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/* $OpenBSD: ssl_pkt.c,v 1.66 2023/07/11 17:02:47 tb Exp $ */
/* 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.]
*/
/* ====================================================================
* Copyright (c) 1998-2002 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).
*
*/
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <openssl/buffer.h>
#include <openssl/evp.h>
#include "bytestring.h"
#include "dtls_local.h"
#include "ssl_local.h"
#include "tls_content.h"
static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
unsigned int len);
static int ssl3_get_record(SSL *s);
/*
* Force a WANT_READ return for certain error conditions where
* we don't want to spin internally.
*/
void
ssl_force_want_read(SSL *s)
{
BIO *bio;
bio = SSL_get_rbio(s);
BIO_clear_retry_flags(bio);
BIO_set_retry_read(bio);
s->rwstate = SSL_READING;
}
/*
* If extend == 0, obtain new n-byte packet; if extend == 1, increase
* packet by another n bytes.
* The packet will be in the sub-array of s->s3->rbuf.buf specified
* by s->packet and s->packet_length.
* (If s->read_ahead is set, 'max' bytes may be stored in rbuf
* [plus s->packet_length bytes if extend == 1].)
*/
static int
ssl3_read_n(SSL *s, int n, int max, int extend)
{
SSL3_BUFFER_INTERNAL *rb = &(s->s3->rbuf);
int i, len, left;
size_t align;
unsigned char *pkt;
if (n <= 0)
return n;
if (rb->buf == NULL) {
if (!ssl3_setup_read_buffer(s))
return -1;
}
if (rb->buf == NULL)
return -1;
left = rb->left;
align = (size_t)rb->buf + SSL3_RT_HEADER_LENGTH;
align = (-align) & (SSL3_ALIGN_PAYLOAD - 1);
if (!extend) {
/* start with empty packet ... */
if (left == 0)
rb->offset = align;
else if (align != 0 && left >= SSL3_RT_HEADER_LENGTH) {
/* check if next packet length is large
* enough to justify payload alignment... */
pkt = rb->buf + rb->offset;
if (pkt[0] == SSL3_RT_APPLICATION_DATA &&
(pkt[3]<<8|pkt[4]) >= 128) {
/* Note that even if packet is corrupted
* and its length field is insane, we can
* only be led to wrong decision about
* whether memmove will occur or not.
* Header values has no effect on memmove
* arguments and therefore no buffer
* overrun can be triggered. */
memmove(rb->buf + align, pkt, left);
rb->offset = align;
}
}
s->packet = rb->buf + rb->offset;
s->packet_length = 0;
/* ... now we can act as if 'extend' was set */
}
/* For DTLS/UDP reads should not span multiple packets
* because the read operation returns the whole packet
* at once (as long as it fits into the buffer). */
if (SSL_is_dtls(s)) {
if (left > 0 && n > left)
n = left;
}
/* if there is enough in the buffer from a previous read, take some */
if (left >= n) {
s->packet_length += n;
rb->left = left - n;
rb->offset += n;
return (n);
}
/* else we need to read more data */
len = s->packet_length;
pkt = rb->buf + align;
/* Move any available bytes to front of buffer:
* 'len' bytes already pointed to by 'packet',
* 'left' extra ones at the end */
if (s->packet != pkt) {
/* len > 0 */
memmove(pkt, s->packet, len + left);
s->packet = pkt;
rb->offset = len + align;
}
if (n > (int)(rb->len - rb->offset)) {
/* does not happen */
SSLerror(s, ERR_R_INTERNAL_ERROR);
return -1;
}
if (s->read_ahead || SSL_is_dtls(s)) {
if (max < n)
max = n;
if (max > (int)(rb->len - rb->offset))
max = rb->len - rb->offset;
} else {
/* ignore max parameter */
max = n;
}
while (left < n) {
/* Now we have len+left bytes at the front of s->s3->rbuf.buf
* and need to read in more until we have len+n (up to
* len+max if possible) */
errno = 0;
if (s->rbio != NULL) {
s->rwstate = SSL_READING;
i = BIO_read(s->rbio, pkt + len + left, max - left);
} else {
SSLerror(s, SSL_R_READ_BIO_NOT_SET);
i = -1;
}
if (i <= 0) {
rb->left = left;
if (s->mode & SSL_MODE_RELEASE_BUFFERS &&
!SSL_is_dtls(s)) {
if (len + left == 0)
ssl3_release_read_buffer(s);
}
return (i);
}
left += i;
/*
* reads should *never* span multiple packets for DTLS because
* the underlying transport protocol is message oriented as
* opposed to byte oriented as in the TLS case.
