File ImageMagick-CVE-2020-25676.patch of Package ImageMagick.17846

Index: ImageMagick-7.0.7-34/MagickCore/pixel.c
===================================================================
--- ImageMagick-7.0.7-34.orig/MagickCore/pixel.c	2018-05-20 17:55:43.000000000 +0200
+++ ImageMagick-7.0.7-34/MagickCore/pixel.c	2020-12-04 10:56:42.444581323 +0100
@@ -4448,6 +4448,15 @@ static inline void CatromWeights(const d
   (*weights)[2]=x-(*weights)[3]-gamma;
 }
 
+static inline double ConstrainPixelOffset(double x)
+{
+  if (x < (double) -(SSIZE_MAX-512))
+    return((double) -(SSIZE_MAX-512));
+  if (x > (double) (SSIZE_MAX-512))
+    return((double) (SSIZE_MAX-512));
+  return(x);
+}
+
 static inline void SplineWeights(const double x,double (*weights)[4])
 {
   double
@@ -4474,15 +4483,6 @@ static inline double MeshInterpolate(con
   return(delta->x*x+delta->y*y+(1.0-delta->x-delta->y)*p);
 }
 
-/*
-static inline ssize_t NearestNeighbor(const double x)
-{
-  if (x >= 0.0)
-    return((ssize_t) (x+0.5));
-  return((ssize_t) (x-0.5));
-}
-*/
-
 MagickExport MagickBooleanType InterpolatePixelChannel(const Image *image,
   const CacheView_ *image_view,const PixelChannel channel,
   const PixelInterpolateMethod method,const double x,const double y,
@@ -4518,8 +4518,8 @@ MagickExport MagickBooleanType Interpola
   status=MagickTrue;
   *pixel=0.0;
   traits=GetPixelChannelTraits(image,channel);
-  x_offset=(ssize_t) floor(x);
-  y_offset=(ssize_t) floor(y);
+  x_offset=(ssize_t) floor(ConstrainPixelOffset(x));
+  y_offset=(ssize_t) floor(ConstrainPixelOffset(y));
   interpolate=method;
   if (interpolate == UndefinedInterpolatePixel)
     interpolate=image->interpolate;
@@ -4536,8 +4536,8 @@ MagickExport MagickBooleanType Interpola
       if (interpolate == Average9InterpolatePixel)
         {
           count=3;
-          x_offset=(ssize_t) (floor(x+0.5)-1);
-          y_offset=(ssize_t) (floor(y+0.5)-1);
+          x_offset=(ssize_t) (floor(ConstrainPixelOffset(x)+0.5)-1);
+          y_offset=(ssize_t) (floor(ConstrainPixelOffset(y)+0.5)-1);
         }
       else
         if (interpolate == Average16InterpolatePixel)
@@ -4720,8 +4720,8 @@ MagickExport MagickBooleanType Interpola
     }
     case NearestInterpolatePixel:
     {
-      x_offset=(ssize_t) floor(x+0.5);
-      y_offset=(ssize_t) floor(y+0.5);
+      x_offset=(ssize_t) floor(ConstrainPixelOffset(x)+0.5);
+      y_offset=(ssize_t) floor(ConstrainPixelOffset(y)+0.5);
       p=GetCacheViewVirtualPixels(image_view,x_offset,y_offset,1,1,exception);
       if (p == (const Quantum *) NULL)
         {
@@ -4937,8 +4937,8 @@ MagickExport MagickBooleanType Interpola
   assert(source->signature == MagickCoreSignature);
   assert(source_view != (CacheView *) NULL);
   status=MagickTrue;
-  x_offset=(ssize_t) floor(x);
-  y_offset=(ssize_t) floor(y);
+  x_offset=(ssize_t) floor(ConstrainPixelOffset(x));
+  y_offset=(ssize_t) floor(ConstrainPixelOffset(y));
   interpolate=method;
   if (interpolate == UndefinedInterpolatePixel)
     interpolate=source->interpolate;
@@ -4955,8 +4955,8 @@ MagickExport MagickBooleanType Interpola
       if (interpolate == Average9InterpolatePixel)
         {
           count=3;
-          x_offset=(ssize_t) (floor(x+0.5)-1);
-          y_offset=(ssize_t) (floor(y+0.5)-1);
+          x_offset=(ssize_t) (floor(ConstrainPixelOffset(x)+0.5)-1);
+          y_offset=(ssize_t) (floor(ConstrainPixelOffset(y)+0.5)-1);
         }
       else
         if (interpolate == Average16InterpolatePixel)
@@ -5220,8 +5220,8 @@ MagickExport MagickBooleanType Interpola
     }
     case NearestInterpolatePixel:
     {
-      x_offset=(ssize_t) floor(x+0.5);
-      y_offset=(ssize_t) floor(y+0.5);
+      x_offset=(ssize_t) floor(ConstrainPixelOffset(x)+0.5);
+      y_offset=(ssize_t) floor(ConstrainPixelOffset(y)+0.5);
       p=GetCacheViewVirtualPixels(source_view,x_offset,y_offset,1,1,exception);
       if (p == (const Quantum *) NULL)
         {
@@ -5504,8 +5504,8 @@ MagickExport MagickBooleanType Interpola
   assert(image->signature == MagickCoreSignature);
   assert(image_view != (CacheView *) NULL);
   status=MagickTrue;
-  x_offset=(ssize_t) floor(x);
-  y_offset=(ssize_t) floor(y);
+  x_offset=(ssize_t) floor(ConstrainPixelOffset(x));
+  y_offset=(ssize_t) floor(ConstrainPixelOffset(y));
   interpolate=method;
   if (interpolate == UndefinedInterpolatePixel)
     interpolate=image->interpolate;
@@ -5524,8 +5524,8 @@ MagickExport MagickBooleanType Interpola
       if (interpolate == Average9InterpolatePixel)
         {
           count=3;
-          x_offset=(ssize_t) (floor(x+0.5)-1);
-          y_offset=(ssize_t) (floor(y+0.5)-1);
+          x_offset=(ssize_t) (floor(ConstrainPixelOffset(x)+0.5)-1);
+          y_offset=(ssize_t) (floor(ConstrainPixelOffset(y)+0.5)-1);
         }
       else if (interpolate == Average16InterpolatePixel)
         {
@@ -5849,8 +5849,8 @@ MagickExport MagickBooleanType Interpola
     }
     case NearestInterpolatePixel:
     {
-      x_offset=(ssize_t) floor(x+0.5);
-      y_offset=(ssize_t) floor(y+0.5);
+      x_offset=(ssize_t) floor(ConstrainPixelOffset(x)+0.5);
+      y_offset=(ssize_t) floor(ConstrainPixelOffset(y)+0.5);
       p=GetCacheViewVirtualPixels(image_view,x_offset,y_offset,1,1,exception);
       if (p == (const Quantum *) NULL)
         {