From: Cristy <urban-warrior@imagemagick.org>
Date: Tue, 23 Jan 2018 17:54:47 +0000 (-0500)
Subject: Eliminate a composite divide by zero
X-Git-Tag: 7.0.7-23~290
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ad52ba87abe91cf4d09bc8b761512eb35914d236;p=imagemagick

Eliminate a composite divide by zero
Credit OSS Fuzz
---

diff --git a/MagickCore/composite.c b/MagickCore/composite.c
index 80f230aa4..5b8604406 100644
--- a/MagickCore/composite.c
+++ b/MagickCore/composite.c
@@ -1761,8 +1761,10 @@ MagickExport MagickBooleanType CompositeImage(Image *image,
                 pixel=QuantumRange*gamma*(Dca*(1.0-Sa));
                 break;
               }
-            pixel=QuantumRange*gamma*(Sa*Da-Sa*Da*MagickMin(1.0,(1.0-Dca/Da)*Sa/
-              Sca)+Sca*(1.0-Da)+Dca*(1.0-Sa));
+            pixel=0.0;
+            if ((IsNaN(Da) != MagickFalse) && (IsNaN(Sca) != MagickFalse))
+              pixel=QuantumRange*gamma*(Sa*Da-Sa*Da*MagickMin(1.0,(1.0-Dca/Da)*
+                Sa/Sca)+Sca*(1.0-Da)+Dca*(1.0-Sa));
             break;
           }
           case ColorDodgeCompositeOp: