| // Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include <openssl/ssl.h> |
| |
| #include <assert.h> |
| #include <string.h> |
| |
| #include <algorithm> |
| |
| #include <openssl/bio.h> |
| #include <openssl/bytestring.h> |
| #include <openssl/err.h> |
| #include <openssl/evp.h> |
| #include <openssl/mem.h> |
| #include <openssl/rand.h> |
| |
| #include "../crypto/internal.h" |
| #include "internal.h" |
| |
| |
| BSSL_NAMESPACE_BEGIN |
| |
| ssl_open_record_t dtls1_process_ack(SSL *ssl, uint8_t *out_alert, |
| DTLSRecordNumber ack_record_number, |
| Span<const uint8_t> data) { |
| // As a DTLS-1.3-capable client, it is possible to receive an ACK before we |
| // receive ServerHello and learned the server picked DTLS 1.3. Thus, tolerate |
| // but ignore ACKs before the version is set. |
| if (!ssl_has_final_version(ssl)) { |
| return ssl_open_record_discard; |
| } |
| |
| // ACKs are only allowed in DTLS 1.3. Reject them if we've negotiated a |
| // version and it's not 1.3. |
| if (ssl_protocol_version(ssl) < TLS1_3_VERSION) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD); |
| *out_alert = SSL_AD_UNEXPECTED_MESSAGE; |
| return ssl_open_record_error; |
| } |
| |
| CBS cbs = data, record_numbers; |
| if (!CBS_get_u16_length_prefixed(&cbs, &record_numbers) || |
| CBS_len(&cbs) != 0) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); |
| *out_alert = SSL_AD_DECODE_ERROR; |
| return ssl_open_record_error; |
| } |
| |
| while (CBS_len(&record_numbers) != 0) { |
| uint64_t epoch, seq; |
| if (!CBS_get_u64(&record_numbers, &epoch) || |
| !CBS_get_u64(&record_numbers, &seq)) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); |
| *out_alert = SSL_AD_DECODE_ERROR; |
| return ssl_open_record_error; |
| } |
| |
| // During the handshake, records must be ACKed at the same or higher epoch. |
| // See https://www.rfc-editor.org/errata/eid8108. Additionally, if the |
| // record does not fit in DTLSRecordNumber, it is definitely not a record |
| // number that we sent. |
| if ((ack_record_number.epoch() < ssl_encryption_application && |
| epoch > ack_record_number.epoch()) || |
| epoch > UINT16_MAX || seq > DTLSRecordNumber::kMaxSequence) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); |
| *out_alert = SSL_AD_ILLEGAL_PARAMETER; |
| return ssl_open_record_error; |
| } |
| |
| // Find the sent record that matches this ACK. |
| DTLSRecordNumber number(static_cast<uint16_t>(epoch), seq); |
| DTLSSentRecord *sent_record = nullptr; |
| if (ssl->d1->sent_records != nullptr) { |
| for (size_t i = 0; i < ssl->d1->sent_records->size(); i++) { |
| if ((*ssl->d1->sent_records)[i].number == number) { |
| sent_record = &(*ssl->d1->sent_records)[i]; |
| break; |
| } |
| } |
| } |
| if (sent_record == nullptr) { |
| // We may have sent this record and forgotten it, so this is not an error. |
| continue; |
| } |
| |
| // Mark each message as ACKed. |
| if (sent_record->first_msg == sent_record->last_msg) { |
| ssl->d1->outgoing_messages[sent_record->first_msg].acked.MarkRange( |
| sent_record->first_msg_start, sent_record->last_msg_end); |
| } else { |
| ssl->d1->outgoing_messages[sent_record->first_msg].acked.MarkRange( |
| sent_record->first_msg_start, SIZE_MAX); |
| for (size_t i = size_t{sent_record->first_msg} + 1; |
| i < sent_record->last_msg; i++) { |
| ssl->d1->outgoing_messages[i].acked.MarkRange(0, SIZE_MAX); |
| } |
| if (sent_record->last_msg_end != 0) { |
