--- /dev/null
+/*
+ * DTLS implementation written by Nagendra Modadugu
+ * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2005 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).
+ *
+ */
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ *
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to. The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code. The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ *
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ *
+ * 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 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 acknowledgement:
+ * "This product includes cryptographic software written by
+ * Eric Young (eay@cryptsoft.com)"
+ * The word 'cryptographic' can be left out if the rouines from the library
+ * being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from
+ * the apps directory (application code) you must include an acknowledgement:
+ * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS 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 AUTHOR OR 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.
+ *
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed. i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.] */
+
+#include <openssl/ssl.h>
+
+#include <assert.h>
+#include <limits.h>
+#include <string.h>
+
+#include <openssl/buf.h>
+#include <openssl/err.h>
+#include <openssl/evp.h>
+#include <openssl/mem.h>
+#include <openssl/rand.h>
+
+#include "../crypto/internal.h"
+#include "internal.h"
+
+
+namespace bssl {
+
+// TODO(davidben): 28 comes from the size of IP + UDP header. Is this reasonable
+// for these values? Notably, why is kMinMTU a function of the transport
+// protocol's overhead rather than, say, what's needed to hold a minimally-sized
+// handshake fragment plus protocol overhead.
+
+// kMinMTU is the minimum acceptable MTU value.
+static const unsigned int kMinMTU = 256 - 28;
+
+// kDefaultMTU is the default MTU value to use if neither the user nor
+// the underlying BIO supplies one.
+static const unsigned int kDefaultMTU = 1500 - 28;
+
+
+// Receiving handshake messages.
+
+hm_fragment::~hm_fragment() {
+ OPENSSL_free(data);
+ OPENSSL_free(reassembly);
+}
+
+static UniquePtr<hm_fragment> dtls1_hm_fragment_new(
+ const struct hm_header_st *msg_hdr) {
+ ScopedCBB cbb;
+ UniquePtr<hm_fragment> frag = MakeUnique<hm_fragment>();
+ if (!frag) {
+ return nullptr;
+ }
+ frag->type = msg_hdr->type;
+ frag->seq = msg_hdr->seq;
+ frag->msg_len = msg_hdr->msg_len;
+
+ // Allocate space for the reassembled message and fill in the header.
+ frag->data =
+ (uint8_t *)OPENSSL_malloc(DTLS1_HM_HEADER_LENGTH + msg_hdr->msg_len);
+ if (frag->data == NULL) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
+ return nullptr;
+ }
+
+ if (!CBB_init_fixed(cbb.get(), frag->data, DTLS1_HM_HEADER_LENGTH) ||
+ !CBB_add_u8(cbb.get(), msg_hdr->type) ||
+ !CBB_add_u24(cbb.get(), msg_hdr->msg_len) ||
+ !CBB_add_u16(cbb.get(), msg_hdr->seq) ||
+ !CBB_add_u24(cbb.get(), 0 /* frag_off */) ||
+ !CBB_add_u24(cbb.get(), msg_hdr->msg_len) ||
+ !CBB_finish(cbb.get(), NULL, NULL)) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
+ return nullptr;
+ }
+
+ // If the handshake message is empty, |frag->reassembly| is NULL.
+ if (msg_hdr->msg_len > 0) {
+ // Initialize reassembly bitmask.
+ if (msg_hdr->msg_len + 7 < msg_hdr->msg_len) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
+ return nullptr;
+ }
+ size_t bitmask_len = (msg_hdr->msg_len + 7) / 8;
+ frag->reassembly = (uint8_t *)OPENSSL_malloc(bitmask_len);
+ if (frag->reassembly == NULL) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
+ return nullptr;
+ }
+ OPENSSL_memset(frag->reassembly, 0, bitmask_len);
+ }
+
+ return frag;
+}
+
+// bit_range returns a |uint8_t| with bits |start|, inclusive, to |end|,
+// exclusive, set.
