asn1.c

eCos操作系统源码

    if (intsize != sizeof (long)){
	_asn_size_err(errpre, intsize, sizeof(long));
	return NULL;
    }
    integer = *intp;
    mask = ((u_long) 0xFF) << (8 * (sizeof(long) - 1));
    /* mask is 0xFF000000 on a big-endian machine */
    if ((u_char)((integer & mask) >> (8 * (sizeof(long) - 1))) & 0x80){
	/* if MSB is set */
	add_null_byte = 1;
	intsize++;
    } else {
	/*
	 * Truncate "unnecessary" bytes off of the most significant end of this 2's complement integer.
	 * There should be no sequence of 9 consecutive 1's or 0's at the most significant end of the
	 * integer.
	 */
	mask = ((u_long) 0x1FF) << ((8 * (sizeof(long) - 1)) - 1);
	/* mask is 0xFF800000 on a big-endian machine */
	while((((integer & mask) == 0) || ((integer & mask) == mask)) && intsize > 1){
	    intsize--;
	    integer <<= 8;
	}
    }
    data = asn_build_header(data, datalength, type, intsize);
    if (_asn_build_header_check(errpre,data,*datalength,intsize))
	return NULL;

    *datalength -= intsize;
    if (add_null_byte == 1){
	*data++ = '\0';
	intsize--;
    }
    mask = ((u_long) 0xFF) << (8 * (sizeof(long) - 1));
    /* mask is 0xFF000000 on a big-endian machine */
    while(intsize--){
	*data++ = (u_char)((integer & mask) >> (8 * (sizeof(long) - 1)));
	integer <<= 8;
    }
    return data;
}


/*
 * asn_parse_string - pulls an octet string out of an ASN octet string type.
 *  On entry, datalength is input as the number of valid bytes following
 *   "data".  On exit, it is returned as the number of valid bytes
 *   following the beginning of the next object.
 *
 *  "string" is filled with the octet string.
 *
 *  Returns a pointer to the first byte past the end
 *   of this object (i.e. the start of the next object).
 *  Returns NULL on any error.
 *
 * u_char * asn_parse_string(
 *     u_char     *data         IN - pointer to start of object
 *     int        *datalength   IN/OUT - number of valid bytes left in buffer
 *     u_char     *type         OUT - asn type of object
 *     u_char     *string       IN/OUT - pointer to start of output buffer
 *     int        *strlength    IN/OUT - size of output buffer
 *
 *
 * ASN.1 octet string	::=      primstring | cmpdstring
 * primstring		::= 0x04 asnlength byte {byte}*
 * cmpdstring		::= 0x24 asnlength string {string}*
 */
u_char *
asn_parse_string(u_char *data,
		 size_t *datalength,
		 u_char *type,
		 u_char *string,
		 size_t *strlength)
{
    static const char *errpre = "parse string";
    u_char *bufp = data;
    u_long  asn_length;

    *type = *bufp++;
    bufp = asn_parse_length(bufp, &asn_length);
    if (_asn_parse_length_check(errpre, bufp, data, asn_length, *datalength))
	return NULL;

    if ((int)asn_length > *strlength){
	_asn_length_err(errpre, (size_t)asn_length, *strlength);
	return NULL;
    }

    DEBUGDUMPSETUP("dump_recv", data, bufp - data + asn_length);

    memmove(string, bufp, asn_length);
    if (*strlength > (int)asn_length)
      string[asn_length] = 0;
    *strlength = (int)asn_length;
    *datalength -= (int)asn_length + (bufp - data);

    DEBUGIF("dump_recv") {
      char *buf = (char *)malloc(1+asn_length);
      sprint_asciistring(buf, string, asn_length);
      DEBUGMSG(("dump_recv", "  ASN String:\t%s\n", buf));
      free (buf);
    }
        
    return bufp + asn_length;
}


/*
 * asn_build_string - Builds an ASN octet string object containing the input string.
 *  On entry, datalength is input as the number of valid bytes following
 *   "data".  On exit, it is returned as the number of valid bytes
 *   following the beginning of the next object.
 *
 *  Returns a pointer to the first byte past the end
 *   of this object (i.e. the start of the next object).
 *  Returns NULL on any error.

