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Kazyaka



Joined: 10 Oct 2011
Posts: 62
Location: Earth
Kazyaka 18 Jul 2012, 12:22
I've this code:
Code:
 ;  
 ;      manual PE  
 ;  
        image_base      equ 0x400000
        alignment       equ 0x4  
        stack_reserve   equ 0x1000  
        stack_commit    equ 0x1000  
        heap_reserve    equ 0x1000  
        heap_commit     equ 0x1000  
 ;  
 ;      dos header  
 ;      pe header  
 ;      optional header  
 ;      directory entries  
 ;      import header  
 ;      code directory  
 ;      import directory  
 ;

 format binary as "exe" 
        use32  
          
        dos_header:  
          
                dw 'MZ'                 ; DOS signature  
                db 0x3A dup(0)          ; unused  
                dd 0x40                 ; PE header address  
          
        pe_header:  
          
                db 'PE',0,0             ; PE signature  
                dw 0x014C               ; cpu (386)  
                dw 1                    ; number of sections  
                dd 0                    ; timestamp  
                dd 0                    ; symbol table address  
                dd 0                    ; number of symbols  
                dw sizeof.header        ; size of optional header  
                dw 0x010F               ; characteristics  
                  
        optional_header:  
                  
                dw 0x010B               ; magic  
                dw 0                    ; linker version  
                dd 0                    ; size of code section  
                dd 0                    ; size of initialised data  
                dd 0                    ; size of uninitialise data  
                dd code_directory       ; entry point address  
                dd 0                    ; base of code  
                dd 0                    ; base of data  
                dd image_base           ; base of image  
                dd alignment            ; section alignment  
                dd alignment            ; file alignment  
                dw 0                    ; os version major  
                dw 0                    ; os version minor  
                dw 0                    ; image version major  
                dw 0                    ; image version minor  
                dw 4                    ; subsystem version major  
                dw 0                    ; subsystem version minor  
                dd 0                    ; win32 version (reserved)  
                dd sizeof.image         ; image size  
                dd code_directory       ; header size  
                dd 0                    ; checksum  
                dw 0x0002               ; subsystem (GUI)  
                dw 0                    ; dll characteristics  
                dd stack_reserve        ; stack reserve size  
                dd stack_commit         ; stack commit size  
                dd heap_reserve         ; heap reserve size  
                dd heap_commit          ; heap commit size  
                dd 0                    ; loader flags (obsolete)  
                dd 16                   ; number of directory entries  
                  
        directory_entries:  
                  
                dq 0                    ; export  
                dd import_directory     ; import section rva  
                dd sizeof.import        ; import section size  
                dq 14 dup(0)            ; the rest  
                  
        import_header:  
                  
                dq '.import'            ; name  
                dd sizeof.import        ; virtual size  
                dd code_directory       ; rva  
                dd sizeof.import        ; raw size  
                dd code_directory       ; raw pointer to data  
                dd 0                    ; pointer to relocations  
                dd 0                    ; pointer to line numbers  
                dw 0                    ; number of relocations  
                dw 0                    ; number of line numbers  
                dd 0x0E0000020          ; characteristics  
                align alignment 
                  
        code_directory:  

                push 0  
                push title+image_base  
                push message+image_base  
                push 0  
                call[MessageBoxA+image_base]
                push 0
                call[ExitProcess+image_base]
                title: db 'Title',0 
                message: db 'Hello world',0
                  
        import_directory:  

                MessageBoxA dd 0x7E4507EA
                ExitProcess dd 0x7C81CAFA
        file_end:  
                  
                sizeof.import = file_end-import_directory  
                sizeof.header = import_header-optional_header  
                sizeof.image = file_end  
    


and I try to remove image_base from pointers. But when I do it and add org my program crashes:

Code:
        code_directory:  
                org image_base
                push 0  
                push title
                push message
                push 0  
                call[MessageBoxA]
                push 0
                call[ExitProcess]
                title: db 'Title',0 
                message: db 'Hello world',0     


How can I correctly use org in this example?
Post 18 Jul 2012, 12:22
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shutdownall



Joined: 02 Apr 2010
Posts: 517
Location: Munich
shutdownall 19 Jul 2012, 15:41
Please post complete changed code.
Did you adapt your values for
* MessageBoxA
* ExitProcess
?

