I am working on a c++ project where i need to inject our DLL into a target process. I am able to inject our dll in some of the target processes however i am not able to inject it fully into the target process. So the functionality of target process is not working at full.

I have took the refrence for injection methods from https://github.com/stephenfewer/ReflectiveDLLInjection.

EXPORT  ULONG_PTR WINAPI ExampleLoader( LPVOID lpParameter )
{
// the functions we need`
LOADLIBRARYA pLoadLibraryA     = NULL;
GETPROCADDRESS pGetProcAddress = NULL;
VIRTUALALLOC pVirtualAlloc     = NULL;
NTFLUSHINSTRUCTIONCACHE pNtFlushInstructionCache = NULL;

    USHORT usCounter;
    
    // the initial location of this image in memory
    ULONG_PTR uiLibraryAddress;
    // the kernels base address and later this images newly loaded base address
    ULONG_PTR uiBaseAddress;
    
    // variables for processing the kernels export table
    ULONG_PTR uiAddressArray;
    ULONG_PTR uiNameArray;
    ULONG_PTR uiExportDir;
    ULONG_PTR uiNameOrdinals;
    DWORD dwHashValue;
    
    // variables for loading this image
    ULONG_PTR uiHeaderValue;
    ULONG_PTR uiValueA;
    ULONG_PTR uiValueB;
    ULONG_PTR uiValueC;
    ULONG_PTR uiValueD;
    ULONG_PTR uiValueE;
    
    // STEP 0: calculate our images current base address
    
    // we will start searching backwards from our callers return address.
    uiLibraryAddress = caller();
    
    // loop through memory backwards searching for our images base address
    // we dont need SEH style search as we shouldnt generate any access violations with this
    while( TRUE )
    {
        if( ((PIMAGE_DOS_HEADER)uiLibraryAddress)->e_magic == IMAGE_DOS_SIGNATURE )
        {
            uiHeaderValue = ((PIMAGE_DOS_HEADER)uiLibraryAddress)->e_lfanew;
            // some x64 dll's can trigger a bogus signature (IMAGE_DOS_SIGNATURE == 'POP r10'),
            // we sanity check the e_lfanew with an upper threshold value of 1024 to avoid problems.
            if( uiHeaderValue >= sizeof(IMAGE_DOS_HEADER) && uiHeaderValue < 1024 )
            {
                uiHeaderValue += uiLibraryAddress;
                // break if we have found a valid MZ/PE header
                if( ((PIMAGE_NT_HEADERS)uiHeaderValue)->Signature == IMAGE_NT_SIGNATURE )
                    break;
            }
        }
        uiLibraryAddress--;
    }
    
    // STEP 1: process the kernels exports for the functions our loader needs...
    
    // get the Process Enviroment Block

#ifdef WIN_X64
uiBaseAddress = __readgsqword( 0x60 );
#else
#ifdef WIN_X86
uiBaseAddress = __readfsdword( 0x30 );
#else WIN_ARM
uiBaseAddress = __readgsqword( 0x60 );
#endif
#endif

    // get the processes loaded modules. ref: http://msdn.microsoft.com/en-us/library/aa813708(VS.85).aspx
    uiBaseAddress = (ULONG_PTR)((_PPEB)uiBaseAddress)->pLdr;
    
    // get the first entry of the InMemoryOrder module list
    uiValueA = (ULONG_PTR)((PPEB_LDR_DATA)uiBaseAddress)->InMemoryOrderModuleList.Flink;
    while( uiValueA )
    {
        // get pointer to current modules name (unicode string)
        uiValueB = (ULONG_PTR)((PLDR_DATA_TABLE_ENTRY)uiValueA)->BaseDllName.pBuffer;
        // set bCounter to the length for the loop
        usCounter = ((PLDR_DATA_TABLE_ENTRY)uiValueA)->BaseDllName.Length;
        // clear uiValueC which will store the hash of the module name
        uiValueC = 0;
    
        // compute the hash of the module name...
        do
        {
            uiValueC = ror( (DWORD)uiValueC );
            // normalize to uppercase if the madule name is in lowercase
            if( *((BYTE *)uiValueB) >= 'a' )
                uiValueC += *((BYTE *)uiValueB) - 0x20;
            else
                uiValueC += *((BYTE *)uiValueB);
            uiValueB++;
        } while( --usCounter );
    
