coders/pcd.c DecodeImage()function potential memory-leak bug

[fisher2020]

Prerequisites

• I have written a descriptive issue title
• I have verified that I am using the latest version of ImageMagick
• I have searched open and closed issues to ensure it has not already been reported

Description

a potential memory leak bug locates in coders/pcd.c

Steps to Reproduce

the bug locates in
https://github.com/ImageMagick/ImageMagick/blob/master/coders/pcd.c : DecodeImage() function.
the code frament is as follows: we allocate buffer memory, we freed it in normal branch，but forgot free it in exception branch

https://github.com/ImageMagick/ImageMagick/blob/master/coders/pcd.c#L186

  buffer=(unsigned char *) AcquireQuantumMemory(0x800,sizeof(*buffer));
  if (buffer == (unsigned char *) NULL)
    ThrowBinaryException(ResourceLimitError,"MemoryAllocationFailed",
      image->filename);

but we forget free it in
https://github.com/ImageMagick/ImageMagick/blob/master/coders/pcd.c#L286

          default:
          {
            ThrowBinaryException(CorruptImageError,"CorruptImage",
              image->filename);
          }

credit: www.vackbot.com ( 墨云科技)

System Configuration

[urban-warrior]

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 @ http://www.imagemagick.org/download/beta/ by sometime tomorrow.

[nohmask]

This was assigned CVE-2018-14435.