boringssl/ssl/s3_enc.c

/* 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.
 *g
 * 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).
 *g
 * 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.
 *g
 * 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) fromg
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *g
 * 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.
 *g
 * 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) 1998-2007 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.g
 *
 * 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 2005 Nokia. All rights reserved.
 *
 * The portions of the attached software ("Contribution") is developed by
 * Nokia Corporation and is licensed pursuant to the OpenSSL open source
 * license.
 *
 * The Contribution, originally written by Mika Kousa and Pasi Eronen of
 * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
 * support (see RFC 4279) to OpenSSL.
 *
 * No patent licenses or other rights except those expressly stated in
 * the OpenSSL open source license shall be deemed granted or received
 * expressly, by implication, estoppel, or otherwise.
 *
 * No assurances are provided by Nokia that the Contribution does not
 * infringe the patent or other intellectual property rights of any third
 * party or that the license provides you with all the necessary rights
 * to make use of the Contribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
 * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
 * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
 * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
 * OTHERWISE. */

#include <stdio.h>
#include <assert.h>

#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/mem.h>
#include <openssl/md5.h>
#include <openssl/obj.h>

#include "ssl_locl.h"


static const uint8_t ssl3_pad_1[48] = {
    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
};

static const uint8_t ssl3_pad_2[48] = {
    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
};

static int ssl3_handshake_mac(SSL *s, int md_nid, const char *sender, int len,
                              uint8_t *p);

static int ssl3_generate_key_block(SSL *s, uint8_t *km, int num) {
  EVP_MD_CTX md5;
  EVP_MD_CTX sha1;
  uint8_t buf[16], smd[SHA_DIGEST_LENGTH];
  uint8_t c = 'A';
  unsigned int i, j, k;

  k = 0;
  EVP_MD_CTX_init(&md5);
  EVP_MD_CTX_init(&sha1);
  for (i = 0; (int)i < num; i += MD5_DIGEST_LENGTH) {
    k++;
    if (k > sizeof(buf)) {
      /* bug: 'buf' is too small for this ciphersuite */
      OPENSSL_PUT_ERROR(SSL, ssl3_generate_key_block, ERR_R_INTERNAL_ERROR);
      return 0;
    }

    for (j = 0; j < k; j++) {
      buf[j] = c;
    }
    c++;
    if (!EVP_DigestInit_ex(&sha1, EVP_sha1(), NULL)) {
      OPENSSL_PUT_ERROR(SSL, ssl3_generate_key_block, ERR_LIB_EVP);
      return 0;
    }
    EVP_DigestUpdate(&sha1, buf, k);
    EVP_DigestUpdate(&sha1, s->session->master_key,
                     s->session->master_key_length);
    EVP_DigestUpdate(&sha1, s->s3->server_random, SSL3_RANDOM_SIZE);
    EVP_DigestUpdate(&sha1, s->s3->client_random, SSL3_RANDOM_SIZE);
    EVP_DigestFinal_ex(&sha1, smd, NULL);

    if (!EVP_DigestInit_ex(&md5, EVP_md5(), NULL)) {
      OPENSSL_PUT_ERROR(SSL, ssl3_generate_key_block, ERR_LIB_EVP);
      return 0;
    }
    EVP_DigestUpdate(&md5, s->session->master_key,
                     s->session->master_key_length);
    EVP_DigestUpdate(&md5, smd, SHA_DIGEST_LENGTH);
    if ((int)(i + MD5_DIGEST_LENGTH) > num) {
      EVP_DigestFinal_ex(&md5, smd, NULL);
      memcpy(km, smd, (num - i));
    } else {
      EVP_DigestFinal_ex(&md5, km, NULL);
    }

    km += MD5_DIGEST_LENGTH;
  }

  OPENSSL_cleanse(smd, SHA_DIGEST_LENGTH);
  EVP_MD_CTX_cleanup(&md5);
  EVP_MD_CTX_cleanup(&sha1);

