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Windows: Use BCryptGenRandom instead of deprecated CryptGenRandom to generate secure random bytes

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This commit is contained in:
Mounir IDRASSI
2024-11-13 02:04:13 +01:00
parent a1ade61c59
commit ec4b44c238
1 changed files with 21 additions and 27 deletions
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48
src/Common/Random.c
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@@ -19,6 +19,7 @@
#include "Crypto\jitterentropy.h"
#include "Crypto\rdrand.h"
#include <Strsafe.h>
#include <bcrypt.h>
static unsigned __int8 buffer[RNG_POOL_SIZE];
static unsigned char *pRandPool = NULL;
@@ -89,16 +90,17 @@ BOOL volatile bThreadTerminate = FALSE; /* This variable is shared among thread'
HANDLE hNetAPI32 = NULL;
// CryptoAPI
BOOL CryptoAPIAvailable = FALSE;
DWORD CryptoAPILastError = ERROR_SUCCESS;
HCRYPTPROV hCryptProv;
typedef DWORD (WINAPI *RtlNtStatusToDosError_t)(NTSTATUS);
RtlNtStatusToDosError_t pRtlNtStatusToDosError = NULL;
/* Init the random number generator, setup the hooks, and start the thread */
int RandinitWithCheck ( int* pAlreadyInitialized)
{
BOOL bIgnoreHookError = FALSE;
DWORD dwLastError = ERROR_SUCCESS;
HMODULE ntdll;
if (GetMaxPkcs5OutSize() > RNG_POOL_SIZE)
TC_THROW_FATAL_EXCEPTION;
@@ -143,14 +145,14 @@ int RandinitWithCheck ( int* pAlreadyInitialized)
goto error;
}
if (!CryptAcquireContext (&hCryptProv, NULL, MS_ENHANCED_PROV, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
{
CryptoAPIAvailable = FALSE;
CryptoAPILastError = GetLastError ();
ntdll = GetModuleHandleW(L"ntdll.dll");
if (!ntdll) {
// If ntdll.dll is not found, return a fallback error code
CryptoAPILastError = ERROR_MOD_NOT_FOUND;
goto error;
}
else
CryptoAPIAvailable = TRUE;
pRtlNtStatusToDosError = (RtlNtStatusToDosError_t)GetProcAddress(ntdll, "RtlNtStatusToDosError");
if (!(PeriodicFastPollThreadHandle = (HANDLE) _beginthreadex (NULL, 0, PeriodicFastPollThreadProc, NULL, 0, NULL)))
goto error;
@@ -199,12 +201,6 @@ void RandStop (BOOL freePool)
hNetAPI32 = NULL;
}
if (CryptoAPIAvailable)
{
CryptReleaseContext (hCryptProv, 0);
CryptoAPIAvailable = FALSE;
CryptoAPILastError = ERROR_SUCCESS;
}
hMouse = NULL;
hKeyboard = NULL;
@@ -675,6 +671,7 @@ BOOL SlowPoll (void)
DWORD dwSize, status;
LPWSTR lpszLanW, lpszLanS;
int nDrive;
NTSTATUS bStatus = 0;
/* Find out whether this is an NT server or workstation if necessary */
if (isWorkstation == -1)
@@ -783,18 +780,16 @@ BOOL SlowPoll (void)
CloseHandle (hDevice);
}
// CryptoAPI: We always have a valid CryptoAPI context when we arrive here but
// we keep the check for clarity purpose
if ( !CryptoAPIAvailable )
return FALSE;
if (CryptGenRandom (hCryptProv, sizeof (buffer), buffer))
bStatus = BCryptGenRandom(NULL, buffer, sizeof(buffer), BCRYPT_USE_SYSTEM_PREFERRED_RNG);
if (NT_SUCCESS(bStatus))
{
RandaddBuf (buffer, sizeof (buffer));
}
else
{
/* return error in case CryptGenRandom fails */
CryptoAPILastError = GetLastError ();
/* return error in case BCryptGenRandom fails */
CryptoAPILastError = pRtlNtStatusToDosError (bStatus);
return FALSE;
}
@@ -838,6 +833,7 @@ BOOL FastPoll (void)
MEMORYSTATUSEX memoryStatus;
HANDLE handle;
POINT point;
NTSTATUS bStatus = 0;
/* Get various basic pieces of system information */
RandaddIntPtr (GetActiveWindow ()); /* Handle of active window */
@@ -928,18 +924,16 @@ BOOL FastPoll (void)
RandaddBuf ((unsigned char *) &dwTicks, sizeof (dwTicks));
}
// CryptoAPI: We always have a valid CryptoAPI context when we arrive here but
// we keep the check for clarity purpose
if ( !CryptoAPIAvailable )
return FALSE;
if (CryptGenRandom (hCryptProv, sizeof (buffer), buffer))
bStatus = BCryptGenRandom(NULL, buffer, sizeof(buffer), BCRYPT_USE_SYSTEM_PREFERRED_RNG);
if (NT_SUCCESS(bStatus))
{
RandaddBuf (buffer, sizeof (buffer));
}
else
{
/* return error in case CryptGenRandom fails */
CryptoAPILastError = GetLastError ();
/* return error in case BCryptGenRandom fails */
CryptoAPILastError = pRtlNtStatusToDosError (bStatus);
return FALSE;
}