aescmac.c File Reference

#include "precomp.h"

Include dependency graph for aescmac.c:

Go to the source code of this file.

Functions
VOID SYMCRYPT_CALL	SymCryptCmacMunge (_Inout_updates_bytes_(SYMCRYPT_AES_BLOCK_SIZE) BYTE buf[SYMCRYPT_AES_BLOCK_SIZE])
SYMCRYPT_ERROR SYMCRYPT_CALL	SymCryptAesCmacExpandKey (_Out_ PSYMCRYPT_AES_CMAC_EXPANDED_KEY pExpandedKey, _In_reads_(cbKey) PCBYTE pbKey, SIZE_T cbKey)
VOID SYMCRYPT_CALL	SymCryptAesCmacKeyCopy (_In_ PCSYMCRYPT_AES_CMAC_EXPANDED_KEY pSrc, _Out_ PSYMCRYPT_AES_CMAC_EXPANDED_KEY pDst)
VOID SYMCRYPT_CALL	SymCryptAesCmac (_In_ PSYMCRYPT_AES_CMAC_EXPANDED_KEY pExpandedKey, _In_reads_(cbData) PCBYTE pbData, SIZE_T cbData, _Out_writes_(SYMCRYPT_AES_CMAC_RESULT_SIZE) PBYTE pbResult)
VOID SYMCRYPT_CALL	SymCryptAesCmacStateCopy (_In_ PCSYMCRYPT_AES_CMAC_STATE pSrc, _In_opt_ PCSYMCRYPT_AES_CMAC_EXPANDED_KEY pExpandedKey, _Out_ PSYMCRYPT_AES_CMAC_STATE pDst)
VOID SYMCRYPT_CALL	SymCryptAesCmacInit (_Out_ PSYMCRYPT_AES_CMAC_STATE pState, _In_ PCSYMCRYPT_AES_CMAC_EXPANDED_KEY pExpandedKey)
VOID SYMCRYPT_CALL	SymCryptAesCmacAppend (_Inout_ PSYMCRYPT_AES_CMAC_STATE pState, _In_reads_(cbData) PCBYTE pbData, SIZE_T cbData)
VOID SYMCRYPT_CALL	SymCryptAesCmacResult (_Inout_ PSYMCRYPT_AES_CMAC_STATE pState, _Out_writes_(SYMCRYPT_AES_CMAC_RESULT_SIZE) PBYTE pbResult)
VOID SYMCRYPT_CALL	SymCryptAesCmacSelftest (void)

Variables
const SYMCRYPT_MAC	SymCryptAesCmacAlgorithm_fast
const PCSYMCRYPT_MAC	SymCryptAesCmacAlgorithm = &SymCryptAesCmacAlgorithm_fast
static const BYTE	aesCmacKat [SYMCRYPT_AES_CMAC_RESULT_SIZE]

Function Documentation

SymCryptAesCmac()

VOID SYMCRYPT_CALL SymCryptAesCmac	(	_In_ PSYMCRYPT_AES_CMAC_EXPANDED_KEY	pExpandedKey,
		_In_reads_(cbData) PCBYTE	pbData,
		SIZE_T	cbData,
		_Out_writes_(SYMCRYPT_AES_CMAC_RESULT_SIZE) PBYTE	pbResult
	)

Definition at line 93 of file aescmac.c.

{
    SYMCRYPT_AES_CMAC_STATE state;
 
    SymCryptAesCmacInit( &state, pExpandedKey );
    SymCryptAesCmacAppend( &state, pbData, cbData );
    SymCryptAesCmacResult( &state, pbResult );
 
    SymCryptWipeKnownSize( &state, sizeof( state ) );
}

Referenced by SymCryptAesCmacSelftest().

SymCryptAesCmacAppend()

VOID SYMCRYPT_CALL SymCryptAesCmacAppend	(	_Inout_ PSYMCRYPT_AES_CMAC_STATE	pState,
		_In_reads_(cbData) PCBYTE	pbData,
		SIZE_T	cbData
	)

Definition at line 150 of file aescmac.c.

{
 
    SYMCRYPT_CHECK_MAGIC( pState );
 
    if( pState->bytesInBuf != 0 )
    {
        SIZE_T freeInBuf = SYMCRYPT_AES_BLOCK_SIZE - pState->bytesInBuf;
        SYMCRYPT_ASSERT( freeInBuf < SYMCRYPT_AES_BLOCK_SIZE );
 
        if( cbData <= freeInBuf )
        {
            // Do nothing.
            // the data will be copied into the buf at the end of this function
            //
        }
        else
        {
            memcpy( &pState->buf[pState->bytesInBuf], pbData, freeInBuf );
            pbData += freeInBuf;
            cbData -= freeInBuf;
            SymCryptAesCbcMac( &pState->pKey->aesKey, &pState->chain[0], &pState->buf[0], SYMCRYPT_AES_BLOCK_SIZE );
            pState->bytesInBuf = 0;
        }
    }
 
