Commit message: ...
CVE: CVE-2018-14551
CWE: CWE-787
Vulnerability description: The ReadMATImageV4 function in coders/mat.c in ImageMagick 7.0.8-7 uses an uninitialized variable, leading to memory corruption.

Project: ImageMagick6
File: mat.c

static Image *ReadMATImageV4(const ImageInfo *image_info,Image *image,
  ExceptionInfo *exception)
{
  typedef struct {
    unsigned char Type[4];
    unsigned int nRows;
    unsigned int nCols;
    unsigned int imagf;
    unsigned int nameLen;
  } MAT4_HDR;

  long
    ldblk;

  EndianType
    endian;

  Image
    *rotate_image;

  MagickBooleanType
    status;

  MAT4_HDR
    HDR;

  QuantumInfo
    *quantum_info;

  QuantumFormatType
    format_type;

  register ssize_t
    i;

  ssize_t
    y;

  unsigned char
    *pixels;

  unsigned int
    depth;

  (void) SeekBlob(image,0,SEEK_SET);
  ldblk=ReadBlobLSBLong(image);
  if ((ldblk > 9999) || (ldblk < 0))
    return((Image *) NULL);
  HDR.Type[3]=ldblk % 10; ldblk /= 10;  /* T digit */
  HDR.Type[2]=ldblk % 10; ldblk /= 10;  /* P digit */
  HDR.Type[1]=ldblk % 10; ldblk /= 10;  /* O digit */
  HDR.Type[0]=ldblk;        /* M digit */
  if (HDR.Type[3] != 0) return((Image *) NULL);    /* Data format */
  if (HDR.Type[2] != 0) return((Image *) NULL);    /* Always 0 */
  if (HDR.Type[0] == 0)
    {
      HDR.nRows=ReadBlobLSBLong(image);
      HDR.nCols=ReadBlobLSBLong(image);
      HDR.imagf=ReadBlobLSBLong(image);
      HDR.nameLen=ReadBlobLSBLong(image);
      endian=LSBEndian;
    }
  else
    {
      HDR.nRows=ReadBlobMSBLong(image);
      HDR.nCols=ReadBlobMSBLong(image);
      HDR.imagf=ReadBlobMSBLong(image);
      HDR.nameLen=ReadBlobMSBLong(image);
      endian=MSBEndian;
    }
  if (HDR.nameLen > 0xFFFF)
    return((Image *) NULL);
  for (i=0; i < (ssize_t) HDR.nameLen; i++)
  {
    int
      byte;

    /*
      Skip matrix name.
    */
    byte=ReadBlobByte(image);
    if (byte == EOF)
      return((Image *) NULL);
  }
  image->columns=(size_t) HDR.nRows;
  image->rows=(size_t) HDR.nCols;
  SetImageColorspace(image,GRAYColorspace);
  if (image_info->ping != MagickFalse)
    {
      Swap(image->columns,image->rows);
      return(image);
    }
  status=SetImageExtent(image,image->columns,image->rows);
  if (status == MagickFalse)
    return((Image *) NULL);
  quantum_info=AcquireQuantumInfo(image_info,image);
  if (quantum_info == (QuantumInfo *) NULL)
    return((Image *) NULL);
  switch(HDR.Type[1])
  {
    case 0:
      format_type=FloatingPointQuantumFormat;
      depth=64;
      break;
    case 1:
      format_type=FloatingPointQuantumFormat;
      depth=32;
      break;
    case 2:
      format_type=UnsignedQuantumFormat;
      depth=16;
      break;
    case 3:
      format_type=SignedQuantumFormat;
      depth=16;
    case 4:
      format_type=UnsignedQuantumFormat;
      depth=8;
      break;
    default:
      format_type=UnsignedQuantumFormat;
      depth=8;
      break;
  }
  image->depth=depth;
  if (HDR.Type[0] != 0)
    SetQuantumEndian(image,quantum_info,MSBEndian);
  status=SetQuantumFormat(image,quantum_info,format_type);
  status=SetQuantumDepth(image,quantum_info,depth);
  status=SetQuantumEndian(image,quantum_info,endian);
  SetQuantumScale(quantum_info,1.0);
  pixels=(unsigned char *) GetQuantumPixels(quantum_info);
  for (y=0; y < (ssize_t) image->rows; y++)
  {
    int
      status;

    register PixelPacket
      *magick_restrict q;

    status=ReadBlob(image,depth/8*image->columns,(unsigned char *) pixels);
    if (status == -1)
      break;
    q=QueueAuthenticPixels(image,0,image->rows-y-1,image->columns,1,exception);
    if (q == (PixelPacket *) NULL)
      break;
    (void) ImportQuantumPixels(image,(CacheView *) NULL,quantum_info,
      GrayQuantum,pixels,exception);
    if ((HDR.Type[1] == 2) || (HDR.Type[1] == 3))
      FixSignedValues(q,image->columns);
    if (SyncAuthenticPixels(image,exception) == MagickFalse)
      break;
    if (image->previous == (Image *) NULL)
      {
        status=SetImageProgress(image,LoadImageTag,(MagickOffsetType) y,
          image->rows);
        if (status == MagickFalse)
          break;
      }
  }
  if (HDR.imagf == 1)
    for (y=0; y < (ssize_t) image->rows; y++)
    {
      /*
        Read complex pixels.
      */
      status=ReadBlob(image,depth/8*image->columns,(unsigned char *) pixels);
      if (status == -1)
        break;
      if (HDR.Type[1] == 0)
        InsertComplexDoubleRow((double *) pixels,y,image,0,0);
      else
        InsertComplexFloatRow((float *) pixels,y,image,0,0);
    }
  quantum_info=DestroyQuantumInfo(quantum_info);
  rotate_image=RotateImage(image,90.0,exception);
  if (rotate_image != (Image *) NULL)
    {
      image=DestroyImage(image);
      image=rotate_image;
    }
  return(image);
}