| /* |
| * Copyright 2005-2025 The OpenSSL Project Authors. All Rights Reserved. |
| * |
| * Licensed under the Apache License 2.0 (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 "internal/e_os.h" |
| #include "internal/e_winsock.h" /* struct timeval for DTLS_CTRL_GET_TIMEOUT */ |
| #include <stdio.h> |
| #include <openssl/objects.h> |
| #include <openssl/rand.h> |
| #include "ssl_local.h" |
| #include "internal/time.h" |
| #include "internal/ssl_unwrap.h" |
| |
| static int dtls1_handshake_write(SSL_CONNECTION *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_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, |
| dtls1_set_handshake_header, |
| dtls1_close_construct_packet, |
| dtls1_handshake_write |
| }; |
| |
| const SSL3_ENC_METHOD DTLSv1_2_enc_data = { |
| 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_SIGALGS |
| | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS, |
| dtls1_set_handshake_header, |
| dtls1_close_construct_packet, |
| dtls1_handshake_write |
| }; |
| |
| OSSL_TIME 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 ossl_seconds2time(60 * 60 * 2); |
| } |
| |
| int dtls1_new(SSL *ssl) |
| { |
| DTLS1_STATE *d1; |
| SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl); |
| |
| if (s == NULL) |
| return 0; |
| |
| if (!DTLS_RECORD_LAYER_new(&s->rlayer)) { |
| return 0; |
| } |
| |
| if (!ssl3_new(ssl)) |
| return 0; |
| if ((d1 = OPENSSL_zalloc(sizeof(*d1))) == NULL) { |
| ssl3_free(ssl); |
| 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(ssl); |
| return 0; |
| } |
| |
| s->d1 = d1; |
| |
| if (!ssl->method->ssl_clear(ssl)) |
| return 0; |
| |
| return 1; |
| } |
| |
| static void dtls1_clear_queues(SSL_CONNECTION *s) |
| { |
| dtls1_clear_received_buffer(s); |
| dtls1_clear_sent_buffer(s); |
| } |
| |
| void dtls1_clear_received_buffer(SSL_CONNECTION *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_CONNECTION *s) |
| { |
| pitem *item = NULL; |
| hm_fragment *frag = NULL; |
| |
| while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) { |
| frag = (hm_fragment *)item->data; |
| |
| if (frag->msg_header.is_ccs |
| && frag->msg_header.saved_retransmit_state.wrlmethod != NULL |
| && s->rlayer.wrl != frag->msg_header.saved_retransmit_state.wrl) { |
| /* |
| * If we're freeing the CCS then we're done with the old wrl and it |
| * can bee freed |
| */ |
| frag->msg_header.saved_retransmit_state.wrlmethod->free(frag->msg_header.saved_retransmit_state.wrl); |
| } |
| |
| dtls1_hm_fragment_free(frag); |
| pitem_free(item); |
| } |
| } |
| |
| |
| void dtls1_free(SSL *ssl) |
| { |
| SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl); |
| |
| if (s == NULL) |
| return; |
| |
| if (s->d1 != NULL) { |
| dtls1_clear_queues(s); |
| pqueue_free(s->d1->buffered_messages); |
| pqueue_free(s->d1->sent_messages); |
| } |
| |
| DTLS_RECORD_LAYER_free(&s->rlayer); |
| |
| ssl3_free(ssl); |
| |
| OPENSSL_free(s->d1); |
| s->d1 = NULL; |
| } |
| |
| int dtls1_clear(SSL *ssl) |
| { |
| pqueue *buffered_messages; |
| pqueue *sent_messages; |
| size_t mtu; |
| size_t link_mtu; |
| |
| SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl); |
| |
| if (s == NULL) |
| return 0; |
| |
| 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(ssl) & 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(ssl)) |
| return 0; |
| |
| if (ssl->method->version == DTLS_ANY_VERSION) |
| s->version = DTLS_MAX_VERSION_INTERNAL; |
| #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 = ssl->method->version; |
| |
| return 1; |
| } |
| |
| long dtls1_ctrl(SSL *ssl, int cmd, long larg, void *parg) |
| { |
| int ret = 0; |
| OSSL_TIME t; |
| SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl); |
| |
| if (s == NULL) |
| return 0; |
| |
| switch (cmd) { |
| case DTLS_CTRL_GET_TIMEOUT: |
| if (dtls1_get_timeout(s, &t)) { |
| *(struct timeval *)parg = ossl_time_to_timeval(t); |
| 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(ssl, cmd, larg, parg); |
| break; |
| } |
| return ret; |
| } |
| |