    //
    // At this point, either pState->bytesInBuf == 0, or it is !=0 but cbData is small enough that all the
    // data will still fit in the buffer without further processing.
    //
 
    if( cbData > SYMCRYPT_AES_BLOCK_SIZE )
    {
        SIZE_T bytesToDo = (cbData-1) & ~(SIZE_T)(SYMCRYPT_AES_BLOCK_SIZE - 1);
        SymCryptAesCbcMac( &pState->pKey->aesKey, &pState->chain[0], pbData, bytesToDo );
        pbData += bytesToDo;
        cbData -= bytesToDo;
    }
 
    if( cbData > 0 )
    {
        memcpy( &pState->buf[pState->bytesInBuf], pbData, cbData );
        pState->bytesInBuf += cbData;
    }
}

Referenced by SymCryptAesCmac().

SymCryptAesCmacExpandKey()

SYMCRYPT_ERROR SYMCRYPT_CALL SymCryptAesCmacExpandKey	(	_Out_ PSYMCRYPT_AES_CMAC_EXPANDED_KEY	pExpandedKey,
		_In_reads_(cbKey) PCBYTE	pbKey,
		SIZE_T	cbKey
	)

Definition at line 44 of file aescmac.c.

{
    SYMCRYPT_ERROR    scError = SYMCRYPT_NO_ERROR;
    SYMCRYPT_ALIGN  BYTE            buf[SYMCRYPT_AES_BLOCK_SIZE];
 
    scError = SymCryptAesExpandKey( &pExpandedKey->aesKey, pbKey, cbKey );
    if( scError != SYMCRYPT_NO_ERROR )
    {
        goto cleanup;
    }
 
    SymCryptWipeKnownSize( buf, sizeof( buf ) );
 
    SymCryptAesEncrypt( &pExpandedKey->aesKey, buf, buf );
 
    SymCryptCmacMunge( buf );
    memcpy( &pExpandedKey->K1, buf, sizeof( buf ) );
    SymCryptCmacMunge( buf );
    memcpy( &pExpandedKey->K2, buf, sizeof( buf ) );
 
    SymCryptWipeKnownSize( buf, sizeof( buf ) );
 
    SYMCRYPT_SET_MAGIC( pExpandedKey );
 
cleanup:
 
    return scError;
}

Referenced by SymCryptAesCmacSelftest().

SymCryptAesCmacInit()

VOID SYMCRYPT_CALL SymCryptAesCmacInit	(	_Out_ PSYMCRYPT_AES_CMAC_STATE	pState,
		_In_ PCSYMCRYPT_AES_CMAC_EXPANDED_KEY	pExpandedKey
	)

Definition at line 135 of file aescmac.c.

{
    SYMCRYPT_CHECK_MAGIC( pExpandedKey );
 
    pState->bytesInBuf = 0;
    SymCryptWipeKnownSize( pState->chain, sizeof( pState->chain ) );
    pState->pKey = pExpandedKey;
 
    SYMCRYPT_SET_MAGIC( pState );
}

Referenced by SymCryptAesCmac().

SymCryptAesCmacKeyCopy()

VOID SYMCRYPT_CALL SymCryptAesCmacKeyCopy	(	_In_ PCSYMCRYPT_AES_CMAC_EXPANDED_KEY	pSrc,
		_Out_ PSYMCRYPT_AES_CMAC_EXPANDED_KEY	pDst
	)

Definition at line 79 of file aescmac.c.

{
    SYMCRYPT_CHECK_MAGIC( pSrc );
    SymCryptAesKeyCopy( &pSrc->aesKey, &pDst->aesKey );
    memcpy( pDst->K1, pSrc->K1, sizeof( pDst->K1 ) );
    memcpy( pDst->K2, pSrc->K2, sizeof( pDst->K2 ) );
    SYMCRYPT_SET_MAGIC( pDst );
}

SymCryptAesCmacResult()

VOID SYMCRYPT_CALL SymCryptAesCmacResult	(	_Inout_ PSYMCRYPT_AES_CMAC_STATE	pState,
		_Out_writes_(SYMCRYPT_AES_CMAC_RESULT_SIZE) PBYTE	pbResult
	)

Definition at line 202 of file aescmac.c.

