[jira] [Work logged] (NET-663) NullPointerException when FTPClient remote verification fails

classic Classic list List threaded Threaded
1 message Options
Reply | Threaded
Open this post in threaded view
|

[jira] [Work logged] (NET-663) NullPointerException when FTPClient remote verification fails

JIRA jira@apache.org

     [ https://issues.apache.org/jira/browse/NET-663?focusedWorklogId=247752&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-247752 ]

ASF GitHub Bot logged work on NET-663:
--------------------------------------

                Author: ASF GitHub Bot
            Created on: 23/May/19 22:32
            Start Date: 23/May/19 22:32
    Worklog Time Spent: 10m
      Work Description: mshenfield commented on pull request #40: [NET-663] Retrieve socket host before closing in remote verification
URL: https://github.com/apache/commons-net/pull/40
 
 
   This retrieves the socket host before closing the socket when remote verification fails in order to get a non-null host address. In [NET-663](https://issues.apache.org/jira/browse/NET-663), `socket.getInetAddress()` returned a null after the socket was closed, causing a `NullPointerException` instead of the more helpful error message intended.
 
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
[hidden email]


Issue Time Tracking
-------------------

    Worklog Id:     (was: 247752)
    Time Spent: 20m  (was: 10m)

> NullPointerException when FTPClient remote verification fails
> -------------------------------------------------------------
>
>                 Key: NET-663
>                 URL: https://issues.apache.org/jira/browse/NET-663
>             Project: Commons Net
>          Issue Type: Bug
>          Components: FTP
>    Affects Versions: 3.6
>         Environment: OS: Linux
>            Reporter: Max Shenfield
>            Priority: Minor
>              Labels: NullPointerException
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> At L934 of the {{FTPClient}} code, Apache does a check to see whether the data and control connections are at the same IP address ({{verifyRemote}}). If they differ, the data connection socket is closed and an exception is raised.  This can be disabled, but is the default behavior ({{__remoteVerificationEnabled = true}}).
> I'm connecting to the FTP via a proxy.  In my setup, the L934-939 code path where {{verifyRemote}} returns false always raises a {{java.lang.NullPointerException}}.  {{socket.getInetAddress()}} seems to return {{null}} after {{socket.close}} is called, leading to {{socket.getInetAdress().getHostAddress()}} to raise the {{java.lang.NullPointerException}} at L938.   This obfuscates a really useful error message ("Host attempting data connection is not the same as server") with a difficult to debug {{NullPointerException}}.
> Example State:
> {code}
> this.__remoteVerificationEnabled -> true
> this.getRemoteAddress().toString() -> "ftp.example.com/987.654.321.000"
> socket.getInetAddress().toString() -> "/123.456.789.000"
> {code}



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)