如何在内核转储中获取Section对象的内容 [英] How to get the content of a Section object in a kernel dump

问题描述

第3Party供应商的section对象名为rpsPdf10.mutex，其预期用途是通过向其写入布尔标志来模拟信号量.

The section object from a 3thParty vendor is named rpsPdf10.mutex and it's intended use is to mimic a semaphore by writing a Boolean flag to it.

使用LiveKd并在SO的帮助下，我发布了以下命令，以获取此Section对象的详细信息.

Using LiveKd and with a lot of help from SO, I've issued following command's trying to get detailed info of this Section object.

0: kd>!process 0 0 3thParty.exe
...
PROCESS fffffa800ea80060
    SessionId: 0  Cid: 0a00    Peb: fffdf000  ParentCid: 014c
    DirBase: 99349000  ObjectTable: fffff8a004448bf0  HandleCount: 338.
    Image: 3thParty.exe
...    

0: kd> !handle 0 7 fffffa800ea80060
         ...
         08  fffff8a012e26710 Section                   rpsPdf10.mutex
         ...

0: kd> !object fffff8a012e26710
Object: fffff8a012e26710  Type: (fffffa800cd7cea0) Section
    ObjectHeader: fffff8a012e266e0 (new version)
    HandleCount: 38  PointerCount: 39
    Directory Object: fffff8a00a980080  Name: rpsPdf10.mutex

0: kd> dt -r1 nt!_SECTION_OBJECT 0xfffff8a012e26710
   +0x000 StartingVa       : 0x00000022`00000100 Void
   +0x008 EndingVa         : 0x00000000`0008dfb0 Void
   +0x010 Parent           : 0xfffffa80`c0000001 Void
   +0x018 LeftChild        : (null) 
   +0x020 RightChild       : 0xfffffa80`00000034 Void
   +0x028 Segment          : 0xfffff8a0`102d7820 _SEGMENT_OBJECT
      +0x000 BaseAddress      : 0xfffffa80`0fbed900 Void
      +0x008 TotalNumberOfPtes : 1
      +0x010 SizeOfSegment    : _LARGE_INTEGER 0x1
      +0x018 NonExtendedPtes  : 0x1000
      +0x01c ImageCommitment  : 0
      +0x020 ControlArea      : (null) 
      +0x028 Subsection       : (null) 
      +0x030 MmSectionFlags   : 0xfffffa80`10987b10 _MMSECTION_FLAGS
      +0x038 MmSubSectionFlags : 0x00000000`03400000 _MMSUBSECTION_FLAGS

所有这些对我来说都是正确的，但是如何找到该部分的内容?

All this looks correct to me but how can I find the content the section?

推荐答案

要注意的地方，如

points to note as in earlier answer machine is 32 bit and os is win7 and windbg version is insider preview 16278 commands are arch agnostic and pointer arithmetic if any are arch dependent
and the walk through is on live binary not in a dump as there is a very fair chance that the page might have been paged out in the dump and demo might be inconclusive i might add to this answer later

获取内容表单部分有点麻烦
(有几种类型的Section，如
1)ALPC部分(com对象)
2)文件支持的部分
3)PageFileBacked节等

getting contents form section is kinda convoluted
(there are several types of Section like
1) ALPC section(com objects )
2) File backed Section
3) PageFileBacked Section etc

下面的演练是针对页面文件支持的部分(最常见的类型)

the walkthrough below is for a pagefile backed section (most common type)

假设您编译并执行了以下代码
exe将在全局命名空间中创建SectionObject.
内容将由PagingFile支持，并正在等待 按键

Assuming you compiled and executed the code below
the exe will create a SectionObject in global namespace
and the contents will be backed by PagingFile and will be waiting for a keypress

#include <windows.h>
#include <stdio.h>
#define bsize 256
int main(){
    char szMsg[]={"Message from blabb to lieven from Stack Overflow."};
    int ret = NULL;
    HANDLE hMap = CreateFileMapping((HANDLE)-1,NULL,4,0,bsize,"Global\\MyMap");
    if(hMap){
        PCHAR buff = (PCHAR) MapViewOfFile(hMap,0xf001f,0,0,bsize);
        if(buff){
            CopyMemory(buff, szMsg, sizeof(szMsg));
            ret = getchar();
            UnmapViewOfFile(buff);
        }
        CloseHandle(hMap);
    }
    return ret;
}

假设进程正在等待按键启动livekd或建立实时内核调试连接(如果该进程正在远程计算机/vm中运行)

assuming the process is waiting for a keypress launch livekd or setup a live kernel debugging connection if it is running in a remote machine / vm

C:> livekd -k"c:\ Program Files \ Windows Kits \ 10 \ Debuggers \ x86 \ cdb.exe"

LiveKd v5.62 - Execute kd/windbg on a live system
Launching c:\Program Files\Windows Kits\10\Debuggers\x86\cdb.exe:

