CmControlVector from windows 10 build 14279

IoBlockLegacyFsFilters - wut ?

W32pServiceTable from windows 10 build 14279 64bit

W32pServiceLimit .eq. 0x47D

apisetschema.dll from windows 10 build 14279

Several new modules was added:

• onecoreuap-print-render
• onecoreuap-settingsync-status
• win-core-ums
• win-gdi-internal-uap
• net-eap-sim
• win-audiocore-coreaudiopolicymanager
• win-casting-shell
• win-com-psmregister
• win-desktopappx
• win-direct2d-desktop
• win-dx-ddraw
• win-gaming-xinput
• win-kernelbase-packagebreakaway
• win-media-avi
•  win-mf-vfw
• win-ntuser-private
• win-rtcore-ntuser-wmpointer
• win-security-shutdownext
• win-uwf-servicing-apis

lxcore syscall table

I can`t get symbols for lxcore.sys so I just write simple idc scipt. Each item in table has very simple structure:
PAGE:00000001C0046620   imul  r14, r12, 38h      ; size of item in syscall table
PAGE:00000001C0046624   mov   r15, rax
PAGE:00000001C0046627   lea   rax, lx_ssdt
PAGE:00000001C004662E   add   r14, rax
PAGE:00000001C0046631   cmp   r12, 136h          ; count of items in syscall table
PAGE:00000001C0046638   jnb   loc_1C00467AE

string with name of method and arguments located at offset 0x10
IDC script to dump syscall table from lxcore.sys:
#include <idc.idc>

static main(void)
{
  auto addr, name, fp, idx, s_addr;
  fp = fopen("lx.dmp", "w");
  if ( !fp )
  {
    return;
  }
  addr = 0x1C0008110;
  for ( idx = 0; idx < 0x136; idx = idx + 1, addr = addr + 0x38 )
  {
    s_addr = Qword(addr + 0x10);
    fprintf(fp, "%X\t", idx);
    if ( s_addr != 0 )
    {
      // dump string
      for ( ; ; s_addr = s_addr + 1 )
      {
        name = Byte(s_addr);
        if ( !name )
          break;
        fprintf(fp, "%c", name);
      }
    }
    fprintf(fp, "\n");
  }
  fclose(fp);
}
And table itself

CFG with LLVM

On holydays I read book "LLVM Cookbook" (not very good - lots of meaningless copy-pasted code blocks are annoying) and played a bit with fresh llvm-3.7.1 (was released 5 january)

So I decided to check whether it is possible to implement MS CFG in llvm. I have two news - good and bad, as usually

Good: yes, you can easy add instrumentation in llvm - just add some plugin for IR derived from FunctionPass and add call to your guard_check_icall before each VTBL call (or even on any ptr call). I think it will take one day for any CS-student

Bad: you need integration with MS linker and it seems that support of CFG in COFF files is totally undocumented. LLVM itself cannot make load_config and even more - their definition of coff_load_configuration in include\llvm\Object\COFF.h has no fields for CFG (like GuardCFCheckFunctionPointer and GuardCFFunctionTable)

WNF identifiers

I have made a mistake in my previous article about WNF. It seems that WNF idenificators are not standard IID but pair of DWORDs, so struct my_wnf_item actually looks like:
// struct can be ripped from ntdll!RtlpCreateWnfNameSubscription
struct wnf_name
{
/*  0x0 */  DWORD tag; // 0x980912 under x64, 0x700912 under x86
/*  0x4 */  DWORD unk4;
/*  0x8 */  DWORD unk8;
/*  0xC */  DWORD unkC;
/* 0x10 */  DWORD id1;
/* 0x14 */  DWORD id2;
};
 
struct my_wnf_item
{
  LIST_ENTRY List; // linked list of my_wnf_item
  wnf_name *wnfId;
  PBYTE notify;
};

Sample from windows 10 build 10586:
CheckProcess PID 420 (csrss.exe):
PEB.NtGlobalFlag: 0
PEB.Ldr: 00007FF946ED5200
PEB.GdiSharedHandleTable: 000001EFD8BC0000
WnfRoot: 000001EFD8A05BF0
 Wnf[0] at 000001EFD8A08238: id1 A3BC4035 id2 96003D (WNF_PNPA_PORTS_CHANGED_SESSION) - 00007FF943335410 (C:\Windows\system32\winsrv.DLL)
 Wnf[1] at 000001EFD8A080C8: id1 A3BC3875 id2 96003D (WNF_PNPA_PORTS_CHANGED) - 00007FF943335410 (C:\Windows\system32\winsrv.DLL)
 Wnf[2] at 000001EFD8A07F58: id1 A3BC3035 id2 96003D (WNF_PNPA_HARDWAREPROFILES_CHANGED_SESSION) - 00007FF943335410 (C:\Windows\system32\winsrv.DLL)
 Wnf[3] at 000001EFD8A07DE8: id1 A3BC2875 id2 96003D (WNF_PNPA_HARDWAREPROFILES_CHANGED) - 00007FF943335410 (C:\Windows\system32\winsrv.DLL)
 Wnf[4] at 000001EFD8A07C78: id1 A3BC2035 id2 96003D (WNF_PNPA_VOLUMES_CHANGED_SESSION) - 00007FF943335410 (C:\Windows\system32\winsrv.DLL)
 Wnf[5] at 000001EFD8A07B08: id1 A3BC1875 id2 96003D (WNF_PNPA_VOLUMES_CHANGED) - 00007FF943335410 (C:\Windows\system32\winsrv.DLL)
 Wnf[6] at 000001EFD8A04EF8: id1 A3BC1035 id2 96003D (WNF_PNPA_DEVNODES_CHANGED_SESSION) - 00007FF943335410 (C:\Windows\system32\winsrv.DLL)
 Wnf[7] at 000001EFD8A05058: id1 A3BC0875 id2 96003D (WNF_PNPA_DEVNODES_CHANGED) - 00007FF943335410 (C:\Windows\system32\winsrv.DLL)

List of some WNF identifiers (sure is not completed):

W32pServiceTable from windows 10 build 10586 64bit

W32pServiceLimit .eq. 0x46F