zip.asm

; a nasm source to defines a dual ZIP for MD5 collisions

; build with `nasm -o zip.zip zip.asm`

; Ange Albertini 2018


BITS 32
%include "zip.inc"

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; Replace File 1 and 2 values.

; reminder: incbin "<file>", <start>, <size>


; File 1

%macro file1.name 0
  db 'hello.txt'
%endmacro

%macro file1.content 0
%%start:
  db 'Hello World!', 0ah
file1.compsize equ $ - %%start
%endmacro

file1.compression equ COMP_STORED
file1.decsize     equ file1.compsize
file1.CRC32       equ 0x7d14dddd

                                                          ; File 2

                                                          %macro file2.name 0
                                                              db 'bye.txt'
                                                          %endmacro

                                                          %macro file2.content 0
                                                          %%start:
                                                            db 'Bye World!', 0ah
                                                          file2.compsize equ $ - %%start
                                                          %endmacro

                                                          file2.compression equ COMP_STORED
                                                          file2.decsize     equ file2.compsize
                                                          file2.CRC32       equ 0xcedb178e

                                                          ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

                                                          file2:
                                                          istruc filerecord
                                                            at filerecord.frSignature,        db "PK", 3, 4
                                                            at filerecord.frVersion,          dw 0ah
                                                            at filerecord.frCompression,      dw file2.compression
                                                            at filerecord.frCrc,              dd file2.CRC32
                                                            at filerecord.frCompressedSize,   dd file2.compsize
                                                            at filerecord.frUncompressedSize, dd file2.decsize
                                                            at filerecord.frFileNameLength,   dw lfhname2.len
                                                            at filerecord.frExtraFieldLength, dw extra2.len
                                                          iend

                                                          lfhname2:
                                                            file2.name
                                                          lfhname2.len equ $ - lfhname2

                                                          extra2:
                                                            field2:
                                                              .id dw 0
                                                              .len dw extra2.len - 4

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

file1:
istruc filerecord
  at filerecord.frSignature,        db "PK", 3, 4
  at filerecord.frVersion,          dw 0ah
  at filerecord.frCompression,      dw file1.compression
  at filerecord.frCrc,              dd file1.CRC32
  at filerecord.frCompressedSize,   dd file1.compsize
  at filerecord.frUncompressedSize, dd file1.decsize
  at filerecord.frFileNameLength,   dw lfhname1.len
  at filerecord.frExtraFieldLength, dw extra1.len
iend

lfhname1:
  file1.name
lfhname1.len equ $ - lfhname1

extra1:
  field1:
    .id dw 0
    .len dw extra1.len - 4
                                                            extra2.len equ $ - extra2

                                                          data2:
                                                            file2.content
                                                          data2.len equ $ - data2

                                                          ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

                                                          CD2:
                                                            istruc direntry
                                                              at direntry.deSignature,        db "PK", 1, 2
                                                              at direntry.deVersionToExtract, dw 0ah
                                                              at direntry.deCrc,              dd file2.CRC32
                                                              at direntry.deCompressedSize,   dd data2.len
                                                              at direntry.deUncompressedSize, dd data2.len
                                                              at direntry.deFileNameLength,   dw cdname2.len
                                                              at direntry.deFileCommentLength,dw cdcom2.len
                                                              at direntry.deHeaderOffset,     dd file2
                                                            iend

                                                            cdname2:
                                                              file2.name
                                                            .len equ $ - cdname2

                                                            cdcom2:
                                                              db 0 ; truncating
  extra1.len equ $ - extra1

data1:
  file1.content
data1.len equ $ - data1

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

CD1:
  istruc direntry
    at direntry.deSignature,        db "PK", 1, 2
    at direntry.deVersionToExtract, dw 0ah
    at direntry.deCrc,              dd file1.CRC32
    at direntry.deCompressedSize,   dd data1.len
    at direntry.deUncompressedSize, dd data1.len
    at direntry.deFileNameLength,   dw cdname1.len
    at direntry.deFileCommentLength,dw cdcom1.len
    at direntry.deHeaderOffset,     dd file1
  iend
  cdname1:
    file1.name
  cdname1.len equ $ - cdname1

  cdcom1:
    db 0 ; truncating
    align 40h, db 0 ; to align EoCD1 for first collision

  cdcom1.len equ $ - cdcom1

CD1.len equ $ - CD1

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

EoCD1:
istruc endlocator
  at endlocator.elSignature,          db "PK", 5, 0x06
  at endlocator.elEntriesOnDisk,      db 1
  at endlocator.elEntriesInDirectory, db 1
  at endlocator.elDirectorySize,      dd CD1.len
  at endlocator.elDirectoryOffset,    dd CD1
  at endlocator.elCommentLength,      dw EoCD1com.len
iend

EoCD1com:
  db 0 ; truncating

  align 4, db 'M' ; UniColl prefix

  align 40h, db 0 ; end of first collision block
  
  ; second collision block
  db 0
  align 40h, db 0
                                                             cdcom2.len equ $ - cdcom2

                                                           CD2.len equ $ - CD2

                                                           ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

                                                           EoCD2:
                                                           istruc endlocator
                                                             at endlocator.elSignature,          db "PK", 5, 0x86 ; 0x06/0x86 because of UniColl
                                                             at endlocator.elEntriesOnDisk,      db 1
                                                             at endlocator.elEntriesInDirectory, db 1
                                                             at endlocator.elDirectorySize,      dd CD2.len
                                                             at endlocator.elDirectoryOffset,    dd CD2
                                                             at endlocator.elCommentLength,      dw EoCD2com.len
                                                           iend

                                                           EoCD2com:
                                                             db 0 ; truncating
                                                             
                                                             align 4, db 'M' ; Unicoll prefix

                                                             align 40h, db 0 ; end of first collision block
                                                             
                                                             ; second collision block
                                                             db 0
                                                             align 40h, db 0

                                                           EoCD2com.len equ $ - EoCD2com
EoCD1com.len equ $ - EoCD1com