You could move org to the line directly in front of title:
but have to be aware that ALL following lines will be affected by org.
Post 19 Jul 2012, 15:41
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Kazyaka



Joined: 10 Oct 2011
Posts: 62
Location: Earth
Kazyaka 20 Jul 2012, 11:54
Here is a complete code:
Code:
 ;
 ;      manual PE   
 ;   
        image_base      equ 0x400000 
        alignment       equ 0x4   
        stack_reserve   equ 0x1000   
        stack_commit    equ 0x1000   
        heap_reserve    equ 0x1000   
        heap_commit     equ 0x1000   
 ;   
 ;      dos header   
 ;      pe header   
 ;      optional header   
 ;      directory entries   
 ;      import header   
 ;      code directory   
 ;      import directory   
 ; 

 format binary as "exe"  
        use32   
           
        dos_header:   
           
                dw 'MZ'                 ; DOS signature   
                db 0x3A dup(0)          ; unused   
                dd 0x40                 ; PE header address   
           
        pe_header:   
           
                db 'PE',0,0             ; PE signature   
                dw 0x014C               ; cpu (386)   
                dw 1                    ; number of sections   
                dd 0                    ; timestamp   
                dd 0                    ; symbol table address   
                dd 0                    ; number of symbols   
                dw sizeof.header        ; size of optional header   
                dw 0x010F               ; characteristics   
                   
        optional_header:   
                   
                dw 0x010B               ; magic   
                dw 0                    ; linker version   
                dd 0                    ; size of code section   
                dd 0                    ; size of initialised data   
                dd 0                    ; size of uninitialise data   
                dd code_directory       ; entry point address   
                dd 0                    ; base of code   
                dd 0                    ; base of data   
                dd image_base           ; base of image   
                dd alignment            ; section alignment   
                dd alignment            ; file alignment   
                dw 0                    ; os version major   
                dw 0                    ; os version minor   
                dw 0                    ; image version major   
                dw 0                    ; image version minor   
                dw 4                    ; subsystem version major   
                dw 0                    ; subsystem version minor   
                dd 0                    ; win32 version (reserved)   
                dd sizeof.image         ; image size   
                dd code_directory       ; header size   
                dd 0                    ; checksum   
                dw 0x0002               ; subsystem (GUI)   
                dw 0                    ; dll characteristics   
                dd stack_reserve        ; stack reserve size   
                dd stack_commit         ; stack commit size   
                dd heap_reserve         ; heap reserve size   
                dd heap_commit          ; heap commit size   
                dd 0                    ; loader flags (obsolete)   
                dd 16                   ; number of directory entries   
                   
        directory_entries:   
                   
                dq 0                    ; export   
                dd import_directory     ; import section rva   
                dd sizeof.import        ; import section size   
                dq 14 dup(0)            ; the rest   
                   
        import_header:   
                   
                dq '.import'            ; name   
                dd sizeof.import        ; virtual size   
                dd code_directory       ; rva   
                dd sizeof.import        ; raw size   
                dd code_directory       ; raw pointer to data   
                dd 0                    ; pointer to relocations   
                dd 0                    ; pointer to line numbers   
                dw 0                    ; number of relocations   
                dw 0                    ; number of line numbers   
                dd 0x0E0000020          ; characteristics   
                align alignment  
                   
         code_directory:
                org image_base 
                push 0   
                push title 
                push message 
                push 0   
                call[MessageBoxA] 
                push 0 
                call[ExitProcess] 
                title: db 'Title',0  
                message: db 'Hello world',0
                   
        import_directory:   

                MessageBoxA dd 0x7E4507EA 
                ExitProcess dd 0x7C81CAFA 
        file_end:   
                   
                sizeof.import = file_end-import_directory   
                sizeof.header = import_header-optional_header   
                sizeof.image = file_end    

And here is a problem because org changes all lines in code.
Post 20 Jul 2012, 11:54
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shutdownall



Joined: 02 Apr 2010
Posts: 517
Location: Munich
shutdownall 20 Jul 2012, 15:15
file_end changes after org and sizeof.image is calculated wrong.

You could do correct it's calculation by:

sizeof.image = file_end-image_base+code_directory-doc_header

Anyway I am not sure why you want to use org in this context.
To use "...+image_base" is the better alternative I think.

Anyway it is calculated during compile not in runtime.
So there is no disadvantage about the add.
Post 20 Jul 2012, 15:15
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baldr



Joined: 19 Mar 2008
Posts: 1651
baldr 26 Jul 2012, 20:26
Kazyaka,

Import directory entry should point to somewhat different structure than simple list of some constants. You may consult PE/COFF specification for further directions. Another option is to resort to ready-made hand-written PEs that are abundant here and there.

P.S. Moderators, this thread has nothing to do with macros.
Post 26 Jul 2012, 20:26
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