/* crypto/asn1/a_int.c */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 *

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 *

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 *

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.]

 */

#include <stdio.h>

#include "cryptlib.h"

#include <openssl/asn1.h>

#include <openssl/bn.h>

ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)

{

    return M_ASN1_INTEGER_dup(x);

}

int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)

{

    int neg, ret;

    /* Compare signs */

    neg = x->type & V_ASN1_NEG;

    if (neg != (y->type & V_ASN1_NEG)) {

        if (neg)

            return -1;

        else

            return 1;

    }

    ret = ASN1_STRING_cmp(x, y);

    if (neg)

        return -ret;

    else

        return ret;

}

/*-

 * This converts an ASN1 INTEGER into its content encoding.

 * The internal representation is an ASN1_STRING whose data is a big endian

 * representation of the value, ignoring the sign. The sign is determined by

 * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.

 *

 * Positive integers are no problem: they are almost the same as the DER

 * encoding, except if the first byte is >= 0x80 we need to add a zero pad.

 *

 * Negative integers are a bit trickier...

 * The DER representation of negative integers is in 2s complement form.

 * The internal form is converted by complementing each octet and finally

 * adding one to the result. This can be done less messily with a little trick.

 * If the internal form has trailing zeroes then they will become FF by the

 * complement and 0 by the add one (due to carry) so just copy as many trailing

 * zeros to the destination as there are in the source. The carry will add one

 * to the last none zero octet: so complement this octet and add one and finally

 * complement any left over until you get to the start of the string.

 *

 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad

 * with 0xff. However if the first byte is 0x80 and one of the following bytes

 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80

 * followed by optional zeros isn't padded.

 */

int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)

{

    int pad = 0, ret, i, neg;

    unsigned char *p, *n, pb = 0;

    if (a == NULL)

        return (0);

    neg = a->type & V_ASN1_NEG;

    if (a->length == 0)

        ret = 1;

    else {

        ret = a->length;

        i = a->data[0];

        if (ret == 1 && i == 0)

            neg = 0;

        if (!neg && (i > 127)) {

            pad = 1;

            pb = 0;

        } else if (neg) {

            if (i > 128) {

                pad = 1;

                pb = 0xFF;

            } else if (i == 128) {

                /*

                 * Special case: if any other bytes non zero we pad:

                 * otherwise we don't.

                 */

                for (i = 1; i < a->length; i++)

                    if (a->data[i]) {

                        pad = 1;

                        pb = 0xFF;

                        break;

                    }

            }

        }

        ret += pad;

    }

    if (pp == NULL)

        return (ret);

    p = *pp;

    if (pad)

        *(p++) = pb;

    if (a->length == 0)

        *(p++) = 0;

    else if (!neg)

        memcpy(p, a->data, (unsigned int)a->length);

    else {

        /* Begin at the end of the encoding */

        n = a->data + a->length - 1;

        p += a->length - 1;

        i = a->length;

        /* Copy zeros to destination as long as source is zero */

        while (!*n && i > 1) {

            *(p--) = 0;

            n--;

            i--;

        }

        /* Complement and increment next octet */

        *(p--) = ((*(n--)) ^ 0xff) + 1;

        i--;

        /* Complement any octets left */

        for (; i > 0; i--)

            *(p--) = *(n--) ^ 0xff;

    }

    *pp += ret;

    return (ret);

}

/* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */

ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,

                               long len)

{

    ASN1_INTEGER *ret = NULL;

    const unsigned char *p, *pend;

    unsigned char *to, *s;

    int i;

    if ((a == NULL) || ((*a) == NULL)) {

        if ((ret = M_ASN1_INTEGER_new()) == NULL)

            return (NULL);

        ret->type = V_ASN1_INTEGER;

    } else

        ret = (*a);

    p = *pp;

    pend = p + len;

    /*

     * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies

     * a missing NULL parameter.

     */

    s = (unsigned char *)OPENSSL_malloc((int)len + 1);

    if (s == NULL) {

        i = ERR_R_MALLOC_FAILURE;

        goto err;

    }

    to = s;

    if (!len) {

        /*

         * Strictly speaking this is an illegal INTEGER but we tolerate it.

         */

        ret->type = V_ASN1_INTEGER;

    } else if (*p & 0x80) {     /* a negative number */

        ret->type = V_ASN1_NEG_INTEGER;

        if ((*p == 0xff) && (len != 1)) {

            p++;

            len--;

        }

        i = len;

        p += i - 1;

        to += i - 1;

        while ((!*p) && i) {

            *(to--) = 0;

            i--;

            p--;

        }

        /*

         * Special case: if all zeros then the number will be of the form FF

         * followed by n zero bytes: this corresponds to 1 followed by n zero

         * bytes. We've already written n zeros so we just append an extra

         * one and set the first byte to a 1. This is treated separately

         * because it is the only case where the number of bytes is larger

         * than len.

         */

        if (!i) {

            *s = 1;

            s[len] = 0;

            len++;

        } else {

            *(to--) = (*(p--) ^ 0xff) + 1;

            i--;

            for (; i > 0; i--)

                *(to--) = *(p--) ^ 0xff;

        }

    } else {

        ret->type = V_ASN1_INTEGER;

        if ((*p == 0) && (len != 1)) {

            p++;

            len--;

        }

        memcpy(s, p, (int)len);

    }

    if (ret->data != NULL)

        OPENSSL_free(ret->data);

    ret->data = s;

    ret->length = (int)len;

    if (a != NULL)

        (*a) = ret;

    *pp = pend;

    return (ret);

 err:

    ASN1err(ASN1_F_C2I_ASN1_INTEGER, i);

    if ((ret != NULL) && ((a == NULL) || (*a != ret)))

        M_ASN1_INTEGER_free(ret);

    return (NULL);

}

/*

 * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1

 * integers: some broken software can encode a positive INTEGER with its MSB

 * set as negative (it doesn't add a padding zero).

