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09eb655e5c
boringssl/ssl/d1_both.c
David Benjamin 09eb655e5c Simplify ssl_get_message somewhat. 
It still places the current message all over the place, but remove the
bizarre init_num/error/ok split. Now callers get the message length out
of init_num, which mirrors init_msg. Also fix some signedness.

Change-Id: Ic2e97b6b99e234926504ff217b8aedae85ba6596
Reviewed-on: https://boringssl-review.googlesource.com/8690
Reviewed-by: David Benjamin <davidben@google.com>
2016-07-11 23:01:32 +00:00

826 lines
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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 <openssl/x509.h>
#include "internal.h"
/* 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) {
hm_fragment *frag = OPENSSL_malloc(sizeof(hm_fragment));
if (frag == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return NULL;
}
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 = OPENSSL_malloc(DTLS1_HM_HEADER_LENGTH + msg_hdr->msg_len);
if (frag->data == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
CBB cbb;
if (!CBB_init_fixed(&cbb, frag->data, DTLS1_HM_HEADER_LENGTH) ||
!CBB_add_u8(&cbb, msg_hdr->type) ||
!CBB_add_u24(&cbb, msg_hdr->msg_len) ||
!CBB_add_u16(&cbb, msg_hdr->seq) ||
!CBB_add_u24(&cbb, 0 /* frag_off */) ||
!CBB_add_u24(&cbb, msg_hdr->msg_len) ||
!CBB_finish(&cbb, NULL, NULL)) {
CBB_cleanup(&cbb);
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 = OPENSSL_malloc(bitmask_len);
if (frag->reassembly == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
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 i;
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 >> 3) == (end >> 3)) {
frag->reassembly[start >> 3] |= bit_range(start & 7, end & 7);
} else {
frag->reassembly[start >> 3] |= bit_range(start & 7, 8);
for (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 (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 one if the current handshake
* message is complete and zero otherwise. */
static int dtls1_is_current_message_complete(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_pop_message removes the current handshake message, which must be
* complete, and advances to the next one. */
static void dtls1_pop_message(SSL *ssl) {
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++;
}
/* 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, 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) {
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);
ssl3_send_alert(ssl, SSL3_AL_FATAL, 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) {
return NULL;
}
ssl->d1->incoming_messages[idx] = frag;
return frag;
}
/* dtls1_process_handshake_record reads a handshake record and processes it. It
* returns one if the record was successfully processed and 0 or -1 on error. */
static int dtls1_process_handshake_record(SSL *ssl) {
SSL3_RECORD *rr = &ssl->s3->rrec;
start:
if (rr->length == 0) {
int ret = dtls1_get_record(ssl);
if (ret <= 0) {
return ret;
}
}
/* Cross-epoch records are discarded, but we may receive out-of-order
* application data between ChangeCipherSpec and Finished or a ChangeCipherSpec
* before the appropriate point in the handshake. Those must be silently
* discarded.
*
* However, only allow the out-of-order records in the correct epoch.
