/* 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)