cheat-engine/DBKKernel/sigcheck.c
2020-09-02 16:51:55 +02:00

327 lines
9.8 KiB
C

/*
sigcheck is responsible for checking if the controlling process is Cheat Engine or another program signed by Dark Byte and not someone elses/modified one
This is only in case of a signed release build
*/
#include <ntifs.h>
#include <windef.h>
#include <bcrypt.h>
#include <Ntstrsafe.h>
#include <ntimage.h>
#include "sigcheck.h"
unsigned char publicKey[]={0x45, 0x43, 0x53, 0x35, 0x42, 0x00, 0x00, 0x00, 0x00, 0x3A, 0xBA, 0x72, 0xCF, 0xA7, 0x79, 0xFA, 0x92, 0x96, 0x15, 0x8E, 0x69, 0x35, 0x19, 0x09, 0x99, 0x3C, 0x97, 0xE8, 0x18, 0x0B, 0xC6, 0x2C, 0x8B, 0x24, 0x5A, 0xD8, 0x1C, 0x86, 0x83, 0x89, 0xE7, 0xA4, 0xA9, 0x47, 0x11, 0x7E, 0x07, 0x74, 0x69, 0x74, 0x33, 0x0B, 0x1A, 0xB8, 0x63, 0x11, 0x51, 0xEA, 0x00, 0xD6, 0x26, 0xE7, 0x7C, 0x6D, 0x77, 0xA5, 0x0E, 0x9F, 0x37, 0x87, 0x7B, 0x79, 0x2F, 0xEE, 0x00, 0x65, 0x7A, 0xBF, 0x44, 0x79, 0xD1, 0x7E, 0x47, 0xBC, 0xF9, 0x6F, 0x31, 0x81, 0x85, 0x70, 0x78, 0x5D, 0xED, 0xA5, 0xC6, 0x15, 0x0F, 0x2C, 0x0A, 0x27, 0x3B, 0x3E, 0x36, 0xEB, 0x53, 0x3E, 0x3E, 0x75, 0xC1, 0xA3, 0x0A, 0xC0, 0xC1, 0x53, 0x3A, 0x77, 0xFB, 0x84, 0x88, 0x35, 0xE8, 0x86, 0xF0, 0xA2, 0x52, 0x86, 0x5D, 0x12, 0x2D, 0x03, 0x88, 0x00, 0x36, 0x2B, 0x8D, 0x21, 0x13, 0x99, 0x7F, 0x62};
NTSYSAPI NTSTATUS NTAPI ZwQueryInformationProcess(IN HANDLE ProcessHandle, IN PROCESSINFOCLASS ProcessInformationClass, OUT PVOID ProcessInformation, IN ULONG ProcessInformationLength, OUT PULONG ReturnLength OPTIONAL);
NTSYSAPI NTSTATUS NTAPI ZwQueryInformationThread(IN HANDLE ThreadHandle, IN THREADINFOCLASS ThreadInformationClass, OUT PVOID ThreadInformation, IN ULONG ThreadInformationLength, OUT PULONG ReturnLength OPTIONAL);
NTSTATUS LoadFile(PUNICODE_STRING filename, PVOID *buffer, DWORD *size)
/*
Loads the specified file into paged memory
pre: filename must be valid
post:
buffer will get a pointer to the loaded file
Size will get the size of the file
Caller is responsible for calling ExFreePool on the buffer
*/
{
HANDLE hFile;
OBJECT_ATTRIBUTES oa;
FILE_STANDARD_INFORMATION fsi;
IO_STATUS_BLOCK statusblock;
NTSTATUS s=STATUS_UNSUCCESSFUL;
InitializeObjectAttributes(&oa, filename, 0, NULL, NULL);
s=ZwCreateFile(&hFile,SYNCHRONIZE|STANDARD_RIGHTS_READ , &oa, &statusblock, NULL, FILE_SYNCHRONOUS_IO_NONALERT| FILE_ATTRIBUTE_NORMAL, 0, FILE_OPEN, 0, NULL, 0);
if (s==STATUS_SUCCESS)
{
s=ZwQueryInformationFile(hFile, &statusblock, &fsi, sizeof(fsi), FileStandardInformation);
if (fsi.EndOfFile.HighPart==0)
{
*size=fsi.EndOfFile.LowPart;
*buffer=ExAllocatePool(PagedPool, fsi.EndOfFile.LowPart); //caller MUST free this
if (*buffer)
{
LARGE_INTEGER ByteOffset;
ByteOffset.QuadPart=0;
s=ZwReadFile(hFile, NULL, NULL, NULL, &statusblock, *buffer, fsi.EndOfFile.LowPart, &ByteOffset, NULL);
if (s==STATUS_PENDING)
s=ZwWaitForSingleObject(hFile, FALSE, NULL);
if (s==STATUS_SUCCESS)
s=statusblock.Status;