        // compare the hash with that of kernel32.dll
        if( (DWORD)uiValueC == KERNEL32DLL_HASH )
        {
            // get this modules base address
            uiBaseAddress = (ULONG_PTR)((PLDR_DATA_TABLE_ENTRY)uiValueA)->DllBase;
    
            // get the VA of the modules NT Header
            uiExportDir = uiBaseAddress + ((PIMAGE_DOS_HEADER)uiBaseAddress)->e_lfanew;
    
            // uiNameArray = the address of the modules export directory entry
            uiNameArray = (ULONG_PTR)&((PIMAGE_NT_HEADERS)uiExportDir)->OptionalHeader.DataDirectory[ IMAGE_DIRECTORY_ENTRY_EXPORT ];
    
            // get the VA of the export directory
            uiExportDir = ( uiBaseAddress + ((PIMAGE_DATA_DIRECTORY)uiNameArray)->VirtualAddress );
    
            // get the VA for the array of name pointers
            uiNameArray = ( uiBaseAddress + ((PIMAGE_EXPORT_DIRECTORY )uiExportDir)->AddressOfNames );
            
            // get the VA for the array of name ordinals
            uiNameOrdinals = ( uiBaseAddress + ((PIMAGE_EXPORT_DIRECTORY )uiExportDir)->AddressOfNameOrdinals );
    
            usCounter = 3;
    
            // loop while we still have imports to find
            while( usCounter > 0 )
            {
                // compute the hash values for this function name
                dwHashValue = ::hash( (char *)( uiBaseAddress + DEREF_32( uiNameArray ) )  );
                
                // if we have found a function we want we get its virtual address
                if( dwHashValue == LOADLIBRARYA_HASH || dwHashValue == GETPROCADDRESS_HASH || dwHashValue == VIRTUALALLOC_HASH )
                {
                    // get the VA for the array of addresses
                    uiAddressArray = ( uiBaseAddress + ((PIMAGE_EXPORT_DIRECTORY )uiExportDir)->AddressOfFunctions );
    
                    // use this functions name ordinal as an index into the array of name pointers
                    uiAddressArray += ( DEREF_16( uiNameOrdinals ) * sizeof(DWORD) );
    
                    // store this functions VA
                    if( dwHashValue == LOADLIBRARYA_HASH )
                        pLoadLibraryA = (LOADLIBRARYA)( uiBaseAddress + DEREF_32( uiAddressArray ) );
                    else if( dwHashValue == GETPROCADDRESS_HASH )
                        pGetProcAddress = (GETPROCADDRESS)( uiBaseAddress + DEREF_32( uiAddressArray ) );
                    else if( dwHashValue == VIRTUALALLOC_HASH )
                        pVirtualAlloc = (VIRTUALALLOC)( uiBaseAddress + DEREF_32( uiAddressArray ) );
            
                    // decrement our counter
                    usCounter--;
                }
    
                // get the next exported function name
                uiNameArray += sizeof(DWORD);
    
                // get the next exported function name ordinal
                uiNameOrdinals += sizeof(WORD);
            }
        }
        else if( (DWORD)uiValueC == NTDLLDLL_HASH )
        {
            // get this modules base address
            uiBaseAddress = (ULONG_PTR)((PLDR_DATA_TABLE_ENTRY)uiValueA)->DllBase;
    
            // get the VA of the modules NT Header
            uiExportDir = uiBaseAddress + ((PIMAGE_DOS_HEADER)uiBaseAddress)->e_lfanew;
    
            // uiNameArray = the address of the modules export directory entry
            uiNameArray = (ULONG_PTR)&((PIMAGE_NT_HEADERS)uiExportDir)->OptionalHeader.DataDirectory[ IMAGE_DIRECTORY_ENTRY_EXPORT ];
    
            // get the VA of the export directory
            uiExportDir = ( uiBaseAddress + ((PIMAGE_DATA_DIRECTORY)uiNameArray)->VirtualAddress );
    