  return 1;
}

int ssl3_change_cipher_state(SSL *s, int which) {
  uint8_t *p, *mac_secret;
  uint8_t exp_key[EVP_MAX_KEY_LENGTH];
  uint8_t exp_iv[EVP_MAX_IV_LENGTH];
  uint8_t *ms, *key, *iv;
  EVP_CIPHER_CTX *dd;
  const EVP_CIPHER *c;
  const EVP_MD *m;
  int n, i, j, k, cl;
  int reuse_dd = 0;

  c = s->s3->tmp.new_sym_enc;
  m = s->s3->tmp.new_hash;
  /* m == NULL will lead to a crash later */
  assert(m);

  if (which & SSL3_CC_READ) {
    if (s->enc_read_ctx != NULL) {
      reuse_dd = 1;
    } else {
      s->enc_read_ctx = OPENSSL_malloc(sizeof(EVP_CIPHER_CTX));
      if (s->enc_read_ctx == NULL) {
        goto err;
      }
      EVP_CIPHER_CTX_init(s->enc_read_ctx);
    }
    dd = s->enc_read_ctx;

    ssl_replace_hash(&s->read_hash, m);
    memset(&s->s3->read_sequence[0], 0, 8);
    mac_secret = &s->s3->read_mac_secret[0];
  } else {
    if (s->enc_write_ctx != NULL) {
      reuse_dd = 1;
    } else {
      s->enc_write_ctx = OPENSSL_malloc(sizeof(EVP_CIPHER_CTX));
      if (s->enc_write_ctx == NULL) {
        goto err;
      }
      EVP_CIPHER_CTX_init(s->enc_write_ctx);
    }
    dd = s->enc_write_ctx;
    ssl_replace_hash(&s->write_hash, m);
    memset(&s->s3->write_sequence[0], 0, 8);
    mac_secret = &s->s3->write_mac_secret[0];
  }

  if (reuse_dd) {
    EVP_CIPHER_CTX_cleanup(dd);
  }

  p = s->s3->tmp.key_block;
  i = EVP_MD_size(m);
  cl = EVP_CIPHER_key_length(c);
  j = cl;
  k = EVP_CIPHER_iv_length(c);
  if (which == SSL3_CHANGE_CIPHER_CLIENT_WRITE ||
      which == SSL3_CHANGE_CIPHER_SERVER_READ) {
    ms = &(p[0]);
    n = i + i;
    key = &(p[n]);
    n += j + j;
    iv = &(p[n]);
    n += k + k;
  } else {
    n = i;
    ms = &(p[n]);
    n += i + j;
    key = &(p[n]);
    n += j + k;
    iv = &(p[n]);
    n += k;
  }

  if (n > s->s3->tmp.key_block_length) {
    OPENSSL_PUT_ERROR(SSL, ssl3_change_cipher_state, ERR_R_INTERNAL_ERROR);
    goto err2;
  }

  memcpy(mac_secret, ms, i);

  if (!EVP_CipherInit_ex(dd, c, NULL, key, iv, (which & SSL3_CC_WRITE))) {
    goto err2;
  }

  OPENSSL_cleanse(&exp_key[0], sizeof(exp_key));
  OPENSSL_cleanse(&exp_iv[0], sizeof(exp_iv));
  return 1;

err:
  OPENSSL_PUT_ERROR(SSL, ssl3_change_cipher_state, ERR_R_MALLOC_FAILURE);
err2:
  return 0;
}

int ssl3_setup_key_block(SSL *s) {
  uint8_t *p;
  const EVP_CIPHER *c;
  const EVP_MD *hash;
  size_t num;
  int ret = 0;

  if (s->s3->tmp.key_block_length != 0) {
    return 1;
  }

  if (!ssl_cipher_get_evp(s->session, &c, &hash, NULL, NULL)) {
    OPENSSL_PUT_ERROR(SSL, ssl3_setup_key_block,
                      SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
    return 0;
  }

  s->s3->tmp.new_sym_enc = c;
  s->s3->tmp.new_hash = hash;

  num = EVP_MD_size(hash);

  num = EVP_CIPHER_key_length(c) + num + EVP_CIPHER_iv_length(c);
  num *= 2;

  ssl3_cleanup_key_block(s);

  p = OPENSSL_malloc(num);
  if (p == NULL) {
    goto err;
  }

  s->s3->tmp.key_block_length = num;
  s->s3->tmp.key_block = p;

  ret = ssl3_generate_key_block(s, p, num);

  /* enable vulnerability countermeasure for CBC ciphers with known-IV problem
   * (http://www.openssl.org/~bodo/tls-cbc.txt) */
  if ((s->mode & SSL_MODE_CBC_RECORD_SPLITTING) != 0) {
    s->s3->need_record_splitting = 1;

    if (s->session->cipher != NULL &&
        s->session->cipher->algorithm_enc == SSL_RC4) {
      s->s3->need_record_splitting = 0;
    }
  }

  return ret;

err:
  OPENSSL_PUT_ERROR(SSL, ssl3_setup_key_block, ERR_R_MALLOC_FAILURE);
  return 0;
}

void ssl3_cleanup_key_block(SSL *s) {
  if (s->s3->tmp.key_block != NULL) {
    OPENSSL_cleanse(s->s3->tmp.key_block, s->s3->tmp.key_block_length);
    OPENSSL_free(s->s3->tmp.key_block);
    s->s3->tmp.key_block = NULL;
  }
  s->s3->tmp.key_block_length = 0;
}

/* ssl3_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|,
 * respectively.
 *
 * Returns:
 *   0: (in non-constant time) if the record is publically invalid (i.e. too
 *       short etc).
 *   1: if the record's padding is valid / the encryption was successful.
 *   -1: if the record's padding is invalid or, if sending, an internal error
 *       occured. */
int ssl3_enc(SSL *s, int send) {
  SSL3_RECORD *rec;
  EVP_CIPHER_CTX *ds;
  unsigned long l;
  int bs, i, mac_size = 0;
  const EVP_CIPHER *enc = NULL;

  if (send) {
    ds = s->enc_write_ctx;
    rec = &(s->s3->wrec);
    if (s->enc_write_ctx != NULL) {
      enc = EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
    }
  } else {
    ds = s->enc_read_ctx;
    rec = &(s->s3->rrec);
    if (s->enc_read_ctx != NULL) {
      enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
    }
  }

  if (s->session == NULL || ds == NULL || enc == NULL) {
    memmove(rec->data, rec->input, rec->length);
    rec->input = rec->data;
  } else {
    l = rec->length;
    bs = EVP_CIPHER_block_size(ds->cipher);

    if (bs != 1 && send) {
      i = bs - ((int)l % bs);

      /* we need to add 'i-1' padding bytes */
      l += i;
      /* the last of these zero bytes will be overwritten with the padding
       * length. */
      memset(&rec->input[rec->length], 0, i);
      rec->length += i;
      rec->input[l - 1] = (i - 1);
    }

    if (!send) {
      if (l == 0 || l % bs != 0) {
        return 0;
      }
      /* otherwise, rec->length >= bs */
    }

    if (!EVP_Cipher(ds, rec->data, rec->input, l)) {
      return -1;
    }

    if (EVP_MD_CTX_md(s->read_hash) != NULL) {
      mac_size = EVP_MD_CTX_size(s->read_hash);
    }
    if (bs != 1 && !send) {
      return ssl3_cbc_remove_padding(s, rec, bs, mac_size);
    }
  }

