From: Cristy <urban-warrior@imagemagick.org>
Date: Wed, 7 Mar 2018 01:32:58 +0000 (-0500)
Subject: Fix possible out of bounds issue
X-Git-Tag: 7.0.7-26~74
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=69c4513a4fb5f71421a21643edb53de53d3864a6;p=imagemagick

Fix possible out of bounds issue
---

diff --git a/MagickCore/fx.c b/MagickCore/fx.c
index 583a478df..52b206da8 100644
--- a/MagickCore/fx.c
+++ b/MagickCore/fx.c
@@ -2372,7 +2372,8 @@ static double FxEvaluateSubexpression(FxInfo *fx_info,
         (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
           "ParenthesisNestedTooDeeply","`%s'",expression);
       (void) CopyMagickString(subexpression,expression+1,MagickPathExtent);
-      subexpression[strlen(subexpression)-1]='\0';
+      if (strlen(subexpression) != 0)
+        subexpression[strlen(subexpression)-1]='\0';
       gamma=FxEvaluateSubexpression(fx_info,channel,x,y,subexpression,depth,
         beta,exception);
       (*depth)--;