granicus.if.org Git - imagemagick/blob - coders/stegano.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   6 %              SSSSS  TTTTT  EEEEE   GGGG   AAA   N   N   OOO                 %
   7 %              SS       T    E      G      A   A  NN  N  O   O                %
   8 %               SSS     T    EEE    G  GG  AAAAA  N N N  O   O                %
   9 %                 SS    T    E      G   G  A   A  N  NN  O   O                %
  10 %              SSSSS    T    EEEEE   GGG   A   A  N   N   OOO                 %
  11 %                                                                             %
  12 %                                                                             %
  13 %                       Write A Steganographic Image.                         %
  14 %                                                                             %
  15 %                              Software Design                                %
  16 %                                   Cristy                                    %
  17 %                                 July 1992                                   %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2017 ImageMagick Studio LLC, a non-profit organization      %
  21 %  dedicated to making software imaging solutions freely available.           %
  22 %                                                                             %
  23 %  You may not use this file except in compliance with the License.  You may  %
  24 %  obtain a copy of the License at                                            %
  25 %                                                                             %
  26 %    https://www.imagemagick.org/script/license.php                           %
  27 %                                                                             %
  28 %  Unless required by applicable law or agreed to in writing, software        %
  29 %  distributed under the License is distributed on an "AS IS" BASIS,          %
  30 %  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
  31 %  See the License for the specific language governing permissions and        %
  32 %  limitations under the License.                                             %
  33 %                                                                             %
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35 %
  36 %
  37 */
  38 \f
  39 /*
  40   Include declarations.
  41 */
  42 #include "MagickCore/studio.h"
  43 #include "MagickCore/blob.h"
  44 #include "MagickCore/blob-private.h"
  45 #include "MagickCore/cache.h"
  46 #include "MagickCore/colormap.h"
  47 #include "MagickCore/constitute.h"
  48 #include "MagickCore/exception.h"
  49 #include "MagickCore/exception-private.h"
  50 #include "MagickCore/image.h"
  51 #include "MagickCore/image-private.h"
  52 #include "MagickCore/list.h"
  53 #include "MagickCore/magick.h"
  54 #include "MagickCore/memory_.h"
  55 #include "MagickCore/monitor.h"
  56 #include "MagickCore/monitor-private.h"
  57 #include "MagickCore/pixel-accessor.h"
  58 #include "MagickCore/quantum-private.h"
  59 #include "MagickCore/static.h"
  60 #include "MagickCore/string_.h"
  61 #include "MagickCore/module.h"
  62 \f
  63 /*
  64 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  65 %                                                                             %
  66 %                                                                             %
  67 %                                                                             %
  68 %   R e a d S T E G A N O I m a g e                                           %
  69 %                                                                             %
  70 %                                                                             %
  71 %                                                                             %
  72 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  73 %
  74 %  ReadSTEGANOImage() reads a steganographic image hidden within another
  75 %  image type.  It allocates the memory necessary for the new Image structure
  76 %  and returns a pointer to the new image.
  77 %
  78 %  The format of the ReadSTEGANOImage method is:
  79 %
  80 %      Image *ReadSTEGANOImage(const ImageInfo *image_info,
  81 %        ExceptionInfo *exception)
  82 %
  83 %  A description of each parameter follows:
  84 %
  85 %    o image_info: the image info.
  86 %
  87 %    o exception: return any errors or warnings in this structure.
  88 %
  89 */
  90 static Image *ReadSTEGANOImage(const ImageInfo *image_info,
  91   ExceptionInfo *exception)
  92 {
  93 #define GetBit(alpha,i) (((size_t) (alpha) >> (size_t) (i)) & 0x01)
  94 #define SetBit(i,set) SetPixelIndex(image,(Quantum) ((set) != 0 ? \
  95   (size_t) GetPixelIndex(image,q) | (one << (size_t) (i)) : \
  96   (size_t) GetPixelIndex(image,q) & ~(one << (size_t) (i))),q)
  97
  98   Image
  99     *image,
 100     *watermark;
 101
 102   ImageInfo
 103     *read_info;
 104
 105   int
 106     c;
 107
 108   MagickBooleanType
 109     status;
 110
 111   PixelInfo
 112     pixel;
 113
 114   register Quantum
 115     *q;
 116
 117   register ssize_t
 118     x;
 119
 120   size_t
 121     depth,
 122     one;
 123
 124   ssize_t
 125     i,
 126     j,
 127     k,
 128     y;
