From eee409d4e73d9676cbf8bec3aa71c4cd2a83a79a Mon Sep 17 00:00:00 2001
From: Amy Bowersox <abowersox@carbonblack.com>
Date: Tue, 10 Dec 2019 14:45:02 -0700
Subject: [PATCH] add an infinite loop detector

---
 src/devctxt.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/devctxt.c b/src/devctxt.c
index bafd68e..c6a41bb 100755
--- a/src/devctxt.c
+++ b/src/devctxt.c
@@ -29,6 +29,7 @@ static BOOL line_clip(PINT32 output, INT32 x1, INT32 y1, INT32 x2, INT32 y2, INT
 {
   BYTE outcode1, outcode2;
   INT32 tmp;
+  int nloop = 0;
   
   Log(LDEBUG, "clipping line from (%d, %d) to (%d, %d) against bounding box (%d, %d, %d, %d)", x1 >> CPX, y1 >> CPX, x2 >> CPX, y2 >> CPX,
       xmin >> CPX, ymin >> CPX, xmax >> CPX, ymax >> CPX);
@@ -36,6 +37,11 @@ static BOOL line_clip(PINT32 output, INT32 x1, INT32 y1, INT32 x2, INT32 y2, INT
   /* Cohen-Sutherland line-clipping algorithm (see Foley & Van Dam, pp. 145-149) */
   for (;;)
   {
+    if (++nloop == 20)
+	{
+	  Log(LDEBUG, "POSSIBLE INFINITE LOOP DETECTED - REJECTING");
+	  return FALSE;
+	}
     outcode1 = line_clip_outcode(x1, y1, xmin, ymin, xmax, ymax);
 	outcode2 = line_clip_outcode(x2, y2, xmin, ymin, xmax, ymax);
 	if ((outcode1 & outcode2) != 0)