/* * Copyright 2005-2017 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the OpenSSL license (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy * in the file LICENSE in the source distribution or at * https://www.openssl.org/source/license.html */ #include "e_os.h" #include #include #include #include "ssl_locl.h" static void get_current_time(struct timeval *t); static int dtls1_handshake_write(SSL *s); static size_t dtls1_link_min_mtu(void); /* XDTLS: figure out the right values */ static const size_t g_probable_mtu[] = { 1500, 512, 256 }; const SSL3_ENC_METHOD DTLSv1_enc_data = { tls1_enc, tls1_mac, tls1_setup_key_block, tls1_generate_master_secret, tls1_change_cipher_state, tls1_final_finish_mac, TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE, TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE, tls1_alert_code, tls1_export_keying_material, SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV, dtls1_set_handshake_header, dtls1_close_construct_packet, dtls1_handshake_write }; const SSL3_ENC_METHOD DTLSv1_2_enc_data = { tls1_enc, tls1_mac, tls1_setup_key_block, tls1_generate_master_secret, tls1_change_cipher_state, tls1_final_finish_mac, TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE, TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE, tls1_alert_code, tls1_export_keying_material, SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS, dtls1_set_handshake_header, dtls1_close_construct_packet, dtls1_handshake_write }; long dtls1_default_timeout(void) { /* * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for * http, the cache would over fill */ return (60 * 60 * 2); } int dtls1_new(SSL *s) { DTLS1_STATE *d1; if (!DTLS_RECORD_LAYER_new(&s->rlayer)) { return 0; } if (!ssl3_new(s)) return 0; if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) { ssl3_free(s); return 0; } d1->buffered_messages = pqueue_new(); d1->sent_messages = pqueue_new(); if (s->server) { d1->cookie_len = sizeof(s->d1->cookie); } d1->link_mtu = 0; d1->mtu = 0; if (d1->buffered_messages == NULL || d1->sent_messages == NULL) { pqueue_free(d1->buffered_messages); pqueue_free(d1->sent_messages); OPENSSL_free(d1); ssl3_free(s); return 0; } s->d1 = d1; if (!s->method->ssl_clear(s)) return 0; return 1; } static void dtls1_clear_queues(SSL *s) { dtls1_clear_received_buffer(s); dtls1_clear_sent_buffer(s); } void dtls1_clear_received_buffer(SSL *s) { pitem *item = NULL; hm_fragment *frag = NULL; while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) { frag = (hm_fragment *)item->data; dtls1_hm_fragment_free(frag); pitem_free(item); } } void dtls1_clear_sent_buffer(SSL *s) { pitem *item = NULL; hm_fragment *frag = NULL; while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) { frag = (hm_fragment *)item->data; dtls1_hm_fragment_free(frag); pitem_free(item); } } void dtls1_free(SSL *s) { DTLS_RECORD_LAYER_free(&s->rlayer); ssl3_free(s); dtls1_clear_queues(s); pqueue_free(s->d1->buffered_messages); pqueue_free(s->d1->sent_messages); OPENSSL_free(s->d1); s->d1 = NULL; } int dtls1_clear(SSL *s) { pqueue *buffered_messages; pqueue *sent_messages; size_t mtu; size_t link_mtu; DTLS_RECORD_LAYER_clear(&s->rlayer); if (s->d1) { DTLS_timer_cb timer_cb = s->d1->timer_cb; buffered_messages = s->d1->buffered_messages; sent_messages = s->d1->sent_messages; mtu = s->d1->mtu; link_mtu = s->d1->link_mtu; dtls1_clear_queues(s); memset(s->d1, 0, sizeof(*s->d1)); /* Restore the timer callback from previous state */ s->d1->timer_cb = timer_cb; if (s->server) { s->d1->cookie_len = sizeof(s->d1->cookie); } if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) { s->d1->mtu = mtu; s->d1->link_mtu = link_mtu; } s->d1->buffered_messages = buffered_messages; s->d1->sent_messages = sent_messages; } if (!ssl3_clear(s)) return 0; if (s->method->version == DTLS_ANY_VERSION) s->version = DTLS_MAX_VERSION; #ifndef OPENSSL_NO_DTLS1_METHOD else if (s->options & SSL_OP_CISCO_ANYCONNECT) s->client_version = s->version = DTLS1_BAD_VER; #endif else s->version = s->method->version; return 1; } long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg) { int ret = 0; switch (cmd) { case DTLS_CTRL_GET_TIMEOUT: if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) { ret = 1; } break; case DTLS_CTRL_HANDLE_TIMEOUT: ret = dtls1_handle_timeout(s); break; case DTLS_CTRL_SET_LINK_MTU: if (larg < (long)dtls1_link_min_mtu()) return 0; s->d1->link_mtu = larg; return 1; case DTLS_CTRL_GET_LINK_MIN_MTU: return (long)dtls1_link_min_mtu(); case SSL_CTRL_SET_MTU: /* * We may not have a BIO set yet so can't call dtls1_min_mtu() * We'll have to make do with dtls1_link_min_mtu() and max overhead */ if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD) return 0; s->d1->mtu = larg; return larg; default: ret = ssl3_ctrl(s, cmd, larg, parg); break; } return ret; } void dtls1_start_timer(SSL *s) { unsigned int sec, usec; #ifndef OPENSSL_NO_SCTP /* Disable timer for SCTP */ if (BIO_dgram_is_sctp(SSL_get_wbio(s))) { memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout)); return; } #endif /* * If timer is not set, initialize duration with 1 second or * a user-specified value if the timer callback is installed. */ if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { if (s->d1->timer_cb != NULL) s->d1->timeout_duration_us = s->d1->timer_cb(s, 0); else s->d1->timeout_duration_us = 1000000; } /* Set timeout to current time */ get_current_time(&(s->d1->next_timeout)); /* Add duration to current time */ sec = s->d1->timeout_duration_us / 1000000; usec = s->d1->timeout_duration_us - (sec * 1000000); s->d1->next_timeout.tv_sec += sec; s->d1->next_timeout.tv_usec += usec; if (s->d1->next_timeout.tv_usec >= 1000000) { s->d1->next_timeout.tv_sec++; s->d1->next_timeout.tv_usec -= 1000000; } BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout)); } struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft) { struct timeval timenow; /* If no timeout is set, just return NULL */ if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { return NULL; } /* Get current time */ get_current_time(&timenow); /* If timer already expired, set remaining time to 0 */ if (s->d1->next_timeout.tv_sec < timenow.tv_sec || (s->d1->next_timeout.tv_sec == timenow.tv_sec && s->d1->next_timeout.tv_usec <= timenow.tv_usec)) { memset(timeleft, 0, sizeof(*timeleft)); return timeleft; } /* Calculate time left until timer expires */ memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval)); timeleft->tv_sec -= timenow.tv_sec; timeleft->tv_usec -= timenow.tv_usec; if (timeleft->tv_usec < 0) { timeleft->tv_sec--; timeleft->tv_usec += 1000000; } /* * If remaining time is less than 15 ms, set it to 0 to prevent issues * because of small divergences with socket timeouts. */ if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) { memset(timeleft, 0, sizeof(*timeleft)); } return timeleft; } int dtls1_is_timer_expired(SSL *s) { struct timeval timeleft; /* Get time left until timeout, return false if no timer running */ if (dtls1_get_timeout(s, &timeleft) == NULL) { return 0; } /* Return false if timer is not expired yet */ if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) { return 0; } /* Timer expired, so return true */ return 1; } void dtls1_double_timeout(SSL *s) { s->d1->timeout_duration_us *= 2; if (s->d1->timeout_duration_us > 60000000) s->d1->timeout_duration_us = 60000000; dtls1_start_timer(s); } void dtls1_stop_timer(SSL *s) { /* Reset everything */ memset(&s->d1->timeout, 0, sizeof(s->d1->timeout)); memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout)); s->d1->timeout_duration_us = 1000000; BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout)); /* Clear retransmission buffer */ dtls1_clear_sent_buffer(s); } int dtls1_check_timeout_num(SSL *s) { size_t mtu; s->d1->timeout.num_alerts++; /* Reduce MTU after 2 unsuccessful retransmissions */ if (s->d1->timeout.num_alerts > 2 && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL); if (mtu < s->d1->mtu) s->d1->mtu = mtu; } if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) { /* fail the connection, enough alerts have been sent */ SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED); return -1; } return 0; } int dtls1_handle_timeout(SSL *s) { /* if no timer is expired, don't do anything */ if (!dtls1_is_timer_expired(s)) { return 0; } if (s->d1->timer_cb != NULL) s->d1->timeout_duration_us = s->d1->timer_cb(s, s->d1->timeout_duration_us); else dtls1_double_timeout(s); if (dtls1_check_timeout_num(s) < 0) return -1; s->d1->timeout.read_timeouts++; if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) { s->d1->timeout.read_timeouts = 1; } dtls1_start_timer(s); return dtls1_retransmit_buffered_messages(s); } static void get_current_time(struct timeval *t) { #if defined(_WIN32) SYSTEMTIME st; union { unsigned __int64 ul; FILETIME ft; } now; GetSystemTime(&st); SystemTimeToFileTime(&st, &now.ft); /* re-bias to 1/1/1970 */ # ifdef __MINGW32__ now.ul -= 116444736000000000ULL; # else /* *INDENT-OFF* */ now.ul -= 116444736000000000UI64; /* *INDENT-ON* */ # endif t->tv_sec = (long)(now.ul / 10000000); t->tv_usec = ((int)(now.ul % 10000000)) / 10; #else gettimeofday(t, NULL); #endif } #define LISTEN_SUCCESS 2 #define LISTEN_SEND_VERIFY_REQUEST 1 #ifndef OPENSSL_NO_SOCK int DTLSv1_listen(SSL *s, BIO_ADDR *client) { int next, n, ret = 0, clearpkt = 