Why execution of a portion of code loaded from external file is not halted by the OS?
- by menjaraz
I've harnessed a project released on internet a long time ago. Here comes the details, all irrelevant things being stripped off for sake of concision and clarity.
A binary file whose content is descibed below
HEX DUMP:
55 89 E5 83 EC 08 C7 45 FC 00 00 00 00 8B 45 FC
3B 45 10 72 02 EB 19 8B 45 FC 8B 55 0C 01 C2 8B
45 FC 03 45 08 8A 00 88 02 8D 45 FC FF 00 EB DD
C6 45 FA 00 83 7D 10 01 76 6C 80 7D FA 00 74 02
EB 64 C6 45 FA 01 C7 45 FC 00 00 00 00 8B 45 10
48 39 45 FC 72 02 EB E2 8B 45 FC 8B 4D 0C 01 C1
8B 45 FC 03 45 0C 8D 50 01 8A 01 3A 02 73 30 8B
45 FC 03 45 0C 8A 00 88 45 FB 8B 45 FC 8B 55 0C
01 C2 8B 45 FC 03 45 0C 40 8A 00 88 02 8B 45 FC
03 45 0C 8D 50 01 8A 45 FB 88 02 C6 45 FA 00 8D
45 FC FF 00 EB A7 C9 C2 0C 00 90 90 90 90 90 90
is loaded into memory and executed using the following method snippet
var
MySrcArray,
MyDestArray: array [1 .. 15] of Byte;
// ...
MyBuffer: Pointer;
TheProc: procedure;
SortIt: procedure(ASrc, ADest: Pointer; ASize: LongWord); stdcall;
begin
// Initialization of MySrcArray with random Bytes and display here ...
// Instructions of loading of the binary file into MyBuffer using merely **GetMem** here ...
@SortIt := MyBuffer;
try
SortIt(@MySrcArray, @MyDestArray, 15);
// Display of MyDestArray (The outcome of the processing !)
except
// Invalid code error handling
end;
// Cleaning code here ...
end;
works like a charm on my box.
My Question:
How comes it works without using VirtualAlloc and/or VirtualProtect?
