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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
* src/lib/krb5/asn.1/asn1_get.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_get.h"
asn1_error_code
asn1_get_tag_2(asn1buf *buf, taginfo *t)
{
asn1_error_code retval;
if (buf == NULL || buf->base == NULL ||
buf->bound - buf->next + 1 <= 0) {
t->tagnum = ASN1_TAGNUM_CEILING; /* emphatically not an EOC tag */
t->asn1class = UNIVERSAL;
t->construction = PRIMITIVE;
t->length = 0;
t->indef = 0;
return 0;
}
{
/* asn1_get_id(buf, t) */
asn1_tagnum tn=0;
asn1_octet o;
#define ASN1_CLASS_MASK 0xC0
#define ASN1_CONSTRUCTION_MASK 0x20
#define ASN1_TAG_NUMBER_MASK 0x1F
retval = asn1buf_remove_octet(buf,&o);
if (retval)
return retval;
t->asn1class = (asn1_class)(o&ASN1_CLASS_MASK);
t->construction = (asn1_construction)(o&ASN1_CONSTRUCTION_MASK);
if ((o&ASN1_TAG_NUMBER_MASK) != ASN1_TAG_NUMBER_MASK) {
/* low-tag-number form */
t->tagnum = (asn1_tagnum)(o&ASN1_TAG_NUMBER_MASK);
} else {
/* high-tag-number form */
do {
retval = asn1buf_remove_octet(buf,&o);
if (retval) return retval;
tn = (tn<<7) + (asn1_tagnum)(o&0x7F);
} while (o&0x80);
t->tagnum = tn;
}
}
{
/* asn1_get_length(buf, t) */
asn1_octet o;
t->indef = 0;
retval = asn1buf_remove_octet(buf,&o);
if (retval) return retval;
if ((o&0x80) == 0) {
t->length = (int)(o&0x7F);
} else {
int num;
int len=0;
for (num = (int)(o&0x7F); num>0; num--) {
retval = asn1buf_remove_octet(buf,&o);
if (retval) return retval;
len = (len<<8) + (int)o;
}
if (len < 0)
return ASN1_OVERRUN;
if (!len)
t->indef = 1;
t->length = len;
}
}
if (t->indef && t->construction != CONSTRUCTED)
return ASN1_MISMATCH_INDEF;
return 0;
}
asn1_error_code
asn1_get_sequence(asn1buf *buf, unsigned int *retlen, int *indef)
{
taginfo t;
asn1_error_code retval;
retval = asn1_get_tag_2(buf, &t);
if (retval)
return retval;
if (t.asn1class != UNIVERSAL || t.construction != CONSTRUCTED ||
t.tagnum != ASN1_SEQUENCE)
return ASN1_BAD_ID;
if (retlen)
*retlen = t.length;
if (indef)
*indef = t.indef;
return 0;
}
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