openssl/crypto/asn1/x_long.c

/* x_long.c */
/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
 * project 2000.
 */
/* ====================================================================
 * Copyright (c) 2000 The OpenSSL Project.  All rights reserved.
 *
 * 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 above 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 acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/asn1t.h>
#include <openssl/bn.h>

/* Custom primitive type for long handling. This converts between an ASN1_INTEGER
 * and a long directly.
 */


static int long_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
static void long_free(ASN1_VALUE **pval, const ASN1_ITEM *it);

static int long_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype, const ASN1_ITEM *it);
static int long_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len, int utype, char *free_cont, const ASN1_ITEM *it);

static ASN1_PRIMITIVE_FUNCS long_pf = {
	NULL, 0,
	long_new,
	long_free,
	long_free,	/* Clear should set to initial value */
	long_c2i,
	long_i2c
};

ASN1_ITEM_start(LONG)
	ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &long_pf, ASN1_LONG_UNDEF, "LONG"
ASN1_ITEM_end(LONG)

ASN1_ITEM_start(ZLONG)
	ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &long_pf, 0, "ZLONG"
ASN1_ITEM_end(ZLONG)

static int long_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
	*(long *)pval = it->size;
	return 1;
}

static void long_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
	*(long *)pval = it->size;
}

static int long_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype, const ASN1_ITEM *it)
{
	long ltmp;
	unsigned long utmp;
	int clen, pad, i;
	/* this exists to bypass broken gcc optimization */
	char *cp = (char *)pval;

	/* use memcpy, because we may not be long aligned */
	memcpy(&ltmp, cp, sizeof(long));

	if(ltmp == it->size) return -1;
	/* Convert the long to positive: we subtract one if negative so
	 * we can cleanly handle the padding if only the MSB of the leading
	 * octet is set. 
	 */
	if(ltmp < 0) utmp = -ltmp - 1;
	else utmp = ltmp;
	clen = BN_num_bits_word(utmp);
	/* If MSB of leading octet set we need to pad */
	if(!(clen & 0x7)) pad = 1;
	else pad = 0;

	/* Convert number of bits to number of octets */
	clen = (clen + 7) >> 3;

	if(cont) {
		if(pad) *cont++ = (ltmp < 0) ? 0xff : 0;
		for(i = clen - 1; i >= 0; i--) {
			cont[i] = (unsigned char)(utmp & 0xff);
			if(ltmp < 0) cont[i] ^= 0xff;
			utmp >>= 8;
		}
	}
	return clen + pad;
}

static int long_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
		    int utype, char *free_cont, const ASN1_ITEM *it)
{
	int neg, i;
	long ltmp;
	unsigned long utmp = 0;
	char *cp = (char *)pval;
	if(len > (int)sizeof(long)) {
		ASN1err(ASN1_F_LONG_C2I, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG);
		return 0;
	}
	/* Is it negative? */
	if(len && (cont[0] & 0x80)) neg = 1;
	else neg = 0;
	utmp = 0;
	for(i = 0; i < len; i++) {
		utmp <<= 8;
		if(neg) utmp |= cont[i] ^ 0xff;
		else utmp |= cont[i];
	}
	ltmp = (long)utmp;
	if(neg) {
		ltmp++;
		ltmp = -ltmp;
	}
	if(ltmp == it->size) {
		ASN1err(ASN1_F_LONG_C2I, ASN1_R_INTEGER_TOO_LARGE_FOR_LONG);
		return 0;
	}
	memcpy(cp, &ltmp, sizeof(long));
	return 1;
}