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Diffstat (limited to 'src/tpm2/BnConvert.c')
| -rw-r--r-- | src/tpm2/BnConvert.c | 299 |
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diff --git a/src/tpm2/BnConvert.c b/src/tpm2/BnConvert.c new file mode 100644 index 0000000..49cd6d5 --- /dev/null +++ b/src/tpm2/BnConvert.c @@ -0,0 +1,299 @@ +/********************************************************************************/ +/* */ +/* conversion functions that will convert TPM2B to/from internal format */ +/* Written by Ken Goldman */ +/* IBM Thomas J. Watson Research Center */ +/* $Id: BnConvert.c 1519 2019-11-15 20:43:51Z kgoldman $ */ +/* */ +/* Licenses and Notices */ +/* */ +/* 1. Copyright Licenses: */ +/* */ +/* - Trusted Computing Group (TCG) grants to the user of the source code in */ +/* this specification (the "Source Code") a worldwide, irrevocable, */ +/* nonexclusive, royalty free, copyright license to reproduce, create */ +/* derivative works, distribute, display and perform the Source Code and */ +/* derivative works thereof, and to grant others the rights granted herein. */ +/* */ +/* - The TCG grants to the user of the other parts of the specification */ +/* (other than the Source Code) the rights to reproduce, distribute, */ +/* display, and perform the specification solely for the purpose of */ +/* developing products based on such documents. */ +/* */ +/* 2. Source Code Distribution Conditions: */ +/* */ +/* - Redistributions of Source Code must retain the above copyright licenses, */ +/* this list of conditions and the following disclaimers. */ +/* */ +/* - Redistributions in binary form must reproduce the above copyright */ +/* licenses, this list of conditions and the following disclaimers in the */ +/* documentation and/or other materials provided with the distribution. */ +/* */ +/* 3. Disclaimers: */ +/* */ +/* - THE COPYRIGHT LICENSES SET FORTH ABOVE DO NOT REPRESENT ANY FORM OF */ +/* LICENSE OR WAIVER, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, WITH */ +/* RESPECT TO PATENT RIGHTS HELD BY TCG MEMBERS (OR OTHER THIRD PARTIES) */ +/* THAT MAY BE NECESSARY TO IMPLEMENT THIS SPECIFICATION OR OTHERWISE. */ +/* Contact TCG Administration (admin@trustedcomputinggroup.org) for */ +/* information on specification licensing rights available through TCG */ +/* membership agreements. */ +/* */ +/* - THIS SPECIFICATION IS PROVIDED "AS IS" WITH NO EXPRESS OR IMPLIED */ +/* WARRANTIES WHATSOEVER, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR */ +/* FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, COMPLETENESS, OR */ +/* NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS, OR ANY WARRANTY */ +/* OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. */ +/* */ +/* - Without limitation, TCG and its members and licensors disclaim all */ +/* liability, including liability for infringement of any proprietary */ +/* rights, relating to use of information in this specification and to the */ +/* implementation of this specification, and TCG disclaims all liability for */ +/* cost of procurement of substitute goods or services, lost profits, loss */ +/* of use, loss of data or any incidental, consequential, direct, indirect, */ +/* or special damages, whether under contract, tort, warranty or otherwise, */ +/* arising in any way out of use or reliance upon this specification or any */ +/* information herein. */ +/* */ +/* (c) Copyright IBM Corp. and others, 2016 - 2019 */ +/* */ +/********************************************************************************/ + +/* 10.2.2 BnConvert.c */ +/* 10.2.2.1 Introduction */ +/* This file contains the basic conversion functions that