+static uint8_t bit_range(size_t start, size_t end) {
+ return (uint8_t)(~((1u << start) - 1) & ((1u << end) - 1));
+}
+
+// dtls1_hm_fragment_mark marks bytes |start|, inclusive, to |end|, exclusive,
+// as received in |frag|. If |frag| becomes complete, it clears
+// |frag->reassembly|. The range must be within the bounds of |frag|'s message
+// and |frag->reassembly| must not be NULL.
+static void dtls1_hm_fragment_mark(hm_fragment *frag, size_t start,
+ size_t end) {
+ size_t msg_len = frag->msg_len;
+
+ if (frag->reassembly == NULL || start > end || end > msg_len) {
+ assert(0);
+ return;
+ }
+ // A zero-length message will never have a pending reassembly.
+ assert(msg_len > 0);
+
+ if (start == end) {
+ return;
+ }
+
+ if ((start >> 3) == (end >> 3)) {
+ frag->reassembly[start >> 3] |= bit_range(start & 7, end & 7);
+ } else {
+ frag->reassembly[start >> 3] |= bit_range(start & 7, 8);
+ for (size_t i = (start >> 3) + 1; i < (end >> 3); i++) {
+ frag->reassembly[i] = 0xff;
+ }
+ if ((end & 7) != 0) {
+ frag->reassembly[end >> 3] |= bit_range(0, end & 7);
+ }
+ }
+
+ // Check if the fragment is complete.
+ for (size_t i = 0; i < (msg_len >> 3); i++) {
+ if (frag->reassembly[i] != 0xff) {
+ return;
+ }
+ }
+ if ((msg_len & 7) != 0 &&
+ frag->reassembly[msg_len >> 3] != bit_range(0, msg_len & 7)) {
+ return;
+ }
+
+ OPENSSL_free(frag->reassembly);
+ frag->reassembly = NULL;
+}
+
+// dtls1_is_current_message_complete returns whether the current handshake
+// message is complete.
+static bool dtls1_is_current_message_complete(const SSL *ssl) {
+ size_t idx = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT;
+ hm_fragment *frag = ssl->d1->incoming_messages[idx].get();
+ return frag != NULL && frag->reassembly == NULL;
+}
+
+// dtls1_get_incoming_message returns the incoming message corresponding to
+// |msg_hdr|. If none exists, it creates a new one and inserts it in the
+// queue. Otherwise, it checks |msg_hdr| is consistent with the existing one. It
+// returns NULL on failure. The caller does not take ownership of the result.
+static hm_fragment *dtls1_get_incoming_message(
+ SSL *ssl, uint8_t *out_alert, const struct hm_header_st *msg_hdr) {
+ if (msg_hdr->seq < ssl->d1->handshake_read_seq ||
+ msg_hdr->seq - ssl->d1->handshake_read_seq >= SSL_MAX_HANDSHAKE_FLIGHT) {
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return NULL;
+ }
+
+ size_t idx = msg_hdr->seq % SSL_MAX_HANDSHAKE_FLIGHT;
+ hm_fragment *frag = ssl->d1->incoming_messages[idx].get();
+ if (frag != NULL) {
+ assert(frag->seq == msg_hdr->seq);
+ // The new fragment must be compatible with the previous fragments from this
+ // message.
+ if (frag->type != msg_hdr->type ||
+ frag->msg_len != msg_hdr->msg_len) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_FRAGMENT_MISMATCH);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return NULL;
+ }
+ return frag;
+ }
+
+ // This is the first fragment from this message.
+ ssl->d1->incoming_messages[idx] = dtls1_hm_fragment_new(msg_hdr);
+ if (!ssl->d1->incoming_messages[idx]) {
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return NULL;
+ }
+ return ssl->d1->incoming_messages[idx].get();
+}
+
+ssl_open_record_t dtls1_open_handshake(SSL *ssl, size_t *out_consumed,
+ uint8_t *out_alert, Span<uint8_t> in) {
+ uint8_t type;
+ Span<uint8_t> record;
+ auto ret = dtls_open_record(ssl, &type, &record, out_consumed, out_alert, in);
+ if (ret != ssl_open_record_success) {
+ return ret;
+ }
+
+ switch (type) {
+ case SSL3_RT_APPLICATION_DATA:
+ // Unencrypted application data records are always illegal.
