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https://issues.apache.org/jira/browse/SSHD-1308?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17623351#comment-17623351
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dgü commented on SSHD-1308:
---------------------------
I don't know how SSH servers run remote commands.
If they run remote commands by a shell such as _sh, cmd_ then the workaround
above may cause addional child shell unless SSH servers are aware of remote
command is a shell and no need to run its own shell.
If they run remote commands directly without a shell, there will be no
additionall shell already.
This is from _OpenSSH 7.4p1_ on Linux:
{{oracle@ubsia ~]$ pstree}}
{{systemd─┬─NetworkManager───2*[\{NetworkManager}]}}
{{ ├─agetty}}
{{ ├─auditd───\{auditd}}}
{{ ├─chronyd}}
{{ ├─crond}}
{{ ├─dbus-daemon───\{dbus-daemon}}}
{{ ├─gssproxy───5*[\{gssproxy}]}}
{{ ├─lvmetad}}
{{ ├─polkitd───6*[\{polkitd}]}}
{{ ├─rhnsd}}
{{ ├─rsyslogd───2*[\{rsyslogd}]}}
{{ ├─smartd}}
{{ ├─sshd─┬─sshd───sshd───bash───pstree}}
{{ │ ├─sshd───sshd───bash───rman───oracle <-- RMAN MANUALLY}}
{{ │ ├─sshd───sshd───bash}}
{{ │ └─sshd───sshd───rman───oracle <-- RMAN BY MINA SSHD by
}}{{sh -c '...' }}{{}}
{{ ├─systemd-journal}}
{{ ├─systemd-logind}}
{{ ├─systemd-udevd}}
{{ └─tuned───4*[\{tuned}]}}
{{[oracle@ubsia ~]$ }}
As seen above there is no additional _sh_ command in the process tree when
remote command is run by sh -c '...'. OpenSSH Server may have optimized it, or
something else that I don't know.
This is out of the topic. I wrote if someone needs in future.
> No exception is thrown if setting environment variable is ignored by SSH
> server
> -------------------------------------------------------------------------------
>
> Key: SSHD-1308
> URL: https://issues.apache.org/jira/browse/SSHD-1308
> Project: MINA SSHD
> Issue Type: Improvement
> Affects Versions: 2.9.1
> Environment: Java 8
> Reporter: dgü
> Priority: Major
>
> Hello!
> If an environment variable set by
> _org.apache.sshd.client.session.ClientSession#createExecChannel(command,null,env)_
> is ignored by SSH server and exit code returns 0, then this may cause
> unexpected behaviour in client application.
> For example, client application may do different tasks when an environment
> variable is set and not set. In both cases, client application may return 0.
> Client application may assume that it worked successfully. But, indeed its
> environment variable is ignored and worked as if environment variable is not
> set.
> is it possible throw an exception if setting environment variable is ignored
> by SSH server ?
> Thanks in advance...
>
>
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