#599 heap_buffer_overflow_WRITE in function WriteXWDImage of coders/xwd.c

[galycannon]

There is a heap buffer overflow in function WriteXWDImage of coders/xwd.c whick can be reproduced as below.

=================================================================
==79777==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f669c371b18 at pc 0x00000087f9ea bp 0x7ffe593e7730 sp 0x7ffe593e7720
WRITE of size 1 at 0x7f669c371b18 thread T0
    #0 0x87f9e9 in WriteXWDImage coders/xwd.c:894
    #1 0x47a390 in WriteImage magick/constitute.c:2245
    #2 0x47acf8 in WriteImages magick/constitute.c:2404
    #3 0x42becd in ConvertImageCommand magick/command.c:6101
    #4 0x436a5e in MagickCommand magick/command.c:8886
    #5 0x45f205 in GMCommandSingle magick/command.c:17416
    #6 0x45f451 in GMCommand magick/command.c:17469
    #7 0x40cbc5 in main utilities/gm.c:61
    #8 0x7f6741cd382f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #9 0x40cad8 in _start (/home/test/temp/graphicsmagick-code/utilities/gm+0x40cad8)

0x7f669c371b18 is located 0 bytes to the right of 268436248-byte region [0x7f668c371800,0x7f669c371b18)
allocated by thread T0 here:
    #0 0x7f6744a60602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
    #1 0x4de2d4 in MagickMalloc magick/memory.c:173
    #2 0x87f588 in WriteXWDImage coders/xwd.c:865
    #3 0x47a390 in WriteImage magick/constitute.c:2245
    #4 0x47acf8 in WriteImages magick/constitute.c:2404
    #5 0x42becd in ConvertImageCommand magick/command.c:6101
    #6 0x436a5e in MagickCommand magick/command.c:8886
    #7 0x45f205 in GMCommandSingle magick/command.c:17416
    #8 0x45f451 in GMCommand magick/command.c:17469
    #9 0x40cbc5 in main utilities/gm.c:61
    #10 0x7f6741cd382f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)

SUMMARY: AddressSanitizer: heap-buffer-overflow coders/xwd.c:894 WriteXWDImage
Shadow bytes around the buggy address:
  0x0fed53866310: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0fed53866320: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0fed53866330: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0fed53866340: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0fed53866350: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0fed53866360: 00 00 00[fa]fa fa fa fa fa fa fa fa fa fa fa fa
  0x0fed53866370: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0fed53866380: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0fed53866390: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0fed538663a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0fed538663b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
==79777==ABORTING

System Configuration:

Distributor ID: Ubuntu
Description:    Ubuntu 16.04.2 LTS
Release:    16.04
Codename:   xenial

GraphicsMagick version:

GraphicsMagick 1.4 snapshot-20190322 Q8 http://www.GraphicsMagick.org/
Copyright (C) 2002-2019 GraphicsMagick Group.
Additional copyrights and licenses apply to this software.
See http://www.GraphicsMagick.org/www/Copyright.html for details.

Feature Support:
  Native Thread Safe       yes
  Large Files (> 32 bit)   yes
  Large Memory (> 32 bit)  yes
  BZIP                     yes
  DPS                      no
  FlashPix                 no
  FreeType                 yes
  Ghostscript (Library)    no
  JBIG                     yes
  JPEG-2000                yes
  JPEG                     yes
  Little CMS               yes
  Loadable Modules         no
  Solaris mtmalloc         no
  OpenMP                   yes (201307)
  PNG                      yes
  TIFF                     yes
  TRIO                     no
  Solaris umem             no
  WebP                     yes
  WMF                      yes
  X11                      yes
  XML                      yes
  ZLIB                     yes

Host type: x86_64-pc-linux-gnu

Configured using the command:
  ./configure  'CFLAGS=-g -fsanitize=address' '--enable-shared=no'

Final Build Parameters:
  CC       = gcc
  CFLAGS   = -fopenmp -g -fsanitize=address -Wall -pthread
  CPPFLAGS = -I/usr/include/freetype2 -I/usr/include/libxml2
  CXX      = g++
  CXXFLAGS = -pthread
  LDFLAGS  = 
  LIBS     = -ljbig -lwebp -lwebpmux -llcms2 -ltiff -lfreetype -ljasper -ljpeg -lpng12 -lwmflite -lXext -lSM -lICE -lX11 -llzma -lbz2 -lxml2 -lz -lm -lpthread

[Bob Friesenhahn]

This problem (and more) is fixed by Mercurial changeset 15953:d823d23a474b. Thanks for the report.