src/crypto/asn1/a_bitstr.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 <openssl/asn1.h>

#include <string.h>

#include <openssl/err.h>
#include <openssl/mem.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 padding;

	if (len < 1)
		{
		OPENSSL_PUT_ERROR(ASN1, c2i_ASN1_BIT_STRING,
			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;
	padding = *(p++);
	if (padding > 7)
		{
		OPENSSL_PUT_ERROR(ASN1, c2i_ASN1_BIT_STRING,
			ASN1_R_INVALID_BIT_STRING_BITS_LEFT);
		goto err;
		}

	/* 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|padding); /* set */

	if (len-- > 1) /* using one because of the bits left byte */
		{
		s=(unsigned char *)OPENSSL_malloc((int)len);
		if (s == NULL)
			{
			OPENSSL_PUT_ERROR(ASN1, c2i_ASN1_BIT_STRING,
				ERR_R_MALLOC_FAILURE);
			goto err;
			}
		memcpy(s,p,(int)len);
		s[len-1]&=(0xff<<padding);
		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:
	if ((ret != NULL) && ((a == NULL) || (*a != ret)))
		M_ASN1_BIT_STRING_free(ret);
	return(NULL);
	}

/* These next 2 functions from Goetz Babin-Ebell <babinebell@trustcenter.de>
 */
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)
			{
			OPENSSL_PUT_ERROR(ASN1, 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;
	}