+ if (ssl->s3->aead_read_ctx->is_null_cipher()) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
+ *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
+ return ssl_open_record_error;
+ }
+
+ // Out-of-order application data may be received between ChangeCipherSpec
+ // and finished. Discard it.
+ return ssl_open_record_discard;
+
+ case SSL3_RT_CHANGE_CIPHER_SPEC:
+ // We do not support renegotiation, so encrypted ChangeCipherSpec records
+ // are illegal.
+ if (!ssl->s3->aead_read_ctx->is_null_cipher()) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
+ *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
+ return ssl_open_record_error;
+ }
+
+ if (record.size() != 1u || record[0] != SSL3_MT_CCS) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_CHANGE_CIPHER_SPEC);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return ssl_open_record_error;
+ }
+
+ // Flag the ChangeCipherSpec for later.
+ ssl->d1->has_change_cipher_spec = true;
+ ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_CHANGE_CIPHER_SPEC,
+ record);
+ return ssl_open_record_success;
+
+ case SSL3_RT_HANDSHAKE:
+ // Break out to main processing.
+ break;
+
+ default:
+ OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
+ *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
+ return ssl_open_record_error;
+ }
+
+ CBS cbs;
+ CBS_init(&cbs, record.data(), record.size());
+ while (CBS_len(&cbs) > 0) {
+ // Read a handshake fragment.
+ struct hm_header_st msg_hdr;
+ CBS body;
+ 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;
+ }
+
+ const size_t frag_off = msg_hdr.frag_off;
+ const size_t frag_len = msg_hdr.frag_len;
+ const size_t msg_len = msg_hdr.msg_len;
+ if (frag_off > msg_len || frag_off + frag_len < frag_off ||
+ frag_off + frag_len > msg_len ||
+ msg_len > ssl_max_handshake_message_len(ssl)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESSIVE_MESSAGE_SIZE);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return ssl_open_record_error;
+ }
+
+ // The encrypted epoch in DTLS has only one handshake message.
+ if (ssl->d1->r_epoch == 1 && msg_hdr.seq != ssl->d1->handshake_read_seq) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
+ *out_alert = SSL_AD_UNEXPECTED_MESSAGE;
+ return ssl_open_record_error;
+ }
+
+ if (msg_hdr.seq < ssl->d1->handshake_read_seq ||
+ msg_hdr.seq >
+ (unsigned)ssl->d1->handshake_read_seq + SSL_MAX_HANDSHAKE_FLIGHT) {
+ // Ignore fragments from the past, or ones too far in the future.
+ continue;
+ }
+
+ hm_fragment *frag = dtls1_get_incoming_message(ssl, out_alert, &msg_hdr);
+ if (frag == NULL) {
+ return ssl_open_record_error;
+ }
+ assert(frag->msg_len == msg_len);
+
+ if (frag->reassembly == NULL) {
+ // The message is already assembled.
+ continue;
+ }
+ assert(msg_len > 0);
+
+ // Copy the body into the fragment.
+ OPENSSL_memcpy(frag->data + DTLS1_HM_HEADER_LENGTH + frag_off,
+ CBS_data(&body), CBS_len(&body));
+ dtls1_hm_fragment_mark(frag, frag_off, frag_off + frag_len);
+ }
+
+ return ssl_open_record_success;
+}
+
+bool dtls1_get_message(SSL *ssl, SSLMessage *out) {
+ if (!dtls1_is_current_message_complete(ssl)) {
+ return false;
+ }
+
+ size_t idx = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT;
+ hm_fragment *frag = ssl->d1->incoming_messages[idx].get();
+ out->type = frag->type;
+ CBS_init(&out->body, frag->data + DTLS1_HM_HEADER_LENGTH, frag->msg_len);
+ CBS_init(&out->raw, frag->data, DTLS1_HM_HEADER_LENGTH + frag->msg_len);
+ out->is_v2_hello = false;
+ if (!ssl->s3->has_message) {
+ ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_HANDSHAKE, out->raw);
+ ssl->s3->has_message = true;
+ }
+ return true;
+}
+
+void dtls1_next_message(SSL *ssl) {
+ assert(ssl->s3->has_message);
+ assert(dtls1_is_current_message_complete(ssl));
+ size_t index = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT;
+ ssl->d1->incoming_messages[index].reset();
+ ssl->d1->handshake_read_seq++;
+ ssl->s3->has_message = false;
+ // If we previously sent a flight, mark it as having a reply, so
+ // |on_handshake_complete| can manage post-handshake retransmission.
