0031585: Access Violation while creating fillet - ChFi3d_Builder::PerformIntersectionAtEnd

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Date Submitted

Last Update

0031585

Community

[OCCT] OCCT:Modeling Algorithms

public

2020-05-30 16:55

Reporter

abdullah

Assigned To

msv

Priority

normal

Severity

crash

Status

new

Resolution

open

Platform

Linux

Debian 6.0

OS Version

64 bit

Product Version

[OCCT] 7.3.0

Target Version

Fixed in Version

Summary

0031585: Access Violation while creating fillet - ChFi3d_Builder::PerformIntersectionAtEnd

Description

This bug is reported against, git commit ae58f70718a089f84178d45a1bf9bee586d52d80 (master branch on 30 may 2020, OCC_VERSION 7.4.1). It is also present in 7.3.0.

I attach a patch as a possible solution.

In:

void ChFi3d_Builder::PerformIntersectionAtEnd(const Standard_Integer Index)

TopoDS_Edge Edge[nn];

is defined with:

const Standard_Integer nn=15;

At line 2020, in the loop "while (!trouve)"

there is no check of the index nb used for array "Edge", in the example described below, nb takes value 15 => Edge[15] which causes an Access Violation.

I have not investigated the actual reason why it is not found.

The possible solution I propose is to check the index and throw an exception to avoid the crash.

Steps To Reproduce

This access violation was reported in the FreeCAD project:
https://tracker.freecadweb.org/view.php?id=4129 [^]
https://forum.freecadweb.org/viewtopic.php?f=3&t=38590 [^]

Creating a draw.exe example of this is not straight-forward. In my system I build Opencascade from master in Debug mode and debug a locally build debug version of FreeCAD using it.

As it involves an access violation, I think you will be interested in this report and possible solution, even though I do not actually provide a draw example.

If you need further information or want to provide me with an alternative solution so that I check, I am happy to contribute.

Additional information
and documentation updates

diff --git a/src/ChFi3d/ChFi3d_Builder_C1.cxx b/src/ChFi3d/ChFi3d_Builder_C1.cxx
index 369d4dcd7a..339b662691 100644
--- a/src/ChFi3d/ChFi3d_Builder_C1.cxx
+++ b/src/ChFi3d/ChFi3d_Builder_C1.cxx
@@ -2020,0 +2021 @@ void ChFi3d_Builder::PerformIntersectionAtEnd(const Standard_Integer Index)
+ if (nb>=nn) throw Standard_Failure("IntersectionAtEnd : the max number of edges reached");

Issue History
Date Modified	Username	Field	Change
2020-05-30 16:55	abdullah	New Issue
2020-05-30 16:55	abdullah	Assigned To	=> msv

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