*/
if (SSL_is_dtls(s)) {
if (n > left)
n = left; /* makes the while condition false */
}
}
/* done reading, now the book-keeping */
rb->offset += n;
rb->left = left - n;
s->packet_length += n;
s->rwstate = SSL_NOTHING;
return (n);
}
int
ssl3_packet_read(SSL *s, int plen)
{
int n;
n = ssl3_read_n(s, plen, s->s3->rbuf.len, 0);
if (n <= 0)
return n;
if (s->packet_length < plen)
return s->packet_length;
return plen;
}
int
ssl3_packet_extend(SSL *s, int plen)
{
int rlen, n;
if (s->packet_length >= plen)
return plen;
rlen = plen - s->packet_length;
n = ssl3_read_n(s, rlen, rlen, 1);
if (n <= 0)
return n;
if (s->packet_length < plen)
return s->packet_length;
return plen;
}
/* Call this to get a new input record.
* It will return <= 0 if more data is needed, normally due to an error
* or non-blocking IO.
* When it finishes, one packet has been decoded and can be found in
* ssl->s3->rrec.type - is the type of record
* ssl->s3->rrec.data, - data
* ssl->s3->rrec.length, - number of bytes
*/
/* used only by ssl3_read_bytes */
static int
ssl3_get_record(SSL *s)
{
SSL3_BUFFER_INTERNAL *rb = &(s->s3->rbuf);
SSL3_RECORD_INTERNAL *rr = &(s->s3->rrec);
uint8_t alert_desc;
int al, n;
int ret = -1;
again:
/* check if we have the header */
if ((s->rstate != SSL_ST_READ_BODY) ||
(s->packet_length < SSL3_RT_HEADER_LENGTH)) {
CBS header;
uint16_t len, ssl_version;
uint8_t type;
n = ssl3_packet_read(s, SSL3_RT_HEADER_LENGTH);
if (n <= 0)
return (n);
s->mac_packet = 1;
s->rstate = SSL_ST_READ_BODY;
if (s->server && s->first_packet) {
if ((ret = ssl_server_legacy_first_packet(s)) != 1)
return (ret);
ret = -1;
}
CBS_init(&header, s->packet, SSL3_RT_HEADER_LENGTH);
/* Pull apart the header into the SSL3_RECORD_INTERNAL */
if (!CBS_get_u8(&header, &type) ||
!CBS_get_u16(&header, &ssl_version) ||
!CBS_get_u16(&header, &len)) {
SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
goto err;
}
rr->type = type;
rr->length = len;
/* Lets check version */
if (!s->first_packet && ssl_version != s->version) {
if ((s->version & 0xFF00) == (ssl_version & 0xFF00) &&
!tls12_record_layer_write_protected(s->rl)) {
/* Send back error using their minor version number :-) */
s->version = ssl_version;
}
SSLerror(s, SSL_R_WRONG_VERSION_NUMBER);
al = SSL_AD_PROTOCOL_VERSION;
goto fatal_err;
}
if ((ssl_version >> 8) != SSL3_VERSION_MAJOR) {
SSLerror(s, SSL_R_WRONG_VERSION_NUMBER);
goto err;
}
if (rr->length > rb->len - SSL3_RT_HEADER_LENGTH) {
al = SSL_AD_RECORD_OVERFLOW;
SSLerror(s, SSL_R_PACKET_LENGTH_TOO_LONG);
goto fatal_err;
}
}
n = ssl3_packet_extend(s, SSL3_RT_HEADER_LENGTH + rr->length);
if (n <= 0)
return (n);
if (n != SSL3_RT_HEADER_LENGTH + rr->length)
return (n);
s->rstate = SSL_ST_READ_HEADER; /* set state for later operations */
/*
* A full record has now been read from the wire, which now needs
* to be processed.