+ if (ssl->d1->outgoing_messages_complete) {
+ ssl->d1->flight_has_reply = true;
+ }
+}
+
+bool dtls_has_unprocessed_handshake_data(const SSL *ssl) {
+ if (ssl->d1->has_change_cipher_spec) {
+ return true;
+ }
+
+ size_t current = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT;
+ for (size_t i = 0; i < SSL_MAX_HANDSHAKE_FLIGHT; i++) {
+ // Skip the current message.
+ if (ssl->s3->has_message && i == current) {
+ assert(dtls1_is_current_message_complete(ssl));
+ continue;
+ }
+ if (ssl->d1->incoming_messages[i] != nullptr) {
+ return true;
+ }
+ }
+ return false;
+}
+
+bool dtls1_parse_fragment(CBS *cbs, struct hm_header_st *out_hdr,
+ CBS *out_body) {
+ OPENSSL_memset(out_hdr, 0x00, sizeof(struct hm_header_st));
+
+ if (!CBS_get_u8(cbs, &out_hdr->type) ||
+ !CBS_get_u24(cbs, &out_hdr->msg_len) ||
+ !CBS_get_u16(cbs, &out_hdr->seq) ||
+ !CBS_get_u24(cbs, &out_hdr->frag_off) ||
+ !CBS_get_u24(cbs, &out_hdr->frag_len) ||
+ !CBS_get_bytes(cbs, out_body, out_hdr->frag_len)) {
+ return false;
+ }
+
+ return true;
+}
+
+ssl_open_record_t dtls1_open_change_cipher_spec(SSL *ssl, size_t *out_consumed,
+ uint8_t *out_alert,
+ Span<uint8_t> in) {
+ if (!ssl->d1->has_change_cipher_spec) {
+ // dtls1_open_handshake processes both handshake and ChangeCipherSpec.
+ auto ret = dtls1_open_handshake(ssl, out_consumed, out_alert, in);
+ if (ret != ssl_open_record_success) {
+ return ret;
+ }
+ }
+ if (ssl->d1->has_change_cipher_spec) {
+ ssl->d1->has_change_cipher_spec = false;
+ return ssl_open_record_success;
+ }
+ return ssl_open_record_discard;
+}
+
+
+// Sending handshake messages.
+
+void DTLS_OUTGOING_MESSAGE::Clear() {
+ OPENSSL_free(data);
+ data = nullptr;
+}
+
+void dtls_clear_outgoing_messages(SSL *ssl) {
+ for (size_t i = 0; i < ssl->d1->outgoing_messages_len; i++) {
+ ssl->d1->outgoing_messages[i].Clear();
+ }
+ ssl->d1->outgoing_messages_len = 0;
+ ssl->d1->outgoing_written = 0;
+ ssl->d1->outgoing_offset = 0;
+ ssl->d1->outgoing_messages_complete = false;
+ ssl->d1->flight_has_reply = false;
+}
+
+bool dtls1_init_message(SSL *ssl, CBB *cbb, CBB *body, uint8_t type) {
+ // Pick a modest size hint to save most of the |realloc| calls.
+ if (!CBB_init(cbb, 64) ||
+ !CBB_add_u8(cbb, type) ||
+ !CBB_add_u24(cbb, 0 /* length (filled in later) */) ||
+ !CBB_add_u16(cbb, ssl->d1->handshake_write_seq) ||
+ !CBB_add_u24(cbb, 0 /* offset */) ||
+ !CBB_add_u24_length_prefixed(cbb, body)) {
+ return false;
+ }
+
+ return true;
+}
+
+bool dtls1_finish_message(SSL *ssl, CBB *cbb, Array<uint8_t> *out_msg) {
+ if (!CBBFinishArray(cbb, out_msg) ||
+ out_msg->size() < DTLS1_HM_HEADER_LENGTH) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return false;
+ }
+
+ // Fix up the header. Copy the fragment length into the total message
+ // length.
