我有一个我反编译并想要重写的函数。
这种变化似乎很简单 - 我需要互相替换两大部分代码。在C语言中，它只需要剪切和粘贴。但是在ASM中我遇到了一些困难。尽管跳转指令中的地址是相对的（我已经弄清楚了），但修改后的DLL仍然崩溃，而IDA Pro无法解释新代码。我必须在背景中丢失一些东西。请帮我完成任务，因为我是新手。
以下是列表：
push ebp
mov ebp, esp
sub esp, 20h
mov eax, dword ptr _NDFAPI_NULL_THUNK_DATA_DLA-5D1331CCh
xor eax, ebp
mov [ebp+var_4], eax
push ebx
push esi
push edi
---------------------------------------------
push 398Eh ; string_id
push 0C3BEh ; command_id
mov ecx, esi ; this
call ?AddItemWithStringId@SimpleMenuModel@ui@@QAEXHH@Z ;
ui::SimpleMenuModel::AddItemWithStringId(int,int)
push 3990h ; string_id
push 0C3C0h ; command_id
mov ecx, esi ; this
call ?AddItemWithStringId@SimpleMenuModel@ui@@QAEXHH@Z ;
ui::SimpleMenuModel::AddItemWithStringId(int,int)
push 398Fh ; string_id
push 0C3BFh ; command_id
mov ecx, esi ; this
call ?AddItemWithStringId@SimpleMenuModel@ui@@QAEXHH@Z ;
ui::SimpleMenuModel::AddItemWithStringId(int,int)
---------------------------------------------
mov ebx, ecx
call ?chrome_proxy_header@data_reduction_proxy@@YAPBDXZ ;
data_reduction_proxy::chrome_proxy_header(void)
push eax ; _Ptr
lea ecx, [ebp+_Keyval] ; this
call ??0?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@QAE@PBD@Z
;
std::basic_string<char,std::char_traits<char>,std::allocator<char>>::basic_string<char,std::char_traits<char>,st
d::allocator<char>>(char const *)
lea eax, [ebp+_Keyval]
push eax ; _Keyval
lea eax, [ebp+result]
lea edi, [ebx+3ECh]
push eax ; result
mov ecx, edi ; this
call ?find@?$_Tree@V?$_Tmap_traits@V?$basic_string@DU?$char_traits@D@std@@V?
$allocator@D@2@@std@@V12@U?$less@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@V?
$allocator@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@@std@@@2@
$0A@@std@@@std@@QAE?AV?$_Tree_iterator@V?$_Tree_val@U?$_Tree_simple_types@U?$pair@$$CBV?$basic_string@DU?
$char_traits@D@std@@V?$allocator@D@2@@std@@V12@@std@@@std@@@std@@@2@ABV?$basic_string@DU?$char_traits@D@std@@V?
$allocator@D@2@@2@@Z ;
std::_Tree<std::_Tmap_traits<std::basic_string<char,std::char_traits<char>,std::allocator<char>>,std::basic_stri
ng<char,std::char_traits<char>,std::allocator<char>>,std::less<std::basic_string<char,std::char_traits<char>,std
::allocator<char>>>,std::allocator<std::pair<std::basic_string<char,std::char_traits<char>,std::allocator<char>>
const,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>>,0>>::find
(std::basic_string<char,std::char_traits<char>,std::allocator<char>> const &)
push 0 ; _Newsize
push 1 ; _Built
lea ecx, [ebp+_Keyval] ; this
mov esi, [eax]
call ?_Tidy@?$basic_string@DU?$char_traits@D@std@@V?
$allocator@D@2@@std@@QAEX_NI@Z ; std::basic_string<char,std::char_traits<char>,std::allocator<char>>::_Tidy
(bool,uint)
cmp esi, [edi]
jz short loc_6025D46B
call ?chrome_proxy_lo_fi_directive@data_reduction_proxy@@YAPBDXZ ;
data_reduction_proxy::chrome_proxy_lo_fi_directive(void)
push eax ; _Ptr
lea ecx, [esi+28h] ; this
call ?compare@?$basic_string@DU?$char_traits@D@std@@V?
$allocator@D@2@@std@@QBEHPBD@Z ; std::basic_string<char,std::char_traits<char>,std::allocator<char>>::compare
(char const *)
test eax, eax
jnz short loc_6025D46B
push 3993h ; string_id
push 0C3C4h ; command_id
lea ecx, [ebx+400h] ; this
call ?AddItemWithStringId@SimpleMenuModel@ui@@QAEXHH@Z ;
ui::SimpleMenuModel::AddItemWithStringId(int,int)
.text:6025D46B: ; CODE XREF: RenderViewContextMenu::AppendImageItems
(void)
.text:6025D46B ; RenderViewContextMenu::AppendImageItems(void)
push dword ptr [ebx+3FCh] ; context
call ?
GetForBrowserContext@DataReductionProxyChromeSettingsFactory@@SAPAVDataReductionProxyChromeSettings@@PAVBrowserC
ontext@content@@@Z ; DataReductionProxyChromeSettingsFactory::GetForBrowserContext(content::BrowserContext *)
pop ecx
test eax, eax
jz short loc_6025D499
lea ecx, [ebx+0F4h]
push ecx ; url
mov ecx, eax ; this
call ?CanUseDataReductionProxy@DataReductionProxySettings@data_reduction_proxy@@QBE_NABVGURL@@@Z ;
data_reduction_proxy::DataReductionProxySettings::CanUseDataReductionProxy(GURL const &)
test al, al
jz short loc_6025D499
push 3992h
push 0C3C3h
jmp short loc_6025D4A3
.text:6025D499 ; RenderViewContextMenu::AppendImageItems(void)
push 3991h ; string_id
push 0C3C1h ; command_id
.text:6025D4A3 loc_6025D4A3: ; CODE XREF: RenderViewContextMenu::AppendImageItems(void)
lea esi, [ebx+400h]
mov ecx, esi ; this
call ?AddItemWithStringId@SimpleMenuModel@ui@@QAEXHH@Z ;
ui::SimpleMenuModel::AddItemWithStringId(int,int)
---------------------------------------------------------------------------
mov ecx, [ebp+var_4]
pop edi
pop esi
xor ecx, ebp ; cookie
pop ebx
call @__security_check_cookie@4 ; __security_check_cookie(x)
mov esp, ebp
pop ebp
retn
我所做的是将程序段末尾的虚线移动到它的开头。我有什么冲动？
答案 0 :(得分：2)
移动代码块后的第一行是：
mov ebx, ecx
这会将this中的ecx参数复制到一个不会被第一个函数调用破坏的寄存器中。您需要将此行移到新代码块上方。在整个函数中保持ebx的这个值。
在此之后，您需要
行 lea esi, [ebx+400h]