* Application data must come in the encrypted epoch, and ChangeCipherSpec in
* the unencrypted epoch (we never renegotiate). Other cases fall through and
* fail with a fatal error. */
if ((rr->type == SSL3_RT_APPLICATION_DATA &&
ssl->s3->aead_read_ctx != NULL) ||
(rr->type == SSL3_RT_CHANGE_CIPHER_SPEC &&
ssl->s3->aead_read_ctx == NULL)) {
rr->length = 0;
goto start;
}
if (rr->type != SSL3_RT_HANDSHAKE) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
return -1;
}
CBS cbs;
CBS_init(&cbs, rr->data, rr->length);
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);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return -1;
}
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);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return -1;
}
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, &msg_hdr);
if (frag == NULL) {
return -1;
}
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. */
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);
}
rr->length = 0;
ssl_read_buffer_discard(ssl);
return 1;
}
int dtls1_get_message(SSL *ssl, int msg_type,
enum ssl_hash_message_t hash_message) {
if (ssl->s3->tmp.reuse_message) {
/* A ssl_dont_hash_message call cannot be combined with reuse_message; the
* ssl_dont_hash_message would have to have been applied to the previous
* call. */
assert(hash_message == ssl_hash_message);
assert(dtls1_is_current_message_complete(ssl));
ssl->s3->tmp.reuse_message = 0;
hash_message = ssl_dont_hash_message;
} else if (dtls1_is_current_message_complete(ssl)) {
dtls1_pop_message(ssl);
}
/* Process handshake records until the current message is ready. */
while (!dtls1_is_current_message_complete(ssl)) {
int ret = dtls1_process_handshake_record(ssl);
if (ret <= 0) {
return ret;
}
}
hm_fragment *frag = ssl->d1->incoming_messages[ssl->d1->handshake_read_seq %
SSL_MAX_HANDSHAKE_FLIGHT];
assert(frag != NULL);
assert(frag->reassembly == NULL);
assert(ssl->d1->handshake_read_seq == frag->seq);
/* TODO(davidben): This function has a lot of implicit outputs. Simplify the
* |ssl_get_message| API. */
ssl->s3->tmp.message_type = frag->type;
ssl->init_msg = frag->data + DTLS1_HM_HEADER_LENGTH;
ssl->init_num = frag->msg_len;
if (msg_type >= 0 && ssl->s3->tmp.message_type != msg_type) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
return -1;
}
if (hash_message == ssl_hash_message && !dtls1_hash_current_message(ssl)) {
return -1;
}
ssl_do_msg_callback(ssl, 0 /* read */, ssl->version, SSL3_RT_HANDSHAKE,
frag->data, ssl->init_num + DTLS1_HM_HEADER_LENGTH);
return 1;
}
int dtls1_hash_current_message(SSL *ssl) {
assert(dtls1_is_current_message_complete(ssl));
hm_fragment *frag = ssl->d1->incoming_messages[ssl->d1->handshake_read_seq %
SSL_MAX_HANDSHAKE_FLIGHT];
return ssl3_update_handshake_hash(ssl, frag->data,
DTLS1_HM_HEADER_LENGTH + frag->msg_len);
}
void dtls_clear_incoming_messages(SSL *ssl) {
size_t i;
for (i = 0; i < SSL_MAX_HANDSHAKE_FLIGHT; i++) {
dtls1_hm_fragment_free(ssl->d1->incoming_messages[i]);
ssl->d1->incoming_messages[i] = NULL;
}
}
int dtls1_parse_fragment(CBS *cbs, struct hm_header_st *out_hdr,
CBS *out_body) {
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 0;
}
return 1;
}
/* Sending handshake messages. */
static void dtls1_update_mtu(SSL *ssl) {
/* TODO(davidben): What is this code doing and do we need it? */
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());
}
/* dtls1_max_record_size returns the maximum record body length that may be
* written without exceeding the MTU. It accounts for any buffering installed on
* the write BIO. If no record may be written, it returns zero. */
static size_t dtls1_max_record_size(SSL *ssl) {
size_t ret = ssl->d1->mtu;
