audk/SecurityPkg/RandomNumberGenerator/RngDxe/RdRand.c

396 lines
9.6 KiB
C

/** @file
Support routines for RDRAND instruction access.
Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "RdRand.h"
#include "AesCore.h"
//
// Bit mask used to determine if RdRand instruction is supported.
//
#define RDRAND_MASK 0x40000000
/**
Determines whether or not RDRAND instruction is supported by the host hardware.
@retval EFI_SUCCESS RDRAND instruction supported.
@retval EFI_UNSUPPORTED RDRAND instruction not supported.
**/
EFI_STATUS
EFIAPI
IsRdRandSupported (
VOID
)
{
EFI_STATUS Status;
UINT32 RegEax;
UINT32 RegEbx;
UINT32 RegEcx;
UINT32 RegEdx;
BOOLEAN IsIntelCpu;
Status = EFI_UNSUPPORTED;
IsIntelCpu = FALSE;
//
// Checks whether the current processor is an Intel product by CPUID.
//
AsmCpuid (0, &RegEax, &RegEbx, &RegEcx, &RegEdx);
if ((CompareMem ((CHAR8 *)(&RegEbx), "Genu", 4) == 0) &&
(CompareMem ((CHAR8 *)(&RegEdx), "ineI", 4) == 0) &&
(CompareMem ((CHAR8 *)(&RegEcx), "ntel", 4) == 0)) {
IsIntelCpu = TRUE;
}
if (IsIntelCpu) {
//
// Determine RDRAND support by examining bit 30 of the ECX register returned by CPUID.
// A value of 1 indicates that processor supports RDRAND instruction.
//
AsmCpuid (1, 0, 0, &RegEcx, 0);
if ((RegEcx & RDRAND_MASK) == RDRAND_MASK) {
Status = EFI_SUCCESS;
}
}
return Status;
}
/**
Calls RDRAND to obtain a 16-bit random number.
@param[out] Rand Buffer pointer to store the random result.
@param[in] NeedRetry Determine whether or not to loop retry.
@retval EFI_SUCCESS RDRAND call was successful.
@retval EFI_NOT_READY Failed attempts to call RDRAND.
**/
EFI_STATUS
EFIAPI
RdRand16 (
OUT UINT16 *Rand,
IN BOOLEAN NeedRetry
)
{
UINT32 Index;
UINT32 RetryCount;
if (NeedRetry) {
RetryCount = RETRY_LIMIT;
} else {
RetryCount = 1;
}
//
// Perform a single call to RDRAND, or enter a loop call until RDRAND succeeds.
//
for (Index = 0; Index < RetryCount; Index++) {
if (RdRand16Step (Rand)) {
return EFI_SUCCESS;
}
}
return EFI_NOT_READY;
}
/**
Calls RDRAND to obtain a 32-bit random number.
@param[out] Rand Buffer pointer to store the random result.
@param[in] NeedRetry Determine whether or not to loop retry.
@retval EFI_SUCCESS RDRAND call was successful.
@retval EFI_NOT_READY Failed attempts to call RDRAND.
**/
EFI_STATUS
EFIAPI
RdRand32 (
OUT UINT32 *Rand,
IN BOOLEAN NeedRetry
)
{
UINT32 Index;
UINT32 RetryCount;
if (NeedRetry) {
RetryCount = RETRY_LIMIT;
} else {
RetryCount = 1;
}
//
// Perform a single call to RDRAND, or enter a loop call until RDRAND succeeds.
//
for (Index = 0; Index < RetryCount; Index++) {
if (RdRand32Step (Rand)) {
return EFI_SUCCESS;
}
}
return EFI_NOT_READY;
}
/**
Calls RDRAND to obtain a 64-bit random number.
@param[out] Rand Buffer pointer to store the random result.
@param[in] NeedRetry Determine whether or not to loop retry.
@retval EFI_SUCCESS RDRAND call was successful.
@retval EFI_NOT_READY Failed attempts to call RDRAND.
**/
EFI_STATUS
EFIAPI
RdRand64 (
OUT UINT64 *Rand,
IN BOOLEAN NeedRetry
)
{
UINT32 Index;
UINT32 RetryCount;
if (NeedRetry) {
RetryCount = RETRY_LIMIT;
} else {
RetryCount = 1;
}
//
// Perform a single call to RDRAND, or enter a loop call until RDRAND succeeds.
//
for (Index = 0; Index < RetryCount; Index++) {
if (RdRand64Step (Rand)) {
return EFI_SUCCESS;
}
}
return EFI_NOT_READY;
}
/**
Calls RDRAND to fill a buffer of arbitrary size with random bytes.
@param[in] Length Size of the buffer, in bytes, to fill with.
@param[out] RandBuffer Pointer to the buffer to store the random result.
@retval EFI_SUCCESS Random bytes generation succeeded.
@retval EFI_NOT_READY Failed to request random bytes.
**/
EFI_STATUS
EFIAPI
RdRandGetBytes (
IN UINTN Length,
OUT UINT8 *RandBuffer
)
{
EFI_STATUS Status;
UINT8 *Start;
UINT8 *ResidualStart;
UINTN *BlockStart;
UINTN TempRand;
UINTN Count;
UINTN Residual;
UINTN StartLen;
UINTN BlockNum;
UINTN Index;
ResidualStart = NULL;
TempRand = 0;
//
// Compute the address of the first word aligned (32/64-bit) block in the
// destination buffer, depending on whether we are in 32- or 64-bit mode.
