/src/libressl/ssl/ssl_pkt.c

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/* $OpenBSD: ssl_pkt.c,v 1.58 2022/03/26 15:05:53 jsing 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 <stdio.h>

#include <openssl/buffer.h>
#include <openssl/evp.h>

#include "bytestring.h"
#include "dtls_locl.h"
#include "ssl_locl.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->internal->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->internal->packet and s->internal->packet_length.
 * (If s->internal->read_ahead is set, 'max' bytes may be stored in rbuf
 * [plus s->internal->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;

  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->internal->packet = rb->buf + rb->offset;
    s->internal->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->internal->packet_length += n;
    rb->left = left - n;
    rb->offset += n;
    return (n);
  }

  /* else we need to read more data */

  len = s->internal->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->internal->packet != pkt)  {
    /* len > 0 */
    memmove(pkt, s->internal->packet, len + left);
    s->internal->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->internal->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->internal->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->internal->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->internal->packet_length += n;
  s->internal->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->internal->packet_length < plen)
    return s->internal->packet_length;

  return plen;
}

int
ssl3_packet_extend(SSL *s, int plen)
{
  int rlen, n;

  if (s->internal->packet_length >= plen)
    return plen;
  rlen = plen - s->internal->packet_length;

  n = ssl3_read_n(s, rlen, rlen, 1);
  if (n <= 0)
    return n;
  if (s->internal->packet_length < plen)
    return s->internal->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->internal->rrec.type    - is the type of record
 * ssl->s3->internal->rrec.data,   - data
 * ssl->s3->internal->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;
  uint8_t *out;
  size_t out_len;
  int al, n;
  int ret = -1;

 again:
  /* check if we have the header */
  if ((s->internal->rstate != SSL_ST_READ_BODY) ||
      (s->internal->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->internal->mac_packet = 1;
    s->internal->rstate = SSL_ST_READ_BODY;

    if (s->server && s->internal->first_packet) {
      if ((ret = ssl_server_legacy_first_packet(s)) != 1)
        return (ret);
      ret = -1;
    }

    CBS_init(&header, s->internal->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->internal->first_packet && ssl_version != s->version) {
      if ((s->version & 0xFF00) == (ssl_version & 0xFF00) &&
          !tls12_record_layer_write_protected(s->internal->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->internal->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->internal->rl, s->version);

  if (!tls12_record_layer_open_record(s->internal->rl, s->internal->packet,
      s->internal->packet_length, &out, &out_len)) {
    tls12_record_layer_alert(s->internal->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;
  }

  rr->data = out;
  rr->length = out_len;
  rr->off = 0;

  /* we have pulled in a full packet so zero things */
  s->internal->packet_length = 0;

  if (rr->length == 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;
    }

    /*
     * 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->internal->empty_record_count++ > SSL_MAX_EMPTY_RECORDS) {
      SSLerror(s, SSL_R_PEER_BEHAVING_BADLY);
      return -1;
    }
    if (s->internal->empty_record_count > 1) {
      ssl_force_want_read(s);
      return -1;
    }
    goto again;
  }

  s->internal->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->internal->rwstate = SSL_NOTHING;
  tot = s->s3->wnum;
  s->s3->wnum = 0;

  if (SSL_in_init(s) && !s->internal->in_handshake) {
    i = s->internal->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->internal->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;
  uint16_t version;
  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;

  /*
   * Some servers hang if initial client hello is larger than 256
   * bytes and record version number > TLS 1.0.
   */
  version = s->version;
  if (s->s3->hs.state == SSL3_ST_CW_CLNT_HELLO_B &&
      !s->internal->renegotiate &&
      s->s3->hs.our_max_tls_version > TLS1_VERSION)
    version = TLS1_VERSION;

  /*
   * 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->internal->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->internal->rl, version);

  if (need_empty_fragment) {
    if (!tls12_record_layer_seal_record(s->internal->rl, type,
        buf, 0, &cbb))
      goto err;
    s->s3->empty_fragment_done = 1;
  }

  if (!tls12_record_layer_seal_record(s->internal->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->internal->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->internal->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->internal->mode & SSL_MODE_RELEASE_BUFFERS &&
          !SSL_is_dtls(s))
        ssl3_release_write_buffer(s);
      s->internal->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;
  }
}

int
ssl3_read_alert(SSL *s)
{
  SSL3_RECORD_INTERNAL *rr = &s->s3->rrec;
  uint8_t alert_level, alert_descr;

  /*
   * 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.
   */
  while (rr->length > 0 &&
      s->s3->alert_fragment_len < sizeof(s->s3->alert_fragment)) {
    s->s3->alert_fragment[s->s3->alert_fragment_len++] =
        rr->data[rr->off++];
    rr->length--;
  }
  if (s->s3->alert_fragment_len < sizeof(s->s3->alert_fragment)) {
    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;
  }

  ssl_msg_callback(s, 0, SSL3_RT_ALERT, s->s3->alert_fragment, 2);

  alert_level = s->s3->alert_fragment[0];
  alert_descr = s->s3->alert_fragment[1];
  s->s3->alert_fragment_len = 0;

