/* * DTLS implementation written by Nagendra Modadugu * (nagendra@cs.stanford.edu) for the OpenSSL project 2005. */ /* ==================================================================== * Copyright (c) 1999-2005 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * openssl-core@OpenSSL.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * * This product includes cryptographic software written by Eric Young * (eay@cryptsoft.com). This product includes software written by Tim * Hudson (tjh@cryptsoft.com). * */ #include #define USE_SOCKETS #include #include #include "ssl_locl.h" #if defined(OPENSSL_SYS_VMS) # include #elif defined(OPENSSL_SYS_VXWORKS) # include #elif !defined(OPENSSL_SYS_WIN32) # include #endif static void get_current_time(struct timeval *t); static int dtls1_set_handshake_header(SSL *s, int type, unsigned long len); static int dtls1_handshake_write(SSL *s); static unsigned int dtls1_link_min_mtu(void); /* XDTLS: figure out the right values */ static const unsigned int 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, TLS1_FINISH_MAC_LENGTH, 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_HM_HEADER_LENGTH, dtls1_set_handshake_header, 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, TLS1_FINISH_MAC_LENGTH, 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_HM_HEADER_LENGTH, dtls1_set_handshake_header, 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; s->method->ssl_clear(s); return (1); } static void dtls1_clear_queues(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); } 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; } void dtls1_clear(SSL *s) { pqueue *buffered_messages; pqueue *sent_messages; unsigned int mtu; unsigned int link_mtu; DTLS_RECORD_LAYER_clear(&s->rlayer); if (s->d1) { 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)); 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; } ssl3_clear(s); if (s->options & SSL_OP_CISCO_ANYCONNECT) s->client_version = s->version = DTLS1_BAD_VER; else if (s->method->version == DTLS_ANY_VERSION) s->version = DTLS_MAX_VERSION; else s->version = s->method->version; } 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) { #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 */ if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { s->d1->timeout_duration = 1; } /* Set timeout to current time */ get_current_time(&(s->d1->next_timeout)); /* Add duration to current time */ s->d1->next_timeout.tv_sec += s->d1->timeout_duration; 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 devergences 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 *= 2; if (s->d1->timeout_duration > 60) s->d1->timeout_duration = 60; 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 = 1; BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout)); /* Clear retransmission buffer */ dtls1_clear_record_buffer(s); } int dtls1_check_timeout_num(SSL *s) { unsigned int 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; } 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; } #ifndef OPENSSL_NO_HEARTBEATS if (s->tlsext_hb_pending) { s->tlsext_hb_pending = 0; return dtls1_heartbeat(s); } #endif 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); # ifdef __MINGW32__ now.ul -= 116444736000000000ULL; # else now.ul -= 116444736000000000UI64; /* re-bias to 1/1/1970 */ # endif t->tv_sec = (long)(now.ul / 10000000); t->tv_usec = ((int)(now.ul % 10000000)) / 10; #elif defined(OPENSSL_SYS_VMS) struct timeb tb; ftime(&tb); t->tv_sec = (long)tb.time; t->tv_usec = (long)tb.millitm * 1000; #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 *p, *buf; unsigned long reclen, 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; /* 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(&msgpkt, &msglen) || !PACKET_get_net_2(&msgpkt, &msgseq) || !PACKET_get_net_3(&msgpkt, &fragoff) || !PACKET_get_net_3(&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), 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) { /* * 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; } p = &buf[DTLS1_RT_HEADER_LENGTH]; msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH, cookie, cookielen); *p++ = DTLS1_MT_HELLO_VERIFY_REQUEST; /* Message length */ l2n3(msglen, p); /* Message sequence number is always 0 for a HelloVerifyRequest */ s2n(0, p); /* * We never fragment a HelloVerifyRequest, so fragment offset is 0 * and fragment length is message length */ l2n3(0, p); l2n3(msglen, p); /* Set reclen equal to length of whole handshake message */ reclen = msglen + DTLS1_HM_HEADER_LENGTH; /* Add the record header */ p = buf; *(p++) = SSL3_RT_HANDSHAKE; /* * 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. */ if (s->method->version == DTLS_ANY_VERSION) { *(p++) = DTLS1_VERSION >> 8; *(p++) = DTLS1_VERSION & 0xff; } else { *(p++) = s->version >> 8; *(p++) = s->version & 0xff; } /* * Record sequence number is always the same as in the received * ClientHello */ memcpy(p, seq, SEQ_NUM_SIZE); p += SEQ_NUM_SIZE; /* Length */ s2n(reclen, p); /* * Set reclen equal to length of whole record including record * header */ reclen += DTLS1_RT_HEADER_LENGTH; 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; if (BIO_write(wbio, buf, reclen) < (int)reclen) { 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_set_handshake_header(SSL *s, int htype, unsigned long len) { dtls1_set_message_header(s, htype, len, 0, len); s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH; s->init_off = 0; /* Buffer the message to handle re-xmits */ if (!dtls1_buffer_message(s, 0)) return 0; return 1; } static int dtls1_handshake_write(SSL *s) { return dtls1_do_write(s, SSL3_RT_HANDSHAKE); } #ifndef OPENSSL_NO_HEARTBEATS int dtls1_process_heartbeat(SSL *s, unsigned char *p, unsigned int length) { unsigned char *pl; unsigned short hbtype; unsigned int payload; unsigned int padding = 16; /* Use minimum padding */ if (s->msg_callback) s->msg_callback(0, s->version, DTLS1_RT_HEARTBEAT, p, length, s, s->msg_callback_arg); /* Read type and payload length first */ if (1 + 2 + 16 > length) return 0; /* silently discard */ if (length > SSL3_RT_MAX_PLAIN_LENGTH) return 0; /* silently discard per RFC 6520 sec. 4 */ hbtype = *p++; n2s(p, payload); if (1 + 2 + payload + 16 > length) return 0; /* silently discard per RFC 6520 sec. 4 */ pl = p; if (hbtype == TLS1_HB_REQUEST) { unsigned char *buffer, *bp; unsigned int write_length = 1 /* heartbeat type */ + 2 /* heartbeat length */ + payload + padding; int r; if (write_length > SSL3_RT_MAX_PLAIN_LENGTH) return 0; /* * Allocate memory for the response, size is 1 byte message type, * plus 2 bytes payload length, plus payload, plus padding */ buffer = OPENSSL_malloc(write_length); if (buffer == NULL) return -1; bp = buffer; /* Enter response type, length and copy payload */ *bp++ = TLS1_HB_RESPONSE; s2n(payload, bp); memcpy(bp, pl, payload); bp += payload; /* Random padding */ if (RAND_bytes(bp, padding) <= 0) { OPENSSL_free(buffer); return -1; } r = dtls1_write_bytes(s, DTLS1_RT_HEARTBEAT, buffer, write_length); if (r >= 0 && s->msg_callback) s->msg_callback(1, s->version, DTLS1_RT_HEARTBEAT, buffer, write_length, s, s->msg_callback_arg); OPENSSL_free(buffer); if (r < 0) return r; } else if (hbtype == TLS1_HB_RESPONSE) { unsigned int seq; /* * We only send sequence numbers (2 bytes unsigned int), and 16 * random bytes, so we just try to read the sequence number */ n2s(pl, seq); if (payload == 18 && seq == s->tlsext_hb_seq) { dtls1_stop_timer(s); s->tlsext_hb_seq++; s->tlsext_hb_pending = 0; } } return 0; } int dtls1_heartbeat(SSL *s) { unsigned char *buf, *p; int ret = -1; unsigned int payload = 18; /* Sequence number + random bytes */ unsigned int padding = 16; /* Use minimum padding */ /* Only send if peer supports and accepts HB requests... */ if (!(s->tlsext_heartbeat & SSL_DTLSEXT_HB_ENABLED) || s->tlsext_heartbeat & SSL_DTLSEXT_HB_DONT_SEND_REQUESTS) { SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT); return -1; } /* ...and there is none in flight yet... */ if (s->tlsext_hb_pending) { SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING); return -1; } /* ...and no handshake in progress. */ if (SSL_in_init(s) || ossl_statem_get_in_handshake(s)) { SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE); return -1; } /*- * Create HeartBeat message, we just use a sequence number * as payload to distuingish different messages and add * some random stuff. * - Message Type, 1 byte * - Payload Length, 2 bytes (unsigned int) * - Payload, the sequence number (2 bytes uint) * - Payload, random bytes (16 bytes uint) * - Padding */ buf = OPENSSL_malloc(1 + 2 + payload + padding); if (buf == NULL) { SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_MALLOC_FAILURE); return -1; } p = buf; /* Message Type */ *p++ = TLS1_HB_REQUEST; /* Payload length (18 bytes here) */ s2n(payload, p); /* Sequence number */ s2n(s->tlsext_hb_seq, p); /* 16 random bytes */ if (RAND_bytes(p, 16) <= 0) { SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR); goto err; } p += 16; /* Random padding */ if (RAND_bytes(p, padding) <= 0) { SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR); goto err; } ret = dtls1_write_bytes(s, DTLS1_RT_HEARTBEAT, buf, 3 + payload + padding); if (ret >= 0) { if (s->msg_callback) s->msg_callback(1, s->version, DTLS1_RT_HEARTBEAT, buf, 3 + payload + padding, s, s->msg_callback_arg); dtls1_start_timer(s); s->tlsext_hb_pending = 1; } err: OPENSSL_free(buf); return ret; } #endif 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, s->d1->mtu, NULL); } } else return 0; } return 1; } static unsigned int dtls1_link_min_mtu(void) { return (g_probable_mtu[(sizeof(g_probable_mtu) / sizeof(g_probable_mtu[0])) - 1]); } unsigned int dtls1_min_mtu(SSL *s) { return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s)); }