*/
tls12_record_layer_set_version(s->rl, s->version);
if (!tls12_record_layer_open_record(s->rl, s->packet, s->packet_length,
s->s3->rcontent)) {
tls12_record_layer_alert(s->rl, &alert_desc);
if (alert_desc == 0)
goto err;
if (alert_desc == SSL_AD_RECORD_OVERFLOW)
SSLerror(s, SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
else if (alert_desc == SSL_AD_BAD_RECORD_MAC)
SSLerror(s, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
al = alert_desc;
goto fatal_err;
}
/* we have pulled in a full packet so zero things */
s->packet_length = 0;
if (tls_content_remaining(s->s3->rcontent) == 0) {
/*
* Zero-length fragments are only permitted for application
* data, as per RFC 5246 section 6.2.1.
*/
if (rr->type != SSL3_RT_APPLICATION_DATA) {
SSLerror(s, SSL_R_BAD_LENGTH);
al = SSL_AD_UNEXPECTED_MESSAGE;
goto fatal_err;
}
tls_content_clear(s->s3->rcontent);
/*
* CBC countermeasures for known IV weaknesses can legitimately
* insert a single empty record, so we allow ourselves to read
* once past a single empty record without forcing want_read.
*/
if (s->empty_record_count++ > SSL_MAX_EMPTY_RECORDS) {
SSLerror(s, SSL_R_PEER_BEHAVING_BADLY);
return -1;
}
if (s->empty_record_count > 1) {
ssl_force_want_read(s);
return -1;
}
goto again;
}
s->empty_record_count = 0;
return (1);
fatal_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
err:
return (ret);
}
/* 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
ssl3_write_bytes(SSL *s, int type, const void *buf_, int len)
{
const unsigned char *buf = buf_;
unsigned int tot, n, nw;
int i;
if (len < 0) {
SSLerror(s, ERR_R_INTERNAL_ERROR);
return -1;
}
s->rwstate = SSL_NOTHING;
tot = s->s3->wnum;
s->s3->wnum = 0;
if (SSL_in_init(s) && !s->in_handshake) {
i = s->handshake_func(s);
if (i < 0)
return (i);
if (i == 0) {
SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
}
if (len < tot)
len = tot;
n = (len - tot);
for (;;) {
if (n > s->max_send_fragment)
nw = s->max_send_fragment;
else
nw = n;
i = do_ssl3_write(s, type, &(buf[tot]), nw);
if (i <= 0) {
s->s3->wnum = tot;
return i;
}
if ((i == (int)n) || (type == SSL3_RT_APPLICATION_DATA &&
(s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE))) {
/*
* Next chunk of data should get another prepended
* empty fragment in ciphersuites with known-IV
* weakness.
*/
s->s3->empty_fragment_done = 0;
return tot + i;
}
n -= i;
tot += i;
}
}
static int
do_ssl3_write(SSL *s, int type, const unsigned char *buf, unsigned int len)
{
SSL3_BUFFER_INTERNAL *wb = &(s->s3->wbuf);
SSL_SESSION *sess = s->session;
int need_empty_fragment = 0;
size_t align, out_len;
CBB cbb;
int ret;
memset(&cbb, 0, sizeof(cbb));
if (wb->buf == NULL)
if (!ssl3_setup_write_buffer(s))
return -1;
/*
* First check if there is a SSL3_BUFFER_INTERNAL still being written
* out. This will happen with non blocking IO.
*/
if (wb->left != 0)
return (ssl3_write_pending(s, type, buf, len));
/* If we have an alert to send, let's send it. */
if (s->s3->alert_dispatch) {
if ((ret = ssl3_dispatch_alert(s)) <= 0)
return (ret);
/* If it went, fall through and send more stuff. */
/* We may have released our buffer, if so get it again. */
if (wb->buf == NULL)
if (!ssl3_setup_write_buffer(s))
return -1;
}
if (len == 0)
return 0;
/*
* Countermeasure against known-IV weakness in CBC ciphersuites
* (see http://www.openssl.org/~bodo/tls-cbc.txt). Note that this
* is unnecessary for AEAD.
*/
if (sess != NULL && tls12_record_layer_write_protected(s->rl)) {
if (s->s3->need_empty_fragments &&
!s->s3->empty_fragment_done &&
type == SSL3_RT_APPLICATION_DATA)
need_empty_fragment = 1;
}
/*
* An extra fragment would be a couple of cipher blocks, which would
* be a multiple of SSL3_ALIGN_PAYLOAD, so if we want to align the real
* payload, then we can just simply pretend we have two headers.
*/
align = (size_t)wb->buf + SSL3_RT_HEADER_LENGTH;
if (need_empty_fragment)
align += SSL3_RT_HEADER_LENGTH;
align = (-align) & (SSL3_ALIGN_PAYLOAD - 1);
wb->offset = align;
if (!CBB_init_fixed(&cbb, wb->buf + align, wb->len - align))
goto err;
tls12_record_layer_set_version(s->rl, s->version);
if (need_empty_fragment) {
if (!tls12_record_layer_seal_record(s->rl, type,
buf, 0, &cbb))
goto err;
s->s3->empty_fragment_done = 1;
}
if (!tls12_record_layer_seal_record(s->rl, type, buf, len, &cbb))
goto err;
if (!CBB_finish(&cbb, NULL, &out_len))
goto err;
wb->left = out_len;
/*
* Memorize arguments so that ssl3_write_pending can detect
* bad write retries later.
*/
s->s3->wpend_tot = len;
s->s3->wpend_buf = buf;
s->s3->wpend_type = type;
s->s3->wpend_ret = len;
/* We now just need to write the buffer. */
return ssl3_write_pending(s, type, buf, len);
err:
CBB_cleanup(&cbb);
return -1;
}
/* if s->s3->wbuf.left != 0, we need to call this */
int
ssl3_write_pending(SSL *s, int type, const unsigned char *buf, unsigned int len)
{
int i;
SSL3_BUFFER_INTERNAL *wb = &(s->s3->wbuf);
/* XXXX */
if ((s->s3->wpend_tot > (int)len) || ((s->s3->wpend_buf != buf) &&
!(s->mode & SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER)) ||
(s->s3->wpend_type != type)) {
SSLerror(s, SSL_R_BAD_WRITE_RETRY);
return (-1);
}
for (;;) {
errno = 0;
if (s->wbio != NULL) {
s->rwstate = SSL_WRITING;
i = BIO_write(s->wbio, (char *)&(wb->buf[wb->offset]),
(unsigned int)wb->left);
} else {
SSLerror(s, SSL_R_BIO_NOT_SET);
i = -1;
}
if (i == wb->left) {
wb->left = 0;
wb->offset += i;
if (s->mode & SSL_MODE_RELEASE_BUFFERS &&
!SSL_is_dtls(s))
ssl3_release_write_buffer(s);
s->rwstate = SSL_NOTHING;
return (s->s3->wpend_ret);
} else if (i <= 0) {
/*
* For DTLS, just drop it. That's kind of the
* whole point in using a datagram service.
*/
if (SSL_is_dtls(s))
wb->left = 0;
return (i);
}
wb->offset += i;
wb->left -= i;
}
}
static ssize_t
ssl3_read_cb(void *buf, size_t n, void *cb_arg)
{
SSL *s = cb_arg;
return tls_content_read(s->s3->rcontent, buf, n);
}
#define SSL3_ALERT_LENGTH 2
int
ssl3_read_alert(SSL *s)
{
uint8_t alert_level, alert_descr;
ssize_t ret;
CBS cbs;
/*
* TLSv1.2 permits an alert to be fragmented across multiple records or
* for multiple alerts to be be coalesced into a single alert record.
* In the case of DTLS, there is no way to reassemble an alert
* fragmented across multiple records, hence a full alert must be
* available in the record.
*/
if (s->s3->alert_fragment == NULL) {
if ((s->s3->alert_fragment = tls_buffer_new(0)) == NULL)
return -1;
tls_buffer_set_capacity_limit(s->s3->alert_fragment,
SSL3_ALERT_LENGTH);
}
ret = tls_buffer_extend(s->s3->alert_fragment, SSL3_ALERT_LENGTH,
ssl3_read_cb, s);
if (ret <= 0 && ret != TLS_IO_WANT_POLLIN)
return -1;
if (ret != SSL3_ALERT_LENGTH) {
if (SSL_is_dtls(s)) {
SSLerror(s, SSL_R_BAD_LENGTH);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return -1;
}
return 1;
}
if (!tls_buffer_data(s->s3->alert_fragment, &cbs))
return -1;
ssl_msg_callback_cbs(s, 0, SSL3_RT_ALERT, &cbs);
if (!CBS_get_u8(&cbs, &alert_level))
return -1;
if (!CBS_get_u8(&cbs, &alert_descr))
return -1;
tls_buffer_free(s->s3->alert_fragment);
s->s3->alert_fragment = NULL;
ssl_info_callback(s, SSL_CB_READ_ALERT,
(alert_level << 8) | alert_descr);
if (alert_level == SSL3_AL_WARNING) {
s->s3->warn_alert = alert_descr;
if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
s->shutdown |= SSL_RECEIVED_SHUTDOWN;
return 0;
}
/* We requested renegotiation and the peer rejected it. */
if (alert_descr == SSL_AD_NO_RENEGOTIATION) {
SSLerror(s, SSL_R_NO_RENEGOTIATION);
ssl3_send_alert(s, SSL3_AL_FATAL,
SSL_AD_HANDSHAKE_FAILURE);
return -1;
}
} else if (alert_level == SSL3_AL_FATAL) {
s->rwstate = SSL_NOTHING;
s->s3->fatal_alert = alert_descr;
SSLerror(s, SSL_AD_REASON_OFFSET + alert_descr);
ERR_asprintf_error_data("SSL alert number %d", alert_descr);
s->shutdown |= SSL_RECEIVED_SHUTDOWN;
SSL_CTX_remove_session(s->ctx, s->session);
return 0;
} else {
SSLerror(s, SSL_R_UNKNOWN_ALERT_TYPE);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return -1;
}
return 1;
}
int
ssl3_read_change_cipher_spec(SSL *s)
{
const uint8_t ccs[1] = { SSL3_MT_CCS };
/*
* 'Change Cipher Spec' is just a single byte, so we know exactly what
* the record payload has to look like.
*/
if (tls_content_remaining(s->s3->rcontent) != sizeof(ccs)) {
SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return -1;
}
if (!tls_content_equal(s->s3->rcontent, ccs, sizeof(ccs))) {
SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return -1;
}
/* XDTLS: check that epoch is consistent */
ssl_msg_callback_cbs(s, 0, SSL3_RT_CHANGE_CIPHER_SPEC,
tls_content_cbs(s->s3->rcontent));
/* Check that we have a cipher to change to. */
if (s->s3->hs.cipher == NULL) {
SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
/* Check that we should be receiving a Change Cipher Spec. */
if (SSL_is_dtls(s)) {
if (!s->d1->change_cipher_spec_ok) {
/*
* We can't process a CCS now, because previous
* handshake messages are still missing, so just
* drop it.
*/
tls_content_clear(s->s3->rcontent);
return 1;
}
s->d1->change_cipher_spec_ok = 0;
} else {
if ((s->s3->flags & SSL3_FLAGS_CCS_OK) == 0) {
SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
ssl3_send_alert(s, SSL3_AL_FATAL,
SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
s->s3->flags &= ~SSL3_FLAGS_CCS_OK;
}
tls_content_clear(s->s3->rcontent);
s->s3->change_cipher_spec = 1;
if (!ssl3_do_change_cipher_spec(s))
return -1;
return 1;
}
static int
ssl3_read_handshake_unexpected(SSL *s)
{
uint32_t hs_msg_length;
uint8_t hs_msg_type;
ssize_t ssret;
CBS cbs;
int ret;
/*
* We need four bytes of handshake data so we have a handshake message
* header - this may be in the same record or fragmented across multiple
* records.
*/
if (s->s3->handshake_fragment == NULL) {
if ((s->s3->handshake_fragment = tls_buffer_new(0)) == NULL)
return -1;
tls_buffer_set_capacity_limit(s->s3->handshake_fragment,
SSL3_HM_HEADER_LENGTH);
}
ssret = tls_buffer_extend(s->s3->handshake_fragment, SSL3_HM_HEADER_LENGTH,
ssl3_read_cb, s);
if (ssret <= 0 && ssret != TLS_IO_WANT_POLLIN)
return -1;
if (ssret != SSL3_HM_HEADER_LENGTH)
return 1;
if (s->in_handshake) {
SSLerror(s, ERR_R_INTERNAL_ERROR);
return -1;
}
/*
* This code currently deals with HelloRequest and ClientHello messages -
* anything else is pushed to the handshake_func. Almost all of this
* belongs in the client/server handshake code.