  return 1;
}

int ssl3_init_finished_mac(SSL *s) {
  if (s->s3->handshake_buffer) {
    BIO_free(s->s3->handshake_buffer);
  }
  if (s->s3->handshake_dgst) {
    ssl3_free_digest_list(s);
  }
  s->s3->handshake_buffer = BIO_new(BIO_s_mem());
  if (s->s3->handshake_buffer == NULL) {
    return 0;
  }
  BIO_set_close(s->s3->handshake_buffer, BIO_CLOSE);

  return 1;
}

void ssl3_free_digest_list(SSL *s) {
  int i;
  if (!s->s3->handshake_dgst) {
    return;
  }
  for (i = 0; i < SSL_MAX_DIGEST; i++) {
    if (s->s3->handshake_dgst[i]) {
      EVP_MD_CTX_destroy(s->s3->handshake_dgst[i]);
    }
  }
  OPENSSL_free(s->s3->handshake_dgst);
  s->s3->handshake_dgst = NULL;
}

void ssl3_finish_mac(SSL *s, const uint8_t *buf, int len) {
  int i;

  if (s->s3->handshake_buffer) {
    BIO_write(s->s3->handshake_buffer, (void *)buf, len);
    return;
  }

  for (i = 0; i < SSL_MAX_DIGEST; i++) {
    if (s->s3->handshake_dgst[i] != NULL) {
      EVP_DigestUpdate(s->s3->handshake_dgst[i], buf, len);
    }
  }
}

int ssl3_digest_cached_records(
    SSL *s, enum should_free_handshake_buffer_t should_free_handshake_buffer) {
  int i;
  long mask;
  const EVP_MD *md;
  const uint8_t *hdata;
  size_t hdatalen;

  /* Allocate handshake_dgst array */
  ssl3_free_digest_list(s);
  s->s3->handshake_dgst = OPENSSL_malloc(SSL_MAX_DIGEST * sizeof(EVP_MD_CTX *));
  if (s->s3->handshake_dgst == NULL) {
    OPENSSL_PUT_ERROR(SSL, ssl3_digest_cached_records, ERR_R_MALLOC_FAILURE);
    return 0;
  }

  memset(s->s3->handshake_dgst, 0, SSL_MAX_DIGEST * sizeof(EVP_MD_CTX *));
  if (!BIO_mem_contents(s->s3->handshake_buffer, &hdata, &hdatalen)) {
    OPENSSL_PUT_ERROR(SSL, ssl3_digest_cached_records,
                      SSL_R_BAD_HANDSHAKE_LENGTH);
    return 0;
  }

  /* Loop through bits of algorithm2 field and create MD_CTX-es */
  for (i = 0; ssl_get_handshake_digest(i, &mask, &md); i++) {
    if ((mask & ssl_get_algorithm2(s)) && md) {
      s->s3->handshake_dgst[i] = EVP_MD_CTX_create();
      if (s->s3->handshake_dgst[i] == NULL) {
        OPENSSL_PUT_ERROR(SSL, ssl3_digest_cached_records, ERR_LIB_EVP);
        return 0;
      }
      if (!EVP_DigestInit_ex(s->s3->handshake_dgst[i], md, NULL)) {
        EVP_MD_CTX_destroy(s->s3->handshake_dgst[i]);
        s->s3->handshake_dgst[i] = NULL;
        OPENSSL_PUT_ERROR(SSL, ssl3_digest_cached_records, ERR_LIB_EVP);
        return 0;
      }
      EVP_DigestUpdate(s->s3->handshake_dgst[i], hdata, hdatalen);
    } else {
      s->s3->handshake_dgst[i] = NULL;
    }
  }

  if (should_free_handshake_buffer == free_handshake_buffer) {
    /* Free handshake_buffer BIO */
    BIO_free(s->s3->handshake_buffer);
    s->s3->handshake_buffer = NULL;
  }

  return 1;
}

int ssl3_cert_verify_mac(SSL *s, int md_nid, uint8_t *p) {
  return ssl3_handshake_mac(s, md_nid, NULL, 0, p);
}