0; unsigned char cookie[DTLS1_COOKIE_LENGTH]; unsigned char seq[SEQ_NUM_SIZE]; const unsigned char *data; unsigned char *buf; size_t fragoff, fraglen, msglen; unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen; BIO *rbio, *wbio; BUF_MEM *bufm; BIO_ADDR *tmpclient = NULL; PACKET pkt, msgpkt, msgpayload, session, cookiepkt; if (s->handshake_func == NULL) { /* Not properly initialized yet */ SSL_set_accept_state(s); } /* Ensure there is no state left over from a previous invocation */ if (!SSL_clear(s)) return -1; ERR_clear_error(); rbio = SSL_get_rbio(s); wbio = SSL_get_wbio(s); if (!rbio || !wbio) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BIO_NOT_SET); return -1; } /* * We only peek at incoming ClientHello's until we're sure we are going to * to respond with a HelloVerifyRequest. If its a ClientHello with a valid * cookie then we leave it in the BIO for accept to handle. */ BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL); /* * Note: This check deliberately excludes DTLS1_BAD_VER because that version * requires the MAC to be calculated *including* the first ClientHello * (without the cookie). Since DTLSv1_listen is stateless that cannot be * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via * SSL_accept) */ if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION); return -1; } if (s->init_buf == NULL) { if ((bufm = BUF_MEM_new()) == NULL) { SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE); return -1; } if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) { BUF_MEM_free(bufm); SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE); return -1; } s->init_buf = bufm; } buf = (unsigned char *)s->init_buf->data; do { /* Get a packet */ clear_sys_error(); /* * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store * the record header as well, but we do here. We've set up init_buf to * be the standard size for simplicity. In practice we shouldn't ever * receive a ClientHello as long as this. If we do it will get dropped * in the record length check below. */ n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH); if (n <= 0) { if (BIO_should_retry(rbio)) { /* Non-blocking IO */ goto end; } return -1; } /* If we hit any problems we need to clear this packet from the BIO */ clearpkt = 1; if (!PACKET_buf_init(&pkt, buf, n)) { SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR); return -1; } /* * Parse the received record. If there are any problems with it we just * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is * resilient in the face of invalid records (e.g., invalid formatting, * length, MAC, etc.). In general, invalid records SHOULD be silently * discarded, thus preserving the association; however, an error MAY be * logged for diagnostic purposes." */ /* this packet contained a partial record, dump it */ if (n < DTLS1_RT_HEADER_LENGTH) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_RECORD_TOO_SMALL); goto end; } if (s->msg_callback) s->msg_callback(0, 0, SSL3_RT_HEADER, buf, DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg); /* Get the record header */ if (!PACKET_get_1(&pkt, &rectype) || !PACKET_get_1(&pkt, &versmajor)) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); goto end; } if (rectype != SSL3_RT_HANDSHAKE) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE); goto end; } /* * Check record version number. We only check that the major version is * the same. */ if (versmajor != DTLS1_VERSION_MAJOR) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER); goto end; } if (!PACKET_forward(&pkt, 1) /* Save the sequence number: 64 bits, with top 2 bytes = epoch */ || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE) || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); goto end; } /* * We allow data remaining at the end of the packet because there could * be a second record (but we ignore it) */ /* This is an initial ClientHello so the epoch has to be 0 */ if (seq[0] != 0 || seq[1] != 0) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE); goto end; } /* Get a pointer to the raw message for the later callback */ data = PACKET_data(&msgpkt); /* Finished processing the record header, now process the message */ if (!PACKET_get_1(&msgpkt, &msgtype) || !PACKET_get_net_3_len(&msgpkt, &msglen) || !PACKET_get_net_2(&msgpkt, &msgseq) || !PACKET_get_net_3_len(&msgpkt, &fragoff) || !PACKET_get_net_3_len(&msgpkt, &fraglen) || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen) || PACKET_remaining(&msgpkt) != 0) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); goto end; } if (msgtype != SSL3_MT_CLIENT_HELLO) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE); goto end; } /* Message sequence number