*/
/* Parse handshake message header. */
if (!tls_buffer_data(s->s3->handshake_fragment, &cbs))
return -1;
if (!CBS_get_u8(&cbs, &hs_msg_type))
return -1;
if (!CBS_get_u24(&cbs, &hs_msg_length))
return -1;
if (hs_msg_type == SSL3_MT_HELLO_REQUEST) {
/*
* Incoming HelloRequest messages should only be received by a
* client. A server may send these at any time - a client should
* ignore the message if received in the middle of a handshake.
* See RFC 5246 sections 7.4 and 7.4.1.1.
*/
if (s->server) {
SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
ssl3_send_alert(s, SSL3_AL_FATAL,
SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
if (hs_msg_length != 0) {
SSLerror(s, SSL_R_BAD_HELLO_REQUEST);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return -1;
}
if (!tls_buffer_data(s->s3->handshake_fragment, &cbs))
return -1;
ssl_msg_callback_cbs(s, 0, SSL3_RT_HANDSHAKE, &cbs);
tls_buffer_free(s->s3->handshake_fragment);
s->s3->handshake_fragment = NULL;
/*
* It should be impossible to hit this, but keep the safety
* harness for now...
*/
if (s->session == NULL || s->session->cipher == NULL)
return 1;
/*
* Ignore this message if we're currently handshaking,
* renegotiation is already pending or renegotiation is disabled
* via flags.
*/
if (!SSL_is_init_finished(s) || s->s3->renegotiate ||
(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) != 0)
return 1;
if (!ssl3_renegotiate(s))
return 1;
if (!ssl3_renegotiate_check(s))
return 1;
} else if (hs_msg_type == SSL3_MT_CLIENT_HELLO) {
/*
* Incoming ClientHello messages should only be received by a
* server. A client may send these in response to server
* initiated renegotiation (HelloRequest) or in order to
* initiate renegotiation by the client. See RFC 5246 section
* 7.4.1.2.
*/
if (!s->server) {
SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
ssl3_send_alert(s, SSL3_AL_FATAL,
SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
/*
* A client should not be sending a ClientHello unless we're not
* currently handshaking.
*/
if (!SSL_is_init_finished(s)) {
SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
ssl3_send_alert(s, SSL3_AL_FATAL,
SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
if ((s->options & SSL_OP_NO_CLIENT_RENEGOTIATION) != 0) {
ssl3_send_alert(s, SSL3_AL_FATAL,
SSL_AD_NO_RENEGOTIATION);
return -1;
}
if (s->session == NULL || s->session->cipher == NULL) {
SSLerror(s, ERR_R_INTERNAL_ERROR);
return -1;
}
/* Client requested renegotiation but it is not permitted. */
if (!s->s3->send_connection_binding ||
(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) != 0) {
ssl3_send_alert(s, SSL3_AL_WARNING,
SSL_AD_NO_RENEGOTIATION);
return 1;
}
s->s3->hs.state = SSL_ST_ACCEPT;
s->renegotiate = 1;
s->new_session = 1;
} else {
SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
if ((ret = s->handshake_func(s)) < 0)
return ret;
if (ret == 0) {
SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
if (!(s->mode & SSL_MODE_AUTO_RETRY)) {
if (s->s3->rbuf.left == 0) {
ssl_force_want_read(s);
return -1;
}
}
/*
* We either finished a handshake or ignored the request, now try again
* to obtain the (application) data we were asked for.
*/
return 1;
}
/* Return up to 'len' payload bytes received in 'type' records.
* 'type' is one of the following:
*
* - SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
* - SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
* - 0 (during a shutdown, no data has to be returned)
*
* If we don't have stored data to work from, read a SSL/TLS 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), ChangeCipherSpec records (not really
* a surprise, but handled as if it were), or renegotiation requests.
