/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 *

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 *

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 *

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.] */

#include <openssl/asn1.h>

#include <limits.h>

#include <string.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include "../internal.h"

#include "internal.h"

int ASN1_BIT_STRING_set(ASN1_BIT_STRING *x, const unsigned char *d,

                        ossl_ssize_t len) {

  return ASN1_STRING_set(x, d, len);

}

int asn1_bit_string_length(const ASN1_BIT_STRING *str,

                           uint8_t *out_padding_bits) {

  int len = str->length;

  if (str->flags & ASN1_STRING_FLAG_BITS_LEFT) {

    // If the string is already empty, it cannot have padding bits.

    *out_padding_bits = len == 0 ? 0 : str->flags & 0x07;

    return len;

  }

  // TODO(https://crbug.com/boringssl/447): If we move this logic to

  // |ASN1_BIT_STRING_set_bit|, can we remove this representation?

  while (len > 0 && str->data[len - 1] == 0) {

    len--;

  }

  uint8_t padding_bits = 0;

  if (len > 0) {

    uint8_t last = str->data[len - 1];

    assert(last != 0);

    for (; padding_bits < 7; padding_bits++) {

      if (last & (1 << padding_bits)) {

        break;

      }

    }

  }

  *out_padding_bits = padding_bits;

  return len;

}

int ASN1_BIT_STRING_num_bytes(const ASN1_BIT_STRING *str, size_t *out) {

  uint8_t padding_bits;

  int len = asn1_bit_string_length(str, &padding_bits);

  if (padding_bits != 0) {

    return 0;

  }

  *out = len;

  return 1;

}

int i2c_ASN1_BIT_STRING(const ASN1_BIT_STRING *a, unsigned char **pp) {

  if (a == NULL) {

    return 0;

  }

  uint8_t bits;

  int len = asn1_bit_string_length(a, &bits);

  if (len > INT_MAX - 1) {

    OPENSSL_PUT_ERROR(ASN1, ERR_R_OVERFLOW);

    return 0;

  }

  int ret = 1 + len;

  if (pp == NULL) {

    return ret;

  }

  uint8_t *p = *pp;

  *(p++) = bits;

  OPENSSL_memcpy(p, a->data, len);

  if (len > 0) {

    p[len - 1] &= (0xff << bits);

  }

  p += len;

  *pp = p;

  return ret;

}

ASN1_BIT_STRING *c2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a,

                                     const unsigned char **pp, long len) {

  ASN1_BIT_STRING *ret = NULL;

  const unsigned char *p;

  unsigned char *s;

  int padding;

  if (len < 1) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_STRING_TOO_SHORT);

    goto err;

  }

  if (len > INT_MAX) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_STRING_TOO_LONG);

    goto err;

  }

  if ((a == NULL) || ((*a) == NULL)) {

    if ((ret = ASN1_BIT_STRING_new()) == NULL) {

      return NULL;

    }

  } else {

    ret = (*a);

  }

  p = *pp;

  padding = *(p++);

  len--;

  if (padding > 7) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_INVALID_BIT_STRING_BITS_LEFT);

    goto err;

  }

  // Unused bits in a BIT STRING must be zero.

  uint8_t padding_mask = (1 << padding) - 1;

  if (padding != 0 && (len < 1 || (p[len - 1] & padding_mask) != 0)) {

    OPENSSL_PUT_ERROR(ASN1, ASN1_R_INVALID_BIT_STRING_PADDING);

    goto err;

  }

  // We do this to preserve the settings.  If we modify the settings, via

  // the _set_bit function, we will recalculate on output

  ret->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);    // clear

  ret->flags |= (ASN1_STRING_FLAG_BITS_LEFT | padding);  // set

  if (len > 0) {

    s = OPENSSL_memdup(p, len);

    if (s == NULL) {

      goto err;

    }

    p += len;

  } else {

    s = NULL;

  }

  ret->length = (int)len;

  OPENSSL_free(ret->data);

  ret->data = s;

  ret->type = V_ASN1_BIT_STRING;

  if (a != NULL) {

    (*a) = ret;

  }

  *pp = p;

  return ret;

err:

  if ((ret != NULL) && ((a == NULL) || (*a != ret))) {

    ASN1_BIT_STRING_free(ret);

  }

  return NULL;

}

// These next 2 functions from Goetz Babin-Ebell <babinebell@trustcenter.de>

int ASN1_BIT_STRING_set_bit(ASN1_BIT_STRING *a, int n, int value) {

  int w, v, iv;

  unsigned char *c;

  w = n / 8;

  v = 1 << (7 - (n & 0x07));

  iv = ~v;

  if (!value) {

    v = 0;

  }

  if (a == NULL) {

    return 0;

  }

  a->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);  // clear, set on write

  if ((a->length < (w + 1)) || (a->data == NULL)) {

    if (!value) {

      return 1;  // Don't need to set

    }

    if (a->data == NULL) {

      c = (unsigned char *)OPENSSL_malloc(w + 1);

    } else {

      c = (unsigned char *)OPENSSL_realloc(a->data, w + 1);

    }

    if (c == NULL) {

      return 0;

    }

    if (w + 1 - a->length > 0) {

      OPENSSL_memset(c + a->length, 0, w + 1 - a->length);

    }

    a->data = c;

    a->length = w + 1;

  }

  a->data[w] = ((a->data[w]) & iv) | v;

  while ((a->length > 0) && (a->data[a->length - 1] == 0)) {

    a->length--;

  }

  return 1;

}

int ASN1_BIT_STRING_get_bit(const ASN1_BIT_STRING *a, int n) {

  int w, v;

  w = n / 8;

  v = 1 << (7 - (n & 0x07));

  if ((a == NULL) || (a->length < (w + 1)) || (a->data == NULL)) {

    return 0;

  }

  return ((a->data[w] & v) != 0);

}

// Checks if the given bit string contains only bits specified by

// the flags vector. Returns 0 if there is at least one bit set in 'a'

// which is not specified in 'flags', 1 otherwise.

// 'len' is the length of 'flags'.

int ASN1_BIT_STRING_check(const ASN1_BIT_STRING *a, const unsigned char *flags,

                          int flags_len) {

  int i, ok;

  // Check if there is one bit set at all.

  if (!a || !a->data) {

    return 1;

  }

  // Check each byte of the internal representation of the bit string.

  ok = 1;

  for (i = 0; i < a->length && ok; ++i) {

    unsigned char mask = i < flags_len ? ~flags[i] : 0xff;

    // We are done if there is an unneeded bit set.

    ok = (a->data[i] & mask) == 0;

  }

  return ok;

}