can only be 0 or 1 */ if (msgseq > 2) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER); goto end; } /* * We don't support fragment reassembly for ClientHellos whilst * listening because that would require server side state (which is * against the whole point of the ClientHello/HelloVerifyRequest * mechanism). Instead we only look at the first ClientHello fragment * and require that the cookie must be contained within it. */ if (fragoff != 0 || fraglen > msglen) { /* Non initial ClientHello fragment (or bad fragment) */ SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO); goto end; } if (s->msg_callback) s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data, fraglen + DTLS1_HM_HEADER_LENGTH, s, s->msg_callback_arg); if (!PACKET_get_net_2(&msgpayload, &clientvers)) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); goto end; } /* * Verify client version is supported */ if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) && s->method->version != DTLS_ANY_VERSION) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_WRONG_VERSION_NUMBER); goto end; } if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE) || !PACKET_get_length_prefixed_1(&msgpayload, &session) || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) { /* * Could be malformed or the cookie does not fit within the initial * ClientHello fragment. Either way we can't handle it. */ SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH); goto end; } /* * Check if we have a cookie or not. If not we need to send a * HelloVerifyRequest. */ if (PACKET_remaining(&cookiepkt) == 0) { next = LISTEN_SEND_VERIFY_REQUEST; } else { /* * We have a cookie, so lets check it. */ if (s->ctx->app_verify_cookie_cb == NULL) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK); /* This is fatal */ return -1; } if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt), (unsigned int)PACKET_remaining(&cookiepkt)) == 0) { /* * We treat invalid cookies in the same was as no cookie as * per RFC6347 */ next = LISTEN_SEND_VERIFY_REQUEST; } else { /* Cookie verification succeeded */ next = LISTEN_SUCCESS; } } if (next == LISTEN_SEND_VERIFY_REQUEST) { WPACKET wpkt; unsigned int version; size_t wreclen; /* * There was no cookie in the ClientHello so we need to send a * HelloVerifyRequest. If this fails we do not worry about trying * to resend, we just drop it. */ /* * Dump the read packet, we don't need it any more. Ignore return * value */ BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL); BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH); BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL); /* Generate the cookie */ if (s->ctx->app_gen_cookie_cb == NULL || s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 || cookielen > 255) { SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE); /* This is fatal */ return -1; } /* * Special case: for hello verify request, client version 1.0 and we * haven't decided which version to use yet send back using version * 1.0 header: otherwise some clients will ignore it. */ version = (s->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION : s->version; /* Construct the record and message headers */ if (!WPACKET_init(&wpkt, s->init_buf) || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE) || !WPACKET_put_bytes_u16(&wpkt, version) /* * Record sequence number is always the same as in the * received ClientHello */ || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE) /* End of record, start sub packet for message */ || !WPACKET_start_sub_packet_u16(&wpkt) /* Message type */ || !WPACKET_put_bytes_u8(&wpkt, DTLS1_MT_HELLO_VERIFY_REQUEST) /* * Message length - doesn't follow normal TLS convention: * the length isn't the last thing in the message header. * We'll need to fill this in later when we know the * length. Set it to zero for now */ || !WPACKET_put_bytes_u24(&wpkt, 0) /* * Message sequence number is always 0 for a * HelloVerifyRequest */ || !WPACKET_put_bytes_u16(&wpkt, 0) /* * We never fragment a HelloVerifyRequest, so fragment * offset is 0 */ || !WPACKET_put_bytes_u24(&wpkt, 0) /* * Fragment length is the same as message length, but * this *is* the last thing in the message header so we * can just start a sub-packet. No need to come back * later for this one. */ || !WPACKET_start_sub_packet_u24(&wpkt) /* Create the actual HelloVerifyRequest body */ || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen) /* Close message body */ || !WPACKET_close(&wpkt) /* Close record body */ || !WPACKET_close(&wpkt) || !WPACKET_get_total_written(&wpkt, &wreclen) || !WPACKET_finish(&wpkt)) { SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR); WPACKET_cleanup(&wpkt); /* This