[fpc-devel] Address of procedures in linked libs

Andrew Haines AndrewD207 at aol.com
Wed May 7 03:13:16 CEST 2008


In a dynamically linked in library (not dlload) if I do
@SomeProcInSharedObject is it giving me the address of the code in
memory or something else?

For instance I tried to overwrite a proc in gtk like so:

Orig_addr := PtrUInt(@gtk_widget_get_name);
New_addr := PtrUInt(@glue_gtk_widget_get_name);
New_Size := ProcSize(New_addr, PtrUint(@nothing));

DumpMemory(Pointer(Orig_addr), 32);
DumpMemory(Pointer(New_addr), 32);

Move(Pointer(New_addr)^, Pointer(Orig_addr)^, New_Size);

The Output was this:

Memory at Orig_addr:
8B8225FF E9000000 8B7A25FF E9000000
Memory of New_addr:
E5894855 F87D8948 FFFFCBE8 458B48F0

the memory pointed to at Orig_addr looks bogus to me. Is it a table

The Move command causes an error.

This is in linux/64 bit.



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