 129
 130   /*
 131     Initialize Image structure.
 132   */
 133   assert(image_info != (const ImageInfo *) NULL);
 134   assert(image_info->signature == MagickCoreSignature);
 135   if (image_info->debug != MagickFalse)
 136     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",
 137       image_info->filename);
 138   assert(exception != (ExceptionInfo *) NULL);
 139   assert(exception->signature == MagickCoreSignature);
 140   one=1;
 141   image=AcquireImage(image_info,exception);
 142   if ((image->columns == 0) || (image->rows == 0))
 143     ThrowReaderException(OptionError,"MustSpecifyImageSize");
 144   read_info=CloneImageInfo(image_info);
 145   SetImageInfoBlob(read_info,(void *) NULL,0);
 146   *read_info->magick='\0';
 147   watermark=ReadImage(read_info,exception);
 148   read_info=DestroyImageInfo(read_info);
 149   if (watermark == (Image *) NULL)
 150     return((Image *) NULL);
 151   watermark->depth=MAGICKCORE_QUANTUM_DEPTH;
 152   if (AcquireImageColormap(image,MaxColormapSize,exception) == MagickFalse)
 153     ThrowReaderException(ResourceLimitError,"MemoryAllocationFailed");
 154   if (image_info->ping != MagickFalse)
 155     {
 156       (void) CloseBlob(image);
 157       return(GetFirstImageInList(image));
 158     }
 159   status=SetImageExtent(image,image->columns,image->rows,exception);
 160   if (status == MagickFalse)
 161     return(DestroyImageList(image));
 162   for (y=0; y < (ssize_t) image->rows; y++)
 163   {
 164     q=QueueAuthenticPixels(image,0,y,image->columns,1,exception);
 165     if (q == (Quantum *) NULL)
 166       break;
 167     for (x=0; x < (ssize_t) image->columns; x++)
 168     {
 169       SetPixelIndex(image,0,q);
 170       q+=GetPixelChannels(image);
 171     }
 172     if (SyncAuthenticPixels(image,exception) == MagickFalse)
 173       break;
 174   }
 175   /*
 176     Get hidden watermark from low-order bits of image.
 177   */
 178   c=0;
 179   i=0;
 180   j=0;
 181   i=(ssize_t) (watermark->depth-1);
 182   depth=watermark->depth;
 183   for (k=image->offset; (i >= 0) && (j < (ssize_t) depth); i--)
 184   {
 185     for (y=0; (y < (ssize_t) image->rows) && (j < (ssize_t) depth); y++)
 186     {
 187       x=0;
 188       for ( ; (x < (ssize_t) image->columns) && (j < (ssize_t) depth); x++)
 189       {
 190         if ((k/(ssize_t) watermark->columns) >= (ssize_t) watermark->rows)
 191           break;
 192         (void) GetOneVirtualPixelInfo(watermark,UndefinedVirtualPixelMethod,
 193           k % (ssize_t) watermark->columns,k/(ssize_t) watermark->columns,
 194           &pixel,exception);
 195         q=GetAuthenticPixels(image,x,y,1,1,exception);
 196         if (q == (Quantum *) NULL)
 197           break;
 198         switch (c)
 199         {
 200           case 0:
 201           {
 202             SetBit(i,GetBit(pixel.red,j));
 203             break;
 204           }
 205           case 1:
 206           {
 207             SetBit(i,GetBit(pixel.green,j));
 208             break;
 209           }
 210           case 2:
 211           {
 212             SetBit(i,GetBit(pixel.blue,j));
 213             break;
 214           }
 215         }
 216         if (SyncAuthenticPixels(image,exception) == MagickFalse)
 217           break;
 218         c++;
 219         if (c == 3)
 220           c=0;
 221         k++;
 222         if (k == (ssize_t) (watermark->columns*watermark->columns))
 223           k=0;
 224         if (k == image->offset)
 225           j++;
 226       }
 227     }
 228     status=SetImageProgress(image,LoadImagesTag,(MagickOffsetType) i,depth);
 229     if (status == MagickFalse)
 230       break;
 231   }
 232   watermark=DestroyImage(watermark);
 233   (void) SyncImage(image,exception);
 234   return(GetFirstImageInList(image));
 235 }
 236 \f
 237 /*
 238 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 239 %                                                                             %
 240 %                                                                             %
 241 %                                                                             %
 242 %   R e g i s t e r S T E G A N O I m a g e                                   %
 243 %                                                                             %
 244 %                                                                             %
 245 %                                                                             %
 246 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 247 %
 248 %  RegisterSTEGANOImage() adds attributes for the STEGANO image format to
 249 %  the list of supported formats.  The attributes include the image format
 250 %  tag, a method to read and/or write the format, whether the format
 251 %  supports the saving of more than one frame to the same file or blob,
 252 %  whether the format supports native in-memory I/O, and a brief
 253 %  description of the format.
 254 %
 255 %  The format of the RegisterSTEGANOImage method is:
 256 %
 257 %      size_t RegisterSTEGANOImage(void)
 258 %
 259 */
 260 ModuleExport size_t RegisterSTEGANOImage(void)
 261 {
 262   MagickInfo
 263     *entry;
 264
 265   entry=AcquireMagickInfo("STEGANO","STEGANO","Steganographic image");
 266   entry->decoder=(DecodeImageHandler *) ReadSTEGANOImage;
 267   entry->format_type=ImplicitFormatType;
 268   (void) RegisterMagickInfo(entry);
 269   return(MagickImageCoderSignature);
 270 }
 271 \f
 272 /*
 273 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 274 %                                                                             %
 275 %                                                                             %
 276 %                                                                             %
 277 %   U n r e g i s t e r S T E G A N O I m a g e                               %
 278 %                                                                             %
 279 %                                                                             %
 280 %                                                                             %
 281 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 282 %
 283 %  UnregisterSTEGANOImage() removes format registrations made by the
 284 %  STEGANO module from the list of supported formats.
 285 %
 286 %  The format of the UnregisterSTEGANOImage method is:
 287 %
 288 %      UnregisterSTEGANOImage(void)
 289 %
 290 */
 291 ModuleExport void UnregisterSTEGANOImage(void)
 292 {
 293   (void) UnregisterMagickInfo("STEGANO");
 294 }