| static void dtls1_bio_set_next_timeout(BIO *bio, const DTLS1_STATE *d1) |
| { |
| struct timeval tv = ossl_time_to_timeval(d1->next_timeout); |
| |
| BIO_ctrl(bio, BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &tv); |
| } |
| |
| void dtls1_start_timer(SSL_CONNECTION *s) |
| { |
| OSSL_TIME duration; |
| SSL *ssl = SSL_CONNECTION_GET_SSL(s); |
| |
| #ifndef OPENSSL_NO_SCTP |
| /* Disable timer for SCTP */ |
| if (BIO_dgram_is_sctp(SSL_get_wbio(ssl))) { |
| s->d1->next_timeout = ossl_time_zero(); |
| return; |
| } |
| #endif |
| |
| /* |
| * If timer is not set, initialize duration with 1 second or |
| * a user-specified value if the timer callback is installed. |
| */ |
| if (ossl_time_is_zero(s->d1->next_timeout)) { |
| if (s->d1->timer_cb != NULL) |
| s->d1->timeout_duration_us = s->d1->timer_cb(ssl, 0); |
| else |
| s->d1->timeout_duration_us = 1000000; |
| } |
| |
| /* Set timeout to current time plus duration */ |
| duration = ossl_us2time(s->d1->timeout_duration_us); |
| s->d1->next_timeout = ossl_time_add(ossl_time_now(), duration); |
| |
| /* set s->d1->next_timeout into ssl->rbio interface */ |
| dtls1_bio_set_next_timeout(SSL_get_rbio(ssl), s->d1); |
| } |
| |
| int dtls1_get_timeout(const SSL_CONNECTION *s, OSSL_TIME *timeleft) |
| { |
| OSSL_TIME timenow; |
| |
| /* If no timeout is set, just return NULL */ |
| if (ossl_time_is_zero(s->d1->next_timeout)) |
| return 0; |
| |
| /* Get current time */ |
| timenow = ossl_time_now(); |
| |
| /* |
| * If timer already expired or if remaining time is less than 15 ms, |
| * set it to 0 to prevent issues because of small divergences with |
| * socket timeouts. |
| */ |
| *timeleft = ossl_time_subtract(s->d1->next_timeout, timenow); |
| if (ossl_time_compare(*timeleft, ossl_ms2time(15)) <= 0) |
| *timeleft = ossl_time_zero(); |
| return 1; |
| } |
| |
| int dtls1_is_timer_expired(SSL_CONNECTION *s) |
| { |
| OSSL_TIME timeleft; |
| |
| /* Get time left until timeout, return false if no timer running */ |
| if (!dtls1_get_timeout(s, &timeleft)) |
| return 0; |
| |
| /* Return false if timer is not expired yet */ |
| if (!ossl_time_is_zero(timeleft)) |
| return 0; |
| |
| /* Timer expired, so return true */ |
| return 1; |
| } |
| |
| static void dtls1_double_timeout(SSL_CONNECTION *s) |
| { |
| s->d1->timeout_duration_us *= 2; |
| if (s->d1->timeout_duration_us > 60000000) |
| s->d1->timeout_duration_us = 60000000; |
| } |
| |
| void dtls1_stop_timer(SSL_CONNECTION *s) |
| { |
| /* Reset everything */ |
| s->d1->timeout_num_alerts = 0; |
| s->d1->next_timeout = ossl_time_zero(); |
| s->d1->timeout_duration_us = 1000000; |
| dtls1_bio_set_next_timeout(s->rbio, s->d1); |
| /* Clear retransmission buffer */ |
| dtls1_clear_sent_buffer(s); |
| } |
| |
| int dtls1_check_timeout_num(SSL_CONNECTION *s) |
| { |
| size_t mtu; |
| SSL *ssl = SSL_CONNECTION_GET_SSL(s); |
| |
| s->d1->timeout_num_alerts++; |
| |
| /* Reduce MTU after 2 unsuccessful retransmissions */ |
| if (s->d1->timeout_num_alerts > 2 |
| && !(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) { |
| mtu = |
| BIO_ctrl(SSL_get_wbio(ssl), 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 */ |
| SSLfatal(s, SSL_AD_NO_ALERT, SSL_R_READ_TIMEOUT_EXPIRED); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| int dtls1_handle_timeout(SSL_CONNECTION *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(SSL_CONNECTION_GET_USER_SSL(s), |
| s->d1->timeout_duration_us); |
| else |
| dtls1_double_timeout(s); |
| |
| if (dtls1_check_timeout_num(s) < 0) { |
| /* SSLfatal() already called */ |
| return -1; |
| } |
| |
| dtls1_start_timer(s); |
| /* Calls SSLfatal() if required */ |
| return dtls1_retransmit_buffered_messages(s); |
| } |
| |
| #define LISTEN_SUCCESS 2 |
| #define LISTEN_SEND_VERIFY_REQUEST 1 |
| |
| #ifndef OPENSSL_NO_SOCK |
| int DTLSv1_listen(SSL *ssl, BIO_ADDR *client) |
| { |
| int next, n, ret = 0; |
| unsigned char cookie[DTLS1_COOKIE_LENGTH]; |
| unsigned char seq[SEQ_NUM_SIZE]; |
| const unsigned char *data; |
| unsigned char *buf = NULL, *wbuf; |
