text: /*
   * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the OpenSSL license (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  #include <limits.h>
  #include <stdio.h>
  #include <string.h>
  
  #include <openssl/asn1.h>
  #include <openssl/bn.h>
  #include <openssl/err.h>
  
  #include "asn1_locl.h"
  
  ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
  {
      return ASN1_STRING_dup(x);
  }
  
  int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
  {
      int neg, ret;
      /* Compare signs */
      neg = x->type & V_ASN1_NEG;
      if (neg != (y->type & V_ASN1_NEG)) {
          if (neg)
              return -1;
          else
              return 1;
      }
  
      ret = ASN1_STRING_cmp(x, y);
  
      if (neg)
          return -ret;
      else
          return ret;
  }
  
  /*
   * This converts a big endian buffer and sign into its content encoding.
   * This is used for INTEGER and ENUMERATED types.
   * The internal representation is an ASN1_STRING whose data is a big endian
   * representation of the value, ignoring the sign. The sign is determined by
   * the type: if type & V_ASN1_NEG is true it is negative, otherwise positive.
   *
   * Positive integers are no problem: they are almost the same as the DER
   * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
   *
   * Negative integers are a bit trickier...
   * The DER representation of negative integers is in 2s complement form.
   * The internal form is converted by complementing each octet and finally
   * adding one to the result. This can be done less messily with a little trick.
   * If the internal form has trailing zeroes then they will become FF by the
   * complement and 0 by the add one (due to carry) so just copy as many trailing
   * zeros to the destination as there are in the source. The carry will add one
   * to the last none zero octet: so complement this octet and add one and finally
   * complement any left over until you get to the start of the string.
   *
   * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
   * with 0xff. However if the first byte is 0x80 and one of the following bytes
   * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
   * followed by optional zeros isn't padded.
   */
  
  static size_t i2c_ibuf(const uint8_t *b, size_t blen, int neg,
                         uint8_t **pp)
  {
      int pad = 0;
      size_t ret, i;
      uint8_t *p, pb = 0;
      const uint8_t *n;
  
      if (b == NULL || blen == 0)
          ret = 1;
      else {
          ret = blen;
          i = b[0];
          if (ret == 1 && i == 0)
              neg = 0;
          if (!neg && (i > 127)) {
              pad = 1;
              pb = 0;
          } else if (neg) {
              if (i > 128) {
                  pad = 1;
                  pb = 0xFF;
              } else if (i == 128) {
                  /*
                   * Special case: if any other bytes non zero we pad:
                   * otherwise we don't.
                   */
                  for (i = 1; i < blen; i++)
                      if (b[i]) {
                          pad = 1;
                          pb = 0xFF;
                          break;
                      }
              }
          }
          ret += pad;
      }
      if (pp == NULL)
          return ret;
      p = *pp;
  
      if (pad)
          *(p++) = pb;
      if (b == NULL || blen == 0)
          *p = 0;
      else if (!neg)
          memcpy(p, b, blen);
      else {
          /* Begin at the end of the encoding */
          n = b + blen - 1;
          p += blen - 1;
          i = blen;
          /* Copy zeros to destination as long as source is zero */
          while (!*n && i > 1) {
              *(p--) = 0;
              n--;
              i--;
          }
          /* Complement and increment next octet */
          *(p--) = ((*(n--)) ^ 0xff) + 1;
          i--;
          /* Complement any octets left */
          for (; i > 0; i--)
              *(p--) = *(n--) ^ 0xff;
      }
  
      *pp += ret;
      return ret;
  }
  
  /*
   * convert content octets into a big endian buffer. Returns the length
   * of buffer or 0 on error: for malformed INTEGER. If output bufer is
   * NULL just return length.
   */
  
