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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 <string.h>
#include <openssl/buf.h>
#include <openssl/mem.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#include "internal.h"
static int do_dtls1_write(SSL *ssl, int type, const uint8_t *buf,
unsigned int len, enum dtls1_use_epoch_t use_epoch);
/* dtls1_get_record reads a new input record. On success, it places it in
* |ssl->s3->rrec| and returns one. Otherwise it returns <= 0 on error or if
* more data is needed. */
static int dtls1_get_record(SSL *ssl) {
again:
/* Read a new packet if there is no unconsumed one. */
if (ssl_read_buffer_len(ssl) == 0) {
int ret = ssl_read_buffer_extend_to(ssl, 0 /* unused */);
if (ret <= 0) {
return ret;
}
}
assert(ssl_read_buffer_len(ssl) > 0);
/* Ensure the packet is large enough to decrypt in-place. */
if (ssl_read_buffer_len(ssl) < ssl_record_prefix_len(ssl)) {
ssl_read_buffer_clear(ssl);
goto again;
}
uint8_t *out = ssl_read_buffer(ssl) + ssl_record_prefix_len(ssl);
size_t max_out = ssl_read_buffer_len(ssl) - ssl_record_prefix_len(ssl);
uint8_t type, alert;
size_t len, consumed;
switch (dtls_open_record(ssl, &type, out, &len, &consumed, &alert, max_out,
ssl_read_buffer(ssl), ssl_read_buffer_len(ssl))) {
case ssl_open_record_success:
ssl_read_buffer_consume(ssl, consumed);
if (len > 0xffff) {
OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
return -1;
}
SSL3_RECORD *rr = &ssl->s3->rrec;
rr->type = type;
rr->length = (uint16_t)len;
rr->data = out;
return 1;
case ssl_open_record_discard:
ssl_read_buffer_consume(ssl, consumed);
goto again;
case ssl_open_record_error:
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return -1;
case ssl_open_record_partial:
/* Impossible in DTLS. */
break;
}
assert(0);
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
int dtls1_read_app_data(SSL *ssl, uint8_t *buf, int len, int peek) {
assert(!SSL_in_init(ssl));
return dtls1_read_bytes(ssl, SSL3_RT_APPLICATION_DATA, buf, len, peek);
}
int dtls1_read_change_cipher_spec(SSL *ssl) {
uint8_t byte;
int ret = dtls1_read_bytes(ssl, SSL3_RT_CHANGE_CIPHER_SPEC, &byte,
1 /* len */, 0 /* no peek */);
if (ret <= 0) {
return ret;
}
assert(ret == 1);
if (ssl->s3->rrec.length != 0 || byte != 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;
}
if (ssl->msg_callback != NULL) {
ssl->msg_callback(0, ssl->version, SSL3_RT_CHANGE_CIPHER_SPEC, &byte, 1,
ssl, ssl->msg_callback_arg);
}
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. */
ssl->shutdown |= SSL_RECEIVED_SHUTDOWN;
}
/* Return up to 'len' payload bytes received in 'type' records.
* 'type' is one of the following:
*
* - SSL3_RT_HANDSHAKE (when dtls1_get_message calls us)
* - SSL3_RT_CHANGE_CIPHER_SPEC (when dtls1_read_change_cipher_spec calls us)
* - SSL3_RT_APPLICATION_DATA (when dtls1_read_app_data calls us)
*
* If we don't have stored data to work from, read a DTLS record first (possibly
* multiple records if we still don't have anything to return).
*
* This function must handle any surprises the peer may have for us, such as
* Alert records (e.g. close_notify) and out of records. */
int dtls1_read_bytes(SSL *ssl, int type, unsigned char *buf, int len, int peek) {
int al, ret;
unsigned int n;
SSL3_RECORD *rr;
void (*cb)(const SSL *ssl, int type, int value) = NULL;
if ((type != SSL3_RT_APPLICATION_DATA && type != SSL3_RT_HANDSHAKE &&
type != SSL3_RT_CHANGE_CIPHER_SPEC) ||
(peek && type != SSL3_RT_APPLICATION_DATA)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
start:
/* ssl->s3->rrec.type - is the type of record
* ssl->s3->rrec.data - data
* ssl->s3->rrec.off - offset into 'data' for next read
* ssl->s3->rrec.length - number of bytes. */
rr = &ssl->s3->rrec;
/* Check for timeout */
if (DTLSv1_handle_timeout(ssl) > 0) {
goto start;
}
/* get new packet if necessary */
if (rr->length == 0) {
ret = dtls1_get_record(ssl);
if (ret <= 0) {
ret = dtls1_read_failed(ssl, ret);
/* anything other than a timeout is an error */
if (ret <= 0) {
return ret;
} else {
goto start;
}
}
}
/* we now have a packet which can be read and processed */
/* If the other end has shut down, throw anything we read away (even in
* 'peek' mode) */
if (ssl->shutdown & SSL_RECEIVED_SHUTDOWN) {
rr->length = 0;
return 0;
}
if (type == rr->type) {
/* Make sure that we are not getting application data when we
* are doing a handshake for the first time. */
if (SSL_in_init(ssl) && (type == SSL3_RT_APPLICATION_DATA) &&
(ssl->s3->aead_read_ctx == NULL)) {
/* TODO(davidben): Is this check redundant with the handshake_func
* check? */
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, SSL_R_APP_DATA_IN_HANDSHAKE);
goto f_err;
}
