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/*
* Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/asn1t.h>
#include <openssl/bn.h>
/*
* Custom primitive type for BIGNUM handling. This reads in an ASN1_INTEGER
* as a BIGNUM directly. Currently it ignores the sign which isn't a problem
* since all BIGNUMs used are non negative and anything that looks negative
* is normally due to an encoding error.
*/
#define BN_SENSITIVE 1
static int bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
static int bn_secure_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
static void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it);
static int bn_i2c(const ASN1_VALUE **pval, unsigned char *cont, int *putype,
const ASN1_ITEM *it);
static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
int utype, char *free_cont, const ASN1_ITEM *it);
static int bn_secure_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
int utype, char *free_cont, const ASN1_ITEM *it);
static int bn_print(BIO *out, const ASN1_VALUE **pval, const ASN1_ITEM *it,
int indent, const ASN1_PCTX *pctx);
static ASN1_PRIMITIVE_FUNCS bignum_pf = {
NULL, 0,
bn_new,
bn_free,
0,
bn_c2i,
bn_i2c,
bn_print
};
static ASN1_PRIMITIVE_FUNCS cbignum_pf = {
NULL, 0,
bn_secure_new,
bn_free,
0,
bn_secure_c2i,
bn_i2c,
bn_print
};
ASN1_ITEM_start(BIGNUM)
ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &bignum_pf, 0, "BIGNUM"
ASN1_ITEM_end(BIGNUM)
ASN1_ITEM_start(CBIGNUM)
ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &cbignum_pf, BN_SENSITIVE, "CBIGNUM"
ASN1_ITEM_end(CBIGNUM)
static int bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
*pval = (ASN1_VALUE *)BN_new();
if (*pval != NULL)
return 1;
else
return 0;
}
static int bn_secure_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
*pval = (ASN1_VALUE *)BN_secure_new();
if (*pval != NULL)
return 1;
else
return 0;
}
static void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
if (*pval == NULL)
return;
if (it->size & BN_SENSITIVE)
BN_clear_free((BIGNUM *)*pval);
else
BN_free((BIGNUM *)*pval);
*pval = NULL;
}
static int bn_i2c(const ASN1_VALUE **pval, unsigned char *cont, int *putype,
const ASN1_ITEM *it)
{
BIGNUM *bn;
int pad;
if (*pval == NULL)
return -1;
bn = (BIGNUM *)*pval;
/* If MSB set in an octet we need a padding byte */
if (BN_num_bits(bn) & 0x7)
pad = 0;
else
pad = 1;
if (cont) {
if (pad)
*cont++ = 0;
BN_bn2bin(bn, cont);
}
return pad + BN_num_bytes(bn);
}
static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
int utype, char *free_cont, const ASN1_ITEM *it)
{
BIGNUM *bn;
if (*pval == NULL && !bn_new(pval, it))
return 0;
bn = (BIGNUM *)*pval;
if (!BN_bin2bn(cont, len, bn)) {
bn_free(pval, it);
return 0;
}
return 1;
}
static int bn_secure_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
int utype, char *free_cont, const ASN1_ITEM *it)
{
int ret;
BIGNUM *bn;
if (*pval == NULL && !bn_secure_new(pval, it))
return 0;
ret = bn_c2i(pval, cont, len, utype, free_cont, it);
if (!ret)
return 0;
/* Set constant-time flag for all secure BIGNUMS */
bn = (BIGNUM *)*pval;
BN_set_flags(bn, BN_FLG_CONSTTIME);
return ret;
}
static int bn_print(BIO *out, const ASN1_VALUE **pval, const ASN1_ITEM *it,
int indent, const ASN1_PCTX *pctx)
{
if (!BN_print(out, *(BIGNUM **)pval))
return 0;
if (BIO_puts(out, "\n") <= 0)
return 0;
return 1;
}
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