  static size_t c2i_ibuf(uint8_t *b, int *pneg,
                         const uint8_t *p, size_t plen)
  {
      size_t i;
      int neg, pad;
      /* Zero content length is illegal */
      if (plen == 0) {
          ASN1err(ASN1_F_C2I_IBUF, ASN1_R_ILLEGAL_ZERO_CONTENT);
          return 0;
      }
      neg = p[0] & 0x80;
      if (pneg)
          *pneg = neg;
      /* Handle common case where length is 1 octet separately */
      if (plen == 1) {
          if (b) {
              if (neg)
                  b[0] = (p[0] ^ 0xFF) + 1;
              else
                  b[0] = p[0];
          }
          return 1;
      }
      if (p[0] == 0 || p[0] == 0xFF)
          pad = 1;
      else
          pad = 0;
      /* reject illegal padding: first two octets MSB can't match */
      if (pad && (neg == (p[1] & 0x80))) {
          ASN1err(ASN1_F_C2I_IBUF, ASN1_R_ILLEGAL_PADDING);
          return 0;
      }
      /* If positive just copy across */
      if (neg == 0) {
          if (b)
              memcpy(b, p + pad, plen - pad);
          return plen - pad;
      }
  
      if (neg && pad) {
          /* check is any following octets are non zero */
          for (i = 1; i < plen; i++) {
              if (p[i] != 0)
                  break;
          }
          /* if all bytes are zero handle as special case */
          if (i == plen) {
              if (b) {
                  b[0] = 1;
                  memset(b + 1, 0, plen - 1);
              }
              return plen;
          }
      }
  
      plen -= pad;
      /* Must be negative: calculate twos complement */
      if (b) {
          const uint8_t *from = p + plen - 1 + pad;
          uint8_t *to = b + plen - 1;
          i = plen;
          while (*from == 0 && i) {
              *to-- = 0;
              i--;
              from--;
          }
          *to-- = (*from-- ^ 0xff) + 1;
          OPENSSL_assert(i != 0);
          i--;
          for (; i > 0; i--)
              *to-- = *from-- ^ 0xff;
      }
      return plen;
  }
  
  int i2c_ASN1_INTEGER(ASN1_INTEGER *a, uint8_t **pp)
  {
      return i2c_ibuf(a->data, a->length, a->type & V_ASN1_NEG, pp);
  }
  
  /* Convert big endian buffer into uint64_t, return 0 on error */
  static int asn1_get_uint64(uint64_t *pr, const uint8_t *b, size_t blen)
  {
      size_t i;
      if (blen > sizeof(*pr)) {
          ASN1err(ASN1_F_ASN1_GET_UINT64, ASN1_R_TOO_LARGE);
          return 0;
      }
      *pr = 0;
      if (b == NULL)
          return 0;
      for (i = 0; i < blen; i++) {
          *pr <<= 8;
          *pr |= b[i];
      }
      return 1;
  }
  
  static size_t asn1_put_uint64(uint8_t *b, uint64_t r)
  {
      if (r >= 0x100) {
          uint8_t *p;
          uint64_t rtmp = r;
          size_t i = 0;
  
          /* Work out how many bytes we need */
          while (rtmp) {
              rtmp >>= 8;
              i++;
          }
  
          /* Copy from end to beginning */
          p = b + i - 1;
  
          do {
              *p-- = r & 0xFF;
              r >>= 8;
          } while (p >= b);
  
          return i;
      }
  
      b[0] = (uint8_t)r;
      return 1;
  
  }
  
  /*
   * Absolute value of INT64_MIN: we can't just use -INT64_MIN as it produces
   * overflow warnings.
   */
  
  #define ABS_INT64_MIN \
      ((uint64_t)INT64_MAX + (uint64_t)(-(INT64_MIN + INT64_MAX)))
  
  /* signed version of asn1_get_uint64 */
  static int asn1_get_int64(int64_t *pr, const uint8_t *b, size_t blen,
                            int neg)
  {
      uint64_t r;
      if (asn1_get_uint64(&r, b, blen) == 0)
          return 0;
      if (neg) {
          if (r > ABS_INT64_MIN) {
              ASN1err(ASN1_F_ASN1_GET_INT64, ASN1_R_TOO_SMALL);
              return 0;
          }
          *pr = -(int64_t)r;
      } else {
          if (r > INT64_MAX) {
              ASN1err(ASN1_F_ASN1_GET_INT64, ASN1_R_TOO_LARGE);
              return 0;
          }
          *pr = (int64_t)r;
      }
      return 1;
  }
  
