/* 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 <string.h>
#include <openssl/bio.h>
#include <openssl/buf.h>
#include <openssl/bytestring.h>
#include <openssl/mem.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#include "../crypto/internal.h"
#include "internal.h"
int dtls1_get_record(SSL *ssl) {
again:
switch (ssl->s3->recv_shutdown) {
case ssl_shutdown_none:
break;
case ssl_shutdown_fatal_alert:
OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN);
return -1;
case ssl_shutdown_close_notify:
return 0;
}
/* Read a new packet if there is no unconsumed one. */
if (ssl_read_buffer_len(ssl) == 0) {
int read_ret = ssl_read_buffer_extend_to(ssl, 0 /* unused */);
if (read_ret < 0 && dtls1_is_timer_expired(ssl)) {
/* Historically, timeouts were handled implicitly if the caller did not
* handle them.
*
* TODO(davidben): This was to support blocking sockets but affected
* non-blocking sockets. Can it be removed? */
int timeout_ret = DTLSv1_handle_timeout(ssl);
if (timeout_ret <= 0) {
return timeout_ret;
}
goto again;
}
if (read_ret <= 0) {
return read_ret;
}
}
assert(ssl_read_buffer_len(ssl) > 0);
CBS body;
uint8_t type, alert;
size_t consumed;
enum ssl_open_record_t open_ret =
dtls_open_record(ssl, &type, &body, &consumed, &alert,
ssl_read_buffer(ssl), ssl_read_buffer_len(ssl));
ssl_read_buffer_consume(ssl, consumed);
switch (open_ret) {
case ssl_open_record_partial:
/* Impossible in DTLS. */
break;
case ssl_open_record_success:
if (CBS_len(&body) > 0xffff) {
OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
return -1;
}
SSL3_RECORD *rr = &ssl->s3->rrec;
rr->type = type;
rr->length = (uint16_t)CBS_len(&body);
rr->data = (uint8_t *)CBS_data(&body);
return 1;
case ssl_open_record_discard:
goto again;
case ssl_open_record_close_notify:
return 0;
case ssl_open_record_fatal_alert:
return -1;
case ssl_open_record_error:
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return -1;
}
assert(0);
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
int dtls1_read_app_data(SSL *ssl, int *out_got_handshake, uint8_t *buf, int len,
int peek) {
assert(!SSL_in_init(ssl));
*out_got_handshake = 0;
SSL3_RECORD *rr = &ssl->s3->rrec;
again:
if (rr->length == 0) {
int ret = dtls1_get_record(ssl);
if (ret <= 0) {
return ret;
}
}
if (rr->type == SSL3_RT_HANDSHAKE) {
/* 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. */
CBS cbs, body;
struct hm_header_st msg_hdr;
CBS_init(&cbs, rr->data, rr->length);
if (!dtls1_parse_fragment(&cbs, &msg_hdr, &body)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_HANDSHAKE_RECORD);
return -1;
}
if (msg_hdr.type == SSL3_MT_FINISHED &&
msg_hdr.seq == ssl->d1->handshake_read_seq - 1) {
if (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. */
if (dtls1_check_timeout_num(ssl) < 0) {
return -1;
}
dtls1_retransmit_outgoing_messages(ssl);
}
rr->length = 0;
goto again;
}
/* Otherwise, this is a pre-CCS handshake message from an unsupported
* renegotiation attempt. Fall through to the error path. */
}
if (rr->type != SSL3_RT_APPLICATION_DATA) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
return -1;
}
/* Discard empty records. */
if (rr->length == 0) {
goto again;
}
if (len <= 0) {
return len;
}
if ((unsigned)len > rr->length) {
len = rr->length;
}
OPENSSL_memcpy(buf, rr->data, len);
if (!peek) {
/* TODO(davidben): Should the record be truncated instead? This is a
* datagram transport. See https://crbug.com/boringssl/65. */
rr->length -= len;
rr->data += len;
if (rr->length == 0) {
/* The record has been consumed, so we may now clear the buffer. */
ssl_read_buffer_discard(ssl);
}
}
return len;
}
int dtls1_read_change_cipher_spec(SSL *ssl) {
SSL3_RECORD *rr = &ssl->s3->rrec;
again:
if (rr->length == 0) {
int ret = dtls1_get_record(ssl);
if (ret <= 0) {
return ret;
}
}
/* Drop handshake records silently. The epochs match, so this must be a
* retransmit of a message we already received. */
if (rr->type == SSL3_RT_HANDSHAKE) {
rr->length = 0;
goto again;
}
/* Other record types are illegal in this epoch. Note all application data
* records come in the encrypted epoch. */
if (rr->type != SSL3_RT_CHANGE_CIPHER_SPEC) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
return -1;
}
if (rr->length != 1 || rr->data[0] != SSL3_MT_CCS) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_CHANGE_CIPHER_SPEC);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return -1;
}
ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data,
rr->length);
rr->length = 0;
ssl_read_buffer_discard(ssl);
return 1;
}
void dtls1_read_close_notify(SSL *ssl) {
/* Bidirectional shutdown doesn't make sense for an unordered transport. DTLS
* alerts also aren't delivered reliably, so we may even time out because the
* peer never received our close_notify. Report to the caller that the channel
* has fully shut down. */
if (ssl->s3->recv_shutdown == ssl_shutdown_none) {
ssl->s3->recv_shutdown = ssl_shutdown_close_notify;
}
}
int dtls1_write_app_data(SSL *ssl, const uint8_t *buf, int len) {
assert(!SSL_in_init(ssl));
if (len > SSL3_RT_MAX_PLAIN_LENGTH) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DTLS_MESSAGE_TOO_BIG);
return -1;
}
if (len < 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_LENGTH);
return -1;
}
if (len == 0) {
return 0;
}
int ret = dtls1_write_record(ssl, SSL3_RT_APPLICATION_DATA, buf, (size_t)len,
dtls1_use_current_epoch);
if (ret <= 0) {
return ret;
}
return len;
}
int dtls1_write_record(SSL *ssl, int type, const uint8_t *buf, size_t len,
enum dtls1_use_epoch_t use_epoch) {
assert(len <= 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(!ssl_write_buffer_is_pending(ssl));
if (len > SSL3_RT_MAX_PLAIN_LENGTH) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
size_t max_out = len + SSL_max_seal_overhead(ssl);
uint8_t *out;
size_t ciphertext_len;
if (!ssl_write_buffer_init(ssl, &out, max_out) ||
!dtls_seal_record(ssl, out, &ciphertext_len, max_out, type, buf, len,
use_epoch)) {
ssl_write_buffer_clear(ssl);
return -1;
}
ssl_write_buffer_set_len(ssl, 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[0], 2,
dtls1_use_current_epoch);
if (ret <= 0) {
return ret;
}
ssl->s3->alert_dispatch = 0;
/* If the alert is fatal, flush the BIO now. */
if (ssl->s3->send_alert[0] == SSL3_AL_FATAL) {
BIO_flush(ssl->wbio);
}
ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_ALERT, ssl->s3->send_alert,
2);
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;
}