  u_char * asn_build_string(
      u_char     *data         IN - pointer to start of object
      int        *datalength   IN/OUT - number of valid bytes left in buffer
      u_char      type         IN - asn type of object
      u_char     *string       IN - pointer to start of input buffer
      int         strlength    IN - size of input buffer
 */
u_char *
asn_build_string(u_char *data,
		 size_t *datalength,
		 u_char	type,
		 const u_char *string,
		 size_t strlength)
{
/*
 * ASN.1 octet string ::= primstring | cmpdstring
 * primstring ::= 0x04 asnlength byte {byte}*
 * cmpdstring ::= 0x24 asnlength string {string}*
 * This code will never send a compound string.
 */
    data = asn_build_header(data, datalength, type, strlength);
    if (_asn_build_header_check("build string", data, *datalength, strlength))
	return NULL;

    if (strlength) {
      if (string == NULL) {
	memset(data, 0, strlength);
      } else {
	memmove(data, string, strlength);
      }
    }
    *datalength -= strlength;
    return data + strlength;
}



/*
 * asn_parse_header - interprets the ID and length of the current object.
 *  On entry, datalength is input as the number of valid bytes following
 *   "data".  On exit, it is returned as the number of valid bytes
 *   in this object following the id and length.
 *
 *  Returns a pointer to the first byte of the contents of this object.
 *  Returns NULL on any error.

  u_char * asn_parse_header(
      u_char     *data         IN - pointer to start of object
      int        *datalength   IN/OUT - number of valid bytes left in buffer
      u_char     *type         OUT - asn type of object
 */
u_char *
asn_parse_header(u_char	*data,
		 size_t *datalength,
		 u_char	*type)
{
    register u_char *bufp;
    u_long	    asn_length;

    if (!data || !datalength || !type) {
	ERROR_MSG("parse header: NULL pointer");
	return NULL;
    }
    bufp = data;
    /* this only works on data types < 30, i.e. no extension octets */
    if (IS_EXTENSION_ID(*bufp)){
	ERROR_MSG("can't process ID >= 30");
	return NULL;
    }
    *type = *bufp;
    bufp = asn_parse_length(bufp + 1, &asn_length);
    if (_asn_parse_length_check("parse header", bufp, data, asn_length, *datalength))
	return NULL;

    DEBUGDUMPSETUP("dump_recv", data, (bufp-data));
    DEBUGMSG(("dump_recv", "  ASN Header: 0x%.2X, len = %d (0x%X)\n", *data,
              asn_length, asn_length));

#ifdef OPAQUE_SPECIAL_TYPES

    if ((*type == ASN_OPAQUE) &&
        (*bufp == ASN_OPAQUE_TAG1)) {
      DEBUGINDENTMORE();
      DEBUGDUMPSETUP("dump_recv", data, 1);
      DEBUGMSG(("dump_recv", "Opaque:\t%.2x\n", *bufp));
      DEBUGINDENTLESS();

      /* check if 64-but counter */
      switch(*(bufp+1)) {
        case ASN_OPAQUE_COUNTER64:
        case ASN_OPAQUE_U64:
        case ASN_OPAQUE_FLOAT:
        case ASN_OPAQUE_DOUBLE:
        case ASN_OPAQUE_I64:
          *type = *(bufp+1);
          break;
        
        default:
          /* just an Opaque */
          *datalength = (int)asn_length;
          return bufp;
      }
      /* value is encoded as special format */
      bufp = asn_parse_length(bufp + 2, &asn_length);
      if (_asn_parse_length_check("parse opaque header", bufp, data,
                  asn_length, *datalength))
        return NULL;
    }
#endif /* OPAQUE_SPECIAL_TYPES */

