TRUNCATED_HMAC) case MBEDTLS_TLS_EXT_TRUNCATED_HMAC: MBEDTLS_SSL_DEBUG_MSG(3, ("found truncated hmac extension")); ret = ssl_parse_truncated_hmac_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */ #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) case MBEDTLS_TLS_EXT_CID: MBEDTLS_SSL_DEBUG_MSG(3, ("found CID extension")); ret = ssl_parse_cid_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */ #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC: MBEDTLS_SSL_DEBUG_MSG(3, ("found encrypt then mac extension")); ret = ssl_parse_encrypt_then_mac_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) case MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET: MBEDTLS_SSL_DEBUG_MSG(3, ("found extended master secret extension")); ret = ssl_parse_extended_ms_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) case MBEDTLS_TLS_EXT_SESSION_TICKET: MBEDTLS_SSL_DEBUG_MSG(3, ("found session ticket extension")); ret = ssl_parse_session_ticket_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_SSL_SESSION_TICKETS */ #if defined(MBEDTLS_SSL_ALPN) case MBEDTLS_TLS_EXT_ALPN: MBEDTLS_SSL_DEBUG_MSG(3, ("found alpn extension")); ret = ssl_parse_alpn_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_SSL_SESSION_TICKETS */ #if defined(MBEDTLS_SSL_DTLS_SRTP) case MBEDTLS_TLS_EXT_USE_SRTP: MBEDTLS_SSL_DEBUG_MSG(3, ("found use_srtp extension")); ret = ssl_parse_use_srtp_ext(ssl, ext + 4, ext_size); if (ret != 0) { return ret; } break; #endif /* MBEDTLS_SSL_DTLS_SRTP */ default: MBEDTLS_SSL_DEBUG_MSG(3, ("unknown extension found: %u (ignoring)", ext_id)); } ext_len -= 4 + ext_size; ext += 4 + ext_size; } #if defined(MBEDTLS_SSL_PROTO_SSL3) } #endif #if defined(MBEDTLS_SSL_FALLBACK_SCSV) for (i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2) { if (MBEDTLS_GET_UINT16_BE(p, 0) == MBEDTLS_SSL_FALLBACK_SCSV_VALUE) { MBEDTLS_SSL_DEBUG_MSG(2, ("received FALLBACK_SCSV")); if (ssl->minor_ver < ssl->conf->max_minor_ver) { MBEDTLS_SSL_DEBUG_MSG(1, ("inapropriate fallback")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } break; } } #endif /* MBEDTLS_SSL_FALLBACK_SCSV */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) /* * Try to fall back to default hash SHA1 if the client * hasn't provided any preferred signature-hash combinations. */ if (sig_hash_alg_ext_present == 0) { mbedtls_md_type_t md_default = MBEDTLS_MD_SHA1; if (mbedtls_ssl_check_sig_hash(ssl, md_default) != 0) { md_default = MBEDTLS_MD_NONE; } mbedtls_ssl_sig_hash_set_const_hash(&ssl->handshake->hash_algs, md_default); } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 && MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */ /* * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */ for (i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2) { if (p[0] == 0 && p[1] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO) { MBEDTLS_SSL_DEBUG_MSG(3, ("received TLS_EMPTY_RENEGOTIATION_INFO ")); #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS) { MBEDTLS_SSL_DEBUG_MSG(1, ("received RENEGOTIATION SCSV " "during renegotiation")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } #endif ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION; break; } } /* * Renegotiation security checks */ if (ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION && ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE) { MBEDTLS_SSL_DEBUG_MSG(1, ("legacy renegotiation, breaking off handshake")); handshake_failure = 1; } #if defined(MBEDTLS_SSL_RENEGOTIATION) else if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && ssl->secure_renegotiation == MBEDTLS_SSL_SECURE_RENEGOTIATION && renegotiation_info_seen == 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("renegotiation_info extension missing (secure)")); handshake_failure = 1; } else if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION && ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION) { MBEDTLS_SSL_DEBUG_MSG(1, ("legacy renegotiation not allowed")); handshake_failure = 1; } else if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION && renegotiation_info_seen == 1) { MBEDTLS_SSL_DEBUG_MSG(1, ("renegotiation_info extension present (legacy)")); handshake_failure = 1; } #endif /* MBEDTLS_SSL_RENEGOTIATION */ if (handshake_failure == 1) { mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO; } /* * Search for a matching ciphersuite * (At the end because we need information from the EC-based extensions * and certificate from the SNI callback triggered by the SNI extension.) */ got_common_suite = 0; ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver]; ciphersuite_info = NULL; #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE) for (j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2) { for (i = 0; ciphersuites[i] != 0; i++) { if (MBEDTLS_GET_UINT16_BE(p, 0) != ciphersuites[i]) { continue; } got_common_suite = 1; if ((ret = ssl_ciphersuite_match(ssl, ciphersuites[i], &ciphersuite_info)) != 0) { return ret; } if (ciphersuite_info != NULL) { goto have_ciphersuite; } } } #else for (i = 0; ciphersuites[i] != 0; i++) { for (j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2) { if (MBEDTLS_GET_UINT16_BE(p, 0) != ciphersuites[i]) { continue; } got_common_suite = 1; if ((ret = ssl_ciphersuite_match(ssl, ciphersuites[i], &ciphersuite_info)) != 0) { return ret; } if (ciphersuite_info != NULL) { goto have_ciphersuite; } } } #endif if (got_common_suite) { MBEDTLS_SSL_DEBUG_MSG(1, ("got ciphersuites in common, " "but none of them usable")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE; } else { MBEDTLS_SSL_DEBUG_MSG(1, ("got no ciphersuites in common")); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE); return MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN; } have_ciphersuite: MBEDTLS_SSL_DEBUG_MSG(2, ("selected ciphersuite: %s", ciphersuite_info->name)); ssl->session_negotiate->ciphersuite = ciphersuites[i]; ssl->handshake->ciphersuite_info = ciphersuite_info; ssl->state++; #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) { mbedtls_ssl_recv_flight_completed(ssl); } #endif /* Debugging-only output for testsuite */ #if defined(MBEDTLS_DEBUG_C) && \ defined(MBEDTLS_SSL_PROTO_TLS1_2) && \ defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) if (ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3) { mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_alg(ciphersuite_info); if (sig_alg != MBEDTLS_PK_NONE) { mbedtls_md_type_t md_alg = mbedtls_ssl_sig_hash_set_find(&ssl->handshake->hash_algs, sig_alg); MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, signature_algorithm ext: %d", mbedtls_ssl_hash_from_md_alg(md_alg))); } else { MBEDTLS_SSL_DEBUG_MSG(3, ("no hash algorithm for signature algorithm " "%u - should not happen", (unsigned) sig_alg)); } } #endif MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse client hello")); return 0; } #if defined(MBEDTLS_SSL_TRUNCATED_HMAC) static void ssl_write_truncated_hmac_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { unsigned char *p = buf; if (ssl->session_negotiate->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding truncated hmac extension")); MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_TRUNCATED_HMAC, p, 0); p += 2; *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */ #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) static void ssl_write_cid_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { unsigned char *p = buf; size_t ext_len; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN; *olen = 0; /* Skip writing the extension if we don't want to use it or if * the client hasn't offered it. */ if (ssl->handshake->cid_in_use == MBEDTLS_SSL_CID_DISABLED) { return; } /* ssl->own_cid_len is at most MBEDTLS_SSL_CID_IN_LEN_MAX * which is at most 255, so the increment cannot overflow. */ if (end < p || (size_t) (end - p) < (unsigned) (ssl->own_cid_len + 5)) { MBEDTLS_SSL_DEBUG_MSG(1, ("buffer too small")); return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding CID extension")); /* * Quoting draft-ietf-tls-dtls-connection-id-05 * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05 * * struct { * opaque cid<0..2^8-1>; * } ConnectionId; */ MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_CID, p, 0); p += 2; ext_len = (size_t) ssl->own_cid_len + 1; MBEDTLS_PUT_UINT16_BE(ext_len, p, 0); p += 2; *p++ = (uint8_t) ssl->own_cid_len; memcpy(p, ssl->own_cid, ssl->own_cid_len); *olen = ssl->own_cid_len + 5; } #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) static void ssl_write_encrypt_then_mac_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { unsigned char *p = buf; const mbedtls_ssl_ciphersuite_t *suite = NULL; const mbedtls_cipher_info_t *cipher = NULL; if (ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0) { ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_DISABLED; } /* * RFC 7366: "If a server receives an encrypt-then-MAC request extension * from a client and then selects a stream or Authenticated Encryption * with Associated Data (AEAD) ciphersuite, it MUST NOT send an * encrypt-then-MAC response extension back to the client." */ if ((suite = mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite)) == NULL || (cipher = mbedtls_cipher_info_from_type(suite->cipher)) == NULL || cipher->mode != MBEDTLS_MODE_CBC) { ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_DISABLED; } if (ssl->session_negotiate->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding encrypt then mac extension")); MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC, p, 0); p += 2; *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) static void ssl_write_extended_ms_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { unsigned char *p = buf; if (ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED || ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding extended master secret " "extension")); MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET, p, 0); p += 2; *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) static void ssl_write_session_ticket_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { unsigned char *p = buf; if (ssl->handshake->new_session_ticket == 0) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding session ticket extension")); MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_SESSION_TICKET, p, 0); p += 2; *p++ = 0x00; *p++ = 0x00; *olen = 4; } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ static void ssl_write_renegotiation_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { unsigned char *p = buf; if (ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, secure renegotiation extension")); MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_RENEGOTIATION_INFO, p, 0); p += 2; #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) { *p++ = 0x00; *p++ = (ssl->verify_data_len * 2 + 1) & 0xFF; *p++ = ssl->verify_data_len * 2 & 0xFF; memcpy(p, ssl->peer_verify_data, ssl->verify_data_len); p += ssl->verify_data_len; memcpy(p, ssl->own_verify_data, ssl->verify_data_len); p += ssl->verify_data_len; } else #endif /* MBEDTLS_SSL_RENEGOTIATION */ { *p++ = 0x00; *p++ = 0x01; *p++ = 0x00; } *olen = p - buf; } #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) static void ssl_write_max_fragment_length_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { unsigned char *p = buf; if (ssl->session_negotiate->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, max_fragment_length extension")); MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH, p, 0); p += 2; *p++ = 0x00; *p++ = 1; *p++ = ssl->session_negotiate->mfl_code; *olen = 5; } #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */ #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \ defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) static void ssl_write_supported_point_formats_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { unsigned char *p = buf; ((void) ssl); if ((ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT) == 0) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, supported_point_formats extension")); MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS, p, 0); p += 2; *p++ = 0x00; *p++ = 2; *p++ = 1; *p++ = MBEDTLS_ECP_PF_UNCOMPRESSED; *olen = 6; } #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) static void ssl_write_ecjpake_kkpp_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; unsigned char *p = buf; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN; size_t kkpp_len; *olen = 0; /* Skip costly computation if not needed */ if (ssl->handshake->ciphersuite_info->key_exchange != MBEDTLS_KEY_EXCHANGE_ECJPAKE) { return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, ecjpake kkpp extension")); if (end - p < 4) { MBEDTLS_SSL_DEBUG_MSG(1, ("buffer too small")); return; } MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_ECJPAKE_KKPP, p, 0); p += 2; ret = mbedtls_ecjpake_write_round_one(&ssl->handshake->ecjpake_ctx, p + 2, end - p - 2, &kkpp_len, ssl->conf->f_rng, ssl->conf->p_rng); if (ret != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_write_round_one", ret); return; } MBEDTLS_PUT_UINT16_BE(kkpp_len, p, 0); p += 2; *olen = kkpp_len + 4; } #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ #if defined(MBEDTLS_SSL_ALPN) static void ssl_write_alpn_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { if (ssl->alpn_chosen == NULL) { *olen = 0; return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding alpn extension")); /* * 0 . 1 ext identifier * 2 . 3 ext length * 4 . 5 protocol list length * 6 . 6 protocol name length * 7 . 7+n protocol name */ MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_ALPN, buf, 0); *olen = 7 + strlen(ssl->alpn_chosen); MBEDTLS_PUT_UINT16_BE(*olen - 4, buf, 2); MBEDTLS_PUT_UINT16_BE(*olen - 6, buf, 4); buf[6] = MBEDTLS_BYTE_0(*olen - 7); memcpy(buf + 7, ssl->alpn_chosen, *olen - 7); } #endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */ #if defined(MBEDTLS_SSL_DTLS_SRTP) && defined(MBEDTLS_SSL_PROTO_DTLS) static void ssl_write_use_srtp_ext(mbedtls_ssl_context *ssl, unsigned char *buf, size_t *olen) { size_t mki_len = 0, ext_len = 0; uint16_t profile_value = 0; const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN; *olen = 0; if ((ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM) || (ssl->dtls_srtp_info.chosen_dtls_srtp_profile == MBEDTLS_TLS_SRTP_UNSET)) { return; } MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding use_srtp extension")); if (ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED) { mki_len = ssl->dtls_srtp_info.mki_len; } /* The extension total size is 9 bytes : * - 2 bytes for the extension tag * - 2 bytes for the total size * - 2 bytes for the protection profile length * - 2 bytes for the protection profile * - 1 byte for the mki length * + the actual mki length * Check we have enough room in the output buffer */ if ((size_t) (end - buf) < mki_len + 9) { MBEDTLS_SSL_DEBUG_MSG(1, ("buffer too small")); return; } /* extension */ MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_USE_SRTP, buf, 0); /* * total length 5 and mki value: only one profile(2 bytes) * and length(2 bytes) and srtp_mki ) */ ext_len = 5 + mki_len; MBEDTLS_PUT_UINT16_BE(ext_len, buf, 2); /* protection profile length: 2 */ buf[4] = 0x00; buf[5] = 0x02; profile_value = mbedtls_ssl_check_srtp_profile_value( ssl->dtls_srtp_info.chosen_dtls_srtp_profile); if (profile_value != MBEDTLS_TLS_SRTP_UNSET) { MBEDTLS_PUT_UINT16_BE(profile_value, buf, 6); } else { MBEDTLS_SSL_DEBUG_MSG(1, ("use_srtp extension invalid profile")); return; } buf[8] = mki_len & 0xFF; memcpy(&buf[9], ssl->dtls_srtp_info.mki_value, mki_len); *olen = 9 + mki_len; } #endif /* MBEDTLS_SSL_DTLS_SRTP */ #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_write_hello_verify_request(mbedtls_ssl_context *ssl) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; unsigned char *p = ssl->out_msg + 4; unsigned char *cookie_len_byte; MBEDTLS_SSL_DEBUG_MSG(2, ("=> write hello verify request")); /* * struct { * ProtocolVersion server_version; * opaque cookie<0..2^8-1>; * } HelloVerifyRequest; */ /* The RFC is not clear on this point, but sending the actual negotiated * version looks like the most interoperable thing to do. */ mbedtls_ssl_write_version(ssl->major_ver, ssl->minor_ver, ssl->conf->transport, p); MBEDTLS_SSL_DEBUG_BUF(3, "server version", p, 2); p += 2; /* If we get here, f_cookie_check is not null */ if (ssl->conf->f_cookie_write == NULL) { MBEDTLS_SSL_DEBUG_MSG(1, ("inconsistent cookie callbacks")); return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } /* Skip length byte until we know the length */ cookie_len_byte = p++; if ((ret = ssl->conf->f_cookie_write(ssl->conf->p_cookie, &p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN, ssl->cli_id, ssl->cli_id_len)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "f_cookie_write", ret); return ret; } *cookie_len_byte = (unsigned char) (p - (cookie_len_byte + 1)); MBEDTLS_SSL_DEBUG_BUF(3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte); ssl->out_msglen = p - ssl->out_msg; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST; ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT; if ((ret = mbedtls_ssl_write_handshake_msg(ssl)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_write_handshake_msg", ret); return ret; } #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && (ret = mbedtls_ssl_flight_transmit(ssl)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_flight_transmit", ret); return ret; } #endif /* MBEDTLS_SSL_PROTO_DTLS */ MBEDTLS_SSL_DEBUG_MSG(2, ("<= write hello verify request")); return 0; } #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */ static void ssl_handle_id_based_session_resumption(mbedtls_ssl_context *ssl) { int ret; mbedtls_ssl_session session_tmp; mbedtls_ssl_session * const session = ssl->session_negotiate; /* Resume is 0 by default, see ssl_handshake_init(). * It may be already set to 1 by ssl_parse_session_ticket_ext(). */ if (ssl->handshake->resume == 1) { return; } if (session->id_len == 0) { return; } if (ssl->conf->f_get_cache == NULL) { return; } #if defined(MBEDTLS_SSL_RENEGOTIATION) if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) { return; } #endif mbedtls_ssl_session_init(&session_tmp); session_tmp.id_len = session->id_len; memcpy(session_tmp.id, session->id, session->id_len); ret = ssl->conf->f_get_cache(ssl->conf->p_cache, &session_tmp); if (ret != 0) { goto exit; } if (session->ciphersuite != session_tmp.ciphersuite || session->compression != session_tmp.compression) { /* Mismatch between cached and negotiated session */ goto exit; } /* Move semantics */ mbedtls_ssl_session_free(session); *session = session_tmp; memset(&session_tmp, 0, sizeof(session_tmp)); MBEDTLS_SSL_DEBUG_MSG(3, ("session successfully restored from cache")); ssl->handshake->resume = 1; exit: mbedtls_ssl_session_free(&session_tmp); } MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_write_server_hello(mbedtls_ssl_context *ssl) { #if defined(MBEDTLS_HAVE_TIME) mbedtls_time_t t; #endif int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t olen, ext_len = 0, n; unsigned char *buf, *p; MBEDTLS_SSL_DEBUG_MSG(2, ("=> write server hello")); #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ssl->handshake->verify_cookie_len != 0) { MBEDTLS_SSL_DEBUG_MSG(2, ("client hello was not authenticated")); MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server hello")); return ssl_write_hello_verify_request(ssl); } #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */ if (ssl->conf->f_rng == NULL) { MBEDTLS_SSL_DEBUG_MSG(1, ("no RNG provided")); return MBEDTLS_ERR_SSL_NO_RNG; } /* * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 5 protocol version * 6 . 9 UNIX time() * 10 . 37 random bytes */ buf = ssl->out_msg; p = buf + 4; mbedtls_ssl_write_version(ssl->major_ver, ssl->minor_ver, ssl->conf->transport, p); p += 2; MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, chosen version: [%d:%d]", buf[4], buf[5])); #if defined(MBEDTLS_HAVE_TIME) t = mbedtls_time(NULL); MBEDTLS_PUT_UINT32_BE(t, p, 0); p += 4; MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, current time: %" MBEDTLS_PRINTF_LONGLONG, (long long) t)); #else if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, p, 4)) != 0) { return ret; } p += 4; #endif /* MBEDTLS_HAVE_TIME */ if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, p, 28)) != 0) { return ret; } p += 28; memcpy(ssl->handshake->randbytes + 32, buf + 6, 32); MBEDTLS_SSL_DEBUG_BUF(3, "server hello, random bytes", buf + 6, 32); ssl_handle_id_based_session_resumption(ssl); if (ssl->handshake->resume == 0) { /* * New session, create a new session id, * unless we're about to issue a session ticket */ ssl->state++; #if defined(MBEDTLS_HAVE_TIME) ssl->session_negotiate->start = mbedtls_time(NULL); #endif #if defined(MBEDTLS_SSL_SESSION_TICKETS) if (ssl->handshake->new_session_ticket != 0) { ssl->session_negotiate->id_len = n = 0; memset(ssl->session_negotiate->id, 0, 32); } else #endif /* MBEDTLS_SSL_SESSION_TICKETS */ { ssl->session_negotiate->id_len = n = 32; if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, ssl->session_negotiate->id, n)) != 0) { return ret; } } } else { /* * Resuming a session */ n = ssl->session_negotiate->id_len; ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC; if ((ret = mbedtls_ssl_derive_keys(ssl)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_derive_keys", ret); return ret; } } /* * 38 . 38 session id length * 39 . 38+n session id * 39+n . 40+n chosen ciphersuite * 41+n . 41+n chosen compression alg. * 42+n . 43+n extensions length * 44+n . 43+n+m extensions */ *p++ = (unsigned char) ssl->session_negotiate->id_len; memcpy(p, ssl->session_negotiate->id, ssl->session_negotiate->id_len); p += ssl->session_negotiate->id_len; MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, session id len.: %" MBEDTLS_PRINTF_SIZET, n)); MBEDTLS_SSL_DEBUG_BUF(3, "server hello, session id", buf + 39, n); MBEDTLS_SSL_DEBUG_MSG(3, ("%s session has been resumed", ssl->handshake->resume ? "a" : "no")); MBEDTLS_PUT_UINT16_BE(ssl->session_negotiate->ciphersuite, p, 0); p += 2; *p++ = MBEDTLS_BYTE_0(ssl->session_negotiate->compression); MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, chosen ciphersuite: %s", mbedtls_ssl_get_ciphersuite_name(ssl->session_negotiate->ciphersuite))); MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, compress alg.: 0x%02X", (unsigned int) ssl->session_negotiate->compression)); /* Do not write the extensions if the protocol is SSLv3 */ #if defined(MBEDTLS_SSL_PROTO_SSL3) if ((ssl->major_ver != 3) || (ssl->minor_ver != 0)) { #endif /* * First write extensions, then the total length */ ssl_write_renegotiation_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) ssl_write_max_fragment_length_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #endif #if defined(MBEDTLS_SSL_TRUNCATED_HMAC) ssl_write_truncated_hmac_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #endif #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) ssl_write_cid_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #endif #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) ssl_write_encrypt_then_mac_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #endif #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) ssl_write_extended_ms_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #endif #if defined(MBEDTLS_SSL_SESSION_TICKETS) ssl_write_session_ticket_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #endif #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \ defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) if (mbedtls_ssl_ciphersuite_uses_ec( mbedtls_ssl_ciphersuite_from_id(ssl->session_negotiate->ciphersuite))) { ssl_write_supported_point_formats_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; } #endif #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) ssl_write_ecjpake_kkpp_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #endif #if defined(MBEDTLS_SSL_ALPN) ssl_write_alpn_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #endif #if defined(MBEDTLS_SSL_DTLS_SRTP) ssl_write_use_srtp_ext(ssl, p + 2 + ext_len, &olen); ext_len += olen; #endif MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, total extension length: %" MBEDTLS_PRINTF_SIZET, ext_len)); if (ext_len > 0) { MBEDTLS_PUT_UINT16_BE(ext_len, p, 0); p += 2 + ext_len; } #if defined(MBEDTLS_SSL_PROTO_SSL3) } #endif ssl->out_msglen = p - buf; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO; ret = mbedtls_ssl_write_handshake_msg(ssl); MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server hello")); return ret; } #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_write_certificate_request(mbedtls_ssl_context *ssl) { const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate request")); if (!mbedtls_ssl_ciphersuite_cert_req_allowed(ciphersuite_info)) { MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip write certificate request")); ssl->state++; return 0; } MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_write_certificate_request(mbedtls_ssl_context *ssl) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; uint16_t dn_size, total_dn_size; /* excluding length bytes */ size_t ct_len, sa_len; /* including length bytes */ unsigned char *buf, *p; const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN; const mbedtls_x509_crt *crt; int authmode; MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate request")); ssl->state++; #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 (!mbedtls_ssl_ciphersuite_cert_req_allowed(ciphersuite_info) || authmode == MBEDTLS_SSL_VERIFY_NONE) { MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip write certificate request")); return 0; } /* * 0 . 0 handshake type * 1 . 3 handshake length * 4 . 