will convert TPM2B to/from the internal + format. The internal format is a bigNum, */ +/* 10.2.2.2 Includes */ +#include "Tpm.h" +/* 10.2.2.3 Functions */ +/* 10.2.2.3.1 BnFromBytes() */ +/* This function will convert a big-endian byte array to the internal number format. If bn is NULL, + then the output is NULL. If bytes is null or the required size is 0, then the output is set to + zero */ +LIB_EXPORT bigNum +BnFromBytes( + bigNum bn, + const BYTE *bytes, + NUMBYTES nBytes + ) +{ + const BYTE *pFrom; // 'p' points to the least significant bytes of source + BYTE *pTo; // points to least significant bytes of destination + crypt_uword_t size; + // + size = (bytes != NULL) ? BYTES_TO_CRYPT_WORDS(nBytes) : 0; + // If nothing in, nothing out + if(bn == NULL) + return NULL; + // make sure things fit + pAssert(BnGetAllocated(bn) >= size); + if(size > 0) + { + // Clear the topmost word in case it is not filled with data + bn->d[size - 1] = 0; + // Moving the input bytes from the end of the list (LSB) end + pFrom = bytes + nBytes - 1; + // To the LS0 of the LSW of the bigNum. + pTo = (BYTE *)bn->d; + for(; nBytes != 0; nBytes--) + *pTo++ = *pFrom--; + // For a little-endian machine, the conversion is a straight byte + // reversal. For a big-endian machine, we have to put the words in + // big-endian byte order +#if BIG_ENDIAN_TPM + { + crypt_word_t t; + for(t = (crypt_word_t)size - 1; t >= 0; t--) + bn->d[t] = SWAP_CRYPT_WORD(bn->d[t]); + } +#endif + } + BnSetTop(bn, size); + return bn; +} +/* 10.2.2.3.2 BnFrom2B() */ +/* Convert an TPM2B to a BIG_NUM. If the input value does not exist, or the output does not exist, + or the input will not fit into the output the function returns NULL */ +LIB_EXPORT bigNum +BnFrom2B( + bigNum bn, // OUT: + const TPM2B *a2B // IN: number to convert + ) +{ + if(a2B != NULL) + return BnFromBytes(bn, a2B->buffer, a2B->size); + // Make sure that the number has an initialized value rather than whatever + // was there before + BnSetTop(bn, 0); // Function accepts NULL + return NULL; +} +/* 10.2.2.3.3 BnFromHex() */ +/* Convert a hex string into a bigNum. This is primarily used in debugging. */ +#ifdef _SM2_SIGN_DEBUG // libtpms added +LIB_EXPORT bigNum +BnFromHex( + bigNum bn, // OUT: + const char *hex // IN: + ) +{ +#define FromHex(a) ((a) - (((a) > 'a') ? ('a' + 10) \ + : ((a) > 'A') ? ('A' - 10) : '0')) + unsigned i; + unsigned wordCount; + const char *p; + BYTE *d = (BYTE *)&(bn->d[0]); + // + pAssert(bn && hex); + i = (unsigned)strlen(hex); + wordCount = BYTES_TO_CRYPT_WORDS((i + 1) / 2); + if((i == 0) || (wordCount >= BnGetAllocated(bn))) + BnSetWord(bn, 0); + else + { + bn->d[wordCount - 1] = 0; + p = hex + i - 1; + for(;i > 1; i -= 2) + { + BYTE a; + a = FromHex(*p); + p--; + *d++ = a + (FromHex(*p) << 4); + p--; + } + if(i == 1) + *d = FromHex(*p); + } +#if !BIG_ENDIAN_TPM + for(i = 0; i < wordCount; i++) + bn->d[i] = SWAP_CRYPT_WORD(bn->d[i]); +#endif // BIG_ENDIAN_TPM + BnSetTop(bn, wordCount); + return bn; +} +#endif // libtpms added +/* 10.2.2.3.4 BnToBytes() */ +/* This function converts a BIG_NUM to a byte array. It converts the bigNum to a big-endian byte + string and sets size to the normalized value. If size is an input 0, then the receiving buffer is + guaranteed to be large enough for the result and the size will be set to the size required for + bigNum (leading zeros suppressed). */ +/* The conversion for a little-endian machine simply requires that all significant bytes of the + bigNum be reversed. For a big-endian machine, rather than unpack each word individually, + the bigNum is converted to little-endian words, copied, and then converted back to big-endian. */ +LIB_EXPORT BOOL +BnToBytes( + bigConst bn, + BYTE *buffer, + NUMBYTES *size // This the number of bytes that are + // available in the buffer. The result + // should be this big. + ) +{ + crypt_uword_t requiredSize; + BYTE *pFrom; + BYTE *pTo; + crypt_uword_t count; + // + // validate inputs + pAssert(bn && buffer && size); + requiredSize = (BnSizeInBits(bn) + 7) / 8; + if(requiredSize == 0) + { + // If the input value is 0, return a byte of zero + *size = 1; + *buffer = 0; + } + else + { +#if BIG_ENDIAN_TPM + // Copy the constant input value into a modifiable value + BN_VAR(bnL, LARGEST_NUMBER_BITS * 2); + BnCopy(bnL, bn); + // byte swap the words in the local value to make them little-endian + for(count = 0; count < bnL->size; count++) + bnL->d[count] = SWAP_CRYPT_WORD(bnL->d[count]); + bn = (bigConst)bnL; +#endif + if(*size == 0) + *size = (NUMBYTES)requiredSize; + pAssert(requiredSize <= *size); + // Byte swap the number (not words but the whole value) + count = *size; + // Start from the least significant word and offset to the most significant + // byte which is in some high word + pFrom = (BYTE *)(&bn->d[0]) + requiredSize - 1; + pTo = buffer; + // If the number of output bytes is larger than the number bytes required + // for the input number, pad with zeros + for(count = *size; count > requiredSize; count--) + *pTo++ = 0; + // Move the most significant byte at the end of the BigNum to the next most + // significant byte position of the 2B and repeat for all significant bytes. + for(; requiredSize > 0; requiredSize--) + *pTo++ = *pFrom--; + } + return TRUE; +} +/* 10.2.2.3.5 BnTo2B() */ +/* Function to convert a BIG_NUM to TPM2B. The TPM2B size is set to the requested size which may + require padding. If size is non-zero and less than required by the value in bn then an error is + returned. If size is zero, then the TPM2B is assumed to be large enough for the data and + a2b->size will be adjusted accordingly. */ +LIB_EXPORT BOOL +BnTo2B( + bigConst bn, // IN: + TPM2B *a2B, // OUT: + NUMBYTES size // IN: the desired size + ) +{ + // Set the output size + if(bn && a2B) + { + a2B->size = size; + return BnToBytes(bn, a2B->buffer, &a2B->size); + } + return FALSE; +} +#if ALG_ECC +/* 10.2.2.3.6 BnPointFrom2B() */ +/* Function to create a BIG_POINT structure from a 2B point. A point is going to be two ECC values + in the same buffer. The values are going to be the size of the modulus. They are in modular + form. */ +LIB_EXPORT bn_point_t * +BnPointFrom2B( + bigPoint ecP, // OUT: the preallocated point structure + TPMS_ECC_POINT *p // IN: the number to convert + ) +{ + if(p == NULL) + return NULL; + if(NULL != ecP) + { + BnFrom2B(ecP->x, &p->x.b); + BnFrom2B(ecP->y, &p->y.b); + BnSetWord(ecP->z, 1); + } + return ecP; +} +/* 10.2.2.3.7 BnPointTo2B() */ +/* This function converts a BIG_POINT into a TPMS_ECC_POINT. A TPMS_ECC_POINT contains two + TPM2B_ECC_PARAMETER values. The maximum size of the parameters is dependent on the maximum EC key + size used in an implementation. The presumption is that the TPMS_ECC_POINT is large enough to + hold 2 TPM2B values, each as large as a MAX_ECC_PARAMETER_BYTES */ +LIB_EXPORT BOOL +BnPointTo2B( + TPMS_ECC_POINT *p, // OUT: the converted 2B structure + bigPoint ecP, // IN: the values to be converted + bigCurve E // IN: curve descriptor for the point + ) +{ + UINT16 size; + // + pAssert(p && ecP && E); + pAssert(BnEqualWord(ecP->z, 1)); + // BnMsb is the bit number of the MSB. This is one less than the number of bits + size = (UINT16)BITS_TO_BYTES(BnSizeInBits(CurveGetOrder(AccessCurveData(E)))); + BnTo2B(ecP->x, &p->x.b, size); + BnTo2B(ecP->y, &p->y.b, size); + return TRUE; +} +#endif // TPM_ALG_ECC |