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https://issues.apache.org/jira/browse/NIFI-4040?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Koji Kawamura updated NIFI-4040:
--------------------------------
Affects Version/s: 1.0.0
Status: Patch Available (was: Open)
> ListSFTP fails to retrieve user home directory for certain user accounts
> ------------------------------------------------------------------------
>
> Key: NIFI-4040
> URL: https://issues.apache.org/jira/browse/NIFI-4040
> Project: Apache NiFi
> Issue Type: Bug
> Components: Extensions
> Affects Versions: 1.0.0
> Reporter: Koji Kawamura
> Assignee: Koji Kawamura
>
> For some reason, when ListSFTP tries to get users home directory using
> com.jcraft.jsch.ChannelSftp.getHome() method, it fails with following error
> with certain user accounts:
> {code}
> 2017-04-05 11:33:37,645 ERROR [Timer-Driven Process Thread-20]
> o.a.nifi.processors.standard.ListSFTP
> java.io.IOException: Failed to obtain connection to remote host due to 2:
> File not found
> at
> org.apache.nifi.processors.standard.util.SFTPTransfer.getChannel(SFTPTransfer.java:447)
> ...
> Caused by: com.jcraft.jsch.SftpException: File not found
> at com.jcraft.jsch.ChannelSftp.throwStatusError(ChannelSftp.java:2873)
> ~[jsch-0.1.54.jar:na]
> at com.jcraft.jsch.ChannelSftp._realpath(ChannelSftp.java:2367)
> ~[jsch-0.1.54.jar:na]
> at com.jcraft.jsch.ChannelSftp.getHome(ChannelSftp.java:2437)
> ~[jsch-0.1.54.jar:na]
> at
> org.apache.nifi.processors.standard.util.SFTPTransfer.getChannel(SFTPTransfer.java:443)
> ~[nifi-standard-processors-1.1.0.2.1.1.0-2.jar:1.1.0.2.1.1.0-2]
> {code}
> This happens when the library sends SSH_FXP_REALPATH(16) with an empty
> string. Server returned SSH_FXP_STATUS(101). According [SSH File Transfer
> Protocol|https://tools.ietf.org/id/draft-ietf-secsh-filexfer-13.txt]
> specification, 101 means:
> {quote}
> The server MUST respond with SSH_FXP_STATUS(SSH_FX_OP_UNSUPPORTED) if it
> receives a packet it does not recognize.
> {quote}
> So, it indicates that client library sends a request packet that the server
> didn't understand. Since this error happens with certain user account, based
> on their home directly, there might be a combination that causes this issue.
> Although those user accounts fail with getHome method, they can list files if
> we don't call getHome(). (Confirmed by commenting out the getHome call)
> The home directory is used to address a relative 'Remote Path' to a full path
> by PutSFTP and PutFTP. The fullpath is only used for 'Transit URI' for their
> SEND provenance event.
> Summary:
> * There is no way to alter getHome method behavior from NiFi code base
> * Without getHome those user accounts can list the problematic FTP server
> * The value retrieved by getHome is only used for provenance event and it
> works without it
> From above observations, I propose to wrap getHome call with try/catch
> clause, and if it fails just log some message then continue.
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