is fatal */ return -1; } /* * Fix up the message len in the message header. Its the same as the * fragment len which has been filled in by WPACKET, so just copy * that. Destination for the message len is after the record header * plus one byte for the message content type. The source is the * last 3 bytes of the message header */ memcpy(&buf[DTLS1_RT_HEADER_LENGTH + 1], &buf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3], 3); if (s->msg_callback) s->msg_callback(1, 0, SSL3_RT_HEADER, buf, DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg); if ((tmpclient = BIO_ADDR_new()) == NULL) { SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE); goto end; } /* * This is unnecessary if rbio and wbio are one and the same - but * maybe they're not. We ignore errors here - some BIOs do not * support this. */ if (BIO_dgram_get_peer(rbio, tmpclient) > 0) { (void)BIO_dgram_set_peer(wbio, tmpclient); } BIO_ADDR_free(tmpclient); tmpclient = NULL; /* TODO(size_t): convert this call */ if (BIO_write(wbio, buf, wreclen) < (int)wreclen) { if (BIO_should_retry(wbio)) { /* * Non-blocking IO...but we're stateless, so we're just * going to drop this packet. */ goto end; } return -1; } if (BIO_flush(wbio) <= 0) { if (BIO_should_retry(wbio)) { /* * Non-blocking IO...but we're stateless, so we're just * going to drop this packet. */ goto end; } return -1; } } } while (next != LISTEN_SUCCESS); /* * Set expected sequence numbers to continue the handshake. */ s->d1->handshake_read_seq = 1; s->d1->handshake_write_seq = 1; s->d1->next_handshake_write_seq = 1; DTLS_RECORD_LAYER_set_write_sequence(&s->rlayer, seq); /* * We are doing cookie exchange, so make sure we set that option in the * SSL object */ SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE); /* * Tell the state machine that we've done the initial hello verify * exchange */ ossl_statem_set_hello_verify_done(s); /* * Some BIOs may not support this. If we fail we clear the client address */ if (BIO_dgram_get_peer(rbio, client) <= 0) BIO_ADDR_clear(client); ret = 1; clearpkt = 0; end: BIO_ADDR_free(tmpclient); BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL); if (clearpkt) { /* Dump this packet. Ignore return value */ BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH); } return ret; } #endif static int dtls1_handshake_write(SSL *s) { return dtls1_do_write(s, SSL3_RT_HANDSHAKE); } int dtls1_shutdown(SSL *s) { int ret; #ifndef OPENSSL_NO_SCTP BIO *wbio; wbio = SSL_get_wbio(s); if (wbio != NULL && BIO_dgram_is_sctp(wbio) && !(s->shutdown & SSL_SENT_SHUTDOWN)) { ret = BIO_dgram_sctp_wait_for_dry(wbio); if (ret < 0) return -1; if (ret == 0) BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL); } #endif ret = ssl3_shutdown(s); #ifndef OPENSSL_NO_SCTP BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL); #endif return ret; } int dtls1_query_mtu(SSL *s) { if (s->d1->link_mtu) { s->d1->mtu = s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s)); s->d1->link_mtu = 0; } /* AHA! Figure out the MTU, and stick to the right size */ if (s->d1->mtu < dtls1_min_mtu(s)) { if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); /* * I've seen the kernel return bogus numbers when it doesn't know * (initial write), so just make sure we have a reasonable number */ if (s->d1->mtu < dtls1_min_mtu(s)) { /* Set to min mtu */ s->d1->mtu = dtls1_min_mtu(s); BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, (long)s->d1->mtu, NULL); } } else return 0; } return 1; } static size_t dtls1_link_min_mtu(void) { return (g_probable_mtu[(sizeof(g_probable_mtu) / sizeof(g_probable_mtu[0])) - 1]); } size_t dtls1_min_mtu(SSL *s) { return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s)); } size_t DTLS_get_data_mtu(const SSL *s) { size_t mac_overhead, int_overhead, blocksize, ext_overhead; const SSL_CIPHER *ciph = SSL_get_current_cipher(s); size_t mtu = s->d1->mtu; if (ciph == NULL) return 0; if (!ssl_cipher_get_overhead(ciph, &mac_overhead, &int_overhead, &blocksize, &ext_overhead)) return 0; if (SSL_READ_ETM(s)) ext_overhead += mac_overhead; else int_overhead += mac_overhead; /* Subtract external overhead (e.g. IV/nonce, separate MAC) */ if (ext_overhead + DTLS1_RT_HEADER_LENGTH >= mtu) return 0; mtu -= ext_overhead + DTLS1_RT_HEADER_LENGTH; /* Round encrypted payload down to cipher block size (for CBC etc.) * No check for overflow since 'mtu % blocksize' cannot exceed mtu. */ if (blocksize) mtu -= (mtu % blocksize); /* Subtract internal overhead (e.g. CBC padding len byte) */ if (int_overhead >= mtu) return 0; mtu -= int_overhead; return mtu; } void DTLS_set_timer_cb(SSL *s, DTLS_timer_cb cb) { s->d1->timer_cb = cb; }