    *datalength = (int)asn_length;

    return bufp;
}

/*
 * same as asn_parse_header with test for expected type.
 */
u_char *
asn_parse_sequence(u_char	*data,
		 size_t *datalength,
		 u_char	*type,
		 u_char	expected_type, /* must be this type */
		 const char *estr)	/* error message prefix */
{
    data = asn_parse_header(data, datalength, type);
    if (data && (*type != expected_type)) {
	char ebuf[128];
	sprintf(ebuf, "%s header type %02X: s/b %02X", estr,
			(u_char)*type, (u_char)expected_type);
	ERROR_MSG(ebuf);
	return NULL;
    }
    return data;
}



/*
 * asn_build_header - builds an ASN header for an object with the ID and
 * length specified.
 *  On entry, datalength is input as the number of valid bytes following
 *   "data".  On exit, it is returned as the number of valid bytes
 *   in this object following the id and length.
 *
 *  This only works on data types < 30, i.e. no extension octets.
 *  The maximum length is 0xFFFF;
 *
 *  Returns a pointer to the first byte of the contents of this object.
 *  Returns NULL on any error.

  u_char * asn_build_header(
      u_char     *data         IN - pointer to start of object
      size_t     *datalength   IN/OUT - number of valid bytes left in buffer
      u_char      type         IN - asn type of object
      size_t      length       IN - length of object
 */
u_char *
asn_build_header (u_char *data,
		  size_t *datalength,
		  u_char type,
		  size_t length)
{
    char ebuf[128];
    
    if (*datalength < 1){
	sprintf(ebuf, "bad header length < 1 :%d, %d", *datalength, length);
	ERROR_MSG(ebuf);
	return NULL;
    }	    
    *data++ = type;
    (*datalength)--;
    return asn_build_length(data, datalength, length);
}

/*
 * asn_build_sequence - builds an ASN header for a sequence with the ID and
 * length specified.
 *  On entry, datalength is input as the number of valid bytes following
 *   "data".  On exit, it is returned as the number of valid bytes
 *   in this object following the id and length.
 *
 *  This only works on data types < 30, i.e. no extension octets.
 *  The maximum length is 0xFFFF;
 *
 *  Returns a pointer to the first byte of the contents of this object.
 *  Returns NULL on any error.

  u_char * asn_build_sequence(
      u_char     *data         IN - pointer to start of object
      int        *datalength   IN/OUT - number of valid bytes left in buffer
      u_char      type         IN - asn type of object
      int         length       IN - length of object
 */
u_char *
asn_build_sequence(u_char *data,
		  size_t *datalength,
		  u_char type,
		  size_t length)
{
    static const char *errpre = "build seq";
    char ebuf[128];
    
    if (*datalength < 4){
	sprintf(ebuf, "%s: length %d < 4: PUNT", errpre, (int)*datalength);
	ERROR_MSG(ebuf);
	return NULL;
    }
    *datalength -= 4;
    *data++ = type;
    *data++ = (u_char)(0x02 | ASN_LONG_LEN);
    *data++ = (u_char)((length >> 8) & 0xFF);
    *data++ = (u_char)(length & 0xFF);
    return data;
}

/*
 * asn_parse_length - interprets the length of the current object.
 *  On exit, length contains the value of this length field.
 *
 *  Returns a pointer to the first byte after this length
 *  field (aka: the start of the data field).
 *  Returns NULL on any error.

  u_char * asn_parse_length(
      u_char     *data         IN - pointer to start of length field
      u_long     *length       OUT - value of length field
 */
u_char *
asn_parse_length(u_char  *data,
		 u_long  *length)
{
    static const char *errpre = "parse length";
    char ebuf[128];
    register u_char lengthbyte;
    
    if (!data || !length) {
	ERROR_MSG("parse length: NULL pointer");
	return NULL;
    }
    lengthbyte = *data;

    if (lengthbyte & ASN_LONG_LEN){
	lengthbyte &= ~ASN_LONG_LEN;	/* turn MSb off */
	if (lengthbyte == 0){
	    sprintf(ebuf, "%s: indefinite length not supported", errpre);
	    ERROR_MSG(ebuf);
	    return NULL;
	}
	if (lengthbyte > sizeof(long)){
	    sprintf(ebuf, "%s: data length %d > %d not supported", errpre,
                 lengthbyte, sizeof(long));
	    ERROR_MSG(ebuf);
	    return NULL;
	}
	data++;
	*length = 0;  /* protect against short lengths */
	while(lengthbyte--) {
		*length <<= 8;
		*length |= *data++;
	}
	return data;
    } else { /* short asnlength */
	*length = (long)lengthbyte;
	return data + 1;
    }
}

