asn1.c

snmp up 2

}


/*
 * asn_build_null - Builds an ASN null 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
 *   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_null(
 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         *
asn_build_null(u_char * data, size_t * datalength, u_char type)
{
    /*
     * ASN.1 null ::= 0x05 0x00
     */
#ifndef SNMP_NO_DEBUGGING
    u_char         *initdatap = data;
#endif
    data = asn_build_header(data, datalength, type, 0);
    DEBUGDUMPSETUP("send", initdatap, data - initdatap);
    DEBUGMSG(("dumpv_send", "  NULL\n"));
    return data;
}

/*
 * asn_parse_bitstring - pulls a bitstring out of an ASN bitstring 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 bit 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_bitstring(
 u_char     *data         IN - pointer to start of object
 size_t     *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
 size_t     *strlength    IN/OUT - size of output buffer
 */
u_char         *
asn_parse_bitstring(u_char * data,
                    size_t * datalength,
                    u_char * type, u_char * string, size_t * strlength)
{
    /*
     * bitstring ::= 0x03 asnlength unused {byte}*
     */
    static const char *errpre = "parse bitstring";
    register 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 ((size_t) asn_length > *strlength) {
        _asn_length_err(errpre, (size_t) asn_length, *strlength);
        return NULL;
    }
    if (_asn_bitstring_check(errpre, asn_length, *bufp))
        return NULL;

    DEBUGDUMPSETUP("recv", data, bufp - data);
    DEBUGMSG(("dumpv_recv", "  Bitstring: "));
    DEBUGMSGHEX(("dumpv_recv", data, asn_length));
    DEBUGMSG(("dumpv_recv", "\n"));

    memmove(string, bufp, asn_length);
    *strlength = (int) asn_length;
    *datalength -= (int) asn_length + (bufp - data);
    return bufp + asn_length;
}


/*
 * asn_build_bitstring - Builds an ASN bit 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_bitstring(
 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_bitstring(u_char * data,
                    size_t * datalength,
                    u_char type, u_char * string, size_t strlength)
{
    /*
     * ASN.1 bit string ::= 0x03 asnlength unused {byte}*
     */
    static const char *errpre = "build bitstring";
    if (_asn_bitstring_check
        (errpre, strlength, ((string) ? *string : (u_char) 0)))
        return NULL;

    data = asn_build_header(data, datalength, type, strlength);
    if (_asn_build_header_check(errpre, data, *datalength, strlength))
        return NULL;

    if (strlength > 0 && string)
        memmove(data, string, strlength);
    else if (strlength > 0 && !string) {
        ERROR_MSG("no string passed into asn_build_bitstring\n");
        return NULL;
    }

    *datalength -= strlength;
    DEBUGDUMPSETUP("send", data, strlength);
    DEBUGMSG(("dumpv_send", "  Bitstring: "));
    DEBUGMSGHEX(("dumpv_send", data, strlength));
    DEBUGMSG(("dumpv_send", "\n"));
    return data + strlength;
}

/*
 * asn_parse_unsigned_int64 - pulls a 64 bit unsigned long out of an ASN int
 * 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 end of this 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_parse_unsigned_int64(
 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
 struct counter64 *cp     IN/OUT - pointer to counter struct
 int         countersize  IN - size of output buffer
 */
u_char         *
asn_parse_unsigned_int64(u_char * data,
                         size_t * datalength,
                         u_char * type,
                         struct counter64 * cp, size_t countersize)
{
    /*
     * ASN.1 integer ::= 0x02 asnlength byte {byte}*
     */
    static const char *errpre = "parse uint64";
    const int       uint64sizelimit = (4 * 2) + 1;
    register u_char *bufp = data;
    u_long          asn_length;
    register u_long low = 0, high = 0;

    if (countersize != sizeof(struct counter64)) {
        _asn_size_err(errpre, countersize, sizeof(struct counter64));
        return NULL;
    }
    *type = *bufp++;
    bufp = asn_parse_length(bufp, &asn_length);
    if (_asn_parse_length_check
        (errpre, bufp, data, asn_length, *datalength))
        return NULL;