 */

ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,

                                long length)

{

    ASN1_INTEGER *ret = NULL;

    const unsigned char *p;

    unsigned char *s;

    long len;

    int inf, tag, xclass;

    int i;

    if ((a == NULL) || ((*a) == NULL)) {

        if ((ret = M_ASN1_INTEGER_new()) == NULL)

            return (NULL);

        ret->type = V_ASN1_INTEGER;

    } else

        ret = (*a);

    p = *pp;

    inf = ASN1_get_object(&p, &len, &tag, &xclass, length);

    if (inf & 0x80) {

        i = ASN1_R_BAD_OBJECT_HEADER;

        goto err;

    }

    if (tag != V_ASN1_INTEGER) {

        i = ASN1_R_EXPECTING_AN_INTEGER;

        goto err;

    }

    /*

     * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies

     * a missing NULL parameter.

     */

    s = (unsigned char *)OPENSSL_malloc((int)len + 1);

    if (s == NULL) {

        i = ERR_R_MALLOC_FAILURE;

        goto err;

    }

    ret->type = V_ASN1_INTEGER;

    if (len) {

        if ((*p == 0) && (len != 1)) {

            p++;

            len--;

        }

        memcpy(s, p, (int)len);

        p += len;

    }

    if (ret->data != NULL)

        OPENSSL_free(ret->data);

    ret->data = s;

    ret->length = (int)len;

    if (a != NULL)

        (*a) = ret;

    *pp = p;

    return (ret);

 err:

    ASN1err(ASN1_F_D2I_ASN1_UINTEGER, i);

    if ((ret != NULL) && ((a == NULL) || (*a != ret)))

        M_ASN1_INTEGER_free(ret);

    return (NULL);

}

int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)

{

    int j, k;

    unsigned int i;

    unsigned char buf[sizeof(long) + 1];

    long d;

    a->type = V_ASN1_INTEGER;

    if (a->length < (int)(sizeof(long) + 1)) {

        if (a->data != NULL)

            OPENSSL_free(a->data);

        if ((a->data =

             (unsigned char *)OPENSSL_malloc(sizeof(long) + 1)) != NULL)

            memset((char *)a->data, 0, sizeof(long) + 1);

    }

    if (a->data == NULL) {

        ASN1err(ASN1_F_ASN1_INTEGER_SET, ERR_R_MALLOC_FAILURE);

        return (0);

    }

    d = v;

    if (d < 0) {

        d = -d;

        a->type = V_ASN1_NEG_INTEGER;

    }

    for (i = 0; i < sizeof(long); i++) {

        if (d == 0)

            break;

        buf[i] = (int)d & 0xff;

        d >>= 8;

    }

    j = 0;

    for (k = i - 1; k >= 0; k--)

        a->data[j++] = buf[k];

    a->length = j;

    return (1);

}

long ASN1_INTEGER_get(const ASN1_INTEGER *a)

{

    int neg = 0, i;

    long r = 0;

    if (a == NULL)

        return (0L);

    i = a->type;

    if (i == V_ASN1_NEG_INTEGER)

        neg = 1;

    else if (i != V_ASN1_INTEGER)

        return -1;

    if (a->length > (int)sizeof(long)) {

        /* hmm... a bit ugly, return all ones */

        return -1;

    }

    if (a->data == NULL)

        return 0;

    for (i = 0; i < a->length; i++) {

        r <<= 8;

        r |= (unsigned char)a->data[i];

    }

    if (neg)

        r = -r;

    return (r);

}

ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)

{

    ASN1_INTEGER *ret;

    int len, j;

    if (ai == NULL)

        ret = M_ASN1_INTEGER_new();

    else

        ret = ai;

    if (ret == NULL) {

        ASN1err(ASN1_F_BN_TO_ASN1_INTEGER, ERR_R_NESTED_ASN1_ERROR);

        goto err;

    }

    if (BN_is_negative(bn) && !BN_is_zero(bn))

        ret->type = V_ASN1_NEG_INTEGER;

    else

        ret->type = V_ASN1_INTEGER;

    j = BN_num_bits(bn);

    len = ((j == 0) ? 0 : ((j / 8) + 1));

    if (ret->length < len + 4) {

        unsigned char *new_data = OPENSSL_realloc(ret->data, len + 4);

        if (!new_data) {

            ASN1err(ASN1_F_BN_TO_ASN1_INTEGER, ERR_R_MALLOC_FAILURE);

            goto err;

        }

        ret->data = new_data;

    }

    ret->length = BN_bn2bin(bn, ret->data);

    /* Correct zero case */

    if (!ret->length) {

        ret->data[0] = 0;

        ret->length = 1;

    }

    return (ret);

 err:

    if (ret != ai)

        M_ASN1_INTEGER_free(ret);

    return (NULL);

}

BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)

{

    BIGNUM *ret;

    if ((ret = BN_bin2bn(ai->data, ai->length, bn)) == NULL)

        ASN1err(ASN1_F_ASN1_INTEGER_TO_BN, ASN1_R_BN_LIB);

    else if (ai->type == V_ASN1_NEG_INTEGER)

        BN_set_negative(ret, 1);

    return (ret);

}

IMPLEMENT_STACK_OF(ASN1_INTEGER)

IMPLEMENT_ASN1_SET_OF(ASN1_INTEGER)