/*

  u_char * asn_build_length(
      u_char     *data         IN - pointer to start of object
      int        *datalength   IN/OUT - number of valid bytes left in buffer
      int         length       IN - length of object
 */
u_char *
asn_build_length(u_char *data,
		 size_t *datalength,
		 size_t length)
{
    static const char *errpre = "build length";
    char ebuf[128];
    
    u_char    *start_data = data;

    /* no indefinite lengths sent */
    if (length < 0x80){
	if (*datalength < 1){
	    sprintf(ebuf, "%s: bad length < 1 :%d, %d",errpre,*datalength,length);
	    ERROR_MSG(ebuf);
	    return NULL;
	}	    
	*data++ = (u_char)length;
    } else if (length <= 0xFF){
	if (*datalength < 2){
	    sprintf(ebuf, "%s: bad length < 2 :%d, %d",errpre,*datalength,length);
	    ERROR_MSG(ebuf);
	    return NULL;
	}	    
	*data++ = (u_char)(0x01 | ASN_LONG_LEN);
	*data++ = (u_char)length;
    } else { /* 0xFF < length <= 0xFFFF */
	if (*datalength < 3){
	    sprintf(ebuf, "%s: bad length < 3 :%d, %d",errpre,*datalength,length);
	    ERROR_MSG(ebuf);
	    return NULL;
	}	    
	*data++ = (u_char)(0x02 | ASN_LONG_LEN);
	*data++ = (u_char)((length >> 8) & 0xFF);
	*data++ = (u_char)(length & 0xFF);
    }
    *datalength -= (data - start_data);
    return data;

}

/*
 * asn_parse_objid - pulls an object indentifier out of an ASN object identifier type.
 *  On entry, datalength is input as the number of valid bytes following
 *   "data".  On exit, it is returned as the number of valid bytes
 *   following the beginning of the next object.
 *
 *  "objid" is filled with the object identifier.
 *
 *  Returns a pointer to the first byte past the end
 *   of this object (i.e. the start of the next object).
 *  Returns NULL on any error.

  u_char * asn_parse_objid(
      u_char     *data         IN - pointer to start of object
      int        *datalength   IN/OUT - number of valid bytes left in buffer
      u_char     *type         OUT - asn type of object
      oid        *objid        IN/OUT - pointer to start of output buffer
      int        *objidlength  IN/OUT - number of sub-id's in objid
 */
u_char *
asn_parse_objid(u_char *data,
		size_t *datalength,
		u_char *type,	
		oid *objid,
		size_t *objidlength)
{
/*
 * ASN.1 objid ::= 0x06 asnlength subidentifier {subidentifier}*
 * subidentifier ::= {leadingbyte}* lastbyte
 * leadingbyte ::= 1 7bitvalue
 * lastbyte ::= 0 7bitvalue
 */
    register u_char *bufp = data;
    register oid *oidp = objid + 1;
    register u_long subidentifier;
    register long   length;
    u_long	    asn_length;

    *type = *bufp++;
    bufp = asn_parse_length(bufp, &asn_length);
    if (_asn_parse_length_check("parse objid", bufp, data,
                    asn_length, *datalength))
	return NULL;

    *datalength -= (int)asn_length + (bufp - data);

    DEBUGDUMPSETUP("dump_recv", data, bufp - data + asn_length);

    /* Handle invalid object identifier encodings of the form 06 00 robustly */
    if (asn_length == 0)
	objid[0] = objid[1] = 0;

    length = asn_length;
    (*objidlength)--;	/* account for expansion of first byte */

    while (length > 0 && (*objidlength)-- > 0){
	subidentifier = 0;