flash player版本号：14.0.0.125

产品名称：Adobe® Flash® Player Installer/Uninstaller

系统：windows xp sp3

调试器：windbg

反汇编器：IDA

应用程序：FlashUtil32_14_0_0_125_Plugin.exe

coredump信息：

eax=00000000 ebx=01ed75f0 ecx=00000000 edx=00000000 esi=01ed75f0 edi=00000000eip=00409db5 esp=0012fc1c ebp=0012fc30 iopl=0         nv up ei pl zr na pe nccs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             efl=00200246FlashUtil32_14_0_0_125_Plugin+0x9db5:00409db5 f7f1            div     eax,ecx

堆栈：

0:000> kbChildEBP RetAddr  Args to Child              WARNING: Stack unwind information not available. Following frames may be wrong.0012fc30 0040c1e6 00000001 00000064 00000000 FlashUtil32_14_0_0_125_Plugin+0x9db50012fcd0 77d18734 00010652 00000464 00000001 FlashUtil32_14_0_0_125_Plugin+0xc1e60012fcfc 77d18816 0040c190 00010652 00000464 USER32!GetDC+0x6d0012fd64 77d189cd 00000000 0040c190 00010652 USER32!GetDC+0x14f0012fdc4 77d18a10 0012fdec 00000000 0012fe0c USER32!GetWindowLongW+0x1270012fdd4 0040c5c9 0012fdec 0042c0b8 01be42b8 USER32!DispatchMessageW+0xf0012fe0c 00406975 01be2ad8 01be42b8 01be2d80 FlashUtil32_14_0_0_125_Plugin+0xc5c90012fe80 00404b5b 0040150e 01be2a08 00404ba7 FlashUtil32_14_0_0_125_Plugin+0x69750012fe84 0040150e 01be2a08 00404ba7 01be2ad8 FlashUtil32_14_0_0_125_Plugin+0x4b5b0012fe8c 00404ba7 01be2ad8 01be42b8 01be2d80 FlashUtil32_14_0_0_125_Plugin+0x150e0012feb8 0040120a 01ed7298 01eeefc8 00000000 FlashUtil32_14_0_0_125_Plugin+0x4ba700000000 00000000 00000000 00000000 00000000 FlashUtil32_14_0_0_125_Plugin+0x120a

从“coredump信息”里能够。 因为ecx=00000000所以导致div     eax,ecx出现除0异常。

那么，ecx的值是从哪里来呢？

用IDA打开FlashUtil32_14_0_0_125_Plugin.exe，跳转到地址00409db5，能够看到：

.text:00409DA4 loc_409DA4:                             ; CODE XREF: sub_4099CA+2BEj.text:00409DA4                 mov     edi, [ebp+arg_8].text:00409DA7                 movzx   ecx, word ptr [ebp+arg_8].text:00409DAB                 shr     edi, 10h.text:00409DAE                 mov     eax, edi.text:00409DB0                 imul    eax, 64h.text:00409DB3                 xor     edx, edx.text:00409DB5                 div     ecx

由上面代码片段。能够看出，ecx的值是由00409db5所在函数的第三个參数赋值的。看一下第三个參数是多少？

0:000> dd ebp L 80012fc30  0012fcd0 0040c1e6 00000001 000000640012fc40  00000000 0012fd38 0040c190 00000000

从这里看到。第三个參数也是0（地址0012fc40的值）。那么，第三个參数的值又是从哪里来的？

看一下上一层函数（地址0040c1e6所在的函数）：

.text:0040C190 ; LRESULT __stdcall PrevWndFunc(HWND, UINT, WPARAM, LPARAM).text:0040C190 PrevWndFunc     proc near               ; DATA XREF: sub_40C605+4Ao.text:0040C190                                         ; sub_40C796+30o.text:0040C190.text:0040C190 x               = dword ptr -80h.text:0040C190 y               = dword ptr -7Ch.text:0040C190 var_78          = dword ptr -78h.text:0040C190 var_74          = dword ptr -74h.text:0040C190 var_70          = dword ptr -70h.text:0040C190 var_6C          = dword ptr -6Ch.text:0040C190 var_68          = dword ptr -68h.text:0040C190 ho              = dword ptr -64h.text:0040C190 rc              = RECT ptr -60h.text:0040C190 var_50          = dword ptr -50h.text:0040C190 var_4C          = dword ptr -4Ch.text:0040C190 var_46          = byte ptr -46h.text:0040C190 var_45          = byte ptr -45h.text:0040C190 Paint           = tagPAINTSTRUCT ptr -44h.text:0040C190 var_4           = dword ptr -4.text:0040C190 hWnd            = dword ptr  8.text:0040C190 Msg             = dword ptr  0Ch.text:0040C190 wParam          = dword ptr  10h.text:0040C190 lParam          = dword ptr  14h.text:0040C190.text:0040C190                 push    ebp.text:0040C191                 mov     ebp, esp.text:0040C193                 sub     esp, 80h.text:0040C199                 mov     eax, dword_431EAC.text:0040C19E                 xor     eax, ebp.text:0040C1A0                 mov     [ebp+var_4], eax.text:0040C1A3                 mov     eax, [ebp+hWnd].text:0040C1A6                 push    ebx.text:0040C1A7                 push    esi.text:0040C1A8                 mov     esi, [ebp+lParam].text:0040C1AB                 push    edi.text:0040C1AC                 push    0FFFFFFEBh      ; nIndex.text:0040C1AE                 push    eax             ; hWnd.text:0040C1AF                 mov     [ebp+var_4C], eax.text:0040C1B2                 call    ds:GetWindowLongW.text:0040C1B8                 mov     edi, [ebp+Msg].text:0040C1BB                 mov     ebx, eax.text:0040C1BD                 mov     [ebp+var_46], 0.text:0040C1C1                 cmp     edi, 0C000h.text:0040C1C7                 jnb     short loc_40C1E6.text:0040C1C9                 cmp     edi, 400h.text:0040C1CF                 jb      short loc_40C205.text:0040C1D1                 test    ebx, ebx.text:0040C1D3                 jz      short loc_40C1E6.text:0040C1D5                 mov     eax, [ebx].text:0040C1D7                 push    esi.text:0040C1D8                 lea     ecx, [edi-400h].text:0040C1DE                 push    ecx.text:0040C1DF                 push    [ebp+wParam].text:0040C1E2                 mov     ecx, ebx.text:0040C1E4                 call    dword ptr [eax].text:0040C1E6.text:0040C1E6 loc_40C1E6:                             ; CODE XREF: PrevWndFunc+37j.text:0040C1E6                                         ; PrevWndFunc+43j ....text:0040C1E6                 push    esi             ; lParam

由

.text:0040C1D7                 push    esi.text:0040C1D8                 lea     ecx, [edi-400h].text:0040C1DE                 push    ecx.text:0040C1DF                 push    [ebp+wParam].text:0040C1E2                 mov     ecx, ebx.text:0040C1E4                 call    dword ptr [eax]

和

.text:0040C1A7                 push    esi.text:0040C1A8                 mov     esi, [ebp+lParam]

可知，00409db5所在函数的第三个參数是由PrevWndFunc的第四个參数提供。查看一下第四个參数

0:000> dd 0012fcd0 L 80012fcd0  0012fcfc 77d18734 00010652 000004640012fce0  00000001 00000000 0040c190 dcbaabcd

而PrevWndFunc是由User32来调用，第四个參数0值的传入是无法避免。也就是说。00409db5所在的函数，要对第三个參数0值推断。