text: /*
   * Copyright (c) 1997 - 2007 Kungliga Tekniska Högskolan
   * (Royal Institute of Technology, Stockholm, Sweden).
   * 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. Neither the name of the Institute nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE 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.
   */
  
  #include "der_locl.h"
  
  /*
   * All decoding functions take a pointer `p' to first position in
   * which to read, from the left, `len' which means the maximum number
   * of characters we are able to read, `ret' were the value will be
   * returned and `size' where the number of used bytes is stored.
   * Either 0 or an error code is returned.
   */
  
  int ASN1CALL
  der_get_unsigned (const unsigned char *p, size_t len,
  		  unsigned *ret, size_t *size)
  {
      unsigned val = 0;
      size_t oldlen = len;
  
      if (len == sizeof(val) + 1 && p[0] == 0)
  	;
      else if (len > sizeof(val))
  	return ASN1_OVERRUN;
  
      while (len--)
  	val = val * 256 + *p++;
      *ret = val;
      if(size) *size = oldlen;
      return 0;
  }
  
  int ASN1CALL
  der_get_unsigned64 (const unsigned char *p, size_t len,
                     uint64_t *ret, size_t *size)
  {
      uint64_t val = 0;
      size_t oldlen = len;
  
      if (len == sizeof(val) + 1 && p[0] == 0)
         ;
      else if (len > sizeof(val))
  	return ASN1_OVERRUN;
  
      while (len--)
  	val = val * 256 + *p++;
      *ret = val;
      if(size) *size = oldlen;
      return 0;
  }
  
  int ASN1CALL
  der_get_integer (const unsigned char *p, size_t len,
  		 int *ret, size_t *size)
  {
      int val = 0;
      size_t oldlen = len;
  
      if (len > sizeof(val))
  	return ASN1_OVERRUN;
  
      if (len > 0) {
  	val = (signed char)*p++;
  	while (--len)
  	    val = val * 256 + *p++;
      }
      *ret = val;
      if(size) *size = oldlen;
      return 0;
  }
  
  int ASN1CALL
  der_get_integer64 (const unsigned char *p, size_t len,
  		   int64_t *ret, size_t *size)
  {
      int64_t val = 0;
      size_t oldlen = len;
  
      if (len > sizeof(val))
          return ASN1_OVERRUN;
  
      if (len > 0) {
         val = (signed char)*p++;
         while (--len)
             val = val * 256 + *p++;
      }
      *ret = val;
      if(size) *size = oldlen;
      return 0;
  }
  
  
  int ASN1CALL
  der_get_length (const unsigned char *p, size_t len,
  		size_t *val, size_t *size)
  {
      size_t v;
  
      if (len <= 0)
  	return ASN1_OVERRUN;
      --len;
      v = *p++;
      if (v < 128) {
  	*val = v;
  	if(size) *size = 1;
      } else {
  	int e;
  	size_t l;
  	unsigned tmp;
  
  	if(v == 0x80){
  	    *val = ASN1_INDEFINITE;
  	    if(size) *size = 1;
  	    return 0;
  	}
  	v &= 0x7F;
  	if (len < v)
  	    return ASN1_OVERRUN;
  	e = der_get_unsigned (p, v, &tmp, &l);
  	if(e) return e;
  	*val = tmp;
  	if(size) *size = l + 1;
      }
      return 0;
  }
  
  int ASN1CALL
  der_get_boolean(const unsigned char *p, size_t len, int *data, size_t *size)
  {
      if(len < 1)
  	return ASN1_OVERRUN;
      if(*p != 0)
  	*data = 1;
      else
  	*data = 0;
      *size = 1;
      return 0;
  }
  
  int ASN1CALL
  der_get_general_string (const unsigned char *p, size_t len,
  			heim_general_string *str, size_t *size)
  {
      const unsigned char *p1;
      char *s;
  
      p1 = memchr(p, 0, len);
      if (p1 != NULL) {
  	/*
  	 * Allow trailing NULs. We allow this since MIT Kerberos sends
  	 * an strings in the NEED_PREAUTH case that includes a
  	 * trailing NUL.
  	 */
  	while ((size_t)(p1 - p) < len && *p1 == '\0')
  	    p1++;
  	if ((size_t)(p1 - p) != len) {
  	    *str = NULL;
  	    return ASN1_BAD_CHARACTER;
  	}
      }
      if (len == SIZE_MAX) {
  	*str = NULL;
  	return ASN1_BAD_LENGTH;
      }
  