/* Discard empty records. */
if (rr->length == 0) {
goto start;
}
if (len <= 0) {
return len;
}
if ((unsigned int)len > rr->length) {
n = rr->length;
} else {
n = (unsigned int)len;
}
memcpy(buf, rr->data, n);
if (!peek) {
rr->length -= n;
rr->data += n;
if (rr->length == 0) {
/* The record has been consumed, so we may now clear the buffer. */
ssl_read_buffer_discard(ssl);
}
}
return n;
}
/* If we get here, then type != rr->type. */
/* If an alert record, process the alert. */
if (rr->type == SSL3_RT_ALERT) {
/* Alerts records may not contain fragmented or multiple alerts. */
if (rr->length != 2) {
al = SSL_AD_DECODE_ERROR;
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ALERT);
goto f_err;
}
if (ssl->msg_callback) {
ssl->msg_callback(0, ssl->version, SSL3_RT_ALERT, rr->data, 2, ssl,
ssl->msg_callback_arg);
}
const uint8_t alert_level = rr->data[0];
const uint8_t alert_descr = rr->data[1];
rr->length -= 2;
rr->data += 2;
if (ssl->info_callback != NULL) {
cb = ssl->info_callback;
} else if (ssl->ctx->info_callback != NULL) {
cb = ssl->ctx->info_callback;
}
if (cb != NULL) {
uint16_t alert = (alert_level << 8) | alert_descr;
cb(ssl, SSL_CB_READ_ALERT, alert);
}
if (alert_level == SSL3_AL_WARNING) {
if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
ssl->s3->clean_shutdown = 1;
ssl->shutdown |= SSL_RECEIVED_SHUTDOWN;
return 0;
}
} else if (alert_level == SSL3_AL_FATAL) {
char tmp[16];
OPENSSL_PUT_ERROR(SSL, SSL_AD_REASON_OFFSET + alert_descr);
BIO_snprintf(tmp, sizeof tmp, "%d", alert_descr);
ERR_add_error_data(2, "SSL alert number ", tmp);
ssl->shutdown |= SSL_RECEIVED_SHUTDOWN;
SSL_CTX_remove_session(ssl->ctx, ssl->session);
return 0;
} else {
al = SSL_AD_ILLEGAL_PARAMETER;
OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_ALERT_TYPE);
goto f_err;
}
goto start;
}
/* 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) {
if (type != SSL3_RT_APPLICATION_DATA) {
/* Out-of-order handshake record while looking for ChangeCipherSpec. Drop
* it silently. */
assert(type == SSL3_RT_CHANGE_CIPHER_SPEC);
rr->length = 0;
goto start;
}
/* 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. */
if (rr->length < DTLS1_HM_HEADER_LENGTH) {
al = SSL_AD_DECODE_ERROR;
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_HANDSHAKE_RECORD);
goto f_err;
}
struct hm_header_st msg_hdr;
dtls1_get_message_header(rr->data, &msg_hdr);
if (msg_hdr.type == SSL3_MT_FINISHED) {
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_buffered_messages(ssl);
}
rr->length = 0;
goto start;
}
/* Otherwise, this is a pre-CCS handshake message from an unsupported
* renegotiation attempt. Fall through to the error path. */
}
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD);
f_err:
ssl3_send_alert(ssl, SSL3_AL_FATAL, al);
return -1;
}
int dtls1_write_app_data(SSL *ssl, const void *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;
}
return dtls1_write_bytes(ssl, SSL3_RT_APPLICATION_DATA, buf_, len,
dtls1_use_current_epoch);
}
/* Call this to write data in records of type 'type' It will return <= 0 if not
* all data has been sent or non-blocking IO. */
int dtls1_write_bytes(SSL *ssl, int type, const void *buf, int len,
enum dtls1_use_epoch_t use_epoch) {
assert(len <= SSL3_RT_MAX_PLAIN_LENGTH);
return do_dtls1_write(ssl, type, buf, len, use_epoch);
}
static int do_dtls1_write(SSL *ssl, int type, const uint8_t *buf,
unsigned int len, enum dtls1_use_epoch_t use_epoch) {
/* 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 we have an alert to send, lets send it */
if (ssl->s3->alert_dispatch) {
int ret = ssl->method->ssl_dispatch_alert(ssl);
if (ret <= 0) {
return ret;
}
/* if it went, fall through and send more stuff */
}
if (len > SSL3_RT_MAX_PLAIN_LENGTH) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
if (len == 0) {
return 0;
}
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 (int)len;
}
int dtls1_dispatch_alert(SSL *ssl) {
ssl->s3->alert_dispatch = 0;
int ret = do_dtls1_write(ssl, SSL3_RT_ALERT, &ssl->s3->send_alert[0], 2,
dtls1_use_current_epoch);
if (ret <= 0) {
ssl->s3->alert_dispatch = 1;
return ret;
}
/* If the alert is fatal, flush the BIO now. */
if (ssl->s3->send_alert[0] == SSL3_AL_FATAL) {
BIO_flush(ssl->wbio);
}
if (ssl->msg_callback != NULL) {
ssl->msg_callback(1 /* write */, ssl->version, SSL3_RT_ALERT,
ssl->s3->send_alert, 2, ssl, ssl->msg_callback_arg);
}
void (*cb)(const SSL *ssl, int type, int value) = NULL;
if (ssl->info_callback != NULL) {
cb = ssl->info_callback;
} else if (ssl->ctx->info_callback != NULL) {
cb = ssl->ctx->info_callback;
}
if (cb != NULL) {
int alert = (ssl->s3->send_alert[0] << 8) | ssl->s3->send_alert[1];
cb(ssl, SSL_CB_WRITE_ALERT, alert);
}
return 1;
}