    DEBUGDUMPSETUP("recv", data, bufp - data);
#ifdef OPAQUE_SPECIAL_TYPES
    /*
     * 64 bit counters as opaque 
     */
    if ((*type == ASN_OPAQUE) &&
        (asn_length <= ASN_OPAQUE_COUNTER64_MX_BER_LEN) &&
        (*bufp == ASN_OPAQUE_TAG1) &&
        ((*(bufp + 1) == ASN_OPAQUE_COUNTER64) ||
         (*(bufp + 1) == ASN_OPAQUE_U64))) {
        /*
         * change type to Counter64 or U64 
         */
        *type = *(bufp + 1);
        /*
         * value is encoded as special format 
         */
        bufp = asn_parse_length(bufp + 2, &asn_length);
        if (_asn_parse_length_check("parse opaque uint64", bufp, data,
                                    asn_length, *datalength))
            return NULL;
    }
#endif                          /* OPAQUE_SPECIAL_TYPES */
    if (((int) asn_length > uint64sizelimit) ||
        (((int) asn_length == uint64sizelimit) && *bufp != 0x00)) {
        _asn_length_err(errpre, (size_t) asn_length, uint64sizelimit);
        return NULL;
    }
    *datalength -= (int) asn_length + (bufp - data);
    if (*bufp & 0x80) {
        low = ~low;             /* integer is negative */
        high = ~high;
    }

    while (asn_length--) {
        high = (high << 8) | ((low & 0xFF000000) >> 24);
        low = (low << 8) | *bufp++;
    }

    cp->low = low;
    cp->high = high;

    DEBUGIF("dumpv_recv") {
        char            i64buf[I64CHARSZ + 1];
        printU64(i64buf, cp);
        DEBUGMSG(("dumpv_recv", "Counter64: ", i64buf));
    }

    return bufp;
}


/*
 * asn_build_unsigned_int64 - builds an ASN object containing a 64 bit integer.
 *  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 end of this 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_unsigned_int64(
 u_char     *data         IN - pointer to start of output buffer
 size_t     *datalength   IN/OUT - number of valid bytes left in buffer
 u_char      type         IN  - asn type of object
 struct counter64 *cp     IN - pointer to counter struct
 size_t      countersize  IN - size of input buffer
 */
u_char         *
asn_build_unsigned_int64(u_char * data,
                         size_t * datalength,
                         u_char type,
                         struct counter64 * cp, size_t countersize)
{
    /*
     * ASN.1 integer ::= 0x02 asnlength byte {byte}*
     */

    register u_long low, high;
    register u_long mask, mask2;
    int             add_null_byte = 0;
    size_t          intsize;
#ifndef SNMP_NO_DEBUGGING
    u_char         *initdatap = data;
#endif

    if (countersize != sizeof(struct counter64)) {
        _asn_size_err("build uint64", countersize,
                      sizeof(struct counter64));
        return NULL;
    }
    intsize = 8;
    low = cp->low;
    high = cp->high;
    mask = ((u_long) 0xFF) << (8 * (sizeof(long) - 1));
    /*
     * mask is 0xFF000000 on a big-endian machine 
     */
    if ((u_char) ((high & 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.
         */
        mask2 = ((u_long) 0x1FF) << ((8 * (sizeof(long) - 1)) - 1);
        /*
         * mask2 is 0xFF800000 on a big-endian machine 
         */
        while ((((high & mask2) == 0) || ((high & mask2) == mask2))
               && intsize > 1) {
            intsize--;
            high = (high << 8)
                | ((low & mask) >> (8 * (sizeof(long) - 1)));
            low <<= 8;
        }
    }
#ifdef OPAQUE_SPECIAL_TYPES
    /*
     * encode a Counter64 as an opaque (it also works in SNMPv1) 
     */
    /*
     * turn into Opaque holding special tagged value 
     */
    if (type == ASN_OPAQUE_COUNTER64) {
        /*
         * put the tag and length for the Opaque wrapper 
         */
        data = asn_build_header(data, datalength, ASN_OPAQUE, intsize + 3);
        if (_asn_build_header_check
            ("build counter u64", data, *datalength, intsize + 3))
            return NULL;