            // get the VA for the array of name pointers
            uiNameArray = ( uiBaseAddress + ((PIMAGE_EXPORT_DIRECTORY )uiExportDir)->AddressOfNames );
            
            // get the VA for the array of name ordinals
            uiNameOrdinals = ( uiBaseAddress + ((PIMAGE_EXPORT_DIRECTORY )uiExportDir)->AddressOfNameOrdinals );
    
            usCounter = 1;
    
            // loop while we still have imports to find
            while( usCounter > 0 )
            {
                // compute the hash values for this function name
                dwHashValue = ::hash( (char *)( uiBaseAddress + DEREF_32( uiNameArray ) )  );
                
                // if we have found a function we want we get its virtual address
                if( dwHashValue == NTFLUSHINSTRUCTIONCACHE_HASH )
                {
                    // get the VA for the array of addresses
                    uiAddressArray = ( uiBaseAddress + ((PIMAGE_EXPORT_DIRECTORY )uiExportDir)->AddressOfFunctions );
    
                    // use this functions name ordinal as an index into the array of name pointers
                    uiAddressArray += ( DEREF_16( uiNameOrdinals ) * sizeof(DWORD) );
    
                    // store this functions VA
                    if( dwHashValue == NTFLUSHINSTRUCTIONCACHE_HASH )
                        pNtFlushInstructionCache = (NTFLUSHINSTRUCTIONCACHE)( uiBaseAddress + DEREF_32( uiAddressArray ) );
    
                    // decrement our counter
                    usCounter--;
                }
    
                // get the next exported function name
                uiNameArray += sizeof(DWORD);
    
                // get the next exported function name ordinal
                uiNameOrdinals += sizeof(WORD);
            }
        }
    
        // we stop searching when we have found everything we need.
        if( pLoadLibraryA && pGetProcAddress && pVirtualAlloc && pNtFlushInstructionCache )
            break;
    
        // get the next entry
        uiValueA = DEREF( uiValueA );
    }
    
    // STEP 2: load our image into a new permanent location in memory...
    
    // get the VA of the NT Header for the PE to be loaded
    uiHeaderValue = uiLibraryAddress + ((PIMAGE_DOS_HEADER)uiLibraryAddress)->e_lfanew;
    
    // allocate all the memory for the DLL to be loaded into. we can load at any address because we will  
    // relocate the image. Also zeros all memory and marks it as READ, WRITE and EXECUTE to avoid any problems.
    uiBaseAddress = (ULONG_PTR)pVirtualAlloc( NULL, ((PIMAGE_NT_HEADERS)uiHeaderValue)->OptionalHeader.SizeOfImage, MEM_RESERVE|MEM_COMMIT, PAGE_EXECUTE_READWRITE );
    
    // we must now copy over the headers
    uiValueA = ((PIMAGE_NT_HEADERS)uiHeaderValue)->OptionalHeader.SizeOfHeaders;
    uiValueB = uiLibraryAddress;
    uiValueC = uiBaseAddress;
    
    while( uiValueA-- )
        *(BYTE *)uiValueC++ = *(BYTE *)uiValueB++;
    
    // STEP 3: load in all of our sections...
    
    // uiValueA = the VA of the first section
    uiValueA = ( (ULONG_PTR)&((PIMAGE_NT_HEADERS)uiHeaderValue)->OptionalHeader + ((PIMAGE_NT_HEADERS)uiHeaderValue)->FileHeader.SizeOfOptionalHeader );
    
    // itterate through all sections, loading them into memory.
    uiValueE = ((PIMAGE_NT_HEADERS)uiHeaderValue)->FileHeader.NumberOfSections;
    while( uiValueE-- )
    {
        // uiValueB is the VA for this section
        uiValueB = ( uiBaseAddress + ((PIMAGE_SECTION_HEADER)uiValueA)->VirtualAddress );
    
        // uiValueC if the VA for this sections data
        uiValueC = ( uiLibraryAddress + ((PIMAGE_SECTION_HEADER)uiValueA)->PointerToRawData );
    
        // copy the section over
        uiValueD = ((PIMAGE_SECTION_HEADER)uiValueA)->SizeOfRawData;
    
        while( uiValueD-- )
            *(BYTE *)uiValueB++ = *(BYTE *)uiValueC++;
    
        // get the VA of the next section
        uiValueA += sizeof( IMAGE_SECTION_HEADER );
    }
    
    // STEP 4: process our images import table...
    
