krb5/asn.1/asn1_make.c

/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 * src/lib/krb5/asn.1/asn1_make.c
 *
 * Copyright 1994 by the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */

#include "asn1_make.h"

asn1_error_code
asn1_make_etag(asn1buf *buf, asn1_class asn1class, asn1_tagnum tagnum,
               unsigned int in_len, unsigned int *retlen)
{
    return asn1_make_tag(buf,asn1class,CONSTRUCTED,tagnum,in_len,retlen);
}

asn1_error_code
asn1_make_tag(asn1buf *buf, asn1_class asn1class,
              asn1_construction construction, asn1_tagnum tagnum,
              unsigned int in_len, unsigned int *retlen)
{
    asn1_error_code retval;
    unsigned int sumlen=0, length;

    if (tagnum > ASN1_TAGNUM_MAX) return ASN1_OVERFLOW;

    retval = asn1_make_length(buf,in_len, &length);
    if (retval) return retval;
    sumlen += length;
    retval = asn1_make_id(buf,asn1class,construction,tagnum,&length);
    if (retval) return retval;
    sumlen += length;

    *retlen = sumlen;
    return 0;
}

asn1_error_code
asn1_make_length(asn1buf *buf, const unsigned int in_len, unsigned int *retlen)
{
    asn1_error_code retval;

    if (in_len < 128) {
        retval = asn1buf_insert_octet(buf, (asn1_octet)(in_len&0x7F));
        if (retval) return retval;
        *retlen = 1;
    } else {
        int in_copy=in_len, length=0;

        while (in_copy != 0) {
            retval = asn1buf_insert_octet(buf, (asn1_octet)(in_copy&0xFF));
            if (retval) return retval;
            in_copy = in_copy >> 8;
            length++;
        }
        retval = asn1buf_insert_octet(buf, (asn1_octet) (0x80 | (asn1_octet)(length&0x7F)));
        if (retval) return retval;
        length++;
        *retlen = length;
    }

    return 0;
}

asn1_error_code
asn1_make_id(asn1buf *buf, asn1_class asn1class,
             asn1_construction construction, asn1_tagnum tagnum,
             unsigned int *retlen)
{
    asn1_error_code retval;

    if (tagnum < 31) {
        retval = asn1buf_insert_octet(buf, (asn1_octet) (asn1class | construction |
                                                         (asn1_octet)tagnum));
        if (retval) return retval;
        *retlen = 1;
    } else {
        asn1_tagnum tagcopy = tagnum;
        int length = 0;

        retval = asn1buf_insert_octet(buf, (asn1_octet)(tagcopy&0x7F));
        if (retval) return retval;
        tagcopy >>= 7;
        length++;

        for (; tagcopy != 0; tagcopy >>= 7) {
            retval = asn1buf_insert_octet(buf, (asn1_octet) (0x80 | (asn1_octet)(tagcopy&0x7F)));
            if (retval) return retval;
            length++;
        }

        retval = asn1buf_insert_octet(buf, (asn1_octet) (asn1class | construction | 0x1F));
        if (retval) return retval;
        length++;
        *retlen = length;
    }

    return 0;
}

asn1_error_code
asn1_make_sequence(asn1buf *buf, const unsigned int seq_len,
                   unsigned int *retlen)
{
    asn1_error_code retval;
    unsigned int len, sum=0;

    retval = asn1_make_length(buf,seq_len,&len);
    if (retval) return retval;
    sum += len;
    retval = asn1_make_id(buf,UNIVERSAL,CONSTRUCTED,ASN1_SEQUENCE,&len);
    if (retval) return retval;
    sum += len;

    *retlen = sum;
    return 0;
}

asn1_error_code
asn1_make_set(asn1buf *buf, const unsigned int set_len, unsigned int *retlen)
{
    asn1_error_code retval;
    unsigned int len, sum=0;

    retval = asn1_make_length(buf,set_len,&len);
    if (retval) return retval;
    sum += len;
    retval = asn1_make_id(buf,UNIVERSAL,CONSTRUCTED,ASN1_SET,&len);
    if (retval) return retval;
    sum += len;

    *retlen = sum;
    return 0;
}

asn1_error_code
asn1_make_string(asn1buf *buf, const unsigned int length, const char *string,
                 int *retlen)
{
    asn1_error_code retval;

    retval = asn1buf_insert_charstring(buf,length,string);
    if (retval) return retval;

    *retlen = length;
    return 0;
}