| ssl->d1->outgoing_messages[sent_record->last_msg].acked.MarkRange( |
| 0, sent_record->last_msg_end); |
| } |
| } |
| |
| // Clear the state so we don't bother re-marking the messages next time. |
| sent_record->first_msg = 0; |
| sent_record->first_msg_start = 0; |
| sent_record->last_msg = 0; |
| sent_record->last_msg_end = 0; |
| } |
| |
| // If the outgoing flight is now fully ACKed, we are done retransmitting. |
| if (std::all_of(ssl->d1->outgoing_messages.begin(), |
| ssl->d1->outgoing_messages.end(), |
| [](const auto &msg) { return msg.IsFullyAcked(); })) { |
| dtls1_stop_timer(ssl); |
| dtls_clear_outgoing_messages(ssl); |
| |
| // DTLS 1.3 defers the key update to when the message is ACKed. |
| if (ssl->s3->key_update_pending) { |
| if (!tls13_rotate_traffic_key(ssl, evp_aead_seal)) { |
| return ssl_open_record_error; |
| } |
| ssl->s3->key_update_pending = false; |
| } |
| |
| // Check for deferred messages. |
| if (ssl->d1->queued_key_update != QueuedKeyUpdate::kNone) { |
| int request_type = |
| ssl->d1->queued_key_update == QueuedKeyUpdate::kUpdateRequested |
| ? SSL_KEY_UPDATE_REQUESTED |
| : SSL_KEY_UPDATE_NOT_REQUESTED; |
| ssl->d1->queued_key_update = QueuedKeyUpdate::kNone; |
| if (!tls13_add_key_update(ssl, request_type)) { |
| return ssl_open_record_error; |
| } |
| } |
| } else { |
| // We may still be able to drop unused write epochs. |
| dtls_clear_unused_write_epochs(ssl); |
| |
| // TODO(crbug.com/42290594): Schedule a retransmit. The peer will have |
| // waited before sending the ACK, so a partial ACK suggests packet loss. |
| } |
| |
| ssl_do_msg_callback(ssl, /*is_write=*/0, SSL3_RT_ACK, data); |
| return ssl_open_record_discard; |
| } |
| |
| ssl_open_record_t dtls1_open_app_data(SSL *ssl, Span<uint8_t> *out, |
| size_t *out_consumed, uint8_t *out_alert, |
| Span<uint8_t> in) { |
| assert(!SSL_in_init(ssl)); |
| |
| uint8_t type; |
| DTLSRecordNumber record_number; |
| Span<uint8_t> record; |
| auto ret = dtls_open_record(ssl, &type, &record_number, &record, out_consumed, |
| out_alert, in); |
| if (ret != ssl_open_record_success) { |
| return ret; |
| } |
| |
| if (type == SSL3_RT_HANDSHAKE) { |
| // Process handshake fragments for DTLS 1.3 post-handshake messages. |
| if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) { |
| if (!dtls1_process_handshake_fragments(ssl, out_alert, record_number, |
| record)) { |
| return ssl_open_record_error; |
| } |
| return ssl_open_record_discard; |
| } |
| |
| // Parse the first fragment header to determine if this is a pre-CCS or |
| // post-CCS handshake record. DTLS resets handshake message numbers on each |
| // handshake, so renegotiations and retransmissions are ambiguous. |
| // |
| // TODO(crbug.com/42290594): Move this logic into |
| // |dtls1_process_handshake_fragments| and integrate it into DTLS 1.3 |
| // retransmit conditions. |
| CBS cbs, body; |
| struct hm_header_st msg_hdr; |
| CBS_init(&cbs, record.data(), record.size()); |
| if (!dtls1_parse_fragment(&cbs, &msg_hdr, &body)) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_HANDSHAKE_RECORD); |
| *out_alert = SSL_AD_DECODE_ERROR; |
| return ssl_open_record_error; |
| } |
| |
| if (msg_hdr.type == SSL3_MT_FINISHED && |
| msg_hdr.seq == ssl->d1->handshake_read_seq - 1) { |
| if (!ssl->d1->sending_flight && msg_hdr.frag_off == 0) { |
| // Retransmit our last flight of messages. If the peer sends the second |
| // Finished, they may not have received ours. Only do this for the |
