a_bitstr.c

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/* crypto/asn1/a_bitstr.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>

int ASN1_BIT_STRING_set(ASN1_BIT_STRING *x, unsigned char *d, int len)
{ return M_ASN1_BIT_STRING_set(x, d, len); }

int i2c_ASN1_BIT_STRING(ASN1_BIT_STRING *a, unsigned char **pp)
    {
    int ret,j,bits,len;
    unsigned char *p,*d;

    if (a == NULL) return(0);

    len=a->length;

    if (len > 0)
        {
        if (a->flags & ASN1_STRING_FLAG_BITS_LEFT)
            {
            bits=(int)a->flags&0x07;
            }
        else
            {
            for ( ; len > 0; len--)
                {
                if (a->data[len-1]) break;
                }
            j=a->data[len-1];
            if      (j & 0x01) bits=0;
            else if (j & 0x02) bits=1;
            else if (j & 0x04) bits=2;
            else if (j & 0x08) bits=3;
            else if (j & 0x10) bits=4;
            else if (j & 0x20) bits=5;
            else if (j & 0x40) bits=6;
            else if (j & 0x80) bits=7;
            else bits=0; /* should not happen */
            }
        }
    else
        bits=0;

    ret=1+len;
    if (pp == NULL) return(ret);

    p= *pp;

    *(p++)=(unsigned char)bits;
    d=a->data;
    memcpy(p,d,len);
    p+=len;
    if (len > 0) p[-1]&=(0xff<<bits);
    *pp=p;
    return(ret);
    }

ASN1_BIT_STRING *c2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a,
    const unsigned char **pp, long len)
    {
    ASN1_BIT_STRING *ret=NULL;
    const unsigned char *p;
    unsigned char *s;
    int i;

    if (len < 1)
        {
        i=ASN1_R_STRING_TOO_SHORT;
        goto err;
        }

    if ((a == NULL) || ((*a) == NULL))
        {
        if ((ret=M_ASN1_BIT_STRING_new()) == NULL) return(NULL);
        }
    else
        ret=(*a);

    p= *pp;
    i= *(p++);
    /* We do this to preserve the settings.  If we modify
     * the settings, via the _set_bit function, we will recalculate
     * on output */
    ret->flags&= ~(ASN1_STRING_FLAG_BITS_LEFT|0x07); /* clear */
    ret->flags|=(ASN1_STRING_FLAG_BITS_LEFT|(i&0x07)); /* set */

    if (len-- > 1) /* using one because of the bits left byte */
        {
        s=(unsigned char *)OPENSSL_malloc((int)len);
        if (s == NULL)
            {
            i=ERR_R_MALLOC_FAILURE;
            goto err;
            }
        memcpy(s,p,(int)len);
        s[len-1]&=(0xff<<i);
        p+=len;
        }
    else
        s=NULL;

    ret->length=(int)len;
    if (ret->data != NULL) OPENSSL_free(ret->data);
    ret->data=s;
    ret->type=V_ASN1_BIT_STRING;
    if (a != NULL) (*a)=ret;
    *pp=p;
    return(ret);
err:
    ASN1err(ASN1_F_C2I_ASN1_BIT_STRING,i);
    if ((ret != NULL) && ((a == NULL) || (*a != ret)))
        M_ASN1_BIT_STRING_free(ret);
    return(NULL);
    }

/* These next 2 functions from Goetz Babin-Ebell <[email protected]>
 */
int ASN1_BIT_STRING_set_bit(ASN1_BIT_STRING *a, int n, int value)
    {
    int w,v,iv;
    unsigned char *c;

    w=n/8;
    v=1<<(7-(n&0x07));
    iv= ~v;
    if (!value) v=0;

    if (a == NULL)
        return 0;

    a->flags&= ~(ASN1_STRING_FLAG_BITS_LEFT|0x07); /* clear, set on write */

    if ((a->length < (w+1)) || (a->data == NULL))
        {
        if (!value) return(1); /* Don't need to set */
        if (a->data == NULL)
            c=(unsigned char *)OPENSSL_malloc(w+1);
        else
            c=(unsigned char *)OPENSSL_realloc_clean(a->data,
                                 a->length,
                                 w+1);
        if (c == NULL)
            {
            ASN1err(ASN1_F_ASN1_BIT_STRING_SET_BIT,ERR_R_MALLOC_FAILURE);
            return 0;
            }
        if (w+1-a->length > 0) memset(c+a->length, 0, w+1-a->length);
        a->data=c;
        a->length=w+1;
    }
    a->data[w]=((a->data[w])&iv)|v;
    while ((a->length > 0) && (a->data[a->length-1] == 0))
        a->length--;
    return(1);
    }

int ASN1_BIT_STRING_get_bit(ASN1_BIT_STRING *a, int n)
    {
    int w,v;

    w=n/8;
    v=1<<(7-(n&0x07));
    if ((a == NULL) || (a->length < (w+1)) || (a->data == NULL))
        return(0);
    return((a->data[w]&v) != 0);
    }

/*
 * Checks if the given bit string contains only bits specified by 
 * the flags vector. Returns 0 if there is at least one bit set in 'a'
 * which is not specified in 'flags', 1 otherwise.
 * 'len' is the length of 'flags'.
 */
int ASN1_BIT_STRING_check(ASN1_BIT_STRING *a,
              unsigned char *flags, int flags_len)
    {
    int i, ok;
    /* Check if there is one bit set at all. */
    if (!a || !a->data) return 1;

    /* Check each byte of the internal representation of the bit string. */
    ok = 1;
    for (i = 0; i < a->length && ok; ++i)
        {
        unsigned char mask = i < flags_len ? ~flags[i] : 0xff;
        /* We are done if there is an unneeded bit set. */
        ok = (a->data[i] & mask) == 0;
        }
    return ok;
    }