/* $OpenBSD: rsa_pk1.c,v 1.15 2017/01/29 17:49:23 beck 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.]

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <openssl/bn.h>

#include <openssl/err.h>

#include <openssl/rsa.h>

int

RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,

    const unsigned char *from, int flen)

{

  int j;

  unsigned char *p;

  if (flen > (tlen - RSA_PKCS1_PADDING_SIZE)) {

    RSAerror(RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);

    return 0;

  }

  p = (unsigned char *)to;

  *(p++) = 0;

  *(p++) = 1; /* Private Key BT (Block Type) */

  /* pad out with 0xff data */

  j = tlen - 3 - flen;

  memset(p, 0xff, j);

  p += j;

  *(p++) = '\0';

  memcpy(p, from, flen);

  return 1;

}

int

RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen,

    const unsigned char *from, int flen, int num)

{

  int i, j;

  const unsigned char *p;

  p = from;

  if (num != flen + 1 || *(p++) != 01) {

    RSAerror(RSA_R_BLOCK_TYPE_IS_NOT_01);

    return -1;

  }

  /* scan over padding data */

  j = flen - 1; /* one for type. */

  for (i = 0; i < j; i++) {

    if (*p != 0xff) {

      /* should decrypt to 0xff */

      if (*p == 0) {

        p++;

        break;

      } else {

        RSAerror(RSA_R_BAD_FIXED_HEADER_DECRYPT);

        return -1;

      }

    }

    p++;

  }

  if (i == j) {

    RSAerror(RSA_R_NULL_BEFORE_BLOCK_MISSING);

    return -1;

  }

  if (i < 8) {

    RSAerror(RSA_R_BAD_PAD_BYTE_COUNT);

    return -1;

  }

  i++; /* Skip over the '\0' */

  j -= i;

  if (j > tlen) {

    RSAerror(RSA_R_DATA_TOO_LARGE);

    return -1;

  }

  memcpy(to, p, j);

  return j;

}

int

RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,

    const unsigned char *from, int flen)

{

  int i, j;

  unsigned char *p;

  if (flen > tlen - 11) {

    RSAerror(RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);

    return 0;

  }

  p = (unsigned char *)to;

  *(p++) = 0;

  *(p++) = 2; /* Public Key BT (Block Type) */

  /* pad out with non-zero random data */

  j = tlen - 3 - flen;

  arc4random_buf(p, j);

  for (i = 0; i < j; i++) {

    while (*p == '\0')

      arc4random_buf(p, 1);

    p++;

  }

  *(p++) = '\0';

  memcpy(p, from, flen);

  return 1;

}

int

RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,

    const unsigned char *from, int flen, int num)

{

  int i, j;

  const unsigned char *p;

  p = from;

  if (num != flen + 1 || *(p++) != 02) {

    RSAerror(RSA_R_BLOCK_TYPE_IS_NOT_02);

    return -1;

  }

  /* scan over padding data */

  j = flen - 1; /* one for type. */

  for (i = 0; i < j; i++)

    if (*(p++) == 0)

      break;

  if (i == j) {

    RSAerror(RSA_R_NULL_BEFORE_BLOCK_MISSING);

    return -1;

  }

  if (i < 8) {

    RSAerror(RSA_R_BAD_PAD_BYTE_COUNT);

    return -1;

  }

  i++; /* Skip over the '\0' */

  j -= i;

  if (j > tlen) {

    RSAerror(RSA_R_DATA_TOO_LARGE);

    return -1;

  }

  memcpy(to, p, j);

  return j;

}