| size_t fragoff, fraglen, msglen; |
| unsigned int rectype, versmajor, versminor, msgseq, msgtype, clientvers, cookielen; |
| BIO *rbio, *wbio; |
| BIO_ADDR *tmpclient = NULL; |
| PACKET pkt, msgpkt, msgpayload, session, cookiepkt; |
| SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl); |
| |
| if (s == NULL) |
| return -1; |
| |
| if (s->handshake_func == NULL) { |
| /* Not properly initialized yet */ |
| SSL_set_accept_state(ssl); |
| } |
| |
| /* Ensure there is no state left over from a previous invocation */ |
| if (!SSL_clear(ssl)) |
| return -1; |
| |
| ERR_clear_error(); |
| |
| rbio = SSL_get_rbio(ssl); |
| wbio = SSL_get_wbio(ssl); |
| |
| if (!rbio || !wbio) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_BIO_NOT_SET); |
| return -1; |
| } |
| |
| /* |
| * 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)) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_UNSUPPORTED_SSL_VERSION); |
| return -1; |
| } |
| |
| buf = OPENSSL_malloc(DTLS1_RT_HEADER_LENGTH + SSL3_RT_MAX_PLAIN_LENGTH); |
| if (buf == NULL) |
| return -1; |
| wbuf = OPENSSL_malloc(DTLS1_RT_HEADER_LENGTH + SSL3_RT_MAX_PLAIN_LENGTH); |
| if (wbuf == NULL) { |
| OPENSSL_free(buf); |
| return -1; |
| } |
| |
| do { |
| /* Get a packet */ |
| |
| clear_sys_error(); |
| n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH |
| + DTLS1_RT_HEADER_LENGTH); |
| if (n <= 0) { |
| if (BIO_should_retry(rbio)) { |
| /* Non-blocking IO */ |
| goto end; |
| } |
| ret = -1; |
| goto end; |
| } |
| |
| if (!PACKET_buf_init(&pkt, buf, n)) { |
| ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR); |
| ret = -1; |
| goto end; |
| } |
| |
| /* |
| * 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) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_RECORD_TOO_SMALL); |
| goto end; |
| } |
| |
| /* Get the record header */ |
| if (!PACKET_get_1(&pkt, &rectype) |
| || !PACKET_get_1(&pkt, &versmajor) |
| || !PACKET_get_1(&pkt, &versminor)) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH); |
| goto end; |
| } |
| |
| if (s->msg_callback) |
| s->msg_callback(0, (versmajor << 8) | versminor, SSL3_RT_HEADER, buf, |
| DTLS1_RT_HEADER_LENGTH, ssl, s->msg_callback_arg); |
| |
| if (rectype != SSL3_RT_HANDSHAKE) { |
| ERR_raise(ERR_LIB_SSL, 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) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_BAD_PROTOCOL_VERSION_NUMBER); |
| goto end; |
| } |
| |
| /* Save the sequence number: 64 bits, with top 2 bytes = epoch */ |
| if (!PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE) |
| || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) { |
| ERR_raise(ERR_LIB_SSL, 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) { |
| ERR_raise(ERR_LIB_SSL, 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) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH); |
| goto end; |
| } |
| |
| if (msgtype != SSL3_MT_CLIENT_HELLO) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_UNEXPECTED_MESSAGE); |
| goto end; |
| } |
| |
| /* Message sequence number can only be 0 or 1 */ |
| if (msgseq > 2) { |
| ERR_raise(ERR_LIB_SSL, 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) */ |
| ERR_raise(ERR_LIB_SSL, 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, ssl, |
| s->msg_callback_arg); |
| |
| if (!PACKET_get_net_2(&msgpayload, &clientvers)) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_LENGTH_MISMATCH); |
| goto end; |
| } |
| |
| /* |
| * Verify client version is supported |
| */ |
| if (DTLS_VERSION_LT(clientvers, (unsigned int)ssl->method->version) && |
| ssl->method->version != DTLS_ANY_VERSION) { |
| ERR_raise(ERR_LIB_SSL, 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. |
| */ |
| ERR_raise(ERR_LIB_SSL, 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 (ssl->ctx->app_verify_cookie_cb == NULL) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_NO_VERIFY_COOKIE_CALLBACK); |
| /* This is fatal */ |
| ret = -1; |
| goto end; |
| } |
| if (ssl->ctx->app_verify_cookie_cb(ssl, 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. |