if (s!=STATUS_SUCCESS) //read error, free the buffer
ExFreePool(*buffer);
}
}
ZwClose(hFile);
}
return s;
}
NTSTATUS CheckSignature(PVOID buffer, DWORD buffersize, PVOID sig, DWORD sigsize)
/*
Calculates a hash from the buffer and then checks the signature
*/
{
NTSTATUS s=STATUS_UNSUCCESSFUL;
BCRYPT_ALG_HANDLE hashAlgoritm;
s=BCryptOpenAlgorithmProvider(&hashAlgoritm, BCRYPT_SHA512_ALGORITHM, NULL, 0);
if (s==STATUS_SUCCESS)
{
DbgPrint("Created a hash algoritm\n");
if (s==STATUS_SUCCESS)
{
DWORD objectlength;
ULONG size;
s=BCryptGetProperty(hashAlgoritm, BCRYPT_OBJECT_LENGTH, (PUCHAR)&objectlength, sizeof(DWORD), &size, 0);
if (s==STATUS_SUCCESS)
{
BCRYPT_HASH_HANDLE hHash;
PUCHAR pbHashObject=ExAllocatePool(PagedPool, objectlength);
if (pbHashObject)
{
s=BCryptCreateHash(hashAlgoritm, &hHash, pbHashObject, objectlength, (PUCHAR)NULL, 0, 0);
if (s==STATUS_SUCCESS)
{
s=BCryptHashData(hHash, buffer, buffersize, 0);
if (s==STATUS_SUCCESS)
{
DWORD hashlength;
s=BCryptGetProperty(hashAlgoritm, BCRYPT_HASH_LENGTH, (PUCHAR)&hashlength, sizeof(DWORD), &size, 0);
if (s==STATUS_SUCCESS)
{
PUCHAR pbHashBuffer=ExAllocatePool(PagedPool, hashlength);
if (pbHashBuffer)
{
s=BCryptFinishHash(hHash, pbHashBuffer, hashlength, 0);
if (s==STATUS_SUCCESS)
{
BCRYPT_ALG_HANDLE SignAlgoritm;
s=BCryptOpenAlgorithmProvider(&SignAlgoritm, BCRYPT_ECDSA_P521_ALGORITHM, NULL, 0);
if (s==STATUS_SUCCESS)
{
BCRYPT_KEY_HANDLE hKey;
s=BCryptImportKeyPair(SignAlgoritm, 0, BCRYPT_ECCPUBLIC_BLOB, &hKey, publicKey, 140, 0);
if (s==STATUS_SUCCESS)
{
s=BCryptVerifySignature(hKey, NULL, pbHashBuffer, hashlength, sig, sigsize, 0);
if (s==STATUS_SUCCESS)
{
DbgPrint("Valid signature");
}
else
{
//Invalid signature. Wait a bit before returning
LARGE_INTEGER timeout;
timeout.QuadPart=-(LONGLONG)2* 10 * 1000 * 1000; // WDF_REL_TIMEOUT_IN_SEC(2);
KeDelayExecutionThread(UserMode, FALSE, &timeout);
DbgPrint("Signature failure: %x\n", s);
}
BCryptDestroyKey(hKey);
}
else
DbgPrint("ImportKeyPair fail\n");
BCryptCloseAlgorithmProvider(SignAlgoritm,0);
}
else
DbgPrint("OpenSignAlgoritm fail\n");
}
else
DbgPrint("FinishHash Failed\n");
ExFreePool(pbHashBuffer);
}
else
DbgPrint("Failed allocating pbHashBuffer\n");
}
else
DbgPrint("BCRYPT_OBJECT_LENGTH hash failure\n");
}
else
DbgPrint("Failure hashing data\n");
BCryptDestroyHash(hHash);
}
else
DbgPrint("CreateHash failed\n");
ExFreePool(pbHashObject);
}
else
DbgPrint("Failure allocating room for pbHashObject\n");
}
else
DbgPrint("BCRYPT_OBJECT_LENGTH alg failure\n");
}
BCryptCloseAlgorithmProvider(hashAlgoritm,0);
}
else
DbgPrint("Failed getting a hash algoritm\n");
//DbgPrint("returning %x\n", s);
return s;
}
NTSTATUS TestProcess(PIMAGE_DOS_HEADER buf, DWORD size)
{
UINT_PTR maxAddress = (UINT_PTR)buf + size;
if (buf->e_magic != IMAGE_DOS_SIGNATURE)
return STATUS_UNSUCCESSFUL;
if ((DWORD)buf->e_lfanew >= size)
return STATUS_UNSUCCESSFUL;
