/*
* asn1_decode_maybe_unsigned
*
* This is needed because older releases of MIT krb5 have signed
* sequence numbers. We want to accept both signed and unsigned
* sequence numbers, in the range -2^31..2^32-1, mapping negative
* numbers into their positive equivalents in the same way that C's
* normal integer conversions do, i.e., would preserve bits on a
* two's-complement architecture.
*/
asn1_error_code asn1_decode_maybe_unsigned(asn1buf *buf, unsigned long *val)
{
setup();
asn1_octet o;
unsigned long n, bitsremain;
unsigned int i;
tag(ASN1_INTEGER);
o = 0;
n = 0;
bitsremain = ~0UL;
for (i = 0; i < length; i++) {
/* Accounts for u_long width not being a multiple of 8. */
if (bitsremain < 0xff) return ASN1_OVERFLOW;
retval = asn1buf_remove_octet(buf, &o);
if (retval) return retval;
if (bitsremain == ~0UL) {
if (i == 0)
n = (o & 0x80) ? ~0UL : 0UL; /* grab sign bit */
/*
* Skip leading zero or 0xFF octets to humor non-compliant encoders.
*/
if (n == 0 && o == 0)
continue;
if (n == ~0UL && o == 0xff)
continue;
}
n = (n << 8) | o;
bitsremain >>= 8;
}
*val = n;
cleanup();
}
asn1_error_code
asn1_decode_integer(asn1buf *buf, long int *val)
{
setup();
asn1_octet o;
long n = 0; /* initialize to keep gcc happy */
unsigned int i;
tag(ASN1_INTEGER);
for (i = 0; i < length; i++) {
retval = asn1buf_remove_octet(buf, &o);
if (retval) return retval;
if (!i) {
n = (0x80 & o) ? -1 : 0; /* grab sign bit */
if (n < 0 && length > sizeof (long))
return ASN1_OVERFLOW;
else if (length > sizeof (long) + 1) /* allow extra octet for positive */
return ASN1_OVERFLOW;
}
n = (n << 8) | o;
}
*val = n;
cleanup();
}
asn1_error_code asn1_decode_boolean(asn1buf *buf, unsigned *val)
{
setup();
asn1_octet bval;
tag(ASN1_BOOLEAN);
retval = asn1buf_remove_octet(buf, &bval);
if (retval) return retval;
*val = (bval != 0x00);
cleanup();
}
asn1_error_code asn1_decode_unsigned_integer(asn1buf *buf, long unsigned int *val)
{
setup();
asn1_octet o;
unsigned long n;
unsigned int i;
tag(ASN1_INTEGER);
for (i = 0, n = 0; i < length; i++) {
retval = asn1buf_remove_octet(buf, &o);
if (retval) return retval;
if (!i) {
if (0x80 & o)
return ASN1_OVERFLOW;
else if (length > sizeof (long) + 1)
return ASN1_OVERFLOW;
}
n = (n << 8) | o;
}
*val = n;
cleanup();
}
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;
}