int ssl3_final_finish_mac(SSL *s, const char *sender, int len, uint8_t *p) {
  int ret, sha1len;
  ret = ssl3_handshake_mac(s, NID_md5, sender, len, p);
  if (ret == 0) {
    return 0;
  }

  p += ret;

  sha1len = ssl3_handshake_mac(s, NID_sha1, sender, len, p);
  if (sha1len == 0) {
    return 0;
  }

  ret += sha1len;
  return ret;
}

static int ssl3_handshake_mac(SSL *s, int md_nid, const char *sender, int len,
                              uint8_t *p) {
  unsigned int ret;
  int npad, n;
  unsigned int i;
  uint8_t md_buf[EVP_MAX_MD_SIZE];
  EVP_MD_CTX ctx, *d = NULL;

  if (s->s3->handshake_buffer &&
      !ssl3_digest_cached_records(s, free_handshake_buffer)) {
    return 0;
  }

  /* Search for digest of specified type in the handshake_dgst array. */
  for (i = 0; i < SSL_MAX_DIGEST; i++) {
    if (s->s3->handshake_dgst[i] &&
        EVP_MD_CTX_type(s->s3->handshake_dgst[i]) == md_nid) {
      d = s->s3->handshake_dgst[i];
      break;
    }
  }

  if (!d) {
    OPENSSL_PUT_ERROR(SSL, ssl3_handshake_mac, SSL_R_NO_REQUIRED_DIGEST);
    return 0;
  }

  EVP_MD_CTX_init(&ctx);
  if (!EVP_MD_CTX_copy_ex(&ctx, d)) {
    EVP_MD_CTX_cleanup(&ctx);
    OPENSSL_PUT_ERROR(SSL, ssl3_generate_key_block, ERR_LIB_EVP);
    return 0;
  }

  n = EVP_MD_CTX_size(&ctx);
  if (n < 0) {
    return 0;
  }

  npad = (48 / n) * n;
  if (sender != NULL) {
    EVP_DigestUpdate(&ctx, sender, len);
  }
  EVP_DigestUpdate(&ctx, s->session->master_key, s->session->master_key_length);
  EVP_DigestUpdate(&ctx, ssl3_pad_1, npad);
  EVP_DigestFinal_ex(&ctx, md_buf, &i);

  if (!EVP_DigestInit_ex(&ctx, EVP_MD_CTX_md(&ctx), NULL)) {
    EVP_MD_CTX_cleanup(&ctx);
    OPENSSL_PUT_ERROR(SSL, ssl3_generate_key_block, ERR_LIB_EVP);
    return 0;
  }
  EVP_DigestUpdate(&ctx, s->session->master_key, s->session->master_key_length);
  EVP_DigestUpdate(&ctx, ssl3_pad_2, npad);
  EVP_DigestUpdate(&ctx, md_buf, i);
  EVP_DigestFinal_ex(&ctx, p, &ret);

  EVP_MD_CTX_cleanup(&ctx);

  return ret;
}

int n_ssl3_mac(SSL *ssl, uint8_t *md, int send) {
  SSL3_RECORD *rec;
  uint8_t *mac_sec, *seq;
  EVP_MD_CTX md_ctx;
  const EVP_MD_CTX *hash;
  uint8_t *p, rec_char;
  size_t md_size, orig_len;
  int npad;
  int t;

  if (send) {
    rec = &ssl->s3->wrec;
    mac_sec = &ssl->s3->write_mac_secret[0];
    seq = &ssl->s3->write_sequence[0];
    hash = ssl->write_hash;
  } else {
    rec = &ssl->s3->rrec;
    mac_sec = &ssl->s3->read_mac_secret[0];
    seq = &ssl->s3->read_sequence[0];
    hash = ssl->read_hash;
  }

  t = EVP_MD_CTX_size(hash);
  if (t < 0 || t > 20) {
    return -1;
  }
  md_size = t;
  npad = (48 / md_size) * md_size;