+ OPENSSL_memcpy(out_msg->data() + 1,
+ out_msg->data() + DTLS1_HM_HEADER_LENGTH - 3, 3);
+ return true;
+}
+
+// ssl_size_t_greater_than_32_bits returns whether |v| exceeds the bounds of a
+// 32-bit value. The obvious thing doesn't work because, in some 32-bit build
+// configurations, the compiler warns that the test is always false and breaks
+// the build.
+static bool ssl_size_t_greater_than_32_bits(size_t v) {
+#if defined(OPENSSL_64_BIT)
+ return v > 0xffffffff;
+#elif defined(OPENSSL_32_BIT)
+ return false;
+#else
+#error "Building for neither 32- nor 64-bits."
+#endif
+}
+
+// add_outgoing adds a new handshake message or ChangeCipherSpec to the current
+// outgoing flight. It returns true on success and false on error.
+static bool add_outgoing(SSL *ssl, bool is_ccs, Array<uint8_t> data) {
+ if (ssl->d1->outgoing_messages_complete) {
+ // If we've begun writing a new flight, we received the peer flight. Discard
+ // the timer and the our flight.
+ dtls1_stop_timer(ssl);
+ dtls_clear_outgoing_messages(ssl);
+ }
+
+ static_assert(SSL_MAX_HANDSHAKE_FLIGHT <
+ (1 << 8 * sizeof(ssl->d1->outgoing_messages_len)),
+ "outgoing_messages_len is too small");
+ if (ssl->d1->outgoing_messages_len >= SSL_MAX_HANDSHAKE_FLIGHT ||
+ ssl_size_t_greater_than_32_bits(data.size())) {
+ assert(false);
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return false;
+ }
+
+ if (!is_ccs) {
+ // TODO(svaldez): Move this up a layer to fix abstraction for SSLTranscript
+ // on hs.
+ if (ssl->s3->hs != NULL &&
+ !ssl->s3->hs->transcript.Update(data)) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return false;
+ }
+ ssl->d1->handshake_write_seq++;
+ }
+
+ DTLS_OUTGOING_MESSAGE *msg =
+ &ssl->d1->outgoing_messages[ssl->d1->outgoing_messages_len];
+ size_t len;
+ data.Release(&msg->data, &len);
+ msg->len = len;
+ msg->epoch = ssl->d1->w_epoch;
+ msg->is_ccs = is_ccs;
+
+ ssl->d1->outgoing_messages_len++;
+ return true;
+}
+
+bool dtls1_add_message(SSL *ssl, Array<uint8_t> data) {
+ return add_outgoing(ssl, false /* handshake */, std::move(data));
+}
+
+bool dtls1_add_change_cipher_spec(SSL *ssl) {
+ return add_outgoing(ssl, true /* ChangeCipherSpec */, Array<uint8_t>());
+}
+
+bool dtls1_add_alert(SSL *ssl, uint8_t level, uint8_t desc) {
+ // The |add_alert| path is only used for warning alerts for now, which DTLS
+ // never sends. This will be implemented later once closure alerts are
+ // converted.
+ assert(false);
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return false;
+}
+
+// dtls1_update_mtu updates the current MTU from the BIO, ensuring it is above
+// the minimum.
+static void dtls1_update_mtu(SSL *ssl) {
+ // TODO(davidben): No consumer implements |BIO_CTRL_DGRAM_SET_MTU| and the
+ // only |BIO_CTRL_DGRAM_QUERY_MTU| implementation could use
+ // |SSL_set_mtu|. Does this need to be so complex?