4 cert type count * 5 .. m-1 cert types * m .. m+1 sig alg length (TLS 1.2 only) * m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only) * n .. n+1 length of all DNs * n+2 .. n+3 length of DN 1 * n+4 .. ... Distinguished Name #1 * ... .. ... length of DN 2, etc. */ buf = ssl->out_msg; p = buf + 4; /* * Supported certificate types * * ClientCertificateType certificate_types<1..2^8-1>; * enum { (255) } ClientCertificateType; */ ct_len = 0; #if defined(MBEDTLS_RSA_C) p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN; #endif #if defined(MBEDTLS_ECDSA_C) p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN; #endif p[0] = (unsigned char) ct_len++; p += ct_len; sa_len = 0; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) /* * Add signature_algorithms for verify (TLS 1.2) * * SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>; * * struct { * HashAlgorithm hash; * SignatureAlgorithm signature; * } SignatureAndHashAlgorithm; * * enum { (255) } HashAlgorithm; * enum { (255) } SignatureAlgorithm; */ if (ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3) { const int *cur; /* * Supported signature algorithms */ for (cur = ssl->conf->sig_hashes; *cur != MBEDTLS_MD_NONE; cur++) { unsigned char hash = mbedtls_ssl_hash_from_md_alg(*cur); if (MBEDTLS_SSL_HASH_NONE == hash || mbedtls_ssl_set_calc_verify_md(ssl, hash)) { continue; } #if defined(MBEDTLS_RSA_C) p[2 + sa_len++] = hash; p[2 + sa_len++] = MBEDTLS_SSL_SIG_RSA; #endif #if defined(MBEDTLS_ECDSA_C) p[2 + sa_len++] = hash; p[2 + sa_len++] = MBEDTLS_SSL_SIG_ECDSA; #endif } MBEDTLS_PUT_UINT16_BE(sa_len, p, 0); sa_len += 2; p += sa_len; } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ /* * DistinguishedName certificate_authorities<0..2^16-1>; * opaque DistinguishedName<1..2^16-1>; */ p += 2; total_dn_size = 0; if (ssl->conf->cert_req_ca_list == MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED) { /* NOTE: If trusted certificates are provisioned * via a CA callback (configured through * `mbedtls_ssl_conf_ca_cb()`, then the * CertificateRequest is currently left empty. */ #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) if (ssl->handshake->sni_ca_chain != NULL) { crt = ssl->handshake->sni_ca_chain; } else #endif crt = ssl->conf->ca_chain; while (crt != NULL && crt->version != 0) { /* It follows from RFC 5280 A.1 that this length * can be represented in at most 11 bits. */ dn_size = (uint16_t) crt->subject_raw.len; if (end < p || (size_t) (end - p) < 2 + (size_t) dn_size) { MBEDTLS_SSL_DEBUG_MSG(1, ("skipping CAs: buffer too short")); break; } MBEDTLS_PUT_UINT16_BE(dn_size, p, 0); p += 2; memcpy(p, crt->subject_raw.p, dn_size); p += dn_size; MBEDTLS_SSL_DEBUG_BUF(3, "requested DN", p - dn_size, dn_size); total_dn_size += 2 + dn_size; crt = crt->next; } } ssl->out_msglen = p - buf; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST; MBEDTLS_PUT_UINT16_BE(total_dn_size, ssl->out_msg, 4 + ct_len + sa_len); ret = mbedtls_ssl_write_handshake_msg(ssl); MBEDTLS_SSL_DEBUG_MSG(2, ("<= write certificate request")); return ret; } #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_get_ecdh_params_from_cert(mbedtls_ssl_context *ssl) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; mbedtls_pk_context *own_key = mbedtls_ssl_own_key(ssl); /* Check if the key is a transparent ECDH key. * This also ensures that it is safe to call mbedtls_pk_ec(). */ if (mbedtls_pk_get_type(own_key) != MBEDTLS_PK_ECKEY && mbedtls_pk_get_type(own_key) != MBEDTLS_PK_ECKEY_DH) { MBEDTLS_SSL_DEBUG_MSG(1, ("server key not ECDH capable")); return MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH; } if ((ret = mbedtls_ecdh_get_params(&ssl->handshake->ecdh_ctx, mbedtls_pk_ec(*own_key), MBEDTLS_ECDH_OURS)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, ("mbedtls_ecdh_get_params"), ret); return ret; } return 0; } #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \ defined(MBEDTLS_SSL_ASYNC_PRIVATE) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_resume_server_key_exchange(mbedtls_ssl_context *ssl, size_t *signature_len) { /* Append the signature to ssl->out_msg, leaving 2 bytes for the * signature length which will be added in ssl_write_server_key_exchange * after the call to ssl_prepare_server_key_exchange. * ssl_write_server_key_exchange also takes care of incrementing * ssl->out_msglen. */ unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2; size_t sig_max_len = (ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN - sig_start); int ret = ssl->conf->f_async_resume(ssl, sig_start, signature_len, sig_max_len); if (ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) { ssl->handshake->async_in_progress = 0; mbedtls_ssl_set_async_operation_data(ssl, NULL); } MBEDTLS_SSL_DEBUG_RET(2, "ssl_resume_server_key_exchange", ret); return ret; } #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && defined(MBEDTLS_SSL_ASYNC_PRIVATE) */ /* Prepare the ServerKeyExchange message, up to and including * calculating the signature if any, but excluding formatting the * signature and sending the message. */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_prepare_server_key_exchange(mbedtls_ssl_context *ssl, size_t *signature_len) { const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED) #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) unsigned char *dig_signed = NULL; #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */ #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED */ (void) ciphersuite_info; /* unused in some configurations */ #if !defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) (void) signature_len; #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */ ssl->out_msglen = 4; /* header (type:1, length:3) to be written later */ /* * * Part 1: Provide key exchange parameters for chosen ciphersuite. * */ /* * - ECJPAKE key exchanges */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t len = 0; ret = mbedtls_ecjpake_write_round_two( &ssl->handshake->ecjpake_ctx, ssl->out_msg + ssl->out_msglen, MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len, ssl->conf->f_rng, ssl->conf->p_rng); if (ret != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_write_round_two", ret); return ret; } ssl->out_msglen += len; } #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ /* * For (EC)DHE key exchanges with PSK, parameters are prefixed by support * identity hint (RFC 4279, Sec. 3). Until someone needs this feature, * we use empty support identity hints here. **/ #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK) { ssl->out_msg[ssl->out_msglen++] = 0x00; ssl->out_msg[ssl->out_msglen++] = 0x00; } #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */ /* * - DHE key exchanges */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED) if (mbedtls_ssl_ciphersuite_uses_dhe(ciphersuite_info)) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t len = 0; if (ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL) { MBEDTLS_SSL_DEBUG_MSG(1, ("no DH parameters set")); return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; } /* * Ephemeral DH parameters: * * struct { * opaque dh_p<1..2^16-1>; * opaque dh_g<1..2^16-1>; * opaque dh_Ys<1..2^16-1>; * } ServerDHParams; */ if ((ret = mbedtls_dhm_set_group(&ssl->handshake->dhm_ctx, &ssl->conf->dhm_P, &ssl->conf->dhm_G)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_set_group", ret); return ret; } if ((ret = mbedtls_dhm_make_params( &ssl->handshake->dhm_ctx, (int) mbedtls_mpi_size(&ssl->handshake->dhm_ctx.P), ssl->out_msg + ssl->out_msglen, &len, ssl->conf->f_rng, ssl->conf->p_rng)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_make_params", ret); return ret; } #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) dig_signed = ssl->out_msg + ssl->out_msglen; #endif ssl->out_msglen += len; MBEDTLS_SSL_DEBUG_MPI(3, "DHM: X ", &ssl->handshake->dhm_ctx.X); MBEDTLS_SSL_DEBUG_MPI(3, "DHM: P ", &ssl->handshake->dhm_ctx.P); MBEDTLS_SSL_DEBUG_MPI(3, "DHM: G ", &ssl->handshake->dhm_ctx.G); MBEDTLS_SSL_DEBUG_MPI(3, "DHM: GX", &ssl->handshake->dhm_ctx.GX); } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED */ /* * - ECDHE key exchanges */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED) if (mbedtls_ssl_ciphersuite_uses_ecdhe(ciphersuite_info)) { /* * Ephemeral ECDH parameters: * * struct { * ECParameters curve_params; * ECPoint public; * } ServerECDHParams; */ const mbedtls_ecp_curve_info **curve = NULL; const mbedtls_ecp_group_id *gid; int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t len = 0; /* Match our preference list against the offered curves */ for (gid = ssl->conf->curve_list; *gid != MBEDTLS_ECP_DP_NONE; gid++) { for (curve = ssl->handshake->curves; *curve != NULL; curve++) { if ((*curve)->grp_id == *gid) { goto curve_matching_done; } } } curve_matching_done: if (curve == NULL || *curve == NULL) { MBEDTLS_SSL_DEBUG_MSG(1, ("no matching curve for ECDHE")); return MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN; } MBEDTLS_SSL_DEBUG_MSG(2, ("ECDHE curve: %s", (*curve)->name)); if ((ret = mbedtls_ecdh_setup(&ssl->handshake->ecdh_ctx, (*curve)->grp_id)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecp_group_load", ret); return ret; } if ((ret = mbedtls_ecdh_make_params( &ssl->handshake->ecdh_ctx, &len, ssl->out_msg + ssl->out_msglen, MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, ssl->conf->f_rng, ssl->conf->p_rng)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_make_params", ret); return ret; } #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) dig_signed = ssl->out_msg + ssl->out_msglen; #endif ssl->out_msglen += len; MBEDTLS_SSL_DEBUG_ECDH(3, &ssl->handshake->ecdh_ctx, MBEDTLS_DEBUG_ECDH_Q); } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED */ /* * * Part 2: For key exchanges involving the server signing the * exchange parameters, compute and add the signature here. * */ #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) if (mbedtls_ssl_ciphersuite_uses_server_signature(ciphersuite_info)) { size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed; size_t hashlen = 0; #if defined(MBEDTLS_USE_PSA_CRYPTO) unsigned char hash[PSA_HASH_MAX_SIZE]; #else unsigned char hash[MBEDTLS_MD_MAX_SIZE]; #endif int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; /* * 2.1: Choose hash algorithm: * A: For TLS 1.2, obey signature-hash-algorithm extension * to choose appropriate hash. * B: For SSL3, TLS1.0, TLS1.1 and ECDHE_ECDSA, use SHA1 * (RFC 4492, Sec. 5.4) * C: Otherwise, use MD5 + SHA1 (RFC 4346, Sec. 7.4.3) */ mbedtls_md_type_t md_alg; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_pk_alg(ciphersuite_info); if (ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3) { /* A: For TLS 1.2, obey signature-hash-algorithm extension * (RFC 5246, Sec. 7.4.1.4.1). */ if (sig_alg == MBEDTLS_PK_NONE || (md_alg = mbedtls_ssl_sig_hash_set_find(&ssl->handshake->hash_algs, sig_alg)) == MBEDTLS_MD_NONE) { MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); /* (... because we choose a cipher suite * only if there is a matching hash.) */ return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } } else #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_1) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA) { /* B: Default hash SHA1 */ md_alg = MBEDTLS_MD_SHA1; } else #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \ MBEDTLS_SSL_PROTO_TLS1_1 */ { /* C: MD5 + SHA1 */ md_alg = MBEDTLS_MD_NONE; } MBEDTLS_SSL_DEBUG_MSG(3, ("pick hash algorithm %u for signing", (unsigned) md_alg)); /* * 2.2: Compute the hash to be signed */ #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_1) if (md_alg == MBEDTLS_MD_NONE) { hashlen = 36; ret = mbedtls_ssl_get_key_exchange_md_ssl_tls(ssl, hash, dig_signed, dig_signed_len); if (ret != 0) { return ret; } } else #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \ MBEDTLS_SSL_PROTO_TLS1_1 */ #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_2) if (md_alg != MBEDTLS_MD_NONE) { ret = mbedtls_ssl_get_key_exchange_md_tls1_2(ssl, hash, &hashlen, dig_signed, dig_signed_len, md_alg); if (ret != 0) { return ret; } } else #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \ MBEDTLS_SSL_PROTO_TLS1_2 */ { MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } MBEDTLS_SSL_DEBUG_BUF(3, "parameters hash", hash, hashlen); /* * 2.3: Compute and add the signature */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) if (ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3) { /* * For TLS 1.2, we need to specify signature and hash algorithm * explicitly through a prefix to the signature. * * struct { * HashAlgorithm hash; * SignatureAlgorithm signature; * } SignatureAndHashAlgorithm; * * struct { * SignatureAndHashAlgorithm algorithm; * opaque signature<0..2^16-1>; * } DigitallySigned; * */ ssl->out_msg[ssl->out_msglen++] = mbedtls_ssl_hash_from_md_alg(md_alg); ssl->out_msg[ssl->out_msglen++] = mbedtls_ssl_sig_from_pk_alg(sig_alg); } #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) if (ssl->conf->f_async_sign_start != NULL) { ret = ssl->conf->f_async_sign_start(ssl, mbedtls_ssl_own_cert(ssl), md_alg, hash, hashlen); switch (ret) { case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH: /* act as if f_async_sign was null */ break; case 0: ssl->handshake->async_in_progress = 1; return ssl_resume_server_key_exchange(ssl, signature_len); case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS: ssl->handshake->async_in_progress = 1; return MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS; default: MBEDTLS_SSL_DEBUG_RET(1, "f_async_sign_start", ret); return ret; } } #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ if (mbedtls_ssl_own_key(ssl) == NULL) { MBEDTLS_SSL_DEBUG_MSG(1, ("got no private key")); return MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED; } /* Append the signature to ssl->out_msg, leaving 2 bytes for the * signature length which will be added in ssl_write_server_key_exchange * after the call to ssl_prepare_server_key_exchange. * ssl_write_server_key_exchange also takes care of incrementing * ssl->out_msglen. */ if ((ret = mbedtls_pk_sign(mbedtls_ssl_own_key(ssl), md_alg, hash, hashlen, ssl->out_msg + ssl->out_msglen + 2, signature_len, ssl->conf->f_rng, ssl->conf->p_rng)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_pk_sign", ret); return ret; } } #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */ return 0; } /* Prepare the ServerKeyExchange message and send it. For ciphersuites * that do not include a ServerKeyExchange message, do nothing. Either * way, if successful, move on to the next step in the SSL state * machine. */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_write_server_key_exchange(mbedtls_ssl_context *ssl) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t signature_len = 0; #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED) const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */ MBEDTLS_SSL_DEBUG_MSG(2, ("=> write server key exchange")); #if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED) /* Extract static ECDH parameters and abort if ServerKeyExchange * is not needed. */ if (mbedtls_ssl_ciphersuite_no_pfs(ciphersuite_info)) { /* For suites involving ECDH, extract DH parameters * from certificate at this point. */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED) if (mbedtls_ssl_ciphersuite_uses_ecdh(ciphersuite_info)) { ret = ssl_get_ecdh_params_from_cert(ssl); if (ret != 0) { MBEDTLS_SSL_DEBUG_RET(1, "ssl_get_ecdh_params_from_cert", ret); return ret; } } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED */ /* Key exchanges not involving ephemeral keys don't use * ServerKeyExchange, so end here. */ MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip write server key exchange")); ssl->state++; return 0; } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \ defined(MBEDTLS_SSL_ASYNC_PRIVATE) /* If we have already prepared the message and there is an ongoing * signature operation, resume signing. */ if (ssl->handshake->async_in_progress != 0) { MBEDTLS_SSL_DEBUG_MSG(2, ("resuming signature operation")); ret = ssl_resume_server_key_exchange(ssl, &signature_len); } else #endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && defined(MBEDTLS_SSL_ASYNC_PRIVATE) */ { /* ServerKeyExchange is needed. Prepare the message. */ ret = ssl_prepare_server_key_exchange(ssl, &signature_len); } if (ret != 0) { /* If we're starting to write a new message, set ssl->out_msglen * to 0. But if we're resuming after an asynchronous message, * out_msglen is the amount of data written so far and mst be * preserved. */ if (ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) { MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server key exchange (pending)")); } else { ssl->out_msglen = 0; } return ret; } /* If there is a signature, write its length. * ssl_prepare_server_key_exchange already wrote the signature * itself at its proper place in the output buffer. */ #if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) if (signature_len != 0) { ssl->out_msg[ssl->out_msglen++] = MBEDTLS_BYTE_1(signature_len); ssl->out_msg[ssl->out_msglen++] = MBEDTLS_BYTE_0(signature_len); MBEDTLS_SSL_DEBUG_BUF(3, "my signature", ssl->out_msg + ssl->out_msglen, signature_len); /* Skip over the already-written signature */ ssl->out_msglen += signature_len; } #endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */ /* Add header and send. */ ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE; ssl->state++; if ((ret = mbedtls_ssl_write_handshake_msg(ssl)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_write_handshake_msg", ret); return ret; } MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server key exchange")); return 0; } MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_write_server_hello_done(mbedtls_ssl_context *ssl) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; MBEDTLS_SSL_DEBUG_MSG(2, ("=> write server hello done")); ssl->out_msglen = 4; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO_DONE; ssl->state++; #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) { mbedtls_ssl_send_flight_completed(ssl); } #endif if ((ret = mbedtls_ssl_write_handshake_msg(ssl)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_write_handshake_msg", ret); return ret; } #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && (ret = mbedtls_ssl_flight_transmit(ssl)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_flight_transmit", ret); return ret; } #endif /* MBEDTLS_SSL_PROTO_DTLS */ MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server hello done")); return 0; } #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_client_dh_public(mbedtls_ssl_context *ssl, unsigned char **p, const unsigned char *end) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; size_t n; /* * Receive G^Y mod P, premaster = (G^Y)^X mod P */ if (*p + 2 > end) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } n = ((*p)[0] << 8) | (*p)[1]; *p += 2; if (*p + n > end) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } if ((ret = mbedtls_dhm_read_public(&ssl->handshake->dhm_ctx, *p, n)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_read_public", ret); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP; } *p += n; MBEDTLS_SSL_DEBUG_MPI(3, "DHM: GY", &ssl->handshake->dhm_ctx.GY); return ret; } #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_resume_decrypt_pms(mbedtls_ssl_context *ssl, unsigned char *peer_pms, size_t *peer_pmslen, size_t peer_pmssize) { int ret = ssl->conf->f_async_resume(ssl, peer_pms, peer_pmslen, peer_pmssize); if (ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) { ssl->handshake->async_in_progress = 0; mbedtls_ssl_set_async_operation_data(ssl, NULL); } MBEDTLS_SSL_DEBUG_RET(2, "ssl_decrypt_encrypted_pms", ret); return ret; } #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_decrypt_encrypted_pms(mbedtls_ssl_context *ssl, const unsigned char *p, const unsigned char *end, unsigned char *peer_pms, size_t *peer_pmslen, size_t peer_pmssize) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; mbedtls_x509_crt *own_cert = mbedtls_ssl_own_cert(ssl); if (own_cert == NULL) { MBEDTLS_SSL_DEBUG_MSG(1, ("got no local certificate")); return MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE; } mbedtls_pk_context *public_key = &own_cert->pk; mbedtls_pk_context *private_key = mbedtls_ssl_own_key(ssl); size_t len = mbedtls_pk_get_len(public_key); #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) /* If we have already started decoding the message and there is an ongoing * decryption operation, resume signing. */ if (ssl->handshake->async_in_progress != 0) { MBEDTLS_SSL_DEBUG_MSG(2, ("resuming decryption operation")); return ssl_resume_decrypt_pms(ssl, peer_pms, peer_pmslen, peer_pmssize); } #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ /* * Prepare to decrypt the premaster using own private RSA key */ #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_2) if (ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0) { if (p + 2 > end) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } if (*p++ != MBEDTLS_BYTE_1(len) || *p++ != MBEDTLS_BYTE_0(len)) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } } #endif if (p + len != end) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } /* * Decrypt the premaster secret */ #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) if (ssl->conf->f_async_decrypt_start != NULL) { ret = ssl->conf->f_async_decrypt_start(ssl, mbedtls_ssl_own_cert(ssl), p, len); switch (ret) { case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH: /* act as if f_async_decrypt_start was null */ break; case 0: ssl->handshake->async_in_progress = 1; return ssl_resume_decrypt_pms(ssl, peer_pms, peer_pmslen, peer_pmssize); case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS: ssl->handshake->async_in_progress = 1; return MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS; default: MBEDTLS_SSL_DEBUG_RET(1, "f_async_decrypt_start", ret); return ret; } } #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ if (!mbedtls_pk_can_do(private_key, MBEDTLS_PK_RSA)) { MBEDTLS_SSL_DEBUG_MSG(1, ("got no RSA private key")); return MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED; } ret = mbedtls_pk_decrypt(private_key, p, len, peer_pms, peer_pmslen, peer_pmssize, ssl->conf->f_rng, ssl->conf->p_rng); return ret; } MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_encrypted_pms(mbedtls_ssl_context *ssl, const unsigned char *p, const unsigned char *end, size_t pms_offset) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; unsigned char *pms = ssl->handshake->premaster + pms_offset; unsigned char ver[2]; unsigned char fake_pms[48], peer_pms[48]; unsigned char mask; size_t i, peer_pmslen; unsigned int diff; /* In case of a failure in decryption, the decryption may write less than * 2 bytes of output, but we always read the first two bytes. It doesn't * matter in the end because diff will be nonzero in that case due to * ret being nonzero, and we only care whether diff is 0. * But do initialize peer_pms and peer_pmslen for robustness anyway. This * also makes memory analyzers happy (don't access uninitialized memory, * even if it's an unsigned char). */ peer_pms[0] = peer_pms[1] = ~0; peer_pmslen = 0; ret = ssl_decrypt_encrypted_pms(ssl, p, end, peer_pms, &peer_pmslen, sizeof(peer_pms)); #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) if (ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) { return ret; } #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ mbedtls_ssl_write_version(ssl->handshake->max_major_ver, ssl->handshake->max_minor_ver, ssl->conf->transport, ver); /* Avoid data-dependent branches while checking for invalid * padding, to protect against timing-based Bleichenbacher-type * attacks. */ diff = (unsigned int) ret; diff |= peer_pmslen ^ 48; diff |= peer_pms[0] ^ ver[0]; diff |= peer_pms[1] ^ ver[1]; /* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */ mask = mbedtls_ct_uint_mask(diff); /* * Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding * must not cause the connection to end immediately; instead, send a * bad_record_mac later in the handshake. * To protect against timing-based variants of the attack, we must * not have any branch that depends on whether the decryption was * successful. In particular, always generate the fake premaster secret, * regardless of whether it will ultimately influence the output or not. */ ret = ssl->conf->f_rng(ssl->conf->p_rng, fake_pms, sizeof(fake_pms)); if (ret != 0) { /* It's ok to abort on an RNG failure, since this does not reveal * anything about the RSA decryption. */ return ret; } #if defined(MBEDTLS_SSL_DEBUG_ALL) if (diff != 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); } #endif if (sizeof(ssl->handshake->premaster) < pms_offset || sizeof(ssl->handshake->premaster) - pms_offset < 48) { MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } ssl->handshake->pmslen = 48; /* Set pms to either the true or the fake PMS, without * data-dependent branches. */ for (i = 0; i < ssl->handshake->pmslen; i++) { pms[i] = (mask & fake_pms[i]) | ((~mask) & peer_pms[i]); } return 0; } #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_client_psk_identity(mbedtls_ssl_context *ssl, unsigned char **p, const unsigned char *end) { int ret = 0; uint16_t n; if (ssl_conf_has_psk_or_cb(ssl->conf) == 0) { MBEDTLS_SSL_DEBUG_MSG(1, ("got no pre-shared key")); return MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED; } /* * Receive client pre-shared key identity name */ if (end - *p < 2) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } n = ((*p)[0] << 8) | (*p)[1]; *p += 2; if (n == 0 || n > end - *p) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } if (ssl->conf->f_psk != NULL) { if (ssl->conf->f_psk(ssl->conf->p_psk, ssl, *p, n) != 0) { ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY; } } else { /* Identity is not a big secret since clients send it in the clear, * but treat it carefully anyway, just in case */ if (n != ssl->conf->psk_identity_len || mbedtls_ct_memcmp(ssl->conf->psk_identity, *p, n) != 0) { ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY; } } if (ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY) { MBEDTLS_SSL_DEBUG_BUF(3, "Unknown PSK identity", *p, n); mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY); return MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY; } *p += n; return 