如何找到MFC中的消息处理函数（2）-优快云博客

上篇讲的是对程序的定时器消息下断点，如果要拦截用户消息，比如点击按钮等，则需要对消息WM_COMMAND下条件断点，下断点的位置与定时器消息相同，步骤如下：

1 首先找到CWnd::WindowProc函数，进入这个函数以后在函数OnWndMsg前下条件断点，条件为[ebp+8]==WM_COMMAND，代码如下

Code

73D31B77 > 8BFF mov edi, edi ; CWnd::WindowProc

73D31B79 55 push ebp

73D31B7A 8BEC mov ebp, esp

73D31B7C 51 push ecx

73D31B7D 8365 FC 00 and dword ptr [ebp-4], 0

73D31B81 56 push esi

73D31B82 8BF1 mov esi, ecx

73D31B84 8B06 mov eax, dword ptr [esi]

73D31B86 8D4D FC lea ecx, dword ptr [ebp-4]

73D31B89 51 push ecx

73D31B8A FF75 10 push dword ptr [ebp+10]

73D31B8D 8BCE mov ecx, esi

73D31B8F FF75 0C push dword ptr [ebp+C]

73D31B92 FF75 08 push dword ptr [ebp+8] ;此处下条件断点

73D31B95 FF90 A4000000 call dword ptr [eax+A4] ; OnWndMsg

点击程序按钮，断下command消息，F7跟进73D31B95

Code
73D31BC2 >  B8 F1EFDC73     mov     eax, 73DCEFF1                     ; OnWndMsg
73D31BC7    E8 AC100900     call    73DC2C78
73D31BCC    83EC 58         sub     esp, 58
73D31BCF    8365 F0 00      and     dword ptr [ebp-10], 0
73D31BD3    53              push    ebx
73D31BD4    8B5D 08         mov     ebx, dword ptr [ebp+8]
73D31BD7    81FB 11010000   cmp     ebx, 111                          ; WM_COMMAND
73D31BDD    56              push    esi
73D31BDE    57              push    edi
73D31BDF    8BF9            mov     edi, ecx
73D31BE1    75 1B           jnz     short 73D31BFE
73D31BE3    FF75 10         push    dword ptr [ebp+10]
73D31BE6    8B07            mov     eax, dword ptr [edi]
73D31BE8    FF75 0C         push    dword ptr [ebp+C]
73D31BEB    FF90 80000000   call    dword ptr [eax+80]                ; <jmp.&MFC42.#4441_CWnd::OnCommand>

与WM_TIMER消息不通，此时在73D31BE1处不会发生跳转，继续F8到call处，跟进，进入OnCommand函数中，继续F8，直到call函数_CDialog::OnCmdMsg处

Code
73D33234    895D 08         mov     dword ptr [ebp+8>
73D33237    8B06            mov     eax, dword ptr [>
73D33239    53              push    ebx
73D3323A    53              push    ebx
73D3323B    FF75 08         push    dword ptr [ebp+8>
73D3323E    8BCE            mov     ecx, esi
73D33240    57              push    edi
73D33241    FF50 14         call    dword ptr [eax+1>; <jmp.&MFC42.#4425_CDialog::OnCmdMsg>

跟进这个call

Code
73D9DE90 >  8BFF            mov     edi, edi                           ; OnCmdMsg
73D9DE92    55              push    ebp
73D9DE93    8BEC            mov     ebp, esp
73D9DE95    53              push    ebx
73D9DE96    8B5D 08         mov     ebx, dword ptr [ebp+8]
73D9DE99    56              push    esi
73D9DE9A    57              push    edi
73D9DE9B    FF75 14         push    dword ptr [ebp+14]
73D9DE9E    8B7D 0C         mov     edi, dword ptr [ebp+C]
73D9DEA1    FF75 10         push    dword ptr [ebp+10]
73D9DEA4    8BF1            mov     esi, ecx
73D9DEA6    57              push    edi
73D9DEA7    53              push    ebx
73D9DEA8    E8 0844F9FF     call    #4424_CCmdTarget::OnCmdMsg

很快发现了对_CCmdTarget::OnCmdMsg的call，继续跟进，在这个函数中会调用_AfxDispatchCmdMsg对消息进行分发，只要跟进这个函数很快就能找到消息处理函数了，继续F8寻找_AfxDispatchCmdMsg函数

Code
73D323A7    FF75 14         push    dword ptr [ebp+14]
73D323AA    FF70 10         push    dword ptr [eax+10]
73D323AD    FF75 10         push    dword ptr [ebp+10]
73D323B0    FF70 14         push    dword ptr [eax+14]                 ; 消息函数地址
73D323B3    FF75 0C         push    dword ptr [ebp+C]
73D323B6    FF75 08         push    dword ptr [ebp+8]
73D323B9    57              push    edi
73D323BA    E8 7F000000     call    73D3243E

终于找到了，跟进这个call，来到函数_AfxDispatchCmdMsg内部，跟进遇见的第一个call

73D324BA 8B4D 08 mov ecx, dword ptr [ebp + 8 ]
73D324BD FF55 14 call dword ptr [ebp + 14 ] ; MFC42.73D4AAB0

这是一个MFC42领空的调用，进入以后代码如下

73D4AAB0 8B01 mov eax, dword ptr [ecx]
73D4AAB2 - FFA0 CC000000 jmp dword ptr [eax + CC] ; 拦截按钮.004014A0

出现了程序领空了，这里不是用的call，是直接jmp过去的，跟进，消息处理函数终于出来了！哈

Code
004014A0   .  8B41 20       mov     eax, dword ptr [ecx+20]            ;  按钮的消息相应函数
004014A3   .  6A 00         push    0                                  ; /Timerproc = NULL
004014A5   .  68 D0070000   push    7D0                                ; |Timeout = 2000. ms
004014AA   .  6A 02         push    2                                  ; |TimerID = 2
004014AC   .  50            push    eax                                ; |hWnd
004014AD   .  FF15 D0214000 call    dword ptr [<&USER32.SetTimer>]     ; \SetTimer
004014B3   .  C3            retn

消息处理函数很简单，就是调用下定时器，再结合上篇寻找定时器消息相应函数的方法，这个程序的秘密已经完全被消除了，oh yeah！

例程源代码

转载于:https://www.cnblogs.com/feiyucq/archive/2009/07/13/1522665.html