* Also if record payloads contain fragments too small to process, we store
* them until there is enough for the respective protocol (the record protocol
* may use arbitrary fragmentation and even interleaving):
* Change cipher spec protocol
* just 1 byte needed, no need for keeping anything stored
* Alert protocol
* 2 bytes needed (AlertLevel, AlertDescription)
* Handshake protocol
* 4 bytes needed (HandshakeType, uint24 length) -- we just have
* to detect unexpected Client Hello and Hello Request messages
* here, anything else is handled by higher layers
* Application data protocol
* none of our business
*/
int
ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
{
int rrcount = 0;
ssize_t ssret;
int ret;
if (s->s3->rbuf.buf == NULL) {
if (!ssl3_setup_read_buffer(s))
return -1;
}
if (s->s3->rcontent == NULL) {
if ((s->s3->rcontent = tls_content_new()) == NULL)
return -1;
}
if (len < 0) {
SSLerror(s, ERR_R_INTERNAL_ERROR);
return -1;
}
if (type != 0 && type != SSL3_RT_APPLICATION_DATA &&
type != SSL3_RT_HANDSHAKE) {
SSLerror(s, ERR_R_INTERNAL_ERROR);
return -1;
}
if (peek && type != SSL3_RT_APPLICATION_DATA) {
SSLerror(s, ERR_R_INTERNAL_ERROR);
return -1;
}
if (type == SSL3_RT_HANDSHAKE &&
s->s3->handshake_fragment != NULL &&
tls_buffer_remaining(s->s3->handshake_fragment) > 0) {
ssize_t ssn;
if ((ssn = tls_buffer_read(s->s3->handshake_fragment, buf,
len)) <= 0)
return -1;
if (tls_buffer_remaining(s->s3->handshake_fragment) == 0) {
tls_buffer_free(s->s3->handshake_fragment);
s->s3->handshake_fragment = NULL;
}
return (int)ssn;
}
if (SSL_in_init(s) && !s->in_handshake) {
if ((ret = s->handshake_func(s)) < 0)
return ret;
if (ret == 0) {
SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
}
start:
/*
* Do not process more than three consecutive records, otherwise the
* peer can cause us to loop indefinitely. Instead, return with an
* SSL_ERROR_WANT_READ so the caller can choose when to handle further
* processing. In the future, the total number of non-handshake and
* non-application data records per connection should probably also be
* limited...
*/
if (rrcount++ >= 3) {
ssl_force_want_read(s);
return -1;
}
s->rwstate = SSL_NOTHING;
if (tls_content_remaining(s->s3->rcontent) == 0) {
if ((ret = ssl3_get_record(s)) <= 0)
return ret;
}
/* We now have a packet which can be read and processed. */
if (s->s3->change_cipher_spec &&
tls_content_type(s->s3->rcontent) != SSL3_RT_HANDSHAKE) {
SSLerror(s, SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
/*
* If the other end has shut down, throw anything we read away (even in
* 'peek' mode).
*/
if (s->shutdown & SSL_RECEIVED_SHUTDOWN) {
s->rwstate = SSL_NOTHING;
tls_content_clear(s->s3->rcontent);
s->s3->rrec.length = 0;
return 0;
}
/* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
if (tls_content_type(s->s3->rcontent) == type) {
/*
* Make sure that we are not getting application data when we
* are doing a handshake for the first time.
*/
if (SSL_in_init(s) && type == SSL3_RT_APPLICATION_DATA &&
!tls12_record_layer_read_protected(s->rl)) {
SSLerror(s, SSL_R_APP_DATA_IN_HANDSHAKE);
ssl3_send_alert(s, SSL3_AL_FATAL,
SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
if (len <= 0)
return len;
if (peek) {
ssret = tls_content_peek(s->s3->rcontent, buf, len);
} else {
ssret = tls_content_read(s->s3->rcontent, buf, len);
}
if (ssret < INT_MIN || ssret > INT_MAX)
return -1;
if (ssret < 0)
return (int)ssret;
if (tls_content_remaining(s->s3->rcontent) == 0) {
s->rstate = SSL_ST_READ_HEADER;
if (s->mode & SSL_MODE_RELEASE_BUFFERS &&
s->s3->rbuf.left == 0)
ssl3_release_read_buffer(s);
}
return ssret;
}
if (tls_content_type(s->s3->rcontent) == SSL3_RT_ALERT) {
if ((ret = ssl3_read_alert(s)) <= 0)
return ret;
goto start;
}
if (s->shutdown & SSL_SENT_SHUTDOWN) {
s->rwstate = SSL_NOTHING;
tls_content_clear(s->s3->rcontent);
s->s3->rrec.length = 0;
return 0;
}
if (tls_content_type(s->s3->rcontent) == SSL3_RT_APPLICATION_DATA) {
/*
* At this point, we were expecting handshake data, but have
* application data. If the library was running inside
* ssl3_read() (i.e. in_read_app_data is set) and it makes
* sense to read application data at this point (session
* renegotiation not yet started), we will indulge it.