size_t overhead = ssl_max_seal_overhead(ssl);
if (ret <= overhead) {
return 0;
}
ret -= overhead;
size_t pending = BIO_wpending(ssl->wbio);
if (ret <= pending) {
return 0;
}
ret -= pending;
return ret;
}
static int dtls1_write_change_cipher_spec(SSL *ssl,
enum dtls1_use_epoch_t use_epoch) {
dtls1_update_mtu(ssl);
/* During the handshake, wbio is buffered to pack messages together. Flush the
* buffer if the ChangeCipherSpec would not fit in a packet. */
if (dtls1_max_record_size(ssl) == 0) {
int ret = BIO_flush(ssl->wbio);
if (ret <= 0) {
ssl->rwstate = SSL_WRITING;
return ret;
}
}
static const uint8_t kChangeCipherSpec[1] = {SSL3_MT_CCS};
int ret =
dtls1_write_record(ssl, SSL3_RT_CHANGE_CIPHER_SPEC, kChangeCipherSpec,
sizeof(kChangeCipherSpec), use_epoch);
if (ret <= 0) {
return ret;
}
ssl_do_msg_callback(ssl, 1 /* write */, ssl->version,
SSL3_RT_CHANGE_CIPHER_SPEC, kChangeCipherSpec,
sizeof(kChangeCipherSpec));
return 1;
}
/* dtls1_do_handshake_write writes handshake message |in| using the given epoch,
* starting |offset| bytes into the message body. It returns one on success. On
* error, it returns <= 0 and sets |*out_offset| to the number of bytes of body
* that were successfully written. This may be used to retry the write
* later. |in| must be a reassembled handshake message with the full DTLS
* handshake header. */
static int dtls1_do_handshake_write(SSL *ssl, size_t *out_offset,
const uint8_t *in, size_t offset,
size_t len,
enum dtls1_use_epoch_t use_epoch) {
dtls1_update_mtu(ssl);
int ret = -1;
CBB cbb;
CBB_zero(&cbb);
/* Allocate a temporary buffer to hold the message fragments to avoid
* clobbering the message. */
uint8_t *buf = OPENSSL_malloc(ssl->d1->mtu);
if (buf == NULL) {
goto err;
}
/* Although it may be sent as multiple fragments, a DTLS message must be sent
* serialized as a single fragment for purposes of |ssl_do_msg_callback| and
* the handshake hash. */
CBS cbs, body;
struct hm_header_st hdr;
CBS_init(&cbs, in, 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, offset) ||
CBS_len(&cbs) != 0) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
goto err;
}
do {
/* During the handshake, wbio is buffered to pack messages together. Flush
* the buffer if there isn't enough room to make progress. */
if (dtls1_max_record_size(ssl) < DTLS1_HM_HEADER_LENGTH + 1) {
int flush_ret = BIO_flush(ssl->wbio);
if (flush_ret <= 0) {
ssl->rwstate = SSL_WRITING;
ret = flush_ret;
goto err;
}
assert(BIO_wpending(ssl->wbio) == 0);
}
size_t todo = dtls1_max_record_size(ssl);
if (todo < DTLS1_HM_HEADER_LENGTH + 1) {
/* To make forward progress, the MTU must, at minimum, fit the handshake
* header and one byte of handshake body. */
OPENSSL_PUT_ERROR(SSL, SSL_R_MTU_TOO_SMALL);
goto err;
}
todo -= DTLS1_HM_HEADER_LENGTH;
if (todo > CBS_len(&body)) {
todo = CBS_len(&body);
}
if (todo >= (1u << 24)) {
todo = (1u << 24) - 1;
}
size_t buf_len;
if (!CBB_init_fixed(&cbb, buf, ssl->d1->mtu) ||
!CBB_add_u8(&cbb, hdr.type) ||
!CBB_add_u24(&cbb, hdr.msg_len) ||
!CBB_add_u16(&cbb, hdr.seq) ||
!CBB_add_u24(&cbb, offset) ||
!CBB_add_u24(&cbb, todo) ||
!CBB_add_bytes(&cbb, CBS_data(&body), todo) ||
!CBB_finish(&cbb, NULL, &buf_len)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
goto err;
}
int write_ret =
dtls1_write_record(ssl, SSL3_RT_HANDSHAKE, buf, buf_len, use_epoch);
if (write_ret <= 0) {
ret = write_ret;
goto err;
}
if (!CBS_skip(&body, todo)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
goto err;
}
offset += todo;
} while (CBS_len(&body) != 0);
ssl_do_msg_callback(ssl, 1 /* write */, ssl->version, SSL3_RT_HANDSHAKE, in,
len);
ret = 1;
err:
*out_offset = offset;
CBB_cleanup(&cbb);
OPENSSL_free(buf);
return ret;
}
void dtls_clear_outgoing_messages(SSL *ssl) {