      *str = s = malloc (len + 1);
      if (s == NULL)
  	return ENOMEM;
      memcpy (s, p, len);
      s[len] = '\0';
  
      if(size) *size = len;
      return 0;
  }
  
  int ASN1CALL
  der_get_utf8string (const unsigned char *p, size_t len,
  		    heim_utf8_string *str, size_t *size)
  {
      return der_get_general_string(p, len, str, size);
  }
  
  #define gen_data_zero(_data) \
  	do { (_data)->length = 0; (_data)->data = NULL; } while(0)
  
  int ASN1CALL
  der_get_printable_string(const unsigned char *p, size_t len,
  			 heim_printable_string *str, size_t *size)
  {
      if (len == SIZE_MAX) {
  	gen_data_zero(str);
  	return ASN1_BAD_LENGTH;
      }
      str->length = len;
      str->data = malloc(len + 1);
      if (str->data == NULL) {
  	gen_data_zero(str);
  	return ENOMEM;
      }
      memcpy(str->data, p, len);
      ((char *)str->data)[len] = '\0';
      if(size) *size = len;
      return 0;
  }
  
  int ASN1CALL
  der_get_ia5_string(const unsigned char *p, size_t len,
  		   heim_ia5_string *str, size_t *size)
  {
      return der_get_printable_string(p, len, str, size);
  }
  
  int ASN1CALL
  der_get_bmp_string (const unsigned char *p, size_t len,
  		    heim_bmp_string *data, size_t *size)
  {
      size_t i;
  
      if (len & 1) {
  	gen_data_zero(data);
  	return ASN1_BAD_FORMAT;
      }
      data->length = len / 2;
      if (data->length > UINT_MAX/sizeof(data->data[0])) {
  	gen_data_zero(data);
  	return ERANGE;
      }
      data->data = malloc(data->length * sizeof(data->data[0]));
      if (data->data == NULL && data->length != 0) {
  	gen_data_zero(data);
  	return ENOMEM;
      }
  
      for (i = 0; i < data->length; i++) {
  	data->data[i] = (p[0] << 8) | p[1];
  	p += 2;
  	/* check for NUL in the middle of the string */
  	if (data->data[i] == 0 && i != (data->length - 1)) {
  	    free(data->data);
  	    gen_data_zero(data);
  	    return ASN1_BAD_CHARACTER;
  	}
      }
      if (size) *size = len;
  
      return 0;
  }
  
  int ASN1CALL
  der_get_universal_string (const unsigned char *p, size_t len,
  			  heim_universal_string *data, size_t *size)
  {
      size_t i;
  
      if (len & 3) {
  	gen_data_zero(data);
  	return ASN1_BAD_FORMAT;
      }
      data->length = len / 4;
      if (data->length > UINT_MAX/sizeof(data->data[0])) {
  	gen_data_zero(data);
  	return ERANGE;
      }
      data->data = malloc(data->length * sizeof(data->data[0]));
      if (data->data == NULL && data->length != 0) {
  	gen_data_zero(data);
  	return ENOMEM;
      }
  
      for (i = 0; i < data->length; i++) {
  	data->data[i] = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
  	p += 4;
  	/* check for NUL in the middle of the string */
  	if (data->data[i] == 0 && i != (data->length - 1)) {
  	    free(data->data);
  	    gen_data_zero(data);
  	    return ASN1_BAD_CHARACTER;
  	}
      }
      if (size) *size = len;
      return 0;
  }
  
