87 lines
1.9 KiB
C
87 lines
1.9 KiB
C
/*
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* Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <stdio.h>
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#include "internal/cryptlib.h"
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#include "bn_local.h"
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int BN_bn2mpi(const BIGNUM *a, unsigned char *d)
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{
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int bits;
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int num = 0;
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int ext = 0;
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long l;
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bits = BN_num_bits(a);
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num = (bits + 7) / 8;
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if (bits > 0) {
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ext = ((bits & 0x07) == 0);
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}
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if (d == NULL)
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return (num + 4 + ext);
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l = num + ext;
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d[0] = (unsigned char)(l >> 24) & 0xff;
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d[1] = (unsigned char)(l >> 16) & 0xff;
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d[2] = (unsigned char)(l >> 8) & 0xff;
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d[3] = (unsigned char)(l) & 0xff;
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if (ext)
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d[4] = 0;
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num = BN_bn2bin(a, &(d[4 + ext]));
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if (a->neg)
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d[4] |= 0x80;
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return (num + 4 + ext);
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}
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BIGNUM *BN_mpi2bn(const unsigned char *d, int n, BIGNUM *ain)
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{
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long len;
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int neg = 0;
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BIGNUM *a = NULL;
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if (n < 4 || (d[0] & 0x80) != 0) {
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BNerr(BN_F_BN_MPI2BN, BN_R_INVALID_LENGTH);
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return NULL;
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}
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len = ((long)d[0] << 24) | ((long)d[1] << 16) | ((int)d[2] << 8) | (int)
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d[3];
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if ((len + 4) != n) {
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BNerr(BN_F_BN_MPI2BN, BN_R_ENCODING_ERROR);
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return NULL;
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}
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if (ain == NULL)
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a = BN_new();
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else
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a = ain;
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if (a == NULL)
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return NULL;
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if (len == 0) {
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a->neg = 0;
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a->top = 0;
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return a;
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}
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d += 4;
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if ((*d) & 0x80)
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neg = 1;
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if (BN_bin2bn(d, (int)len, a) == NULL) {
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if (ain == NULL)
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BN_free(a);
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return NULL;
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}
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a->neg = neg;
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if (neg) {
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BN_clear_bit(a, BN_num_bits(a) - 1);
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}
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bn_check_top(a);
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return a;
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}
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