PIMAGE_NT_HEADERS nth = (PIMAGE_NT_HEADERS)((UINT_PTR)buf + buf->e_lfanew);
if (nth->Signature != IMAGE_NT_SIGNATURE)
return STATUS_UNSUCCESSFUL;
PIMAGE_SECTION_HEADER sections = IMAGE_FIRST_SECTION(nth);
if ((UINT_PTR)sections >= maxAddress)
return STATUS_UNSUCCESSFUL;
int i;
for (i = 0; i < nth->FileHeader.NumberOfSections; i++)
{
if (strcmp((char *)sections[i].Name, ".text") == 0)
{
if (((UINT_PTR)buf + sections[i].PointerToRawData + sections[i].SizeOfRawData) >= maxAddress)
return STATUS_UNSUCCESSFUL;
//BSOD on purpose if this isn't a match
if (RtlCompareMemory((void*)(0x00400000 + sections[i].VirtualAddress), (void*)((UINT_PTR)buf + sections[i].PointerToRawData), sections[i].SizeOfRawData) == sections[i].SizeOfRawData)
{
//seems ok. Confirm the caller is from this .text section
UINT_PTR startaddress;
DWORD length;
if (ZwQueryInformationThread(ZwCurrentThread(), (THREADINFOCLASS)ThreadQuerySetWin32StartAddress, &startaddress, sizeof(startaddress), &length) == STATUS_SUCCESS)
{
if ((startaddress >= (0x00400000 + sections[i].VirtualAddress)) && (startaddress < (0x00400000 + sections[i].VirtualAddress + sections[i].SizeOfRawData)))
return STATUS_SUCCESS;
else
return STATUS_UNSUCCESSFUL;
}
else
return STATUS_UNSUCCESSFUL;
}
else
return STATUS_UNSUCCESSFUL;
}
}
return STATUS_UNSUCCESSFUL;
}
NTSTATUS CheckSignatureOfFile(PUNICODE_STRING originalpath, BOOL isProcess)
{
NTSTATUS s=STATUS_UNSUCCESSFUL;
PVOID file=NULL;
DWORD filesize;
PVOID sig=NULL;
DWORD sigsize;
WCHAR MyBuffer[MAX_PATH*2];
UNICODE_STRING p;
PUNICODE_STRING path=&p;
DbgPrint("CheckSignatureOfFile: ");
p.Buffer=MyBuffer;
p.Length=0;
p.MaximumLength=MAX_PATH*2;
s=RtlUnicodeStringCopy(path, originalpath);
if (s!=STATUS_SUCCESS)
{
DbgPrint("Failure duplicating path: %x\n", s);
return s;
}
s=LoadFile(path, &file, &filesize);
if (s==STATUS_SUCCESS)
{
s=RtlAppendUnicodeToString(path, L".sig");
if (s==STATUS_SUCCESS)
{
s=LoadFile(path, &sig, &sigsize);
if (s==STATUS_SUCCESS)
{
s=CheckSignature(file,filesize,sig,sigsize);
ExFreePool(sig);
if ((s == STATUS_SUCCESS) && isProcess) //one extra check to see if it's actually CE and not just something renamed afterwards
s=TestProcess((PIMAGE_DOS_HEADER)file, filesize);
}
else
DbgPrint("Failure loading %S\n", path->Buffer);
}
ExFreePool(file);
}
else
DbgPrint("Failure loading %S\n", path->Buffer);
//DbgPrint("returning %x\n", s);
return s;
}
NTSTATUS SecurityCheck(void)
/*
Checks the current process for a valid signature
*/
{
NTSTATUS s=STATUS_UNSUCCESSFUL;
char *buffer[MAX_PATH*2+sizeof(UNICODE_STRING)];
PUNICODE_STRING path=(PUNICODE_STRING)&buffer[0];
ULONG length;
if (KeGetCurrentIrql() != PASSIVE_LEVEL)
return STATUS_UNSUCCESSFUL;
if (ZwQueryInformationProcess(ZwCurrentProcess(), ProcessImageFileName, buffer, MAX_PATH*2, &length)==STATUS_SUCCESS)
{
path->MaximumLength=MAX_PATH*2;
s=CheckSignatureOfFile(path,1);
//DbgPrint("returning %x\n", s);
return s;
}
else
return STATUS_UNSUCCESSFUL;
}