| */ |
| |
| /* Generate the cookie */ |
| if (ssl->ctx->app_gen_cookie_cb == NULL || |
| ssl->ctx->app_gen_cookie_cb(ssl, cookie, &cookielen) == 0 || |
| cookielen > 255) { |
| ERR_raise(ERR_LIB_SSL, SSL_R_COOKIE_GEN_CALLBACK_FAILURE); |
| /* This is fatal */ |
| ret = -1; |
| goto end; |
| } |
| |
| /* |
| * 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 = (ssl->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION |
| : s->version; |
| |
| /* Construct the record and message headers */ |
| if (!WPACKET_init_static_len(&wpkt, |
| wbuf, |
| ssl_get_max_send_fragment(s) |
| + DTLS1_RT_HEADER_LENGTH, |
| 0) |
| || !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)) { |
| ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR); |
| WPACKET_cleanup(&wpkt); |
| /* This is fatal */ |
| ret = -1; |
| goto end; |
| } |
| |
| /* |
| * 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(&wbuf[DTLS1_RT_HEADER_LENGTH + 1], |
| &wbuf[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, ssl, |
| s->msg_callback_arg); |
| |
| if ((tmpclient = BIO_ADDR_new()) == NULL) { |
| ERR_raise(ERR_LIB_SSL, ERR_R_BIO_LIB); |
| 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, wbuf, 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; |
| } |
| ret = -1; |
| goto end; |
| } |
| |
| 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; |
| } |
| ret = -1; |
| goto end; |
| } |
| } |
| } 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; |
| s->rlayer.wrlmethod->increment_sequence_ctr(s->rlayer.wrl); |
| |
| /* |
| * We are doing cookie exchange, so make sure we set that option in the |
| * SSL object |
| */ |
| SSL_set_options(ssl, 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); |
| |
| /* Buffer the record for use by the record layer */ |
| if (BIO_write(s->rlayer.rrlnext, buf, n) != n) { |
| ERR_raise(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR); |
| ret = -1; |
| goto end; |
| } |
| |
| /* |
| * Reset the record layer - but this time we can use the record we just |
| * buffered in s->rlayer.rrlnext |
| */ |
| if (!ssl_set_new_record_layer(s, |
| DTLS_ANY_VERSION, |
| OSSL_RECORD_DIRECTION_READ, |
| OSSL_RECORD_PROTECTION_LEVEL_NONE, NULL, 0, |
| NULL, 0, NULL, 0, NULL, 0, NULL, 0, |
| NID_undef, NULL, NULL, NULL)) { |
| /* SSLfatal already called */ |
| ret = -1; |
| goto end; |
| } |
| |
| ret = 1; |
| end: |
| BIO_ADDR_free(tmpclient); |
| OPENSSL_free(buf); |
| OPENSSL_free(wbuf); |
| return ret; |
| } |
| #endif |
| |
| static int dtls1_handshake_write(SSL_CONNECTION *s) |
| { |
| return dtls1_do_write(s, SSL3_RT_HANDSHAKE); |
| } |
| |
| int dtls1_shutdown(SSL *s) |
| { |
| int ret; |
| #ifndef OPENSSL_NO_SCTP |
| BIO *wbio; |
| SSL_CONNECTION *sc = SSL_CONNECTION_FROM_SSL_ONLY(s); |
| |
| if (s == NULL) |
| return -1; |
| |
| wbio = SSL_get_wbio(s); |
| if (wbio != NULL && BIO_dgram_is_sctp(wbio) && |
| !(sc->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_CONNECTION *s) |
| { |
| SSL *ssl = SSL_CONNECTION_GET_SSL(s); |
| |
| if (s->d1->link_mtu) { |
| s->d1->mtu = |
| s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(ssl)); |
| 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(ssl) & SSL_OP_NO_QUERY_MTU)) { |
| s->d1->mtu = |
| BIO_ctrl(SSL_get_wbio(ssl), 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(ssl), 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_CONNECTION *s) |
| { |
| SSL *ssl = SSL_CONNECTION_GET_SSL(s); |
| |
| return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(ssl)); |
| } |
| |
| size_t DTLS_get_data_mtu(const SSL *ssl) |
| { |
| size_t mac_overhead, int_overhead, blocksize, ext_overhead; |
| const SSL_CIPHER *ciph = SSL_get_current_cipher(ssl); |
| size_t mtu; |
| const SSL_CONNECTION *s = SSL_CONNECTION_FROM_CONST_SSL_ONLY(ssl); |
| |
| if (s == NULL) |
| return 0; |
| |
| 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 *ssl, DTLS_timer_cb cb) |
| { |
| SSL_CONNECTION *s = SSL_CONNECTION_FROM_SSL_ONLY(ssl); |
| |
| if (s == NULL) |
| return; |
| |
| s->d1->timer_cb = cb; |
| } |