0; } #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_client_key_exchange(mbedtls_ssl_context *ssl) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; const mbedtls_ssl_ciphersuite_t *ciphersuite_info; unsigned char *p, *end; ciphersuite_info = ssl->handshake->ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse client key exchange")); #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) && \ (defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)) if ((ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA) && (ssl->handshake->async_in_progress != 0)) { /* We've already read a record and there is an asynchronous * operation in progress to decrypt it. So skip reading the * record. */ MBEDTLS_SSL_DEBUG_MSG(3, ("will resume decryption of previously-read record")); } else #endif if ((ret = mbedtls_ssl_read_record(ssl, 1)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_read_record", ret); return ret; } p = ssl->in_msg + mbedtls_ssl_hs_hdr_len(ssl); end = ssl->in_msg + ssl->in_hslen; if (ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } if (ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA) { if ((ret = ssl_parse_client_dh_public(ssl, &p, end)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_dh_public"), ret); return ret; } if (p != end) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } if ((ret = mbedtls_dhm_calc_secret(&ssl->handshake->dhm_ctx, ssl->handshake->premaster, MBEDTLS_PREMASTER_SIZE, &ssl->handshake->pmslen, ssl->conf->f_rng, ssl->conf->p_rng)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_calc_secret", ret); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS; } MBEDTLS_SSL_DEBUG_MPI(3, "DHM: K ", &ssl->handshake->dhm_ctx.K); } else #endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \ defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA || ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA) { if ((ret = mbedtls_ecdh_read_public(&ssl->handshake->ecdh_ctx, p, end - p)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_read_public", ret); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP; } MBEDTLS_SSL_DEBUG_ECDH(3, &ssl->handshake->ecdh_ctx, MBEDTLS_DEBUG_ECDH_QP); if ((ret = mbedtls_ecdh_calc_secret(&ssl->handshake->ecdh_ctx, &ssl->handshake->pmslen, ssl->handshake->premaster, MBEDTLS_MPI_MAX_SIZE, ssl->conf->f_rng, ssl->conf->p_rng)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_calc_secret", ret); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS; } MBEDTLS_SSL_DEBUG_ECDH(3, &ssl->handshake->ecdh_ctx, MBEDTLS_DEBUG_ECDH_Z); } else #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED || MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK) { if ((ret = ssl_parse_client_psk_identity(ssl, &p, end)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_psk_identity"), ret); return ret; } if (p != end) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } #if defined(MBEDTLS_USE_PSA_CRYPTO) /* For opaque PSKs, we perform the PSK-to-MS derivation automatically * and skip the intermediate PMS. */ if (ssl_use_opaque_psk(ssl) == 1) { MBEDTLS_SSL_DEBUG_MSG(1, ("skip PMS generation for opaque PSK")); } else #endif /* MBEDTLS_USE_PSA_CRYPTO */ if ((ret = mbedtls_ssl_psk_derive_premaster(ssl, ciphersuite_info->key_exchange)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_psk_derive_premaster", ret); return ret; } } else #endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK) { #if defined(MBEDTLS_SSL_ASYNC_PRIVATE) if (ssl->handshake->async_in_progress != 0) { /* There is an asynchronous operation in progress to * decrypt the encrypted premaster secret, so skip * directly to resuming this operation. */ MBEDTLS_SSL_DEBUG_MSG(3, ("PSK identity already parsed")); /* Update p to skip the PSK identity. ssl_parse_encrypted_pms * won't actually use it, but maintain p anyway for robustness. */ p += ssl->conf->psk_identity_len + 2; } else #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */ if ((ret = ssl_parse_client_psk_identity(ssl, &p, end)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_psk_identity"), ret); return ret; } #if defined(MBEDTLS_USE_PSA_CRYPTO) /* Opaque PSKs are currently only supported for PSK-only. */ if (ssl_use_opaque_psk(ssl) == 1) { MBEDTLS_SSL_DEBUG_MSG(1, ("opaque PSK not supported with RSA-PSK")); return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; } #endif if ((ret = ssl_parse_encrypted_pms(ssl, p, end, 2)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_encrypted_pms"), ret); return ret; } if ((ret = mbedtls_ssl_psk_derive_premaster(ssl, ciphersuite_info->key_exchange)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_psk_derive_premaster", ret); return ret; } } else #endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK) { if ((ret = ssl_parse_client_psk_identity(ssl, &p, end)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_psk_identity"), ret); return ret; } if ((ret = ssl_parse_client_dh_public(ssl, &p, end)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_dh_public"), ret); return ret; } #if defined(MBEDTLS_USE_PSA_CRYPTO) /* Opaque PSKs are currently only supported for PSK-only. */ if (ssl_use_opaque_psk(ssl) == 1) { MBEDTLS_SSL_DEBUG_MSG(1, ("opaque PSK not supported with DHE-PSK")); return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; } #endif if (p != end) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange")); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE; } if ((ret = mbedtls_ssl_psk_derive_premaster(ssl, ciphersuite_info->key_exchange)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_psk_derive_premaster", ret); return ret; } } else #endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK) { if ((ret = ssl_parse_client_psk_identity(ssl, &p, end)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_psk_identity"), ret); return ret; } if ((ret = mbedtls_ecdh_read_public(&ssl->handshake->ecdh_ctx, p, end - p)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_read_public", ret); return MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP; } #if defined(MBEDTLS_USE_PSA_CRYPTO) /* Opaque PSKs are currently only supported for PSK-only. */ if (ssl_use_opaque_psk(ssl) == 1) { MBEDTLS_SSL_DEBUG_MSG(1, ("opaque PSK not supported with ECDHE-PSK")); return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; } #endif MBEDTLS_SSL_DEBUG_ECDH(3, &ssl->handshake->ecdh_ctx, MBEDTLS_DEBUG_ECDH_QP); if ((ret = mbedtls_ssl_psk_derive_premaster(ssl, ciphersuite_info->key_exchange)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_psk_derive_premaster", ret); return ret; } } else #endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA) { if ((ret = ssl_parse_encrypted_pms(ssl, p, end, 0)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_parse_encrypted_pms_secret"), ret); return ret; } } else #endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */ #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE) { ret = mbedtls_ecjpake_read_round_two(&ssl->handshake->ecjpake_ctx, p, end - p); if (ret != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_read_round_two", ret); return MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE; } ret = mbedtls_ecjpake_derive_secret(&ssl->handshake->ecjpake_ctx, ssl->handshake->premaster, 32, &ssl->handshake->pmslen, ssl->conf->f_rng, ssl->conf->p_rng); if (ret != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_derive_secret", ret); return ret; } } else #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */ { MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } if ((ret = mbedtls_ssl_derive_keys(ssl)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_derive_keys", ret); return ret; } ssl->state++; MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse client key exchange")); return 0; } #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_certificate_verify(mbedtls_ssl_context *ssl) { const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse certificate verify")); if (!mbedtls_ssl_ciphersuite_cert_req_allowed(ciphersuite_info)) { MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip parse certificate verify")); ssl->state++; return 0; } MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */ MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_parse_certificate_verify(mbedtls_ssl_context *ssl) { int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; size_t i, sig_len; unsigned char hash[48]; unsigned char *hash_start = hash; size_t hashlen; #if defined(MBEDTLS_SSL_PROTO_TLS1_2) mbedtls_pk_type_t pk_alg; #endif mbedtls_md_type_t md_alg; const mbedtls_ssl_ciphersuite_t *ciphersuite_info = ssl->handshake->ciphersuite_info; mbedtls_pk_context *peer_pk; MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse certificate