+ if (ssl->d1->mtu < dtls1_min_mtu() &&
+ !(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
+ long mtu = BIO_ctrl(ssl->wbio, BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
+ if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) {
+ ssl->d1->mtu = (unsigned)mtu;
+ } else {
+ ssl->d1->mtu = kDefaultMTU;
+ BIO_ctrl(ssl->wbio, BIO_CTRL_DGRAM_SET_MTU, ssl->d1->mtu, NULL);
+ }
+ }
+
+ // The MTU should be above the minimum now.
+ assert(ssl->d1->mtu >= dtls1_min_mtu());
+}
+
+enum seal_result_t {
+ seal_error,
+ seal_no_progress,
+ seal_partial,
+ seal_success,
+};
+
+// seal_next_message seals |msg|, which must be the next message, to |out|. If
+// progress was made, it returns |seal_partial| or |seal_success| and sets
+// |*out_len| to the number of bytes written.
+static enum seal_result_t seal_next_message(SSL *ssl, uint8_t *out,
+ size_t *out_len, size_t max_out,
+ const DTLS_OUTGOING_MESSAGE *msg) {
+ assert(ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len);
+ assert(msg == &ssl->d1->outgoing_messages[ssl->d1->outgoing_written]);
+
+ enum dtls1_use_epoch_t use_epoch = dtls1_use_current_epoch;
+ if (ssl->d1->w_epoch >= 1 && msg->epoch == ssl->d1->w_epoch - 1) {
+ use_epoch = dtls1_use_previous_epoch;
+ } else if (msg->epoch != ssl->d1->w_epoch) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return seal_error;
+ }
+
+ size_t overhead = dtls_max_seal_overhead(ssl, use_epoch);
+ size_t prefix = dtls_seal_prefix_len(ssl, use_epoch);
+
+ if (msg->is_ccs) {
+ // Check there is room for the ChangeCipherSpec.
+ static const uint8_t kChangeCipherSpec[1] = {SSL3_MT_CCS};
+ if (max_out < sizeof(kChangeCipherSpec) + overhead) {
+ return seal_no_progress;
+ }
+
+ if (!dtls_seal_record(ssl, out, out_len, max_out,
+ SSL3_RT_CHANGE_CIPHER_SPEC, kChangeCipherSpec,
+ sizeof(kChangeCipherSpec), use_epoch)) {
+ return seal_error;
+ }
+
+ ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_CHANGE_CIPHER_SPEC,
+ kChangeCipherSpec);
+ return seal_success;
+ }
+
+ // DTLS messages are serialized as a single fragment in |msg|.
+ CBS cbs, body;
+ struct hm_header_st hdr;
+ CBS_init(&cbs, msg->data, msg->len);
+ if (!dtls1_parse_fragment(&cbs, &hdr, &body) ||
+ hdr.frag_off != 0 ||
+ hdr.frag_len != CBS_len(&body) ||
+ hdr.msg_len != CBS_len(&body) ||
+ !CBS_skip(&body, ssl->d1->outgoing_offset) ||
+ CBS_len(&cbs) != 0) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return seal_error;
+ }
+
+ // Determine how much progress can be made.
+ if (max_out < DTLS1_HM_HEADER_LENGTH + 1 + overhead || max_out < prefix) {
+ return seal_no_progress;
+ }
+ size_t todo = CBS_len(&body);
+ if (todo > max_out - DTLS1_HM_HEADER_LENGTH - overhead) {
+ todo = max_out - DTLS1_HM_HEADER_LENGTH - overhead;
+ }
+
+ // Assemble a fragment, to be sealed in-place.
+ ScopedCBB cbb;
+ uint8_t *frag = out + prefix;
+ size_t max_frag = max_out - prefix, frag_len;
+ if (!CBB_init_fixed(cbb.get(), frag, max_frag) ||
+ !CBB_add_u8(cbb.get(), hdr.type) ||
+ !CBB_add_u24(cbb.get(), hdr.msg_len) ||
+ !CBB_add_u16(cbb.get(), hdr.seq) ||
+ !CBB_add_u24(cbb.get(), ssl->d1->outgoing_offset) ||
+ !CBB_add_u24(cbb.get(), todo) ||
+ !CBB_add_bytes(cbb.get(), CBS_data(&body), todo) ||
+ !CBB_finish(cbb.get(), NULL, &frag_len)) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return seal_error;
+ }
+
+ ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_HANDSHAKE,
+ MakeSpan(frag, frag_len));
+
+ if (!dtls_seal_record(ssl, out, out_len, max_out, SSL3_RT_HANDSHAKE,
+ out + prefix, frag_len, use_epoch)) {
+ return seal_error;
+ }
+
+ if (todo == CBS_len(&body)) {
+ // The next message is complete.