*/
if (s->s3->in_read_app_data != 0 &&
s->s3->total_renegotiations != 0 &&
(((s->s3->hs.state & SSL_ST_CONNECT) &&
(s->s3->hs.state >= SSL3_ST_CW_CLNT_HELLO_A) &&
(s->s3->hs.state <= SSL3_ST_CR_SRVR_HELLO_A)) || (
(s->s3->hs.state & SSL_ST_ACCEPT) &&
(s->s3->hs.state <= SSL3_ST_SW_HELLO_REQ_A) &&
(s->s3->hs.state >= SSL3_ST_SR_CLNT_HELLO_A)))) {
s->s3->in_read_app_data = 2;
return -1;
} else {
SSLerror(s, SSL_R_UNEXPECTED_RECORD);
ssl3_send_alert(s, SSL3_AL_FATAL,
SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
}
if (tls_content_type(s->s3->rcontent) == SSL3_RT_CHANGE_CIPHER_SPEC) {
if ((ret = ssl3_read_change_cipher_spec(s)) <= 0)
return ret;
goto start;
}
if (tls_content_type(s->s3->rcontent) == SSL3_RT_HANDSHAKE) {
if ((ret = ssl3_read_handshake_unexpected(s)) <= 0)
return ret;
goto start;
}
/*
* Unknown record type - TLSv1.2 sends an unexpected message alert while
* earlier versions silently ignore the record.
*/
if (ssl_effective_tls_version(s) <= TLS1_1_VERSION) {
tls_content_clear(s->s3->rcontent);
goto start;
}
SSLerror(s, SSL_R_UNEXPECTED_RECORD);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
int
ssl3_do_change_cipher_spec(SSL *s)
{
if (s->s3->hs.tls12.key_block == NULL) {
if (s->session == NULL || s->session->master_key_length == 0) {
/* might happen if dtls1_read_bytes() calls this */
SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
return (0);
}
s->session->cipher = s->s3->hs.cipher;
if (!tls1_setup_key_block(s))
return (0);
}
if (!tls1_change_read_cipher_state(s))
return (0);
/*
* We have to record the message digest at this point so we can get it
* before we read the finished message.
*/
if (!tls12_derive_peer_finished(s))
return (0);
return (1);
}
static int
ssl3_write_alert(SSL *s)
{
if (SSL_is_dtls(s))
return do_dtls1_write(s, SSL3_RT_ALERT, s->s3->send_alert,
sizeof(s->s3->send_alert));
return do_ssl3_write(s, SSL3_RT_ALERT, s->s3->send_alert,
sizeof(s->s3->send_alert));
}
int
ssl3_send_alert(SSL *s, int level, int desc)
{
/* If alert is fatal, remove session from cache. */
if (level == SSL3_AL_FATAL)
SSL_CTX_remove_session(s->ctx, s->session);
s->s3->alert_dispatch = 1;
s->s3->send_alert[0] = level;
s->s3->send_alert[1] = desc;
/*
* If data is still being written out, the alert will be dispatched at
* some point in the future.
*/
if (s->s3->wbuf.left != 0)
return -1;
return ssl3_dispatch_alert(s);
}
int
ssl3_dispatch_alert(SSL *s)
{
int ret;
s->s3->alert_dispatch = 0;
if ((ret = ssl3_write_alert(s)) <= 0) {
s->s3->alert_dispatch = 1;
return ret;
}
/*
* Alert sent to BIO. If it is important, flush it now.
* If the message does not get sent due to non-blocking IO,
* we will not worry too much.
*/
if (s->s3->send_alert[0] == SSL3_AL_FATAL)
(void)BIO_flush(s->wbio);
ssl_msg_callback(s, 1, SSL3_RT_ALERT, s->s3->send_alert, 2);
ssl_info_callback(s, SSL_CB_WRITE_ALERT,
(s->s3->send_alert[0] << 8) | s->s3->send_alert[1]);
return ret;
}
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