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// This file was extracted from the TCG Published
// Trusted Platform Module Library
// Part 4: Supporting Routines
// Family "2.0"
// Level 00 Revision 01.16
// October 30, 2014
#include "OsslCryptoEngine.h"
//
//
// Functions
//
// BnTo2B()
//
// This function is used to convert a BigNum() to a byte array of the specified size. If the number is too large
// to fit, then 0 is returned. Otherwise, the number is converted into the low-order bytes of the provided array
// and the upper bytes are set to zero.
//
// Return Value Meaning
//
// 0 failure (probably fatal)
// 1 conversion successful
//
BOOL
BnTo2B(
TPM2B *outVal, // OUT: place for the result
BIGNUM *inVal, // IN: number to convert
UINT16 size // IN: size of the output.
)
{
BYTE *pb = outVal->buffer;
outVal->size = size;
size = size - (((UINT16) BN_num_bits(inVal) + 7) / 8);
if(size < 0)
return FALSE;
for(;size > 0; size--)
*pb++ = 0;
BN_bn2bin(inVal, pb);
return TRUE;
}
//
//
// Copy2B()
//
// This function copies a TPM2B structure. The compiler can't generate a copy of a TPM2B generic
// structure because the actual size is not known. This function performs the copy on any TPM2B pair. The
// size of the destination should have been checked before this call to make sure that it will hold the TPM2B
// being copied.
// This replicates the functionality in the MemoryLib.c.
//
void
Copy2B(
TPM2B *out, // OUT: The TPM2B to receive the copy
TPM2B *in // IN: the TPM2B to copy
)
{
BYTE *pIn = in->buffer;
BYTE *pOut = out->buffer;
int count;
out->size = in->size;
for(count = in->size; count > 0; count--)
*pOut++ = *pIn++;
return;
}
//
//
// BnFrom2B()
//
// This function creates a BIGNUM from a TPM2B and fails if the conversion fails.
//
BIGNUM *
BnFrom2B(
BIGNUM *out, // OUT: The BIGNUM
const TPM2B *in // IN: the TPM2B to copy
)
{
if(BN_bin2bn(in->buffer, in->size, out) == NULL)
FAIL(FATAL_ERROR_INTERNAL);
return out;
}