+ ssl->d1->outgoing_offset = 0;
+ return seal_success;
+ }
+
+ ssl->d1->outgoing_offset += todo;
+ return seal_partial;
+}
+
+// seal_next_packet writes as much of the next flight as possible to |out| and
+// advances |ssl->d1->outgoing_written| and |ssl->d1->outgoing_offset| as
+// appropriate.
+static bool seal_next_packet(SSL *ssl, uint8_t *out, size_t *out_len,
+ size_t max_out) {
+ bool made_progress = false;
+ size_t total = 0;
+ assert(ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len);
+ for (; ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len;
+ ssl->d1->outgoing_written++) {
+ const DTLS_OUTGOING_MESSAGE *msg =
+ &ssl->d1->outgoing_messages[ssl->d1->outgoing_written];
+ size_t len;
+ enum seal_result_t ret = seal_next_message(ssl, out, &len, max_out, msg);
+ switch (ret) {
+ case seal_error:
+ return false;
+
+ case seal_no_progress:
+ goto packet_full;
+
+ case seal_partial:
+ case seal_success:
+ out += len;
+ max_out -= len;
+ total += len;
+ made_progress = true;
+
+ if (ret == seal_partial) {
+ goto packet_full;
+ }
+ break;
+ }
+ }
+
+packet_full:
+ // The MTU was too small to make any progress.
+ if (!made_progress) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_MTU_TOO_SMALL);
+ return false;
+ }
+
+ *out_len = total;
+ return true;
+}
+
+static int send_flight(SSL *ssl) {
+ if (ssl->s3->write_shutdown != ssl_shutdown_none) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN);
+ return -1;
+ }
+
+ dtls1_update_mtu(ssl);
+
+ int ret = -1;
+ uint8_t *packet = (uint8_t *)OPENSSL_malloc(ssl->d1->mtu);
+ if (packet == NULL) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ while (ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len) {
+ uint8_t old_written = ssl->d1->outgoing_written;
+ uint32_t old_offset = ssl->d1->outgoing_offset;
+
+ size_t packet_len;
+ if (!seal_next_packet(ssl, packet, &packet_len, ssl->d1->mtu)) {
+ goto err;
+ }
+
+ int bio_ret = BIO_write(ssl->wbio, packet, packet_len);
+ if (bio_ret <= 0) {
+ // Retry this packet the next time around.
+ ssl->d1->outgoing_written = old_written;
+ ssl->d1->outgoing_offset = old_offset;
+ ssl->s3->rwstate = SSL_WRITING;
+ ret = bio_ret;
+ goto err;
+ }
+ }
+
+ if (BIO_flush(ssl->wbio) <= 0) {
+ ssl->s3->rwstate = SSL_WRITING;
+ goto err;
+ }
+
+ ret = 1;
+
+err:
+ OPENSSL_free(packet);
+ return ret;
+}
+
+int dtls1_flush_flight(SSL *ssl) {
+ ssl->d1->outgoing_messages_complete = true;
+ // Start the retransmission timer for the next flight (if any).
+ dtls1_start_timer(ssl);
+ return send_flight(ssl);
+}
+
+int dtls1_retransmit_outgoing_messages(SSL *ssl) {
+ // Rewind to the start of the flight and write it again.
+ //
+ // TODO(davidben): This does not allow retransmits to be resumed on
+ // non-blocking write.
+ ssl->d1->outgoing_written = 0;
+ ssl->d1->outgoing_offset = 0;
+
+ return send_flight(ssl);
+}
+
+unsigned int dtls1_min_mtu(void) {
+ return kMinMTU;
+}
+
+} // namespace bssl
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