Esempio n. 1
0
/*
 * 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();
}
Esempio n. 2
0
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();
}
Esempio n. 3
0
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();
}
Esempio n. 4
0
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();
}
Esempio n. 5
0
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;
}