  int ASN1CALL
  der_get_visible_string (const unsigned char *p, size_t len,
  			heim_visible_string *str, size_t *size)
  {
      return der_get_general_string(p, len, str, size);
  }
  
  int ASN1CALL
  der_get_octet_string (const unsigned char *p, size_t len,
  		      heim_octet_string *data, size_t *size)
  {
      data->length = len;
      data->data = malloc(len);
      if (data->data == NULL && data->length != 0)
  	return ENOMEM;
      memcpy (data->data, p, len);
      if(size) *size = len;
      return 0;
  }
  
  int ASN1CALL
  der_get_octet_string_ber (const unsigned char *p, size_t len,
  			  heim_octet_string *data, size_t *size)
  {
      int e;
      Der_type type;
      Der_class cls;
      unsigned int tag, depth = 0;
      size_t l, datalen, oldlen = len;
  
      data->length = 0;
      data->data = NULL;
  
      while (len) {
  	e = der_get_tag (p, len, &cls, &type, &tag, &l);
  	if (e) goto out;
  	if (cls != ASN1_C_UNIV) {
  	    e = ASN1_BAD_ID;
  	    goto out;
  	}
  	if (type == PRIM && tag == UT_EndOfContent) {
  	    if (depth == 0)
  		break;
  	    depth--;
  	}
  	if (tag != UT_OctetString) {
  	    e = ASN1_BAD_ID;
  	    goto out;
  	}
  
  	p += l;
  	len -= l;
  	e = der_get_length (p, len, &datalen, &l);
  	if (e) goto out;
  	p += l;
  	len -= l;
  
  	if (datalen > len)
  	    return ASN1_OVERRUN;
  
  	if (type == PRIM) {
  	    void *ptr;
  
  	    ptr = realloc(data->data, data->length + datalen);
  	    if (ptr == NULL) {
  		e = ENOMEM;
  		goto out;
  	    }
  	    data->data = ptr;
  	    memcpy(((unsigned char *)data->data) + data->length, p, datalen);
  	    data->length += datalen;
  	} else
  	    depth++;
  
  	p += datalen;
  	len -= datalen;
      }
      if (depth != 0)
  	return ASN1_INDEF_OVERRUN;
      if(size) *size = oldlen - len;
      return 0;
   out:
      free(data->data);
      data->data = NULL;
      data->length = 0;
      return e;
  }
  
  
  int ASN1CALL
  der_get_heim_integer (const unsigned char *p, size_t len,
  		      heim_integer *data, size_t *size)
  {
      data->length = 0;
      data->negative = 0;
      data->data = NULL;
  
      if (len == 0) {
  	if (size)
  	    *size = 0;
  	return 0;
      }
      if (p[0] & 0x80) {
  	unsigned char *q;
  	int carry = 1;
  	data->negative = 1;
  
  	data->length = len;
  
  	if (p[0] == 0xff) {
  	    p++;
  	    data->length--;
  	}
  	data->data = malloc(data->length);
  	if (data->data == NULL) {
  	    data->length = 0;
  	    if (size)
  		*size = 0;
  	    return ENOMEM;
  	}
  	q = &((unsigned char*)data->data)[data->length - 1];
  	p += data->length - 1;
  	while (q >= (unsigned char*)data->data) {
  	    *q = *p ^ 0xff;
  	    if (carry)
  		carry = !++*q;
  	    p--;
  	    q--;
  	}
      } else {
  	data->negative = 0;
  	data->length = len;
  
  	if (p[0] == 0) {
  	    p++;
  	    data->length--;
  	}
  	data->data = malloc(data->length);
  	if (data->data == NULL && data->length != 0) {
  	    data->length = 0;
  	    if (size)
  		*size = 0;
  	    return ENOMEM;
  	}
  	memcpy(data->data, p, data->length);
      }
      if (size)
  	*size = len;
      return 0;
  }
  