{
    SYMCRYPT_CHECK_MAGIC( pState );
 
    if( pState->bytesInBuf < SYMCRYPT_AES_BLOCK_SIZE )
    {
        SymCryptWipe( &pState->buf[pState->bytesInBuf + 1], SYMCRYPT_AES_BLOCK_SIZE - pState->bytesInBuf - 1 );
        pState->buf[pState->bytesInBuf] = 0x80;
        SymCryptXorBytes( &pState->buf[0], &pState->pKey->K2[0], &pState->buf[0], SYMCRYPT_AES_BLOCK_SIZE );
    }
    else
    {
        SymCryptXorBytes( &pState->buf[0], &pState->pKey->K1[0], &pState->buf[0], SYMCRYPT_AES_BLOCK_SIZE );
    }
 
    SymCryptAesCbcMac( &pState->pKey->aesKey, &pState->chain[0], &pState->buf[0], SYMCRYPT_AES_BLOCK_SIZE );
    memcpy( pbResult, &pState->chain[0], SYMCRYPT_AES_BLOCK_SIZE );
 
    //
    // Put the state back in the original starting state,
    // and wipe any traces of the data.
    //
    pState->bytesInBuf = 0;
    SymCryptWipeKnownSize( pState->chain, sizeof( pState->chain ) );
    SymCryptWipeKnownSize( pState->buf, sizeof( pState->buf ) );
}

Referenced by SymCryptAesCmac().

SymCryptAesCmacSelftest()

VOID SYMCRYPT_CALL SymCryptAesCmacSelftest

(

void

)

Definition at line 240 of file aescmac.c.

{
    SYMCRYPT_AES_CMAC_EXPANDED_KEY xKey;
    BYTE res[SYMCRYPT_AES_CMAC_RESULT_SIZE];
 
    SymCryptAesCmacExpandKey( &xKey, SymCryptTestKey32, 16 );
    SymCryptAesCmac( &xKey, SymCryptTestMsg3, sizeof( SymCryptTestMsg3 ), res );
 
    SymCryptInjectError( res, sizeof( res ) );
    if( memcmp( res, aesCmacKat, sizeof( res ) ) != 0 )
    {
        SymCryptFatal( 'hsh5' );
    }
 
    //
    // Normally we would wipe the expanded key structure here,
    // but as this is a selftest with known data this is not needed.
    //
}

SymCryptAesCmacStateCopy()

VOID SYMCRYPT_CALL SymCryptAesCmacStateCopy	(	_In_ PCSYMCRYPT_AES_CMAC_STATE	pSrc,
		_In_opt_ PCSYMCRYPT_AES_CMAC_EXPANDED_KEY	pExpandedKey,
		_Out_ PSYMCRYPT_AES_CMAC_STATE	pDst
	)

Definition at line 111 of file aescmac.c.

{
    SYMCRYPT_CHECK_MAGIC( pSrc );
    *pDst = *pSrc;
 
    if( pExpandedKey == NULL )
    {
        SYMCRYPT_CHECK_MAGIC( pSrc->pKey );
        pDst->pKey = pSrc->pKey;
    }
    else
    {
        SYMCRYPT_CHECK_MAGIC( pExpandedKey );
        pDst->pKey = pExpandedKey;
    }
 
    SYMCRYPT_SET_MAGIC( pDst );
}

SymCryptCmacMunge()

VOID SYMCRYPT_CALL SymCryptCmacMunge

(

_Inout_updates_bytes_(SYMCRYPT_AES_BLOCK_SIZE) BYTE

buf[SYMCRYPT_AES_BLOCK_SIZE]

)

Definition at line 25 of file aescmac.c.

{
    SIZE_T carry = 0;
    SIZE_T tmp;
    int i;
 
    for( i=15; i>=0; i-- )
    {
        tmp = buf[i];
        buf[i] = ((tmp << 1) | carry) & 0xff;
        carry = tmp >> 7;
    }
 
    buf[15] ^= (0 - carry) & 0x87;                // This is the R_128 value from SP 800-38B 5.3
}

Referenced by SymCryptAesCmacExpandKey().

Variable Documentation

aesCmacKat

const BYTE aesCmacKat[SYMCRYPT_AES_CMAC_RESULT_SIZE]

static

Initial value:

= {
    0x0a, 0x54, 0xa6, 0xa4, 0x25, 0xd4, 0x84, 0x38, 0xc3, 0xf8, 0xbb, 0xe0, 0x9b, 0xf9, 0x44, 0xcc,
}

Definition at line 233 of file aescmac.c.

Referenced by SymCryptAesCmacSelftest().

SymCryptAesCmacAlgorithm

const PCSYMCRYPT_MAC SymCryptAesCmacAlgorithm = &SymCryptAesCmacAlgorithm_fast

Definition at line 21 of file aescmac.c.

SymCryptAesCmacAlgorithm_fast

const SYMCRYPT_MAC SymCryptAesCmacAlgorithm_fast

Initial value:

= {
    SymCryptAesCmacExpandKey,
    SymCryptAesCmacInit,
    SymCryptAesCmacAppend,
    SymCryptAesCmacResult,
    sizeof(SYMCRYPT_AES_CMAC_EXPANDED_KEY),
    sizeof(SYMCRYPT_AES_CMAC_STATE),
    SYMCRYPT_AES_CMAC_RESULT_SIZE,
    NULL,
    0,
}

Definition at line 9 of file aescmac.c.