  /* kludge: ssl3_cbc_remove_padding passes padding length in rec->type */
  orig_len = rec->length + md_size + ((unsigned int)rec->type >> 8);
  rec->type &= 0xff;

  if (!send && EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
      ssl3_cbc_record_digest_supported(hash)) {
    /* This is a CBC-encrypted record. We must avoid leaking any timing-side
     * channel information about how many blocks of data we are hashing because
     * that gives an attacker a timing-oracle. */

    /* npad is, at most, 48 bytes and that's with MD5:
     *   16 + 48 + 8 (sequence bytes) + 1 + 2 = 75.
     *
     * With SHA-1 (the largest hash speced for SSLv3) the hash size goes up 4,
     * but npad goes down by 8, resulting in a smaller total size. */
    uint8_t header[75];
    unsigned j = 0;
    memcpy(header + j, mac_sec, md_size);
    j += md_size;
    memcpy(header + j, ssl3_pad_1, npad);
    j += npad;
    memcpy(header + j, seq, 8);
    j += 8;
    header[j++] = rec->type;
    header[j++] = rec->length >> 8;
    header[j++] = rec->length & 0xff;

    if (!ssl3_cbc_digest_record(hash, md, &md_size, header, rec->input,
                                rec->length + md_size, orig_len, mac_sec,
                                md_size, 1 /* is SSLv3 */)) {
      return -1;
    }
  } else {
    unsigned int md_size_u;
    /* Chop the digest off the end :-) */
    EVP_MD_CTX_init(&md_ctx);

    if (!EVP_MD_CTX_copy_ex(&md_ctx, hash)) {
      EVP_MD_CTX_cleanup(&md_ctx);
      return -1;
    }
    EVP_DigestUpdate(&md_ctx, mac_sec, md_size);
    EVP_DigestUpdate(&md_ctx, ssl3_pad_1, npad);
    EVP_DigestUpdate(&md_ctx, seq, 8);
    rec_char = rec->type;
    EVP_DigestUpdate(&md_ctx, &rec_char, 1);
    p = md;
    s2n(rec->length, p);
    EVP_DigestUpdate(&md_ctx, md, 2);
    EVP_DigestUpdate(&md_ctx, rec->input, rec->length);
    EVP_DigestFinal_ex(&md_ctx, md, NULL);

    if (!EVP_MD_CTX_copy_ex(&md_ctx, hash)) {
      EVP_MD_CTX_cleanup(&md_ctx);
      return -1;
    }
    EVP_DigestUpdate(&md_ctx, mac_sec, md_size);
    EVP_DigestUpdate(&md_ctx, ssl3_pad_2, npad);
    EVP_DigestUpdate(&md_ctx, md, md_size);
    EVP_DigestFinal_ex(&md_ctx, md, &md_size_u);
    md_size = md_size_u;

    EVP_MD_CTX_cleanup(&md_ctx);
  }

  ssl3_record_sequence_update(seq);
  return md_size;
}

void ssl3_record_sequence_update(uint8_t *seq) {
  int i;

  for (i = 7; i >= 0; i--) {
    ++seq[i];
    if (seq[i] != 0) {
      break;
    }
  }
}

int ssl3_generate_master_secret(SSL *s, uint8_t *out, uint8_t *p, int len) {
  uint8_t buf[EVP_MAX_MD_SIZE];
  EVP_MD_CTX ctx;
  int i, ret = 0;
  unsigned int n;