  static int
  generalizedtime2time (const char *s, time_t *t)
  {
      struct tm tm;
  
      memset(&tm, 0, sizeof(tm));
      if (sscanf (s, "%04d%02d%02d%02d%02d%02dZ",
  		&tm.tm_year, &tm.tm_mon, &tm.tm_mday, &tm.tm_hour,
  		&tm.tm_min, &tm.tm_sec) != 6) {
  	if (sscanf (s, "%02d%02d%02d%02d%02d%02dZ",
  		    &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &tm.tm_hour,
  		    &tm.tm_min, &tm.tm_sec) != 6)
  	    return ASN1_BAD_TIMEFORMAT;
  	if (tm.tm_year < 50)
  	    tm.tm_year += 2000;
  	else
  	    tm.tm_year += 1900;
      }
      tm.tm_year -= 1900;
      tm.tm_mon -= 1;
      *t = _der_timegm (&tm);
      return 0;
  }
  
  static int ASN1CALL
  der_get_time (const unsigned char *p, size_t len,
  	      time_t *data, size_t *size)
  {
      char *times;
      int e;
  
      if (len == SIZE_MAX || len == 0)
  	return ASN1_BAD_LENGTH;
  
      times = malloc(len + 1);
      if (times == NULL)
  	return ENOMEM;
      memcpy(times, p, len);
      times[len] = '\0';
      e = generalizedtime2time(times, data);
      free (times);
      if(size) *size = len;
      return e;
  }
  
  int ASN1CALL
  der_get_generalized_time (const unsigned char *p, size_t len,
  			  time_t *data, size_t *size)
  {
      return der_get_time(p, len, data, size);
  }
  
  int ASN1CALL
  der_get_utctime (const unsigned char *p, size_t len,
  			  time_t *data, size_t *size)
  {
      return der_get_time(p, len, data, size);
  }
  
  int ASN1CALL
  der_get_oid (const unsigned char *p, size_t len,
  	     heim_oid *data, size_t *size)
  {
      size_t n;
      size_t oldlen = len;
  
      if (len < 1)
  	return ASN1_OVERRUN;
  
      if (len == SIZE_MAX)
  	return ASN1_BAD_LENGTH;
  
      if (len + 1 > UINT_MAX/sizeof(data->components[0]))
  	return ERANGE;
  
      data->components = malloc((len + 1) * sizeof(data->components[0]));
      if (data->components == NULL)
  	return ENOMEM;
      data->components[0] = (*p) / 40;
      data->components[1] = (*p) % 40;
      --len;
      ++p;
      for (n = 2; len > 0; ++n) {
  	unsigned u = 0, u1;
  
  	do {
  	    --len;
  	    u1 = u * 128 + (*p++ % 128);
  	    /* check that we don't overflow the element */
  	    if (u1 < u) {
  		der_free_oid(data);
  		return ASN1_OVERRUN;
  	    }
  	    u = u1;
  	} while (len > 0 && p[-1] & 0x80);
  	data->components[n] = u;
      }
      if (n > 2 && p[-1] & 0x80) {
  	der_free_oid (data);
  	return ASN1_OVERRUN;
      }
      data->length = n;
      if (size)
  	*size = oldlen;
      return 0;
  }
  
  int ASN1CALL
  der_get_tag (const unsigned char *p, size_t len,
  	     Der_class *cls, Der_type *type,
  	     unsigned int *tag, size_t *size)
  {
      size_t ret = 0;
      if (len < 1)
  	return ASN1_OVERRUN;
      *cls = (Der_class)(((*p) >> 6) & 0x03);
      *type = (Der_type)(((*p) >> 5) & 0x01);
      *tag = (*p) & 0x1f;
      p++; len--; ret++;
      if(*tag == 0x1f) {
  	unsigned int continuation;
  	unsigned int tag1;
  	*tag = 0;
  	do {
  	    if(len < 1)
  		return ASN1_OVERRUN;
  	    continuation = *p & 128;
  	    tag1 = *tag * 128 + (*p % 128);
  	    /* check that we don't overflow the tag */
  	    if (tag1 < *tag)
  		return ASN1_OVERFLOW;
  	    *tag = tag1;
  	    p++; len--; ret++;
  	} while(continuation);
      }
      if(size) *size = ret;
      return 0;
  }
  