//
Start = RandBuffer;
if (((UINT32)(UINTN)Start % (UINT32)sizeof(UINTN)) == 0) {
BlockStart = (UINTN *)Start;
Count = Length;
StartLen = 0;
} else {
BlockStart = (UINTN *)(((UINTN)Start & ~(UINTN)(sizeof(UINTN) - 1)) + (UINTN)sizeof(UINTN));
Count = Length - (sizeof (UINTN) - (UINT32)((UINTN)Start % sizeof (UINTN)));
StartLen = (UINT32)((UINTN)BlockStart - (UINTN)Start);
}
//
// Compute the number of word blocks and the remaining number of bytes.
//
Residual = Count % sizeof (UINTN);
BlockNum = Count / sizeof (UINTN);
if (Residual != 0) {
ResidualStart = (UINT8 *) (BlockStart + BlockNum);
}
//
// Obtain a temporary random number for use in the residuals. Failout if retry fails.
//
if (StartLen > 0) {
Status = RdRandWord ((UINTN *) &TempRand, TRUE);
if (EFI_ERROR (Status)) {
return Status;
}
}
//
// Populate the starting mis-aligned block.
//
for (Index = 0; Index < StartLen; Index++) {
Start[Index] = (UINT8)(TempRand & 0xff);
TempRand = TempRand >> 8;
}
//
// Populate the central aligned block. Fail out if retry fails.
//
Status = RdRandGetWords (BlockNum, (UINTN *)(BlockStart));
if (EFI_ERROR (Status)) {
return Status;
}
//
// Populate the final mis-aligned block.
//
if (Residual > 0) {
Status = RdRandWord ((UINTN *)&TempRand, TRUE);
if (EFI_ERROR (Status)) {
return Status;
}
for (Index = 0; Index < Residual; Index++) {
ResidualStart[Index] = (UINT8)(TempRand & 0xff);
TempRand = TempRand >> 8;
}
}
return EFI_SUCCESS;
}
/**
Creates a 128bit random value that is fully forward and backward prediction resistant,
suitable for seeding a NIST SP800-90 Compliant, FIPS 1402-2 certifiable SW DRBG.
This function takes multiple random numbers through RDRAND without intervening
delays to ensure reseeding and performs AES-CBC-MAC over the data to compute the
seed value.
@param[out] SeedBuffer Pointer to a 128bit buffer to store the random seed.
@retval EFI_SUCCESS Random seed generation succeeded.
@retval EFI_NOT_READY Failed to request random bytes.
**/
EFI_STATUS
EFIAPI
RdRandGetSeed128 (
OUT UINT8 *SeedBuffer
)
{
EFI_STATUS Status;
UINT8 RandByte[16];
UINT8 Key[16];
UINT8 Ffv[16];
UINT8 Xored[16];
UINT32 Index;
UINT32 Index2;
//
// Chose an arbitary key and zero the feed_forward_value (FFV)
//
for (Index = 0; Index < 16; Index++) {
Key[Index] = (UINT8) Index;
Ffv[Index] = 0;
}
//
// Perform CBC_MAC over 32 * 128 bit values, with 10us gaps between 128 bit value
// The 10us gaps will ensure multiple reseeds within the HW RNG with a large design margin.
//
for (Index = 0; Index < 32; Index++) {
MicroSecondDelay (10);
Status = RdRandGetBytes (16, RandByte);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Perform XOR operations on two 128-bit value.
//
for (Index2 = 0; Index2 < 16; Index2++) {
Xored[Index2] = RandByte[Index2] ^ Ffv[Index2];
}
AesEncrypt (Key, Xored, Ffv);
}
for (Index = 0; Index < 16; Index++) {
SeedBuffer[Index] = Ffv[Index];
}
return EFI_SUCCESS;
}
/**
Generate high-quality entropy source through RDRAND.
@param[in] Length Size of the buffer, in bytes, to fill with.
@param[out] Entropy Pointer to the buffer to store the entropy data.
@retval EFI_SUCCESS Entropy generation succeeded.
@retval EFI_NOT_READY Failed to request random data.
**/
EFI_STATUS
EFIAPI
RdRandGenerateEntropy (
IN UINTN Length,
OUT UINT8 *Entropy
)
{
EFI_STATUS Status;
UINTN BlockCount;
UINT8 Seed[16];
UINT8 *Ptr;
Status = EFI_NOT_READY;
BlockCount = Length / 16;
Ptr = (UINT8 *)Entropy;
//
// Generate high-quality seed for DRBG Entropy
//
while (BlockCount > 0) {
Status = RdRandGetSeed128 (Seed);
if (EFI_ERROR (Status)) {
return Status;
}
CopyMem (Ptr, Seed, 16);
BlockCount--;
Ptr = Ptr + 16;
}
//
// Populate the remained data as request.
//
Status = RdRandGetSeed128 (Seed);
if (EFI_ERROR (Status)) {
return Status;
}
CopyMem (Ptr, Seed, (Length % 16));
return Status;
}