  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->internal->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->internal->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->internal->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)
{
  SSL3_RECORD_INTERNAL *rr = &s->s3->rrec;

  /*
   * 'Change Cipher Spec' is just a single byte, so we know exactly what
   * the record payload has to look like.
   */
  if (rr->length != 1 || rr->off != 0) {
    SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC);
    ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
    return -1;
  }
  if (rr->data[0] != SSL3_MT_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(s, 0, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1);

  /* 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.
       */
      rr->length = 0;
      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;
  }

  rr->length = 0;

  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)
{
  SSL3_RECORD_INTERNAL *rr = &s->s3->rrec;
  uint32_t hs_msg_length;
  uint8_t hs_msg_type;
  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.
   */
  while (rr->length > 0 &&
      s->s3->handshake_fragment_len < sizeof(s->s3->handshake_fragment)) {
    s->s3->handshake_fragment[s->s3->handshake_fragment_len++] =
        rr->data[rr->off++];
    rr->length--;
  }

  if (s->s3->handshake_fragment_len < sizeof(s->s3->handshake_fragment))
    return 1;

  if (s->internal->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. */
  CBS_init(&cbs, s->s3->handshake_fragment, s->s3->handshake_fragment_len);
  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;
    }

    ssl_msg_callback(s, 0, SSL3_RT_HANDSHAKE,
        s->s3->handshake_fragment, s->s3->handshake_fragment_len);

    s->s3->handshake_fragment_len = 0;

    /*
     * 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->internal->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->internal->renegotiate = 1;
    s->internal->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->internal->handshake_func(s)) < 0)
    return ret;
  if (ret == 0) {
    SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE);
    return -1;
  }

  if (!(s->internal->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)
{
  SSL3_RECORD_INTERNAL *rr;
  int rrcount = 0;
  unsigned int n;
  int ret;

  if (s->s3->rbuf.buf == NULL) {
    if (!ssl3_setup_read_buffer(s))
      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_len > 0) {
    /* Partially satisfy request from fragment storage. */
    unsigned char *src = s->s3->handshake_fragment;
    unsigned char *dst = buf;
    unsigned int k;

    /* peek == 0 */
    n = 0;
    while (len > 0 && s->s3->handshake_fragment_len > 0) {
      *dst++ = *src++;
      len--;
      s->s3->handshake_fragment_len--;
      n++;
    }
    /* move any remaining fragment bytes: */
    for (k = 0; k < s->s3->handshake_fragment_len; k++)
      s->s3->handshake_fragment[k] = *src++;
    return n;
  }

  if (SSL_in_init(s) && !s->internal->in_handshake) {
    if ((ret = s->internal->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->internal->rwstate = SSL_NOTHING;

  rr = &s->s3->rrec;

  if (rr->length == 0 || s->internal->rstate == SSL_ST_READ_BODY) {
    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 && rr->type != 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->internal->shutdown & SSL_RECEIVED_SHUTDOWN) {
    s->internal->rwstate = SSL_NOTHING;
    rr->length = 0;
    return 0;
  }

  /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
  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(s) && type == SSL3_RT_APPLICATION_DATA &&
        !tls12_record_layer_read_protected(s->internal->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 ((unsigned int)len > rr->length)
      n = rr->length;
    else
      n = (unsigned int)len;

    memcpy(buf, &rr->data[rr->off], n);
    if (!peek) {
      memset(&rr->data[rr->off], 0, n);
      rr->length -= n;
      rr->off += n;
      if (rr->length == 0) {
        s->internal->rstate = SSL_ST_READ_HEADER;
        rr->off = 0;
        if (s->internal->mode & SSL_MODE_RELEASE_BUFFERS &&
            s->s3->rbuf.left == 0)
          ssl3_release_read_buffer(s);
      }
    }

    return n;
  }

  /*
   * If we get here, then type != rr->type; if we have a handshake
   * message, then it was unexpected (Hello Request or Client Hello).
   */

  if (rr->type == SSL3_RT_ALERT) {
    if ((ret = ssl3_read_alert(s)) <= 0)
      return ret;
    goto start;
  }

  if (s->internal->shutdown & SSL_SENT_SHUTDOWN) {
    s->internal->rwstate = SSL_NOTHING;
    rr->length = 0;
    return 0;
  }

  if (rr->type == 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 (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
    if ((ret = ssl3_read_change_cipher_spec(s)) <= 0)
      return ret;
    goto start;
  }

  if (rr->type == 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) {
    rr->length = 0;
    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;
}

Coverage Report

Created: 2022-08-24 06:31