/* 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>

EXPORT_C ASN1_INTEGER *ASN1_INTEGER_dup(ASN1_INTEGER *x)

{ return M_ASN1_INTEGER_dup(x);}

EXPORT_C int ASN1_INTEGER_cmp(ASN1_INTEGER *x, 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.

 */

EXPORT_C 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 */

EXPORT_C 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).

 */

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

	     long length)

	{

	ASN1_INTEGER *ret=NULL;

	const unsigned char *p;

	unsigned char *to,*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;

		}

	to=s;

	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);

	}

EXPORT_C 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);

	}

EXPORT_C long ASN1_INTEGER_get(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(0xffffffffL);

		}

	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);

	}

EXPORT_C ASN1_INTEGER *BN_to_ASN1_INTEGER(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);

	}

EXPORT_C BIGNUM *ASN1_INTEGER_to_BN(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)