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From "Chris Collins (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (NET-620) Strict CRLF handling in Commons-NET FTP breaks compatibility with some FTP servers
Date Fri, 03 Mar 2017 13:18:46 GMT

    [ https://issues.apache.org/jira/browse/NET-620?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15894325#comment-15894325
] 

Chris Collins commented on NET-620:
-----------------------------------

Ok, so it appears that the breaking up of \_connectAction\_() and \_connectAction\_(Reader
reader) was done to re-use existing readers when possible instead of creating new ones, but
doesn't allow you do define your own reader and pass it in.

This appears to be due to \_input\_ not being initialized until SocketClient.\_connectAction\_
is called through the chain mentioned in the previous comment. I thought that maybe ToNetASCIIInputStream
might get input initialized if the inputstream was passed by reference but it doesn't appear
to. Through remote debugging I can clearly see that when the reader is passed in FTP.\_\_getReply:321
is definitely working on a null InputStream within the InputStreamReader. If I reformat FTPClient.\_connectAction\_
like this for testing purposes everything works fine including the newlines getting fixed:

{noformat}
    protected void _connectAction_(Reader socketIsReader) throws IOException {
        super._connectAction_(); // sets up _input_ and _output_
        if(socketIsReader == null) {
            _controlInput_ =
                    new CRLFLineReader(new InputStreamReader(new ToNetASCIIInputStream(_input_),
getControlEncoding()));
        } else {
            _controlInput_ = new CRLFLineReader(socketIsReader);
        }
{noformat}

Looking at these results and how things are organized and where initializations happen does
this Null InputStream make sense to you as well Sebb?

> Strict CRLF handling in Commons-NET FTP breaks compatibility with some FTP servers
> ----------------------------------------------------------------------------------
>
>                 Key: NET-620
>                 URL: https://issues.apache.org/jira/browse/NET-620
>             Project: Commons Net
>          Issue Type: Bug
>          Components: FTP
>    Affects Versions: 3.3, 3.4, 3.5, 3.6
>         Environment: Java RHEL Linux
>            Reporter: Chris Collins
>
> The fix for FTP.java in NET-401 to switch from using BufferedReader to CRLFLineReader
breaks the ability to connect to servers that have varying LF and CRLF line termination in
the banner.
> I've run into 2 different cases with slightly different banner configs, one where you
end up hung indefinitely by not reading far enough (this is the sigquit from when it is hung):
> 1. Thread=FTP Provider Protocol Provider Thread: class com.xxxx.xxxxx.xxx (00007F35A1AF4A00)
Status=Running
>        at java/net/SocketInputStream.socketRead0(Ljava/io/FileDescriptor;[BIII)I (Native
Method)
>        at java/net/SocketInputStream.read([BIII)I (SocketInputStream.java:164) (Compiled
Code)
>        at java/net/SocketInputStream.read([BII)I (SocketInputStream.java:134) (Compiled
Code)
>        at sun/nio/cs/StreamDecoder.readBytes()I (StreamDecoder.java:323) (Compiled Code)
>        at sun/nio/cs/StreamDecoder.implRead([CII)I (StreamDecoder.java:365) (Compiled
Code)
>        at sun/nio/cs/StreamDecoder.read([CII)I (StreamDecoder.java:211) (Compiled Code)
>        at java/io/InputStreamReader.read([CII)I (InputStreamReader.java:206) (Compiled
Code)
>        at java/io/BufferedReader.fill()V (BufferedReader.java:166) (Compiled Code)
>        at java/io/BufferedReader.read()I (BufferedReader.java:187) (Compiled Code)
>        at org/apache/commons/net/io/CRLFLineReader.readLine()Ljava/lang/String; (CRLFLineReader.java:58)
>        at org/apache/commons/net/ftp/FTP.__getReply(Z)V (FTP.java:357)
>        at org/apache/commons/net/ftp/FTP.__getReply()V (FTP.java:300)
>        at org/apache/commons/net/ftp/FTP._connectAction_(Ljava/io/Reader;)V (FTP.java:438)
>        at org/apache/commons/net/ftp/FTPClient._connectAction_(Ljava/io/Reader;)V (FTPClient.java:962)
>        at org/apache/commons/net/ftp/FTPClient._connectAction_()V (FTPClient.java:950)
>        at org/apache/commons/net/SocketClient._connect(Ljava/net/InetAddress;ILjava/net/InetAddress;I)V
(SocketClient.java:244)
>        at org/apache/commons/net/SocketClient.connect(Ljava/net/InetAddress;I)V (SocketClient.java:181)
> 2. And one where you error out by reading too far and getting a null back:
> Caused by:
> org.apache.commons.net.ftp.FTPConnectionClosedException: Connection closed without indication.
>     at org.apache.commons.net.ftp.FTP.__getReply(FTP.java:317)
>     at org.apache.commons.net.ftp.FTP.__getReply(FTP.java:294)
>     at org.apache.commons.net.ftp.FTP.sendCommand(FTP.java:483)
>     at org.apache.commons.net.ftp.FTP.sendCommand(FTP.java:608)
>     at org.apache.commons.net.ftp.FTP.user(FTP.java:753)
>     at org.apache.commons.net.ftp.FTPClient.login(FTPClient.java:1034)
> I do have hex data available to show the source data, but the end result is there's a
mix of 0d0a (CRLF) and 0a (LF) termination in the FTP banner (220-)
> I can modify the library to undo the NET-401 change, but ideally it'd be nice to have
a strictNewline type of setting you could set on the FTPClient object to decide if you want
to be ultra-strict, or ultra compatible. I will be filing a defect with Cisco about this as
well, but it would be great if the FTPClient had the option to handle it instead of forced
compatibility with no options to relax it.
> This is kind of hinted at in one of the comments on NET-402 by Bogdan Drozdowski on 12/Apr/11
> "So, on one hand, we stop supporting non-conforming servers (which could mean that we're
supporting less servers now), but on the other hand we're fixing a bug that someone has found
in a real-life system."
> Giving users the option to relax the conformity requirements (but strict by default)
would allow the end user to choose the option.
> Any thoughts on this?



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