  EVP_MD_CTX_init(&ctx);
  for (i = 0; i < 3; i++) {
    if (!EVP_DigestInit_ex(&ctx, EVP_sha1(), NULL)) {
      ret = 0;
      break;
    }

    if (i == 0) {
      EVP_DigestUpdate(&ctx, (const uint8_t*) "A", 1);
    } else if (i == 1) {
      EVP_DigestUpdate(&ctx, (const uint8_t*) "BB", 2);
    } else {
      EVP_DigestUpdate(&ctx, (const uint8_t*) "CCC", 3);
    }
    EVP_DigestUpdate(&ctx, p, len);
    EVP_DigestUpdate(&ctx, &s->s3->client_random[0], SSL3_RANDOM_SIZE);
    EVP_DigestUpdate(&ctx, &s->s3->server_random[0], SSL3_RANDOM_SIZE);
    EVP_DigestFinal_ex(&ctx, buf, &n);

    if (!EVP_DigestInit_ex(&ctx, EVP_md5(), NULL)) {
      ret = 0;
      break;
    }

    EVP_DigestUpdate(&ctx, p, len);
    EVP_DigestUpdate(&ctx, buf, n);
    EVP_DigestFinal_ex(&ctx, out, &n);
    out += n;
    ret += n;
  }
  EVP_MD_CTX_cleanup(&ctx);

  return ret;
}

int ssl3_alert_code(int code) {
  switch (code) {
    case SSL_AD_CLOSE_NOTIFY:
      return SSL3_AD_CLOSE_NOTIFY;

    case SSL_AD_UNEXPECTED_MESSAGE:
      return SSL3_AD_UNEXPECTED_MESSAGE;

    case SSL_AD_BAD_RECORD_MAC:
      return SSL3_AD_BAD_RECORD_MAC;

    case SSL_AD_DECRYPTION_FAILED:
      return SSL3_AD_BAD_RECORD_MAC;

    case SSL_AD_RECORD_OVERFLOW:
      return SSL3_AD_BAD_RECORD_MAC;

    case SSL_AD_DECOMPRESSION_FAILURE:
      return SSL3_AD_DECOMPRESSION_FAILURE;

    case SSL_AD_HANDSHAKE_FAILURE:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_NO_CERTIFICATE:
      return SSL3_AD_NO_CERTIFICATE;

    case SSL_AD_BAD_CERTIFICATE:
      return SSL3_AD_BAD_CERTIFICATE;

    case SSL_AD_UNSUPPORTED_CERTIFICATE:
      return SSL3_AD_UNSUPPORTED_CERTIFICATE;

    case SSL_AD_CERTIFICATE_REVOKED:
      return SSL3_AD_CERTIFICATE_REVOKED;

    case SSL_AD_CERTIFICATE_EXPIRED:
      return SSL3_AD_CERTIFICATE_EXPIRED;

    case SSL_AD_CERTIFICATE_UNKNOWN:
      return SSL3_AD_CERTIFICATE_UNKNOWN;

    case SSL_AD_ILLEGAL_PARAMETER:
      return SSL3_AD_ILLEGAL_PARAMETER;

    case SSL_AD_UNKNOWN_CA:
      return SSL3_AD_BAD_CERTIFICATE;

    case SSL_AD_ACCESS_DENIED:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_DECODE_ERROR:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_DECRYPT_ERROR:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_EXPORT_RESTRICTION:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_PROTOCOL_VERSION:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_INSUFFICIENT_SECURITY:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_INTERNAL_ERROR:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_USER_CANCELLED:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_NO_RENEGOTIATION:
      return -1; /* Don't send it. */

    case SSL_AD_UNSUPPORTED_EXTENSION:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_CERTIFICATE_UNOBTAINABLE:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_UNRECOGNIZED_NAME:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_BAD_CERTIFICATE_HASH_VALUE:
      return SSL3_AD_HANDSHAKE_FAILURE;

    case SSL_AD_UNKNOWN_PSK_IDENTITY:
      return TLS1_AD_UNKNOWN_PSK_IDENTITY;

    case SSL_AD_INAPPROPRIATE_FALLBACK:
      return SSL3_AD_INAPPROPRIATE_FALLBACK;

    default:
      return -1;
  }
}