verify")); if (!mbedtls_ssl_ciphersuite_cert_req_allowed(ciphersuite_info)) { MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip parse certificate verify")); ssl->state++; return 0; } #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) if (ssl->session_negotiate->peer_cert == NULL) { MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip parse certificate verify")); ssl->state++; return 0; } #else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ if (ssl->session_negotiate->peer_cert_digest == NULL) { MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip parse certificate verify")); ssl->state++; return 0; } #endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ /* Read the message without adding it to the checksum */ ret = mbedtls_ssl_read_record(ssl, 0 /* no checksum update */); if (0 != ret) { MBEDTLS_SSL_DEBUG_RET(1, ("mbedtls_ssl_read_record"), ret); return ret; } ssl->state++; /* Process the message contents */ if (ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE || ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE_VERIFY) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate verify message")); return MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY; } i = mbedtls_ssl_hs_hdr_len(ssl); #if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) peer_pk = &ssl->handshake->peer_pubkey; #else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ if (ssl->session_negotiate->peer_cert == NULL) { /* Should never happen */ return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } peer_pk = &ssl->session_negotiate->peer_cert->pk; #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ /* * struct { * SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only * opaque signature<0..2^16-1>; * } DigitallySigned; */ #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \ defined(MBEDTLS_SSL_PROTO_TLS1_1) if (ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_3) { md_alg = MBEDTLS_MD_NONE; hashlen = 36; /* For ECDSA, use SHA-1, not MD-5 + SHA-1 */ if (mbedtls_pk_can_do(peer_pk, MBEDTLS_PK_ECDSA)) { hash_start += 16; hashlen -= 16; md_alg = MBEDTLS_MD_SHA1; } } else #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 */ #if defined(MBEDTLS_SSL_PROTO_TLS1_2) if (ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3) { if (i + 2 > ssl->in_hslen) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate verify message")); return MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY; } /* * Hash */ md_alg = mbedtls_ssl_md_alg_from_hash(ssl->in_msg[i]); if (md_alg == MBEDTLS_MD_NONE || mbedtls_ssl_set_calc_verify_md(ssl, ssl->in_msg[i])) { MBEDTLS_SSL_DEBUG_MSG(1, ("peer not adhering to requested sig_alg" " for verify message")); return MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY; } #if !defined(MBEDTLS_MD_SHA1) if (MBEDTLS_MD_SHA1 == md_alg) { hash_start += 16; } #endif /* Info from md_alg will be used instead */ hashlen = 0; i++; /* * Signature */ if ((pk_alg = mbedtls_ssl_pk_alg_from_sig(ssl->in_msg[i])) == MBEDTLS_PK_NONE) { MBEDTLS_SSL_DEBUG_MSG(1, ("peer not adhering to requested sig_alg" " for verify message")); return MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY; } /* * Check the certificate's key type matches the signature alg */ if (!mbedtls_pk_can_do(peer_pk, pk_alg)) { MBEDTLS_SSL_DEBUG_MSG(1, ("sig_alg doesn't match cert key")); return MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY; } i++; } else #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ { MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen")); return MBEDTLS_ERR_SSL_INTERNAL_ERROR; } if (i + 2 > ssl->in_hslen) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate verify message")); return MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY; } sig_len = (ssl->in_msg[i] << 8) | ssl->in_msg[i+1]; i += 2; if (i + sig_len != ssl->in_hslen) { MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate verify message")); return MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY; } /* Calculate hash and verify signature */ { size_t dummy_hlen; ssl->handshake->calc_verify(ssl, hash, &dummy_hlen); } if ((ret = mbedtls_pk_verify(peer_pk, md_alg, hash_start, hashlen, ssl->in_msg + i, sig_len)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_pk_verify", ret); return ret; } mbedtls_ssl_update_handshake_status(ssl); MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse certificate verify")); return ret; } #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */ #if defined(MBEDTLS_SSL_SESSION_TICKETS) MBEDTLS_CHECK_RETURN_CRITICAL static int ssl_write_new_session_ticket(mbedtls_ssl_context *ssl) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t tlen; uint32_t lifetime; MBEDTLS_SSL_DEBUG_MSG(2, ("=> write new session ticket")); ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msg[0] = MBEDTLS_SSL_HS_NEW_SESSION_TICKET; /* * struct { * uint32 ticket_lifetime_hint; * opaque ticket<0..2^16-1>; * } NewSessionTicket; * * 4 . 7 ticket_lifetime_hint (0 = unspecified) * 8 . 9 ticket_len (n) * 10 . 9+n ticket content */ if ((ret = ssl->conf->f_ticket_write(ssl->conf->p_ticket, ssl->session_negotiate, ssl->out_msg + 10, ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN, &tlen, &lifetime)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_ticket_write", ret); tlen = 0; } MBEDTLS_PUT_UINT32_BE(lifetime, ssl->out_msg, 4); MBEDTLS_PUT_UINT16_BE(tlen, ssl->out_msg, 8); ssl->out_msglen = 10 + tlen; /* * Morally equivalent to updating ssl->state, but NewSessionTicket and * ChangeCipherSpec share the same state. */ ssl->handshake->new_session_ticket = 0; if ((ret = mbedtls_ssl_write_handshake_msg(ssl)) != 0) { MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_write_handshake_msg", ret); return ret; } MBEDTLS_SSL_DEBUG_MSG(2, ("<= write new session ticket")); return 0; } #endif /* MBEDTLS_SSL_SESSION_TICKETS */ /* * SSL handshake -- server side -- single step */ int mbedtls_ssl_handshake_server_step(mbedtls_ssl_context *ssl) { int ret = 0; if (ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL) { return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; } MBEDTLS_SSL_DEBUG_MSG(2, ("server state: %d", ssl->state)); if ((ret = mbedtls_ssl_flush_output(ssl)) != 0) { return ret; } #if defined(MBEDTLS_SSL_PROTO_DTLS) if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING) { if ((ret = mbedtls_ssl_flight_transmit(ssl)) != 0) { return ret; } } #endif /* MBEDTLS_SSL_PROTO_DTLS */ switch (ssl->state) { case MBEDTLS_SSL_HELLO_REQUEST: ssl->state = MBEDTLS_SSL_CLIENT_HELLO; break; /* * <== ClientHello */ case MBEDTLS_SSL_CLIENT_HELLO: ret = ssl_parse_client_hello(ssl); break; #if defined(MBEDTLS_SSL_PROTO_DTLS) case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT: return MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED; #endif /* * ==> ServerHello * Certificate * ( ServerKeyExchange ) * ( CertificateRequest ) * ServerHelloDone */ case MBEDTLS_SSL_SERVER_HELLO: ret = ssl_write_server_hello(ssl); break; case MBEDTLS_SSL_SERVER_CERTIFICATE: ret = mbedtls_ssl_write_certificate(ssl); break; case MBEDTLS_SSL_SERVER_KEY_EXCHANGE: ret = ssl_write_server_key_exchange(ssl); break; case MBEDTLS_SSL_CERTIFICATE_REQUEST: ret = ssl_write_certificate_request(ssl); break; case MBEDTLS_SSL_SERVER_HELLO_DONE: ret = ssl_write_server_hello_done(ssl); break; /* * <== ( Certificate/Alert ) * ClientKeyExchange * ( CertificateVerify ) * ChangeCipherSpec * Finished */ case MBEDTLS_SSL_CLIENT_CERTIFICATE: ret = mbedtls_ssl_parse_certificate(ssl); break; case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE: ret = ssl_parse_client_key_exchange(ssl); break; case MBEDTLS_SSL_CERTIFICATE_VERIFY: ret = ssl_parse_certificate_verify(ssl); break; case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC: ret = mbedtls_ssl_parse_change_cipher_spec(ssl); break; case MBEDTLS_SSL_CLIENT_FINISHED: ret = mbedtls_ssl_parse_finished(ssl); break; /* * ==> ( NewSessionTicket ) * ChangeCipherSpec * Finished */ case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC: #if defined(MBEDTLS_SSL_SESSION_TICKETS) if (ssl->handshake->new_session_ticket != 0) { ret = ssl_write_new_session_ticket(ssl); } else #endif ret = mbedtls_ssl_write_change_cipher_spec(ssl); break; case MBEDTLS_SSL_SERVER_FINISHED: ret = mbedtls_ssl_write_finished(ssl); break; case MBEDTLS_SSL_FLUSH_BUFFERS: MBEDTLS_SSL_DEBUG_MSG(2, ("handshake: done")); ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP; break; case MBEDTLS_SSL_HANDSHAKE_WRAPUP: mbedtls_ssl_handshake_wrapup(ssl); break; default: MBEDTLS_SSL_DEBUG_MSG(1, ("invalid state %d", ssl->state)); return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; } return ret; } #endif /* MBEDTLS_SSL_SRV_C */