Fix issue #79

exif.c

@@ -1233,6 +1233,19 @@ void create_EXIF(void)
     }
 }
 
+//--------------------------------------------------------------------------
+// Check the range of the memory block pointed by ptr contains OrientationPtr or not.
+// Return 1 if contains at least one OrientationPtr
+//--------------------------------------------------------------------------
+
+int CheckOrientationPtrs(unsigned char * ptr, unsigned int range){
+    if((OrientationPtr[0] >= (void *)ptr) && (OrientationPtr[0] < (void *)ptr+range))
+        return 1;
+    if((OrientationPtr[1] >= (void *)ptr) && (OrientationPtr[1] < (void *)ptr+range))
+        return 1;
+    return 0;
+}
+
 //--------------------------------------------------------------------------
 // Clear the rotation tag in the exif header to 1.
 // Returns NULL if no orientation tag exists.

jhead.h

@@ -166,6 +166,7 @@ void Clear_EXIF();
 int process_EXIF (unsigned char * CharBuf, int length);
 void ShowImageInfo(int ShowFileInfo);
 void ShowConciseImageInfo(void);
+int CheckOrientationPtrs(unsigned char * ptr, unsigned int range);
 const char * ClearOrientation(void);
 void PrintFormatNumber(void * ValuePtr, int Format, int ByteCount);
 double ConvertAnyFormat(void * ValuePtr, int Format);

jpgfile.c

@@ -483,7 +483,9 @@ int ReplaceThumbnail(const char * ThumbFileName)
              return FALSE;
         }
 
-        ThumbLen = 0;
+        ThumbLen = 0;
+
+
         ThumbnailFile = NULL;
     }
 
@@ -538,7 +540,7 @@ void DiscardAllButExif(void)
             CommentKeeper = Sections[a];
         }else if (Sections[a].Type == M_IPTC && IptcKeeper.Type == 0){
             IptcKeeper = Sections[a];
-        }else{
+        }else if (CheckOrientationPtrs(Sections[a].Data, Sections[a].Size+20) == 0){
             free(Sections[a].Data);
         }
     }