Microsoft (R) Windows Debugger Version 10.0.16278.1000 X86

获取_EPROCESS并设置上下文

get the the _EPROCESS and set context

kd> !process 0 0 secobj.exe

PROCESS 8605ab28  SessionId: 1  Cid: 0fbc    Peb: 7ffd9000  ParentCid: 0af4
    DirBase: 7e2712e0  ObjectTable: c288ba00  HandleCount:   9.
    Image: secobj.exe

kd> .process /p /r 8605ab28

Implicit process is now 8605ab28

kd> ? @$proc
Evaluate expression: -2046448856 = 8605ab28

kd> ?? (char *)@$proc->ImageFileName
char * 0x8605ac94
 "secobj.exe"

在当前流程通知中查找"Section"类型的句柄，因为 在我们使用的全局名称空间windbg解密中命名该部分

look for a handle of type Section in the current process notice since our section is named in global namespace windbg deciphers that for us

kd> !handle 0 3 @$proc Section

Searching for handles of type Section

PROCESS 8605ab28  SessionId: 1  Cid: 0fbc    Peb: 7ffd9000  ParentCid: 0af4
    DirBase: 7e2712e0  ObjectTable: c288ba00  HandleCount:   9.
    Image: secobj.exe

Handle table at c288ba00 with 9 entries in use

0024: Object: c238e9c8  GrantedAccess: 000f0007 Entry: c37b7048
Object: c238e9c8  Type: (84ec6040) Section
    ObjectHeader: c238e9b0 (new version)
        HandleCount: 1 PointerCount: 2
        Directory Object: 98a0f170  Name: MyMap

转储SectionObject

dumping the SectionObject

kd> dt nt!_SECTION_OBJECT c238e9c8
   +0x000 StartingVa       : 0xc227e2c8 Void
   +0x004 EndingVa         : 0x00d3db6c Void
   +0x008 Parent           : 0xb0d3db20 Void
   +0x00c LeftChild        : (null)
   +0x010 RightChild       : 0x00000003 Void
   +0x014 Segment          : 0xc36aba20 _SEGMENT_OBJECT

kd> $$请注意，最后一个细分受众群成员不是SEGMENT_OBJECT，而是
nt！_segment或实际上是指向此部分的ControlArea的指针

kd> $$ Notice the Last Segment member it is not SEGMENT_OBJECT but
nt!_segment or actually a pointer to ControlArea for this Section

kd> dt nt!_SEGMENT 0xc36aba20
   +0x000 ControlArea      : 0x85182d08 _CONTROL_AREA
   +0x004 TotalNumberOfPtes : 1
   +0x008 SegmentFlags     : _SEGMENT_FLAGS
   +0x00c NumberOfCommittedPages : 1
   +0x010 SizeOfSegment    : 0x1000
   +0x018 ExtendInfo       : (null)
   +0x018 BasedAddress     : (null)
   +0x01c SegmentLock      : _EX_PUSH_LOCK
   +0x020 u1               : <unnamed-tag>
   +0x024 u2               : <unnamed-tag>
   +0x028 PrototypePte     : 0xc36aba50 _MMPTE
   +0x030 ThePtes          : [1] _MMPTE

kd> $$，您可以展开联合u2并转储联合的FirstMappedVa以查看此部分的内容

kd> dt nt!_SEGMENT u2.FirstMappedVa 0xc36aba20
   +0x024 u2               :
      +0x000 FirstMappedVa    : 0x000e0000 Void

转储内容

kd> da 0xe0000
000e0000  "Message from blabb to lieven fro"
000e0020  "m Stack Overflow."
kd>

或执行！ca获取指向第一页的FirstMappedVa
如果内容大于一页边界，则获取它们是
有点乏味，因为它们可能已被调出页面并需要执行 操作，从而解决了页面错误，使它们可见

or do !ca to get the FirstMappedVa which points to the first page
if the contents are greater than one page boundary fetching them is
kinda tedious as they may have been paged out and would need an execution operation and thus a page fault handled to get them into view

kd> !ca poi(0xc36aba20)

ControlArea  @ 85182d08
  Segment      c36aba20  Flink      00000000  Blink        00000000
  Section Ref         1  Pfn Ref           0  Mapped Views        1
  User Ref            2  WaitForDel        0  Flush Count         0
  File Object  00000000  ModWriteCount     0  System Views        0
  WritableRefs        0
  Flags (2000) Commit

      Pagefile-backed section

Segment @ c36aba20
  ControlArea       85182d08  ExtendInfo    00000000
  Total Ptes               1
  Segment Size          1000  Committed            1
  CreatingProcess   8605ab28  FirstMappedVa    e0000 <-------------
  ProtoPtes         c36aba50
  Flags (80000) ProtectionMask

Subsection 1 @ 85182d58
  ControlArea  85182d08  Starting Sector        0  Number Of Sectors    0
  Base Pte     c36aba50  Ptes In Subsect        1  Unused Ptes          0
  Flags               8  Sector Offset          0  Protection           4
kd>

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