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e8d0746b88
boringssl/ssl/d1_both.cc
David Benjamin e8d0746b88 Prevent writing when write_shutdown is set. 
Ideally we'd put this deep in the record layer, but sending alerts
currently awkwardly sets the field early, so we can't quite lock it out
this deep down.

This is mostly a sanity-check, but a later CL will fix SSL_shutdown's
post-handshake message processing, so this will help catch errors there.

Change-Id: I78e627c19547dbcdc85fb168795240d692baf031
Reviewed-on: https://boringssl-review.googlesource.com/21884
Commit-Queue: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Steven Valdez <svaldez@google.com>
2017-10-17 20:18:21 +00:00

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/*
* 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.
static void dtls1_hm_fragment_free(hm_fragment *frag) {
if (frag == NULL) {
return;
}
OPENSSL_free(frag->data);
OPENSSL_free(frag->reassembly);
OPENSSL_free(frag);
}
static hm_fragment *dtls1_hm_fragment_new(const struct hm_header_st *msg_hdr) {
ScopedCBB cbb;
hm_fragment *frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
if (frag == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return NULL;
}
OPENSSL_memset(frag, 0, sizeof(hm_fragment));
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);
goto err;
}
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);
goto err;
}
// 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);
goto err;
}
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);
goto err;
}
OPENSSL_memset(frag->reassembly, 0, bitmask_len);
}
return frag;
err:
dtls1_hm_fragment_free(frag);
return NULL;
}
// 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) {
hm_fragment *frag = ssl->d1->incoming_messages[ssl->d1->handshake_read_seq %
SSL_MAX_HANDSHAKE_FLIGHT];
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];
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.
frag = dtls1_hm_fragment_new(msg_hdr);
if (frag == NULL) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return NULL;
}
ssl->d1->incoming_messages[idx] = frag;
return frag;
}
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;
}
hm_fragment *frag = ssl->d1->incoming_messages[ssl->d1->handshake_read_seq %
SSL_MAX_HANDSHAKE_FLIGHT];
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;
dtls1_hm_fragment_free(ssl->d1->incoming_messages[index]);
ssl->d1->incoming_messages[index] = NULL;
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;
}
}
void dtls_clear_incoming_messages(SSL *ssl) {
for (size_t i = 0; i < SSL_MAX_HANDSHAKE_FLIGHT; i++) {
dtls1_hm_fragment_free(ssl->d1->incoming_messages[i]);
ssl->d1->incoming_messages[i] = NULL;
}
}
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] != NULL) {
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_clear_outgoing_messages(SSL *ssl) {
for (size_t i = 0; i < ssl->d1->outgoing_messages_len; i++) {
OPENSSL_free(ssl->d1->outgoing_messages[i].data);
ssl->d1->outgoing_messages[i].data = NULL;
}
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;
}
// 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, int 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 ||
data.size() > 0xffffffff) {
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, 0 /* handshake */, std::move(data));
}
bool dtls1_add_change_cipher_spec(SSL *ssl) {
return add_outgoing(ssl, 1 /* 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->rwstate = SSL_WRITING;
ret = bio_ret;
goto err;
}
}
if (BIO_flush(ssl->wbio) <= 0) {
ssl->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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