memory leak in WriteGIFImage

[bestshow]

Here is the critical code : (in WriteGIFImage)

  global_colormap=(unsigned char *) AcquireQuantumMemory(768UL,            //1560
    sizeof(*global_colormap));
  colormap=(unsigned char *) AcquireQuantumMemory(768UL,sizeof(*colormap));
  if ((global_colormap == (unsigned char *) NULL) ||
      (colormap == (unsigned char *) NULL))
    ThrowWriterException(ResourceLimitError,"MemoryAllocationFailed");       //1565

AcquireQuantumMemory(…) may return NULL,if one of the “global_colormap” and ”colormap” is NULL，and the other is not，this may cause memory leak error in “If statement”.

[mikayla-grace]

Thanks for the problem report. We can reproduce it and will have a patch to fix it in GIT master branch @ https://github.com/ImageMagick/ImageMagick later today. The patch will be available in the beta releases of ImageMagick @ https://www.imagemagick.org/download/beta/ by sometime tomorrow.

[nohmask]

This was assigned CVE-2017-18254.