Fixed use of uninitialized value (https://oss-fuzz.com/v2/testcase-detail/63203099017...

diff --git a/coders/pnm.c b/coders/pnm.c
index 08c1989cb840989aa19fc36fa857c1031390bb22..66ca8afc0edfb1f83061ef43a79ac61ed1554235 100644 (file)
--- a/coders/pnm.c
+++ b/coders/pnm.c
@@ -301,8 +301,8 @@ static Image *ReadPNMImage(const ImageInfo *image_info,ExceptionInfo *exception)
             char
               scale[MagickPathExtent];
 
-            (void) ReadBlobString(image,scale);
-            quantum_scale=StringToDouble(scale,(char **) NULL);
+            if (ReadBlobString(image,scale) != (char *) NULL)
+              quantum_scale=StringToDouble(scale,(char **) NULL);
           }
         else
           {