  /* Convert ASN1 INTEGER content octets to ASN1_INTEGER structure */
  ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const uint8_t **pp,
                                 long len)
  {
      ASN1_INTEGER *ret = NULL;
      size_t r;
      int neg;
  
      r = c2i_ibuf(NULL, NULL, *pp, len);
  
      if (r == 0)
          return NULL;
  
      if ((a == NULL) || ((*a) == NULL)) {
          ret = ASN1_INTEGER_new();
          if (ret == NULL)
              return NULL;
          ret->type = V_ASN1_INTEGER;
      } else
          ret = *a;
  
      if (ASN1_STRING_set(ret, NULL, r) == 0)
          goto err;
  
      c2i_ibuf(ret->data, &neg, *pp, len);
  
      if (neg)
          ret->type |= V_ASN1_NEG;
  
      *pp += len;
      if (a != NULL)
          (*a) = ret;
      return ret;
   err:
      ASN1err(ASN1_F_C2I_ASN1_INTEGER, ERR_R_MALLOC_FAILURE);
      if ((a == NULL) || (*a != ret))
          ASN1_INTEGER_free(ret);
      return NULL;
  }
  
  static int asn1_string_get_int64(int64_t *pr, const ASN1_STRING *a, int itype)
  {
      if (a == NULL) {
          ASN1err(ASN1_F_ASN1_STRING_GET_INT64, ERR_R_PASSED_NULL_PARAMETER);
          return 0;
      }
      if ((a->type & ~V_ASN1_NEG) != itype) {
          ASN1err(ASN1_F_ASN1_STRING_GET_INT64, ASN1_R_WRONG_INTEGER_TYPE);
          return 0;
      }
      return asn1_get_int64(pr, a->data, a->length, a->type & V_ASN1_NEG);
  }
  
  static int asn1_string_set_int64(ASN1_STRING *a, int64_t r, int itype)
  {
      uint8_t tbuf[sizeof(r)];
      size_t l;
      a->type = itype;
      if (r < 0) {
          l = asn1_put_uint64(tbuf, -r);
          a->type |= V_ASN1_NEG;
      } else {
          l = asn1_put_uint64(tbuf, r);
          a->type &= ~V_ASN1_NEG;
      }
      if (l == 0)
          return 0;
      return ASN1_STRING_set(a, tbuf, l);
  }
  
  /*
   * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1
   * integers: some broken software can encode a positive INTEGER with its MSB
   * set as negative (it doesn't add a padding zero).
   */
  
  ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const uint8_t **pp,
                                  long length)
  {
      ASN1_INTEGER *ret = NULL;
      const uint8_t *p;
      uint8_t *s;
      long len;
      int inf, tag, xclass;
      int i;
  
      if ((a == NULL) || ((*a) == NULL)) {
          if ((ret = ASN1_INTEGER_new()) == NULL)
              return (NULL);
          ret->type = V_ASN1_INTEGER;
      } else
          ret = (*a);
  
      p = *pp;
      inf = ASN1_get_object(&p, &len, &tag, &xclass, length);
      if (inf & 0x80) {
          i = ASN1_R_BAD_OBJECT_HEADER;
          goto err;
      }
  
      if (tag != V_ASN1_INTEGER) {
          i = ASN1_R_EXPECTING_AN_INTEGER;
          goto err;
      }
  
      /*
       * We must malloc stuff, even for 0 bytes otherwise it signifies
       * a missing NULL parameter.
       */
      s = malloc((int)len + 1);
      if (s == NULL) {
          i = ERR_R_MALLOC_FAILURE;
          goto err;
      }
      ret->type = V_ASN1_INTEGER;
      if (len) {
          if ((*p == 0) && (len != 1)) {
              p++;
              len--;
          }
          memcpy(s, p, (int)len);
          p += len;
      }
  
      free(ret->data);
      ret->data = s;
      ret->length = (int)len;
      if (a != NULL)
          (*a) = ret;
      *pp = p;
      return (ret);
   err:
      ASN1err(ASN1_F_D2I_ASN1_UINTEGER, i);
      if ((a == NULL) || (*a != ret))
          ASN1_INTEGER_free(ret);
      return (NULL);
  }
  
  static ASN1_STRING *bn_to_asn1_string(const BIGNUM *bn, ASN1_STRING *ai,
                                        int atype)
  {
      ASN1_INTEGER *ret;
      int len;
  
      if (ai == NULL) {
          ret = ASN1_STRING_type_new(atype);
      } else {
          ret = ai;
          ret->type = atype;
      }
  
      if (ret == NULL) {
          ASN1err(ASN1_F_BN_TO_ASN1_STRING, ERR_R_NESTED_ASN1_ERROR);
          goto err;
      }
  
      if (BN_is_negative(bn) && !BN_is_zero(bn))
          ret->type |= V_ASN1_NEG_INTEGER;
  
      len = BN_num_bytes(bn);
  
      if (len == 0)
          len = 1;
  
      if (ASN1_STRING_set(ret, NULL, len) == 0) {
          ASN1err(ASN1_F_BN_TO_ASN1_STRING, ERR_R_MALLOC_FAILURE);
          goto err;
      }
  
      /* Correct zero case */
      if (BN_is_zero(bn))
          ret->data[0] = 0;
      else
          len = BN_bn2bin(bn, ret->data);
      ret->length = len;
      return ret;
   err:
      if (ret != ai)
          ASN1_INTEGER_free(ret);
      return (NULL);
  }
  
  static BIGNUM *asn1_string_to_bn(const ASN1_INTEGER *ai, BIGNUM *bn,
                                   int itype)
  {
      BIGNUM *ret;
  
      if ((ai->type & ~V_ASN1_NEG) != itype) {
          ASN1err(ASN1_F_ASN1_STRING_TO_BN, ASN1_R_WRONG_INTEGER_TYPE);
          return NULL;
      }
  
      ret = BN_bin2bn(ai->data, ai->length, bn);
      if (ret == 0) {
          ASN1err(ASN1_F_ASN1_STRING_TO_BN, ASN1_R_BN_LIB);
          return NULL;
      }
      if (ai->type & V_ASN1_NEG)
          BN_set_negative(ret, 1);
      return ret;
  }
  
  int ASN1_INTEGER_get_int64(int64_t *pr, const ASN1_INTEGER *a)
  {
      return asn1_string_get_int64(pr, a, V_ASN1_INTEGER);
  }
  
  int ASN1_INTEGER_set_int64(ASN1_INTEGER *a, int64_t r)
  {
      return asn1_string_set_int64(a, r, V_ASN1_INTEGER);
  }
  
  int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
  {
      return ASN1_INTEGER_set_int64(a, v);
  }
  
  long ASN1_INTEGER_get(const ASN1_INTEGER *a)
  {
      int i;
      int64_t r;
      if (a == NULL)
          return 0;
      i = ASN1_INTEGER_get_int64(&r, a);
      if (i == 0)
          return -1;
      if (r > INT64_MAX || r < INT64_MIN)
          return -1;
      return (long)r;
  }
  
  ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
  {
      return bn_to_asn1_string(bn, ai, V_ASN1_INTEGER);
  }
  
  BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
  {
      return asn1_string_to_bn(ai, bn, V_ASN1_INTEGER);
  }
  
  int ASN1_ENUMERATED_get_int64(int64_t *pr, const ASN1_ENUMERATED *a)
  {
      return asn1_string_get_int64(pr, a, V_ASN1_ENUMERATED);
  }
  
  int ASN1_ENUMERATED_set_int64(ASN1_ENUMERATED *a, int64_t r)
  {
      return asn1_string_set_int64(a, r, V_ASN1_ENUMERATED);
  }
  
  int ASN1_ENUMERATED_set(ASN1_ENUMERATED *a, long v)
  {
      return ASN1_ENUMERATED_set_int64(a, v);
  }
  
  long ASN1_ENUMERATED_get(ASN1_ENUMERATED *a)
  {
      int i;
      int64_t r;
      if (a == NULL)
          return 0;
      if ((a->type & ~V_ASN1_NEG) != V_ASN1_ENUMERATED)
          return -1;
      if (a->length > (int)sizeof(long))
          return 0xffffffffL;
      i = ASN1_ENUMERATED_get_int64(&r, a);
      if (i == 0)
          return -1;
      if (r > INT64_MAX || r < INT64_MIN)
          return -1;
      return (long)r;
  }
  
  ASN1_ENUMERATED *BN_to_ASN1_ENUMERATED(const BIGNUM *bn, ASN1_ENUMERATED *ai)
  {
      return bn_to_asn1_string(bn, ai, V_ASN1_ENUMERATED);
  }
  
  BIGNUM *ASN1_ENUMERATED_to_BN(const ASN1_ENUMERATED *ai, BIGNUM *bn)
  {
      return asn1_string_to_bn(ai, bn, V_ASN1_ENUMERATED);
  }
  