a_int.c

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/* crypto/asn1/a_int.c */
/* Copyright (C) 1995-1998 Eric Young ([email protected])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([email protected]).
 * 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 ([email protected]).
 * 
 * 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 ([email protected])"
 *    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 ([email protected])"
 * 
 * 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) || (a->data == NULL)) return(0);
    neg=a->type & V_ASN1_NEG;
    if (a->length == 0)
        ret=1;
    else
        {
        ret=a->length;
        i=a->data[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) {
            *(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))
        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)