size_t i;
for (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;
}
/* dtls1_add_change_cipher_spec adds a ChangeCipherSpec to the current
* handshake flight. */
static int dtls1_add_change_cipher_spec(SSL *ssl) {
if (ssl->d1->outgoing_messages_len >= SSL_MAX_HANDSHAKE_FLIGHT) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return 0;
}
DTLS_OUTGOING_MESSAGE *msg =
&ssl->d1->outgoing_messages[ssl->d1->outgoing_messages_len];
msg->data = NULL;
msg->len = 0;
msg->epoch = ssl->d1->w_epoch;
msg->is_ccs = 1;
ssl->d1->outgoing_messages_len++;
return 1;
}
static int dtls1_add_message(SSL *ssl, uint8_t *data, size_t len) {
if (ssl->d1->outgoing_messages_len >= SSL_MAX_HANDSHAKE_FLIGHT) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
OPENSSL_free(data);
return 0;
}
DTLS_OUTGOING_MESSAGE *msg =
&ssl->d1->outgoing_messages[ssl->d1->outgoing_messages_len];
msg->data = data;
msg->len = len;
msg->epoch = ssl->d1->w_epoch;
msg->is_ccs = 0;
ssl->d1->outgoing_messages_len++;
return 1;
}
int 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 0;
}
return 1;
}
int dtls1_finish_message(SSL *ssl, CBB *cbb) {
uint8_t *msg = NULL;
size_t len;
if (!CBB_finish(cbb, &msg, &len) ||
len > 0xffffffffu ||
len < DTLS1_HM_HEADER_LENGTH) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
OPENSSL_free(msg);
return 0;
}
/* Fix up the header. Copy the fragment length into the total message
* length. */
memcpy(msg + 1, msg + DTLS1_HM_HEADER_LENGTH - 3, 3);
ssl3_update_handshake_hash(ssl, msg, len);
ssl->d1->handshake_write_seq++;
ssl->init_off = 0;
return dtls1_add_message(ssl, msg, len);
}
int dtls1_write_message(SSL *ssl) {
if (ssl->d1->outgoing_messages_len == 0) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
const DTLS_OUTGOING_MESSAGE *msg =
&ssl->d1->outgoing_messages[ssl->d1->outgoing_messages_len - 1];
if (msg->is_ccs) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
size_t offset = ssl->init_off;
int ret = dtls1_do_handshake_write(ssl, &offset, msg->data, offset, msg->len,
dtls1_use_current_epoch);
ssl->init_off = offset;
return ret;
}
static int dtls1_retransmit_message(SSL *ssl,
const DTLS_OUTGOING_MESSAGE *msg) {
/* DTLS renegotiation is unsupported, so only epochs 0 (NULL cipher) and 1
* (negotiated cipher) exist. */
assert(ssl->d1->w_epoch == 0 || ssl->d1->w_epoch == 1);
assert(msg->epoch <= ssl->d1->w_epoch);
enum dtls1_use_epoch_t use_epoch = dtls1_use_current_epoch;
if (ssl->d1->w_epoch == 1 && msg->epoch == 0) {
use_epoch = dtls1_use_previous_epoch;
}
/* TODO(davidben): This cannot handle non-blocking writes. */
int ret;
if (msg->is_ccs) {
ret = dtls1_write_change_cipher_spec(ssl, use_epoch);
} else {
size_t offset = 0;
ret = dtls1_do_handshake_write(ssl, &offset, msg->data, offset, msg->len,
use_epoch);
}
return ret;
}
int dtls1_retransmit_outgoing_messages(SSL *ssl) {
/* Ensure we are packing handshake messages. */
const int was_buffered = ssl_is_wbio_buffered(ssl);
assert(was_buffered == SSL_in_init(ssl));
if (!was_buffered && !ssl_init_wbio_buffer(ssl)) {
return -1;
}
assert(ssl_is_wbio_buffered(ssl));
int ret = -1;
size_t i;
for (i = 0; i < ssl->d1->outgoing_messages_len; i++) {
if (dtls1_retransmit_message(ssl, &ssl->d1->outgoing_messages[i]) <= 0) {
goto err;
}
}
ret = BIO_flush(ssl->wbio);
if (ret <= 0) {
ssl->rwstate = SSL_WRITING;
goto err;
}
err:
if (!was_buffered) {
ssl_free_wbio_buffer(ssl);
}
return ret;
}
int dtls1_send_change_cipher_spec(SSL *ssl) {
int ret = dtls1_write_change_cipher_spec(ssl, dtls1_use_current_epoch);
if (ret <= 0) {
return ret;
}
dtls1_add_change_cipher_spec(ssl);
return 1;
}
unsigned int dtls1_min_mtu(void) {
return kMinMTU;
}
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