  int ASN1CALL
  der_match_tag (const unsigned char *p, size_t len,
  	       Der_class cls, Der_type type,
  	       unsigned int tag, size_t *size)
  {
      Der_type thistype;
      int e;
  
      e = der_match_tag2(p, len, cls, &thistype, tag, size);
      if (e) return e;
      if (thistype != type) return ASN1_BAD_ID;
      return 0;
  }
  
  int ASN1CALL
  der_match_tag2 (const unsigned char *p, size_t len,
  		Der_class cls, Der_type *type,
  		unsigned int tag, size_t *size)
  {
      size_t l;
      Der_class thisclass;
      unsigned int thistag;
      int e;
  
      e = der_get_tag (p, len, &thisclass, type, &thistag, &l);
      if (e) return e;
      if (cls != thisclass)
  	return ASN1_BAD_ID;
      if(tag > thistag)
  	return ASN1_MISPLACED_FIELD;
      if(tag < thistag)
  	return ASN1_MISSING_FIELD;
      if(size) *size = l;
      return 0;
  }
  
  int ASN1CALL
  der_match_tag_and_length (const unsigned char *p, size_t len,
  			  Der_class cls, Der_type *type, unsigned int tag,
  			  size_t *length_ret, size_t *size)
  {
      size_t l, ret = 0;
      int e;
  
      e = der_match_tag2 (p, len, cls, type, tag, &l);
      if (e) return e;
      p += l;
      len -= l;
      ret += l;
      e = der_get_length (p, len, length_ret, &l);
      if (e) return e;
      if(size) *size = ret + l;
      return 0;
  }
  
  
  
  /*
   * Old versions of DCE was based on a very early beta of the MIT code,
   * which used MAVROS for ASN.1 encoding. MAVROS had the interesting
   * feature that it encoded data in the forward direction, which has
   * it's problems, since you have no idea how long the data will be
   * until after you're done. MAVROS solved this by reserving one byte
   * for length, and later, if the actual length was longer, it reverted
   * to indefinite, BER style, lengths. The version of MAVROS used by
   * the DCE people could apparently generate correct X.509 DER encodings, and
   * did this by making space for the length after encoding, but
   * unfortunately this feature wasn't used with Kerberos.
   */
  
  int
  _heim_fix_dce(size_t reallen, size_t *len)
  {
      if(reallen == ASN1_INDEFINITE)
  	return 1;
      if(*len < reallen)
  	return -1;
      *len = reallen;
      return 0;
  }
  
  int ASN1CALL
  der_get_bit_string (const unsigned char *p, size_t len,
  		    heim_bit_string *data, size_t *size)
  {
      if (len < 1)
  	return ASN1_OVERRUN;
      if (p[0] > 7)
  	return ASN1_BAD_FORMAT;
      if (len - 1 == 0 && p[0] != 0)
  	return ASN1_BAD_FORMAT;
      /* check if any of the three upper bits are set
       * any of them will cause a interger overrun */
      if ((len - 1) >> (sizeof(len) * 8 - 3))
  	return ASN1_OVERRUN;
      /*
       * If there is data to copy, do that now.
       */
      if (len - 1 > 0) {
  	data->length = (len - 1) * 8;
  	data->data = malloc(len - 1);
  	if (data->data == NULL)
  	    return ENOMEM;
  	memcpy (data->data, p + 1, len - 1);
  	data->length -= p[0];
      } else {
  	data->data = NULL;
  	data->length = 0;
      }
      if(size) *size = len;
      return 0;
  }
  