windows deep internals

пятница, 21 апреля 2017 г.

etwex - ida plugin for Etw traces IIDs searching

For example you may need to find which Etw providers located in some module. There are lots of functions can be used to register provider and manual searching is very boring
So I commited today code for Ida Pro plugin for Etw traces IIDs searching. It currently supports only 32bit PE files (much better if you load appropriate PDB file) and processing following functions:

TraceLoggingRegister
TraceLoggingRegisterEx
WPP_INIT_GUID_ARRAY
EtwRegister from import
EtwEventRegister from import
EventRegister from import

Samples of using:

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четверг, 6 апреля 2017 г.

ntdll ProtectedPolicies

It seems that since windows 10 ntdll has security feature called "ProtectedPolicies" - you can query it with RtlQueryProtectedPolicy function. Prototype of this function is:
NTAPI NTSTATUS RtlQueryProtectedPolicy(GUID *, PDWORD out_flag);

Lets see how it works:

loc_6A277EFB:   ; CODE XREF: RtlQueryProtectedPolicy(x,x)+12 j
  push    edi
  mov     edi, offset _RtlpProtectedPoliciesSRWLock
  push    edi
  call    _RtlAcquireSRWLockShared@4    ; RtlAcquireSRWLockShared(x)
  push    offset _RtlpSearchProtectedPolicyEntry ; PtFuncCompare
  push    14h                           ; SizeOfElements
  push    ds:_RtlpProtectedPoliciesActiveCount ; NumOfElements
  push    ds:_RtlpProtectedPolicies     ; Base
  push    [ebp+Key]                     ; Key
  call    _bsearch

That policies stored in array RtlpProtectedPolicies, count located in RtlpProtectedPoliciesActiveCount and size of each policy is 0x14 bytes (0x18 under x64), so each policy looks like struct:
struct protected_policy
{
IID guid;
DWORD flag;
};

Lets see from where RtlQueryProtectedPolicy called

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четверг, 2 марта 2017 г.

ida plugin for RFG fixups processing

I commited today code for Ida Pro plugin for RFG fixups processing - for both version 1 & 2

It seems that by default during automatic loading of pe files Ida don`t load .reloc section (where usually located RFG fixups). In such case I ask if you want to add new segment:

Sure it works only if original input file (you can extract it with get_input_file_path function) is still available. Also I used dirty hack - I am too lazy to parse PE file by hand, and it seems that node "$ PE header" keeps all sections (even not loaded in base !) in supvals

enjoy

Update: it seems that buggy ida sdk don`t contains doCode function and auto_mark_range actually does not take into account end argument, so body of prologs looks ugly

среда, 1 марта 2017 г.

IMAGE_DYNAMIC_RELOCATION_TABLE.Version 2

it seems that around since w10 build 15007 format of rfg relocs was changed and field IMAGE_DYNAMIC_RELOCATION_TABLE.Version now has value 2. So lets install platform SDK for 15003 and see what was changed

First remarkable thing is that IMAGE_LOAD_CONFIG_DIRECTORY now has two additional fields:

    WORD       DynamicValueRelocTableSection;
    WORD       Reserved2;
    // since w10 build 15003 ?
    ULONGLONG  GuardRFVerifyStackPointerFunctionPointer; // VA
    DWORD      HotPatchTableOffset;

} IMAGE_LOAD_CONFIG_DIRECTORY64, *PIMAGE_LOAD_CONFIG_DIRECTORY64;

so sizeof(IMAGE_LOAD_CONFIG_DIRECTORY64) is now 0xf4

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