| // first fragment, in case the Finished was fragmented. |
| // |
| // This is not really a timeout, but increment the timeout count so we |
| // eventually give up. |
| ssl->d1->num_timeouts++; |
| ssl->d1->sending_flight = true; |
| } |
| return ssl_open_record_discard; |
| } |
| |
| // Otherwise, this is a pre-CCS handshake message from an unsupported |
| // renegotiation attempt. Fall through to the error path. |
| } |
| |
| if (type == SSL3_RT_ACK) { |
| return dtls1_process_ack(ssl, out_alert, record_number, record); |
| } |
| |
| if (type != SSL3_RT_APPLICATION_DATA) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD); |
| *out_alert = SSL_AD_UNEXPECTED_MESSAGE; |
| return ssl_open_record_error; |
| } |
| |
| if (record.empty()) { |
| return ssl_open_record_discard; |
| } |
| |
| *out = record; |
| return ssl_open_record_success; |
| } |
| |
| int dtls1_write_app_data(SSL *ssl, bool *out_needs_handshake, |
| size_t *out_bytes_written, Span<const uint8_t> in) { |
| assert(!SSL_in_init(ssl)); |
| *out_needs_handshake = false; |
| |
| if (ssl->s3->write_shutdown != ssl_shutdown_none) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN); |
| return -1; |
| } |
| |
| // DTLS does not split the input across records. |
| if (in.size() > SSL3_RT_MAX_PLAIN_LENGTH) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_DTLS_MESSAGE_TOO_BIG); |
| return -1; |
| } |
| |
| if (in.empty()) { |
| *out_bytes_written = 0; |
| return 1; |
| } |
| |
| // TODO(crbug.com/381113363): Use the 0-RTT epoch if writing 0-RTT. |
| int ret = dtls1_write_record(ssl, SSL3_RT_APPLICATION_DATA, in, |
| ssl->d1->write_epoch.epoch()); |
| if (ret <= 0) { |
| return ret; |
| } |
| *out_bytes_written = in.size(); |
| return 1; |
| } |
| |
| int dtls1_write_record(SSL *ssl, int type, Span<const uint8_t> in, |
| uint16_t epoch) { |
| SSLBuffer *buf = &ssl->s3->write_buffer; |
| assert(in.size() <= SSL3_RT_MAX_PLAIN_LENGTH); |
| // There should never be a pending write buffer in DTLS. One can't write half |
| // a datagram, so the write buffer is always dropped in |
| // |ssl_write_buffer_flush|. |
| assert(buf->empty()); |
| |
| if (in.size() > SSL3_RT_MAX_PLAIN_LENGTH) { |
| OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); |
| return -1; |
| } |
| |
| DTLSRecordNumber record_number; |
| size_t ciphertext_len; |
| if (!buf->EnsureCap(dtls_seal_prefix_len(ssl, epoch), |
| in.size() + SSL_max_seal_overhead(ssl)) || |
| !dtls_seal_record(ssl, &record_number, buf->remaining().data(), |
| &ciphertext_len, buf->remaining().size(), type, |
| in.data(), in.size(), epoch)) { |
| buf->Clear(); |
| return -1; |
| } |
| buf->DidWrite(ciphertext_len); |
| |
| int ret = ssl_write_buffer_flush(ssl); |
| if (ret <= 0) { |
| return ret; |
| } |
| return 1; |
| } |
| |
| int dtls1_dispatch_alert(SSL *ssl) { |
| int ret = dtls1_write_record(ssl, SSL3_RT_ALERT, ssl->s3->send_alert, |
| ssl->d1->write_epoch.epoch()); |
| if (ret <= 0) { |
| return ret; |
| } |
| ssl->s3->alert_dispatch = false; |
| |
| // If the alert is fatal, flush the BIO now. |
| if (ssl->s3->send_alert[0] == SSL3_AL_FATAL) { |
| BIO_flush(ssl->wbio.get()); |
| } |
| |
| ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_ALERT, ssl->s3->send_alert); |
| |
| int alert = (ssl->s3->send_alert[0] << 8) | ssl->s3->send_alert[1]; |
| ssl_do_info_callback(ssl, SSL_CB_WRITE_ALERT, alert); |
| |
| return 1; |
| } |
| |
| BSSL_NAMESPACE_END |