    // uiValueB = the address of the import directory
    uiValueB = (ULONG_PTR)&((PIMAGE_NT_HEADERS)uiHeaderValue)->OptionalHeader.DataDirectory[ IMAGE_DIRECTORY_ENTRY_IMPORT ];
    
    // we assume their is an import table to process
    // uiValueC is the first entry in the import table
    uiValueC = ( uiBaseAddress + ((PIMAGE_DATA_DIRECTORY)uiValueB)->VirtualAddress );
    
    // itterate through all imports
    while( ((PIMAGE_IMPORT_DESCRIPTOR)uiValueC)->Name )
    {
        // use LoadLibraryA to load the imported module into memory
        uiLibraryAddress = (ULONG_PTR)pLoadLibraryA( (LPCSTR)( uiBaseAddress + ((PIMAGE_IMPORT_DESCRIPTOR)uiValueC)->Name ) );
    
        // uiValueD = VA of the OriginalFirstThunk
        uiValueD = ( uiBaseAddress + ((PIMAGE_IMPORT_DESCRIPTOR)uiValueC)->OriginalFirstThunk );
    
        // uiValueA = VA of the IAT (via first thunk not origionalfirstthunk)
        uiValueA = ( uiBaseAddress + ((PIMAGE_IMPORT_DESCRIPTOR)uiValueC)->FirstThunk );
    
        // itterate through all imported functions, importing by ordinal if no name present
        while( DEREF(uiValueA) )
        {
            // sanity check uiValueD as some compilers only import by FirstThunk
            if( uiValueD && ((PIMAGE_THUNK_DATA)uiValueD)->u1.Ordinal & IMAGE_ORDINAL_FLAG )
            {
                // get the VA of the modules NT Header
                uiExportDir = uiLibraryAddress + ((PIMAGE_DOS_HEADER)uiLibraryAddress)->e_lfanew;
    
                // uiNameArray = the address of the modules export directory entry
                uiNameArray = (ULONG_PTR)&((PIMAGE_NT_HEADERS)uiExportDir)->OptionalHeader.DataDirectory[ IMAGE_DIRECTORY_ENTRY_EXPORT ];
    
                // get the VA of the export directory
                uiExportDir = ( uiLibraryAddress + ((PIMAGE_DATA_DIRECTORY)uiNameArray)->VirtualAddress );
    
                // get the VA for the array of addresses
                uiAddressArray = ( uiLibraryAddress + ((PIMAGE_EXPORT_DIRECTORY )uiExportDir)->AddressOfFunctions );
    
                // use the import ordinal (- export ordinal base) as an index into the array of addresses
                uiAddressArray += ( ( IMAGE_ORDINAL( ((PIMAGE_THUNK_DATA)uiValueD)->u1.Ordinal ) - ((PIMAGE_EXPORT_DIRECTORY )uiExportDir)->Base ) * sizeof(DWORD) );
    
                // patch in the address for this imported function
                DEREF(uiValueA) = ( uiLibraryAddress + DEREF_32(uiAddressArray) );
            }
            else
            {
                // get the VA of this functions import by name struct
                uiValueB = ( uiBaseAddress + DEREF(uiValueA) );
    
                // use GetProcAddress and patch in the address for this imported function
                DEREF(uiValueA) = (ULONG_PTR)pGetProcAddress( (HMODULE)uiLibraryAddress, (LPCSTR)((PIMAGE_IMPORT_BY_NAME)uiValueB)->Name );
            }
            // get the next imported function
            uiValueA += sizeof( ULONG_PTR );
            if( uiValueD )
                uiValueD += sizeof( ULONG_PTR );
        }
    
        // get the next import
        uiValueC += sizeof( IMAGE_IMPORT_DESCRIPTOR );
    }
    
    // STEP 5: process all of our images relocations...
    