        /*
         * put the special tag and length 
         */
        *data++ = ASN_OPAQUE_TAG1;
        *data++ = ASN_OPAQUE_COUNTER64;
        *data++ = (u_char) intsize;
        *datalength = *datalength - 3;
    } else
        /*
         * Encode the Unsigned int64 in an opaque 
         */
        /*
         * turn into Opaque holding special tagged value 
         */
    if (type == ASN_OPAQUE_U64) {
        /*
         * put the tag and length for the Opaque wrapper 
         */
        data = asn_build_header(data, datalength, ASN_OPAQUE, intsize + 3);
        if (_asn_build_header_check
            ("build opaque u64", data, *datalength, intsize + 3))
            return NULL;

        /*
         * put the special tag and length 
         */
        *data++ = ASN_OPAQUE_TAG1;
        *data++ = ASN_OPAQUE_U64;
        *data++ = (u_char) intsize;
        *datalength = *datalength - 3;
    } else {
#endif                          /* OPAQUE_SPECIAL_TYPES */
        data = asn_build_header(data, datalength, type, intsize);
        if (_asn_build_header_check
            ("build uint64", data, *datalength, intsize))
            return NULL;

#ifdef OPAQUE_SPECIAL_TYPES
    }
#endif                          /* OPAQUE_SPECIAL_TYPES */
    *datalength -= intsize;
    if (add_null_byte == 1) {
        *data++ = '\0';
        intsize--;
    }
    while (intsize--) {
        *data++ = (u_char) ((high & mask) >> (8 * (sizeof(long) - 1)));
        high = (high << 8)
            | ((low & mask) >> (8 * (sizeof(long) - 1)));
        low <<= 8;

    }
    DEBUGDUMPSETUP("send", initdatap, data - initdatap);
    DEBUGIF("dumpv_send") {
        char            i64buf[I64CHARSZ + 1];
        printU64(i64buf, cp);
        DEBUGMSG(("dumpv_send", i64buf));
    }
    return data;
}

#ifdef OPAQUE_SPECIAL_TYPES

/*
 * 
 * u_char * asn_parse_signed_int64(
 * 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
 * struct counter64 *cp     IN/OUT - pointer to counter struct
 * int         countersize  IN - size of output buffer
 */

u_char         *
asn_parse_signed_int64(u_char * data,
                       size_t * datalength,
                       u_char * type,
                       struct counter64 * cp, size_t countersize)
{
    static const char *errpre = "parse int64";
    const int       int64sizelimit = (4 * 2) + 1;
    char            ebuf[128];
    register u_char *bufp = data;
    u_long          asn_length;
    register u_int  low = 0, high = 0;

    if (countersize != sizeof(struct counter64)) {
        _asn_size_err(errpre, countersize, sizeof(struct counter64));
        return NULL;
    }
    *type = *bufp++;
    bufp = asn_parse_length(bufp, &asn_length);
    if (_asn_parse_length_check
        (errpre, bufp, data, asn_length, *datalength))
        return NULL;

    DEBUGDUMPSETUP("recv", data, bufp - data);
    if ((*type == ASN_OPAQUE) &&
        (asn_length <= ASN_OPAQUE_COUNTER64_MX_BER_LEN) &&
        (*bufp == ASN_OPAQUE_TAG1) && (*(bufp + 1) == ASN_OPAQUE_I64)) {
        /*
         * change type to Int64 
         */
        *type = *(bufp + 1);
        /*