    // calculate the base address delta and perform relocations (even if we load at desired image base)
    uiLibraryAddress = uiBaseAddress - ((PIMAGE_NT_HEADERS)uiHeaderValue)->OptionalHeader.ImageBase;
    
    // uiValueB = the address of the relocation directory
    uiValueB = (ULONG_PTR)&((PIMAGE_NT_HEADERS)uiHeaderValue)->OptionalHeader.DataDirectory[ IMAGE_DIRECTORY_ENTRY_BASERELOC ];
    
    // check if their are any relocations present
    if( ((PIMAGE_DATA_DIRECTORY)uiValueB)->Size )
    {
        // uiValueC is now the first entry (IMAGE_BASE_RELOCATION)
        uiValueC = ( uiBaseAddress + ((PIMAGE_DATA_DIRECTORY)uiValueB)->VirtualAddress );
    
        // and we itterate through all entries...
        while( ((PIMAGE_BASE_RELOCATION)uiValueC)->SizeOfBlock )
        {
            // uiValueA = the VA for this relocation block
            uiValueA = ( uiBaseAddress + ((PIMAGE_BASE_RELOCATION)uiValueC)->VirtualAddress );
    
            // uiValueB = number of entries in this relocation block
            uiValueB = ( ((PIMAGE_BASE_RELOCATION)uiValueC)->SizeOfBlock - sizeof(IMAGE_BASE_RELOCATION) ) / sizeof( IMAGE_RELOC );
    
            // uiValueD is now the first entry in the current relocation block
            uiValueD = uiValueC + sizeof(IMAGE_BASE_RELOCATION);
    
            // we itterate through all the entries in the current block...
            while( uiValueB-- )
            {
                // perform the relocation, skipping IMAGE_REL_BASED_ABSOLUTE as required.
                // we dont use a switch statement to avoid the compiler building a jump table
                // which would not be very position independent!
                if( ((PIMAGE_RELOC)uiValueD)->type == IMAGE_REL_BASED_DIR64 )
                    *(ULONG_PTR *)(uiValueA + ((PIMAGE_RELOC)uiValueD)->offset) += uiLibraryAddress;
                else if( ((PIMAGE_RELOC)uiValueD)->type == IMAGE_REL_BASED_HIGHLOW )
                    *(DWORD *)(uiValueA + ((PIMAGE_RELOC)uiValueD)->offset) += (DWORD)uiLibraryAddress;
    
                else if( ((PIMAGE_RELOC)uiValueD)->type == IMAGE_REL_BASED_HIGH )
                    *(WORD *)(uiValueA + ((PIMAGE_RELOC)uiValueD)->offset) += HIWORD(uiLibraryAddress);
                else if( ((PIMAGE_RELOC)uiValueD)->type == IMAGE_REL_BASED_LOW )
                    *(WORD *)(uiValueA + ((PIMAGE_RELOC)uiValueD)->offset) += LOWORD(uiLibraryAddress);
    
                // get the next entry in the current relocation block
                uiValueD += sizeof( IMAGE_RELOC );
            }
    
            // get the next entry in the relocation directory
            uiValueC = uiValueC + ((PIMAGE_BASE_RELOCATION)uiValueC)->SizeOfBlock;
        }
    }
    
    // STEP 6: call our images entry point
    
    // uiValueA = the VA of our newly loaded DLL/EXE's entry point
    uiValueA = ( uiBaseAddress + ((PIMAGE_NT_HEADERS)uiHeaderValue)->OptionalHeader.AddressOfEntryPoint );
    
    // We must flush the instruction cache to avoid stale code being used which was updated by our relocation processing.
    pNtFlushInstructionCache( (HANDLE)-1, NULL, 0 );
    
    // call our respective entry point, fudging our hInstance value

((DLLMAIN)uiValueA)( (HINSTANCE)uiBaseAddress, DLL_PROCESS_ATTACH, lpParameter );
// STEP 8: return our new entry point address so whatever called us can call DllMain() if needed.
return uiValueA;
}

I have tried to put the above method in our DLL and other rest of the code while trying to load this dll in the target process some of the exes are not getting injected by this code ?

Can you suggest what i am doing wrong here ?

I am using Visual Studio 2010 for this.